全文获取类型
收费全文 | 305934篇 |
免费 | 2459篇 |
国内免费 | 710篇 |
专业分类
化学 | 149862篇 |
晶体学 | 3551篇 |
力学 | 14852篇 |
综合类 | 4篇 |
数学 | 45170篇 |
物理学 | 95664篇 |
出版年
2018年 | 10541篇 |
2017年 | 11454篇 |
2016年 | 6661篇 |
2015年 | 2862篇 |
2014年 | 2787篇 |
2013年 | 8589篇 |
2012年 | 10284篇 |
2011年 | 20260篇 |
2010年 | 12339篇 |
2009年 | 12277篇 |
2008年 | 17631篇 |
2007年 | 21276篇 |
2006年 | 6841篇 |
2005年 | 13518篇 |
2004年 | 9333篇 |
2003年 | 8461篇 |
2002年 | 5810篇 |
2001年 | 5856篇 |
2000年 | 4532篇 |
1999年 | 3345篇 |
1998年 | 2582篇 |
1997年 | 2730篇 |
1996年 | 2856篇 |
1995年 | 2658篇 |
1994年 | 2538篇 |
1993年 | 2396篇 |
1992年 | 2883篇 |
1991年 | 2746篇 |
1990年 | 2705篇 |
1989年 | 2723篇 |
1988年 | 2681篇 |
1987年 | 2690篇 |
1986年 | 2482篇 |
1985年 | 3509篇 |
1984年 | 3521篇 |
1983年 | 2871篇 |
1982年 | 3139篇 |
1981年 | 3044篇 |
1980年 | 2978篇 |
1979年 | 3131篇 |
1978年 | 3396篇 |
1977年 | 3135篇 |
1976年 | 3091篇 |
1975年 | 2894篇 |
1974年 | 2836篇 |
1973年 | 2895篇 |
1972年 | 1817篇 |
1968年 | 2054篇 |
1967年 | 2190篇 |
1966年 | 1999篇 |
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
1.
Mathematical Programming - We seek tight bounds on the viable parallelism in asynchronous implementations of coordinate descent that achieves linear speedup. We focus on asynchronous coordinate... 相似文献
2.
Kobayashi M. Zhang Y. Ishikawa H. Sun J. Oddershede J. Juul Jensen D. Miura H. 《Experimental Mechanics》2021,61(5):817-828
Experimental Mechanics - The internal strain distribution developing during plastic deformation is important for understanding the mechanical properties of polycrystalline materials. Such... 相似文献
3.
Journal of Applied Spectroscopy - With the COVID-19 outbreak, many challenges are posed before the scientific world to curb this pandemic. The diagnostic testing, treatment, and vaccine development... 相似文献
4.
Analysis Mathematica - We introduce and study the k-Hankel Gabor transform. We investigate the localization operators for this transform. In particular, we study their trace class properties and we... 相似文献
5.
Experimental Mechanics - Ratcheting is an important mechanical behavior of metals and alloys, which is caused by the repeated accumulations of tensile and compressive strain in circle load.... 相似文献
6.
Butenko A. V. Galimov A. R. Meshkov I. N. Syresin E. M. Tolstikhina I. Yu. Tuzikov A. V. Philippov A. V. Khodzhibagiyan H. G. Shevel’ko V. P. 《JETP Letters》2021,113(12):752-756
JETP Letters - The results of the first run (December 2020) for the commissioning of the new superconducting synchrotron Booster at the Joint Institute for Nuclear Research are presented. Vacuum... 相似文献
7.
Alawainati F. A. Manaa H. Henari F. Z. Biyiklioglu Z. Arslan T. Jaafar A. 《Journal of Applied Spectroscopy》2021,88(5):951-957
Journal of Applied Spectroscopy - Detailed measurements of nonlinear optical properties and optical limiting for four phthalocyanine (Pc) derivatives (PcCo, PcCu, PcMn, and PcSi) are reported. The... 相似文献
8.
Nonlinear Dynamics - The paper studies the stability and control of radial deployment of an electric solar wind sail with the consideration of high-order modes of elastic tethers. The electric... 相似文献
9.
Jared P. Klein Zachary M. Gdowski Richard A. Register 《Journal of polymer science. Part A, Polymer chemistry》2022,60(2):266-275
Though polynorbornene synthesized by ring-opening metathesis polymerization has an intrinsically all-cis configuration of the cyclopentylene backbone rings, a fraction of these rings can be epimerized to the trans configuration during hydrogenation over suitable catalysts. By varying the method of hydrogenation, semicrystalline hydrogenated polynorbornenes (hPNs) with trans levels between 0 and 36% were obtained. With increasing trans content, the glass transition temperature, melting point, and enthalpy of melting decrease modestly. By contrast, the temperature at which the hPN crystal transitions into a rotationally disordered polymorph varies strongly with trans content, ranging from 126 °C (all-cis) to 71 °C at 27% trans; at trans contents of 34% and above, no rotationally-ordered phase is observed at any temperature. The room-temperature Young's modulus shows no dependence on trans content, while the yield stress drops by 20% at 1% trans content and slowly decreases further with additional epimerization. The temperature dependence of the Young's modulus differs for trans-containing versus all-cis polymers, while the temperature dependence of the yield stress is set by the polymorph type (rotationally ordered vs. disordered). 相似文献
10.