全文获取类型
收费全文 | 886篇 |
免费 | 11篇 |
国内免费 | 2篇 |
专业分类
化学 | 503篇 |
晶体学 | 3篇 |
力学 | 47篇 |
数学 | 64篇 |
物理学 | 282篇 |
出版年
2017年 | 5篇 |
2016年 | 15篇 |
2015年 | 8篇 |
2014年 | 8篇 |
2013年 | 34篇 |
2012年 | 12篇 |
2011年 | 28篇 |
2010年 | 24篇 |
2009年 | 17篇 |
2008年 | 37篇 |
2007年 | 43篇 |
2006年 | 41篇 |
2005年 | 33篇 |
2004年 | 34篇 |
2003年 | 37篇 |
2002年 | 33篇 |
2001年 | 19篇 |
2000年 | 24篇 |
1999年 | 23篇 |
1998年 | 11篇 |
1997年 | 13篇 |
1996年 | 15篇 |
1995年 | 15篇 |
1994年 | 14篇 |
1993年 | 21篇 |
1992年 | 19篇 |
1991年 | 16篇 |
1990年 | 19篇 |
1989年 | 5篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 11篇 |
1985年 | 15篇 |
1984年 | 21篇 |
1983年 | 11篇 |
1982年 | 13篇 |
1981年 | 17篇 |
1980年 | 21篇 |
1979年 | 13篇 |
1978年 | 16篇 |
1977年 | 6篇 |
1976年 | 9篇 |
1975年 | 14篇 |
1974年 | 10篇 |
1973年 | 13篇 |
1972年 | 6篇 |
1971年 | 5篇 |
1970年 | 5篇 |
1969年 | 6篇 |
1935年 | 4篇 |
排序方式: 共有899条查询结果,搜索用时 31 毫秒
61.
Preparation of Stereoregular Isotactic Poly(mandelic acid) through Organocatalytic Ring‐Opening Polymerization of a Cyclic O‐Carboxyanhydride
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Antoine Buchard Dr. David R. Carbery Prof. Matthew G. Davidson Dr. Petya K. Ivanova Dr. Ben J. Jeffery Dr. Gabriele I. Kociok‐Köhn Dr. John P. Lowe 《Angewandte Chemie (International ed. in English)》2014,53(50):13858-13861
Poly(mandelic acid) (PMA) is an aryl analogue of poly(lactic acid) (PLA) and a biodegradable analogue of polystyrene. The preparation of stereoregular PMA was realized using a pyridine/mandelic acid adduct (Py?MA) as an organocatalyst for the ring‐opening polymerization (ROP) of the cyclic O‐carboxyanhydride (manOCA). Polymers with a narrow polydispersity index and excellent molecular‐weight control were prepared at ambient temperature. These highly isotactic chiral polymers exhibit an enhancement of the glass‐transition temperature (Tg) of 15 °C compared to the racemic polymer, suggesting potential future application as high‐performance commodity and biomedical materials. 相似文献
62.
63.
Sharona Sedghani Cohen Vardit Eckhouse Asher A. Friesem Nir Davidson 《Optics Communications》2009,282(9):1861-1866
We show that by coherently combining several solid state lasers it is possible to obtain a single frequency output. This is experimentally demonstrated by coherently combining four Nd:YAG lasers channels, each with a properly chosen cavity length, in order to suppress unwanted longitudinal modes and obtain a single frequency output. We also present a model that accurately predicts and supports out experimental results. 相似文献
64.
The restriction principle is used to implement a realization of the holomorphic representations of SL(2,R) on L
2 (R
+,t
dt) by way of the standard upper half plane realization. The resulting unitary equivalence establishes a correspondence between functions that transform according to the character e–i(2n++1); under rotations and the Laguerre polynomials. The standard recursion relations amongst Laguerre polynomials are derived from the action of the Lie algebra. 相似文献
65.
[reaction: see text] Mucohalic acids (mucochloric acid (1, 3,4-dichloro-5-hydroxy-5H-furan-2-one) and mucobromic acid (2, 3,4-dibromo-5-hydroxy-5H-furan-2-one)) are inexpensive, commercially available starting materials with multiple functional groups. These compounds have been modified by way of reduction followed by Suzuki cross-coupling reactions involving arylboronic acids to afford highly functionalized alpha,beta-unsaturated gamma-butyrolactones in excellent yield. The synthetic utility of these building blocks was effectively demonstrated through preparation of the antiinflammatory drug Vioxx. 相似文献
66.
R. A. Ritchie D. W. von Oertzen N. J. Davidson R. M. Quick H. G. Miller 《Zeitschrift fur Physik C Particles and Fields》1992,55(2):347-351
Hadron gas models have proved successful in predicting particle production in relativistic nucleus-nucleus collisions. The extension of these models to the smaller systems formed in proton-nucleus collisions requires that the finite size of the system be considered. We study two features introduced by the finite size: the need to conserve strangeness and baryon number exactly by performing calculations in the canonical ensemble, and the inclusion of a finite size geometrical correction term in the single particle density of states. We find significant differences between the grand canonical and canonical ensembles and a strong dependence on the baryon number of the system. 相似文献
67.
Richard L. Martin Larry E. McMurchie Ernest R. Davidson 《International journal of quantum chemistry》1978,13(2):161-168
The completeness of a basis set for ethylene is examined relative to its ability to describe transition moments. The double zeta (Dunning contraction) plus polarization plus Rydberg Cartesian Gaussian set does much better for length than for velocity moments. An attempt is made to interpret the transition moment sums for the occupied orbitals. 相似文献
69.
Ohne Zusammenfassung 相似文献
70.
Photo-reductive dehalogenation of aromatic halides to their parent hydrocarbons is stimulated in the presence of electron donors such as di-ethyl sulphide. Evidence is presented for the involvement of radicals ions in these reactions. 相似文献