全文获取类型
收费全文 | 91826篇 |
免费 | 2194篇 |
国内免费 | 326篇 |
专业分类
电工技术 | 1490篇 |
综合类 | 256篇 |
化学工业 | 14166篇 |
金属工艺 | 3088篇 |
机械仪表 | 2008篇 |
建筑科学 | 4317篇 |
矿业工程 | 956篇 |
能源动力 | 5836篇 |
轻工业 | 8880篇 |
水利工程 | 1707篇 |
石油天然气 | 827篇 |
武器工业 | 2篇 |
无线电 | 7298篇 |
一般工业技术 | 12378篇 |
冶金工业 | 11831篇 |
原子能技术 | 975篇 |
自动化技术 | 18331篇 |
出版年
2023年 | 923篇 |
2022年 | 956篇 |
2021年 | 1436篇 |
2020年 | 1570篇 |
2019年 | 1459篇 |
2018年 | 1777篇 |
2017年 | 2630篇 |
2016年 | 2931篇 |
2015年 | 2240篇 |
2014年 | 3425篇 |
2013年 | 5902篇 |
2012年 | 3117篇 |
2011年 | 4276篇 |
2010年 | 3791篇 |
2009年 | 4045篇 |
2008年 | 3295篇 |
2007年 | 3671篇 |
2006年 | 3593篇 |
2005年 | 3098篇 |
2004年 | 2558篇 |
2003年 | 2497篇 |
2002年 | 2054篇 |
2001年 | 1661篇 |
2000年 | 1381篇 |
1999年 | 1747篇 |
1998年 | 4326篇 |
1997年 | 2629篇 |
1996年 | 2009篇 |
1995年 | 1333篇 |
1994年 | 1279篇 |
1993年 | 1386篇 |
1992年 | 890篇 |
1991年 | 801篇 |
1990年 | 708篇 |
1989年 | 672篇 |
1988年 | 796篇 |
1987年 | 1195篇 |
1986年 | 1070篇 |
1985年 | 923篇 |
1984年 | 959篇 |
1983年 | 675篇 |
1982年 | 644篇 |
1981年 | 626篇 |
1980年 | 580篇 |
1979年 | 621篇 |
1978年 | 597篇 |
1977年 | 479篇 |
1976年 | 487篇 |
1974年 | 400篇 |
1973年 | 443篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
61.
62.
V. P. Shmerko 《Automation and Remote Control》2004,65(6):893-912
Theoretical results due to V. Malyugin on linearization of arithmetical models of logical functions are interpreted and refined from the viewpoint of modern techniques of logical design of integral circuits and nearest neighbor technologies. 相似文献
63.
64.
Theoretical and experimetal methods have been developed to characterize the effect of mechanical loading on the mesoscopic
and macroscopic mechanical state of polycrystalline materials. Ferritic and austenitic single-phase materials were first analyzed,
then phase interaction was studied in a multiductile phase material (austeno-ferritic duplex steel) and a natural reinforced
composite (pearlitic steel). The theoretical method is based on the self-consistent approach in which elastic and plastic
characteristics of the phases have been applied through the micromechanical behavior of single-crystal-using slip systems
and microscopic hardening. The effects of a crystallographic texture and phase interaction during loading and after unloading
were studied. The elastic and plastic anisotropy of the grains having the same crystallographic orientation were assessed
by diffraction strain analysis. The simulation was compared with the experiments performed using the X-ray diffraction technique.
In the considered duplex and pearlitic steels, it was observed that the ferrite stress state is much lower than the austenite
and cementite ones. The results of diffraction strain distribution have showed the pertinence of the models and give valuable
information, for example, for the yield stress and the hardening parameters of each phase in a two-phase material. 相似文献
65.
Interfacial hybridization kinetics of oligonucleotides immobilized onto fused silica surfaces 总被引:3,自引:0,他引:3
Jiang Zeng Amer Almadidy James Watterson Ulrich J. Krull 《Sensors and actuators. B, Chemical》2003,90(1-3):68-75
Fused silica optical fibers have been used in an intrinsic mode optical configuration as biosensors for fluorescence based detection of hybridization of nucleic acids. In this work, the kinetics of hybridization of single-stranded oligonucleotides that were covalently immobilized were studied. The probe DNA was dT20, and the target was Fluorescein-labeled non-complementary (dT20) or complementary (dA20) oligonucleotide. Chronofluorimetric monitoring of the adsorption and hybridization processes was used to investigate oligonucleotide films of different density, in different salt concentrations, at temperatures of 25 and 40 °C, with the concentration of the target DNA being 0.005–0.1 μM. Mathematical models based on first- and second-order Langmuir adsorption have been examined to describe both the adsorption and the hybridization processes. Experimental data were processed using the models, and the hybridization kinetics were calculated. Hybridization kinetics on these optical fiber DNA sensors was found to be up to three orders faster than results presented for a number of other experiments using different immobilization chemistries. 相似文献
66.
Electrophoretic deposition of electrolyte materials for solid oxide fuel cells, including La0.8Sr0.2Ga0.875Mg0.125O3–x
, yttria stabilized zirconia and (Ce0.8Gd0.2)O1.9, was studied under various experimental conditions. The use of phosphate ester as a dispersant and poly (vinyl butyral) as a binder enabled high deposition rate and formation of crack-free, adherent deposits. Electrodeposition rates were quantified in experiments performed at constant current and constant voltage modes from suspensions in ethanol, isopropanol and mixed ethanol—isopropanol solvents. The microstructure of as prepared and sintered deposits was studied by electron microscopy. The bath composition was optimized to enable formation of dense deposits. 相似文献
67.
68.
69.
70.
John Watrous 《Computational Complexity》2003,12(1-2):48-84
This paper studies the space-complexity of predicting the
long-term behavior of a class of stochastic processes based on evolutions
and measurements of quantum mechanical systems. These processes
generalize a wide range of both quantum and classical space-bounded
computations, including unbounded error computations given by machines
having algebraic number transition amplitudes or probabilities.
It is proved that any space s quantum stochastic process from this class
can be simulated probabilistically with unbounded error in space O(s),
and therefore deterministically in space O(s2). 相似文献