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321.
S Kobayashi E Imai H Tachibana T Fujiwara T Takeuchi 《Canadian Metallurgical Quarterly》1998,45(2):3S-8S
Four isolates of Entamoeba dispar identified by their hexokinase and phosphoglucomutase isoenzyme profile and by their failure to react with Entamoeba histolytica-specific monoclonal antibody (4G6) could be grown in either Diamond's BI-S-33 medium, newly developed BCSI-S (Biosate cysteine starch iron-serum) medium, or casein-free YI-S medium in the presence of Crithidia fasciculata (ReF-1:PRR) sterilized by heating 56 degrees C for 30 min and subsequent incubation with 1% hydrogen peroxide for 24 hours at 4 degrees C. After the cultures were maintained for over 50 passages, the amebae were identified as E. dispar by isoenzyme analysis, polymerase chain reaction with E. histolytica- and E. dispar-specific primers, i.e. p11 plus p12 and p13 plus p14, respectively, and by negative reactivity with monoclonal antibody 4G6. The flagellates added to the culture were judged to be metabolically inactive based on the results of nuclear magnetic resonance spectroscopy, electron microscopy, and polarographic analysis. All of these findings suggest that E. dispar can grow in vitro with metabolically inactive C. fasciculata as a culture associate. 相似文献
322.
K Miki K Iwata Y Tsuboi R Sumino T Fukuoka T Tachibana A Tokunaga K Noguchi 《Canadian Metallurgical Quarterly》1998,76(3):407-415
During nerve cell degeneration, cholesterol released from the degrading cells is conserved through the formation of a cholesterol-apolipoprotein (apo) E complex which is subsequently taken up by regenerating nerve cells. The aim of the present project was to identify the physiologically relevant lipoprotein receptor for this lipoprotein complex which has remained elusive. HDL was separated into apo E-rich and apo E-poor subfractions and labelled with [14C]-sucrose. Labelled apo E-rich HDL bound to rat brain membranes in a time- and ligand concentration-dependent manner and was a saturable process. Essentially no binding occurred with [14C]-apo E-poor HDL or with free apo E. Binding was partially inhibited by low density lipoprotein (LDL) and by alpha 2-macroglobulin. These results provide new evidence that native apoE-rich HDL particles resembling those present in the brain bind to rat brain membranes and that the binding may be due, at least in part, to the LDL receptor and to the LDL-receptor related protein. Evidence was also provided for the presence of a receptor which binds [14C]-sucrose human apoE-rich HDL in human brain. Characterisation of the receptor which mediates the uptake of cholesterol from HDL-like complexes by brain cells is important in understanding the role of apoE in the central nervous system and of the alterations which occur in disorders such as Alzheimer's disease. 相似文献
323.
324.
Repeated temperature modulation epitaxy for p-type doping and light-emitting diode based on ZnO. 总被引:27,自引:0,他引:27
Atsushi Tsukazaki Akira Ohtomo Takeyoshi Onuma Makoto Ohtani Takayuki Makino Masatomo Sumiya Keita Ohtani Shigefusa F Chichibu Syunrou Fuke Yusaburou Segawa Hideo Ohno Hideomi Koinuma Masashi Kawasaki 《Nature materials》2005,4(1):42-46
Since the successful demonstration of a blue light-emitting diode (LED), potential materials for making short-wavelength LEDs and diode lasers have been attracting increasing interest as the demands for display, illumination and information storage grow. Zinc oxide has substantial advantages including large exciton binding energy, as demonstrated by efficient excitonic lasing on optical excitation. Several groups have postulated the use of p-type ZnO doped with nitrogen, arsenic or phosphorus, and even p-n junctions. However, the choice of dopant and growth technique remains controversial and the reliability of p-type ZnO is still under debate. If ZnO is ever to produce long-lasting and robust devices, the quality of epitaxial layers has to be improved as has been the protocol in other compound semiconductors. Here we report high-quality undoped films with electron mobility exceeding that in the bulk. We have used a new technique to fabricate p-type ZnO reproducibly. Violet electroluminescence from homostructural p-i-n junctions is demonstrated at room-temperature. 相似文献
325.
