全文获取类型
收费全文 | 1590篇 |
免费 | 225篇 |
国内免费 | 2篇 |
出版年
2021年 | 24篇 |
2020年 | 22篇 |
2019年 | 18篇 |
2018年 | 35篇 |
2017年 | 21篇 |
2016年 | 49篇 |
2015年 | 62篇 |
2014年 | 78篇 |
2013年 | 98篇 |
2012年 | 123篇 |
2011年 | 112篇 |
2010年 | 93篇 |
2009年 | 71篇 |
2008年 | 69篇 |
2007年 | 58篇 |
2006年 | 63篇 |
2005年 | 68篇 |
2004年 | 58篇 |
2003年 | 54篇 |
2002年 | 50篇 |
2001年 | 51篇 |
2000年 | 53篇 |
1999年 | 36篇 |
1998年 | 23篇 |
1997年 | 17篇 |
1996年 | 12篇 |
1995年 | 16篇 |
1994年 | 13篇 |
1993年 | 16篇 |
1992年 | 23篇 |
1991年 | 23篇 |
1990年 | 25篇 |
1989年 | 16篇 |
1988年 | 24篇 |
1987年 | 16篇 |
1986年 | 20篇 |
1985年 | 19篇 |
1984年 | 18篇 |
1983年 | 18篇 |
1982年 | 19篇 |
1980年 | 7篇 |
1979年 | 10篇 |
1978年 | 18篇 |
1977年 | 9篇 |
1976年 | 11篇 |
1974年 | 12篇 |
1973年 | 6篇 |
1972年 | 10篇 |
1971年 | 7篇 |
1969年 | 6篇 |
排序方式: 共有1817条查询结果,搜索用时 121 毫秒
51.
52.
53.
54.
55.
56.
57.
Oyundari Amartuvshin Chi‐Hung Lin Shao‐Chun Hsu Shih‐Han Kao Alvin Chen Wei‐Chun Tang Han‐Lin Chou Dong‐Lin Chang Yen‐Yang Hsu Bai‐Shiou Hsiao Elham Rastegari Kun‐Yang Lin Yu‐Ting Wang Chi‐Kuang Yao Guang‐Chao Chen Bi‐Chang Chen Hwei‐Jan Hsu 《Aging cell》2020,19(8)
Changes in mitochondrial dynamics (fusion and fission) are known to occur during stem cell differentiation; however, the role of this phenomenon in tissue aging remains unclear. Here, we report that mitochondrial dynamics are shifted toward fission during aging of Drosophila ovarian germline stem cells (GSCs), and this shift contributes to aging‐related GSC loss. We found that as GSCs age, mitochondrial fragmentation and expression of the mitochondrial fission regulator, Dynamin‐related protein (Drp1), are both increased, while mitochondrial membrane potential is reduced. Moreover, preventing mitochondrial fusion in GSCs results in highly fragmented depolarized mitochondria, decreased BMP stemness signaling, impaired fatty acid metabolism, and GSC loss. Conversely, forcing mitochondrial elongation promotes GSC attachment to the niche. Importantly, maintenance of aging GSCs can be enhanced by suppressing Drp1 expression to prevent mitochondrial fission or treating with rapamycin, which is known to promote autophagy via TOR inhibition. Overall, our results show that mitochondrial dynamics are altered during physiological aging, affecting stem cell homeostasis via coordinated changes in stemness signaling, niche contact, and cellular metabolism. Such effects may also be highly relevant to other stem cell types and aging‐induced tissue degeneration. 相似文献
58.
59.
Khanh B. Tran Gregory Gimenez Peter Tsai Sharada Kolekar Euan J. Rodger Aniruddha Chatterjee Anower Jabed Jen‐Hsing Shih Wayne R. Joseph Elaine S. Marshall Qian Wang Cristin G. Print Michael R. Eccles Bruce C. Baguley Peter R. Shepherd 《Pigment cell & melanoma research》2021,34(1):136-143
Melanoma is a disease associated with a very high mutation burden and thus the possibility of a diverse range of oncogenic mechanisms that allow it to evade therapeutic interventions and the immune system. Here, we describe the characterization of a panel of 102 cell lines from metastatic melanomas (the NZM lines), including using whole‐exome and RNA sequencing to analyse genetic variants and gene expression changes in a subset of this panel. Lines possessing all major melanoma genotypes were identified, and hierarchical clustering of gene expression profiles revealed four broad subgroups of cell lines. Immunogenotyping identified a range of HLA haplotypes as well as expression of neoantigens and cancer–testis antigens in the lines. Together, these characteristics make the NZM panel a valuable resource for cell‐based, immunological and xenograft studies to better understand the diversity of melanoma biology and the responses of melanoma to therapeutic interventions. 相似文献
60.
Yao-Ming Chang Chia-Lin Chang Wen-Hsiung Li Arthur Chun-Chieh Shih 《Molecular phylogenetics and evolution》2013,66(2):453-462
C4 plants evolved from C3 plants through a series of complex evolutionary steps. On the basis of the evolution of key C4 enzyme genes, the evolution of C4 photosynthesis has been considered a story of gene/genome duplications and subsequent modifications of gene function. If whole-genome duplication has contributed to the evolution of C4 photosynthesis, other genes should have been duplicated together with these C4 genes. However, which genes were co-duplicated with C4 genes and whether they have also played a role in C4 evolution are largely unknown. In this study, we developed a simple method to characterize the historical profile of the paralogs of a gene by tracing back to the most recent common ancestor (MRCA) of the gene and its paralog(s) and then counting the number of paralogs at each MRCA. We clustered the genes into clusters with similar duplication profiles and inferred their functional enrichments. Applying our method to maize, a familiar C4 plant, we identified many genes that show similar duplication profiles with those of the key C4 enzyme genes and found that the functional preferences of the C4 gene clusters are not only similar to those identified by an experimental approach in a recent study but also highly consistent with the functions required for the C4 photosynthesis evolutionary model proposed by S.F. Sage. Some of these genes might have co-evolved with the key C4 enzyme genes to increase the strength of C4 photosynthesis. Moreover, our results suggested that most key C4 enzyme genes had different origins and have undergone a long evolutionary process before the emergence of C4 grasses (Andropogoneae), consistent with the conclusion proposed by previous authors. 相似文献