全文获取类型
收费全文 | 248842篇 |
免费 | 1797篇 |
国内免费 | 265篇 |
专业分类
电工技术 | 4039篇 |
综合类 | 91篇 |
化学工业 | 40324篇 |
金属工艺 | 15143篇 |
机械仪表 | 10061篇 |
建筑科学 | 4175篇 |
矿业工程 | 3759篇 |
能源动力 | 3872篇 |
轻工业 | 9696篇 |
水利工程 | 4087篇 |
石油天然气 | 13006篇 |
武器工业 | 28篇 |
无线电 | 20186篇 |
一般工业技术 | 62748篇 |
冶金工业 | 32132篇 |
原子能技术 | 11134篇 |
自动化技术 | 16423篇 |
出版年
2021年 | 2753篇 |
2019年 | 2730篇 |
2018年 | 5429篇 |
2017年 | 5710篇 |
2016年 | 6044篇 |
2015年 | 3052篇 |
2014年 | 5323篇 |
2013年 | 10082篇 |
2012年 | 7303篇 |
2011年 | 8925篇 |
2010年 | 7293篇 |
2009年 | 8103篇 |
2008年 | 8171篇 |
2007年 | 7855篇 |
2006年 | 6356篇 |
2005年 | 5564篇 |
2004年 | 5478篇 |
2003年 | 5300篇 |
2002年 | 5133篇 |
2001年 | 4948篇 |
2000年 | 4937篇 |
1999年 | 4252篇 |
1998年 | 7173篇 |
1997年 | 5832篇 |
1996年 | 4420篇 |
1995年 | 3653篇 |
1994年 | 3422篇 |
1993年 | 3623篇 |
1992年 | 3214篇 |
1991年 | 3359篇 |
1990年 | 3481篇 |
1989年 | 3369篇 |
1988年 | 3267篇 |
1987年 | 3260篇 |
1986年 | 3156篇 |
1985年 | 3314篇 |
1984年 | 3252篇 |
1983年 | 3146篇 |
1982年 | 2993篇 |
1981年 | 3045篇 |
1980年 | 3071篇 |
1979年 | 3257篇 |
1978年 | 3490篇 |
1977年 | 3460篇 |
1976年 | 3911篇 |
1975年 | 3209篇 |
1974年 | 3293篇 |
1973年 | 3341篇 |
1972年 | 2987篇 |
1971年 | 2754篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Blair J.D. Correale A. Jr. Cranford H.C. Dombrowski D.A. Erdelyi C.K. Hoffman C.R. Lamphere J.L. Lang K.W. Lee J.K. Mullen J.M. Norman V.R. Oakland S.F. 《Solid-State Circuits, IEEE Journal of》1989,24(6):1647-1655
The authors describe a 9.02×9.02-mm chip built in 1-μm CMOS with two levels of metal and an additional mask level for fabricating capacitors. It contains both analog and digital circuits and has provisions for self-test. The function includes the transmitter, receiver, protocol handler, an microprocessor, as well as interfaces for RAM/ROM storage, IBM PC bus, IBM PS/2 bus, IBM 3174 bus, and Motorola 68000 bus. The physical design terrains are formed by 24K circuits of standard cell gates, a 10K-circuit equivalent hand-honed custom microprocessor, and an analog macro. The chip operates from a single 5-V supply, and the power consumption is 0.8 W nominal at 16 Mb/s. The chip can also be operated at 4 Mb/s 相似文献
992.
V A Meshcheriakova M A Samsonov I A Frolova O A Plotnikova G R Pokrovskaia 《Voprosy pitaniia》1985,(3):9-13
A study was made of the effect of wheat bran contained by the antisclerotic diet on lipid metabolism in patients with chronic coronary heart disease. Eighty-two patients (males) aged 36-59 years with a history of myocardial infarction of 1- to 15 year-standing were entered into the study. It was ascertained that inclusion into the antisclerotic diet of wheat bran in an amount of 70-80 g does not exert any hypolipidemic action. No elevation of the serum alpha-cholesterol content was noticed either. The augmentation of the cholic acid concentration together with a reduction in the cholesterol content in the hepatic bile attests to its reduced lithogenicity. 相似文献
993.
V.R.S. Hutton 《Geothermics》1985,14(5-6)
The initial problems associated with the fieldwork and integration of the results of four independent European university research groups involved in magnetotelluric studies in the Travale Test Site are discussed. This is followed by an account of the development of collaborative field studies, rewarding data and computer programme interchange and finally compatibility in the resulting electrical conductivity models and their interpretation. A suggested strategy for future EEC collaborative geothermal studies concludes this overview. 相似文献
994.
V. G. Rifert P. A. Barabash A. I. Sardak A. N. Tobilevich 《Journal of Engineering Physics and Thermophysics》1985,49(2):886-890
Measurements are made of local heat-transfer coefficients in the condensation of vapor with allowance for the effect of surface forces on hydrodynamics.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 49, No. 2, pp. 189–194, August, 1985. 相似文献
995.
A. O. Skomorokhov V. N. Kutinsky M. T. Slepov 《Pattern Recognition and Image Analysis》2006,16(1):85-88
The paper describes a few modifications of the classification tree construction algorithm that have proved to be useful for
solving tasks of noise spectra processing with reference to NPP diagnostics.
The article was translated by the authors. 相似文献
996.
Optimization of starting regimes of industrial plasmatrons is considered. Dependences of the surface temperature in the bath with liquid metal on the inputted specific power are obtained. These dependences may be used for determining the optimal melting conditions and calculating the kinetic regimes for refining metals. 相似文献
997.
I. Ya. Braslavskii A. V. Kostylev D. V. Mezeusheva 《Russian Electrical Engineering》2007,78(11):603-606
The use of prognostic control methods in the digital systems controlling asynchronous electric drives are considered. The methodology for synthesizing predictors on the basis of neural networks is explained. An example of the synthesis of a numeral predictor for a closed control loop is considered. 相似文献
998.
999.
1000.
V. N. Serebryany A. Ya. Kochubei S. F. Kurtasov K. E. Mel’nikov 《Russian Metallurgy (Metally)》2007,(1):73-78
Quantitative texture analysis is used to study texture formation in an MA2-1 magnesium alloy subjected to axisymmetric upsetting at temperatures of 250–450°C and strain rates of 10?4–100 ?1. The deformed structure is examined by optical microscopy, and the results obtained are used to plot the structural-state diagram of the alloy after 50% upsetting. The experimental textures are compared with the textures calculated in terms of a thermoactivation model. 相似文献