全文获取类型
收费全文 | 31161篇 |
免费 | 5386篇 |
国内免费 | 7900篇 |
专业分类
化学 | 23632篇 |
晶体学 | 857篇 |
力学 | 1922篇 |
综合类 | 1023篇 |
数学 | 4255篇 |
物理学 | 12758篇 |
出版年
2024年 | 65篇 |
2023年 | 276篇 |
2022年 | 854篇 |
2021年 | 869篇 |
2020年 | 934篇 |
2019年 | 1001篇 |
2018年 | 902篇 |
2017年 | 1035篇 |
2016年 | 1130篇 |
2015年 | 1474篇 |
2014年 | 1717篇 |
2013年 | 2347篇 |
2012年 | 2442篇 |
2011年 | 2590篇 |
2010年 | 2361篇 |
2009年 | 2418篇 |
2008年 | 2754篇 |
2007年 | 2507篇 |
2006年 | 2374篇 |
2005年 | 2131篇 |
2004年 | 1739篇 |
2003年 | 1410篇 |
2002年 | 1501篇 |
2001年 | 1310篇 |
2000年 | 1291篇 |
1999年 | 880篇 |
1998年 | 494篇 |
1997年 | 467篇 |
1996年 | 385篇 |
1995年 | 375篇 |
1994年 | 320篇 |
1993年 | 323篇 |
1992年 | 302篇 |
1991年 | 216篇 |
1990年 | 190篇 |
1989年 | 175篇 |
1988年 | 144篇 |
1987年 | 139篇 |
1986年 | 101篇 |
1985年 | 74篇 |
1984年 | 87篇 |
1983年 | 77篇 |
1982年 | 50篇 |
1981年 | 50篇 |
1980年 | 54篇 |
1979年 | 24篇 |
1978年 | 17篇 |
1977年 | 15篇 |
1975年 | 9篇 |
1959年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
82.
Introduction In the previous studies on the oxidation reaction,peroxydisulfate was widely used as an oxidizingagent.1-5 One of the advantages of this oxidant lies in itsstability in a wide range of pH values. The reaction be-tween Fe(CN)5L3- (L=N-aromatic heterocyclic li-gands) and S2O8 2- has been proved to proceed throughan outer-sphere electron transfer mechanism.5 For a re-action [(Eq. (1)] to be under an outer-sphere mechanismthe steps involved are the formation of a reactant … 相似文献
83.
The polyacrylic acid functionalized polystyrene nanospheres were synthesized and self-assembled into irregular, densely packed monolayers in non-aqueous media. The polymer nanoparticles were chemically adhered to substrates. The morphologies of the resulting films were investigated. The impact of the volume fraction of alcohol in the mixed solvents on the particle adsorption and fabrication of nanosphere assembled films was examined. 相似文献
84.
Gui Hong YAN Da XING* Shi Ci TAN Institute of Laser Life Science South China Normal University Guangzhou 《中国化学快报》2004,15(1):101-104
Electrochemiluminescence (ECL), like other chemiluminescence technique, offers high signal-to-noise ratio. Furthermore, it has the advantage over other chemiluminescence techniques of being initiated by a voltage potential. Thus, it provides a better-controlled luminescence. This technique has been used in measuring many kinds of organic and inorganic matters, and analyzing many kinds of antigen, antibody and hapten, such as carcinoembryonic antigen and alpha-fetoprotein, etc1-6. The ele… 相似文献
85.
Direct Observation of Non-covalent Complexes for Phosphorylated Flavonoid-protein Interaction by ESI
XiaoLanCHEN TingZHANG HongXiaLIU LingBoQU YouZhuYU YuFenZHAO 《中国化学快报》2004,15(3):343-346
Diethyl flavon-7-yl phosphate was synthesized by modified Atheron-Todd reaction. The result of ESI shows that the phosphated flavonoids possess stronger binding affinities toward proteins such as myoglobin, insulin and lysozyme and are easier to form the non-covalent complexes with them. 相似文献
86.
FengSHI HongYangLI XiaoJunPENG RongZHANG XiaoQiangCHEN JiangLiFAN LiChengSUN 《中国化学快报》2004,15(12):1407-1410
As photosensitizer for solar cell, a new ruthenium (Ⅱ) complex with four ester groups had been synthesized, in which a phenol substituted by {[(2-hydroxy-5-tert-butylbenzyl)(pyridyl-2-methyl)amino]methyl} is covalently linked to ruthenium (Ⅱ) tris-bipyridine. The structures of the new compounds were confirmed by NMR and ESI-MS spectra. The electrochemical and photochemical properties were also studied. 相似文献
87.
The first hyperpolarizabilities of a series of novel azulenic-barbituric acid chromophores have been studied by using 12 excitation wavelengths, ranging from 900 to 1907 nm. The dispersion relation of the first hyperpolarizabilities of chromophores holds the same tendency as the experimental results. In addition, the static first hyperpolarizability β0 of molecules was calculated by means of the Sum-Over-States (SOS) expression and the two-level formula respectively. The results show that these molecules possess large static first hyperpolarizabilities and the, β0 value increases as the donor or acceptor strength enhances; the distorted degree of molecules has also an important influence on the β0 value. 相似文献
88.
Zhong Hong YAN Chun Hao YANG Xi Han WU Yu Yuan XIEDivision of Chemistry Shanghai Second Medical University Shanghai Sate Key Laboratory of Drug Research Shanghai Institute of Materia Medica Shanghai Institutesfor Biological Sciences Shanghai 《中国化学快报》2004,(4)
The first and facile synthesis of (±)syringaresinol was described. 相似文献
89.
Ming Zhao WANG Guan Liang CAI Ling XIA Jun Jian YAO Hong Yan CHEN Zhao Xing MENG Bo Li LIUDepartment of Chemistry Beijing Normal University Beijing Chemical Defense Institute PLA Beijing 《中国化学快报》2004,15(4):495-497
The crystal structures of two potential tumor imaging agents and therapeutic agents -copper(Ⅱ) complexes with salicylidene-tyrosinato Schiff base and nitrogen-donor chelating Lewis base, [Cu(sal-tyr)(bipy)] 1 and [Cu(sal-tyr)(phen)]2CH3OH 2 are presented. Our work is helpful to get deep understanding of novel 64Cu tumor imaging agents and therapeutic agents. 相似文献
90.
Yoshimi Egawa Mariko Hagita Ken-ichi Kawarabayashi Hong Wang 《Discrete Mathematics》2003,270(1-3):115-125
Let d, k and n be three integers with k3, d4k−1 and n3k. We show that if d(x)+d(y)d for each pair of nonadjacent vertices x and y of a graph G of order n, then G contains k vertex-disjoint cycles converting at least min{d,n} vertices of G. 相似文献