全文获取类型
收费全文 | 44928篇 |
免费 | 2502篇 |
国内免费 | 4722篇 |
专业分类
化学 | 16698篇 |
晶体学 | 536篇 |
力学 | 2092篇 |
综合类 | 301篇 |
数学 | 4047篇 |
物理学 | 9088篇 |
综合类 | 19390篇 |
出版年
2022年 | 712篇 |
2021年 | 848篇 |
2020年 | 832篇 |
2019年 | 842篇 |
2018年 | 876篇 |
2017年 | 1092篇 |
2016年 | 1173篇 |
2015年 | 1342篇 |
2014年 | 1951篇 |
2013年 | 2371篇 |
2012年 | 2465篇 |
2011年 | 2587篇 |
2010年 | 2652篇 |
2009年 | 2720篇 |
2008年 | 2896篇 |
2007年 | 2744篇 |
2006年 | 2491篇 |
2005年 | 2111篇 |
2004年 | 1788篇 |
2003年 | 1456篇 |
2002年 | 1632篇 |
2001年 | 1551篇 |
2000年 | 1317篇 |
1999年 | 744篇 |
1998年 | 364篇 |
1997年 | 324篇 |
1996年 | 312篇 |
1995年 | 304篇 |
1994年 | 288篇 |
1993年 | 331篇 |
1992年 | 333篇 |
1991年 | 297篇 |
1990年 | 316篇 |
1989年 | 312篇 |
1985年 | 290篇 |
1984年 | 303篇 |
1983年 | 276篇 |
1982年 | 295篇 |
1980年 | 273篇 |
1979年 | 309篇 |
1978年 | 339篇 |
1977年 | 325篇 |
1976年 | 405篇 |
1975年 | 360篇 |
1974年 | 388篇 |
1973年 | 396篇 |
1972年 | 369篇 |
1971年 | 334篇 |
1970年 | 314篇 |
1969年 | 298篇 |
排序方式: 共有10000条查询结果,搜索用时 593 毫秒
171.
Measurement of the First Hyperpolarizability of Substituted Ketene N,S-acetals by Hyper-Rayleigh Scattering in Solution 总被引:1,自引:1,他引:0
MeasurementoftheFirstHyperpolarizabilityofSubstitutedKeteneN,S-acetalsbyHyper-RayleighScatteringinSolutionGAOXingyu;CHENJingb... 相似文献
172.
173.
A. E. Blinov V. E. Blinov A. E. Bondar A. D. Bukin V. R. Groshev S. G. Klimenko G. M. Kolachev A. P. Onuchin V. S. Panin I. Ya. Protopopov A. G. Shamov V. A. Sidorov Yu. I. Skovpen A. N. Skrinsky V. A. Tayursky V. I. Telnov Yu. A. Tikhonov G. M. Tumaikin A. E. Undrus A. I. Vorobiov V. N. Zhilich 《Zeitschrift fur Physik C Particles and Fields》1992,53(1):33-39
The process γγ→π+π? was measured using the detector MD-1 at VEPP-4. The two-photon reactionse + e ?, μ+ μ? and π+ π? pair production were separated using scintillation counters, Cherenkov counters and shower-range chambers. A radiation widthГ γγ(f 2(1270))=3.1±0.35±0.35 keV was obtained. 相似文献
174.
Ya. M. Pelekh 《Ukrainian Mathematical Journal》1992,44(12):1554-1560
A new technique for the construction of numerical methods based on continued fractions is proposed. A characteristic feature of these algorithms is the fact that for certain values of the parameters it is possible to obtain both novel and traditional (explicit and implicit) numerical methods for the solution of the Cauchy problem for ordinary differential equations. Two-sided formulas are proposed by means of which it is possible to obtain on each integration step not only upper and lower approximations to the exact solution, but also information concerning the magnitude of the leading term of the error without the need for additional calculations of the right-hand side of the initial differential equation.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 44, No. 12, pp. 1695–1701, December, 1992. 相似文献
175.
停流—荧光动力学分析法测定痕量钛的研究 总被引:3,自引:1,他引:2
利用自行组装的停流-荧光动力学分析仪,采用停流法汇合流体动力注入技术,研究了钛与3.5-二溴水杨基荧光酮的荧光增强动力学反应性质,讨论了流速、进样时间对方法灵敏度和精密度的影响,提出了一个快速、简便、精确测定钛的分析方法,并用于稀土样品及合成样品中痕量钛的测定.方法检测限为8×10~(-3)ppm,大多数元素的干扰均可用动力学方法消除. 相似文献
176.
The radiative capture of ultracold neutrons traversing thin and thick homogeneous layers of matter is analyzed. The applicability range of the formulas for the probabilities of reflection, transmission, and capture in thick layers (under certain conditions, they admit a simple interpretation—it is often quoted in the literature—that is based on the effective capture cross section, which is in inverse proportion to the velocity of a neutron in matter) is investigated, along with the conditions under which there arises the effective capture cross section. 相似文献
177.
We propose a general method for obtaining Tauberian theorems with remainder for one class of Voronoi summation methods for double sequences of elements of a locally convex, linear topological space. This method is a generalization of the Davydov method of C-points. 相似文献
178.
A. Kh. Passos Morgado Ya. Pivnik Yu. N. Podil'chuk 《International Applied Mechanics》1995,31(11):865-872
Universidade de Beira Interior, Portugal: and S. P. Timoshenko Institute of Mechanics, National Academy of Sciences of the Ukraine, Kiev. Translated from Prikladnaya Mekhanika, Vol. 31. No. 11, pp. 3–10, November, 1995. 相似文献
179.
V. Ya. Eiderman 《Mathematical Notes》1995,57(1):110-112
Translated from Matematicheskie Zametki, Vol. 57, No. 1, pp. 150–153, January, 1995. 相似文献
180.
The influence of a large signal on the characteristics of a small signal near the frequency of the former is experimentally studied for the case of their simultaneous propagation through a resonant transmission line based on backward volume magnetostatic waves. The effects observed are caused by the excitation of spin waves in a ferromagnetic film at different large-signal frequencies and by the back influence of excited spin-wave packets on the amplitude and phase characteristics of the small signal. 相似文献