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排序方式: 共有513条查询结果,搜索用时 15 毫秒
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I analyze the determinants of the stated capital cost of IPPs' power projects which significantly influences their price of power. I show that IPPs face a strong incentive to overstate their capital cost and argue that effective competition or regulatory scrutiny will limit the extent of the same. I analyze the stated capital costs of combined cycle gas turbine (CCGT) IPP projects in eight developing countries which became operational during 1990–2006 and find that the stated capital cost of projects selected without competitive bidding is 44–56% higher than those selected with competitive bidding, even after controlling for the effect of cost differences among projects. The extent to which the stated capital costs of projects selected without competitive bidding are higher compared those selected with competitive bidding, is a lower bound on the extent to which they are overstated. My results indicate the drawbacks associated with a policy of promoting private sector participation without an adequate focus on improving competition or regulation. 相似文献
44.
Anindita Bhadra Aniruddha Mitra Sujata A. Deshpande Kannepalli Chandrasekhar Dattatraya G. Naik Abraham Hefetz Raghavendra Gadagkar 《Journal of chemical ecology》2010,36(4):424-431
Queens and workers are not morphologically differentiated in the primitively eusocial wasp, Ropalidia marginata. Upon removal of the queen, one of the workers becomes extremely aggressive, but immediately drops her aggression if the
queen is returned. If the queen is not returned, this hyper-aggressive individual, the potential queen (PQ), will develop
her ovaries, lose her hyper-aggression, and become the next colony queen. Because of the non-aggressive nature of the queen,
and because the PQ loses her aggression by the time she starts laying eggs, we hypothesized that regulation of worker reproduction
in R. marginata is mediated by pheromones rather than by physical aggression. Based on the immediate loss of aggression by the PQ upon return
of the queen, we developed a bioassay to test whether the queen’s Dufour’s gland is, at least, one of the sources of the queen
pheromone. Macerates of the queen’s Dufour’s gland, but not that of the worker’s Dufour’s gland, mimic the queen in making
the PQ decrease her aggression. We also correctly distinguished queens and workers of R. marginata nests by a discriminant function analysis based on the chemical composition of their respective Dufour’s glands. 相似文献
45.
Sara Alcorn Amanda J. Walker Nishant Gandhi Amol Narang Aaron T. Wild Russell K. Hales Joseph M. Herman Danny Y. Song Theodore L. DeWeese Emmanuel S. Antonarakis Phuoc T. Tran 《International journal of molecular sciences》2013,14(7):14800-14832
As our understanding of the molecular pathways driving tumorigenesis improves and more druggable targets are identified, we have witnessed a concomitant increase in the development and production of novel molecularly targeted agents. Radiotherapy is commonly used in the treatment of various malignancies with a prominent role in the care of prostate cancer patients, and efforts to improve the therapeutic ratio of radiation by technologic and pharmacologic means have led to important advances in cancer care. One promising approach is to combine molecularly targeted systemic agents with radiotherapy to improve tumor response rates and likelihood of durable control. This review first explores the limitations of preclinical studies as well as barriers to successful implementation of clinical trials with radiosensitizers. Special considerations related to and recommendations for the design of preclinical studies and clinical trials involving molecularly targeted agents combined with radiotherapy are provided. We then apply these concepts by reviewing a representative set of targeted therapies that show promise as radiosensitizers in the treatment of prostate cancer. 相似文献
46.
Fine-grained ceramics (with a grain size on the order of a micron) have been produced by the spark plasma sintering (SPS) of various alumina nanopowders. We have compared the microhardness of ceramic samples prepared from 11 alumina nanopowders and that of composites based on such powders. The ceramics have been prepared by both SPS and a conventional technique (sequential pressing and sintering). We examine the effect of the phase composition and average particle size of the starting nanopowder on the microhardness of the ceramics. 相似文献
47.
S.S. Kalagi S.S. Mali D.S. Dalavi A.I. Inamdar Hyunsik Im P.S. Patil 《Synthetic Metals》2011,161(11-12):1105-1112
Inorganic tungsten oxide (WO3) and organic polyaniline (PANI) films were used as the cathodic and anodic electrodes of an inorganic–organic electrochromic device (IOECD). WO3 was deposited by sputtering while PANI films were electrodeposited on transparent Indium doped Tin Oxide (ITO) glass substrates, respectively. Optical and electrochemical studies were performed to find the optical attenuation, coloration efficiencies, reversibility and response time separately for the individual films as well as for the assembled IOECD. The change in transmittance of WO3 film was found to be 63.92%. PANI film showed an optical attenuation of 50.69% while the transmission change through the IOECD was equal to 57%. Colorimetric analysis was done to define the colors in the bleached and colored states in terms of L*ab values and xy chromaticity diagram. Factors limiting the performance of an IOECD were analyzed. It was found that in a charge unbalanced dual complementary IOECD, the coloration efficiency is always less than that of one of the constituent electrodes. 相似文献
48.
Dhananjay Joshi Pradeep Mahadevan Amol Marathe Anindya Chatterjee 《International Journal of Pressure Vessels and Piping》2007
Gasketless flanged joints with metal to metal contact offer some advantages over gasketed joints such as lower weight and better fatigue life. Design of such joints is often based on finite element analyses, and complicated by the fact that the area of contact between the flanges changes upon application of loads. Such analyses can be done using commercial software, which can incorporate geometrical nonlinearities as well as contact nonlinearities. Engineering intuition suggests that the role of geometrical nonlinearities might be small for such problems. However, many engineers continue to use the fully nonlinear analyses. Our aim in this paper is simply to put on record that significant savings in time can be obtained by “turning off” geometric nonlinearities in such analyses, with negligible loss of accuracy. To this end, a nonautomated implementation of the basic ideas is first demonstrated for a simple geometry; more automated analyses for a more general geometry follow. 相似文献
49.
Amol Singh N. K. Mehta P. K. Jain 《The International Journal of Advanced Manufacturing Technology》2007,34(9-10):988-1007
For most shop floors, consideration of more than one criterion would be likely to provide more realistic scheduling of a given set of jobs. The present paper considers this aspect of scheduling and uses an algorithm proposed by the authors in their previous work for implementing several criteria simultaneously in a shop of dynamic nature. The algorithm considers several dispatching rules simultaneously for selecting a job for processing and continuously monitors the attained values of performance measures. The selection of dispatching rules is made by identifying the worst performing criterion. A rule that can improve system performance for the worst-performing criterion is selected to dispatch the part under consideration. In this paper, several case studies have been attempted to evaluate the efficiency of the algorithm. The results of the taken case studies indicate that in a dynamic system the system performance improves by changing the dispatching rules corresponding to the worst-performance criterion at the appropriate deterioration in the performance measures. 相似文献
50.