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51.
Hans-Hermann Rüttinger Hermann Matschiner Werner Schroth 《Advanced Synthesis \u0026amp; Catalysis》1979,321(2):274-278
Polarographic Investigations of 1,3-Thiazinthiones 1,3-Thiazine-6-thiones are stepwise reduced in aprotic media to the corresponding radical anions and dianions. In the case of the 2,4-diphenyl derivative ( 1a ) the radical anion is stable in dimethylformamide, whereas the dianion reacts further to yield the bithiazinylidene ( 4 ) among other products. The effect of substituents on the reduction potentials is discussed. 相似文献
52.
Hypermedia systems have been implemented for such a wide range of applications that one must wonder whether their principles should not be included among the building blocks of computer environments themselves. In this paper, we argue that this would indeed be desirable and present a model on which such extension could be based.After a brief review of hypermedia principles and the terminology used in this paper, we give examples of several computer applications in which hypermedia already are or could advantageously be used. We then suggest that most computer applications would greatly benefit if hypermedia were extended from isolated applications to a system-wide facility and that this could substantially simplify implementation of new hypermedia applications. This claim is then generalized and it is shown that extending hypermedia concepts to the organization of the computer environment itself --- the file system --- and to the user interface would make computer environments more flexible and easier to use.We then list the main characteristics of such a ‘hyperenvironment’ and conclude the paper with an outline of its implementation model and an example. 相似文献
53.
54.
The unique properties of gold nanoparticles have stimulated the increasing interest in the application of GNPs in interfacing
biological recognition events with signal transduction and in designing biosensing devices exhibiting novel functions. The
optical properties of GNPs provide wide range opportunities for construction optical biosensors. The excellent biocompatibility,
conductivity, catalytic properties and high surface-to-volume ratio and high density of GNPs facilitate extensive application
of GNPs in construction of electrochemical and piezoelectric biosensors with enhanced analytical performance with respect
to other biosensor designs. In this article, the recent advances in construction of GNP-based optical, electrochemical and
piezoelectric biosensors are reviewed, and some illustrative examples given, with a focus on the roles GNPs play in the biosensing
process and the mechanism of GNPs for improving the analytical performances. Finally, the review concludes with an outline
of present and future research for the real-world applications. 相似文献
55.
Tibor Goda Káeroly Váradi Klaus Friedrich Hermann Giertzsch 《Journal of Materials Science》2002,37(8):1575-1583
FE micro-models have been developed in order to determine contact, stress and strain conditions produced by a steel asperity sliding on the surface of a normally oriented fibre-reinforced polymer composite. A displacement coupling technique was introduced to model a micro-environment as part of a macro-environment and to get more realistic simulation results about the failure conditions in the composite structure, in comparison to the so far widely applied anisotropic analytical or numerical macro-models. On the basis of the results, conclusions may be drawn for the possible wear mechanisms of the fibre-reinforced polymer composite. Stress results in the vicinity of the fibers in the contact area show high shear loading of the matrix leading to the formation of stretched-out matrix wear debris. In addition, high repeated compression-tension stresses at the fibre/matrix interface near the surface can lead to fibre debonding phenomena. Considering the fibre ends in the contact region, high compression stresses at their rear edges can produce fibre cracking features. To study the wear mechanisms experimentally, a single asperity scratch test was also performed showing shear failure events of the polymer matrix, fibre/matrix debonding and fibre cracking effects, as expected from the modelling studies. 相似文献
56.
Chen Edith; Hermann Cathy; Rodgers Denise; Oliver-Welker Tina; Strunk Robert C. 《Canadian Metallurgical Quarterly》2006,25(3):389
This study tested the relationship of anxiety and asthma severity to symptom perception. Eighty-six children diagnosed with mild or moderate asthma had symptom perception and pulmonary function measured throughout methacholine challenge (to induce bronchoconstriction). Higher trait anxiety was associated with heightened symptom perception (controlling for pulmonary function) at baseline. Greater asthma severity was associated with blunted symptom perception (controlling for pulmonary function) at the end of methacholine challenge and with a slower rate of increase in symptom perception across methacholine challenge. These results suggest that anxiety plays a role when children's symptoms are mild, whereas medical variables such as severity play a role in perception of changes in asthma symptomatology as bronchoconstriction worsens. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
57.
Photonic crystals with a complete bandgap can stop the propagation of light of a certain frequency in all directions. We introduce double‐inverse‐opal photonic crystals (DIOPCs) as a new kind of optical switch. In the DIOPC, a movable, weakly scattering sphere is embedded within each pore of the inverse‐opal photonic crystal lattice. Switching between a diffusive reflector and a photonic crystal environment is experimentally demonstrated. Theory shows that a complete bandgap can be realized that can be opened or closed by moving the spheres. This functionality opens up new possibilities for the control of light emission and propagation. The close link and interaction between the chemical synthesis and the computational design and analysis underlines the interdisciplinary focus of this report. 相似文献
58.
Seidenberg Michael; Hermann Bruce; Wyler Allen R.; Davies Keith; Dohan F. Curtis Jr.; Leveroni Catherine 《Canadian Metallurgical Quarterly》1998,12(2):303
The nature, pattern, and degree of neuropsychological change following anterior temporal lobectomy (ATL) were examined as a function of the presence or absence of the syndrome of mesial temporal lobe epilepsy (MTLE). Fifty-four patients exhibited the syndrome of MTLE, while 34 patients were without the syndrome (non-MTLE). The test-retest performance of a group of 40 epilepsy patients who did not undergo surgery was used to derive regression based estimates of test-retest change. Overall, the MTLE group did not show significant cognitive decline following ATL. In contrast, the left non-MTLE group showed significant declines on verbal memory, confrontation naming, and verbal conceptual ability. Further, verbal memory was the most substantial area of decline, and was independent of seizure outcome. Clinical and theoretical implications of these findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
59.
60.
The refractory metals Nb, Ta, Mo, and W dissolve C, N, and O by forming interstitial solid solutions. The concentration of
these components can be increased or decreased by annealing treatments, depending on the partial pressure of gases such as
N2, O2, H2O, CH4, or CO and on the temperature of the specimen. New results in binary and ternary systems combined with those obtained in
the last few years now provide most of the data needed for the thermochemical analysis of the solid solution phases and for
the establishment of p-T-c phase diagrams. The mechanisms of the gas-metal reactions and the general feature of the constitution
diagrams are similar for all refractory metals. However, marked differences exist between group Va metals niobium and tantalum
and group VIa metals molybdenum and tungsten in the absolute values and temperature dependence of the equilibrium pressure
of gaseous species and therefore also in the amount of gas absorbed. The data now available for the estimation of the final
content of interstitials in solid solution after annealing treatments are compiled and discussed.
On leave from the Max-Planck-Institut fur Metallforschung, Institut fur Sondermetalle, Stuttgart, Germany 相似文献