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691.
A recent survey reported that many commuter-cyclists had enjoyed leisure bicycling on a regular basis prior to becoming a
commuter-cyclist. While bicycling for leisure, it is assumed that they considered various factors that led them to consider
becoming commuter-cyclists. This study began with the question of how long it would take for a leisure-cyclist to become a
commuter-cyclist, and it focused on the time that elapsed between leisure-cyclists transitioning to commuter-cycling. In order
to analyze the time frame, it was hypothesized that the probability that a leisure-cyclist would become a commuter-cyclist
at a certain time would be conditional on the duration that elapsed from the onset of leisure cycling till that time, which
represents the “snowballing” or “inertial” dynamics of duration. A robust methodology, which is known as the “hazard model,”
was adopted to accommodate such characteristics of a time period. In addition, various external covariates such as individual-specific
characteristics, variables associated with the current or previous commuting mode, supply variables regarding bicycle facilities,
and individual latent propensities were adopted to account for the duration of changes that would be generally applicable.
As a result, many useful results were derived that could be used in fomenting policies to promote cycling to work. It was
found that government should invest in establishing segregated lanes for leisure- and commuter-cyclists. It also turned out
that a long distance to work hinders a leisure-cyclist from progressing to commuter-cycling. According to the results, young
white-collar workers who live in high-rise apartments and enjoy intensive leisure-cycling in groups, are a good target toward
whom promotions for commuter-cycling should be focused. However, an unfortunate development was that, when compared with car-commuters,
it was found that transit-commuters are more likely to become commuter-cyclists. 相似文献
692.
693.
This paper investigates the economic implications of the liberalization of air transportation across the Taiwan Strait to the region's aviation industries. Our analysis suggests that (1) liberalization has brought substantial benefits to airports and airlines in Mainland China and Taiwan. Negative impacts to Hong Kong are largely compensated by traffic increase in routes linking Mainland China. (2) In general, Taiwanese airports and airlines have benefited more from liberalization compared to airports and airlines on the mainland and Hong Kong. Such asymmetric effect is due to the larger size of the Mainland Chinese aviation market, which allows Taiwanese airlines to exploit network-related benefits. (3) Our investigation suggests that foreign hub carriers and medium sized Chinese airports will benefit most from China's future liberalizations. 相似文献
694.
695.
M.?Oguma Y.?J.?LeeEmail author S.?Goto 《International Journal of Automotive Technology》2012,13(1):33-41
Recently, biofuels have been actively introduced as transportation fuels in Asian countries. Common drivers to use biofuels
are energy security, fuel diversification, and the reduction of greenhouse gases. In addition, some Southeastern Asian countries
look forward to utilizing the abundant agricultural resources and providing stability for farmers. However, a compromised
quality of biofuels could cause vehicle trouble, which is why the quality standard of the fuels is very important. On the
other hand, the quality standard of biofuels differs from country to country and could cause vehicle trouble in some countries
and not others. These differing standards may become an obstacle to trade. In this situation, the harmonization of the biodiesel
standards in the East Asia Summit (EAS) region has been initiated by the ERIA biodiesel working group, in which members are
the specialists from each country. This review summarizes the introduction of biofuels in this region and the recent activities
regarding the harmonization of the fuel quality standard. Important background for this review is based on the results of
the ERIA biodiesel working group meeting. 相似文献
696.
A dynamic lumped-parameter gear model incorporating the effects of a time-varying and asymmetric mesh stiffness and a backlash nonlinearity is formulated to analyze the spur gear rattle response under the idling condition. The proposed theory assumes a rectangular time-varying mesh stiffness function. The phase shift between the mesh stiffness for forward and backward contacts is examined. Numerical studies are employed to examine the effects of engine torque fluctuations and tooth surface friction on the gear rattle response and the corresponding tooth impact behavior. Comparisons between the results from the time-invariant mesh stiffness model and the proposed time-varying mesh stiffness model reveal differences in the gear responses, especially when the mean rotational speed of the fluctuating gear pair is non-zero. The analysis reveals significant effects on the high frequency response components. However, the idling gear dynamics are relatively insensitive to tooth surface friction. 相似文献
697.
