全文获取类型
收费全文 | 37040篇 |
免费 | 1307篇 |
国内免费 | 260篇 |
专业分类
化学 | 26070篇 |
晶体学 | 280篇 |
力学 | 712篇 |
综合类 | 1篇 |
数学 | 6455篇 |
物理学 | 5089篇 |
出版年
2023年 | 162篇 |
2022年 | 210篇 |
2021年 | 441篇 |
2020年 | 626篇 |
2019年 | 616篇 |
2018年 | 431篇 |
2017年 | 393篇 |
2016年 | 974篇 |
2015年 | 859篇 |
2014年 | 1038篇 |
2013年 | 1771篇 |
2012年 | 2243篇 |
2011年 | 2539篇 |
2010年 | 1376篇 |
2009年 | 1227篇 |
2008年 | 2338篇 |
2007年 | 2160篇 |
2006年 | 2179篇 |
2005年 | 2020篇 |
2004年 | 1754篇 |
2003年 | 1412篇 |
2002年 | 1376篇 |
2001年 | 534篇 |
2000年 | 500篇 |
1999年 | 435篇 |
1998年 | 421篇 |
1997年 | 447篇 |
1996年 | 491篇 |
1995年 | 353篇 |
1994年 | 407篇 |
1993年 | 364篇 |
1992年 | 332篇 |
1991年 | 305篇 |
1990年 | 281篇 |
1989年 | 239篇 |
1988年 | 236篇 |
1987年 | 254篇 |
1986年 | 189篇 |
1985年 | 423篇 |
1984年 | 369篇 |
1983年 | 314篇 |
1982年 | 355篇 |
1981年 | 319篇 |
1980年 | 324篇 |
1979年 | 265篇 |
1978年 | 265篇 |
1977年 | 253篇 |
1976年 | 232篇 |
1975年 | 218篇 |
1974年 | 192篇 |
排序方式: 共有10000条查询结果,搜索用时 100 毫秒
11.
Mourad Kainane Mezadek Mohamed Kainane Mezadek Michael Reissig 《Mathematical Methods in the Applied Sciences》2020,43(6):3117-3147
In this paper, we study the global (in time) existence of small data solutions to the Cauchy problem for the semilinear wave equation with friction, viscoelastic damping, and a power nonlinearity. We are interested in the connection between regularity assumptions for the data and the admissible range of exponents p in the power nonlinearity. 相似文献
12.
13.
Amphiphilic thermoset elastomers from metal‐free,click crosslinking of PEG‐grafted silicone surfactants 下载免费PDF全文
Michael A. Brook Frances Lasowski Heather Sheardown 《Journal of polymer science. Part A, Polymer chemistry》2015,53(9):1082-1093
The hydrophobicity of silicone elastomers can compromise their utility in some biomaterials applications. Few effective processes exist to introduce hydrophilic groups onto a polysiloxane backbone and subsequently crosslink the material into elastomers. This problem can be overcome through the utilization of metal‐free click reactions between azidoalkylsilicones and alkynyl‐modified silicones and/or PEGs to both functionalize and crosslink silicone elastomers. Alkynyl‐functional PEG was clicked onto a fraction of the available azido groups of a functional polysiloxane, yielding azido reactive PDMS‐g‐PEG rake surfactants. The reactive polymers were then used to crosslink alkynyl‐terminated PDMS of different molecular weights. Using simple starting materials, this generic yet versatile method permits the preparation and characterization of a library of amphiphilic thermoset elastomers that vary in their composition, crosslink density, elasticity, hydrogel formation, and wettability. An appropriate balance of PEG length and crosslink density leads to a permanently highly wettable silicone elastomer that demonstrated very low levels of protein adsorption. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1082–1093 相似文献
14.
Michael Dickson 《Foundations of Physics》2015,45(10):1330-1340
15.
16.
17.
Simulating numerically the sound radiation of a rolling tire requires the solution of a very large and sparse gyroscopic eigenvalue problem. Taking advantage of the automated multi-level substructuring (AMLS) method it can be projected to a much smaller gyroscopic problem, the solution of which however is still quite costly since the eigenmodes are non-real and complex arithmetic is necessary. This paper discusses the application of AMLS to huge gyroscopic problems and the numerical solution of the AMLS reduction. A numerical example demonstrates the efficiency of AMLS. 相似文献
18.
19.
Partially supported by NSF Grants. 相似文献
20.