全文获取类型
收费全文 | 483篇 |
免费 | 14篇 |
国内免费 | 1篇 |
专业分类
化学 | 388篇 |
晶体学 | 3篇 |
力学 | 11篇 |
数学 | 46篇 |
物理学 | 50篇 |
出版年
2023年 | 3篇 |
2022年 | 14篇 |
2021年 | 25篇 |
2020年 | 10篇 |
2019年 | 12篇 |
2018年 | 11篇 |
2017年 | 9篇 |
2016年 | 14篇 |
2015年 | 22篇 |
2014年 | 11篇 |
2013年 | 43篇 |
2012年 | 30篇 |
2011年 | 41篇 |
2010年 | 25篇 |
2009年 | 19篇 |
2008年 | 28篇 |
2007年 | 24篇 |
2006年 | 25篇 |
2005年 | 21篇 |
2004年 | 20篇 |
2003年 | 18篇 |
2002年 | 11篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 5篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有498条查询结果,搜索用时 31 毫秒
81.
Structural Chemistry - The current work is focused on in silico modeling of COX-1 inhibitors with enhanced safety gastric profile. A 5-point pharmacophore model, atom-based 3D quantitative... 相似文献
82.
Cholesterol addition and removal in pacific oyster oocytes does not improve cryopreservation success
The optimal cholesterol content in cells could provide the benefit of lowering or eliminating the lipid phase transition temperature, while maintaining membrane fluidity and strength; thus, making cells less sensitive to chilling injury and more amenable to cryopreservation. Such effects were shown in some gametes and embryos of certain mammalian species, however, some other cell types, benefited from cholesterol removal. The experiments developed in this study aimed to determine the effect of incubating Pacific oyster (Crassostrea gigas) oocytes in cholesterol-addition or removal solutions prior to cryopreservation on their post-thaw fertilization ability. The results showed a positive association of cholesterol with the oocytes when assessed by fluorescent microscopy. However, this uptake was not reflected by an increase in cholesterol as determined by colorimetric analysis or in the post-thaw fertilization rate of treated oocytes. It is presumed either that oyster oocytes already contain a substantial amount of cholesterol or other lipids in their plasma membranes and do not benefit from any additional cholesterol or there is no lipid phase transition temperature in oyster oocytes. 相似文献
83.
Hernández-Monje Diana Giraldo Liliana Moreno-Piraján Juan Carlos 《Journal of Thermal Analysis and Calorimetry》2020,142(4):1511-1522
Journal of Thermal Analysis and Calorimetry - Immersion enthalpies of activated carbons modified on their chemical surface were determined in benzene, cyclohexane, hexane, ethanol and water. Three... 相似文献
84.
85.
86.
Slezak Radoslaw Krzystek Liliana Ledakowicz Stanislaw 《Journal of Thermal Analysis and Calorimetry》2020,140(5):2337-2345
Journal of Thermal Analysis and Calorimetry - Gasification of the char obtained from the spent substrate after mushroom cultivation was carried out in a thermobalance connected to a mass... 相似文献
87.
88.
Manuel Sánchez-Cantú Liliana Ortiz-Moreno María E. Ramos-Cassellis Marco Marín-Castro C. De la Cerna-Hernández 《Applied biochemistry and biotechnology》2018,185(2):434-449
In this work, the enzymatic cocktail produced by Pleurotus djamor fungi extracted at pH of 4.8 and 5.3 was employed for castor cake solid-state treatment. Proximal, X-ray powder diffraction and scanning electron microscopy analysis of the pristine castor cake were carried out. First, Pleurotus djamor stain was inoculated in castor cake for the enzymatic production and the enzymatic activity was determined. The maximum enzymatic activity was identified at days 14 (65.9 UI/gss) and 11 (140.3 UI/gss) for the enzymatic cocktail obtained at pH 5.3 and 4.8, respectively. Then, the enzymatic cocktail obtained at the highest enzymatic activity days was employed directly over castor cake. Lignin was degraded throughout incubation time achieving a 47 and 45% decrease for the cocktail produced at pH 4.8 and 5.3, correspondingly. These results were corroborated by the SEM and XRD analysis where a higher porosity and xylan degradation were perceived throughout the enzymatic treatment. 相似文献
89.
Triflic acid-catalyzed highly stereoselective friedel-crafts aminoalkylation of indoles and pyrroles
A simple and efficient synthesis to both enantiomers of highly enantiomerically enriched alpha-trifluoromethyl-alpha-(heteroaryl)-glycine derivatives via highly stereoselective aminoalkylation of indoles and pyrroles is described. The triflic acid-catalyzed reaction of enantiomeric 3,3,3-trifluoro-pyruvate-alpha-methylbenzyl imines with indoles and pyrroles and the subsequent Pd-catalyzed hydrogenolysis of the methylbenzyl group provided the products in high yields and excellent enantioselectivities. 相似文献
90.
Palazón J Navarro-Ocaña A Hernandez-Vazquez L Mirjalili MH 《Molecules (Basel, Switzerland)》2008,13(8):1722-1742
Scopolamine is an alkaloid widely used in medicine for its anticholinergic activity. The aim of this review is to show that metabolic engineering techniques constitute a suitable tool to improve the production of tropane alkaloids, focusing in particular on scopolamine. We present an overview of results obtained by various research groups, including our own, who have studied the overexpression of genes involved in the biosynthesis of scopolamine in different plant species that produce tropane alkaloids. Experiments carried out to improve production in hairy root cultures will also be described, as well as those attempting to biotransform hyoscyamine into scopolamine in roots and transgenic tobacco cells. 相似文献