全文获取类型
收费全文 | 10883篇 |
免费 | 1043篇 |
国内免费 | 564篇 |
专业分类
化学 | 2419篇 |
晶体学 | 147篇 |
力学 | 1128篇 |
综合类 | 93篇 |
数学 | 6742篇 |
物理学 | 1961篇 |
出版年
2024年 | 19篇 |
2023年 | 99篇 |
2022年 | 137篇 |
2021年 | 179篇 |
2020年 | 323篇 |
2019年 | 294篇 |
2018年 | 294篇 |
2017年 | 308篇 |
2016年 | 346篇 |
2015年 | 302篇 |
2014年 | 468篇 |
2013年 | 994篇 |
2012年 | 447篇 |
2011年 | 592篇 |
2010年 | 590篇 |
2009年 | 647篇 |
2008年 | 709篇 |
2007年 | 681篇 |
2006年 | 599篇 |
2005年 | 546篇 |
2004年 | 467篇 |
2003年 | 431篇 |
2002年 | 428篇 |
2001年 | 329篇 |
2000年 | 251篇 |
1999年 | 254篇 |
1998年 | 200篇 |
1997年 | 192篇 |
1996年 | 167篇 |
1995年 | 129篇 |
1994年 | 125篇 |
1993年 | 99篇 |
1992年 | 91篇 |
1991年 | 77篇 |
1990年 | 59篇 |
1989年 | 44篇 |
1988年 | 47篇 |
1987年 | 31篇 |
1986年 | 47篇 |
1985年 | 51篇 |
1984年 | 56篇 |
1983年 | 41篇 |
1982年 | 56篇 |
1981年 | 44篇 |
1980年 | 41篇 |
1979年 | 48篇 |
1978年 | 32篇 |
1977年 | 17篇 |
1976年 | 21篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
2.
《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2021,38(5):1337-1371
In this paper we consider minimizers of the functional where is a bounded open set and where are the first k eigenvalues on Ω of an operator in divergence form with Dirichlet boundary condition and with Hölder continuous coefficients. We prove that the optimal sets have finite perimeter and that their free boundary is composed of a regular part, which is locally the graph of a -regular function, and a singular part, which is empty if , discrete if and of Hausdorff dimension at most if , for some . 相似文献
3.
4.
5.
Liang Zhao 《Journal of Differential Equations》2019,266(9):5615-5624
In this paper, let be n-dimensional noncompact metric measure space which satisfies Poincaré inequality with some Ricci curvature condition. We obtain a Liouville theorem for positive weak solutions to weighted p-Lichnerowicz equation where are real constants. 相似文献
6.
7.
This review provides a comprehensive evaluation of solidified floating organic drop microextraction (SFODME) procedures for metal ions preconcentration and their contributions to green chemistry. In this article we focused on the modifications that have been performed in the recent years to improve this environmentally friendly procedure. Among the most important of these modifications are the inclusion of ultrasonic energy, vortex and air agitation to enhance the dispersion process. The article also discussed new challenges in the procedure by using more ecofriendly solvents as extractants such as ionic liquids, deep eutectic. and supramolecular solvents. The coupling of SFODME with solid phase extraction increases selectivity and efficiency of the preconcentration procedure. 相似文献
8.
9.
Mariusz Marć Marek Tobiszewski Bożena Zabiegała Miguel de la Guardia Jacek Namieśnik 《Analytica chimica acta》2015
This review summarizes the different tools and concepts that are commonly applied in air quality monitoring. The monitoring of atmosphere is extremely important as the air quality is an important problem for large communities. Main requirements for analytical devices used for monitoring include a long period of autonomic operation and portability. These instruments, however, are often characterized by poor analytical performance. Monitoring networks are the most common tools used for monitoring, so large-scale monitoring programmes are summarized here. Biomonitoring, as a cheap and convenient alternative to traditional sample collection, is becoming more and more popular, although its main drawback is the lack of standard procedures. Telemonitoring is another approach to air monitoring, which offers some interesting opportunities, such as ease of coverage of large or remote areas, constituting a complementary approach to traditional strategies; however, it requires huge costs. 相似文献
10.
Bobby Wilson 《偏微分方程通讯》2015,40(8):1521-1542
This article explores the questions of long time orbital stability in high order Sobolev norms of plane wave solutions to the NLSE in the defocusing case. 相似文献