全文获取类型
收费全文 | 168521篇 |
免费 | 5912篇 |
国内免费 | 4740篇 |
专业分类
化学 | 92773篇 |
晶体学 | 2430篇 |
力学 | 8600篇 |
综合类 | 323篇 |
数学 | 19243篇 |
物理学 | 55804篇 |
出版年
2022年 | 2243篇 |
2021年 | 2855篇 |
2020年 | 3126篇 |
2019年 | 3406篇 |
2018年 | 4198篇 |
2017年 | 4156篇 |
2016年 | 5299篇 |
2015年 | 3280篇 |
2014年 | 4935篇 |
2013年 | 7860篇 |
2012年 | 7671篇 |
2011年 | 8257篇 |
2010年 | 6513篇 |
2009年 | 6553篇 |
2008年 | 7138篇 |
2007年 | 6716篇 |
2006年 | 6290篇 |
2005年 | 5519篇 |
2004年 | 5033篇 |
2003年 | 4556篇 |
2002年 | 4695篇 |
2001年 | 4565篇 |
2000年 | 3452篇 |
1999年 | 2729篇 |
1998年 | 2554篇 |
1997年 | 2262篇 |
1996年 | 2100篇 |
1995年 | 1815篇 |
1994年 | 1880篇 |
1993年 | 1827篇 |
1992年 | 1846篇 |
1991年 | 1954篇 |
1990年 | 1894篇 |
1989年 | 1833篇 |
1988年 | 1658篇 |
1987年 | 1602篇 |
1986年 | 1568篇 |
1985年 | 1705篇 |
1984年 | 1813篇 |
1983年 | 1566篇 |
1982年 | 1588篇 |
1981年 | 1395篇 |
1980年 | 1316篇 |
1979年 | 1499篇 |
1978年 | 1642篇 |
1977年 | 1653篇 |
1976年 | 1675篇 |
1975年 | 1537篇 |
1974年 | 1575篇 |
1973年 | 1546篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Fundamental and dual variational principles of magnetostatics of superconductors are formulated. It is shown how test fields can be expressed in terms of vector and scalar potentials. General consequences of the variational magnetostatic formulation are discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 97–102, September, 1991. 相似文献
53.
54.
O. B. Lykova 《Ukrainian Mathematical Journal》1992,44(1):28-40
A survey is presented of some results relating to the development of the Bogolyubov-Mitropol'skii method of integral manifolds.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 44, No. 1, pp. 33–46, January, 1992. 相似文献
55.
56.
Haishan Bu Yanwan Pang Dandan Song Tongyin Yu T. M. Voll George Czornyj B. Wunderlich 《Journal of Polymer Science.Polymer Physics》1991,29(2):139-152
Various approaches to the preparation and verification of single-molecule single crystals are discussed for polyethylene and poly (oxyethylene). Analytic tools are electron microscopy, electron diffraction, and differential scanning calorimetry. The main difficulty in producing a single-molecule single crystal is to keep crystals from joining during growth. 相似文献
57.
The adsorption of nonionic surfactant Triton X-100 on quartz sand and methylated quartz sand from water and toluene was investigated by means of spectrophotometry, the radiotracer technique, and wetting angle measurements. 相似文献
58.
V. T. Bublik S. Yu. Matsnev K. D. Shcherbachev M. V. Mezhennyi M. G. Mil’vidskii V. Ya. Reznik 《Physics of the Solid State》2003,45(10):1918-1925
Diffuse x-ray scattering (DXS) is used to study the formation of microdefects (MDs) in heat-treated dislocation-free large-diameter silicon wafers with vacancies. The DXS method is shown to be efficient for investigating MDs in silicon single crystals. Specific defects, such as impurity clouds, are found to form in the silicon wafers during low-temperature annealing at 450°C. These defects are oxygen-rich regions in the solid solution with diffuse coherent interfaces. In the following stages of decomposition of the supersaturated solid solution, oxide precipitates form inside these regions and the impurity clouds disappear. As a result of the decomposition of the supersaturated solid solution of oxygen, interstitial MDs form in the silicon wafers during multistep heat treatment. These MDs lie in the {110} planes and have nonspherical displacement fields. The volume density and size of MDs forming in the silicon wafers at various stages of the decomposition are determined. 相似文献
59.
We investigate the dependence of the relaxation time of the current flowing in a nematic cell submitted to an external dc voltage on the physical properties of the substrate. We show that previously presented analyses of the same problem are not very useful for practical applications. We compare our theoretical predictions with experimental data, and show that the agreement is rather good. The influence of the adsorption-desorption phenomenon on the relaxation time is also discussed. 相似文献
60.
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