全文获取类型
收费全文 | 672篇 |
免费 | 32篇 |
专业分类
704篇 |
出版年
2024年 | 3篇 |
2023年 | 1篇 |
2022年 | 9篇 |
2021年 | 19篇 |
2020年 | 14篇 |
2019年 | 10篇 |
2018年 | 14篇 |
2017年 | 12篇 |
2016年 | 18篇 |
2015年 | 31篇 |
2014年 | 49篇 |
2013年 | 36篇 |
2012年 | 56篇 |
2011年 | 57篇 |
2010年 | 34篇 |
2009年 | 31篇 |
2008年 | 50篇 |
2007年 | 38篇 |
2006年 | 29篇 |
2005年 | 24篇 |
2004年 | 24篇 |
2003年 | 25篇 |
2002年 | 19篇 |
2001年 | 17篇 |
2000年 | 18篇 |
1999年 | 15篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1973年 | 4篇 |
1972年 | 7篇 |
1971年 | 4篇 |
1970年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有704条查询结果,搜索用时 15 毫秒
81.
82.
Human embryonic stem (hES) cells have unique features including unlimited growth capacity, expression of specific markers, normal karyotypes and an ability to differentiate. Many investigators have tried to use hES cells for cell-based therapy, but there is little information about the properties of available hES cell lines. We compared the characteristics of three hES cell lines. The expression of SSEA-1, -3, -4, and APase, was examined by immunocytochemistry, and Oct-4 expression was analyzed by RT-PCR. Differentiation of the hES cells in vitro and in vivo led to the formation of embryoid bodies (EBs) or teratomas. We examined the expression of tissue-specific markers in the differentiated cells by semiquantitative RT-PCR, and the ability of each hES cell line to proliferate was measured by flow cytometry of DNA content and ELISA. The three hES cell lines were similar in morphology, marker expression, and teratoma formation. However there were significant differences (P < 0.05) between the differentiated cells formed by the different cell lines in levels of expression of tissue-specific markers such as renin, kallikrein, Glut-2, beta- and delta-globin, albumin, and alpha1-antitrypsin (alpha1-AT). The hES cell lines also differed in proliferative activity. Our observations should be useful in basic and clinical hES cell research. 相似文献
83.
84.
A novel Gram-positive, aerobic, motile, hemolytic, endospore-forming and rod-shaped bacterium TW25T was isolated from a dead ark clam during a mass mortality event on the South coast of Korea. The strain grew optimally at
30°C, at pH 8–9, and with 1% (w/v) NaCl. The 16S rRNA gene sequence analysis indicated that strain TW25T was associated with the genus Ornithinibacillus and that it was most closely related to the type strain of Ornithinibacillus californiensis (98.5% similarity). The dominant cellular fatty acids were iso-C15:0, anteiso-C15:0 and C16:0. The peptidoglycan amino acid
type was A4β, containing l-ornithine and d-aspartic acid. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, four unidentified phospholipids, two unidentified
aminolipids and two unidentified lipids. The major respiratory quinone was menaquinone-7 (MK-7). The G + C content of genomic
DNA was 36.7 mol%. DNA–DNA hybridization experiments with related strains revealed lower than 11 ± 3% relatedness. Based on
this polyphasic taxonomic study, strain TW25T represents a novel species in the genus Ornithinibacillus, for which the name Ornithinibacillus scapharcae sp. nov. is proposed. The type strain is TW25T (=KACC 15116T = JCM 17314T). 相似文献
85.
86.
87.
88.
Yeon Ho Je Jin Hee Chang Mi Hyang Kim Jong Yul Roh Byung Rae Jin David R. O''''Reilly 《Biotechnology letters》2001,23(21):1809-1817
A system is described for the rapid generation of Bombyx mori nucleopolyhedrovirus (BmNPV)-based expression vectors. A series of novel BmNPV genomes, that include a mini-F replicon and therefore can be maintained in Escherichia coli, have been generated. These genomes lack a portion of the essential ORF1629 gene and cannot replicate independently in insect cells. However, they can be used as parental genomes for the generation of expression vectors by cotransfection with a transfer plasmid that includes an intact ORF1629. Only recombinant viruses that have acquired the ORF1629 gene from the transfer vector, and have therefore also acquired the foreign gene of interest, can replicate after cotransfection. Parental genomes with and without a polyhedrin gene are described, enabling the generation of occlusion-positive and occlusion-negative recombinant viruses. Occlusion-positive expression vectors enable the oral infection of B. mori larvae and can therefore be used for the mass production of a foreign protein in infected insects. 相似文献
89.
Joomin Lee Haeun Song Kangsan Roh Sungrae Cho Sukchan Lee Chang‐Hwan Yeom Seyeon Park 《Cell biochemistry and function》2016,34(5):317-325
The lymphatic vascular system plays an important role in tissue fluid homeostasis. Lymphedema is a chronic, progressive, and incurable condition that leads to lymphatic fluid retention; it may be primary (heritable) or secondary (acquired) in nature. Although there is a growing understanding of lymphedema, methods for the prevention and treatment of lymphedema are still limited. In this study, we investigated differential protein expressions in sham‐operated and lymphedema‐operated mice for 3 days, using two‐dimensional gel electrophoresis (2‐DE) and mass spectrometry analysis. Male improved methodology for culturing noninbred (ICR) mice developed lymphedema in the right hindlimb. Twenty functional proteins were found to be differentially expressed between lymphedema induced‐right leg tissue and normal left leg tissue. Out of these proteins, the protein levels of apolipoprotein A‐1 preprotein, alpha‐actinin‐3, mCG21744, parkinson disease, serum amyloid P‐component precursor, annexin A8, mKIAA0098 protein, and fibrinogen beta chain precursor were differentially upregulated in the lymphedema mice compared with the sham‐operated group. Western blotting analysis was used to validate the proteomics results. Our results showing differential up‐regulation of serum amyloid P‐component precursor, parkinson disease, and apolipoprotein A‐1 preprotein in lymphedema model over sham‐operated model suggest important insights into pathophysiological target for lymphedema. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
90.