全文获取类型
收费全文 | 23178篇 |
免费 | 434篇 |
国内免费 | 302篇 |
专业分类
化学 | 12505篇 |
晶体学 | 220篇 |
力学 | 1631篇 |
综合类 | 17篇 |
数学 | 3775篇 |
物理学 | 5766篇 |
出版年
2021年 | 253篇 |
2020年 | 337篇 |
2019年 | 417篇 |
2018年 | 538篇 |
2017年 | 499篇 |
2016年 | 687篇 |
2015年 | 395篇 |
2014年 | 614篇 |
2013年 | 1186篇 |
2012年 | 783篇 |
2011年 | 821篇 |
2010年 | 785篇 |
2009年 | 740篇 |
2008年 | 756篇 |
2007年 | 759篇 |
2006年 | 603篇 |
2005年 | 524篇 |
2004年 | 504篇 |
2003年 | 513篇 |
2002年 | 553篇 |
2001年 | 506篇 |
2000年 | 377篇 |
1999年 | 311篇 |
1998年 | 275篇 |
1997年 | 268篇 |
1996年 | 257篇 |
1993年 | 255篇 |
1992年 | 255篇 |
1991年 | 255篇 |
1990年 | 282篇 |
1989年 | 277篇 |
1987年 | 253篇 |
1985年 | 302篇 |
1984年 | 302篇 |
1983年 | 278篇 |
1982年 | 292篇 |
1981年 | 270篇 |
1980年 | 273篇 |
1979年 | 320篇 |
1978年 | 339篇 |
1977年 | 335篇 |
1976年 | 418篇 |
1975年 | 377篇 |
1974年 | 400篇 |
1973年 | 412篇 |
1972年 | 377篇 |
1971年 | 337篇 |
1970年 | 318篇 |
1969年 | 303篇 |
1968年 | 263篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
131.
Savos'kin M. V. Yaroshenko A. P. Shologon V. I. Galushko L. Ya. 《Russian Journal of Applied Chemistry》2003,76(7):1179-1181
Petroleum sorption on expanded graphite prepared from residual graphite hydrosulfate at 300-900°C was studied as influenced by pretreatment of the sorbent with water. 相似文献
132.
A deflecting system formed by two parallel-plate capacitors on opposite sides of an optoelectronic element that alters the
energy of a beam of charged particles, is calculated numerically. The conditions for correcting the chromatic beam spreading
in the plane of the target are found. Good agreement with the results of an approximate analytical calculation is demonstrated.
Zh. Tekh. Fiz. 67, 86–88 (December 1997) 相似文献
133.
S. Ya. Khavinson 《Journal of Mathematical Sciences》1993,63(2):275-290
The paper is devoted to the theory of factorization of univalent analytic functions on a compact Riemann surface with boundary. The main component of the theory is a new method for the removal of the periods of certain functions (the natural analogues of the Schwarz integral and Blaschke products) along the boundary curves and bundle sections.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova Akademii Nauk SSSR, Vol. 170, pp. 285–313, 1989. 相似文献
134.
A. V. Shapovalov I. V. Shirokov Ya. V. Lisitsyn V. I. Firstov 《Russian Physics Journal》1995,38(2):209-212
D'alambert's equation is used as an example to study the possibilities of a new method of exactly integrating systems of linear differential equations — the method of noncommutative integration (NI). The results confirm that use of the NI is equivalent to complete separation of the variables in the case of four-dimensional subalgebras of conformal algebra. However, the method does simplify determination of the exact solution in this instance.Tomsk University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 120–124, February, 1995. 相似文献
135.
Electron-positron production processes occurring in the interaction of 1018–1020 W/cm2 laser radiation with high-Z targets are examined. Computational results are presented for the pair production and the positron yield from the target
with allowance for the contribution of pair production processes due to electrons and bremsstrahlung photons. Monte Carlo
simulations using the PRIZMA code confirm the estimates obtained. The possible positron yield from high-Z targets irradiated with 102–103 TW laser radiation is estimated to be 109–1011.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 4, 239–244 (25 February 1998) 相似文献
136.
The phase composition and the temperature dependence of the magnetization of the Er0.45Ho0.55Fe2 compound in coarse-grained, microcrystalline, and submicrocrystalline states are investigated experimentally. It is found
that, upon heating under vacuum, the Er0.45Ho0.55Fe2 microcrystalline powder with a crystalline grain size of ∼1 μm undergoes decomposition into pure iron and rare-earth (erbium
and holmium) oxides and nitrides at a temperature of 500 K. The changes observed in the phase composition of the microcrystalline
powder due to annealing are confirmed by x-ray diffraction analysis. Heating of the Er0.45Ho0.55Fe2 submicrocrystalline sample leads to a partial change in the phase composition. The phase composition of a large crystal (∼1
mm in size) remains unchanged upon heating to 1080 K. It is shown that the thermal stability of the Er0.45Ho0.55Fe2 compound depends on the crystalline grain size.
__________
Translated from Fizika Tverdogo Tela, Vol. 44, No. 6, 2002, pp. 1060–1063.
Original Russian Text Copyright ? 2002 by Mulyukov, Sharipov, Korznikova. 相似文献
137.
138.
We discuss general questions about the choice of optimization criteria for the stressed state of thermoelastic shells taking account of the functional measures of the space-time variability of its characteristics. The efficiency of the proposed approach is illustrated using the example of the solution of a problem for an axisymmetrically heated cylindrical shell.Translated fromMatematicheskie Metody i Fiziko-Mekhanicheskie Polya, Issue 27, 1988, pp. 11–18. 相似文献
139.
140.
L. P. Eksperiandova A. I. Fedorov Ya. N. Makarovskaya 《Journal of Analytical Chemistry》2007,62(12):1163-1166
A series of quasi-solid emitters is proposed for the X-ray fluorescence determination of bromine in different bromine-containing compounds. It is shown that sucrose-based glasses are the best emitters for analyzing alkali solutions of halogenated organic compounds, saccharose-based glasses and polymer films are best for analyzing powder samples, and organic gels offer most promise for analyzing liquid (at normal conditions) samples. It is noted that the proposed method can expand the possibilities of commercially produced element analyzers, which are currently intended for determining only C, H, O, N, and S in organic compounds and cannot be used for determining halogens. 相似文献