全文获取类型
收费全文 | 10215篇 |
免费 | 202篇 |
国内免费 | 74篇 |
专业分类
化学 | 414篇 |
晶体学 | 11篇 |
力学 | 66篇 |
综合类 | 6篇 |
数学 | 9437篇 |
物理学 | 557篇 |
出版年
2023年 | 19篇 |
2022年 | 26篇 |
2021年 | 26篇 |
2020年 | 54篇 |
2019年 | 279篇 |
2018年 | 284篇 |
2017年 | 167篇 |
2016年 | 136篇 |
2015年 | 121篇 |
2014年 | 249篇 |
2013年 | 611篇 |
2012年 | 274篇 |
2011年 | 595篇 |
2010年 | 496篇 |
2009年 | 676篇 |
2008年 | 788篇 |
2007年 | 811篇 |
2006年 | 607篇 |
2005年 | 380篇 |
2004年 | 353篇 |
2003年 | 316篇 |
2002年 | 246篇 |
2001年 | 192篇 |
2000年 | 194篇 |
1999年 | 247篇 |
1998年 | 227篇 |
1997年 | 163篇 |
1996年 | 242篇 |
1995年 | 214篇 |
1994年 | 202篇 |
1993年 | 171篇 |
1992年 | 120篇 |
1991年 | 87篇 |
1990年 | 87篇 |
1989年 | 88篇 |
1988年 | 59篇 |
1987年 | 60篇 |
1986年 | 65篇 |
1985年 | 88篇 |
1984年 | 61篇 |
1983年 | 51篇 |
1982年 | 63篇 |
1981年 | 60篇 |
1980年 | 54篇 |
1979年 | 39篇 |
1978年 | 44篇 |
1977年 | 35篇 |
1976年 | 38篇 |
1975年 | 10篇 |
1974年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
O. Y. Loukianov 《Potential Analysis》1992,1(4):337-341
The paper is related to the question of uniqueness in the inverse logarithmic potential problem. This question is to find the conditions on which two domains D
1 and D
2 producing the same external potential must coincide. Assuming the general hypothesis of regularity and an additional condition of connectivity of (D1D2)c, we prove a theorem of uniqueness in the case when one of the domains is a lemniscate. The main tool is one lemma for Cauchy's potential due to M. Sakai. We give a simple proof of its extension to Newtonian potential. 相似文献
72.
Š. Porubský 《Periodica Mathematica Hungarica》1982,13(1):9-14
A necessary and sufficient condition for the group of isomorphisms involved in a factorization of a complete graph into isomorphic factors is established. 相似文献
73.
Kuo-yuan Hung Renata Kowalczyk Ami Desai Margaret A. Brimble John F. Marshall Paul W. R. Harris 《Molecules (Basel, Switzerland)》2022,27(14)
A20FMDV2 is a 20-mer peptide that exhibits high selectivity and affinity for the tumour-related αvβ6 integrin that can compete with extracellular ligands for the crucial RGD binding site, playing a role as a promising αvβ6-specific inhibitor for anti-cancer therapies. Unfortunately, the clinical value of A20FMDV2 is limited by its poor half-life in blood caused by rapid renal excretion and its reported high susceptibility to serum proteases. The incorporation of poly (ethylene glycol) chains, coined PEGylation, is a well-established approach to improve the pharmacokinetic properties of drug molecules. Here, we report a systematic study on the incorporation of a varying number of ethylene glycol units (1–20) into the A20FMDV2 peptide to establish the effects of PEGylation size on the peptide stability in both rat serum and human plasma. In addition, the effect of acetyl and propionyl PEGylation handles on peptide stability is also described. Selected peptide analogues were assessed for integrin-αvβ6-targeted binding, showing good specificity and activity in vitro. Stability studies in rat serum established that all of the PEGylated peptides displayed good stability, and an A20FMDV2 peptide containing twenty ethylene glycol units (PEG20) was the most stable. Surprisingly, the stability testing in human plasma identified shorter PEGs (PEG2 and PEG5) as more resistant to degradation than longer PEGs, a trend which was also observed with affinity binding to integrin αvβ6. 相似文献
74.
Deformed Hartree-Fock calculations are performed for some light nuclei in a large configuration space consisting of first
four major shells. The interaction employed is the modified Skyrme interaction in which the deformed density is replaced by
the band averaged scalar density that makes the Hamiltonian rotationally invariant rendering the spectroscopic calculations
feasible. It is shown that the introduction of density dependence spreads out the energy spectra and that the Skyrme variant
SIV which has a weak density dependence gives best overall agreement for energy spectra and the available data for the electromagnetic
properties of the nuclei studied. It is found that the maximum contribution to the energy of any state in the low lying spectrum
comes from thes-state attractive ands-state repulsive parts of the Skyrme interaction. It is also shown that when two-body density dependent version of Skyrme
interaction is used, the Koopmans theorem no longer holds. 相似文献
75.
76.
A bicyclo[2.2.2]octane C/D ring system,with a lactonic ring at C-8 and C-9,of the atisine-type C20-diterpenoid alkaloids,was successfully synthesized,using an oxidative dearomatization/intramolecular Diels-Alder reaction. 相似文献
77.
78.
79.
80.