全文获取类型
收费全文 | 53699篇 |
免费 | 5099篇 |
国内免费 | 3463篇 |
专业分类
化学 | 35262篇 |
晶体学 | 547篇 |
力学 | 3219篇 |
综合类 | 191篇 |
数学 | 7266篇 |
物理学 | 15776篇 |
出版年
2023年 | 623篇 |
2022年 | 1082篇 |
2021年 | 1325篇 |
2020年 | 1559篇 |
2019年 | 1558篇 |
2018年 | 1412篇 |
2017年 | 1295篇 |
2016年 | 2089篇 |
2015年 | 1755篇 |
2014年 | 2177篇 |
2013年 | 3001篇 |
2012年 | 3758篇 |
2011年 | 3910篇 |
2010年 | 2814篇 |
2009年 | 2630篇 |
2008年 | 2930篇 |
2007年 | 2796篇 |
2006年 | 2454篇 |
2005年 | 2077篇 |
2004年 | 1700篇 |
2003年 | 1372篇 |
2002年 | 1343篇 |
2001年 | 1012篇 |
2000年 | 868篇 |
1999年 | 890篇 |
1998年 | 726篇 |
1997年 | 733篇 |
1996年 | 738篇 |
1995年 | 618篇 |
1994年 | 536篇 |
1993年 | 511篇 |
1992年 | 510篇 |
1991年 | 472篇 |
1990年 | 467篇 |
1989年 | 424篇 |
1988年 | 321篇 |
1987年 | 367篇 |
1986年 | 330篇 |
1985年 | 381篇 |
1984年 | 350篇 |
1979年 | 319篇 |
1978年 | 343篇 |
1977年 | 328篇 |
1976年 | 417篇 |
1975年 | 376篇 |
1974年 | 397篇 |
1973年 | 402篇 |
1972年 | 374篇 |
1971年 | 332篇 |
1970年 | 321篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
201.
在物理教学中渗透STS教育 总被引:2,自引:0,他引:2
1 STS的含义 STS是英文单词科学、技术、社会(science、Technology、Society)词头的缩略语.它是一门研究科学、技术和社会关系的交叉学科,而且是一门应用性很强的实践学科.它体现了一种新的价值观、新的科学观、新的教育观和新的社会观. 相似文献
202.
Testing exponentiality against a class of alternatives which includes the RNBUE distributions based on the empirical laplace transform 总被引:1,自引:0,他引:1
S. G. Meintanis Ya. Yu. Nikitin A. V. Tchirina 《Journal of Mathematical Sciences》2007,145(2):4871-4879
A scale-free test for exponentiality is proposed which is consistent within an extended set of models, including, but not
limited to, the “renewal new better than used in expectation” (RNBUE) class of life distributions. The limiting null distribution of the test statistics is derived, and the approximate local
Bahadur efficiency is calculated for several families of alternatives. Finite-sample properties of the proposed procedures
are investigated via simulation. Bibliography: 24 titles.
__________
Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 339, 2006, pp. 63–77. 相似文献
203.
A. Ya. Braginskii 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(2):181-186
For the case of a phase transition into a macroscopically inhomogeneous state described by the order parameter (OP) that is characterized by a multiarm star of a vector {ki}, a method for compensating the spatial variation in all star arms ki is proposed. To this end, a unified tensor field (OP connectivity) is considered, which is interpreted as a stress field potential. The OP-connectivity interaction is described by the phenomenological dislocation charge. Alternative ways of physical interpretation of the OP connectivity are discussed. 相似文献
204.
205.
Xiaowei Sun Zijiang Liu Qifeng Chen Chengwei Wang 《Journal of Physics and Chemistry of Solids》2007,68(2):249-255
Molecular dynamics (MD) method is used to investigate the behavior of the pressure-volume-temperature (P-V-T) relationship, lattice constant and thermal expansivity for ZnO with rock-salt structure at high pressures and temperatures. The interionic potential is taken to be the sum of pair-wise additive Coulomb, van der Waals attraction, and repulsive interactions. The isothermal and isobaric properties are discussed from the corresponding P-V-T relationship, and it is shown that the MD simulation is successful in reproducing the measured volumes of ZnO over a wide range of temperature and pressure. Meanwhile, the equations of state parameters including lattice constant, linear thermal expansion coefficient, and isothermal bulk modulus are calculated and compared with the available experimental data and the latest theoretical results. At an extended pressure and temperature range, P-V-T relationship, lattice constant, and linear thermal expansion coefficient have been predicted. The structural and thermodynamic properties of ZnO with rock-salt structure are summarized in the pressure 0-100 GPa ranges and the temperature up to 3100 K. 相似文献
206.
Ya. A. Éyubov 《International Applied Mechanics》1991,27(1):48-55
Azerbaidzhan Institute of Construction Engineering, Baku. Translated from Prikladnaya Mekhanika, Vol. 27, No. 1, pp. 55–64, January, 1991. 相似文献
207.
B. Sun Yu. A. Litvinov P. M. Walker K. Beckert P. Beller F. Bosch D. Boutin C. Brandau L. Chen C. Dimopoulou H. Geissel R. Knöbel C. Kozhuharov J. Kurcewicz S. A. Litvinov M. Mazzocco J. Meng C. Nociforo F. Nolden W. R. Plass C. Scheidenberger M. Steck H. Weick M. Winkler 《The European Physical Journal A - Hadrons and Nuclei》2007,31(3):393-394
A new long-lived isomeric state in the near proton dripline nucleus 125Ce has been identified with Schottky mass spectrometry at GSI. The excitation energy E
* = 103(12)keV and the decay time of 193(1)s have been obtained from a single stored fully ionized 125m
Ce58+ ion. The data implies an E3 transition and a 1/2+ assignment for the spin of the isomer. 相似文献
208.
V. Ya. Popkova L. E. Vinogradova L. A. Leites V. K. Osmanov 《Russian Chemical Bulletin》1991,40(10):2075-2078
The reaction of ammonia with 2-chloroperfluoro-1-cyclohexene-1-thiocyanate leads to 2-amino-7-iminoperfluoro-4,5,6-trihydrobenzo-1,3-thiazole (II) due to intramolecular heterocyclization in the Thorpe reaction with the concurrent exoiminization. Analysis of the IR spectra of (II) in CCl4 and in the solid phase indicated that molecules of (II) in the crystal form hydrogen-bonded centrosymmetric dimers (D), which are in equilibrium with free molecules of (II) in solution.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2366–2370, October, 1991.The authors express their gratitude to D. I. Zagorevskii for taking the mass spectrum of (II) and to L. S. German for a useful discussion of this work. 相似文献
209.
It is shown how, with the help of approximate integral manifolds, to solve the reduction problem in stability theory in the nonsingular critical case. A generalization of the first fundamental Lyapunov-Malkin theorem in critical cases is obtained.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 43, No. 10, pp. 1324–1329, October, 1991. 相似文献
210.
Average Atom Model in Hot Plasmas 总被引:4,自引:2,他引:2
Average Atom Model in Hot PlasmasAverageAtomModelinHotPlasmas¥YuanJianhui;SunYongsheng;ZhengShaotang(InstituteofAppliedPhysic... 相似文献