全文获取类型
收费全文 | 279932篇 |
免费 | 3208篇 |
国内免费 | 923篇 |
专业分类
化学 | 149257篇 |
晶体学 | 4808篇 |
力学 | 11561篇 |
综合类 | 7篇 |
数学 | 30963篇 |
物理学 | 87467篇 |
出版年
2018年 | 2541篇 |
2017年 | 2569篇 |
2016年 | 4311篇 |
2015年 | 2784篇 |
2014年 | 4302篇 |
2013年 | 11946篇 |
2012年 | 8681篇 |
2011年 | 10704篇 |
2010年 | 7405篇 |
2009年 | 7179篇 |
2008年 | 9872篇 |
2007年 | 9831篇 |
2006年 | 9499篇 |
2005年 | 8831篇 |
2004年 | 8053篇 |
2003年 | 7257篇 |
2002年 | 7087篇 |
2001年 | 8104篇 |
2000年 | 6118篇 |
1999年 | 4847篇 |
1998年 | 4104篇 |
1997年 | 4022篇 |
1996年 | 3826篇 |
1995年 | 3662篇 |
1994年 | 3458篇 |
1993年 | 3359篇 |
1992年 | 3821篇 |
1991年 | 3730篇 |
1990年 | 3631篇 |
1989年 | 3582篇 |
1988年 | 3584篇 |
1987年 | 3592篇 |
1986年 | 3378篇 |
1985年 | 4494篇 |
1984年 | 4708篇 |
1983年 | 4021篇 |
1982年 | 4416篇 |
1981年 | 4105篇 |
1980年 | 4132篇 |
1979年 | 4267篇 |
1978年 | 4401篇 |
1977年 | 4265篇 |
1976年 | 4316篇 |
1975年 | 4159篇 |
1974年 | 4021篇 |
1973年 | 4373篇 |
1972年 | 2779篇 |
1971年 | 2233篇 |
1968年 | 2202篇 |
1967年 | 2160篇 |
排序方式: 共有10000条查询结果,搜索用时 703 毫秒
111.
Radiophysics and Quantum Electronics - We consider whether it is possible in principle to retrieve the key parameters of the mixed layer in the upper ocean (its thickness, bulk eddy viscosity and... 相似文献
112.
113.
114.
N. I. Golovina G. N. Nechiporenko G. G. Nemtsev G. P. Dolganova V. P. Roshchupkin D. B. Lempert G. B. Manelis 《Russian Journal of Applied Chemistry》2007,80(1):24-30
Methods for phase stabilization of ammonium nitrate were sought for in order to considerably expand the application area of this oxidizing agent in various-purpose self-combustible formulations, including that in a new generation of gas-generating formulations for automobile air bags. New methods for stabilization of ammonium nitrate were studied and, in particular, a search was made for organic compounds that can stabilize ammonium nitrate even at their low content. The mechanism of phase state stabilization of ammonium nitrate by compounds of this kind was examined. 相似文献
115.
W. L. Liang B. K. A. Ngoi L. E. N. Lim K. Venkatakrishnan C. W. Hee 《Optics & Laser Technology》2003,35(4):285-290
In this paper, integration of interference phenomenon into femtosecond laser micromachining was reported as the femtosecond laser pulses were reshaped spatially to perform ablation. The generation of circular interference pattern was demonstrated by overlapping infrared femtosecond laser pulses. The interference pattern was subsequently focused on a copper substrate to ablate microstructures of concentric circular rings. The present technique is expected to open up new applications in the areas of rapid fabrication of micro-Fresnel lenses, hybrid microlenses and lens arrays. 相似文献
116.
Demixing during film casting of blends of polystyrene, polymethylmethacrylate, and a symmetric diblock copolymer of styrene and methylmethacrylate is discussed. The concentration fluctuations in the homogeneous solutions were calculated in mean field approximation. The structures in the homogeneous and demixed solutions and in the dry films were measured by small-angle x-ray scattering, and the morphologies of the dry films were characterized by transmission electron microscopy. The structure of the dry blends is evidently already pre-formed in solution. 相似文献
117.
118.
ON A PAIR OF NON-ISOMETRIC ISOSPECTRAL DOMAINS WITH FRACTAL BOUNDARIES AND THE WEYL-BERRY CONJECTURE
ONAPAIROFNONISOMETRICISOSPECTRALDOMAINSWITHFRACTALBOUNDARIESANDTHEWEYLBERRYCONJECTURESLEEMAN,B.D.CHENHUAManuscriptrec... 相似文献
119.
120.
P. Seelig A. Dax S. Faber M. Gerlach G. Huber T. Kühl D. Marx P. Merz W. Quint F. Schmitt H. Winter M. Würtz 《Hyperfine Interactions》1998,114(1-4):135-139
The investigation of the 1s HFS provides a good possibility for testing QED effects in a combination of a strong electric
and magnetic field. Here, we report about the laserspectroscopic measurements of the ground state hyperfine splitting in 207Pb81+. To handle this M1-transition in the infrared optical regime with its long lifetime, we developed a new detection technique
using a bunched ion beam. For the observation of fluorescence light, a new mirror system is adapted to the emission characteristics
from an ion beam at relativistic velocities.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献