全文获取类型
收费全文 | 44798篇 |
免费 | 18147篇 |
国内免费 | 58篇 |
专业分类
化学 | 56806篇 |
晶体学 | 51篇 |
力学 | 2055篇 |
数学 | 2853篇 |
物理学 | 1238篇 |
出版年
2024年 | 157篇 |
2023年 | 4081篇 |
2022年 | 1500篇 |
2021年 | 2586篇 |
2020年 | 4662篇 |
2019年 | 2360篇 |
2018年 | 2313篇 |
2017年 | 632篇 |
2016年 | 5643篇 |
2015年 | 5567篇 |
2014年 | 5019篇 |
2013年 | 5238篇 |
2012年 | 3312篇 |
2011年 | 1217篇 |
2010年 | 3496篇 |
2009年 | 3446篇 |
2008年 | 1180篇 |
2007年 | 886篇 |
2006年 | 230篇 |
2005年 | 190篇 |
2004年 | 141篇 |
2003年 | 118篇 |
2002年 | 93篇 |
1997年 | 91篇 |
1996年 | 91篇 |
1995年 | 151篇 |
1993年 | 213篇 |
1992年 | 98篇 |
1988年 | 116篇 |
1987年 | 99篇 |
1985年 | 104篇 |
1984年 | 110篇 |
1983年 | 111篇 |
1982年 | 129篇 |
1981年 | 157篇 |
1980年 | 195篇 |
1979年 | 187篇 |
1978年 | 192篇 |
1977年 | 311篇 |
1976年 | 361篇 |
1975年 | 456篇 |
1974年 | 472篇 |
1973年 | 284篇 |
1972年 | 371篇 |
1971年 | 355篇 |
1970年 | 542篇 |
1969年 | 413篇 |
1968年 | 456篇 |
1967年 | 114篇 |
1963年 | 112篇 |
排序方式: 共有10000条查询结果,搜索用时 866 毫秒
991.
In this contribution, we present two new united‐atom force fields (UA‐FFs) for 1‐alkyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide [CnMIM][NTf2] (n=1, 2, 4, 6, 8) ionic liquids (ILs). One is parametrized manually, and the other is developed with the gradient‐based optimization workflow (GROW). By doing so, we wanted to perform a hard test to determine how researchers could benefit from semiautomated optimization procedures. As with our already published all‐atom force field (AA‐FF) for [CnMIM][NTf2] (T. Köddermann, D. Paschek, R. Ludwig, ChemPhysChem 2007, 8, 2464 ), the new force fields were derived to fit experimental densities, self‐diffusion coefficients, and NMR rotational correlation times for the IL cation and for water molecules dissolved in [C2MIM][NTf2]. In the manual force field, the alkyl chains of the cation and the CF3 groups of the anion were treated as united atoms. In the GROW force field, only the alkyl chains of the cation were united. All other parts of the structures of the ions remained unchanged to prevent any loss of physical information. Structural, dynamic, and thermodynamic properties such as viscosity, cation rotational correlation times, and heats of vaporization calculated with the new force fields were compared with values simulated with the previous AA‐FF and the experimental data. All simulated properties were in excellent agreement with the experimental values. Altogether, the UA‐FFs are slightly superior for speed‐up reasons. The UA‐FF speeds up the simulation by about 100 % and reduces the demanded disk space by about 78 %. More importantly, real time and efforts to generate force fields could be significantly reduced by utilizing GROW. The real time for the GROW parametrization in this work was 2 months. Manual parametrization, in contrast, may take up to 12 months, and this is, therefore, a significant increase in speed, though it is difficult to estimate the duration of manual parametrization. 相似文献
992.
993.
994.
995.
996.
Dr. Sophie A.‐L. Thétiot‐Laurent Dr. Jérôme Boissier Dr. Anne Robert Prof. Dr. Bernard Meunier 《Angewandte Chemie (International ed. in English)》2013,52(31):7936-7956
After malaria, schistosomiasis (or bilharzia) is the second most prevalent disease in Africa, and is occurring in over 70 countries in tropical and subtropical regions. It is estimated that 600 million people are at risk of infection, 200 million people are infected, and at least 200 000 deaths per year are associated with the disease. All schistosome species are transmitted through contact with fresh water that is infested with free‐swimming forms of the parasite, which is known as cercariae and produced by snails. When located in the blood vessels of the host, larval and adult schistosomes digest red cells to acquire amino acids for growth and development. Vaccine candidates have been unsuccessful up to now. Against such devastating parasitic disease, the antischistosomal arsenal is currently limited to a single drug, praziquantel, which has been used for more than 35 years. Because the question of the reduction of the activity of praziquantel was raised recently, it is thus urgent to create new and safe antischistosomal drugs that should be combined with praziquantel to develop efficient bitherapies. 相似文献
997.
998.
999.
Dr. Stefanie Neubauer Dr. Florian Rechenmacher Dr. Ambros J. Beer Dr. Flavio Curnis Karolin Pohle Dr. Calogero D'Alessandria Prof. Dr. Hans‐Jürgen Wester Prof. Dr. Ute Reuning Prof. Dr. Angelo Corti Prof. Dr. Markus Schwaiger Prof. Dr. Horst Kessler 《Angewandte Chemie (International ed. in English)》2013,52(44):11666-11666
1000.