全文获取类型
收费全文 | 197868篇 |
免费 | 2116篇 |
国内免费 | 634篇 |
专业分类
电工技术 | 4061篇 |
综合类 | 123篇 |
化学工业 | 26704篇 |
金属工艺 | 7521篇 |
机械仪表 | 5462篇 |
建筑科学 | 4037篇 |
矿业工程 | 747篇 |
能源动力 | 4657篇 |
轻工业 | 14397篇 |
水利工程 | 1695篇 |
石油天然气 | 2842篇 |
武器工业 | 7篇 |
无线电 | 27296篇 |
一般工业技术 | 37405篇 |
冶金工业 | 45393篇 |
原子能技术 | 3561篇 |
自动化技术 | 14710篇 |
出版年
2021年 | 1245篇 |
2019年 | 1280篇 |
2018年 | 2124篇 |
2017年 | 2106篇 |
2016年 | 2173篇 |
2015年 | 1489篇 |
2014年 | 2618篇 |
2013年 | 7952篇 |
2012年 | 4463篇 |
2011年 | 6116篇 |
2010年 | 4937篇 |
2009年 | 5776篇 |
2008年 | 6152篇 |
2007年 | 6197篇 |
2006年 | 5640篇 |
2005年 | 5311篇 |
2004年 | 5254篇 |
2003年 | 5094篇 |
2002年 | 4900篇 |
2001年 | 5306篇 |
2000年 | 4916篇 |
1999年 | 5436篇 |
1998年 | 15621篇 |
1997年 | 10315篇 |
1996年 | 7930篇 |
1995年 | 5783篇 |
1994年 | 5013篇 |
1993年 | 5021篇 |
1992年 | 3386篇 |
1991年 | 3260篇 |
1990年 | 3216篇 |
1989年 | 3039篇 |
1988年 | 2785篇 |
1987年 | 2236篇 |
1986年 | 2302篇 |
1985年 | 2606篇 |
1984年 | 2312篇 |
1983年 | 2064篇 |
1982年 | 1901篇 |
1981年 | 2044篇 |
1980年 | 1791篇 |
1979年 | 1659篇 |
1978年 | 1656篇 |
1977年 | 2021篇 |
1976年 | 2704篇 |
1975年 | 1422篇 |
1974年 | 1369篇 |
1973年 | 1316篇 |
1972年 | 1124篇 |
1971年 | 956篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A. F. Lisovskii T. É. Gracheva E. S. Cherepenina I. V. Manzheleev 《Powder Metallurgy and Metal Ceramics》1988,27(6):445-449
Translated from Poroshkovaya Metallurgiya, No. 6(306), pp. 40–44, June, 1988. 相似文献
992.
993.
Vuong S.T. Lau A.C. Chan R.I. 《IEEE transactions on pattern analysis and machine intelligence》1988,14(3):384-393
The basic ideas underlying an Estelle-C compiler, which accepts an Estelle protocol specification and produces a protocol implementation in C, are presented. The implementation of the ISO (International Organization for Standardization) class-2 transparent protocol, using the semiautomatic approach, is discussed. A manual implementation of the protocol is performed and compared to the semiautomatic implementation. The semiautomatic approach to protocol implementation offers several advantages over the conventional manual one, including correctness and modularity in protocol implementation code, conformance to the specification, and reduction in implementation time. Finally, ongoing development of a new Estelle-C compiler is presented 相似文献
994.
995.
M. E. Fitzpatrick M. T. Hutchings J. E. King D. M. Knowles P. J. Withers 《Metallurgical and Materials Transactions A》1995,26(12):3191-3198
The effects of a thermal residual stress field on fatigue crack growth in a silicon carbide particle-reinforced aluminum alloy
have been measured. Stress fields were introduced into plates of material by means of a quench from a solution heat-treatment
temperature. Measurements using neutron diffraction have shown that this introduces an approximately parabolic stress field
into the plates, varying from compressive at the surfaces to tensile in the center. Long fatigue cracks were grown in specimens
cut from as-quenched plates and in specimens which were given a stress-relieving overaging heat treatment prior to testing.
Crack closure levels for these cracks were determined as a function of the position of the crack tip in the residual stress
field, and these are shown to differ between as-quenched and stress-relieved samples. By monitoring the compliance of the
specimens during fatigue cycling, the degree to which the residual stresses close the crack has been evaluated.
formerly Research Student, Department of Materials Science and Metallurgy, University of Cambridge
formerly Lecturer, Department of Materials Science and Metallurgy, University of Cambridge
This article is based on a presentation made in the symposium entitled “Creep and Fatigue in Metal Matrix Composites” at the
1994 TMS/ASM Spring meeting, held February 28–March 3, 1994, in San Francisco, California, under the auspices of the Joint
TMS-SMD/ASM-MSD Composite Materials Committee. 相似文献
996.
997.
At strain rates greater than about 10 the deformation of polymers is an adiabatic process which can lead to the generation of very high localized temperatures. These may be well in excess of the temperatures required for thermal decomposition of the polymer to occur. It is speculated that gaseous products arising from such decomposition may act as the source of microcavities and craze initiators. Experiments are described in which the thermal decomposition reaction parameters of polyetherketone, polyetheretherketone, and polysulphone are measured using differential scanning calorimetry and thermogravimetric analysis, and the decomposition products analysed by mass spectrometry. The results indicate that the proposed mechanism could act as a source of micropores with total pore volumes amounting to several per cent of the material volume. 相似文献
998.
V. B. Skribachilin T. E. Yampol'skaya G. V. Matyusha I. A. Timokhin S. A. Kalinovskii 《Chemistry and Technology of Fuels and Oils》1992,28(10):581-582
Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 10, pp. 21–22, October, 1992. 相似文献
999.
1000.