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991.
The accurate estimation of sideslip angle is necessary for many vehicle control systems. The detection of sliding and skidding
is especially critical in emergency situations. In this paper, a sideslip angle estimation method is proposed that considers
severe longitudinal velocity variation over the short period of time during which a vehicle may lose stability due to sliding
or spinning. An extended Kalman filter (EKF) based on a kinematic model of a vehicle is used without initialization of the
inertial measurement unit to estimate vehicle longitudinal velocity. A dynamic compensation method that compensates for the
difference in the locations of the vehicle velocity sensor and the IMU in on-road vehicle tests is proposed. Evaluations with
a CarSim™ 27-degree-of-freedom (DOF) model for various vehicle test scenarios and with on-road tests using a real vehicle
show that the proposed sideslip angle estimation method can accurately predict sideslip angle, even when vehicle longitudinal
velocity changes significantly. 相似文献
992.
Constant velocity universal joints play a very important role in automotive drivelines. The traditional development method,
based on a physical prototype and experimenting, is time consuming and costly. This test-based method does not easily identify
rational design clues. Therefore, a virtual product development method, which is based on dynamics modeling and simulation,
is necessary. Virtual prototyping for a universal joint has been developed using the simulation software package MSC.ADAMS.
Dynamics simulation has been performed to predict and evaluate joint behaviors. This virtual product development method has
been implemented by the WanXiang Group Co., which is one of the most famous Chinese automotive component manufacturers. 相似文献
993.
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
994.
M. J. L. Boada B. L. Boada D. Garcia-Pozuelo V. Diaz 《International Journal of Automotive Technology》2011,12(6):821-829
The behaviour of the tyre plays an important role in the vehicle handling. An accurate tyre model that estimates these forces
and moments it is highly essential for the studies of vehicle behaviour. For the last ten years neural networks have attracted
a great deal of attention in vehicle dynamics and control. Neural networks have been effectively applied to model complex
systems due to their good learning capability. In this paper a recursive lazy learning method based on neural networks is
considered to model the tyre characteristics under combined braking and cornering. The proposed method is validated by comparison
with experimental obtained responses. Results show the estimated model correlates very well with the data obtained experimentally.
Moreover, the neural model proposed allows to include the asymetric tyre behaviour in the tyre model without difficulty. 相似文献
995.
M. H. Lee H. M. Lee K. S. Lee S. K. Ha J. I. Bae J. H. Park H. G. Park H. J. Choi H. H. Chun 《International Journal of Automotive Technology》2011,12(5):733-744
In this paper, a hardware-in-the-loop simulation (HILS) system was developed before the development of an electric power steering
(EPS) system in a vehicle. This study was focused on the establishment of the HILS system. Driving conditions are simulated
with the HILS system. The actual steering input parameters are confirmed on the monitor while driving the HILS system. The
steering forces observed in the simulation with the developed HILS system are similar to those in real vehicle tests. The
developed HILS system can be applied in the development of various types of EPS systems. 相似文献
996.
An experiment was conducted to characterize the effects of SOF on EGR cooler fouling. A removable singletube test rig combined with a soot generator was developed to represent an EGR cooler and diesel exhaust gas. The use of a soot generator, which controlled the size and concentration of soot particles, enabled independent variables to be completely controlled. Either n-dodecane or diesel lube oil as substitute SOFs were vaporized and injected into the test rig to evaluate their effects on the growth of PM deposits and the degradation performance of the EGR cooler. Coolant temperature, which seemed to be associated with SOF content, was chosen as an independent variable, and PM deposit mass per unit area and the effectiveness drop versus time increased as the coolant temperature decreased. The PM deposit mass per unit area and effectiveness drop had maximum values at a coolant temperature of 40°C for every n-dodecane injection rate. For substitute SOFs tested in this experiment, the deposit mass increased when either n-dodecane or diesel lube oil was injected, but the effect of lube oil was more significant. Diesel lube oil seemed to have a stronger effect on the reduction of thermal conductivity by filling pores in the deposits. When diesel lube oil was injected, the deposit mass per unit area increased 127% compared to dry soot without injection. The effectiveness drop after 10 hours increased only 12.5%. 相似文献
997.
