全文获取类型
收费全文 | 26838篇 |
免费 | 1018篇 |
国内免费 | 167篇 |
专业分类
化学 | 17803篇 |
晶体学 | 255篇 |
力学 | 923篇 |
综合类 | 2篇 |
数学 | 2446篇 |
物理学 | 6594篇 |
出版年
2023年 | 144篇 |
2022年 | 112篇 |
2021年 | 432篇 |
2020年 | 437篇 |
2019年 | 456篇 |
2018年 | 345篇 |
2017年 | 329篇 |
2016年 | 744篇 |
2015年 | 656篇 |
2014年 | 826篇 |
2013年 | 1529篇 |
2012年 | 1990篇 |
2011年 | 2168篇 |
2010年 | 1326篇 |
2009年 | 1178篇 |
2008年 | 1788篇 |
2007年 | 1674篇 |
2006年 | 1561篇 |
2005年 | 1458篇 |
2004年 | 1283篇 |
2003年 | 986篇 |
2002年 | 852篇 |
2001年 | 629篇 |
2000年 | 507篇 |
1999年 | 282篇 |
1998年 | 201篇 |
1997年 | 246篇 |
1996年 | 302篇 |
1995年 | 265篇 |
1994年 | 272篇 |
1993年 | 280篇 |
1992年 | 264篇 |
1991年 | 207篇 |
1990年 | 152篇 |
1989年 | 143篇 |
1988年 | 142篇 |
1987年 | 118篇 |
1986年 | 96篇 |
1985年 | 174篇 |
1984年 | 124篇 |
1983年 | 103篇 |
1982年 | 131篇 |
1981年 | 94篇 |
1980年 | 86篇 |
1978年 | 96篇 |
1977年 | 110篇 |
1976年 | 100篇 |
1975年 | 112篇 |
1974年 | 83篇 |
1973年 | 106篇 |
排序方式: 共有10000条查询结果,搜索用时 146 毫秒
1.
Chong Saehwa Riley Brian J. Nienhuis Emily T. Lee Dongjin McCloy John S. 《Journal of chemical crystallography》2021,51(3):293-300
Journal of Chemical Crystallography - Four different rare-earth oxyapatites of Ca2RE8(SiO4)6O2 (RE?=?Pr, Tb, Ho, Tm) were synthesized using a solution-based method followed by drying,... 相似文献
2.
Dong Gun Oh Prof. Hristiyan A. Aleksandrov Haneul Kim Dr. Iskra Z. Koleva Dr. Konstantin Khivantsev Prof. Georgi N. Vayssilov Prof. Ja Hun Kwak 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(49):e202200684
Pd-based catalysts are the most widely used for CO oxidation because of their outstanding catalytic activity and thermal stability. However, fundamental understanding of the detailed catalytic processes occurring on Pd-based catalysts under realistic conditions is still lacking. In this study, we investigated CO oxidation on metallic Pd clusters supported on Al2O3 and SiO2. High-angle annular dark-field scanning transmission electron microscopy revealed the formation of similar-sized Pd clusters on Al2O3 and SiO2. In contrast, CO chemisorption analysis indicated a gradual change in the dispersion of Pd (from 0.79 to 0.2) on Pd/Al2O3 and a marginal change in the dispersion (from 0.4 to 0.24) on Pd/SiO2 as the Pd loading increased from 0.27 to 5.5 wt %; these changes were attributed to differences in the metal-support interactions. Diffuse reflectance infrared Fourier-transform spectroscopy revealed that fewer a-top CO species were present in Pd supported on Al2O3 than those in Pd supported on SiO2, which is related to the morphological differences in the metallic Pd clusters on these two supports. Despite the different dispersion profiles and surface characteristics of Pd, O2 titration demonstrated that linearly bound CO (with an infrared signal at 2090 cm−1) reacted first with oxygen in the case of CO-saturated Pd on Al2O3 and SiO2, which suggests that a-top CO on the terrace site plays an important role in CO oxidation. The experimental observations were corroborated by periodic density functional calculations, which confirmed that CO oxidation on the (111) terrace sites is most plausible, both kinetically and thermodynamically, compared to that on the edge or corner sites. This study will deepen the fundamental understanding of the effect of Pd clusters on CO oxidation under reaction conditions. 相似文献
3.
Science China Mathematics - We study the toric degeneration of Weyl group translated Schubert divisors of a partial flag variety $$F{\ell _{{n_1}, \ldots,{n_k};n}}$$ via Gelfand-Cetlin polytopes.... 相似文献
4.
5.
Dehghanpour-Sahron Ja’far Mahdavi-Amiri Nezam 《4OR: A Quarterly Journal of Operations Research》2021,19(4):473-499
4OR - Partitioning a given data-set into subsets based on similarity among the data is called clustering. Clustering is a major task in data mining and machine learning having many applications... 相似文献
6.
Pirozerskii A. L. Charnaya E. V. Lee M. K. Chang L.-J. Naumov S. V. Domozhirova A. N. Marchenkov V. V. 《Physics of the Solid State》2022,64(2):80-84
Physics of the Solid State - The discovery of extreme magnetoresistance (MR) in nonmagnetic materials attracted attention to WTe2 semimetal. We studied MR in a single crystal of tungsten... 相似文献
7.
Ryu Hoon-Hee Lee Soo-Been Sun Yang-Kook 《Journal of Solid State Electrochemistry》2022,26(9):2097-2105
Journal of Solid State Electrochemistry - Preparing a high-performance Ni-rich single-crystal cathode for Li-ion batteries is challenging. This is because calcination must be performed at a high... 相似文献
8.
Aysun apc Mlanie M. Lorion Hui Wang Nina Simon Maria Leidenberger Mariana C. BorgesSilva Diogo R. M. Moreira Yongping Zhu Yuqing Meng Jia Yun Chen Yew Mun Lee Oliver Friedrich Barbara Kappes Jigang Wang Lutz Ackermann Svetlana B. Tsogoeva 《Angewandte Chemie (International ed. in English)》2019,58(37):13161-13161
9.
Park Kyueun Kim Youngjin Lee Kyung Jin 《Journal of Radioanalytical and Nuclear Chemistry》2019,319(2):487-531
Journal of Radioanalytical and Nuclear Chemistry - An extensive series of evaluations have been performed as part of an IAEA coordinated research project to study a set of nuclear reactions that... 相似文献
10.
Gitae Moon Intae Son Chunho Kim Chi Hyeong Cho Eunbi Lee Eun Hyoung Bae 《Molecular Crystals and Liquid Crystals》2019,687(1):60-67
AbstractTo enable recent 3D and moving picture applications, liquid crystal displays (LCD) must exhibit fast response and wide viewing angle characteristics. Pre-tilted vertical alignment layers for high-speed LCD were fabricated using bi-functional photoreactive monomers. The monomers can be confined to the polyimide layer and photo-polymerized by UV exposure under voltage. Response characteristics of photo-controlled alignment films according to the structure were investigated. Vertical alignment properties were evaluated using a polarizing optical microscope, and electro-optical characteristics were compared through the voltage-transmittance curve and response time measurement. Faster response speed could be obtained by using photoreactive monomers having a long alkyl chain. 相似文献