全文获取类型
收费全文 | 30134篇 |
免费 | 3823篇 |
国内免费 | 3395篇 |
专业分类
化学 | 21877篇 |
晶体学 | 372篇 |
力学 | 1545篇 |
综合类 | 272篇 |
数学 | 3863篇 |
物理学 | 9423篇 |
出版年
2024年 | 54篇 |
2023年 | 449篇 |
2022年 | 631篇 |
2021年 | 827篇 |
2020年 | 950篇 |
2019年 | 968篇 |
2018年 | 830篇 |
2017年 | 790篇 |
2016年 | 1178篇 |
2015年 | 1192篇 |
2014年 | 1430篇 |
2013年 | 1988篇 |
2012年 | 2401篇 |
2011年 | 2636篇 |
2010年 | 1873篇 |
2009年 | 1835篇 |
2008年 | 2030篇 |
2007年 | 1849篇 |
2006年 | 1677篇 |
2005年 | 1490篇 |
2004年 | 1158篇 |
2003年 | 947篇 |
2002年 | 920篇 |
2001年 | 766篇 |
2000年 | 675篇 |
1999年 | 638篇 |
1998年 | 563篇 |
1997年 | 489篇 |
1996年 | 531篇 |
1995年 | 425篇 |
1994年 | 395篇 |
1993年 | 359篇 |
1992年 | 335篇 |
1991年 | 289篇 |
1990年 | 243篇 |
1989年 | 203篇 |
1988年 | 174篇 |
1987年 | 132篇 |
1986年 | 149篇 |
1985年 | 156篇 |
1984年 | 103篇 |
1983年 | 67篇 |
1982年 | 71篇 |
1981年 | 54篇 |
1980年 | 52篇 |
1979年 | 58篇 |
1978年 | 40篇 |
1976年 | 37篇 |
1974年 | 40篇 |
1973年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
谈物理实验教学中学生科学素质的培养 总被引:3,自引:0,他引:3
物理教学要实现由“应试教育”向素质教育的转轨,必须改单纯的“学科教育”为“科学教育”,即不仅要让学生掌握必要的物理知识,还要为学生的整体素质发展奠定必需的科学能力和科学品质的基础.笔者通过多年的教学实践和研究深刻地认识到,在物理教学中,加强实验教学是培养学生科学素质的重要途径和关键,也是物理学科实施素质教育的一个十分重要的方面. 相似文献
42.
The present paper devotes to the long-time behavior of a class of reaction diffusion equations with delays under Dirichlet boundary conditions. The stability and global attractability for the zero solution are provided, and the existence, stability and attractability for the positive stationary solution are also obtained. 相似文献
43.
44.
The structural evolution in amorphous silicon and germanium thin films has been investigated by high-resolution transmission electron microscopy (HRTEM) in conjunction with autocorrelation function (ACF) analysis. The results established that the structure of as-deposited semiconductor films is of a high density of nanocrystallites embedded in the amorphous matrix. In addition, from ACF analysis, the structure of a-Ge is more ordered than that of a-Si. The density of embedded nanocrystallites in amorphous films was found to diminish with annealing temperature first, then to increase. The conclusions also corroborate well with the results of diminished medium-range order in annealed amorphous films determined previously by a variable coherence microscopy method. 相似文献
45.
Hui-Wen Lin 《Transactions of the American Mathematical Society》2002,354(5):1861-1868
In this article, we find some diagonal hypersurfaces that admit crepant resolutions. We also give a criterion for unique factorization domains.
46.
47.
48.
49.
The crystal structure, magnetic and magnetotransport properties of the variation of B′-site transition metal in Sr2FeMO6 (M=Mo, W) with double perovskites structure have been investigated systematically. Measurements of magnetization vs. temperature at H=5 T show that Sr2FeMoO6 is a ferromagnet and Sr2FeWO6 is an antiferromagnet with TN∼35 K. Additionally, the large magnetoresistance ratio (MR) of ∼22% (H=3 T) at room temperature (RT) was observed in the Sr2FeWO6 compound. However, the Sr2FeMoO6 compound did not show any significant MR even at high fields and RT (MR∼1%; H=3 T and 300 K). The implications of these findings are supported by band structure calculations to explain the interaction between the 4d(Mo) and 5d(W) orbitals of transition metal ions and oxygen ions. 相似文献
50.
Yang Mujie Zhao Jian Li Aibing Shen Zhiquan Zhang Mingjian Lin Senhao 《Journal of polymer science. Part A, Polymer chemistry》1989,27(11):3829-3835
This paper reports that 60Co γ-ray irradiation can convert cis-polyphenylacetylene (cis-PPA) films prepared with rare-earth coordination catalysts to highly photosensitive materials. The dependence of the photosensitivity on irradiation dose, preparation methods, and microstructure of the PPA films has been investigated by means of a potential discharge technique. The photosensitivity was enhanced with increasing irradiation dose. The critical dose to produce a light response was 5 × 103 Gy. The maximum surface potential discharge rate was 618 V/s, and the dark decay was approximately 2 V/s for cis-PPA films irradiated with 60Co γ-ray (dose: 2 × 105 Gy). The cis-transoidal-PPA and an electrophotographic photoreceptor device incorporating cis-PPA showed a higher irradiation effect. The structure and properties of 60Co γ-ray irradiated rare-earth PPA films are similar to the unirradiated films. 相似文献