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81.
82.
In situ dynamic observations of the deformation and fracture characteristics of alpha/beta brass two-phase bicrystals were made by the solid diffusion method. The results indicated clearly that the crack initiation site was at the interface. The crack propagation direction, in both the alpha and beta phases, was found to be orientation dependent. Complementary experiments on alpha and beta brass single crystals confirmed the theories and results obtained previously on ductile single crystals.On leave from the Mechanical Engineering Department, Al-Azhar University, Cairo, Egypt. 相似文献
83.
Takayuki Kumada Shoji Mori Toshimitsu Nagasaka Jun Kumagai Tetsuo Miyazaki 《Journal of Low Temperature Physics》2001,122(3-4):265-277
The tunneling abstraction reaction: H+H2H2+H in -irradiated solid hydrogen has been studied using electron spin resonance (ESR) and electron-nuclear double resonance (ENDOR) spectroscopy and gas-chromatography. The rate constant for the tunneling reaction in solid hydrogen was found to decrease with the increase in the concentration of ortho-H2 molecules in solid hydrogen. We concluded that the decrease in the rate constant is due to the energy level mismatching between reactant species of H+H2 trapped and product species of H2+H trapped in the reverse induced by inhomogeneous intermolecular interactions between ortho-H2 molecules in solid hydrogen. This result indicates that resonance effects play an important role in tunneling reactions in solids. 相似文献
84.
Novel vitamin E derivative with 4-substituted resorcinol moiety has both antioxidant and tyrosinase inhibitory properties 总被引:3,自引:0,他引:3
A novel vitamin E derivative, (6″-hydroxy-2″,5″,7″,8″-tetramethylchroman-2″-yl) methyl 3-(2′,4′-dihydroxyphenyl)propionate
(TM4R), which has a chromanoxyl ring and 4-substituted resorcinol moieties, was synthesized; and its inhibitory effects on
tyrosinase, antioxidant ability, and lightening effect of ultraviolet B (UVB)-induced hyperpigmentation were estimated. TM4R
showed potent inhibitory activity on tyrosinase, which is the rate-limiting enzyme in melanogenesis. The scavenging activities
of TM4R on 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radicals were found to be nearly the same as those of α-tocopherol.
Furthermore, an efficient lightening effect was observed following topical application of TM4R to UVB-stimulated hyperpigmented
dorsal skin of brownish guinea pigs. These results suggest that TM4R may be a candidate for an efficient whitening agent,
possibly by inhibiting tyrosinase activity and biological reactions caused by reactive oxygen species. 相似文献
85.
We propose a new algorithm for routing packets which effectively avoids packet congestion in computer networks. The algorithm
involves chaotic neurodynamics. To realize effective packet routing, we first composed a basic method by a neural network,
which routes packets with shortest path information between two nodes in the computer network. When the computer network has
an irregular topology, the basic routing method does not work well, because most of packets cannot be transmitted to their
destinations due to packet congestion in the computer network. To avoid such an undesirable problem, we employed chaotic neurodynamics
to extend the basic method. Numerical experiments show that our proposed method exhibits good performance for scale-free networks.
We also analyze why the proposed routing method is effective, comparing the proposed method with several stochastic methods.
We introduced the method of surrogate data, a statistical hypothesis testing which is often used in the field of nonlinear
time-series analysis. Analysis of the proposed method by the method of surrogate data reveals that the chaotic neurodynamics
is most effective to decentralize the packet congestion in the computer network. 相似文献
86.
The removal of paint on the surface of waste plastics is difficult by the conventional process; in this research, a new cleaning mechanism using atmospheric plasmas was examined through optical emission spectroscopy, electron spectroscopy for chemical analysis, and scanning electron microscopy. Results indicate that an increase of pulse frequency enables for a short processing time for the removal of the paint film, signifying that the production of radicals in plasma, especially oxygen radicals, can be controlled by pulse frequency.Plasma jets were generated under the experimental conditions of an input power of 250 W to 400 W, a pulse frequency of 2 kHz to 12 kHz, and a plasma gas flow rate of 30 L/min. Examination of the intensity ratio of the reactive species, as measured by emission spectroscopy, showed that the O/N value increased with an increase in pulse frequency. Results of analysis with electron spectroscopy for chemical analysis show that nitrogen atoms and molybdenum in only the paint film decreased through plasma processing. 相似文献
87.
