全文获取类型
收费全文 | 149篇 |
免费 | 18篇 |
出版年
2022年 | 2篇 |
2017年 | 2篇 |
2015年 | 7篇 |
2014年 | 5篇 |
2013年 | 5篇 |
2012年 | 3篇 |
2011年 | 2篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1994年 | 2篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 6篇 |
1986年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1969年 | 2篇 |
1968年 | 3篇 |
1967年 | 2篇 |
1964年 | 3篇 |
1963年 | 4篇 |
1962年 | 2篇 |
1956年 | 3篇 |
1955年 | 2篇 |
1937年 | 2篇 |
排序方式: 共有167条查询结果,搜索用时 140 毫秒
161.
Effect of hormonal and neuronal agents on adenylate cyclase from smooth muscle of the gastric antrum
Sonia Baur Bill Grant Roberta K. Spaulding 《Biochimica et Biophysica Acta (BBA)/General Subjects》1979,584(3):365-374
Smooth muscle adenylate cyclase of a membrane preparation of canine gastric antrum has been characterized, and the effect of hormonal and neuronal agents examined. The enzyme is active in the presence of Mg2+ or Mn2+, but is inhibited by Ca2+. The Km is 0.5 mM ATP, similar to the Km of skeletal muscle adenylate cyclase. The enzyme is activated by isoproterenol but not norepinephrine, consistent with a β2-catecholamine receptor-adenylate cyclase interaction. Secretin activates the enzyme in concentrations as low as 1 · 10?11 M, while glucagon was effective only at 1 · 10?6 M. Prostaglandin E1 and E2 have a biphasic effect with activation of adenylate cyclase at 1 · 10?5 M and a small but significant inhibition of enzyme activity at 1 · 10?11 M. 相似文献
162.
The production of antibodies to nucleic acids, and in particular to DNA, has been implicated in the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE). However, little is known about the conditions under which DNA is immunogenic, particularly in well-characterized in vitro systems. Therefore, we examined whether a source of cytokines, in conjunction with D-DNA, permitted a polyclonal or antigen-specific B-cell response. Spleen cells from MRL +/+ SLE-prone mice were incubated with supernatant from concanavalin A-stimulated spleen cells (Con A SN, a source of cytokines) and D-DNA. A potent antibody response developed to guanosine (GU) and D-DNA but not to fluorescein (FL), using as little as 10 ng D-DNA in conjunction with Con A SN. In order to further examine the cellular requirements for D-DNA to be immunogenic, populations of B cells which bound GU (an immunodominant epitope of DNA) or an irrelevant FL-binding population were purified and incubated with DNA and Con A SN. Interestingly, GU-binding, but not FL-binding B cells could be triggered by D-DNA derived from calf thymus, a result suggesting that DNA was not acting simply as a polyclonal B-cell activator. D-DNA optimally triggered GU+ B cells within a narrow dose range similar to many thymus-independent Type II antigens with repetitive determinants. If DNA were truly an autoantigen, then DNA derived from the MRL +/+ mouse should be capable of triggering GU-binding B cells. When this hypothesis was tested, D-DNA, but not N-DNA, functioned as a potent immunogen. These experiments document the ability of DNA to act as a specific immunogen and suggest that, under appropriate conditions, nucleic acid may induce autoantibody production in vivo. 相似文献
163.
164.
165.
166.
STUDIES ON THE STABILITY OF THE NORMAL HUMAN FECAL FLORA. 总被引:9,自引:0,他引:9
Zubrzycki, Leonard (Temple University, Philadelphia, Pa.) and Earle H. Spaulding. Studies on the stability of the normal human fecal flora. J. Bacteriol. 83:968-974. 1962.-The results of two series of stool cultures show that members of the genus Bacteriodes constitute the most numerous group of bacteria in the normal human adult fecal flora. Together with the enterococci, coliform bacilli, diphtheroids, and lactobacilli, these major components account for more than 99% of the total counts. Wide fluctuations in the number and types of minor organisms observed suggest the probability that they are held in check by these major components which may also possess mechanisms for preventing pathogens from establishing themselves in the large bowel. 相似文献
167.