全文获取类型
收费全文 | 322075篇 |
免费 | 3597篇 |
国内免费 | 947篇 |
专业分类
化学 | 182813篇 |
晶体学 | 4421篇 |
力学 | 12877篇 |
综合类 | 11篇 |
数学 | 37647篇 |
物理学 | 88850篇 |
出版年
2020年 | 2625篇 |
2019年 | 2824篇 |
2018年 | 3525篇 |
2017年 | 3528篇 |
2016年 | 5368篇 |
2015年 | 3536篇 |
2014年 | 5276篇 |
2013年 | 12831篇 |
2012年 | 10143篇 |
2011年 | 12504篇 |
2010年 | 8477篇 |
2009年 | 8104篇 |
2008年 | 11483篇 |
2007年 | 11743篇 |
2006年 | 11185篇 |
2005年 | 10205篇 |
2004年 | 9353篇 |
2003年 | 8360篇 |
2002年 | 8180篇 |
2001年 | 7945篇 |
2000年 | 6250篇 |
1999年 | 4913篇 |
1998年 | 4398篇 |
1997年 | 4454篇 |
1996年 | 4198篇 |
1995年 | 3832篇 |
1994年 | 4017篇 |
1993年 | 3717篇 |
1992年 | 4118篇 |
1991年 | 4099篇 |
1990年 | 4003篇 |
1989年 | 3862篇 |
1988年 | 4000篇 |
1987年 | 3912篇 |
1986年 | 3715篇 |
1985年 | 4993篇 |
1984年 | 5333篇 |
1983年 | 4340篇 |
1982年 | 4613篇 |
1981年 | 4509篇 |
1980年 | 4624篇 |
1979年 | 4480篇 |
1978年 | 5498篇 |
1977年 | 5148篇 |
1976年 | 4700篇 |
1975年 | 4255篇 |
1974年 | 4300篇 |
1973年 | 4421篇 |
1972年 | 3123篇 |
1971年 | 2607篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Physics of Atomic Nuclei - We have studied the mechanisms influencing production of cumulative pions and protons in the fragmentation of the incident deuterons into cumulative pions and protons... 相似文献
62.
Dhanapal Kalaimegam Raman Mohan Kamatchi R. Kumaresan G. 《Journal of Thermal Analysis and Calorimetry》2021,144(1):233-243
Journal of Thermal Analysis and Calorimetry - The role of method of synthesis on the size of flakes, dispersion stability and thermophysical properties of aqua based reduced graphene oxide (rGO)... 相似文献
63.
Ramesh G. K. Manjunatha S. Roopa G. S. Chamkha Ali J. 《Journal of Thermal Analysis and Calorimetry》2021,146(3):1347-1357
Journal of Thermal Analysis and Calorimetry - Modeling and computations are performed to study the ND-Co3O4/EG hybrid nanoliquid mixed convective flow past a vertical porous cylinder. The flow... 相似文献
64.
Mechanistic Aspects of a Highly Active Dinuclear Zinc Catalyst for the Co‐polymerization of Epoxides and CO2
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Stefan Kissling Peter T. Altenbuchner Dr. Maximilian W. Lehenmeier Dr. Eberhardt Herdtweck Dr. Peter Deglmann Dr. Uwe B. Seemann Prof. Dr. Bernhard Rieger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8148-8157
The dinuclear zinc complex reported by us is to date the most active zinc catalyst for the co‐polymerization of cyclohexene oxide (CHO) and carbon dioxide. However, co‐polymerization experiments with propylene oxide (PO) and CO2 revealed surprisingly low conversions. Within this work, we focused on clarification of this behavior through experimental results and quantum chemical studies. The combination of both results indicated the formation of an energetically highly stable intermediate in the presence of propylene oxide and carbon dioxide. A similar species in the case of cyclohexene oxide/CO2 co‐polymerization was not stable enough to deactivate the catalyst due to steric repulsion. 相似文献
65.
66.
67.
G. Grätzer 《Algebra Universalis》2015,74(3-4):351-359
68.
Inside Cover: Ru‐Catalysed CH Arylation of Indoles and Pyrroles with Boronic Acids: Scope and Mechanistic Studies (Chem. Eur. J. 14/2015)
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
69.
Robert G. W. Anderson 《Ambix》2015,62(4):333-344
Following colonisation of South America by the Spanish, many new naturally occurring substances were sent to Europe. One of these was the silvery, unreactive metal, platinum, discovered in New Grenada in the mid-eighteenth century. It was often found in granular form, associated with gold, and the challenge to chemists was to refine it, produce it as wire or sheet, and determine its chemical properties. This interested the professor of chemistry at the University of Edinburgh, Joseph Black, who was able to obtain samples from London-based Spanish contacts, particularly Ignacio Luzuriaga. This paper examines how Black transmitted his knowledge of the metal to large numbers of students attending his annual course. 相似文献
70.