全文获取类型
收费全文 | 128462篇 |
免费 | 1672篇 |
国内免费 | 490篇 |
专业分类
化学 | 71073篇 |
晶体学 | 2056篇 |
力学 | 5047篇 |
综合类 | 5篇 |
数学 | 12718篇 |
物理学 | 39725篇 |
出版年
2016年 | 1369篇 |
2015年 | 1068篇 |
2014年 | 1391篇 |
2013年 | 4945篇 |
2012年 | 3621篇 |
2011年 | 4703篇 |
2010年 | 2868篇 |
2009年 | 2633篇 |
2008年 | 4182篇 |
2007年 | 4217篇 |
2006年 | 4308篇 |
2005年 | 4212篇 |
2004年 | 3657篇 |
2003年 | 3342篇 |
2002年 | 3212篇 |
2001年 | 3620篇 |
2000年 | 2716篇 |
1999年 | 2228篇 |
1998年 | 1922篇 |
1997年 | 1923篇 |
1996年 | 1873篇 |
1995年 | 1808篇 |
1994年 | 1580篇 |
1993年 | 1563篇 |
1992年 | 1783篇 |
1991年 | 1761篇 |
1990年 | 1703篇 |
1989年 | 1703篇 |
1988年 | 1710篇 |
1987年 | 1691篇 |
1986年 | 1605篇 |
1985年 | 2180篇 |
1984年 | 2290篇 |
1983年 | 1904篇 |
1982年 | 2246篇 |
1981年 | 2052篇 |
1980年 | 2096篇 |
1979年 | 2085篇 |
1978年 | 2204篇 |
1977年 | 2104篇 |
1976年 | 2131篇 |
1975年 | 2065篇 |
1974年 | 1907篇 |
1973年 | 2108篇 |
1972年 | 1270篇 |
1971年 | 966篇 |
1970年 | 902篇 |
1969年 | 922篇 |
1968年 | 1052篇 |
1967年 | 1103篇 |
排序方式: 共有10000条查询结果,搜索用时 58 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.
Dr. Kyung-Seok Kang Dr. Krishnan A. Iyer Prof. Dr. Jeffrey Pyun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(35):e202200115
In this concept review, the fundamental and polymerization chemistry of inverse vulcanization for the preparation of statistical and segmented sulfur copolymers, which have been actively developed and advanced in various applications over the past decade is discussed. This concept review delves into a discussion of step-growth polymerization constructs to describe the inverse vulcanization process and discuss prepolymer approaches for the synthesis of segmented sulfur polyurethanes. Furthermore, this concept review discusses the advantages of inverse vulcanization in conjunction with dynamic covalent polymerization and post-polymerization modifications to prepare segmented block copolymers with enhanced thermomechanical and flame retardant properties of these materials. 相似文献
3.
4.
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
5.
6.
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
7.
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
8.
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9.
10.