全文获取类型
收费全文 | 426897篇 |
免费 | 21636篇 |
国内免费 | 881篇 |
专业分类
化学 | 237513篇 |
晶体学 | 5195篇 |
力学 | 21669篇 |
综合类 | 16篇 |
数学 | 64559篇 |
物理学 | 120462篇 |
出版年
2023年 | 4995篇 |
2021年 | 6078篇 |
2020年 | 8747篇 |
2019年 | 7038篇 |
2018年 | 10337篇 |
2017年 | 9055篇 |
2016年 | 15550篇 |
2015年 | 10804篇 |
2014年 | 13700篇 |
2013年 | 20940篇 |
2012年 | 18682篇 |
2011年 | 18122篇 |
2010年 | 16552篇 |
2009年 | 16142篇 |
2008年 | 15811篇 |
2007年 | 15283篇 |
2006年 | 13414篇 |
2005年 | 15389篇 |
2004年 | 14282篇 |
2003年 | 11821篇 |
2002年 | 10297篇 |
2001年 | 9003篇 |
2000年 | 7134篇 |
1999年 | 5455篇 |
1998年 | 5112篇 |
1997年 | 5038篇 |
1996年 | 4697篇 |
1995年 | 4267篇 |
1994年 | 4316篇 |
1993年 | 4444篇 |
1992年 | 4397篇 |
1991年 | 4630篇 |
1990年 | 4582篇 |
1989年 | 4527篇 |
1988年 | 4316篇 |
1987年 | 4296篇 |
1986年 | 3945篇 |
1985年 | 4762篇 |
1984年 | 4994篇 |
1983年 | 4310篇 |
1982年 | 4574篇 |
1981年 | 4253篇 |
1980年 | 4022篇 |
1979年 | 4438篇 |
1978年 | 4564篇 |
1977年 | 4799篇 |
1976年 | 4877篇 |
1975年 | 4619篇 |
1974年 | 4481篇 |
1973年 | 4476篇 |
排序方式: 共有10000条查询结果,搜索用时 515 毫秒
181.
Journal of Analytical Chemistry - Studies on the separation of the Se and Te trace components from Co, Ni, Cu, Fe, Cr, Mo, and W macrocomponents for their determination by inductively coupled... 相似文献
182.
V. V. Sagaradze N. V. Kataeva V. A. Zavalishin K. A. Kozlov V. V. Makarov A. R. Kuznetsov 《哲学杂志》2020,100(14):1868-1879
ABSTRACT The authors present the results of an investigation in Fe–Ni-Cr austenitic alloys of the low-temperature deformation-induced segregations of nickel that form in the micro regions being (i) located close to grain- and subgrain boundaries and (ii) characteristic of the concentration and magnetic inhomogeneities indicated by the appearance of a dark diffraction contrast at the electron diffraction patterns taken from these regions typical (at the same time) of an enhanced value of Curie temperature. The observed effects were connected with the micro distortions caused by the local change of lattice parameter because of an increase in nickel concentration, as well as in the result of a magnetostriction dilatation. Using methods of the X-ray energy dispersive spectroscopy (XEDS) and atomic-probe body-section radiography (tomography – APT) has made it possible to determine the borders of those regions of austenite that were characteristic of an enhanced concentration of nickel in the fields of the localisation of a deformation-induced segregation of nickel in the vicinity of grain (subgrain) boundaries of austenitic alloys of the types Fe–13Cr–30Ni and Fe–37Ni–3Ti. 相似文献
183.
184.
185.
Tuning the Basicity of Cyano‐Containing Ionic Liquids to Improve SO2 Capture through Cyano–Sulfur Interactions
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Guokai Cui Fengtao Zhang Xiuyuan Zhou Prof. Haoran Li Prof. Jianji Wang Prof. Congmin Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5632-5639
A new approach has been developed to improve SO2 sorption by cyano‐containing ionic liquids (ILs) through tuning the basicity of ILs and cyano–sulfur interaction. Several kinds of cyano‐containing ILs with different basicity were designed, prepared, and used for SO2 capture. The interaction between these cyano‐containing ILs and SO2 was investigated by FTIR and NMR methods. Spectroscopic investigations and quantum chemical calculations showed that dramatic effects on SO2 capacity originate from the basicity of the ILs and enhanced cyano–sulfur interaction. Furthermore, the captured SO2 was easy to release by heating or bubbling N2 through the ILs. This efficient and reversible process, achieved by tuning the basicity of ILs, is an excellent alternative to current technologies for SO2 capture. 相似文献
186.
I. F. Golovnev E. I. Golovneva L. A. Merzhievsky V. M. Fomin V. E. Panin 《Physical Mesomechanics》2015,18(3):179-186
Molecular dynamics simulation was performed to study the formation of cluster structure, interfaces, and surfaces with different curvature radii in a perfect nanocrystal passed through by a nonlinear wave. It is shown that this process is a type of nanostructure self-organization in response to an external energy flux with subsequent development of a strong rotational field. 相似文献
187.
188.
Marius Lupu Adnana Zaulet Prof. Dr. Francesc Teixidor Prof. Dr. Eliseo Ruiz Prof. Dr. Clara Viñas 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(18):6888-6897
The metallacarborane [3,3′‐Co(1,2‐closo‐C2B9H11)2]? has been synthesized. This species allows the formation of redox couples in which both partners are negatively charged. The E1/2 potential can be tuned by adjusting the nature and number of substituents on B and C. The octaiodinated species [3,3′‐Co(1,2‐closo‐C2B9H7I4)2]? is the most favorable, as it is isolatable and stable in air. A DFT study on stability and redox potentials of complexes has been performed. 相似文献
189.
190.
Hui Li Jian Liu Juan Zhao Huiting He Dr. Dabo Jiang Prof. Steven Robert Kirk Prof. Qiong Xu Dr. Xianxiang Liu Prof. Dulin Yin 《ChemistryOpen》2021,10(4):477-485
A series of tetraimidazolium salts with different anions was prepared and applied in the isomerization of β-pinene oxide. After examining the activity of different catalysts, a remarkable enhancement of the selectivity of perillyl alcohol (47 %) was obtained over [PEimi][HNO3]4 under mild reaction conditions and using DMSO as the solvent. Furthermore, noncovalent interactions between solvent molecules and the catalyst were found by FT-IR spectroscopy and confirmed by computational chemistry. The homogeneous catalyst showed excellent stability and was reused up to six times without significant loss. 相似文献