全文获取类型
收费全文 | 1580篇 |
免费 | 66篇 |
国内免费 | 4篇 |
专业分类
化学 | 1211篇 |
晶体学 | 11篇 |
力学 | 26篇 |
数学 | 208篇 |
物理学 | 194篇 |
出版年
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 12篇 |
2019年 | 18篇 |
2018年 | 10篇 |
2016年 | 28篇 |
2015年 | 48篇 |
2014年 | 39篇 |
2013年 | 86篇 |
2012年 | 87篇 |
2011年 | 79篇 |
2010年 | 46篇 |
2009年 | 40篇 |
2008年 | 72篇 |
2007年 | 62篇 |
2006年 | 50篇 |
2005年 | 64篇 |
2004年 | 61篇 |
2003年 | 32篇 |
2002年 | 43篇 |
2001年 | 22篇 |
2000年 | 33篇 |
1999年 | 24篇 |
1998年 | 25篇 |
1997年 | 37篇 |
1996年 | 32篇 |
1995年 | 33篇 |
1994年 | 32篇 |
1993年 | 43篇 |
1992年 | 22篇 |
1991年 | 26篇 |
1990年 | 18篇 |
1989年 | 19篇 |
1988年 | 31篇 |
1987年 | 17篇 |
1986年 | 19篇 |
1985年 | 24篇 |
1984年 | 18篇 |
1983年 | 25篇 |
1982年 | 17篇 |
1981年 | 15篇 |
1980年 | 16篇 |
1979年 | 23篇 |
1978年 | 40篇 |
1977年 | 21篇 |
1976年 | 15篇 |
1975年 | 19篇 |
1974年 | 13篇 |
1973年 | 18篇 |
1972年 | 10篇 |
排序方式: 共有1650条查询结果,搜索用时 140 毫秒
1.
2.
In this paper a new multidimensional extension of the recently developed one-dimensional enclosure method called kite is given for interval global optimization. A more sophisticated version of the pruning technique based on the kite method is introduced. By the new componentwise approach all the one-dimensional theoretical results and procedures can be used in the higher-dimensional case. The possibilities in the implementation of the new algorithm together with numerical results on 40 standard test problems are presented. 相似文献
3.
4.
5.
Thermal properties of benzoic acids carrying one or two semiperfluorinated alkoxy tails on the aromatic core have been investigated in binary mixtures with the non-liquid crystalline bidirectional trans-1,2-bis(4-pyridyl)ethylene. The hydrogen bonded complexes built from the complementary molecular species show a significantly enhanced mesophase stability compared with the fluorinated acids in their pure states. The mesophase morphologies of the complexes are governed mainly by the number of the partially fluorinated chains grafted to the acid component. Mixed systems comprising the one-chain acids exhibit a smectic C phase followed by a smectic A phase at more elevated temperatures. Incorporation of a second semiperfluorinated chain into the acid leads to the formation of columnar mesophases. These columnar phases of the H-bonded complexes should represent ribbon phases resulting from the collapse of the smectic layers. 相似文献
6.
H.-J. Kluge B. A. Bushaw G. Passler K. Wendt N. Trautmann 《Fresenius' Journal of Analytical Chemistry》1994,350(4-5):323-329
Resonance ionization spectroscopy (RIS) and its combination with mass spectrometry (RIMS) have grown to become powerful techniques, which offer high sensitivity as well as elemental and isotopic selectivity. The principles of RIS and RIMS are introduced; they primarily concern the analysis of the optical spectra for the choice of efficient excitation schemes and the suitable design of the experimental apparatus. Recent applications span from studies of short-lived isotopes at on-line mass separators to a wide variety of trace analysis applications for radioactive isotopes, which can range from measurements of solar neutrino flux to environmental assessment.On leave from Pacific Northwest Laboratory, Richland, USA 相似文献
7.
8.
9.
10.
Tracks made in minerals by the electronic stopping of uranium fission fragments provide a modern geological dating tool, and are believed also to yield specific information on the low-temperature thermal history of rocks. Experimental work showing that the damaged crystal lattice along a fission track recovers primarily as a function of temperature ignored the fact that the basic theory of atomic diffusion requires an exponential decrease in the intrinsic diffusion coefficient with increasing pressure. Here, fission track recovery was experimentally investigated in basic apatite under the simultaneous influences of temperature, pressure and stress. We show that track fading is a complex recovery mechanism responding to several environmental physical parameters simultaneously. In particular a strong decrease in the track recovery rate was observed as a function of increasing pressure. And a nearly temperature-independent recovery was observed in samples under stress. 相似文献