326.
The key words for the future telecommunications are personalization, multi-media services and high accessibility to the network. These trends naturally lead to radio media application to access links. In this sense, this paper proposes an advanced wireless access system with a capacity supporting broadband video and data services.Concept of the system can be defined as a new radiocommunication category with advantages of both fixed and mobile systems.The system is designed to transport ATM-based signals using SHF (or EHF) bands to wireless terminals, interconnected with optical fibers at the network side. The basic system configuration is presented as well as examples of system parameters.For radio aspects the maximum service coverages of the radio base stations are calculated based on availability consideration. Preferred frequency bands for actual operation are also discussed. 相似文献
327.
The authors describe the relationship between the resistance of a development roller and the development characteristics of a monocomponent development system. To investigate this relationship the authors developed an electric field neutralization model by considering a virtual electrode determined by the time constant of a resistive layer on a development roller. From a simulation model and experimental results, the authors find that the tone reproduction curve for development γ is strongly dependent on the layer time constant. When the time constant is smaller than the development time, γ is determined by neutralization of the development electric field. When the time constant is larger than the development time, γ is determined by a counter charge left on the development roller after toner is deposited on the photoreceptor. It became possible to vary the tone curve over a wide range by the time constant of development roller in monocomponent development 相似文献
328.
A biped walking robot capable of moving on a vertical wall 总被引:6,自引:0,他引:6
Akira Nishi 《Mechatronics》1992,2(6):543-554
The use of a wall-climbing robot for purposes such as rescue, wall inspection and fire-fighting on high-rise buildings has been anticipated for a long time. Three different types of wall-climbing robots have been developed in Japan. The first one has a large area sucker, which has the reverse mechanism of a hovercraft. This type can be used only on flat and wide surfaces. The second one has crawlers to move on a vertical wall with many small suckers on them. The third one has a walking mechanism with small suckers on each foot. A biped walking model was built and tested on a vertical wall and a ceiling. The aerodynamic matching between blower performance and required forces of a sucker, as well as the control systems of the robot, are studied in detail. 相似文献
329.
Makoto Murakami Ken-ichi Suzuki Hideki Maeda Tetsuo Takahashi Akira Naka Norio Ohkawa Mamoru Aiki 《Optical Fiber Technology》1997,3(4):320-338
Optical amplifier techniques have led to the installation of large-capacity submarine systems and further capacity increases seem likely. This paper reviews the FSA submarine system, which flexibly operates at both 2.5 and 10 Gb/s and offers maximum transmission capacity of 60 Gb/s for commercial use. The system configuration as well as its characteristics and upgradability will be introduced, including measurement results on time-division-multiplexing/wavelength-division-multiplexing (TDM–WDM) transmission at bit rates of 10 and 20 Gb/s using non-return-to-zero or soliton pulses. To further increase transmission capacity, TDM–WDM techniques that permit more than 10 Gb/s signal transmission in each data channel should be developed. Thus, pulse formats, which include non-return-to-zero, return-to-zero, or soliton pulses, and dispersion allocation in transmission fibers are significant issues. We introduce and discuss our recent results from high-speed (10 to 40 Gb/s) TDM–WDM signal transmission experiments with regard to the above aspects. 相似文献
330.
Akira Okada 《Journal of Materials Science》1990,25(9):3901-3905
Diametral compression tests were carried out for unidirectionally aligned silicon carbide fibrereinforced borosilicate glass. The fracture load dependence on the angle between the loading axis and the fibre alignment was investigated. The stress components in the fibre-aligned plane were calculated to evaluate the effect of the shear stress on fracture. Weibull statistics were employed to estimate the fracture load dependence on the fibre orientation angle. Assumingm = 5 to 10, the contribution of shear stress to the fracture of silicon carbide fibrereinforced glass was found to be negligible. 相似文献