全文获取类型
收费全文 | 3672篇 |
免费 | 94篇 |
国内免费 | 16篇 |
专业分类
化学 | 2762篇 |
晶体学 | 38篇 |
力学 | 57篇 |
数学 | 197篇 |
物理学 | 728篇 |
出版年
2022年 | 36篇 |
2021年 | 30篇 |
2020年 | 50篇 |
2019年 | 61篇 |
2018年 | 42篇 |
2017年 | 20篇 |
2016年 | 69篇 |
2015年 | 47篇 |
2014年 | 68篇 |
2013年 | 157篇 |
2012年 | 158篇 |
2011年 | 225篇 |
2010年 | 96篇 |
2009年 | 118篇 |
2008年 | 199篇 |
2007年 | 209篇 |
2006年 | 225篇 |
2005年 | 210篇 |
2004年 | 178篇 |
2003年 | 142篇 |
2002年 | 142篇 |
2001年 | 76篇 |
2000年 | 62篇 |
1999年 | 60篇 |
1998年 | 40篇 |
1997年 | 41篇 |
1996年 | 56篇 |
1995年 | 53篇 |
1994年 | 31篇 |
1993年 | 38篇 |
1992年 | 47篇 |
1991年 | 33篇 |
1990年 | 33篇 |
1989年 | 37篇 |
1988年 | 49篇 |
1987年 | 37篇 |
1986年 | 35篇 |
1985年 | 70篇 |
1984年 | 45篇 |
1983年 | 34篇 |
1982年 | 35篇 |
1981年 | 39篇 |
1980年 | 35篇 |
1979年 | 47篇 |
1978年 | 36篇 |
1977年 | 31篇 |
1976年 | 22篇 |
1975年 | 28篇 |
1974年 | 34篇 |
1973年 | 27篇 |
排序方式: 共有3782条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
65.
Inoue IH Watanabe M Kinoshita T Kakizaki A Kato R Kobayashi A Kobayashi H Fujimori A 《Physical review. B, Condensed matter》1993,47(19):12917-12920
66.
67.
Wataru Ueda Damian Vitry Tomokazu Kato Nobufumi Watanabe Yusuke Endo 《Research on Chemical Intermediates》2006,32(3-4):217-233
Mo-V-O-based complex metal oxide catalysts were synthesized hydrothermally for the first time, characterized structurally and tested in the selective oxidation of propane to acrylic acid, and the results obtained were compared on the basis of catalyst crystal structures in order to clarify key aspects of alkane selective oxidation over multifunctional metal oxide catalysts. The catalysts tested were black solids of rod-shaped crystals, which had a layer structure in the direction of fiber axis and various high dimensional arrangements of metal octahedra in the cross-section plane. A strong dependency on the octahedra arrangements and a facet dependency were observed, and the roles of metal elements in the course of selective oxidation of propane were clarified by comparing the catalytic performance of various Mo-V-O-based catalysts. We discuss the multi-functional character derived from high dimensional structures of the catalysts and mechanism of the selective oxidation of propane. 相似文献
68.
A new copper dispersed ceramic-graphite composite electrode was fabricated by the initial mixing of copper nitrate and (3-mercaptopropyl)trimethoxy silane (MPS) followed by stirring with graphite powder. The combination of the metal catalysis and the advantages of the ceramic composite favored the electrocatalytic reduction of hydrogen peroxide (H2O2) at a reduced overpotential of -0.2 V with good sensitivity, stability and reproducibility. The sensor showed a good linear response to H2O2 in the range from 8.3 x 10(-6) M to 2.0 x 10(-3) M with a correlation coefficient of 0.9989 and the detection limit was 6.2 x 10(-6) M (S/N =3). 相似文献
69.
Several beta-secretase inhibitors were designed based on hydroxyethylamine dipeptide isostere (HDI) structures and were synthesized by a methodology using the aza-Payne rearragement and O,N-acyl transfer reactions to study their structure-activity relationships. Among these pseudopeptides, effective compounds were developed as the first beta-secretase inhibitors containing the HDI transition state mimic with potent enzyme inhibitory activity (IC50 < 100 nM). 相似文献
70.
Masanori Yamaguchi Kaoru Kojima Ikuko Kakizaki Keiichi Takagaki 《Tetrahedron letters》2006,47(42):7455-7458
Efficient constructions of two types of neo-proteoglycan are described. Enzymatically prepared alkyne containing chondroitin 6-sulfate chains and chemically synthesized azido group having compounds are linked by utilizing the copper(I) catalyzed 1,3-dipolar cycloaddition. 相似文献