全文获取类型
收费全文 | 18588篇 |
免费 | 501篇 |
国内免费 | 119篇 |
专业分类
化学 | 12336篇 |
晶体学 | 102篇 |
力学 | 358篇 |
数学 | 2965篇 |
物理学 | 2294篇 |
无线电 | 1153篇 |
出版年
2022年 | 99篇 |
2021年 | 163篇 |
2020年 | 187篇 |
2019年 | 190篇 |
2018年 | 152篇 |
2017年 | 152篇 |
2016年 | 314篇 |
2015年 | 336篇 |
2014年 | 358篇 |
2013年 | 774篇 |
2012年 | 788篇 |
2011年 | 1015篇 |
2010年 | 524篇 |
2009年 | 463篇 |
2008年 | 935篇 |
2007年 | 961篇 |
2006年 | 991篇 |
2005年 | 1047篇 |
2004年 | 919篇 |
2003年 | 763篇 |
2002年 | 681篇 |
2001年 | 238篇 |
2000年 | 233篇 |
1999年 | 187篇 |
1998年 | 192篇 |
1997年 | 228篇 |
1996年 | 303篇 |
1995年 | 200篇 |
1994年 | 202篇 |
1993年 | 190篇 |
1992年 | 201篇 |
1991年 | 166篇 |
1990年 | 158篇 |
1989年 | 153篇 |
1988年 | 161篇 |
1987年 | 188篇 |
1986年 | 148篇 |
1985年 | 299篇 |
1984年 | 277篇 |
1983年 | 208篇 |
1982年 | 287篇 |
1981年 | 227篇 |
1980年 | 289篇 |
1979年 | 254篇 |
1978年 | 257篇 |
1977年 | 277篇 |
1976年 | 225篇 |
1975年 | 196篇 |
1974年 | 182篇 |
1973年 | 184篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Crosslinked poly(ethylene oxide) containing siloxanes fabricated through thiol‐ene photochemistry 下载免费PDF全文
Victor A. Kusuma Elliot A. Roth William P. Clafshenkel Steven S. Klara Xu Zhou Surendar R. Venna Erik Albenze David R. Luebke Meagan S. Mauter Richard R. Koepsel Alan J. Russell David Hopkinson Hunaid B. Nulwala 《Journal of polymer science. Part A, Polymer chemistry》2015,53(13):1548-1557
Homogenous amphiphilic crosslinked polymer films comprising of poly(ethylene oxide) and polysiloxane were synthesized utilizing thiol‐ene “ click ” photochemistry. A systematic variation in polymer composition was Carried out to obtain high quality films with varied amount of siloxane and poly(ethylene oxide). These films showed improved gas separation performance with high gas permeabilities with good CO2/N2 selectivity. Furthermore, the resulting films were also tested for its biocompatibility, as a carrier media which allow human adult mesenchymal stem cells to retain their capacity for osteoblastic differentiation after transplantation. The obtained crosslinked films were characterized using differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis, FTIR, Raman‐IR , and small angle X‐ray scattering. The synthesis ease and commercial availability of the starting materials suggests that these new crosslinked polymer networks could find applications in wide range of applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1548–1557 相似文献
2.
3.
可重定位的基于事务的系统级验证 总被引:2,自引:0,他引:2
功能验证已经成为开发SoC的主要问题。随着一些复杂SoC的规模超过两千万门,以及对开发和集成嵌入式软件的需求持续增加,软件模拟器已经力所不及。在设计过程需要几百万个时钟周期来充分测试和验证软件功能的情况下,软件仿真器的性能下降到1-5Hz。按照这种速率,软件调试需要几年的时 相似文献
4.
W. Richard Strark 《Mathematical Logic Quarterly》1989,35(4):311-320
5.
6.
In this note we consider asymptotic results for self-intersections of closed geodesics on surfaces for which the angle of the intersection occurs in a given arc. We do this by extending Bonahon's definition of intersection forms for surfaces.
7.
Richard Moeckel 《Transactions of the American Mathematical Society》2005,357(8):3105-3117
The five relative equilibria of the three-body problem give rise to solutions where the bodies rotate rigidly around their center of mass. For these solutions, the moment of inertia of the bodies with respect to the center of mass is clearly constant. Saari conjectured that these rigid motions are the only solutions with constant moment of inertia. This result will be proved here for the planar problem with three nonzero masses with the help of some computational algebra and geometry.
8.
Richard Kissling 《Fresenius' Journal of Analytical Chemistry》1885,24(1):64-65
Ohne Zusammenfassung 相似文献
9.
Guido Wauters Jacques Dewaele Carlo Vandecasteele Richard Dams 《Mikrochimica acta》1989,98(4-6):157-162
Proton activation analysis was used for the determination of cadmium and lead in three sediment reference materials. The method is based on the111,112Cd(p, xn)111 In and the206,207,208Pb(p, xn)206Bi reactions.111In and206Bi were chemically separated by anion exchange. The results obtained were taken into account for the certification of the materials and are in the excellent agreement with the certified values. 相似文献
10.