全文获取类型
收费全文 | 37282篇 |
免费 | 2076篇 |
国内免费 | 963篇 |
专业分类
化学 | 25946篇 |
晶体学 | 250篇 |
力学 | 1051篇 |
综合类 | 50篇 |
数学 | 6222篇 |
物理学 | 6802篇 |
出版年
2023年 | 269篇 |
2022年 | 436篇 |
2021年 | 562篇 |
2020年 | 690篇 |
2019年 | 627篇 |
2018年 | 524篇 |
2017年 | 514篇 |
2016年 | 1024篇 |
2015年 | 978篇 |
2014年 | 1096篇 |
2013年 | 2041篇 |
2012年 | 2229篇 |
2011年 | 2546篇 |
2010年 | 1459篇 |
2009年 | 1323篇 |
2008年 | 2056篇 |
2007年 | 2036篇 |
2006年 | 2042篇 |
2005年 | 1848篇 |
2004年 | 1627篇 |
2003年 | 1303篇 |
2002年 | 1269篇 |
2001年 | 642篇 |
2000年 | 588篇 |
1999年 | 552篇 |
1998年 | 529篇 |
1997年 | 539篇 |
1996年 | 505篇 |
1995年 | 496篇 |
1994年 | 509篇 |
1993年 | 434篇 |
1992年 | 399篇 |
1991年 | 390篇 |
1990年 | 345篇 |
1989年 | 314篇 |
1988年 | 305篇 |
1987年 | 253篇 |
1986年 | 280篇 |
1985年 | 392篇 |
1984年 | 393篇 |
1983年 | 324篇 |
1982年 | 368篇 |
1981年 | 330篇 |
1980年 | 345篇 |
1979年 | 277篇 |
1978年 | 310篇 |
1977年 | 287篇 |
1976年 | 230篇 |
1975年 | 197篇 |
1974年 | 201篇 |
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
101.
Peter Karduck Norbert Ammann Hans Günter Esser Jörg Winter 《Fresenius' Journal of Analytical Chemistry》1991,341(5-6):315-319
Summary The first wall of the fusion device TEXTOR at the Forschungszentrum Jülich has been coated in situ with an amorphous hydrogen rich carbon/boron film (a-C/B:H) which reduces plasma impurities caused by the plasma surface interaction. The results of the coating process of the 35 m2 large inner wall surface have been controlled by a recently developed modification of the quantitative electron probe microanalysis, which has been applied to 12 samples from specified positions inside the tokamak. The quantification itself is based on a Monte Carlo simulation of electron trajectories providing very accurate results for X-ray intensities emitted by elements present in the electron bombarded sample. The Monte Carlo results are used in the present work to calibrate the measured X-ray intensities emitted by boron and carbon from the a-C/B:H layers deposited on pure silicon substrates. As a result the total deposited mass of the layer per area unit as well as the composition of the layers (except hydrogen) could be determined very accurately. The relative errors were less than 7%. The limit of detectability were found to be in the range of one monolayer for boron as well as for carbon. 相似文献
102.
103.
谐振子薛定谔方程的简单解法 总被引:2,自引:0,他引:2
物质的许多物理与化学性质都可以用线性谐振子模型解释,本文用简单的数学运算求解线性谐振子的薛定谔方程,避免了特殊函数等复杂的数学运算,得出了量子力学教材完全相同的结果。 相似文献
104.
Wang Dunhui Huang Songling Han Zhida Su Zhenghua Wang Yi Du Youwei 《Solid State Communications》2004,131(2):97-99
A series of Gd(1−x)Bx alloys have been prepared by arc melting method. After introducing small quantity of B atom in Gd, the Curie temperature of these alloys increase while the magnetic entropy changes are almost same as that of Gd. The refrigerant capacities of these alloys are also greater than that of Gd. These results suggest that Gd(1−x)Bx alloys may be utilized as refrigerant in household magnetic refrigeration. 相似文献
105.
106.
107.
Chii-Wann Lin Kuo-Ping Chen Ming-Chii Su Chih-Kung Lee Chih-Chung Yang 《Optical and Quantum Electronics》2005,37(13-15):1423-1437
We have reported a novel design of surface plasmon resonance (SPR) device, which uses alternating dielectric layers to enhance the SPR signal quality and modulate its resonant position. Admittance loci method of thin film design has been used in the design of such a device. The use of biomolecular thin film, such as DNAs or Porteins, in this design can result in resonant condition of wavelength changes as well. Bio-plasmonics is proposed for the research and development of novel devices, which use biomolecules as a part of the plasmon oscillation system to actively interact with nano/micro structure. 相似文献
108.
109.
Ohne ZusammenfassungDiese Arbeit wurde während eines Aufenthaltes von Schmidt in der Bundesrepublik Deutschland als Preisträger der Alexander von Humboldt-Stiftung geschrieben. 相似文献
110.
Butyltins were analyzed in waters from California river and lake marinas and were detected at the part per trillion (ppt) level in most locations. The tributyltin:dibutyltin (TBT/DBT) ratios in the fresh waters were similar to those in their saline counterparts indicating like rates of degradation in the two salinity regimes. 相似文献