全文获取类型
收费全文 | 242175篇 |
免费 | 2755篇 |
国内免费 | 862篇 |
专业分类
化学 | 130043篇 |
晶体学 | 3689篇 |
力学 | 9889篇 |
综合类 | 2篇 |
数学 | 27044篇 |
物理学 | 75125篇 |
出版年
2020年 | 1764篇 |
2019年 | 2036篇 |
2018年 | 2469篇 |
2017年 | 2399篇 |
2016年 | 3817篇 |
2015年 | 2586篇 |
2014年 | 3890篇 |
2013年 | 11145篇 |
2012年 | 8065篇 |
2011年 | 9996篇 |
2010年 | 6566篇 |
2009年 | 6462篇 |
2008年 | 8973篇 |
2007年 | 9129篇 |
2006年 | 8373篇 |
2005年 | 7824篇 |
2004年 | 6985篇 |
2003年 | 6201篇 |
2002年 | 6134篇 |
2001年 | 7196篇 |
2000年 | 5360篇 |
1999年 | 4217篇 |
1998年 | 3549篇 |
1997年 | 3577篇 |
1996年 | 3288篇 |
1995年 | 3131篇 |
1994年 | 2945篇 |
1993年 | 3002篇 |
1992年 | 3292篇 |
1991年 | 3327篇 |
1990年 | 3144篇 |
1989年 | 3100篇 |
1988年 | 3161篇 |
1987年 | 3030篇 |
1986年 | 2924篇 |
1985年 | 3985篇 |
1984年 | 4145篇 |
1983年 | 3398篇 |
1982年 | 3749篇 |
1981年 | 3645篇 |
1980年 | 3518篇 |
1979年 | 3552篇 |
1978年 | 3777篇 |
1977年 | 3606篇 |
1976年 | 3814篇 |
1975年 | 3387篇 |
1974年 | 3517篇 |
1973年 | 3819篇 |
1972年 | 2328篇 |
1971年 | 1786篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
V. A. Bespalov V. M. Glazov E. A. Il’ichev Yu. A. Klimov S. V. Kuklev A. E. Kuleshov R. M. Nabiev G. N. Petrukhin B. G. Potapov G. S. Rychkov D. S. Sokolov V. V. Fandeev E. A. Fetisov S. S. Yakushov 《Technical Physics》2015,60(4):553-560
The results of investigation of optical image detectors designed for the largest problem, near-VUV, range of the spectrum are presented. The possibility of using a dual-stage image detection system to appreciably lower the sensitivity threshold and make computer data processing feasible is considered. The integration of a UV module into a wideband image detector is studied. 相似文献
32.
A. Lashgari S. Ghammamy R. Ramirez-Tagle G. Salgado-Moran 《Journal of Structural Chemistry》2015,56(8):1505-1513
Two new compounds of fluorine: (C2H5)4N[I2F] and (C2H5)4N[Br2F], have been easily synthesized in a nearly quantitative by a direct reaction of (C2H5)4NF, I2 and Br2. The products were isolated and characterized by elemental analysis and spectroscopic methods such as: Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy (UV-Vis). These compounds have been studied computationally with the Scalar ZORA relativistic level of theory using the ADF program package. The molecular parameters, and vibrational spectra were calculated. The excitation energies were found by timedependent perturbation density functional theory (TD-DFT). Molecule optimization, frequencies and excitation energies were calculated with standard Slatertype-orbital (STO) basis sets with triple-zeta quality double plus polarization functions (TZ2P) for all atoms. The FTIR, UV-Vis spectra and assignment of principal transitions and total density of state (TDOS) were extracted using the GaussSum 2.2 program. The comparison between experimental and calculated values showes that the experimental results correlate well with the predicted data. 相似文献
33.
Khusnutdinov R. I. Shchadneva N. A. Mayakova Yu. Yu. Aminov R. I. 《Russian Journal of Organic Chemistry》2021,57(6):950-953
Russian Journal of Organic Chemistry - Binder-free iron- and nickel-containing micro-, meso-, and macroporous zeolites FeHY and NiHY were found to effectively catalyze Knoevenagel condensation of... 相似文献
34.
Farsi R. Mohammadi M. K. Saghanezhad S. J. 《Russian Journal of Organic Chemistry》2021,57(12):2002-2009
Russian Journal of Organic Chemistry - Herein, we report the sulfonamide-functionalized covalent organic framework (COF-SO3H), prepared by condensation of melamine and terephthalaldehyde and... 相似文献
35.
36.
37.
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
38.
Dhanapal Kalaimegam Raman Mohan Kamatchi R. Kumaresan G. 《Journal of Thermal Analysis and Calorimetry》2021,144(1):233-243
Journal of Thermal Analysis and Calorimetry - The role of method of synthesis on the size of flakes, dispersion stability and thermophysical properties of aqua based reduced graphene oxide (rGO)... 相似文献
39.
40.