全文获取类型
收费全文 | 1329篇 |
免费 | 20篇 |
国内免费 | 17篇 |
专业分类
化学 | 832篇 |
晶体学 | 9篇 |
力学 | 41篇 |
数学 | 189篇 |
物理学 | 295篇 |
出版年
2022年 | 9篇 |
2021年 | 15篇 |
2020年 | 14篇 |
2017年 | 10篇 |
2016年 | 20篇 |
2015年 | 16篇 |
2014年 | 16篇 |
2013年 | 67篇 |
2012年 | 35篇 |
2011年 | 66篇 |
2010年 | 45篇 |
2009年 | 31篇 |
2008年 | 43篇 |
2007年 | 63篇 |
2006年 | 48篇 |
2005年 | 53篇 |
2004年 | 48篇 |
2003年 | 38篇 |
2002年 | 44篇 |
2001年 | 32篇 |
2000年 | 36篇 |
1999年 | 35篇 |
1998年 | 12篇 |
1997年 | 20篇 |
1996年 | 32篇 |
1995年 | 19篇 |
1994年 | 18篇 |
1993年 | 32篇 |
1992年 | 12篇 |
1991年 | 20篇 |
1990年 | 26篇 |
1989年 | 19篇 |
1988年 | 17篇 |
1987年 | 22篇 |
1986年 | 16篇 |
1985年 | 25篇 |
1984年 | 28篇 |
1983年 | 15篇 |
1982年 | 16篇 |
1981年 | 18篇 |
1980年 | 18篇 |
1979年 | 18篇 |
1978年 | 11篇 |
1977年 | 12篇 |
1976年 | 13篇 |
1975年 | 14篇 |
1974年 | 10篇 |
1973年 | 11篇 |
1972年 | 12篇 |
1968年 | 9篇 |
排序方式: 共有1366条查询结果,搜索用时 15 毫秒
71.
72.
73.
A subset of the -dimensional torus is called a set of uniqueness, or -set, if every multiple trigonometric series spherically converging to outside vanishes identically. We show that all countable sets are -sets and also that sets are -sets for every . In particular, , where is the Cantor set, is an set and hence a -set. We will say that is a -set if every multiple trigonometric series spherically Abel summable to outside and having certain growth restrictions on its coefficients vanishes identically. The above-mentioned results hold also for sets. In addition, every -set has measure , and a countable union of closed -sets is a -set.
74.
75.
76.
77.
The reaction \documentclass{article}\pagestyle{empty}\begin{document}${\rm Br} + {\rm CH}_3 {\rm CHO}\buildrel1\over\rightarrow{\rm HBr} + {\rm CH}_3 {\rm CO}$\end{document} has been studied by VLPR at 300 K. We find k1 = 2.1 × 1012 cm3/mol s in excellent agreement with independent measurements from photolysis studies. Combining this value with known thermodynamic data gives k-1 = 1 × 1010 cm3/mol s. Observations of mass 42 expected from ketene suggest a rapid secondary reaction: in which step 2 is shown to be rate limiting under VLPR conditions and k2 is estimated at 1012.6 cm3/mol s from recent theoretical models for radical recombination. It is also shown that 0 ? E1 ? 1.4 kcal/mol using theoretical models for calculation of A1 and is probably closer to the lower limit. Reaction ?1 is negligible under conditions used. 相似文献
78.
Human saliva was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the response to different natural stimuli investigated. Serva Blue R revealed pink/violet-staining proteins ("lumicarmines"). These intensified following stimulation but in an unpredictable and sometimes disproportionate manner, causing pattern changes. This variable response undermines their potential forensic value for suspect identification. 相似文献
79.
R.W. Clifft J.B. Dainton E. Gabathuler L.S. Littenberg R. Marshall S.E. Rock J.C. Thompson D.L. Ward G.R. Brookes 《Physics letters. [Part B]》1976,64(2):213-216
A measurement of backward photoproduction of charged pion pairs on protons is reported. The pion pair mass spectrum shows strong ?° and f production. Data are presented on the u and s dependence for ?O and f, together with the decay polarisation for the ?O. 相似文献
80.
B. Pietrzyk R. Barate P. Bareyre P. Bonamy P. Borgeaud M. David F.X. Gentit G. Laurens Y. Lemoigne G. Villet S. Zaninotti P. Astbury A. Duane G.J. King B.C. Nandi R. Namjoshi D.M. Websdale J. Wiejak T. Marshall 《Physics letters. [Part B]》1982,113(1):105-112
A lepton-pair trigger was used to select a hadronic system in different flavour and colour states: properties of the transformation of this system into hadrons were measured in terms of charge flow, multiplicity distribution, and fragmentation function. It is observed that, while the effects of flavour are clearly seen, the colour degrees of freedom are not observed in the region of low pT. 相似文献