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991.
沥青层应变传感器数据采集及处理方法研究 总被引:1,自引:0,他引:1
介绍了沥青路面电阻应变传感器的基本原理,分析了数据采集过程中初始电压达到极限状态的原因和调整方法,通过试验分析确定了高速车轮荷载和FWD荷载作用下应变传感器数据采集系统的合理采集频率,最后结合应力应变传感器在动态荷载作用下的响应规律,总结了将电阻应变传感器电压信号转换为应变信号的数据处理方法. 相似文献
992.
J. H. Song J. X. Wang H. B. Tang X. J. Mao B. Zhuo 《International Journal of Automotive Technology》2009,10(4):523-528
A controller for a diesel hybrid electric vehicle based on a V-cycle development approach is investigated in this paper. The
hardware and infra program of the Hybrid Control Unit (HCU) are discussed in detail. The hardware system is designed based
on circuit simulation; while the infra system is written with assemble language. Time sharing mode, buffer sharing mode and
multi-task schedule method are used to ensure real-time communication in the infra program design. Based on multi-thread technology,
hardware in loop test system is also designed. The hardware in loop and bench tests show that the controller could meet the
requirements of the hybrid electric vehicle (HEV) and communicate in real-time. Circuit simulation, HCU, infra program and
hardware in loop test form the effective V-cycle development platform to design a hardware system for a diesel HEV controller. 相似文献
993.
In this paper, we present a method for estimating the natural frequencies of various engine valve springs such as constant
pitch, two-step variable pitch, three-step variable pitch, and progressive springs. Since a valve spring’s surging amplitude
is magnified when the spring’s natural frequency coincides with the frequency of the cam profile harmonic components, estimating
the natural frequency of the spring is the first step in predicting valve spring surging phenomena. A new method for calculating
the valve spring’s natural frequency is proposed in this paper that considers the end coil effect. This method predicts not
only the natural frequency of a helical spring at a fixed number of active turns, but also the change in the natural frequency
as the spring is compressed. The experimental results demonstrate that nonlinear characteristics of engine valve springs can
be predicted from the given initial pitch curves. 相似文献
994.
B. K. Han M. K. Cho C. Kim C. H. Lim J. J. Kim 《International Journal of Automotive Technology》2009,10(4):469-474
An efficient multibody dynamic model was developed to predict the vibrating transmitted gear forces of loaded and unloaded
pairs of helical gears simultaneously at all speeds. The model can also calculate the bearing forces of a manual transmission
that, in turn, may be converted to rattling noises. The bending of meshing gear teeth and torsional flexibility of transmission
shafts were considered and embodied effectively in the multibody dynamic model by calculating the tooth bending stiffness
and adding a torsion spring on a shaft section between two gears, respectively. The reactive forces on teeth and bearings
were calculated and compared using three different models that were developed for this study — an equivalent model, a rigid-body
model, and a frequency-based model. The equivalent model took only 58% computation time, compared to the frequency-based method,
even though the two showed very similar results. 相似文献
995.
High tension bolts in critical joints in internal combustion engines are susceptible to fatigue failure. Computeraided bolted
joint design procedures require knowledge of the dependence of bolt fatigue limit on the mean stress and ultimate tensile
strength. This dependence is investigated with staircase fatigue limit tests. The test results show that when the bolt fatigue
limit is estimated with the nominal stress of the bolt, it decreases with increasing tensile strength and nominal mean stress.
However, there is a range of the nominal mean stress where the bolt fatigue limit is almost constant. The test results are
interpreted with finite element analysis. 相似文献
996.
Design of conformal cooling channels for an automotive part 总被引:2,自引:0,他引:2
The cooling system plays a crucial role in determining the productivity and quality of an injection molding process. With
the current growth of Solid Freeform Fabrication (SFF) techniques, mold designers have been striving for not only improvement
in cooling system performance but also for a method to do so automatically. In this paper, a method is proposed for developing
a conformal cooling system that facilitates uniform cooling over the entire mold surface with minimum cycle time. Based on
the temperature distribution after the filling stage, the mold surface is split into zones which will be cooled by optimized
subconformal channels obtained from the optimization process. The optimization process in which the objective function is
stated as minimization of the cooling time with boundaries ensuring a realistic design will optimize the cooling system layout
in terms of cooling channel size and location. Finally, all subcooling channels are combined to generate the entire conformal
cooling system for the injection mold. 相似文献
997.
