全文获取类型
收费全文 | 123篇 |
免费 | 14篇 |
专业分类
137篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 6篇 |
2013年 | 9篇 |
2012年 | 8篇 |
2011年 | 3篇 |
2010年 | 4篇 |
2009年 | 3篇 |
2008年 | 6篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2004年 | 5篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 6篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1975年 | 1篇 |
1973年 | 5篇 |
1972年 | 4篇 |
1971年 | 2篇 |
1970年 | 4篇 |
1969年 | 2篇 |
1968年 | 3篇 |
1967年 | 5篇 |
1966年 | 5篇 |
1953年 | 1篇 |
排序方式: 共有137条查询结果,搜索用时 0 毫秒
131.
The cellular response to an intraperitoneal injection of antigen (tetanus toxoid) was studied in reconstituted animals in order to determine the mechanism of control of eosinophil granulocytopoiesis. Antigen treatment of the marrow cell donors did not consistently increase the number of spleen and bone marrow colonies in recipient animals or change the percentage of eosinophil or other hemopoietic colony types. Antigen pre-treatment of the irradiated recipients increased the percentage of eosinophil-containing colonies in the spleen and femoral bone marrow without significantly changing the total number of either spleen or marrow colonies. Antigen treatment of both the bone marrow cell donor and recipient produced a further increase in the percentage of eosinophil-containing colonies in the marrow cavity, but not in the spleen. Antigen treatment of the irradiated recipient increased the number of eosinophilic cells (but not the total number of cells) in both the peritoneal cavity and the bone marrow. Antigen treatment of both the marrow donor and recipient produced a further increase in the number of eosinophilic cells in the peritoneal cavity, but not in a single femur. Since antigen treatment of the marrow recipient, or recipient and donor, but not of the marrow donor alone, results in increased eosinophilic cell and colony numbers, the effect of antigen appears to be mediated through some host factor(s), perhaps the eosinophilic hemopoietic inducing microenvironment (HIM), rather than directly on the hemopoietic stem cells. 相似文献
132.
133.
134.
135.
Presence of retrovirus in the B95-8 Epstein-Barr virus-producing cell line from different sources 总被引:1,自引:0,他引:1
Joseph J. Tumilowicz Gary E. Gallick James L. East Sen Pathak John J. Trentin Ralph B. Arlinghaus 《In vitro cellular & developmental biology. Plant》1984,20(6):486-492
Summary The B95-8 cell line, a widely used source of highly transforming Epstein-Barr virus (EBV), obtained from the laboratory of
origin, harbored an infectious retrovirus. This retrovirus generally resembled the Type D retroviruses structurally and developmentally
and like the Type D retroviruses preferred Mg2+ to Mn2+ in its RNA-directed DNA polymerase reaction. Evidence for the presence of retrovirus was found in B95-8 cultures from two
other sources within the United States, either by assay for polymerase or by electron microscopy. Comparison of two B95-8
cell lines showed cytogenetic differences as well as differences in retroviral activities. The results suggest that any B95-8
culture should be tested for the presence of retrovirus before its use as a source of EBV.
This research was supported through the National Research and Demonstration Center (HL-17269-07) awarded to Baylor College
of Medicine by the National Heart, Lung, and Blood Institute, Bethesda, MD, by RD-125 from the American Cancer Society, by
K06 CA14219, CA16781, CA25465, and CA16672 from the National Cancer Institute, Bethesda, MD, and by G-429 from the Robert
A. Welch Foundation. G. E. G. was supported by Public Health Service training Grant CA-09299. 相似文献
136.
Ricardo Castilho Garcez Bianca Luise Teixeira Suelen dos Santos Schmitt Márcio Alvarez-Silva Andréa Gonçalves Trentin 《Cellular and molecular neurobiology》2009,29(8):1087-1091
Proliferation of neural crest (NC) stem cells and their subsequent differentiation into different neural cell types are key
early events in the development of the peripheral nervous system. Soluble growth factors present at the sites where NC cells
migrate are critical to the development of NC derivatives in each part of the body. In the present study, we further investigate
the effect of microenvironmental factors on quail trunk NC development. We show for the first time that EGF induces differentiation
of NC to the neuronal and melanocytic phenotypes, while fibroblast growth factor 2 (FGF2) promotes NC differentiation to Schwann
cells. In the presence of both EGF and FGF2, the neuronal differentiation predominates. Our results suggest that FGF2 stimulates
gliogenesis, while EGF promotes melanogenesis and neurogenesis. The combination of both growth factors stimulates neurogenesis.
These findings suggest that these two growth factors may play an important role in the fate decision of NC progenitors and
in the development of the peripheral nervous system. 相似文献
137.
Industrial biotechnology employs the controlled use of microorganisms for the production of synthetic chemicals or simple
biomass that can further be used in a diverse array of applications that span the pharmaceutical, chemical and nutraceutical
industries. Recent advances in metagenomics and in the incorporation of entire biosynthetic pathways into Saccharomyces cerevisiae have greatly expanded both the fitness and the repertoire of biochemicals that can be synthesized from this popular microorganism.
Further, the availability of the S. cerevisiae entire genome sequence allows the application of systems biology approaches for improving its enormous biosynthetic potential.
In this review, we will describe some of the efforts on using S. cerevisiae as a cell factory for the biosynthesis of high-value natural products that belong to the families of isoprenoids, flavonoids
and long chain polyunsaturated fatty acids. As natural products are increasingly becoming the center of attention of the pharmaceutical
and nutraceutical industries, the use of S. cerevisiae for their production is only expected to expand in the future, further allowing the biosynthesis of novel molecular structures
with unique properties. 相似文献