全文获取类型
收费全文 | 50940篇 |
免费 | 10945篇 |
国内免费 | 4627篇 |
专业分类
化学 | 51922篇 |
晶体学 | 597篇 |
力学 | 1370篇 |
综合类 | 272篇 |
数学 | 3767篇 |
物理学 | 8584篇 |
出版年
2024年 | 53篇 |
2023年 | 329篇 |
2022年 | 631篇 |
2021年 | 844篇 |
2020年 | 1876篇 |
2019年 | 3199篇 |
2018年 | 1558篇 |
2017年 | 1308篇 |
2016年 | 4114篇 |
2015年 | 4305篇 |
2014年 | 4400篇 |
2013年 | 5276篇 |
2012年 | 4332篇 |
2011年 | 3514篇 |
2010年 | 3959篇 |
2009年 | 3933篇 |
2008年 | 3488篇 |
2007年 | 2782篇 |
2006年 | 2405篇 |
2005年 | 2396篇 |
2004年 | 2025篇 |
2003年 | 1855篇 |
2002年 | 2498篇 |
2001年 | 1773篇 |
2000年 | 1606篇 |
1999年 | 633篇 |
1998年 | 270篇 |
1997年 | 204篇 |
1996年 | 185篇 |
1995年 | 127篇 |
1994年 | 117篇 |
1993年 | 101篇 |
1992年 | 82篇 |
1991年 | 77篇 |
1990年 | 66篇 |
1989年 | 43篇 |
1988年 | 28篇 |
1987年 | 24篇 |
1986年 | 28篇 |
1985年 | 14篇 |
1984年 | 6篇 |
1983年 | 11篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1979年 | 5篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1971年 | 4篇 |
1968年 | 2篇 |
1959年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
121.
122.
Tracy Huziak‐Clark Stephen J. Van Hook Julie Nurnberger‐Haag Lena Ballone‐Duran 《School science and mathematics》2007,107(8):311-324
This article focuses on the impact a collaborative project between university graduate fellows and K‐12 classroom teachers had on improved pedagogy in the classroom and in the future at the university. Nine teams participated in a yearlong professional development project to improve pedagogy and communication skills of the participants. This study shows that the participants, the fellows and the K‐12 teacher partners, made changes in planning, implementation, and even motivation for using inquiry‐based methods in their classroom. External observations of the teams further support the individuals' claims of improved pedagogy using inquiry and impact on student conceptual understanding. The Horizon Classroom Observation instrument was used for these observations. The teams showed an overall increase in scores, as well as overall effective and exemplarily implementation of their planning. The program design, the implementation, and the results of this three‐year study will be elaborated in this article. 相似文献
123.
124.
125.
126.
This work reports a new synthetic approach for single‐phase TiO2 nanomaterials by solvothermal treatment of titanium tetrachloride in acetone at 80–110 °C. Small, uniform, and yet size‐tunable (5–10 nm) anatase titania nanocrystallites were obtained using a low concentration of TiCl4 in acetone (i.e., at molar ratios of TiCl4/acetone ≤ 1:15) in the temperature range of 80–110 °C, while rutile nanofibers were synthesized using a high concentration of TiCl4 (e.g., TiCl4/acetone = 1:10) at 110 °C. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
127.
128.
129.
The fission barrier for ^240pu is investigated beyond the second saddle point in the potentiM energy surface by the constrained relativistic mean field method with the newly proposed parameter set PK1. The microscopic correction for the centre-of-mass motion is essentiM to provide the correct potential energy surface. The shell effects that stabilize the nuclei against the fission is also investigated by the Strutinsky method. The shapes for the ground state, fission isomer and saddle-points, etc, are studied in detail. 相似文献
130.
In this note we study constant mean curvature surfaces in asymptotically flat 3-manifolds. We prove that, outside a given compact subset in an asymptotically flat 3-manifold with positive mass, stable spheres of given constant mean curvature are unique. Therefore we are able to conclude that the foliation of stable spheres of constant mean curvature in an asymptotically flat 3-manifold with positive mass outside a given compact subset is unique.