全文获取类型
收费全文 | 10434篇 |
免费 | 329篇 |
国内免费 | 2篇 |
专业分类
化学 | 5428篇 |
晶体学 | 132篇 |
力学 | 186篇 |
数学 | 2069篇 |
物理学 | 2950篇 |
出版年
2021年 | 148篇 |
2020年 | 140篇 |
2019年 | 128篇 |
2018年 | 199篇 |
2017年 | 222篇 |
2016年 | 467篇 |
2015年 | 308篇 |
2014年 | 353篇 |
2013年 | 801篇 |
2012年 | 485篇 |
2011年 | 621篇 |
2010年 | 400篇 |
2009年 | 342篇 |
2008年 | 319篇 |
2007年 | 273篇 |
2006年 | 203篇 |
2005年 | 161篇 |
2004年 | 156篇 |
2003年 | 157篇 |
2002年 | 167篇 |
2001年 | 137篇 |
2000年 | 128篇 |
1999年 | 138篇 |
1998年 | 129篇 |
1997年 | 126篇 |
1996年 | 134篇 |
1995年 | 118篇 |
1994年 | 112篇 |
1993年 | 123篇 |
1992年 | 116篇 |
1991年 | 104篇 |
1990年 | 105篇 |
1989年 | 101篇 |
1988年 | 100篇 |
1987年 | 122篇 |
1986年 | 88篇 |
1985年 | 128篇 |
1984年 | 129篇 |
1983年 | 122篇 |
1982年 | 118篇 |
1981年 | 114篇 |
1980年 | 116篇 |
1979年 | 125篇 |
1978年 | 119篇 |
1977年 | 113篇 |
1976年 | 112篇 |
1975年 | 98篇 |
1974年 | 103篇 |
1973年 | 102篇 |
1966年 | 82篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
991.
992.
993.
994.
995.
In this paper we prove a uniform and scale invariant boundary Harnack principle at infinity for a large class of purely discontinuous Feller processes in metric measurespaces. 相似文献
996.
Jan Turek Zdeňka Růžičková Eva Tloušťová Helena Mertlíková‐Kaiserová Jana Günterová Lubomír Rulíšek Aleš Růžička 《应用有机金属化学》2016,30(5):318-322
Two gold(I) complexes of the (NHC)AuX type bearing a triazole‐based N‐heterocyclic carbene (NHC) ligand (1‐tert‐butyl‐4‐(4‐methylphenyl)‐3‐phenyl‐1H‐1,2,4‐triazol‐4‐ium‐5‐ylidene) and various halide ligands (X = Br, I) were synthesized and characterized in solution using NMR spectroscopy as well as in the solid state using X‐ray diffraction techniques. The cytotoxic properties of both compounds and the precursor, (NHC)AuCl, were screened against a panel of human tumour cell lines including liver cancer (HepG2), cervical cancer (HeLa S3) and leukaemia (CCRF‐CEM, HL‐60) and compared to cisplatin and auranofin. It was found that the activities of the chloro and bromo derivatives were generally superior to that of cisplatin and slightly less effective compared to auranofin, except for HepG2 cells where auranofin was not as effective. In addition, the ability to induce membrane phosphatidyl serine externalization as a hallmark of apoptosis in CCRF‐CEM leukaemic cells was investigated. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
997.
998.
Tomáš Řezníček Libor Dostál Aleš Růžička Jiří Kulhánek Filip Bureš Roman Jambor 《应用有机金属化学》2011,25(3):173-179
The phosphines L1PPh2 (1) and L2PPh2 (2) containing different Y,C,Y‐chelating ligands, L1 = 2,6‐(tBuOCH2)2C6H3? and L2 = 2,6‐(Me2NCH2)2C6H3?, were treated with PdCl2 and di‐µ‐chloro‐bis[2‐[(N,N‐dimethylamino)methyl]phenyl‐C,N]‐dipalladium(II) and yielded complexes trans‐{[2,6‐(tBuOCH2)2C6H3]PPh2}2PdCl2 (3), {[2,6‐(Me2NCH2)2C6H3]PPh2} PdCl2 (4), {[2,6‐(tBuOCH2)2C6H3]PPh2}Pd(Cl)[2‐(Me2NCH2)C6H4] (5) and {[2,6‐(Me2NCH2)2C6H3]PPh2}Pd(Cl)[2‐(Me2NCH2)C6H4] (6) as the result of different ability of starting phosphines 1 and 2 to complex PdCl2. Compounds 3–6 were characterized by 1H, 13C, 31P NMR spectroscopy and ESI‐MS. The molecular structures of 3,4 and 6 were also determined by X‐ray diffraction analysis. The catalytic activity of complexes 3–6 was evaluated in the Suzuki‐Miyaura cross‐coupling reaction. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
999.
Dijana Ilišević 《Acta Mathematica Hungarica》2011,132(4):387-400
The problem of representability of quadratic functionals (acting on modules over unital complex ∗-algebras), by sesquilinear
forms, is generalized by weakening the homogeneity equation. The corresponding representation theorem can be considered as
a generalization of (the original form of) the classical Jordan–von Neumann characterization of complex inner product spaces. 相似文献
1000.
Marija Mirković Drina Janković Sanja Vranješ‐Đurić Magdalena Radović Dragana Stanković Dušan Mijin Nadežda Nikolić 《应用有机金属化学》2012,26(7):347-355
Two novel diamine dioxime ligands, 4,7‐diaza‐3,8‐diethyldecane‐2,9‐dione bis oxime (3) and 4,9‐diaza‐3,10‐diethyldodecane‐2,11‐dione bis oxime (5), were synthesized in order to develop new brain perfusion imaging agents, based on 99mTc(V)‐complexes. The synthesis involved condensation of 2‐hydroxyimino‐3‐pentanone with appropriate diamine in protic solvent which afforded the bis imine adducts. Subsequent reduction of imine functional groups yielded a diastereoisomeric mixture of 3 and 5. UV–visible, IR, 1H NMR, 13C NMR and elemental analysis were used to characterize the structures of the synthesized compounds. 99mTc‐complexes of both diamine dioximes were prepared and radiolabeling conditions optimized to give the maximum yield. Physicochemical parameters of the labeled complexes as well as and their biodistribution in rats were investigated. Both compounds (3 and 5) formed 99mTc‐complexes with a net charge of zero, determined by electrophoresis. The resultant lipophilic 99mTc‐complexes of 3 and 5 were readily formed at pH ~9.0 within 10 min at room temperature with yields of 90% and 95%, respectively. The 99mTc‐3 complex was found to be stable within 1 h, while 99mTc‐5 was stable for a few hours. A significant brain uptake of 99mTc‐3 (2.1% injected dose) and 99mTc‐5 (1.8% injected dose) complexes, 2 min after injection, is in accordance with their lipophilicity. The present study suggests that both ligands are promising candidates as new 99mTc‐based brain‐imaging agents. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献