全文获取类型
收费全文 | 6016篇 |
免费 | 438篇 |
国内免费 | 15篇 |
专业分类
化学 | 4818篇 |
晶体学 | 36篇 |
力学 | 69篇 |
数学 | 697篇 |
物理学 | 849篇 |
出版年
2024年 | 10篇 |
2023年 | 58篇 |
2022年 | 83篇 |
2021年 | 107篇 |
2020年 | 197篇 |
2019年 | 187篇 |
2018年 | 77篇 |
2017年 | 98篇 |
2016年 | 266篇 |
2015年 | 251篇 |
2014年 | 300篇 |
2013年 | 326篇 |
2012年 | 466篇 |
2011年 | 498篇 |
2010年 | 289篇 |
2009年 | 240篇 |
2008年 | 373篇 |
2007年 | 352篇 |
2006年 | 319篇 |
2005年 | 258篇 |
2004年 | 243篇 |
2003年 | 199篇 |
2002年 | 193篇 |
2001年 | 107篇 |
2000年 | 86篇 |
1999年 | 75篇 |
1998年 | 70篇 |
1997年 | 79篇 |
1996年 | 66篇 |
1995年 | 73篇 |
1994年 | 87篇 |
1993年 | 51篇 |
1992年 | 48篇 |
1991年 | 43篇 |
1990年 | 33篇 |
1989年 | 45篇 |
1988年 | 30篇 |
1987年 | 24篇 |
1986年 | 19篇 |
1985年 | 11篇 |
1984年 | 13篇 |
1983年 | 8篇 |
1982年 | 10篇 |
1981年 | 15篇 |
1980年 | 19篇 |
1979年 | 13篇 |
1978年 | 16篇 |
1977年 | 14篇 |
1976年 | 8篇 |
1975年 | 3篇 |
排序方式: 共有6469条查询结果,搜索用时 203 毫秒
981.
Matthias Kurzke 《Journal of Functional Analysis》2008,255(3):535-588
We consider the Gamma limit of the Abelian Chern-Simons-Higgs energy
982.
We characterize the domain of the realizations of a linear parabolicoperator defined in L2 spaces with respect to a suitable measurethat is invariant for the associated evolution semigroup. Asa byproduct, we obtain optimal L2 regularity results for evolutionequations with time-dependant Ornstein–Uhlenbeck operators. 相似文献
983.
Cotí KK Wang Y Lin WY Chen CC Tak For Yu Z Liu K Shen CK Selke M Yeh A Lu W Tseng HR 《Chemical communications (Cambridge, England)》2008,(29):3426-3428
A new type of dynamic micromixer combining the concepts of parallel multi-lamination and hydrodynamic focusing was developed for arbitrary control of disguised chemical selectivity. 相似文献
984.
985.
The geometry of Re2Cl82− has been optimized for the eclipsed (D
4h
) equilibrium conformation and for the staggered (D
4d
) conformation at BP86/TZ2P. The nature of the Re–Re bond which has a formal bond order four has been studied with an energy
decomposition analysis (EDA). The EDA investigation indicates that the contribution of the b
2 (δ
xy
) orbitals to the Re–Re bond in the ground state is negligibly small. The vertical excitation of one and two electrons from the bonding δ orbital into the antibonding δ* orbitals yielding the singly and doubly excited states and gives a destabilization of 17.5 and 36.1 kcal/mol, respectively, which is nearly the same as the total excitation energies.
The preference for the D
4h
geometry with eclipsing Re–Cl bonds is explained in terms of hyperconjugation rather than δ bonding. This is supported by the calculation of the triply bonded Re2Cl8 which also has an eclipsed energy minimum structure. The calculations also suggest that the Re–Re triple bond in Re2Cl8 is stronger than the Re–Re quadruple bond in Re2Cl82−. A negligible contribution of the δ orbital to the metal–metal bond strength is also calculated for Os2Cl8 which is isoelectronic with Re2Cl82−.
Contribution of the Mark S. Gordon 65th Birthday Festschrift Issue.
Theoretical Studies of Inorganic Compounds. 38. Part 37 (2006) Bessac F, Frenking G, Inorg Chem 45:6956. 相似文献
986.
987.
988.
989.
990.
Matthias Busker Michael Nispel Dr. Thomas Häber Dr. Karl Kleinermanns Prof. Dr. Mihajlo Etinski Timo Fleig Dr. 《Chemphyschem》2008,9(11):1570-1577
Electronic and vibrational gas phase spectra of 1‐methylthymine (1MT) and 1‐methyluracil (1MU) and their clusters with water are presented. Mass selective IR/UV double resonance spectra confirm the formation of pyrimidine‐water clusters and are compared to calculated vibrational spectra obtained from ab initio calculations. In contrast to Y. He, C. Wu, W. Kong; J. Phys. Chem. A, 2004 , 108, 94 we are able to detect 1MT/1MU and their water clusters via resonant two‐photon delayed ionization under careful control of the applied water‐vapor pressure. The long‐living dark electronic state of 1MT and 1MU detected by delayed ionization, survives hydration and the photostability of 1MT/1MU cannot be attributed solely to hydration. Oxygen coexpansions and crossed‐beam experiments indicate that the triplet state population is probably small compared to the 1nπ* and/or hot electronic ground state population. Ab initio theory shows that solvation of 1MT by water does not lead to a substantial modification of the electronic relaxation and quenching of the 1nπ* state. Relaxation pathways via 1ππ*1–nπ*1 and 1ππ *–S0 conical intersections and barriers have been identified, but are not significantly altered by hydration. 相似文献