全文获取类型
收费全文 | 779篇 |
免费 | 53篇 |
出版年
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 7篇 |
2019年 | 12篇 |
2018年 | 13篇 |
2017年 | 13篇 |
2016年 | 13篇 |
2015年 | 30篇 |
2014年 | 35篇 |
2013年 | 33篇 |
2012年 | 46篇 |
2011年 | 35篇 |
2010年 | 24篇 |
2009年 | 18篇 |
2008年 | 29篇 |
2007年 | 22篇 |
2006年 | 20篇 |
2005年 | 27篇 |
2004年 | 21篇 |
2003年 | 26篇 |
2002年 | 45篇 |
1999年 | 10篇 |
1998年 | 6篇 |
1997年 | 10篇 |
1996年 | 11篇 |
1995年 | 9篇 |
1994年 | 7篇 |
1993年 | 13篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1990年 | 17篇 |
1989年 | 7篇 |
1988年 | 11篇 |
1987年 | 21篇 |
1986年 | 12篇 |
1985年 | 7篇 |
1984年 | 15篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 14篇 |
1980年 | 7篇 |
1979年 | 10篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1974年 | 5篇 |
1907年 | 8篇 |
1906年 | 4篇 |
1905年 | 8篇 |
1904年 | 6篇 |
排序方式: 共有832条查询结果,搜索用时 875 毫秒
821.
Embryonic lethal mutation in mouse collagen I gene causes rupture of blood vessels and is associated with erythropoietic and mesenchymal cell death 总被引:26,自引:0,他引:26
The role of collagen I for midgestation development was studied in homozygous Mov 13 embryos, which cannot synthesize alpha 1(1) mRNA as a result of insertional mutagenesis and most of which die between day 12 and 14 of gestation. No type I collagen was detected in mutant embryos, while the distribution of other collagens, laminin, and fibronectin was not affected. Mutant embryos develop normally up to day 12 of gestation, suggesting that collagen I has no essential role in the early phase of morphogenesis. The first pathological events were detected in hemopoietic cells of the liver, followed by necroses of mesenchymal cells in other parts of the embryo. The sudden death is caused by the rupture of a major blood vessel, indicating an important role for collagen I in establishing the mechanical stability of the circulatory system. Our results furthermore suggest that complex cell interactions in embryonic development such as those in early hemopoiesis may depend on the presence of collagen type I. 相似文献
822.
823.
Rupert C. Marshall David E. Whitworth 《BioEssays : news and reviews in molecular, cellular and developmental biology》2019,41(4)
For decades, myxobacteria have been spotlighted as exemplars of social “wolf‐pack” predation, communally secreting antimicrobial substances into the shared public milieu. This behavior has been described as cooperative, becoming more efficient if performed by more cells. However, laboratory evidence for cooperativity is limited and of little relevance to predation in a natural setting. In contrast, there is accumulating evidence for predatory mechanisms promoting “selfish” behavior during predation, which together with conflicting definitions of cooperativity, casts doubt on whether microbial “wolf‐pack” predation really is cooperative. Here, it is hypothesized that public‐goods‐mediated predation is not cooperative, and it is argued that a holistic model of microbial predation is needed, accounting for predator and prey relatedness, social phenotypes, spatial organization, activity/specificity/transport of secreted toxins, and prey resistance mechanisms. Filling such gaps in our knowledge is vital if the evolutionary benefits of potentially costly microbial behaviors mediated by public goods are to be properly understood. 相似文献
824.
825.
Rupert Huter 《Plant Systematics and Evolution》1906,56(7):284-287
Ohne Zusammenfassung 相似文献
826.
Nucleolus organizer regions (NOR) are actively expressed on both sets of parental chromosomes in mouse-Chines hamster hybrid cells retaining 85–95% of each parental complement. A hamster NOR, which is active in primary fetal hamster cells, but suppressed in the established AK412 line, is reactivated in these hybrids, demonstrating control of NOR expression. 相似文献
827.
Rupert Huter 《Plant Systematics and Evolution》1904,54(12):448-457
Ohne Zusammenfassung 相似文献
828.
829.
830.