全文获取类型
收费全文 | 2365篇 |
免费 | 66篇 |
国内免费 | 5篇 |
专业分类
化学 | 1642篇 |
晶体学 | 5篇 |
力学 | 23篇 |
数学 | 227篇 |
物理学 | 539篇 |
出版年
2023年 | 30篇 |
2022年 | 33篇 |
2021年 | 40篇 |
2020年 | 64篇 |
2019年 | 36篇 |
2016年 | 61篇 |
2015年 | 45篇 |
2014年 | 49篇 |
2013年 | 66篇 |
2012年 | 78篇 |
2011年 | 79篇 |
2010年 | 50篇 |
2009年 | 36篇 |
2008年 | 47篇 |
2007年 | 57篇 |
2006年 | 66篇 |
2005年 | 59篇 |
2004年 | 55篇 |
2003年 | 35篇 |
2002年 | 34篇 |
2001年 | 44篇 |
2000年 | 39篇 |
1999年 | 32篇 |
1998年 | 33篇 |
1995年 | 34篇 |
1994年 | 28篇 |
1993年 | 34篇 |
1992年 | 25篇 |
1991年 | 34篇 |
1990年 | 31篇 |
1988年 | 35篇 |
1987年 | 22篇 |
1985年 | 26篇 |
1984年 | 21篇 |
1982年 | 21篇 |
1980年 | 28篇 |
1979年 | 35篇 |
1978年 | 30篇 |
1977年 | 53篇 |
1976年 | 37篇 |
1975年 | 37篇 |
1974年 | 40篇 |
1973年 | 39篇 |
1972年 | 38篇 |
1971年 | 29篇 |
1970年 | 23篇 |
1969年 | 30篇 |
1968年 | 32篇 |
1967年 | 38篇 |
1966年 | 28篇 |
排序方式: 共有2436条查询结果,搜索用时 15 毫秒
1.
Mechanistic Aspects of a Highly Active Dinuclear Zinc Catalyst for the Co‐polymerization of Epoxides and CO2
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Stefan Kissling Peter T. Altenbuchner Dr. Maximilian W. Lehenmeier Dr. Eberhardt Herdtweck Dr. Peter Deglmann Dr. Uwe B. Seemann Prof. Dr. Bernhard Rieger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8148-8157
The dinuclear zinc complex reported by us is to date the most active zinc catalyst for the co‐polymerization of cyclohexene oxide (CHO) and carbon dioxide. However, co‐polymerization experiments with propylene oxide (PO) and CO2 revealed surprisingly low conversions. Within this work, we focused on clarification of this behavior through experimental results and quantum chemical studies. The combination of both results indicated the formation of an energetically highly stable intermediate in the presence of propylene oxide and carbon dioxide. A similar species in the case of cyclohexene oxide/CO2 co‐polymerization was not stable enough to deactivate the catalyst due to steric repulsion. 相似文献
2.
A synthesis of methyl 2-oxo-5-vinyl-tetrahydrofuran-3-carboxylate involving five synthetic steps from commercially available 3,4-dihydroxybutene is reported. 相似文献
3.
4.
5.
It is shown that the appearance of discrete ambiguities in the optical potential of composite particles is caused by the existence of partly Pauli-forbidden states. The given interpretation is tested in the case ofα-58Ni scattering atE α=50.2 MeV where seven different optical potentials give satisfactory agreement with experiment. 相似文献
6.
We show that it is a NP-complete problem to decide whether a finite poset arises as the (Birkhoff) dual of the Frattini sublattice of some finite distributive lattice.This work was supported in part by Swiss NSF grant 20-32644.91. 相似文献
7.
8.
The 351 nm laser-damage thresholds (at 0.7 nm pulse length) of monomeric liquid crystals are reported and results from aromatic-core samples are compared with those from fully saturated systems. The role of π-electron conjugation is examined and identified as the key cause for laser damage. For UV laser compatibility of devices, the damage behaviour of an alignment-layer polymer (nylon 6/6) was also investigated. 相似文献
9.
The three-body Coulomb problem for nuclear clusters is solved numerically for a model below three-body breakup threshold. An orthogonalized multi-channels method is employed. The method allows to check for convergence by considering the norm square of the closed-channels part of the wave function. The numerical results show that convergence can well be achieved on present-day computers. 相似文献
10.
Kochocki JA Allison WW Alner GJ Ambats I Ayres DS Balka LJ Barr GD Barrett WL Benjamin D Border P Brooks CB Cobb JH Cockerill DJ Coover K Courant H Dahlin B DasGupta U Dawson JW Edwards VW Fields TH Kirby-Gallagher LM Garcia-Garcia C Giles RH Goodman MC Heller K Heppelman S Hill N Hoftiezer JH Jankowski DJ Johns K Joyce T Kafka T Litchfield PJ Lopez FV Lowe M Mann WA Marshak ML May EN McMaster L Milburn RH Miller W Napier A Oliver WP Pearce GF Perkins DH Peterson EA Price LE Roback D Rosen DB 《Physical review D: Particles and fields》1990,42(9):2967-2973