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31.
Wei Wei Craig A. BennettRyuzo Tanaka Gang HouMichael T. Klein Jr. Michael T. Klein 《Fuel Processing Technology》2008
The complexity of many chemical and refining reaction systems and the thus-derived tedious and time-consuming process of building the associated kinetic models have been major obstacles in the use of fundamental kinetics in the solution of chemical engineering problems. This review summarizes work aimed at removing theses obstacles. Our recent work that has led to the enhancement of the Kinetic Modeler's Toolbox (KMT) and the development of the Kinetic Model Editor (KME) presents an end-to-end solution to the kinetic modeling process, including automated feedstock modeling, reaction network construction, kinetic rate estimation, model programming, process system configurations, model customizations, compilations, model execution and results analysis. 相似文献
32.
GI Kempen MJ van Heuvelen RH van den Brink AC Kooijman M Klein PJ Houx J Ormel 《Canadian Metallurgical Quarterly》1996,25(6):458-464
Molecular electrostatic potential (MEP) maps of certain 3-methoxy flavone derivatives having different anti-picornavirus activities have been studied. Geometries of the molecules were optimised and charge distributions computed using the AM1 molecular orbital method. Hybridization displacement charges (HDC) were combined with the L?wdin charge distributions to compute the MEP maps. Reliability of the method of computing MEP maps was tested by studying certain other molecules for which ab initio MEP results are available. The anti-picornavirus activities of the flavones have been shown to be related with negative MEP values in two regions, one near the 3-methoxy group and another in a diagonally opposite region near the substituent attached to the C7 atom of the molecules. 相似文献
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Utilitarian and economic theories of deterrence hold that the relation of the penalty to the misdeed should be irrelevant. In 5 experiments using hypothetical cases, judgments of penalties depended on whether this relation was in kind (IK) or out of kind (OK). When victims were identifiable, IK penalties were higher than OK and preferred to OK. Subjects seemed to confuse penalties and compensation. When there were no identifiable victims (e.g., environmental damage), IK penalties were preferred, but OK penalties were higher. Here, OK judgments were more uncertain, and subjects preferred to err on the side of overpunishing. The results can be explained in terms of overgeneralization of usually useful heuristics. Alternative hypotheses concerning aggression and scale compatibility are rejected. The findings have implications for the setting of penalties in legal cases (e.g., the Exxon Valdez) and for lay theories of punishment in nonlegal settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
35.
Delapasse J.S. Behbehani K. Kuangchung Tsui Klein K.W. 《IEEE transactions on bio-medical engineering》1994,41(11):1083-1091
A new self-tuning regulator for control of mean arterial blood pressure using sodium nitroprusside is presented. In addition to adapting to various patient response gains and time constants, the controller can accommodate variations in pure time delays, a problem that has not been addressed fully in previously proposed controllers. The control algorithm derivation is based on incorporating a self-turning controller with an adaptive discrete time delay compensator. The derivation, however, is general and can potentially be applied to other pharmacological agents in addition to sodium nitroprusside. The a priori information required for implementation of the controller is the estimate of the order of the patient response transfer function and the range of the pure time delay. An attractive feature of the controller is its capability to optimize the level of the infused drug during the transient phase of the control without creating an output offset. This feature tends to reduce the overall level of the infused drug. Hence, it may be useful when the cost of a drug or its long-term administration side effects is of concern, such as in the case of sodium nitroprusside 相似文献
36.
Thomas G. OConnor Jonathan A. Dantzig 《Metallurgical and Materials Transactions B》1994,25(3):443-457
A three-dimensional mathematical model has been developed to compute the thermomechanical state in the mold of thin-slab continuous
casters. The thin-slab mold differs from those used in conventional slab casters in that the upper portion of the broad side
walls defines a funnel-shaped chamber which allows the nozzle to be submerged into the liquid metal. The chamber converges
with distance down the mold, reducing to the rectangular cross section of the finished casting near the mold exit. The new
mold, along with casting speeds up to 6 m/min, allows slabs to be cast 50–60 mm thick, compared with 150 to 350 mm in conventional
continuous slab casting. However, the mold shape and high casting speed lead to higher mold temperatures and shorter mold
life than are found in conventional slab casters. In this article, we develop mathematical models of the process to determine
the role of various process parameters in determining the mold life. Finite-element analysis is used to determine the temperatures
in the mold and cast slab, and these data are then used in an elastic-viscoplastic analysis to investigate the deformation
of the mold wall in service. Cyclic inelastic strains up to 1.75 Pct are found in a region below the meniscus along the funnel
edge. These large strains result from the combination of locally high temperatures coupled with geometric restraint of the
mold. The deformation leads to short mold life because of thermal fatigue cracking of the mold. The computed locations and
time to failure of the mold in fatigue agree very well with observations of the appearance of mold surface cracks in an operating
caster. The models are also used to develop an improved mold design.
Formerly Research Assistant, Department of Mechanical and Industrial Engineering, University of Illinois, Urbana, IL 相似文献
37.
Both Soviet and American youth show a great concern about the possible effects of nuclear war, with heavy media users in both countries more optimistic, but the relation was stronger among Soviet students. 相似文献
38.
The paper presents a case study of the development of an expert decision support system which uses simple heuristic methods for fast determination of routes for simultaneous signals in a transmission network of limited capacity. It illustrates how heuristic solutions can be embodied in a model-based DSS and how the standard decision support literature, although intuitively appealing, provides little practical assistance in system construction or classification 相似文献
39.
Fast algorithms for single frequency estimation 总被引:2,自引:0,他引:2
In this paper, some new estimators of the frequency of a single complex sinusoid are presented. The rotate-add-decimate (RAD) method of Crozier is first refined to more closely approach the Cramer-Rao Bound (CRB). An additional modification yields an unbiased estimator (ERAD) that essentially achieves the CRB above a signal-to-noise ratio (SNR) threshold comparable to that of RAD. In addition, this estimator is proven to achieve the CRB for high SNR. The ERAD method requires approximately 2N complex multiply-adds and log/sub 2/N arctangents. A modified ERAD (MERAD) is proposed that matches the SNR threshold and computational complexity of the RAD method (approximately 3N complex multiply-adds and log/sub 2/N arctangents) but achieves the CRB for high SNR. 相似文献
40.