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601.
B. C. Choi S. K. Choi S. H. Chung J. S. Kim J. H. Choi 《International Journal of Automotive Technology》2011,12(2):183-191
Experimental and numerical analyses of laminar diffusion flames were performed to identify the effect of fuel mixing on soot
formation in a counterflow burner. In this experiment, the volume fraction, number density, and particle size of soot were
investigated using light extinction/scattering systems. The experimental results showed that the synergistic effect of an
ethylene-propane flame is appreciable. Numerical simulations showed that the benzene (C6H6) concentration in mixture flames was higher than in ethylene-base flames because of the increase in the concentration of
propargyl radicals. Methyl radicals were found to play an important role in the formation of propargyl, and the recombination
of propargyl with benzene was found to lead to an increase in the number density for cases exhibiting synergistic effects.
These results imply that methyl radicals play an important role in soot formation, particularly with regard to the number
density. 相似文献
602.
We analyzed the lubrication characteristics of a design-selected spiral groove liquid seal for the critical component, the
carrier, of a rotary vane-type fuel pump developed for external installation on fuel tanks for liquid phase LPG (liquefied
petroleum gas) injection (LPLi) vehicles, with the aim of fundamentally improving lubrication performance and so protecting
the carrier from early frictional wear damage at its suction face. The main reason for selecting a spiral groove pattern was
because the viscosity of liquid LPG is very low, comparable to that of air, and current commercial dry gas seals adopting
spiral grooves have been successfully employed in completely noncontacting applications. Utilizing the Galerkin finite element
lubrication analysis method, a detailed lubrication characteristic analysis of the seal was performed, and lubrication performance
optimization was performed by systematic parameter analyses of the design variables. Compared to the initial reference design,
the final optimized spiral groove seal design had a groove depth increased by 66.7% and an equilibrium seal clearance increased
by 65.3%. Our model also predicted that under a condition of equilibrium between the closing force of the pumping pressure
and the seal opening force, the optimally designed carrier spiral groove liquid seal was capable of maintaining a stable lubricating
film with sufficient axial stiffness and thereby demonstrated successful noncontact operation; in addition, leakage through
the seal was minimal. 相似文献
603.
C. -H. Lee J. -M. Lee M. -S. Choi C. -K. Kim E. -B. Koh 《International Journal of Automotive Technology》2011,12(2):193-198
Since the invention of automobiles, the need to know the braking performance of vehicles has been acknowledged. However, because
there are numerous design variables as well as nonlinearities in the braking system, it is difficult to predict the performance
accurately. In this paper, a computational program is developed to estimate the braking performance numerically. This synthetic
braking performance program accounts for pedal force, pedal travel and deceleration of braking parts, such as master cylinder,
booster, valve, brake pad, rotor, and hoses. To improve the accuracy of program, a semi-empirical model of a braking system
is introduced by using the empirical test data of pad compression, hose expansion and the friction coefficient between the
pad and rotor. The accuracy of the estimation is evaluated by comparing it to the actual vehicle test results. The developed
program is easy for the brake system engineers to manipulate and it can be used in the development of new vehicles by incorporating
the graphical presentations. 相似文献
604.
This paper presents a methodology to optimize the sizing of the energy and power components in a fuel cell electric vehicle from the driving mission (which includes driving cycles, a specified acceleration and autonomy requirements). The fuel cell and the Energy Storage System associated (battery or/and ultra capacitor) design parameters are the numbers of series and parallel branches respectively Nsi and Npi. They are set so as to minimize the objective function that includes mass, cost, fulfilling the performance requirements and respect the technological constraints of each power component through a penalty function. The methodology is based on a judicious combination of Matlab-Simulink® for the global simulation and a dedicated software tool Pro@Design®. Both are well suited to treat inverse problems for the optimization. An application for a fuel cell/battery powertrain illustrates the feasibility of the proposed methodology. 相似文献
605.
J. K. Kim Y. J. Kim W. H. Yang Y. C. Park K.-H. Lee 《International Journal of Automotive Technology》2011,12(3):375-381
This study proposes a structural design method for an outer tie rod installed in a passenger car. The weight of the outer
tie rod is optimized by using the aluminum alloy Al6082M, which is developed as a steel-substitute material, and applying
structural optimization techniques. The high strength aluminum with improved mechanical properties was developed to reduce
the weight of the outer tie rod. The newly developed aluminum alloy Al6082M is applied as the material of the outer tie rod.
The static strength due to inertia force, durability and buckling performances are considered in the structural design of
the outer tie rod. At the proto design stage of a new outer tie rod, it is cost-effective to utilize FE (finite element) analysis
to predict each of these performances. In addition, the current trend in the structural design of automobile parts is to use
optimization techniques to reduce the weights of the parts. First, for an arbitrary base design, the static strength, the
life cycle and the buckling load are calculated to check whether the design satisfies its criteria. Then, the critical performance
is selected so as to include its loading condition only in the optimization process. In this study, the metamodel based optimization
process using kriging is adopted to obtain the minimum weight satisfying the critical design requirement. Then, the feasibility
of the determined optimum shape is investigated against the other performances. Finally, the optimum design of outer tie rod
is modified by considering forging efficiency. The performances of the final design are investigated through simulation and
experiment. 相似文献
606.
