全文获取类型
收费全文 | 184531篇 |
免费 | 30493篇 |
国内免费 | 18810篇 |
专业分类
化学 | 124363篇 |
晶体学 | 1887篇 |
力学 | 12541篇 |
综合类 | 978篇 |
数学 | 23055篇 |
物理学 | 71010篇 |
出版年
2024年 | 400篇 |
2023年 | 3374篇 |
2022年 | 5197篇 |
2021年 | 6178篇 |
2020年 | 7102篇 |
2019年 | 6781篇 |
2018年 | 5986篇 |
2017年 | 5523篇 |
2016年 | 8552篇 |
2015年 | 8186篇 |
2014年 | 10018篇 |
2013年 | 13307篇 |
2012年 | 16328篇 |
2011年 | 17196篇 |
2010年 | 11458篇 |
2009年 | 10998篇 |
2008年 | 11930篇 |
2007年 | 10822篇 |
2006年 | 10001篇 |
2005年 | 8353篇 |
2004年 | 6405篇 |
2003年 | 5021篇 |
2002年 | 4673篇 |
2001年 | 3883篇 |
2000年 | 3436篇 |
1999年 | 4019篇 |
1998年 | 3452篇 |
1997年 | 3266篇 |
1996年 | 3431篇 |
1995年 | 2874篇 |
1994年 | 2583篇 |
1993年 | 2131篇 |
1992年 | 1940篇 |
1991年 | 1701篇 |
1990年 | 1437篇 |
1989年 | 1073篇 |
1988年 | 870篇 |
1987年 | 698篇 |
1986年 | 702篇 |
1985年 | 580篇 |
1984年 | 406篇 |
1983年 | 288篇 |
1982年 | 243篇 |
1981年 | 191篇 |
1980年 | 142篇 |
1979年 | 75篇 |
1978年 | 67篇 |
1977年 | 69篇 |
1976年 | 68篇 |
1974年 | 60篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Yuwei Wang Jia-Jun Yan Shengnan Hu Prof. David James Young Prof. Hong-Xi Li Prof. Zhi-Gang Ren 《化学:亚洲杂志》2021,16(18):2681-2686
A photoluminescent bimetallic cluster [Ag10Cu6(bdppthi)2(C≡CPh)12(MeOH)2(H2O)](ClO4)4 ( 1 , bdppthi=N,N’-bis(diphenylphosphanylmethyl)-tetrahydroimidazole} was synthesized from the PNNP type ligand bdppthi generated in-situ. Upon excitation at 365 nm, 1 exhibited strong phosphorescent emission at 630 nm, which was selectively quenched by NH3 in air or water. The sensing of NH3 was rapid and recoverable, with detection limits of 53 ppm (v/v) in N2 and 21 μmol/L (0.36 ppm, w/w) for NH3 ⋅ H2O in water. Cluster 1 could potentially serve as a bifunctional chemical sensor for the efficient detection of ammonia in waste-gas and waste-water. 相似文献
82.
Du Yongbo Yu Pengfei Wang Junxiong Zhang Jinping Wang Chang’an Che Defu 《Journal of Thermal Analysis and Calorimetry》2021,143(1):327-334
Journal of Thermal Analysis and Calorimetry - Coal O2/CO2 combustion is a promising carbon capture and storage technology for coal-fired power plant. Char consumption rate prediction is essential... 相似文献
83.
Nonlinear Dynamics - Under investigation is a generalized (3 + 1)-dimensional variable- coefficient Kadomtsev– Petviashvili equation in fluid mechanics. Various exact analytical solutions are... 相似文献
84.
The biodegradability of phtalic acid esters in marine and freshwater environments was characterized by their binding free energy with corresponding degrading enzymes. According to comprehensive biodegradation effects weights, the binding free energy values were converted into dimensionless efficacy coefficient using ratio normalization method. Then, considering comprehensive dual biodegradation effects value and the structural parameters of PAEs in both marine and freshwater environments, a 3D-QSAR pharmacophore model was constructed, five PAE derivatives (DBP−COOH, DBP−CHO, DBP−OH, DINP−NH2, and DINP−NO2) were screened out based on their environmental friendliness, functionality and stability. The prediction of biodegradation effects on five PAE derivatives by biodegradation models in marine and freshwater environment increased by 15.90 %, 15.84 %, 27.21 %, 12.33 %, and 8.32 %, and 21.57 %, 15.21 %, 20.99 %, 15.10 %, and 9.74 %, respectively. By simulating the photodegradation path of the PAE derivative molecular, it was found that DBP−OH can generate .OH and provides free radicals for the photodegradation of microplastics in the environment. 相似文献
85.
86.
87.
88.
89.
Terahertz(THz) wave emission from argon atom in a two-color laser pulses is studied numerically by solving the one-dimensional(1D) time-dependent Schr ¨odinger equation. The THz spectra we obtained include both discontinuous and continuum ones. By using the special basis functions that we previously proposed, our analysis points out that the discontinuous and continuum parts are contributed by bound–bound and continuum–continuum transition of atomic energy levels. Although the atomic wave function is strongly dressed during the interaction with laser fields, our identification for the discontinuous part of the THz wave shows that the transition between highly excited bound states can still be well described by the field-free basis function in the tunneling ionization regime. 相似文献
90.
Rajkumar P. Diwakar K. Subadevi R. Gnanamuthu R. M. Wang Fu-Ming Liu Wei-Ren Sivakumar M. 《Journal of Solid State Electrochemistry》2021,25(3):939-948
Journal of Solid State Electrochemistry - The “shuttle effect” of polysulfides is a serious issue, resulting in a decrease in the life-cycle of lithium-sulfur (Li-S) batteries. To... 相似文献