This paper presents a system to identify road and non-road regions from monocular color images of paved and unpaved roads. Despite being a single object, the road in these images is subject to large changes in appearance due to environmental effects and track materials. This condition has challenged the practical application of road identification. The proposed system combines random forest with color correlogram to overcome such conditions and offers a classifier for road and non-road regions in traffic images. As a color feature, the color correlogram depicts the spatial correlation of color changes in an image. Using random forest, road identification is formulated as a learning paradigm. The combined effects of color correlograms and random forest create a robust system capable of identifying roads even in variable situations in real time. This combination is more effective than other combinations, such as a color histogram plus random forest, a color correlogram plus neural network, or a color histogram plus neural network. 相似文献
998.
The urban tram introduced recently has a low-floor structure for the convenience of passengers getting on and off. To adjust the low-floor level and improve performance on curves, most low-floor trams have IRWs (independently rotating wheels) with no central axle between the two wheels. Eliminating the central axle, however, creates several inherent problems, such as insufficient guiding force and excessive wear. To analyze these problems, a new analytical model is described in this paper to describe the dynamic characteristics of IRWs more precisely. This analytical model is developed to consider the effects of longitudinal creep in particular, which have been ignored in conventional analytical models of IRWs. In addition, a running stability analysis based on the newly developed analytical model is conducted to compare the critical speeds of IRW-axle vehicles and rigid-axle vehicles. The dynamic characteristics of an initial disturbance are compared to verify that the analytical model is effective in expressing the dynamic characteristics of IRWs. 相似文献
999.
In lean-DeNOX catalysis reactions, hydrogen is a good reducing agent in PGM catalysts as well as an effective promoter in
selective catalytic reduction reactions over base metal oxide catalysts. However, such a lean-DeNOX system, which uses hydrogen,
requires an on-board fuel reforming system applicable to internal combustion engines. In this study, catalytic partial oxidation
(CPOx) performance was tested in a laboratory for various reactants and hydrocarbon conditions. Volume concentrations of 5–10%
oxygen and 0-5% water vapor were used to simulate diesel exhaust, and n-C12H26 was used as the feedstock for the reforming reaction. In the CPOx of n-C12H26, the highest hydrogen selectivity was 64% and was achieved at 100,000 h-1 GHSV. Additionally, the C/O ratio was less than
unity in the absence of water vapor. However, as the water concentration was increased to 2.5 and 5.0 vol. % in the n-C12H26 CPOx reactions, the maximum hydrogen selectivity was increased from 64% in the absence of water to 70% and 75%, respectively.
This effect is a consequence of the water-gas shift reaction over the catalyst bed. Regarding oxygen concentration effects,
hydrogen selectivity slightly increased with increasing oxygen concentration from 10% to 15%. It was also found that the CPOx
reaction of n-C12H26 can be ignited at temperatures below 300 C. Accordingly, it can be concluded that CPOx is a useful and feasible device for
promoting diesel DeNOx catalysis in terms of hydrogen productivity and reaction initiation. 相似文献
1000.
Q. Fan J. Bian H. Lu L. Li J. Deng 《International Journal of Automotive Technology》2012,13(4):523-531
The first firing cycle is very important during cold-start for all types of spark ignition engines. In addition, the combustion characteristics of the first firing cycle affect combustion and emissions in the following cycles. However, the first-cycle fuel-air mixing, combustion and emissions generation within the cylinder of a two-stage direct-injection (TSDI) engine during cold start is not completely understood. Based on the total stoichiometric air-fuel ratio and local richer mixture startup strategy, the first-cycle firing and combustion characteristic at cold start were investigated in a two-stage direct injection (TSDI) gasoline engine. In addition, the effects of the first injection timing, second injection timing, 1st and 2nd fuel injection proportion and total excess air ratio on the in-cylinder pressure, heat release rate and accumulated heat release were analyzed on the basis of a cycle-by-cycle analysis. It is shown that a larger 2nd fuel injection amount and later 2nd injection timing are more beneficial to the firing of the first cycle in the case of a total excess air ratio of 1.0. The optimum 1st and 2nd injection timing fuel injection proportions are 120°CA ATDC during the intake stroke, 60°CA BTDC during the compression stroke and 1:1. In addition, the firing boundary is a 2nd injection timing later than 90°CA BTDC during the compression stroke in the case of the 1st injection timing from 60°CA to 180°CA ATDC during an intake stroke and involves a 1st and 2nd fuel injection proportion of 1:1 and an excess air ratio of 1.0. The study provides a detailed understanding of cold-start combustion characteristics and a guide for optimizing the reliable first-cycle firing at cold start. 相似文献