全文获取类型
收费全文 | 493202篇 |
免费 | 4387篇 |
国内免费 | 1488篇 |
专业分类
化学 | 255815篇 |
晶体学 | 7769篇 |
力学 | 22311篇 |
综合类 | 11篇 |
数学 | 59081篇 |
物理学 | 154090篇 |
出版年
2021年 | 4297篇 |
2020年 | 4654篇 |
2019年 | 5223篇 |
2018年 | 7197篇 |
2017年 | 7350篇 |
2016年 | 10130篇 |
2015年 | 5834篇 |
2014年 | 9660篇 |
2013年 | 22800篇 |
2012年 | 17319篇 |
2011年 | 20804篇 |
2010年 | 15282篇 |
2009年 | 15139篇 |
2008年 | 19122篇 |
2007年 | 19182篇 |
2006年 | 17734篇 |
2005年 | 15673篇 |
2004年 | 14359篇 |
2003年 | 12842篇 |
2002年 | 12746篇 |
2001年 | 14571篇 |
2000年 | 11048篇 |
1999年 | 8563篇 |
1998年 | 7212篇 |
1997年 | 7111篇 |
1996年 | 6650篇 |
1995年 | 5679篇 |
1994年 | 5705篇 |
1993年 | 5633篇 |
1992年 | 6090篇 |
1991年 | 6364篇 |
1990年 | 6049篇 |
1989年 | 5946篇 |
1988年 | 5707篇 |
1987年 | 5773篇 |
1986年 | 5515篇 |
1985年 | 7073篇 |
1984年 | 7230篇 |
1983年 | 5968篇 |
1982年 | 6266篇 |
1981年 | 5925篇 |
1980年 | 5702篇 |
1979年 | 6156篇 |
1978年 | 6263篇 |
1977年 | 6254篇 |
1976年 | 6227篇 |
1975年 | 5875篇 |
1974年 | 5801篇 |
1973年 | 5999篇 |
1972年 | 4176篇 |
排序方式: 共有10000条查询结果,搜索用时 55 毫秒
161.
Krylov A. S. Tolstyakov V. V. Gurzhiy V. V. Dogadina A. V. 《Russian Journal of General Chemistry》2021,91(1):72-76
Russian Journal of General Chemistry - A series of new 6-phosphonylated 1H-imidazo[2,1-c][1,2,4]triazoles was synthesized by the reaction of diethyl chloroethynylphosphonate with 2-substituted... 相似文献
162.
Nikiforova E. A. Makhmudov R. R. Rudin A. A. Dmitriev M. V. Baibarodskikh D. V. Kirillov N. F. Zverev D. P. Romanov A M. 《Russian Journal of General Chemistry》2021,91(1):64-71
Russian Journal of General Chemistry - Depending on the ring size in the Reformatsky reagent and the nature of substituents in arylmethylidene fragment, the reactions of Reformatsky reagents... 相似文献
163.
Russian Journal of Coordination Chemistry - Two 2D cobalt complexes, namely {[(Bipmo)2Co2(Ipa)2](DMF)]·2.25H2O}n (I), {[(Bipmo)-Co(Ipa)]·2H2O}n (II), have been constructed solvothermally... 相似文献
164.
Zaitsev K. V. Oprunenko A. Yu. Gloriozov I. P. Nechaev M. S. Oprunenko Yu. F. Kuznetsov A. E. 《Russian Journal of General Chemistry》2021,91(5):828-834
Russian Journal of General Chemistry - Structures of exo- and endo-complexes of fullerene C60 with zero-valent Fe0, in which the metal is localized inside and outside fullerene molecule,... 相似文献
165.
Russian Journal of Organic Chemistry - 3-tert-Butyl-8-nitro-7-R-pyrazolo[5,1-c][1,2,4]triazin-4(6H)-ones (R = H, Cl, Br, NO2, N3) were prepared by nitration with HNO3/H2SO4 of the corresponding... 相似文献
166.
Russian Journal of Organic Chemistry - A simple and efficient protocol has been described for the synthesis of [1,2,4]triazolo[4,3-a]pyridines and 3,5-disubstituted-1,2,4-oxadiazoles by... 相似文献
167.
Vedenyapina M. D. Kuznetsov V. V. Kulaishin S. A. Makhova N. N. Kazakova M. M. 《Russian Journal of Organic Chemistry》2021,57(9):1417-1422
Russian Journal of Organic Chemistry - The kinetics and mechanism of corrosion of gold anode in a weakly basic aqueous solution of N,N-dimethylpropane-1,3-diamine have been studied by cyclic... 相似文献
168.
N.?V.?Yashin E.?B.?AverinaEmail author D.?A.?Vasilenko Yu.?K.?Grishin D.?I.?Osolodkin V.?A.?Palyulin T.?S.?Kuznetsova N.?S.?Zefirov 《Russian Chemical Bulletin》2017,66(8):1483-1490
3-Methylenecyclobutanecarboxylic acid and its methyl ester were used as the starting compounds for the synthesis of new spiro[2.3]hexane amino acids, the conformationally rigid analogs of γ-aminobutyric acid, namely, 5-aminospiro[2.3]hexanecarboxylic and 5-amino-spiro[2.3]hexanephosphonic acids, promising modulators of GABAergic cascades in the human central nervous system. The methods developed for the synthesis of the target amino acids are based on the reactions of catalytic [1+2] cycloaddition of diazoacetic and diazophosphonic esters to 3-substituted methylenecyclobutanes, as well as on a modified Curtius reaction for the transformation of a carboxy group to the amine one. 相似文献
169.
S.?N.?Melnikov K.?A.?Lyssenko I.?V.?AnanyevEmail author I.?L.?Eremenko 《Russian Chemical Bulletin》2017,66(9):1550-1556
The results of geometric analysis of 588 crystal structures of square-planar nickel complexes containing short intermolecular Ni…X contacts (X is a non-metal atom) are reported. The frequency of occurrence of Ni…X interactions of a particular type was evaluated depending on the nature of the X atom and geometric characteristics. The promolecular functions RDG and sign(λ2)?ρ(r) were used to analyze the character of Ni…X interactions in attractive/repulsive terms. The relative strength of these interactions was determined as the function of the nature of the X atom and the direction of charge transfer. 相似文献
170.
A.?P.?Orlov T.?P.?Trofimova E.?Yu.?Osipova A.?N.?Proshin M.?A.?OrlovaEmail author 《Russian Chemical Bulletin》2017,66(10):1860-1866
A platform containing three anticancer components is proposed. The components are a radioactive 69mZn isotope and zinc complexes, where both zinc and ligand exhibit anticancer properties. Two zinc-containing complexes, namely (2-AP)2ZnCl2 and (2-AP)2Zn(Sal)2 (AP is 2-aminopyrimidine, Sal is salicylate) were synthesized and characterized. Their cytotoxicity with respect to some leukemia cell lines is demonstrated. Their stability in physiological solution and percentage of apoptosis (by flow cytometry) are investigated. Stable complexes of compounds with the isotope 69mZn were characterized by TLC and autoradiography. 相似文献