全文获取类型
收费全文 | 8298篇 |
免费 | 304篇 |
国内免费 | 59篇 |
专业分类
化学 | 4418篇 |
晶体学 | 207篇 |
力学 | 163篇 |
数学 | 630篇 |
物理学 | 3243篇 |
出版年
2023年 | 65篇 |
2022年 | 42篇 |
2021年 | 70篇 |
2020年 | 111篇 |
2019年 | 87篇 |
2018年 | 93篇 |
2017年 | 114篇 |
2016年 | 183篇 |
2015年 | 229篇 |
2014年 | 213篇 |
2013年 | 567篇 |
2012年 | 427篇 |
2011年 | 504篇 |
2010年 | 480篇 |
2009年 | 457篇 |
2008年 | 503篇 |
2007年 | 537篇 |
2006年 | 652篇 |
2005年 | 505篇 |
2004年 | 431篇 |
2003年 | 360篇 |
2002年 | 245篇 |
2001年 | 238篇 |
2000年 | 214篇 |
1999年 | 146篇 |
1998年 | 84篇 |
1997年 | 93篇 |
1996年 | 99篇 |
1995年 | 73篇 |
1994年 | 82篇 |
1993年 | 50篇 |
1992年 | 59篇 |
1991年 | 39篇 |
1990年 | 48篇 |
1989年 | 33篇 |
1988年 | 36篇 |
1987年 | 27篇 |
1986年 | 23篇 |
1985年 | 56篇 |
1984年 | 92篇 |
1983年 | 39篇 |
1982年 | 56篇 |
1981年 | 47篇 |
1980年 | 50篇 |
1979年 | 30篇 |
1978年 | 30篇 |
1977年 | 20篇 |
1976年 | 15篇 |
1975年 | 4篇 |
1936年 | 1篇 |
排序方式: 共有8661条查询结果,搜索用时 15 毫秒
1.
2.
3.
Cusinato Marco Guercilena Federico Maria Perego Albino Logoteta Domenico Radice David Bernuzzi Sebastiano Ansoldi Stefano 《The European Physical Journal A - Hadrons and Nuclei》2022,58(5):1-69
The European Physical Journal A - PUMA, antiProton Unstable Matter Annihilation, is a nuclear-physics experiment at CERN aiming at probing the surface properties of stable and rare isotopes by use... 相似文献
4.
5.
Watanabe Sou Senzaki Tatsuya Shibata Atsuhiro Nomura Kazunori Takeuchi Masayuki Nakatani Kiyoharu Matsuura Haruaki Horiuchi Yusuke Arai Tsuyoshi 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(3):1273-1277
Journal of Radioanalytical and Nuclear Chemistry - Extraction chromatography flow-sheet employing octyl(phenyl)-N,N-diisobutylcarbonoylmethylphosphine oxide and bis(2-ethylhexyl) hydrogen phosphate... 相似文献
6.
Swinhoeisterol A is a novel steroid with unusual 6/6/5/7 tetracyclic skeleton. The model compound with BCD rings is constructed by Friedel–Crafts acylation and an oxidative dearomatization as key steps. 相似文献
7.
《Operations Research Letters》2022,50(4):407-414
In this study, the existing game theoretical framework is extended to strategic queuing in search of solutions for a two-population game in observable double-ended queuing systems with zero matching times. We show that multiple Nash equilibria and one unique subgame perfect Nash equilibrium exist in this game. 相似文献
8.
Aoshima Makoto Yata Kazuyoshi 《Annals of the Institute of Statistical Mathematics》2019,71(3):473-503
Annals of the Institute of Statistical Mathematics - We consider classifiers for high-dimensional data under the strongly spiked eigenvalue (SSE) model. We first show that high-dimensional data... 相似文献
9.
Xiaopei Li Tasuku Ogihara Prof. Dr. Manabu Abe Dr. Yasuyuki Nakamura Prof. Dr. Shigeru Yamago 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(42):9846-9850
The effect of viscosity on the diffusion efficiency (Fdif) of an organic radical pair in a solvent cage and the termination mechanism, that is, the selectivity of disproportionation (Disp) and combination (Comb) of the geminated caged radical pair and the diffused radicals encountered, were investigated quantitatively by following the photolysis of dimethyl 2,2′-azobis(2-methylpropionate) (V-601) in the absence and presence of PhSD. Fdif and Disp/Comb selectivity outside the cage [Disp(dif)/Comb(dif)] are highly sensitive to the viscosity. In contrast, the Disp/Comb selectivity inside the cage [Disp(cage)/Comb(cage)] is rather insensitive. The difference in viscosity dependence between Disp(cage)/Comb(cage) and Disp(dif)/Comb(dif) is explained by the spin state of the radical pair inside and outside the cage and the spin state dependent configurational changes of the radical pair upon their collision. Given that the configurational change of the radicals associates the displacement and reorganization of solvents around the radicals, the termination outside the cage, which requires larger change than that inside the cage, is highly viscosity dependent. Furthermore, while the bulk viscosity of each solvent shows good correlation with Fdif and Disp/Comb selectivity, microviscosity is the better parameter predicting Fdif and Disp(dif)/Comb(dif) selectivity regardless of the solvents. 相似文献
10.
Hiroshi Shinotsuka Shigeo Tanuma Cedric J. Powell Dave R. Penn 《Surface and interface analysis : SIA》2019,51(4):427-457
We have calculated inelastic mean free paths (IMFPs) for 42 inorganic compounds (AgBr, AgCl, AgI, Al2O3, AlAs, AlN, AlSb, cubic BN, hexagonal BN, CdS, CdSe, CdTe, GaAs, GaN, GaP, GaSb, GaSe, InAs, InP, InSb, KBr, KCl, MgF2, MgO, NaCl, NbC0.712, NbC0.844, NbC0.93, PbS, PbSe, PbTe, SiC, SiO2, SnTe, TiC0.7, TiC0.95, VC0.76, VC0.86, Y3Al5O12, ZnS, ZnSe, and ZnTe) for electron energies from 50 eV to 200 keV. These calculations were made with energy-loss functions (ELFs) obtained from measured optical constants for 15 compounds while calculated ELFs were utilized for the other 27 compounds. Checks based on ELF sum rules showed that the calculated ELFs were superior to the measured ELFs that we had used previously. Our calculated IMFPs could be fitted to a modified form of the relativistic Bethe equation for inelastic scattering of electrons in matter for energies from 50 eV to 200 keV. The average root-mean-square (RMS) deviation in these fits was 0.60%. The IMFPs were also compared with a relativistic version of our predictive Tanuma-Powell-Penn (TPP-2M) equation. The average RMS deviation in these comparisons was 10.7% for energies between 50 eV and 200 keV. This average RMS deviation is almost the same as that found in a similar comparison for a group of 41 elemental solids (11.9%) although relatively large deviations were found for cubic BN (65.6%) and hexagonal BN (34.3%). If these two compounds are excluded in the comparisons, the average RMS deviation becomes 8.7%. We found generally satisfactory agreement between our calculated IMFPs and values from other calculations and from experiments. 相似文献