全文获取类型
收费全文 | 25930篇 |
免费 | 5814篇 |
国内免费 | 1367篇 |
专业分类
化学 | 2366篇 |
晶体学 | 227篇 |
力学 | 697篇 |
综合类 | 61篇 |
数学 | 267篇 |
物理学 | 14461篇 |
无线电 | 15032篇 |
出版年
2024年 | 55篇 |
2023年 | 153篇 |
2022年 | 300篇 |
2021年 | 494篇 |
2020年 | 501篇 |
2019年 | 351篇 |
2018年 | 404篇 |
2017年 | 698篇 |
2016年 | 783篇 |
2015年 | 907篇 |
2014年 | 1393篇 |
2013年 | 1266篇 |
2012年 | 1770篇 |
2011年 | 1863篇 |
2010年 | 1274篇 |
2009年 | 1363篇 |
2008年 | 1878篇 |
2007年 | 2052篇 |
2006年 | 1849篇 |
2005年 | 1624篇 |
2004年 | 1564篇 |
2003年 | 1285篇 |
2002年 | 1246篇 |
2001年 | 1106篇 |
2000年 | 1049篇 |
1999年 | 949篇 |
1998年 | 772篇 |
1997年 | 728篇 |
1996年 | 663篇 |
1995年 | 542篇 |
1994年 | 496篇 |
1993年 | 411篇 |
1992年 | 381篇 |
1991年 | 319篇 |
1990年 | 198篇 |
1989年 | 102篇 |
1988年 | 78篇 |
1987年 | 61篇 |
1986年 | 34篇 |
1985年 | 21篇 |
1984年 | 37篇 |
1983年 | 10篇 |
1982年 | 13篇 |
1981年 | 17篇 |
1980年 | 10篇 |
1979年 | 3篇 |
1976年 | 3篇 |
1975年 | 7篇 |
1974年 | 5篇 |
1973年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
15.
本文对高功率板条固体激光器研究的进展和应用前景作了综合评述。结合作者部分工作,对板条激光器的热效应、聚光器和光学谐振腔等关键问题和技术进行了物理分析。 相似文献
16.
17.
The dislocation structures of bulk textured and epitaxial thin film YBa2Cu3O7 superconductors are examined. Correlations between increases in flux pinning and dislocation densities are noted. A model
for flux pinning by individual dislocations is presented. This gives a treatment of strain induced effects and effects of
normal state region interactions. It is shown that the values of pinning predicted are in line with experimental observations. 相似文献
18.
Thermal diffusivity, heat capacity, and density of polyvinyl chloride/polycaprolactone (PVC/PCL) blends were measured by the laser flash method, DSC, and pycnometry, respectively. The thermal conductivity of the PVC/PCL blends was determined from the results. The miscibility of the blend and crystallinity of PCL were determined by DSC. The effect of blend structure on thermal conductivity is discussed. The phase compositions of the PVC/PCL blends are of three types depending on PCL content: i.e., up to 33%, from 33 to 70%, and above 70% PCL by weight. Thermal conductivity, thermal diffusivity, and heat capacity of the PVC/PCL blends are strongly affected by the phase composition of the blend, which changes in a complicated way with PCL content. © 1994 John Wiley & Sons, Inc. 相似文献
19.
Taking both the heterogeneous catalytic processes, including the surface formation of particles with excited internal degrees of freedom, and the processes of multicomponent diffusion and heat transfer in the MESOX apparatus fully into account makes it possible to obtain a recombination coefficient and an accommodation coefficient of the oxygen-atoms-on-quartz recombination energy which are in good agreement with the experimental data. The heterogeneous catalysis model constructed can be used effectively for predicting the heat fluxes to the surface of reentry vehicles on their entry into the Earth’s atmosphere. 相似文献
20.
CHEN Bao-Zhen HUANG Zu-Qia 《理论物理通讯》2004,42(9)
The theoretical signal-pressure curves are calculated from approximate analytical solutions of the coupledequations describing the third order parametric wave mixing in a gas-filled capillary of femto-second laser pulses. Thecomparison with the corresponding experimental curves suggests that the following three factors exert important influ-ences on the degree of fitting between the theoretical and experimental results: the walk-off, the phase modulation, andthe third order harmonic of idler pulse. 相似文献