全文获取类型
收费全文 | 233118篇 |
免费 | 3603篇 |
国内免费 | 1456篇 |
专业分类
化学 | 131052篇 |
晶体学 | 2799篇 |
力学 | 9274篇 |
综合类 | 61篇 |
数学 | 27037篇 |
物理学 | 67954篇 |
出版年
2020年 | 2118篇 |
2019年 | 2241篇 |
2018年 | 2700篇 |
2017年 | 2731篇 |
2016年 | 4192篇 |
2015年 | 2860篇 |
2014年 | 4049篇 |
2013年 | 9655篇 |
2012年 | 8666篇 |
2011年 | 10589篇 |
2010年 | 7256篇 |
2009年 | 6989篇 |
2008年 | 9680篇 |
2007年 | 9753篇 |
2006年 | 9228篇 |
2005年 | 8433篇 |
2004年 | 7510篇 |
2003年 | 6484篇 |
2002年 | 6435篇 |
2001年 | 6859篇 |
2000年 | 5197篇 |
1999年 | 3813篇 |
1998年 | 3151篇 |
1997年 | 3084篇 |
1996年 | 2919篇 |
1995年 | 2661篇 |
1994年 | 2764篇 |
1993年 | 2636篇 |
1992年 | 2843篇 |
1991年 | 2922篇 |
1990年 | 2701篇 |
1989年 | 2613篇 |
1988年 | 2589篇 |
1987年 | 2517篇 |
1986年 | 2525篇 |
1985年 | 3340篇 |
1984年 | 3407篇 |
1983年 | 2818篇 |
1982年 | 3109篇 |
1981年 | 2874篇 |
1980年 | 2666篇 |
1979年 | 2832篇 |
1978年 | 3080篇 |
1977年 | 3097篇 |
1976年 | 3096篇 |
1975年 | 2844篇 |
1974年 | 2945篇 |
1973年 | 3000篇 |
1972年 | 2321篇 |
1971年 | 1847篇 |
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
1.
Kinetics and Catalysis - The catalytic properties of a nickel phosphide catalyst supported on silica gel in the reductive amination of carbonyl compounds were studied in a flow reactor using... 相似文献
2.
Yang T. L. Kao C. L. Kuo C. E. Yeh H. C. Li W. J. Li H. T. Chen C. Y. 《Chemistry of Natural Compounds》2022,58(5):825-827
Chemistry of Natural Compounds - A novel bibenzyl derivative, hydrangchinenin (1), was isolated from the stems of Hydrangea chinensis Maxim. (Hydrangeaceae). Its structure was determined on the... 相似文献
3.
Dr. Yolimar Gil Dr. Alejandro Castro-Alvarez Dr. Pablo Fuentealba Prof. Evgenia Spodine Dr. Daniel Aravena 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(48):e202200336
Enhancement of axial magnetic anisotropy is the central objective to push forward the performance of Single-Molecule Magnet (SMM) complexes. In the case of mononuclear lanthanide complexes, the chemical environment around the paramagnetic ion must be tuned to place strongly interacting ligands along either the axial positions or the equatorial plane, depending on the oblate or prolate preference of the selected lanthanide. One classical strategy to achieve a precise chemical environment for a metal centre is using highly structured, chelating ligands. A natural approach for axial-equatorial control is the employment of macrocycles acting in a belt conformation, providing the equatorial coordination environment, and leaving room for axial ligands. In this review, we present a survey of SMMs based on the macrocycle belt motif. Literature systems are divided in three families (crown ether, Schiff-base and metallacrown) and their general properties in terms of structural stability and SMM performance are briefly discussed. 相似文献
4.
Filatova S. M. Guseva M. K. Bodrova T. G. Parshina D. V. Budanova U. A. Sebyakin Yu. L. 《Russian Journal of General Chemistry》2022,91(1):S13-S23
Russian Journal of General Chemistry - The review article traces the main trends of the synthetic approach to the solution of the problem of overcoming the resistance of pathogenic bacterial... 相似文献
5.
Physics of Atomic Nuclei - In this paper, the analysis of the relation between the multiplication factor of neutrons of the multiplying system measured in critical experiments and the system... 相似文献
6.
Set-Valued and Variational Analysis - In a Hilbert framework ℌ, we study the convergence properties of a Newton-like inertial dynamical system governed by a general maximally monotone... 相似文献
7.
Kuklin A. I. Ivankov O. I. Rogachev A. V. Soloviov D. V. Islamov A. Kh. Skoi V. V. Kovalev Yu. S. Vlasov A. V. Ryzhykau Yu. L. Soloviev A. G. Kucerka N. Gordeliy V. I. 《Crystallography Reports》2021,66(2):231-241
Crystallography Reports - Neutron diffraction studies on the small-angle neutron spectrometer YuMO (Joint Institute for Nuclear Research, Dubna), based on the IBR-2 pulsed reactor, have been... 相似文献
8.
Kuz’mina L. G. Navasardyan M. A. Kalle P. Bezzubov S. I. 《Crystallography Reports》2021,66(3):420-423
Crystallography Reports - The crystal and molecular structures of Cl–C6H4–O–C16H33 (I) have been studied, and its differential scanning calorimetry (DSC) study is performed.... 相似文献
9.
Lebedev D. V. Egorov V. V. Shvetsov A. V. Zabrodskaya Y. A. Isaev-Ivanov V. V. Konevega A. L. 《Crystallography Reports》2021,66(2):242-253
Crystallography Reports - The review describes the application of small-angle scattering (SAS) of neutrons and complementary methods to study the structures of biomacromolecules. Here we cover SAS... 相似文献