全文获取类型
收费全文 | 396517篇 |
免费 | 3141篇 |
国内免费 | 1197篇 |
专业分类
化学 | 201373篇 |
晶体学 | 6579篇 |
力学 | 19520篇 |
综合类 | 11篇 |
数学 | 45171篇 |
物理学 | 128201篇 |
出版年
2020年 | 3451篇 |
2019年 | 4109篇 |
2018年 | 5650篇 |
2017年 | 5592篇 |
2016年 | 7799篇 |
2015年 | 4330篇 |
2014年 | 7446篇 |
2013年 | 17164篇 |
2012年 | 13066篇 |
2011年 | 15840篇 |
2010年 | 11851篇 |
2009年 | 11957篇 |
2008年 | 14824篇 |
2007年 | 14743篇 |
2006年 | 13516篇 |
2005年 | 12054篇 |
2004年 | 11437篇 |
2003年 | 10235篇 |
2002年 | 10131篇 |
2001年 | 11507篇 |
2000年 | 8719篇 |
1999年 | 6742篇 |
1998年 | 5685篇 |
1997年 | 5698篇 |
1996年 | 5346篇 |
1995年 | 4821篇 |
1994年 | 4854篇 |
1993年 | 4809篇 |
1992年 | 5221篇 |
1991年 | 5421篇 |
1990年 | 5141篇 |
1989年 | 5160篇 |
1988年 | 5109篇 |
1987年 | 4987篇 |
1986年 | 4776篇 |
1985年 | 6286篇 |
1984年 | 6551篇 |
1983年 | 5305篇 |
1982年 | 5524篇 |
1981年 | 5403篇 |
1980年 | 5163篇 |
1979年 | 5549篇 |
1978年 | 5586篇 |
1977年 | 5660篇 |
1976年 | 5758篇 |
1975年 | 5286篇 |
1974年 | 5255篇 |
1973年 | 5386篇 |
1972年 | 3934篇 |
1971年 | 3425篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
121.
Salimgareeva V. N. Polevoi R. M. Kolesov S. V. Ostakhov S. S. Ponomareva V. A. Leplyanin G. V. 《Russian Journal of Applied Chemistry》2003,76(5):804-808
The luminescence and scintillation properties of poly(methyl methacrylate) containing 1,1,3-trimethyl-3-phenylindan were studied. 相似文献
122.
L. Villa P. D' Agati C. Mansueto C. Pellerito M. Scopelliti T. Fiore L. Nagy L. Pellerito 《应用有机金属化学》2003,17(2):106-112
Ascidia malaca gametes before fertilization incubated in 10?5 or 10?7 M solutions of tributyltin(IV) chloride, TBTCl, for 3 h appear highly damaged under transmission electron microscopy observation. Also, the fertilization process is affected by the compound: the damaged spermatozoa are present in the vitelline coat and the egg does not cleave. An increase of microbodies, structurally similar to peroxisomes, have been detected in the egg peripheral cytoplasm, probably in relation to their role in alleviating damage to some cellular components. The results have shown that the reproduction of ascidians under unfavourable environmental conditions is prevented. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
123.
H. Okumura T. Takahagi N. Nagai S. Shingubara 《Journal of Polymer Science.Polymer Physics》2003,41(17):2071-2078
The structural change in the depth direction of a polyimide (UPILEX‐S) film treated in alkaline solution, which was a representative surface treatment used to form a seed layer for plating and to improve the adhesive strength, was analyzed by means of micro Fourier transform infrared attenuated total reflection (FTIR‐ATR) line analysis with gradient shaving preparation. The polyimide film was treated with KOH. The imide ring opened through the alkaline treatment, and the amide structure and carboxylic acid salt were formed. The attainment depth of this structural change was almost proportional to the treatment time, and it reached about 8 μm after a 30‐min treatment. The degree of structural change through the alkaline treatment was almost constant after it reached a considerably degraded stage, and the chemically changed region penetrated into the inner part of the film from the surface. An intermediate layer before the final degraded stage appeared in the treated layer, and its thickness increased with the treatment time. The region that was changed chemically by the alkaline treatment progressed to the inner part simultaneously and continuously as the treatment time increased. The combined use of gradient shaving preparation and micro FTIR‐ATR line analysis was found to be extremely effective for the depth profiling of organic materials. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2071–2078, 2003 相似文献
124.
125.
126.
127.
A. N. Zinoviev 《Journal of Mathematical Sciences》2004,124(1):4806-4821
The generalized Hilbert symbol in a cyclotomic extension of an absolutely unramified higher local field of characteristic 0 with a perfect last residue field of characteristic p > 2 is considered. Generalized Artin–Hasse and Iwasawa formulas are derived from an explicit Kummer Type Vostokov formula. Bibliography: 13 titles. 相似文献
128.
A semiclassical theory of electromagnetically induced transparency in a Bose-Einstein condensate is considered. A nonlinear Schrödinger equation that describes the interaction of the Bose-Einstein condensate with an electromagnetic field is derived. An analysis of the obtained solutions to this equation demonstrates a decrease in the group velocity of the light pulse. 相似文献
129.
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
130.
The projection approach is applied to construct and investigate an operator-difference scheme for fluid dynamics in Lagrangean variables which has first-order local approximation in the axisymmetric case near the symmetry axis. The scheme also has operator properties that make it suitable for rederiving and substantiating previous results, methods, and algorithms. 相似文献