全文获取类型
收费全文 | 194篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
化学 | 87篇 |
力学 | 17篇 |
数学 | 28篇 |
物理学 | 69篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 10篇 |
2014年 | 4篇 |
2013年 | 9篇 |
2012年 | 14篇 |
2011年 | 9篇 |
2010年 | 9篇 |
2009年 | 5篇 |
2008年 | 11篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 9篇 |
1995年 | 4篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有201条查询结果,搜索用时 15 毫秒
131.
132.
A simple and efficient procedure for the preparation of silica‐bonded propyl‐diethylene‐triamine‐N‐sulfamic acid (SPDTSA) by reaction of 3‐diethylenetriamine‐propylsilica (DTPS) and chlorosulfonic acid in chloroform is described. Silica‐bonded propyl‐diethylene‐triamine‐N‐sulfamic acid is employed as a recyclable catalyst for the synthesis of 1,1‐diacetates from aromatic aldehydes and acetic anhydride under mild and solvent‐free conditions at room temperature. Catalyst could be recycled for several times without any additional treatment. 相似文献
133.
Quantum chemical calculations on possible decomposition processes for ladderane lipids are described. Based on the results of these calculations, it is proposed that hydrogen atom abstraction next to the ladderane core can lead to opening of the cyclobutane rings comprising the ladderane substructure, and protonation leads directly to fragmentation. Potential biological implications of these processes are discussed. 相似文献
134.
135.
136.
137.
Alves GA Amato S Anjos JC Appel JA Bracker SB Cremaldi LM Darling CL Dixon RL Errede D Fenker HC Gay C Green DR Jedicke R Kaplan D Karchin PE Kwan S Leedom I Lueking LH Luste GJ Mantsch PM de Mello Neto JR Metheny J Milburn RH de Miranda JM da Motta Filho H Napier A d'Olivera AB Rafatian A dos Reis AC Reucroft S Ross WR Santoro AF Sheaff M Souza MH Spalding WJ Stoughton C Streetman ME Summers DJ Takach SF Wu Z 《Physical review letters》1992,69(22):3147-3150
138.
139.
140.
Adsorption of different aromatic compounds (two of them are electrolytes) onto an untreated activated carbon (F100) is investigated. The experimental isotherms are fitted into Langmuir homogenous and heterogeneous Model. Theoretical maximum adsorption capacities that are based on the BET surface area of the adsorbent cannot be close to the real value. The affinity and the heterogeneity of the adsorption system observed to be related to the pKa of the solutes. The maximum adsorption capacity (Q
max) of activated carbon for each solute dependent on the molecular area as well as the type of functional group attached on the aromatic compound and also pH of solution. The arrangement of the molecules on the carbon surface is not face down. Furthermore, it is illustrated that the packing arrangement is most likely edge to face (sorbate-sorbent) with various tilt angles.For characterization of the carbon, the N2 and CO2 adsorption were used. X-ray Photoelectron Spectroscopy (XPS) measurement was used to surface elemental analysis of activated carbon. 相似文献