全文获取类型
收费全文 | 1295篇 |
免费 | 31篇 |
国内免费 | 11篇 |
专业分类
化学 | 972篇 |
晶体学 | 24篇 |
力学 | 26篇 |
数学 | 111篇 |
物理学 | 204篇 |
出版年
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 8篇 |
2019年 | 18篇 |
2018年 | 10篇 |
2017年 | 18篇 |
2016年 | 23篇 |
2015年 | 15篇 |
2014年 | 34篇 |
2013年 | 52篇 |
2012年 | 58篇 |
2011年 | 83篇 |
2010年 | 32篇 |
2009年 | 45篇 |
2008年 | 60篇 |
2007年 | 64篇 |
2006年 | 65篇 |
2005年 | 83篇 |
2004年 | 77篇 |
2003年 | 64篇 |
2002年 | 53篇 |
2001年 | 29篇 |
2000年 | 31篇 |
1999年 | 6篇 |
1998年 | 21篇 |
1997年 | 20篇 |
1996年 | 22篇 |
1995年 | 12篇 |
1994年 | 18篇 |
1993年 | 21篇 |
1992年 | 9篇 |
1991年 | 19篇 |
1990年 | 16篇 |
1989年 | 15篇 |
1988年 | 16篇 |
1987年 | 16篇 |
1986年 | 17篇 |
1985年 | 18篇 |
1984年 | 25篇 |
1983年 | 8篇 |
1982年 | 13篇 |
1981年 | 12篇 |
1980年 | 15篇 |
1979年 | 10篇 |
1978年 | 8篇 |
1977年 | 9篇 |
1975年 | 7篇 |
1974年 | 8篇 |
1973年 | 5篇 |
1963年 | 5篇 |
排序方式: 共有1337条查询结果,搜索用时 15 毫秒
161.
A manifold is described which permits the analysis of less than 1 ml of sample solution. Water- and air-compensation methods for the introduction of the carrier stream into the nebulizer are effective in obtaining sensitive and reproducible measurements of magnesium, but air-compensation gives higher peak responses. 相似文献
162.
163.
164.
An acrylonitrile-styrene copolymer having 51.4 wt % acrylonitrile content was fractionated using dimethylformamide and a toluene–n-propanol mixture as solvent and nonsolvent, respectively. From characterization of the fractions, it is shown that the copolymer was fractionated principally in accordance with composition. The weight distribution curve of the copolymer was expressed as a function of both molecular weight and chemical composition on a two-dimensional contour map. The same plotting technique was applied to a copolymer having nearly the azeotropic composition. 相似文献
165.
An apparatus and the procedure for cellulose acetate isoelectric focusing were refined and optimized for routine use in clinical laboratories. The space in the electrophoretic chamber was minimized to maintain high humidity during the run. The water content of the thin cellulose acetate membranes in the chamber was well controlled during isoelectric focusing and the effect of atmospheric carbon dioxide was also excluded. The temperature of the membranes was kept below 2 degrees C, even under conditions of high electric field strength for faster isoelectric focusing of high-molecular-weight proteins. No special training was required for technicians in clinical laboratories to obtain reproducible isoelectric profiles of human serum proteins. 相似文献
166.
167.
168.
D. L. Adams B. Aas E. Bleszynski M. Bleszynski G. Igo C. Newsom Y. Ohashi G. Pauletta F. Sperisen C. A. Whitten Jr. H. Fujisawa M. GazzalyS. J. Greene K. Jones J. B. McClelland N. TanakaH. Hasai K. IwataniS. Ishimoto S. IsagawaA. MasaikeA. OkihanaS. Okumi 《Nuclear Physics A》1988,480(3-4)
We have measured spin correlation parameters that describe the elastic scattering of 800 MeV polarized protons from an L-type polarized deuteron target at laboratory angles below 20°. The measured parameters include the correlated analyzing powers ASL, ALL and ANLL and the proton spin-transfer coefficients C0L,S, C0L,L, CSL,N, CNL,S, CNL,L and CLL,N. The results are compared with single-scattering predictions based on different phase-shift solutions for the nucleon-nucleon scattering matrix. 相似文献
169.
170.
Energy distributions of π+ produced from 12C by electrons of total energy 195 MeV were measured at various angles. The results show large contributions from transitions leaving the residual nucleus in the ground (1+), first (2+) excited state and states at around 4.5 MeV. The angular distributions of 12C(γ, π+)12B leading to these residual states are deduced from the energy distributions by the unfolding method with the virtual photon theory. Theoretical results with the Helm model and the shell model are compared with the experimental results. Their relative shapes are in good agreement. A better agreement in the absolute value is found for the theoretical results which include the final-state interaction estimated with a pion optical potential. The surface production model shows better agreement with the experimental (γ, π+) cross sections than the volume production model. 相似文献