全文获取类型
收费全文 | 5012篇 |
免费 | 129篇 |
国内免费 | 7篇 |
专业分类
化学 | 2947篇 |
晶体学 | 125篇 |
力学 | 167篇 |
数学 | 393篇 |
物理学 | 1516篇 |
出版年
2023年 | 32篇 |
2022年 | 110篇 |
2021年 | 107篇 |
2020年 | 114篇 |
2019年 | 123篇 |
2018年 | 120篇 |
2017年 | 159篇 |
2016年 | 190篇 |
2015年 | 135篇 |
2014年 | 182篇 |
2013年 | 391篇 |
2012年 | 298篇 |
2011年 | 312篇 |
2010年 | 212篇 |
2009年 | 188篇 |
2008年 | 247篇 |
2007年 | 211篇 |
2006年 | 146篇 |
2005年 | 147篇 |
2004年 | 115篇 |
2003年 | 100篇 |
2002年 | 108篇 |
2001年 | 60篇 |
2000年 | 53篇 |
1999年 | 36篇 |
1998年 | 33篇 |
1997年 | 38篇 |
1996年 | 43篇 |
1995年 | 29篇 |
1994年 | 33篇 |
1993年 | 43篇 |
1992年 | 51篇 |
1991年 | 36篇 |
1990年 | 40篇 |
1989年 | 49篇 |
1988年 | 44篇 |
1987年 | 42篇 |
1986年 | 32篇 |
1985年 | 61篇 |
1984年 | 57篇 |
1983年 | 40篇 |
1982年 | 44篇 |
1981年 | 51篇 |
1980年 | 45篇 |
1979年 | 46篇 |
1978年 | 43篇 |
1977年 | 51篇 |
1976年 | 54篇 |
1975年 | 44篇 |
1974年 | 38篇 |
排序方式: 共有5148条查询结果,搜索用时 46 毫秒
21.
22.
Our main object in this paper is to discuss some results on rings with left identity in which certain subsets satisfy some functional identities. 相似文献
23.
Excess enthalpies of mixing H
m
E
of tetrahydrofuran and tetrahydropyran with trichloromethane, tetrachloromethane, 1,2-dichloroethane, 1,1,2-trichloroethane and 1,1,2,2-tetrachloroethane have been determined at 26.9°C and are found to be negative over the entire composition range for both sets of the ether mixtures. H
m
E
decreases in the sequence; dichloroethane > tetrachloromethane > trichloroethane > trichloromethane > tetrachloroethane. The results are explained on the basis of strong O...H-C and weak Cl...O specific interactions. Flory's theory has been used to correlate the experimental data with good agreement found between the theoretical and experimental values of H
m
E
. 相似文献
24.
M K Parida Nita Sinha B Adhikary B Allanach A Alok K S Babu B Brahmachari D Choudhury E J Chun P K Das A Ghosal D Hitlin W S Hou S Kumar H N Li E Ma S K Majee G Majumdar B Mishra G Mohanty S Nandi H Pas M K Parida S D Rindani J P Saha N Sahu Y Sakai S Sen C Sharma C D Sharma S Shalgar N N Singh S Uma Sankar N Sinha R Sinha F Simonetto R Srikanth R Vaidya 《Pramana》2006,67(5):849-860
This is the report of flavor physics and model building working group at WHEPP-9. While activites in flavor physics have been
mainly focused on B-physics, those in model building have been primarily devoted to neutrino physics. We present summary of working group discussions
carried out during the workshop in the above fields, and also briefly review the progress made in some projects subsequently. 相似文献
25.
Recent X-ray diffraction studies on α-quartz (SiO2) by Kingmaet al [1], have shown the occurrence of a reversible, crystalline-to-crystalline, phase transition just prior to amorphization
at ≈ 21 GPa. This precursor transition has also been confirmed by our recent molecular dynamics simulation study [2]. In order
to investigate the possibility of a similar behaviour in other isostructural compounds, which also undergo pressure induced
amorphization, α-GeO2 and α-AlPO4 (berlinite form) were studied using energy dispersive X-ray diffraction. In either of these materials, no such phase transition
is detected prior to amorphization. The onset of amorphization and its reversal is found to be time dependent in GeO2. 相似文献
26.
27.
28.
, n- n- 1 , . , , ( « ») f . 相似文献
29.
An explicit expression has been derived for the volume dependence of electron-phonon coupling strength () by using a recently proposed quadratic form of the screened pseudopotential and by considering the variation of Fermi momentum with volume. Variation of Coulomb pseudopotential (
*) has also been explicitly considered by varying the Fermi momentum. Dependence of transition temperatureT
c
and the logarithm of the effective interaction strength (N
0
V) on the volume has been studied for eight nontransition metallic superconductors. A linear drop inT
c
for small values of (–/
0) as well as the calculated values of= InN
0
V/ In, exhibits better matching with the experimental data, as compared to the earlier theoretical results. 相似文献
30.
A 1Σ u + -X 1Σ g + emission in Na2 is observed following excitation ofB 1π u by various lines of an argon ion laser. The excitation energy ofB 1π u is collisionally transferred to the (2)1Σ g + which then radiatively populates theA 1Σ u + state. The Na vapour is contained in a stainless steel crossed heat pipe with Ar buffer gas and temperature around 600°C. For all laser lines except 4579 Å, the coarse features ofA-X emission are independent of the laser wavelength. However, at high resolution the finer differences between different laser line excitation are explained. Variousv′-v″ transitions in this emission are identified. Computer simulation is presented to help explain some features of this emission. 相似文献