全文获取类型
收费全文 | 87419篇 |
免费 | 663篇 |
国内免费 | 153篇 |
专业分类
化学 | 42693篇 |
晶体学 | 1267篇 |
力学 | 3319篇 |
综合类 | 1篇 |
数学 | 8226篇 |
物理学 | 25243篇 |
无线电 | 7486篇 |
出版年
2022年 | 683篇 |
2021年 | 959篇 |
2020年 | 1097篇 |
2019年 | 1229篇 |
2018年 | 1736篇 |
2017年 | 1847篇 |
2016年 | 2348篇 |
2015年 | 1126篇 |
2014年 | 1912篇 |
2013年 | 3596篇 |
2012年 | 3235篇 |
2011年 | 3621篇 |
2010年 | 2967篇 |
2009年 | 3042篇 |
2008年 | 3474篇 |
2007年 | 3437篇 |
2006年 | 3265篇 |
2005年 | 2980篇 |
2004年 | 2695篇 |
2003年 | 2530篇 |
2002年 | 2519篇 |
2001年 | 2522篇 |
2000年 | 1922篇 |
1999年 | 1516篇 |
1998年 | 1383篇 |
1997年 | 1266篇 |
1996年 | 1105篇 |
1995年 | 1004篇 |
1994年 | 986篇 |
1993年 | 961篇 |
1992年 | 1001篇 |
1991年 | 1071篇 |
1990年 | 1027篇 |
1989年 | 1023篇 |
1988年 | 922篇 |
1987年 | 833篇 |
1986年 | 808篇 |
1985年 | 954篇 |
1984年 | 1025篇 |
1983年 | 870篇 |
1982年 | 887篇 |
1981年 | 788篇 |
1980年 | 734篇 |
1979年 | 803篇 |
1978年 | 916篇 |
1977年 | 949篇 |
1976年 | 837篇 |
1975年 | 799篇 |
1974年 | 817篇 |
1973年 | 793篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
32.
V. A. Zayats A. N. Nikolaevskii T. A. Filippenko O. P. Kniga G. A. Tikhonova 《Russian Journal of Applied Chemistry》2006,79(10):1651-1654
Specific features of the initiated oxidation of polyethylene and its low-molecular-weight analogue tridecane, associated with the occurrence of the process in the short-chain mode, were studied. 相似文献
33.
34.
A method for measuring the characteristics of tunneling and impact ionization in thin-film electroluminescent emitters is suggested. This method makes it possible to find time dependences of the space-charge layer thickness near the anode and the length of the impact ionization region, to determine more exactly the time dependence of the field in the potential barrier at the cathode interface, the maximum depth of the surface states from which electron tunneling occurs, the minimum thickness of the barrier, and the electron tunneling probability, as well as the impact ionization rate for the deep centers related to structural defects of the phosphor layer. 相似文献
35.
O. S. Trushin 《Russian Microelectronics》2008,37(6):363-372
Atomic mechanisms of elastic-stress relaxation in heteroepitaxial structures are investigated by computer simulation. A 2D model of a heteroepitaxial structure with an empirical interatomic potential is considered. Advanced methods of saddle-point search in a multidimensional space are used to identify main mechanisms of structural change involving the formation of a structural imperfection, and to estimate energy characteristics of the processes. 相似文献
36.
A. A. Nechitaĭlov T. K. Zvonareva A. D. Remenyuk V. A. Tolmachev D. N. Goryachev O. S. El’tsina L. V. Belyakov O. M. Sreseli 《Semiconductors》2008,42(10):1249-1254
Catalytic properties of composite amorphous carbon-platinum layers produced by magnetron cosputtering have been studied. The layers were characterized by electron microscopy, IR spectroscopy, ellipsometry, gravimetry, and spectrophotometric chemical analysis. The catalytic activity of the layers was studied in an air-hydrogen fuel cell by measuring its load and power characteristics. 相似文献
37.
D. D. Avrov S. I. Dorozhkin Yu. M. Tairov A. Yu. Fadeev A. O. Lebedev 《Semiconductors》2008,42(13):1469-1474
The problem of the appearance of carbon inclusions in single-crystal silicon carbide ingots grown by the modified Lely method (the so-called graphitization of the ingot) is analyzed. It is shown that the process of graphitization of the ingot is not related to a deficit of silicon in the growth cell; in contrast, it is excess of silicon at the growth surface that inhibits the ingot growth rate and gives rise to intense corrosion of the graphite fittings. 相似文献
38.
Piryatinskiĭ Yu. P. Yaroshchuk O. V. Dolgov L. A. Bidna T. V. Enke D. 《Optics and Spectroscopy》2004,97(4):537-542
Optics and Spectroscopy - The fluorescence of the nematic liquid crystal n-butyl-n′-methoxyazoxybenzene (BMAOB) in the form of a layer and in porous glasses with pores of different diameter... 相似文献
39.
O. I. Reinov 《Journal of Mathematical Sciences》2003,115(2):2243-2250
We investigate Banach spaces possessing (or not possessing) the approximation properties AP s, 0 < s ≤ 1, in connection with the following known question in the geometric theory of operators: under which conditions on Banach spaces X and Y and on positive numbers r and p does the p-nuclearity of the second adjoint of a continuous operator T from X to Y imply the p-nuclearity of T? Actually, we give necessary and sufficient conditions under which this question is answered affirmatively. In addition, the corresponding counterexamples are obtained in the maximally strong form. For instance, it is shown (and this statement is a significant strengthening of the previous results of that sort) that there exists a pair of separable Banach spaces Z and W such that the spaces Z ** and W have Schauder bases, while for every p, 1 ≤ p < 2, there is a non-p-nuclear operator from W to Z with a p-nuclear second adjoint. Earlier, in similar examples, the corresponding spaces did not possess even the Grothendieck approximation property. The technique developed in this paper does not allow us to treat the case p > 2. That case will be studied in a forthcoming paper of the author. Bibliography: 11 titles. 相似文献
40.
O. Naumenko 《Journal of Molecular Spectroscopy》2003,221(2):221-226
The very weak water vapor absorption spectrum has been investigated between 9520 and 10 010 cm−1 by intracavity laser absorption spectroscopy based on a vertical external cavity surface emitting laser. The rovibrational assignment performed on the basis of the ab initio calculations of Schwenke and Partridge has allowed for determining 156 new energy levels belonging to a total of 13 vibrational states. The assignment process is detailed. The results are compared with the available databases and discussed in regard of recent investigations by Fourier transform spectroscopy. 相似文献