S. O. Kang S. O. Jun H. I. Park K. S. Song J. D. Kee K. H. Kim D. H. Lee 《International Journal of Automotive Technology》2012,13(4):583-592
This research aims to develop an actively translating rear diffuser device to reduce the aerodynamic drag experienced by passenger cars. One of the features of the device is that it is ordinarily hidden under the rear bumper but slips out backward only under high-speed driving conditions. In this study, a movable arc-shaped semi-diffuser device, round in form, is designed to maintain the streamlined automobile??s rear underbody configuration. The device is installed in the rear bumper section of a passenger car. Seven types of rear diffuser devices whose positions and protrusive lengths and widths are different (with the basic shape being identical) were installed, and Computational Fluid Dynamics (CFD) analyses were performed under moving ground and rotating wheel conditions. The main purpose of this study is to explain the aerodynamic drag reduction mechanism of a passenger car cruising at high speed via an actively translating rear diffuser device. The base pressure of the passenger car is increased by deploying the rear diffuser device, which then prevents the low-pressure air coming through the underbody from directly soaring up to the rear surface of the trunk. At the same time, the device generates a diffusing process that lowers the velocity but raises the pressure of the underbody flow, bringing about aerodynamic drag reduction. Finally, the automobile??s aerodynamic drag is reduced by an average of more than 4%, which helps to improve the constant speed fuel efficiency by approximately 2% at a range of driving speeds exceeding 70 km/h. 相似文献
698.
699.
H.?-Z.?Li L.?LiEmail author L.?He M.?-X.?Kang J.?Song L.?-Y.?Yu C.?Wu 《International Journal of Automotive Technology》2012,13(3):441-450
A Traction Control System (TCS) is used to control the driving force of an engine to prevent excessive slip when a vehicle
starts suddenly or accelerates. The torque control strategy determines the driving performance of the vehicle under various
drive-slip conditions. This paper presents a new torque control method for various drive-slip conditions involving abrupt
changes in the road friction. This method is based on a PID plus fuzzy logic controller for driving torque regulation, which
consists of a PID controller and a fuzzy logic controller. The PID controller is the fundamental component that calculates
the elementary torque for traction control. In addition, the fuzzy logic controller is the compensating component that compensates
for the abrupt change in the road friction. The simulation results and the experimental vehicle tests have validated that
the proposed controller is effective and robust. Compared with conventional PID controllers, the driving performance under
the proposed controller is greatly improved. 相似文献
700.
The intake system in an automotive engine has a short duct compared with that of the exhaust system. The filtered-x LMS (FX-LMS)
algorithm has been applied to the active noise control (ANC) system in a short acoustic duct. This algorithm design is based
on the FIR (finite impulse response) filter; however, it has a slow convergence issue due to a large number of zero coefficients.
To improve the convergence performance, the step size of the LMS algorithm was modified from fixed to variable. However, this
algorithm is still not suitable for the ANC system of a short acoustic duct because the reference signal is affected by the
backward acoustic wave propagated from a secondary source. Therefore, the recursive filtered-u LMS algorithm (FU-LMS) based
on the infinite impulse response (IIR) is developed to consider backward acoustic propagation. Generally, this algorithm has
a stability problem. The stability issue was improved using an error-smoothing filter. In this paper, the recursive LMS algorithm
with a variable step size and smoothing error filter is designed. This recursive LMS algorithm, the FU-VSSLMS algorithm, uses
an IIR filter. With fast convergence and good stability, this algorithm is suitable for the ANC system in a short acoustic
duct, such as the intake system of an automotive engine. This algorithm is applied to the ANC system of a short acoustic duct.
The disturbance signals used as primary noise source are a sinusoidal signal embedded in white noise and the chirp signal,
which has a variable instantaneous frequency. The test results demonstrate that the FU-VSSLMS algorithm has a superior convergence
performance when compared with the FX-LMS and FX-LMS algorithms. The algorithm can be successfully applied to the ANC system
in a short duct, such as the intake duct. 相似文献