全文获取类型
收费全文 | 2310篇 |
免费 | 84篇 |
专业分类
2394篇 |
出版年
2023年 | 7篇 |
2022年 | 12篇 |
2021年 | 18篇 |
2020年 | 20篇 |
2019年 | 28篇 |
2018年 | 51篇 |
2017年 | 56篇 |
2016年 | 61篇 |
2015年 | 70篇 |
2014年 | 108篇 |
2013年 | 121篇 |
2012年 | 146篇 |
2011年 | 182篇 |
2010年 | 105篇 |
2009年 | 69篇 |
2008年 | 139篇 |
2007年 | 149篇 |
2006年 | 169篇 |
2005年 | 106篇 |
2004年 | 115篇 |
2003年 | 123篇 |
2002年 | 115篇 |
2001年 | 60篇 |
2000年 | 67篇 |
1999年 | 37篇 |
1998年 | 17篇 |
1997年 | 10篇 |
1996年 | 9篇 |
1995年 | 10篇 |
1994年 | 7篇 |
1992年 | 6篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 16篇 |
1986年 | 13篇 |
1985年 | 16篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1980年 | 9篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 6篇 |
1974年 | 11篇 |
1973年 | 7篇 |
1972年 | 14篇 |
1971年 | 5篇 |
1970年 | 7篇 |
排序方式: 共有2394条查询结果,搜索用时 0 毫秒
991.
Summary Blastomeres isolated from two-cell mouse embryos were cultured until they started to cleave. When the cleavage furrow developed they were subjected to cytochalasin B (CB) and were studied with the electron microscope. The initial response to CB is that the furrow is more folded and microvillous than in the control. Later the blastomeres round up. The protrusions covered with abundant long microvilli are found scattered within their equatorial surface. Extraction with glycerol solution before fixation permits visualization of condensations of felt-like filamentous material in contact with the cleavage furrow during the initial response to CB and in the protrusions of rounded cells. We consider clumping of filaments in surface protrusions to be a specific response to CB treatment of the contractile ring.Some of the previous papers by this author have been published under the name Opas 相似文献
992.
For establishing normal mean values of the parameters of the electrocardiographic curve and their standard deviations 50 male guinea pigs were studied. The directions of temporary vectors of atrial (AP) and ventricular (AQRS) depolarization times, and ventricular repolarization time (AT) were determined, and the position of the heart was evaluated. In all animals limb leads I, II, III, aVR, aVL, aVF were used, and in 38 animals additionally the precordial leads V1, V2, V3, V4, V5, V6 were applied. The investigations were done by a non-invasive method with a specially designed plate making possible immobilization of the animals in supine position under general anaesthesia with urethane. In 10% of the animals abnormalities were detected in the ECG curve and these guinea pigs were eliminated from further analysis. The investigations showed that, after consideration given to the differences in the ECG curves in relation to man, guinea pigs might be used for preclinical cardiological studies. 相似文献
993.
994.
995.
996.
Structure-activity relationship studies of protective function of nitroxides in Fenton system 总被引:1,自引:0,他引:1
Jolanta Glebska Lukasz Pulaski Krzysztof Gwozdzinski Janusz Skolimowski 《Biometals》2001,14(2):159-170
The aim of this study was to evaluate the effect of piperidine nitroxides and their amine precursors on deoxyribose oxidation in the Fenton system. Protecting activity of nitroxides was found to be concentration-dependent and strongly influenced by ring substituents, while secondary amines did not provide any protection. The reported results suggest a mechanism of nitroxide action through iron oxidation rather than through direct scavenging of hydroxyl radicals. Moreover, presented data point to the danger of interference of nitroxides during the TBARS assay procedure. 相似文献
997.
998.
In this study we discuss stacking interactions in cytosine dimer in conformations appearing in B-DNA crystals. The variational–perturbational scheme was applied for decomposition of the intermolecular interaction energy at the MP2 level of theory. The significant influence of the mutual orientation of cytosine monomers was observed not only on the total intermolecular interaction energy but also on its components: Different components of intermolecular interaction energy depend in different manner on parameters describing mutual orientation of cytosine monomers. 相似文献
999.
Sztanke Małgorzata Rzymowska Jolanta Sztanke Krzysztof 《Molecular and cellular biochemistry》2016,413(1-2):179-187
Molecular and Cellular Biochemistry - The study was aimed at describing the mode of action of an innovative drug-like congener of fused azaisocytosine—EIMTC (ethyl... 相似文献
1000.