全文获取类型
收费全文 | 77698篇 |
免费 | 561篇 |
国内免费 | 112篇 |
专业分类
化学 | 41307篇 |
晶体学 | 1261篇 |
力学 | 3282篇 |
综合类 | 1篇 |
数学 | 7827篇 |
物理学 | 24693篇 |
出版年
2022年 | 630篇 |
2021年 | 871篇 |
2020年 | 965篇 |
2019年 | 1105篇 |
2018年 | 1598篇 |
2017年 | 1688篇 |
2016年 | 2149篇 |
2015年 | 1022篇 |
2014年 | 1722篇 |
2013年 | 3271篇 |
2012年 | 2900篇 |
2011年 | 3277篇 |
2010年 | 2636篇 |
2009年 | 2634篇 |
2008年 | 3001篇 |
2007年 | 2873篇 |
2006年 | 2771篇 |
2005年 | 2436篇 |
2004年 | 2241篇 |
2003年 | 2075篇 |
2002年 | 2136篇 |
2001年 | 2237篇 |
2000年 | 1623篇 |
1999年 | 1252篇 |
1998年 | 1125篇 |
1997年 | 1036篇 |
1996年 | 891篇 |
1995年 | 831篇 |
1994年 | 811篇 |
1993年 | 811篇 |
1992年 | 864篇 |
1991年 | 933篇 |
1990年 | 877篇 |
1989年 | 905篇 |
1988年 | 816篇 |
1987年 | 768篇 |
1986年 | 739篇 |
1985年 | 864篇 |
1984年 | 961篇 |
1983年 | 818篇 |
1982年 | 834篇 |
1981年 | 746篇 |
1980年 | 701篇 |
1979年 | 768篇 |
1978年 | 891篇 |
1977年 | 914篇 |
1976年 | 809篇 |
1975年 | 776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 31 毫秒
41.
V. I. Verkhoturov O. S. Grafodatskii V. I. Simanchuk A. V. Kargapol'tsev 《Russian Physics Journal》1993,36(9):865-869
Experimental results are presented on acoustic probing of electric fields in solid insulators. An experimental apparatus and methods are described for acoustic measurements of the bulk space charge density and electric field strength in solid insulators. The sensitivity and spatial resolution of the acoustic probe technique are determined.Institute of Introscopy Research, Polytechnical University, Tomsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 62–67, September, 1993. 相似文献
42.
We study spectral properties of discrete Schrödinger operators with potentials obtained via dimerization of a class of aperiodic sequences. It is shown that both the nature of the autocorrelation measure of a regular sequence and the presence of generic (full probability) singular continuous spectrum in the hull of primitive and palindromic (four block substitution) potentials are robust under dimerization. Generic results also hold for circle potentials. We illustrate these results with numerical studies of the quantum mean square displacement as a function of time. The numerical techniques provide a very fast algorithm for the time evolution of wave packets. 相似文献
43.
The changes in the magnetization of yttrium iron garnet (YIG) when irradiated by a pulsed neodymium laser beam with wavelength
λ=1.06 μm are investigated. Measurements are performed in the temperature range from 100 K to 600 K in various external magnetic
fields. YIG single crystals grown along the crystallographic (100), (110), and (111) directions are chosen so that the external
anisotropy of the indicated processes can be determined. Characteristic temperature intervals dominated by different mechanisms
of variation of the magnetization under the influence of a laser pulse are discussed.
Fiz. Tverd. Tela (St. Petersburg) 39, 1263–1266 (July 1997) 相似文献
44.
45.
I. V. Ukrainets S. G. Taran O. V. Gorokhova P. A. Bezuglyi A. V. Turov 《Chemistry of Heterocyclic Compounds》1994,30(2):204-207
In a solution of DMF, 2-carbethoxymethyl-4H-3,1-benzoxazin-4-one reacts with primarily aromatic amines basically with the formation of the corresponding 2-carbethoxymetlzyl-3-arylquinazolin-4(3H)-ones. Possible mechanisms of these chemical transformations are reported and discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 225–228, February, 1994. Original article submitted June 28, 1993. 相似文献
46.
47.
The electron-impact mass spectra of a number of phenylpropanoids and iridoid glycosides containing a phenylethanoid fragment in their structure have been studied. This has revealed features of the formation of fragments of 4-hydroxyphenylethyl and 3,4-dihydroxyphenylethyl alcohols and also of fragments of phenylethylamine and indolylethylamine derivatives present in the structures of the compounds investigated. 相似文献
48.
49.
50.
M. S. Tashmukhamedov O. K Zakirova Sh. Ya. Mirzaakhmedov Sh. I. Salikhov I. T. Yakubov M. M. Rakhimov 《Chemistry of Natural Compounds》1994,30(1):97-100
Phospholipase A2 has been isolated fromthe venom of he Central Asian green toad Bufo viridis in the electroophoretically homogeneous state for the first time by biospecific absorption chromatography. The affinity sorbent used was Affi-Gel 10 with covalently bound phosphatidylserine (PDS). The chemical inertness of the bound PDS to the hydrolytic action of phospholipase A2 and its high tendency to form biospecific complexes have been shown. Some biochemical characteristics of the enzyme isolated have been studied: influence of the pH and of the Ca2+ concentration and dependence of activity on substrate concentration.A. S. Sadykov Institute of Bioorganic Chemistry, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax 627071. Tashkent State University, fax 462472. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 105–109, January–February, 1994. 相似文献