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121.
122.
In emulsion polymerization, the Smith and Ewart theory gives about two or three times the number of polymer particles obtained by experiment. In this paper, a reaction model is proposed which, from the standpoint of reactor design, can give an adequate explanation of the whole course of an emulsion polymerization of monomer highly insoluble in water. Among other things, the generating process of polymer particles is examined in detail. It is demonstrated experimentally that a new parameter proposed here, which represents the degree of difficulty of monomer initiation in micelles, is indispensable in explaining that process. Also confirmed is that monomer initiation takes place more easily in polymer particles than in micelles. According to the new model, the progress of polymerization, i.e., monomer conversion, the number of the polymer particles, and properties of polymer thus produced can be estimated with satisfactory accuracy. Furthermore, approximate equations are derived for easier estimation. 相似文献
123.
There is increasing demand for in situ shape measurements performed on ultraprecision processing machines. One major source of error during interferometric measurements performed on machines is fringe displacement due to external disturbances. We have developed an interferometer equipped with an electro-optic phase modulator that measures the phase of interference fringes before they are displaced by air turbulence. The frequency characteristics of air turbulence induced by a heat source are derived from successive measurements of a test surface. Experimental results show that the phase of the interference fringes can be accurately measured in the presence of air turbulence when the intensity of the fringes is sampled at a speed of several hundred hertz. 相似文献
124.
Monodispersed ellipsoidal hematite particles were synthesized and coated with silicone using a silane-coupling agent, phenyltriethoxysilane.
The thickness of the silicone shell was controlled by the concentration of phenyltriethoxysilane and the presence of n-hexadecyltrimethylammonium chloride, which was thought to modify the surface properties of the hematite particles to be organophilic.
The hematite/silicone core-shell particles were strongly hydrophobic and had a good dispersibility and stability in toluene.
Hollow ellipsoidal silicone particles were obtained by the dissolution of hematite with hydrochloric acid from the core-shell
particles. 相似文献
125.
Microscopic dissipation mechanism of quantized vortices in quantum fluid is studied numerically by solving the Gross-Pitaevskii
equation coupled with the Bogoliubov-de-Gennes equation for thermal excitations. At low temperatures, dissipation works at
smaller scales than the vortex core size, which supports the self-similar cascade process of quantized vortices at large scales
and the Kolmogorov energy spectrum of quantum turbulence. On the other hand, this dissipation spreads to larger scales at
high temperatures, and directly affects the vortex dynamics. This effect of dissipation at high temperatures is qualitatively
similar to the mutual friction in superfluid 4He. 相似文献
126.
Soft robotics is important in the next generation of robots because of the rapidly increasing need for robotics in biomedical applications and the advantages of providing a soft interface for interaction with the physical environment in service robots and other applications. It is indispensable to understand the fundamental behavior of such contact interface, typically viscoelastic, in order to accurately predict the actual elastic and temporal responses of the contact and to successfully control it. Viscoelasticity is a phenomenon of time-dependent strain and/or stress in soft materials. It is therefore important to model such behavior and to study the effects of such time-dependent strain and stress on stability and behavior at the contact interface. The contribution of this paper is the introduction of a novel latency model, which is a nonlinear model with differential equations that govern viscoelastic materials. Latency model describes various features of viscoelastic materials, such as stress relaxation and strain creep. The theoretical modeling was supported by experimental results in which we found two types of relaxation. Type I relaxation is well documented in existing literature but Type II relaxation has not been elaborated previously with the physical insights provided in this paper. The proposed theory can unify both types of time-dependent relaxation responses for modeling, sensing, and interpretation of viscoelastic contact interface. 相似文献
127.
Makoto Nikaido Toyokazu Kobayashi Tomio Ito Toshimitsu Higashi Hirofumi Tamura 《Advanced Robotics》2013,27(11-12):1229-1252
An analytic flow design algorithm for an automated distribution center with multiple shipping areas is presented. The main elements of the analytic flow design are the number of devices and the volumes of product flow between the devices. In the design of an automated distribution center, it is necessary to satisfy the demand throughput while minimizing construction costs. In the conventional design process, system engineers utilize experimental and intuitional approaches. However, conventional approaches are time-consuming and the design outcome is dependent on the skill of the designer. Therefore, a theoretical design algorithm is needed. We propose an analytic flow design algorithm using a dynamic network flow model and considering time-variable flow volumes according to shipment and storage schedules. To verify the feasibility of the proposed method, we perform analytic flow design using real data and confirm that the proposed method can yield a feasible analytic flow design in several minutes. 相似文献
128.
Nuclear magnetic resonance absorption spectra of linter cellulose containing various amounts of water were studied to clarify the relation between the amount of absorbed water in cellulose fiber and the molecular motion in such a cellulose–water system. An amorphous cellulose sample was used for the sake of comparison. The changes in line width and second moment of the spectra were measured at various temperatures. From the variation with temperature of the first-derivative curves and the second moments, it has been inferred that the proton movement of absorbed water changes markedly over the approximate range 180°–200°K and that the absorbed water lowers the glass transition temperature of cellulose to room temperature. 相似文献
129.
Scintillation properties of Tm-doped Lu3Al5O12 single crystals 总被引:1,自引:0,他引:1
Makoto Sugiyama Yutaka Fujimoto Takayuki Yanagida Daisuke Totsuka Yuui Yokota Akira Yoshikawa 《Optical Materials》2011,34(2):439-443
Using the micro-pulling-down (μ-PD) method, Tm-doped Lu3Al5O12 (Tm:LuAG) single crystals were grown to examine their scintillation properties. In transmittance spectra, they exhibited about 80% transparency in the wavelengths longer than 320 nm and five absorption lines due to Tm3+ 4f–4f transitions were observed. 241Am α-ray excited radioluminescence spectra were measured and intense 4f–4f emission peaks were observed with the host emission. When excited by 137Cs γ-Ray to obtain pulse height spectra, Tm 1% doped LuAG showed the highest light yield coupled with a photomultiplier (PMT) or a silicon avalanche photodiode (Si-APD). The light yield was estimated to be 5800 and 7300 photons/MeV for PMT and Si-APD, respectively. Decay time profiles consist of two exponential components and the fast and slow components are considered to be attributed to the host and the combination of the host and Tm3+ 4f–4f emission, respectively. 相似文献
130.
Majczak A Karbowski M Kamiński M Masaoka M Kurono C Niemczyk E Kedzior J Soji T Knap D Hallmann A Wakabayashi T 《Journal of electron microscopy》2004,53(6):635-647
Effects of jasplakinolide (JSP), a stabilizer of F-actin, and latrunculin A (LTA), a destabilizer of F-actin, on a series of events occurring in the execution phase of staurosporine (STS)-induced apoptotic processes were studied using human osteosarcoma 143B cells. Time-dependent apparent increases of the population of cells with collapsed membrane potential of mitochondria (Delta Psi(m)) caused by STS treatment were not due to actual decreases in the Delta Psi(m) per cell, but due to the fragmentation of cells resulting in decreases in the number of active mitochondria per cell. Decreases in the Delta Psi(m) in fragmented cells occurred late in the execution phase. Both JSP and LAT failed to prevent STS-induced release of cytochrome c from mitochondria followed by the activation of caspases 3 and 9, the cleavage of poly (ADP-ribose) polymerase (PARP) and apoptotic nuclear fragmentation. However, both drugs prevented STS-induced apoptotic cell fragmentation and decreases in the Delta Psi(m). These results indicate that physicochemical states of actin filaments play a certain role in the execution phase of STS-induced apoptotic processes. 相似文献