Hiroyuki Hirakata Yoshimasa Takahashi Do Van Truong Takayuki Kitamura 《International Journal of Fracture》2007,145(4):261-271
In order to elucidate the role of plasticity on interface crack initiation from a free edge and crack propagation in a nano-component,
delamination experiments were conducted by a proposed nano-cantilever bend method using a specimen consisting of ductile Cu
and brittle Si and by a modified four-point bend method. The stress fields along the Cu/Si interface at the critical loads
of crack initiation and crack propagation were analyzed by the finite element method. The results reveal that intensified
elastic stresses in the vicinity of the interface edge and the crack tip are very different, although the Cu/Si interface
is identical in both experiments. The plasticity of Cu was then estimated on the basis of the nano-cantilever deflection measured
by in situ transmission electron microscopy. The plasticity affects the stress fields; the normal stress near the interface
edge is intensified while that near the crack tip is much reduced. Both the elasto-plastic stresses are close to each other
in the region of about 10 nm. This suggests that the local interface fracture, namely, the crack initiation at the interface
edge and the crack propagation along the interface, is governed by elasto-plastic normal stress on the order of 10 nm. 相似文献
88.
Takayuki Ueki Akifumi Yoshihara Yuji Teramura 《Science and Technology of Advanced Materials》2016,17(1):807-815
Since circulating tumor cells (CTCs) are tumor cells which are found in the blood of cancer patients, CTCs are potential tumor markers, so a rapid isolation of CTCs is desirable for clinical applications. In this paper, a three-dimensional polystyrene (PS) microfiber fabric with vacuum aspiration system was developed for capturing CTCs within a short time. Various microfiber fabrics with different diameters were prepared by the electrospinning method and optimized for contact frequency with cells. Vacuum aspiration utilizing these microfiber fabrics could filter all cells within seconds without mechanical damage. The microfiber fabric with immobilized anti-EpCAM antibodies was able to specifically capture MCF-7 cells that express EpCAM on their surfaces. The specificity of the system was confirmed by monitoring the ability to isolate MCF-7 cells from a mixture containing CCRF-CEM cells that do not express EpCAM. Furthermore, the selective capture ability of the microfiber was retained even when the microfiber was exposed to the whole blood of pigs spiked with MCF-7 cells. The specific cell capture ratio of the vacuum aspiration system utilizing microfiber fabric could be improved by increasing the thickness of the microfiber fabric through electrospinning time. 相似文献
89.
Kimihiro Yamanaka Takafumi Ooyoshi Takayuki Nejime 《Journal of Materials Science: Materials in Electronics》2010,21(1):53-57
Measuring the real temperature of a flip chip solder joint during an electromigration test has been a problem because of its
small size and the local Joule heating due to a large applied current. A unique method that employs the electrical resistance
change in the junction line between two solder joints was introduced to determine the temperature of the solder joint. The
change in resistance was converted into temperature using a thermal coefficient of resistance of the junction line. The method
accurately measured temperatures of the solder joint within 2 K until the solder joint resistance change ratio reached 100%
due to growth of an electromigration void. 相似文献
90.
Takayuki Wada Author Vitae Author Vitae 《Automatica》2010,46(8):1339-1345
Efficient randomized algorithms are developed for solving robust feasibility problems with multiple parameter-dependent convex constraints. Two complementary strategies are presented, both of which exploit the multiplicity to achieve fast convergence. One is the stochastic ellipsoid method with multiple updates. In each iteration of this algorithm, an ellipsoid which describes a candidate of the solution set is updated many times via the multiple constraints with one random sample, while at most one update is allowed in the original method. The other is the stochastic ellipsoid method with multiple cuts. Here, a new update rule is presented to construct a smaller ellipsoid directly via multiple subgradients given by the constraints. A quantitative analysis of the volume of the ellipsoid is also provided, which guarantees the advantage of the proposed algorithm over the original one. The above features lead to a reduction of the total number of random samples necessary for convergence, which is extensively demonstrated through numerical examples. 相似文献