全文获取类型
| 收费全文 | 469130篇 |
| 免费 | 4640篇 |
| 国内免费 | 1484篇 |
专业分类
| 化学 | 221110篇 |
| 晶体学 | 6363篇 |
| 力学 | 24369篇 |
| 综合类 | 7篇 |
| 数学 | 85059篇 |
| 物理学 | 138346篇 |
出版年
| 2020年 | 2017篇 |
| 2019年 | 2006篇 |
| 2018年 | 18870篇 |
| 2017年 | 19472篇 |
| 2016年 | 12506篇 |
| 2015年 | 4819篇 |
| 2014年 | 4838篇 |
| 2013年 | 14443篇 |
| 2012年 | 17675篇 |
| 2011年 | 32952篇 |
| 2010年 | 19551篇 |
| 2009年 | 19808篇 |
| 2008年 | 27348篇 |
| 2007年 | 32348篇 |
| 2006年 | 12642篇 |
| 2005年 | 19226篇 |
| 2004年 | 14754篇 |
| 2003年 | 13719篇 |
| 2002年 | 10861篇 |
| 2001年 | 10448篇 |
| 2000年 | 8211篇 |
| 1999年 | 6277篇 |
| 1998年 | 5098篇 |
| 1997年 | 4887篇 |
| 1996年 | 5062篇 |
| 1995年 | 4557篇 |
| 1994年 | 4268篇 |
| 1993年 | 4097篇 |
| 1992年 | 4547篇 |
| 1991年 | 4421篇 |
| 1990年 | 4125篇 |
| 1989年 | 3961篇 |
| 1988年 | 4263篇 |
| 1987年 | 3917篇 |
| 1986年 | 3786篇 |
| 1985年 | 5454篇 |
| 1984年 | 5540篇 |
| 1983年 | 4499篇 |
| 1982年 | 4884篇 |
| 1981年 | 4919篇 |
| 1980年 | 4675篇 |
| 1979年 | 4803篇 |
| 1978年 | 4808篇 |
| 1977年 | 4707篇 |
| 1976年 | 4674篇 |
| 1975年 | 4583篇 |
| 1974年 | 4430篇 |
| 1973年 | 4632篇 |
| 1972年 | 2622篇 |
| 1971年 | 1908篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
81.
82.
83.
84.
85.
86.
The structure, chemical composition, and magnetic properties of electrochemically deposited nanocrystalline Co-Ni-Fe films
were investigated using a number of techniques. A high saturation magnetic induction up to B
s
= 21 kG was attained. An enhancement of the saturation magnetization compared to the ideal anticipated one was revealed,
which correlated with the nonlinear behavior of the structural phase composition and lattice parameters with the change of
the composition.
The text was submitted by the authors in English. 相似文献
87.
N. I. Golovina G. N. Nechiporenko G. G. Nemtsev G. P. Dolganova V. P. Roshchupkin D. B. Lempert G. B. Manelis 《Russian Journal of Applied Chemistry》2007,80(1):24-30
Methods for phase stabilization of ammonium nitrate were sought for in order to considerably expand the application area of this oxidizing agent in various-purpose self-combustible formulations, including that in a new generation of gas-generating formulations for automobile air bags. New methods for stabilization of ammonium nitrate were studied and, in particular, a search was made for organic compounds that can stabilize ammonium nitrate even at their low content. The mechanism of phase state stabilization of ammonium nitrate by compounds of this kind was examined. 相似文献
88.
Yu. V. Pokonova 《Russian Journal of Applied Chemistry》2007,80(12):2163-2164
Kinetic, sorption and selectivity properties of commercial adsorbents are improved by adding petroleum residues (tar asphaltene concentrates) 13% of whole mass. Obtained adsorbents can be used for selective extraction of nobel metals from multicomponent polymetallic solutions of heavy metals and fro sewages purification for removing arsenic. 相似文献
89.
Padavattan Govindaswamy Patrick J. Carroll Yurij A. Mozharivskyj Mohan Rao Kollipara 《Journal of Chemical Sciences》2006,118(4):319-326
The reaction of [{(η5-C5Me5)M(μ-Cl)Cl}2] {where M = Rh (1), Ir (2)} with functionalized phosphine viz., diphenyl-2-pyridylphosphine (PPh2Py) in dichloromethane solvent yield neutral ϰ1-P-coordinated rhodium and iridium complexes [(η5-C5Me5)RhCl2(κ1-P-PPh2Py)]3 and [(η5-C5Me5) IrCl2(ϰ1-P-PPh2Py)]4. Reaction of complexes 1 and 2 with the ligand PPh2Py in methanol under reflux give bis-substituted complexes such as [(η5-C5Me5)RhCl(ϰ1-P-PPh2Py)2]+
5 and [(η5-C5Me5)IrCl(ϰ1-P-PPh2Py)2]+
6, whereas stirring in methanol at room temperature gives P-, N-chelating complexes of the type [(η5-C5Me5)RhCl(ϰ2-P-N-PPh2Py)]+ 7 and [(η5-C5Me5)IrCl(ϰ2-P-N-PPh2Py)]+
8. Neutral ϰ1-P-coordinated complexes [(η5-C5Me5)RhCl2(ϰ1-P-PPh2Py)]3 and [(η5-C5Me5)IrCl2(ϰ1-P-PPh2Py)]4 easily undergo conversion to the cationic P-, N-chelating complexes [(η5-C5Me5)RhCl(ϰ2-P-N-PPh2Py)]+
7 and [(η5-C5Me5) IrCl(ϰ2-P, N-PPh2Py)]+
8 on stirring in methanol at room temperature. These complexes are characterized by FT-IR and FT-NMR spectroscopy as well as
analytical methods. The molecular structures of the representative complexes [(η5-C5Me5)RhCl2(ϰ1-P-PPh2Py)]3, [(η5-C5Me5)IrCl2(ϰ1-P-PPh2Py)]4 and hexafluorophosphate salt of complex [(η5-C5Me5)IrCl(ϰ2-P-PPh2Py)2]+
6 are established by single-crystal X-ray diffraction methods 相似文献
90.
The European Physical Journal E - The isothermal gas adsorption of two hexane isomers (n-hexane and cyclohexane) in the mesopores of MCM-41 silica have been investigated by small angle neutron... 相似文献