全文获取类型
收费全文 | 47867篇 |
免费 | 8374篇 |
国内免费 | 6156篇 |
专业分类
化学 | 36018篇 |
晶体学 | 681篇 |
力学 | 2562篇 |
综合类 | 367篇 |
数学 | 5029篇 |
物理学 | 17740篇 |
出版年
2024年 | 119篇 |
2023年 | 926篇 |
2022年 | 1252篇 |
2021年 | 1749篇 |
2020年 | 2084篇 |
2019年 | 2111篇 |
2018年 | 1731篇 |
2017年 | 1625篇 |
2016年 | 2405篇 |
2015年 | 2369篇 |
2014年 | 2969篇 |
2013年 | 3700篇 |
2012年 | 4477篇 |
2011年 | 4563篇 |
2010年 | 3077篇 |
2009年 | 2983篇 |
2008年 | 3378篇 |
2007年 | 2853篇 |
2006年 | 2708篇 |
2005年 | 2190篇 |
2004年 | 1726篇 |
2003年 | 1402篇 |
2002年 | 1549篇 |
2001年 | 1178篇 |
2000年 | 884篇 |
1999年 | 915篇 |
1998年 | 782篇 |
1997年 | 658篇 |
1996年 | 660篇 |
1995年 | 554篇 |
1994年 | 461篇 |
1993年 | 392篇 |
1992年 | 396篇 |
1991年 | 332篇 |
1990年 | 281篇 |
1989年 | 219篇 |
1988年 | 126篇 |
1987年 | 125篇 |
1986年 | 142篇 |
1985年 | 106篇 |
1984年 | 57篇 |
1983年 | 63篇 |
1982年 | 33篇 |
1981年 | 32篇 |
1980年 | 13篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1957年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
In this paper we study a particular class of primal-dual path-following methods which try to follow a trajectory of interior feasible solutions in primal-dual space toward an optimal solution to the primal and dual problem. The methods investigated are so-called first-order methods: each iteration consists of a long step along the tangent of the trajectory, followed by explicit recentering steps to get close to the trajectory again. It is shown that the complexity of these methods, which can be measured by the number of points close to the trajectory which have to be computed in order to achieve a desired gain in accuracy, is bounded by an integral along the trajectory. The integrand is a suitably weighted measure of the second derivative of the trajectory with respect to a distinguished path parameter, so the integral may be loosely called a curvature integral. 相似文献
995.
Morelos A Albuquerque IF Bondar NF Carrigan RA Chen D Cooper PS Lisheng D Denisov AS Dobrovolsky AV Dubbs T Endler AM Escobar CO Foucher M Golovtsov VL Gottschalk H Gouffon P Grachev VT Khanzadeev AV Kubantsev MA Kuropatkin NP Lach J Lang Pengfei Li Chengze Li Yunshan Luksys M Mahon JR McCliment E Newsom C Pommot Maia MC Samsonov VM Schegelsky VA Shi Huanzhang Smith VJ Tang Fukun Terentyev NK Timm S Tkatch II Uvarov LN Vorobyov AA Yan Jie Zhao Wenheng Shuchen Z Zhong Yuanyuan 《Physical review letters》1993,71(21):3417-3420
996.
Morelos A Albuquerque IF Bondar NF Carrigan RA Chen D Cooper PS Dai Lisheng Denisov AS Dobrovolsky AV Dubbs T Endler AM Escobar CO Foucher M Golovtsov VL Gottschalk H Gouffon P Grachev VT Khanzadeev AV Kubantsev MA Kuropatkin NP Lach J Lang Pengfei Li Chengze Li Yunshan Luksys M Mahon JR McCliment E Newsom C Pommot Maia MC Samsonov VM Schegelsky VA Shi Huanzhang Smith VJ Tang Fukun Terentyev NK Timm S Tkatch II Uvarov LN Vorobyov AA Yan Jie Zhao Wenheng Zheng Shuchen Zhong Yuanyuan 《Physical review letters》1993,71(14):2172-2175
997.
998.
999.
1000.
Diamond-like carbon (DLC) and tetrahedral amorphous carbon (ta-C) have attracted much attention recently for biomedical and antifouling applications due to their excellent biocompatibility and inherent nonstick properties. It has been demonstrated that the solid surface free energy is a dominant factor in cellular or fouling adhesion. However, few data for the surface free energy of DLC and ta-C coatings at temperatures in the range 37-95 degrees C are available. In this study DLC and ta-C coatings on stainless steel 304 sheets were prepared using an unbalanced magnetron sputtering system and a filtered cathodic vacuum arc system, respectively. The contact angles of water, diiodomethane and ethylene glycol on the coated surfaces at temperatures in the range 20-95 degrees C were measured using a Dataphysics OCA-20 contact angle analyzer. The surface free energy of the coatings and their components (e.g., dispersion, polar or acid/base portions) were calculated using various methods. The experimental results showed that the total surface free energy and dispersive surface free energy of the ta-C coatings, DLC coatings, stainless steel 304 and titanium decreased with increasing surface temperature, while the acid-base SFE component increased with increasing temperature. 相似文献