全文获取类型
收费全文 | 261377篇 |
免费 | 1250篇 |
国内免费 | 688篇 |
专业分类
化学 | 116353篇 |
晶体学 | 3456篇 |
力学 | 16099篇 |
综合类 | 7篇 |
数学 | 53585篇 |
物理学 | 73815篇 |
出版年
2020年 | 1954篇 |
2019年 | 2433篇 |
2018年 | 13773篇 |
2017年 | 13659篇 |
2016年 | 10300篇 |
2015年 | 2832篇 |
2014年 | 4031篇 |
2013年 | 7718篇 |
2012年 | 9571篇 |
2011年 | 17282篇 |
2010年 | 11329篇 |
2009年 | 11801篇 |
2008年 | 13176篇 |
2007年 | 15201篇 |
2006年 | 6130篇 |
2005年 | 6529篇 |
2004年 | 6550篇 |
2003年 | 6519篇 |
2002年 | 5672篇 |
2001年 | 5299篇 |
2000年 | 4048篇 |
1999年 | 3045篇 |
1998年 | 2846篇 |
1997年 | 2639篇 |
1996年 | 2510篇 |
1995年 | 2205篇 |
1994年 | 2120篇 |
1993年 | 2176篇 |
1992年 | 2161篇 |
1991年 | 2468篇 |
1990年 | 2372篇 |
1989年 | 2455篇 |
1988年 | 2328篇 |
1987年 | 2359篇 |
1986年 | 2192篇 |
1985年 | 2716篇 |
1984年 | 2722篇 |
1983年 | 2369篇 |
1982年 | 2424篇 |
1981年 | 2323篇 |
1980年 | 2126篇 |
1979年 | 2444篇 |
1978年 | 2591篇 |
1977年 | 2667篇 |
1976年 | 2750篇 |
1975年 | 2557篇 |
1974年 | 2479篇 |
1973年 | 2664篇 |
1972年 | 2173篇 |
1971年 | 1983篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
901.
V. I. Ryazanov 《Ukrainian Mathematical Journal》1992,44(10):1292-1298
A positive answer is given to the Reich-Walczak problem relative to conformality in the Belinskii-Lavrent'ev sense of quasiconformal mappings at a point in the case of an arbitrary modulus of the complex characteristic and under an appropriate selection of its argument.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 44, No. 10, pp. 1406–1411, October, 1992. 相似文献
902.
I. I. Antakov M. A. Moiseev E. V. Sokolov E. V. Zasypkin 《International Journal of Infrared and Millimeter Waves》1994,15(5):873-887
Using self-consistent field theory, the interaction of electron flow with HF fields in a gyroklystron has been analized. Optimal parameters of its output cavity corresponding to the maximum efficiency have been found. Experimental study of dependence of the efficiency on Q-factor and length of the output cavity has been carried out. The results of simulation are in good qualitative agreement with experimental data. 相似文献
903.
904.
Monte Carlo simulations have been carried out to study the growth kinetics after a rapid quench of a system with nonconserved order parameter into a steady state characterized by a thermal gradient. Both the Allen-Cahn growth law for the average domain size as well as the scaling behavior, typical for systems evolving towards equilibrium, are observed. Some aspects of different spinupdating algorithms are briefly discussed. 相似文献
905.
906.
907.
Yu. V. Zhitnikov Yu. I. Zetser 《Journal of Applied Mechanics and Technical Physics》1992,33(6):787-792
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 6, pp. 22–28, November–December, 1992. 相似文献
908.
A general relationship between the volume fraction and the specific interfacial area for averaged dispersed two-phase flows is proposed. This relationship, expressed as a basic set of two scalar evolution equations and two vectorial non-uniformity state equations, is an analytical result obtained by a systematic approach using the derivatives of some generalized functions and a local volume-averaging technique. The proposed set of equations was expressed for measurable macroscopic parameters of the system and has the same generality as the averaged transport equations of two-phase flows. By combination of the basic set of equations, called the averaged topological equations (ATEs), second-order ATEs for the volume fraction were found. The second-order ATEs were expressed both by a Lagrangian formulation and by a Eulerian formulation. The importance and physical meaning of the ATEs developed in this study were clarified within the framework of the theory of kinematic waves. 相似文献
909.
We have undertaken an experimental investigation of the influence of the conditions of barrier discharge implementation such as: the discharge gap value, the type of gas, and the polarity and dielectric permittivity of the dielectric electrode on the value of charge transferred in a micro-discharge. It is shown that the increase in the specific capacitance of the electrodes leads to proportional increase in the transferred charge value, reaching 100–200 nC in a discharge gap 1 mm, in air. In this case the amplitude and duration of a current pulse in the microdischarge reach, respectively, 10 to 15 A and 40 ns. It is also demonstrated that in air with increase in the discharge gap value one can observe a decrease in the efficiency of the ozone synthesis whereas in oxygen there exists a more complicated dependence: the maximum of efficiency is observed at a discharge gap value of 0.7 to 1.0 mm. 相似文献
910.
V.I. Marakhonov N.A. Rogachev E.I. Terukov J.T. Ishkalov I.N. Trapeznikova 《Physica B: Condensed Matter》1991,170(1-4):571-573
Magnetron assisted silane decomposition (MASD) is proposed as a method for deposition of a-Si:H and its alloys. In this method a silane containing gas mixture is passed through the magnetron plasma near a target and decomposed there. The deposition rate in the case of the c-Si target is increased 3 times compared to magnetron sputtering and film properties are changed. a-SiSn:H is obtained with a Sn target. 相似文献