全文获取类型
收费全文 | 291994篇 |
免费 | 2131篇 |
国内免费 | 886篇 |
专业分类
化学 | 124072篇 |
晶体学 | 4052篇 |
力学 | 17137篇 |
综合类 | 6篇 |
数学 | 63946篇 |
物理学 | 85798篇 |
出版年
2018年 | 18135篇 |
2017年 | 18754篇 |
2016年 | 10357篇 |
2015年 | 2725篇 |
2014年 | 1892篇 |
2013年 | 5428篇 |
2012年 | 11007篇 |
2011年 | 25478篇 |
2010年 | 14704篇 |
2009年 | 14890篇 |
2008年 | 20260篇 |
2007年 | 25583篇 |
2006年 | 4767篇 |
2005年 | 12618篇 |
2004年 | 8616篇 |
2003年 | 8508篇 |
2002年 | 5548篇 |
2001年 | 4022篇 |
2000年 | 3279篇 |
1999年 | 2403篇 |
1998年 | 2135篇 |
1997年 | 2054篇 |
1996年 | 2143篇 |
1995年 | 1996篇 |
1994年 | 1727篇 |
1993年 | 1715篇 |
1992年 | 1890篇 |
1991年 | 1899篇 |
1990年 | 1808篇 |
1989年 | 1817篇 |
1988年 | 1840篇 |
1987年 | 1824篇 |
1986年 | 1730篇 |
1985年 | 2286篇 |
1984年 | 2406篇 |
1983年 | 2031篇 |
1982年 | 2342篇 |
1981年 | 2160篇 |
1980年 | 2209篇 |
1979年 | 2208篇 |
1978年 | 2333篇 |
1977年 | 2148篇 |
1976年 | 2199篇 |
1975年 | 2124篇 |
1974年 | 1960篇 |
1973年 | 2213篇 |
1972年 | 1342篇 |
1971年 | 1012篇 |
1968年 | 1163篇 |
1967年 | 1139篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Yang T. L. Kao C. L. Kuo C. E. Yeh H. C. Li W. J. Li H. T. Chen C. Y. 《Chemistry of Natural Compounds》2022,58(5):825-827
Chemistry of Natural Compounds - A novel bibenzyl derivative, hydrangchinenin (1), was isolated from the stems of Hydrangea chinensis Maxim. (Hydrangeaceae). Its structure was determined on the... 相似文献
2.
3.
Theoretical and Mathematical Physics - Dynamic systems acting on the plane and possessing the Wada property have been observed. There exist only two topological types, symmetric and antisymmetric,... 相似文献
4.
5.
Li Y. Shi W. H. Dong L. M. Xu S. X. Huang H. J. Yin J. R. 《Journal of Applied Spectroscopy》2022,89(3):534-541
Journal of Applied Spectroscopy - Sr3B2O6:Dy3+, Eu3+ single-matrix white-light-emitting materials are prepared using the high-temperature solid-state method. The microstructure, emission spectrum,... 相似文献
6.
Ajit Kumar Singh Seulgi Ji Baghendra Singh Chittaranjan Das Heechae Choi Prashanth W. Menezes Arindam Indra 《Materials Today Chemistry》2022
Herein, we report a Mott-Schottky catalyst by entrapping cobalt nanoparticles inside the N-doped graphene shell (Co@NC). The Co@NC delivered excellent oxygen evolution activity with an overpotential of merely 248 mV at a current density of 10 mA cm–2 with promising long-term stability. The importance of Co encapsulated in NC has further been demonstrated by synthesizing Co nanoparticles without NC shell. The synergy between the hexagonal close-packed (hcp) and face-centered cubic (fcc) Co plays a major role to improve the OER activity, whereas the NC shell optimizes the electronic structure, improves the electron conductivity, and offers a large number of active sites in Co@NC. The density functional theory calculations have revealed that the hcp Co has a dominant role in the surface reaction of electrocatalytic oxygen evolution, whereas the fcc phase induces the built-in electric field at the interfaces with N-doped graphene to accelerate the H+ ion transport. 相似文献
7.
Restricted testing conditions were considered recently. For the maximal operator, Hytönen, Li and Sawyer [8] first obtained parental testing condition. Later, they [9] showed that it suffices to restrict testing to doubling cubes. Chen and Lacey [3] gave a similar restricted testing condition. In our paper, we discuss a version of the latter in the multilinear setting.
相似文献8.
Dr. Chen-Ming Lin Maritess Arancillo Jonathan Whisenant Prof. Kevin Burgess 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(24):9484-9488
Secondary structures tend to be recognizable because they have repeating structural motifs, but mimicry of these does not have to follow such well-defined patterns. Bioinformatics studies to match side-chain orientations of a novel hydantoin triazole chemotype ( 1 ) to protein-protein interfaces revealed it tends to align well across parallel and antiparallel sheets, like rungs on a ladder. One set of these overlays was observed for the protein-protein interaction uPA⋅uPAR. Consequently, chemotype 1 was made with appropriate side-chains to mimic uPA at this interface. Biophysical assays indicate these compounds did in fact bind uPAR, and elicit cellular responses that affected invasion, migration, and wound healing. 相似文献
9.
In the paper, the authors establish several integral representations for the generating functions of the large and little Schröder numbers and for the large and little Schröder numbers. 相似文献
10.