Interior sound field refinement of a passenger car using modified panel acoustic contribution analysis 总被引:3,自引:0,他引:3
Panel acoustic contribution analysis (PACA) is a practical engineering tool for the reduction of interior structure-borne
noise in passenger cars. In this study, the current PACA method has been improved for sound field refinement of the entire
interior. Two new parameters, the “acoustic contribution sum” and the “total sound field contribution”, are introduced to
analyze the interior sound field characterized with multiple field points and sound pressure peaks, and to evaluate the integrated
acoustic contributions of auto body panels. In addition, a systematic methodology for automotive interior sound field refinement
is also proposed on the basis of the modified PACA method. An example of a passenger car model demonstrates the application
of the sound-field-refinement methodology and shows the advantage of using damping layers at optimum locations on the auto
body. The example also shows that the modified PACA method has practical significance for refining the interior sound field
and decreasing added mass in accord with the trend towards lightweight auto bodies. 相似文献
998.
T. J. Kim H. Y. Kim B. C. Hwang H. J. Kang C. Kim 《International Journal of Automotive Technology》2009,10(5):611-618
There are three sub-processes associated with the assembly of an automobile transmission: heat fitting, shrink fitting, and
combination fitting. In the heat fitting stage, the gear is heated to a specified temperature and then squeezed towards the
outer diameter of the shaft. The stress of the heat-fitted gear depends on the yield strength of the gear. In the shrink fitting
process, the gear is typically squeezed towards the shaft at room temperature using a press. An alternate method, known as
warm shrink fitting, heats the already warm gear and safely squeezes it toward the shaft. The warm shrink fitting process
for automobile transmission parts is becoming more commonplace, but the additional heating can cause the dimensions of the
assembled parts (shaft/gear) to change with respect to both the outer diameter and the profile of the gear. As a result, there
may be additional noise and vibration between gears. To address these problems, we analyzed the warm shrink fitting process
using the contact pressure caused by fitting interference between the outer diameter of the shaft and the inner diameter of
the gear, fitting temperature, and the profile tolerance of the gear as design parameters. In this study, a closed form equation
for predicting the contact pressure and fitting load is proposed. This equation is used to develop an optimization technique
for the warm shrink fitting process. The reliability of the model was verified using experimental results measured in the
field, and FEM with thermal-structural coupled field analysis. Actual loads measured in the field showed good agreement with
the results obtained by theoretical and finite element analysis, and expansion of the outer diameters of the gears agreed
well with the results. 相似文献
999.
J. Kim N. Kim S. Hwang Y. Hori H. Kim 《International Journal of Automotive Technology》2009,10(6):733-742
A motor control strategy for an input-split hybrid electric vehicle (HEV) is proposed. From a power characteristic analysis,
it is found that the powertrain efficiency decreases for speed ratios at which power circulation occurs. Using dynamic models
of an input-split HEV powertrain, a motor-generator control algorithm for obtaining high system efficiency is designed by
inversion-based control. The performance of the control algorithm is evaluated by the simulator which is developed based on
PSAT, and simulation results are compared with the test results. It is found that, even if the engine thermal efficiency is
sacrificed by moving the engine operation point from the OOL for the control strategy, improved overall powertrain system
efficiency can be achieved by the engine operation that gives a relatively high efficiency from the viewpoint of the overall
powertrain efficiency. The control algorithm developed can be used in design of future electric vehicles. 相似文献
1000.
H. G. Jung Y. H. Lee H. J. Kang J. Kim 《International Journal of Automotive Technology》2009,10(2):219-228
This paper discusses the market trends and advantages of a safety system integrating LKS (Lane Keeping System) and ACC (Adaptive
Cruise Control), referred to as the LKS+ACC system, and proposes a method utilizing the range data from ACC for the sake of
lane detection. The overall structure of lane detection is the same as the conventional method using monocular vision: EDF
(Edge Distribution Function)-based initialization, sub-ROI (Region Of Interest) for left/right and distance-based layers,
steerable filter-based feature extraction, and model fitting in each sub-ROI. The proposed method adds only the system for
confining lane detection ROI to free space that is established by range data. Experimental results indicate that such a simple
adaptive ROI can overcome occlusion of lane markings and disturbance of neighboring vehicles. 相似文献