全文获取类型
收费全文 | 530521篇 |
免费 | 3587篇 |
国内免费 | 1110篇 |
专业分类
化学 | 242259篇 |
晶体学 | 8153篇 |
力学 | 30106篇 |
综合类 | 3篇 |
数学 | 81266篇 |
物理学 | 173431篇 |
出版年
2020年 | 4567篇 |
2019年 | 5434篇 |
2018年 | 12667篇 |
2017年 | 13027篇 |
2016年 | 12707篇 |
2015年 | 5660篇 |
2014年 | 9566篇 |
2013年 | 20068篇 |
2012年 | 18437篇 |
2011年 | 26427篇 |
2010年 | 18864篇 |
2009年 | 19107篇 |
2008年 | 24146篇 |
2007年 | 26296篇 |
2006年 | 16339篇 |
2005年 | 17620篇 |
2004年 | 15192篇 |
2003年 | 14433篇 |
2002年 | 13477篇 |
2001年 | 13239篇 |
2000年 | 10508篇 |
1999年 | 7807篇 |
1998年 | 7018篇 |
1997年 | 6827篇 |
1996年 | 6503篇 |
1995年 | 5780篇 |
1994年 | 5754篇 |
1993年 | 5853篇 |
1992年 | 6024篇 |
1991年 | 6459篇 |
1990年 | 6248篇 |
1989年 | 6211篇 |
1988年 | 5986篇 |
1987年 | 5951篇 |
1986年 | 5536篇 |
1985年 | 6958篇 |
1984年 | 7421篇 |
1983年 | 6105篇 |
1982年 | 6498篇 |
1981年 | 6150篇 |
1980年 | 5855篇 |
1979年 | 6338篇 |
1978年 | 6528篇 |
1977年 | 6469篇 |
1976年 | 6625篇 |
1975年 | 6121篇 |
1974年 | 5993篇 |
1973年 | 6239篇 |
1972年 | 4828篇 |
1971年 | 4214篇 |
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
61.
Crystallography Reports - Some questions related to the establishment, development, and prospects of physical studies using inelastic thermal-neutron scattering are briefly reviewed. The directions... 相似文献
62.
Avrutskiy V. I. Ishkhanyan A. M. Krainov V. P. 《Theoretical and Mathematical Physics》2021,208(3):1201-1206
Theoretical and Mathematical Physics - The fractional derivative method is used to take wave dispersion into account in the wave equation when describing the propagation of gravitational soliton... 相似文献
63.
S. Venkatesan S. Suresh P. Ramu M. Kandasamy J. Arumugam S. Thambidurai K.M. Prabu N. Pugazhenthiran 《印度化学会志》2022,99(5):100436
A facile biosynthesis route was followed to prepare zinc oxide nanoparticles (ZnO NPs) using Euphorbia milii (E. milii) leaf constituents. The SEM images exhibited presence of spherical ZnO NPs and the corresponding TEM images disclosed monodisperse nature of the ZnO NPs with diameter ranges between 12 and 20 nm. The Brunauer–Emmett–Teller (BET) analysis revealed that the ZnO NPs have specific surface area of 20.46 m2/g with pore diameter of 2 nm–10 nm and pore volume of 0.908 cm3/g. The EDAX spectrum exemplified the existence of Zn and O elements and non-appearance of impurities that confirmed pristine nature of the ZnO NPs. The XRD pattern indicated crystalline peaks corresponding to hexagonal wurtzite structured ZnO with an average crystallite size of 16.11 nm. The FTIR spectrum displayed strong absorption bands at 512 and 534 cm?1 related to ZnO. The photocatalytic action of ZnO NPs exhibited noteworthy degradation of methylene blue dye under natural sunlight illumination. The maximum degradation efficiency achieved was 98.17% at an illumination period of 50 min. The reusability study proved considerable photostability of the ZnO NPs during photocatalytic experiments. These findings suggest that the E. milii leaf constituents can be utilized as suitable biological source to synthesis ZnO NPs for photocatalytic applications. 相似文献
64.
Crystallography Reports - Methods of coherent X-ray diffraction imaging of the spatial structure of noncrystalline objects and nanocrystals (nanostructures) are considered. Particular attention is... 相似文献
65.
Satyanarayana A. V. S. Rao M. Jagannadha Mouli K. Chandra 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(3):1509-1513
Journal of Radioanalytical and Nuclear Chemistry - 相似文献
66.
Sun Guo-Hua Dong Qian Bezerra V. B. Dong Shi-Hai 《Journal of mathematical chemistry》2022,60(4):605-612
Journal of Mathematical Chemistry - The analytical solutions of an asymmetric double well potential $$V(x)=a\, x^2-b\, x^3+c\, x^4$$ are found to be a triconfluent Heun function $$H_{T}(\alpha ,... 相似文献
67.
68.
Physics of Particles and Nuclei Letters - When creating accelerators and storage-ring installations in a compact space, there is not always enough space for all the necessary magnet elements. In... 相似文献
69.
Dr. Kathiravan Murugesan Vishwas G. Chandrashekhar Dr. Carsten Kreyenschulte Prof. Dr. Matthias Beller Dr. Rajenahally V. Jagadeesh 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(40):17561-17565
Herein, we report the synthesis of specific silica-supported Co/Co3O4 core–shell based nanoparticles prepared by template synthesis of cobalt-pyromellitic acid on silica and subsequent pyrolysis. The optimal catalyst material allows for general and selective hydrogenation of pyridines, quinolines, and other heteroarenes including acridine, phenanthroline, naphthyridine, quinoxaline, imidazo[1,2-a]pyridine, and indole under comparably mild reaction conditions. In addition, recycling of these Co nanoparticles and their ability for dehydrogenation catalysis are showcased. 相似文献
70.
Dr. Yulia Y. Enakieva Dr. Anna A. Sinelshchikova Prof. Mikhail S. Grigoriev Prof. Vladimir V. Chernyshev Dr. Konstantin A. Kovalenko Prof. Irina A. Stenina Prof. Andrey B. Yaroslavtsev Prof. Yulia G. Gorbunova Prof. Aslan Y. Tsivadze 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(45):10552-10556
The design of new solid-state proton-conducting materials is a great challenge for chemistry and materials science. Herein, a new anionic porphyrinylphosphonate-based MOF ( IPCE-1Ni ), which involves dimethylammonium (DMA) cations for charge compensation, is reported. As a result of its unique structure, IPCE-1Ni exhibits one of the highest value of the proton conductivity among reported proton-conducting MOF materials based on porphyrins (1.55×10−3 S cm−1 at 75 °C and 80 % relative humidity). 相似文献