全文获取类型
收费全文 | 7549篇 |
免费 | 160篇 |
国内免费 | 5篇 |
专业分类
化学 | 4113篇 |
晶体学 | 123篇 |
力学 | 147篇 |
数学 | 1306篇 |
物理学 | 2025篇 |
出版年
2022年 | 73篇 |
2021年 | 115篇 |
2020年 | 102篇 |
2019年 | 94篇 |
2018年 | 134篇 |
2017年 | 149篇 |
2016年 | 253篇 |
2015年 | 199篇 |
2014年 | 234篇 |
2013年 | 454篇 |
2012年 | 352篇 |
2011年 | 410篇 |
2010年 | 280篇 |
2009年 | 252篇 |
2008年 | 214篇 |
2007年 | 231篇 |
2006年 | 170篇 |
2005年 | 151篇 |
2004年 | 129篇 |
2003年 | 116篇 |
2002年 | 132篇 |
2001年 | 89篇 |
2000年 | 95篇 |
1999年 | 100篇 |
1998年 | 93篇 |
1997年 | 86篇 |
1996年 | 100篇 |
1995年 | 79篇 |
1994年 | 83篇 |
1993年 | 88篇 |
1992年 | 78篇 |
1991年 | 79篇 |
1990年 | 86篇 |
1989年 | 75篇 |
1988年 | 69篇 |
1987年 | 95篇 |
1985年 | 88篇 |
1984年 | 78篇 |
1983年 | 87篇 |
1982年 | 91篇 |
1981年 | 83篇 |
1980年 | 79篇 |
1979年 | 87篇 |
1978年 | 94篇 |
1977年 | 88篇 |
1976年 | 99篇 |
1975年 | 101篇 |
1974年 | 80篇 |
1968年 | 68篇 |
1966年 | 68篇 |
排序方式: 共有7714条查询结果,搜索用时 15 毫秒
951.
Pontecorvo neutrino oscillations are discussed in the case of Dirac as well as Majorana neutrino mass terms. We prove that none of the possible experiments on neutrino oscillations including those on CP nonconservation, can distinguish between these two possibilities. Oscillations of neutrinos having both Dirac and Majorana mass terms also considered. 相似文献
952.
The longitudinal magnetoresistance of polycrystalline platinum wires has been measured in magnetic fields up to 45 kOe at liquid helium temperatures. The deviations from Kohler's rule found depend on the concentration of quenched-in vacancies, and are interpreted as due to the contribution of single vacancies in platinum to the small angle scattering of electrons. The small-angle scattering may also be responsible for the linear magnetoresistance of platinum in high magnetic fields. 相似文献
953.
954.
955.
956.
957.
A convenient, 40% overall yield synthesis of 2,3,17β-triacetoxy-1,3,5(10)-estratriene is described, which involves epoxidation of 19-nortestosterone and subsequent acetylation, lead tetra-acetate acetoxylation of the so-formed 17β-acetoxy-4β,5-epoxy-5β-estran-3-one, and aromatization of ring A, by means of acidic alumina, of the resulting 2α and 2β epimers of 2,17β-diacetoxy-4β,5-epoxy-5β-estran-3-one. 相似文献
958.
959.
B. Kojić-Prodić M. Tonković O. Hadžija V. Kovač 《Analytical and bioanalytical chemistry》1976,279(5):359-362
For the cyanide determination in waste waters containing more than 2.5×10?6 Mol of CN?/l a conductometric method has been proposed. The sulphuric acid containing samples were distilled and the obtained HCN was passed into a 5×10?4 Mol/l AgNO3 solution, of which the conductivity was measured. The method offers the possibility of a precise observation of the completion of the HCN distillation and also the direct measurement of the cyanide concentration by the change of conductivity. The analysis time is about 40 min. 相似文献
960.
M. Chvojka V. Hermoch B. Králiková J. Krása L. Láska K. Mašek J. Musil S. Polák K. Rohlena J. Schmiedberger J. Skála J. Sulek 《Czechoslovak Journal of Physics》1988,38(12):1337-1356
The photodissociation iodine laser system PERUN I is described. The laser generates and amplifies the subnanosecond pulse with the energy about 80 J of the fundamental wavelength 1·315 μm and beam diameter 10 cm. The physical principles of this type of the high power laser are briefly explained and the laser system and its characteristics are described from the physical and technical point of view. Special attention is paid to the realization of such system with the slow optical pumping (≈300 μs). 相似文献