M. M. Da Silva R. H. Cunha A. C. Neto 《International Journal of Automotive Technology》2012,13(6):915-922
In the field of vehicle dynamics, commercial software can aid the designer during the conceptual and detailed design phases. Simulations using these tools can quickly provide specific design metrics, such as yaw and lateral velocity, for standard maneuvers. However, it remains challenging to correlate these metrics with empirical quantities that depend on many external parameters and design specifications. This scenario is the case with tire wear, which depends on the frictional work developed by the tire-road contact. In this study, an approach is proposed to estimate the tire-road friction during steady-state longitudinal and cornering maneuvers. Using this approach, a qualitative formula for tire wear evaluation is developed, and conceptual design analyses of cornering maneuvers are performed using simplified vehicle models. The influence of some design parameters such as cornering stiffness, the distance between the axles, and the steer angle ratio between the steering axles for vehicles with two steering axles is evaluated. The proposed methodology allows the designer to predict tire wear using simplified vehicle models during the conceptual design phase. 相似文献
607.
In this study, a combined system consisting of a heat pump and a PTC heater was developed as a heating unit in electric vehicles. The system consists of a compressor, a condenser, an evaporator, an expansion device and a PTC heater. Experiments were conducted to examine the steady-state performance and dynamic characteristics of this system. The compressor speed, outdoor air inlet temperature, and indoor air inlet temperature were varied, and the performance of the system was experimentally investigated. The heating capacity, compressor power consumption and COP were obtained. Warm-up experiments were performed to investigate the dynamic characteristics of the system with a heat load of 1.5 kW in the indoor chamber. For the heat pump system, the PTC heater and the combined system, the heating performance and efficiency were investigated to determine an optimal control method. The results of this study agree well with the experimental results available in literature. This study provides experimental data of good quality for heating system design and the development of electric vehicles. 相似文献
608.
Q. -C. Cai K. -H. Lee W. -L. Song C. -H. Lee Y. Lee 《International Journal of Automotive Technology》2012,13(5):751-757
Tripod constant velocity (TCV) joints are common components in automotive and mechanical applications. The benefits of the TCV joint are its high plunge capacity and high torque capacity. During power transmission, the friction inside the joint generates an axial force according to the kinematics. This force causes noise and vibration problems. In this study, a simplified multi-body dynamic model based on a phenomenological TCV joint friction model is developed. This model considers the generated axial force (GAF) of a TCV joint with different lubricate conditions. The efficiency and accuracy are verified by comparison with other prediction models and experiments. Thus, this model can be used to design and control the manufacture process of TCV joints. 相似文献
609.
S. W. Lee Y. S. Cho W. C. Choi J. H. Lee Y. J. Park 《International Journal of Automotive Technology》2012,13(7):1149-1157
This study aims to investigate the combustion characteristics of mixed fuel of liquefied propane gas (LPG) and biodiesel under compression ignition (CI) in an effort to develop highly efficient and environmentally friendly mixed fuelbased CI engines. Although LPG fuel is known to be eco-friendly due to its low CO2 emission, LPG has not yet been widely applied for highly efficient CI engines because of its low cetane number and is usually mixed with other types of CI-friendly fuels. In this study, a number of experiments were prepared with a constant volume chamber (CVC) setup to understand the fundamental combustion characteristics of mixed fuel with LPG and biodiesel in two weight-based ratios and exhaust gas recirculation (EGR) conditions. The results from the current investigations verify the applicability of mixed fuel of LPG and biodiesel in CI engines with a carefully designed combustion control strategy that maximizes the benefits of the mixed fuel. Based on the results of this study, ignition is improved by increasing the cetane value by using higher blending ratios of biodiesel. As the blending ratios of biodiesel increased, CO and HC decreased and CO2 and NOx increases. 相似文献
610.
J. -K. Kim E. S. Yim C. H. Jeon C. -S. Jung B. H. Han 《International Journal of Automotive Technology》2012,13(2):293-300
This study examines the cold performance of biodiesel blends in a passenger car and a light duty truck at −16 °C and −20 °C.
Six different types of biodiesels derived from soybean oil, waste cooking oil, rapeseed oil, cottonseed oil, palm oil and
jatropha oil were blended with different volume ratios (B5 (5 vol. % biodiesel — 95 vol. % diesel), B10 and B20). The cold
filter plugging point (CFPP) and the cloud point had an effect on the startability and driveability of both the passenger
car and the light duty truck. The startability and driveability of the passenger car with all biodiesel blends (B5) were generally
good at −20 °C. In the light duty truck, biodiesel blends (B10 and B20) of soybean, waste cooking, rapeseed and jatropha tended
to be good at −20 °C in the startability and driveability tests than the biodiesel blends (B10 and B20) of cottonseed and
palm. In particular, the palm biodiesel blend (B10) failed at −20 °C, and the palm biodiesel blend (B20) also failed at −16
°C in the startability test. The cold flow properties of biodiesel dictate that the length of the hydrocarbon chains and the
presence of unsaturated structures significantly affect the low temperature properties of biodiesel. 相似文献