全文获取类型
收费全文 | 87107篇 |
免费 | 2464篇 |
国内免费 | 3532篇 |
专业分类
化学 | 47813篇 |
晶体学 | 1690篇 |
力学 | 3917篇 |
综合类 | 339篇 |
数学 | 9313篇 |
物理学 | 30031篇 |
出版年
2022年 | 992篇 |
2021年 | 1199篇 |
2020年 | 1328篇 |
2019年 | 1412篇 |
2018年 | 1976篇 |
2017年 | 2173篇 |
2016年 | 2501篇 |
2015年 | 1474篇 |
2014年 | 2342篇 |
2013年 | 4084篇 |
2012年 | 3631篇 |
2011年 | 4129篇 |
2010年 | 3460篇 |
2009年 | 3518篇 |
2008年 | 3975篇 |
2007年 | 3707篇 |
2006年 | 3604篇 |
2005年 | 3079篇 |
2004年 | 2751篇 |
2003年 | 2504篇 |
2002年 | 2553篇 |
2001年 | 2640篇 |
2000年 | 2100篇 |
1999年 | 1513篇 |
1998年 | 1257篇 |
1997年 | 1140篇 |
1996年 | 1017篇 |
1995年 | 902篇 |
1994年 | 912篇 |
1993年 | 891篇 |
1992年 | 938篇 |
1991年 | 991篇 |
1990年 | 929篇 |
1989年 | 951篇 |
1988年 | 861篇 |
1987年 | 795篇 |
1986年 | 767篇 |
1985年 | 887篇 |
1984年 | 987篇 |
1983年 | 839篇 |
1982年 | 851篇 |
1981年 | 765篇 |
1980年 | 714篇 |
1979年 | 780篇 |
1978年 | 897篇 |
1977年 | 914篇 |
1976年 | 809篇 |
1975年 | 777篇 |
1974年 | 792篇 |
1973年 | 760篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
V. T. Plaksiy O. N. Suchoruchko B. P. Yefimov A. P. Kasyanenko 《International Journal of Infrared and Millimeter Waves》2002,23(4):645-650
Bismuth, antimony and its alloys are the typical representatives of a class of semimetals, which electric conductance is lower in 102-103 times, than of usual well conducting an electrical current metals. The alloys bismuth with antimony have semi-conductor properties in wide area of compositions at temperatures below 77 °K. The semimetals are rather perspective materials from the point of view of their probable application in various devices [1,2,3].In present time the semimetal alloys BiSb have wide application in thermoelectric generators and refrigerators. In work [3] the opportunity of use of semimetals BiSb with percentage content of Bi and Sb from 8 % up to 25 % was shown as high-sensitivity and of small inertion indicators of the mm range radiation where thermoelectric effect is used. The principle of action of such indicators is based on occurrence of temperature gradient in a semimetal crystal BiSb that has two contacts of the various area with flowing electrical current. Basic element of such device is the dot contact metal - semimetal. One of the main characteristics is volt-watt sensitivity of metal-semimetal BiSb contact which calculating is shown in present work. 相似文献
52.
53.
An approach is proposed to solving multipoint boundary-value problems for linear differential equation of w-th order, based on reduction to two-point boundary-value problems. The two-point problems are solved by the stable discrete orthogonalization method. Some numerical examples are considered.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 58, pp. 36–45, 1986. 相似文献
54.
We obtain estimates for errors of interpolation on a nonuniform grid for a parabolic nonperiodic spline of defect 1. 相似文献
55.
56.
57.
Huw O. Pritchard 《国际化学动力学杂志》1994,26(1):61-71
The third-law method is used to assess the authenticity of available equilibrium constants for the thermal dissociation of N2O5 ? NO2 + NO3. © 1994 John Wiley & Sons, Inc. 相似文献
58.
O. S. Kushnir A. A. Bevz O. G. Vlokh L. F. Lutsiv-Shumskii 《Optics and Spectroscopy》2002,93(6):930-933
On the basis of a complex null-polarimetric method, the natural birefringence and the rotation of the optical indicatrix in crystals of deuterated triglycinesulfate are measured in the temperature range of 300–340 K. The temperature-dependent behavior of the optical parameters is shown to be close to that observed previously in triglycinesulfate crystals. Changes in them upon the ferroelectric phase transition can be accounted for by the spontaneous quadratic electro-optic effect, with the values of the electro-optic coefficients being larger by a factor of 1.4 than in triglycinesulfate crystals. 相似文献
59.
60.
Synthetic routes to oxidation of cobalt atoms in cobalt trimethylacetate complexes containing coordinated pyrazole molecules have been considered. 相似文献