全文获取类型
收费全文 | 386篇 |
免费 | 53篇 |
出版年
2018年 | 4篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 15篇 |
2013年 | 20篇 |
2012年 | 21篇 |
2011年 | 12篇 |
2010年 | 11篇 |
2009年 | 6篇 |
2008年 | 22篇 |
2007年 | 14篇 |
2006年 | 15篇 |
2005年 | 6篇 |
2004年 | 7篇 |
2003年 | 12篇 |
2002年 | 5篇 |
2001年 | 12篇 |
1999年 | 4篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 13篇 |
1991年 | 11篇 |
1990年 | 8篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 3篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1974年 | 3篇 |
1972年 | 3篇 |
1971年 | 5篇 |
1970年 | 3篇 |
1967年 | 3篇 |
1961年 | 3篇 |
1950年 | 3篇 |
1940年 | 4篇 |
1936年 | 18篇 |
1933年 | 13篇 |
1932年 | 8篇 |
1931年 | 11篇 |
1929年 | 4篇 |
排序方式: 共有439条查询结果,搜索用时 31 毫秒
431.
432.
433.
Prema Robinson Armandina Garza Joel Weinstock Jose A. Serpa Jerry Clay Goodman Kristian T. Eckols Bahrom Firozgary David J. Tweardy 《PLoS pathogens》2012,8(2)
Neurocysticercosis (NCC), a helminth infection of the brain, is a major cause of seizures. The mediators responsible for seizures in NCC are unknown, and their management remains controversial. Substance P (SP) is a neuropeptide produced by neurons, endothelial cells and immunocytes. The current studies examined the hypothesis that SP mediates seizures in NCC. We demonstrated by immunostaining that 5 of 5 brain biopsies from NCC patients contained substance P (SP)-positive (+) cells adjacent to but not distant from degenerating worms; no SP+ cells were detected in uninfected brains. In a rodent model of NCC, seizures were induced after intrahippocampal injection of SP alone or after injection of extracts of cysticercosis granuloma obtained from infected wild type (WT), but not from infected SP precursor-deficient mice. Seizure activity correlated with SP levels within WT granuloma extracts and was prevented by intrahippocampal pre-injection of SP receptor antagonist. Furthermore, extracts of granulomas from WT mice caused seizures when injected into the hippocampus of WT mice, but not when injected into SP receptor (NK1R) deficient mice. These findings indicate that SP causes seizures in NCC, and, suggests that seizures in NCC in humans may be prevented and/or treated with SP-receptor antagonists. 相似文献
434.
In democratic theory, “legitimacy” refers to the set of conditions that must be in place in order for the claims to authority of somebody to be deemed appropriate, and for their claims to compliance to be warranted. Though criteria of legitimacy have been elaborated in the context of democratic states, there is no reason for them not to be drawn up, with appropriate amendments, for other kinds of authority structures. This paper examines the claims to authority made over researchers by international bodies governing research ethics, who exercise their authority by the research ethics guidelines they produce (including recent revisions to the Declaration of Helsinki and CIOMS Guidelines). We argue that discussions of such bodies and sets of guidelines often elide questions of justification and questions of legitimacy, and that the grounds that might allow us to mount a strong case for the latter are at present sorely underdeveloped. 相似文献
435.
436.
THE EVOLUTION AND ANATOMY OF THE CEREBELLUM 总被引:2,自引:0,他引:2
437.
This review summarizes the evidence suggesting a role for second messengers in the thymus dependent differentiation of lymphocytes. Special emphasis will be placed on the potential for such studies to indicate differences and similarities not only between thymosin and other thumus factors but between the various peptides which are present in thymosin fraction 5. 相似文献
438.
A M Blum A Metwali C Crawford J Li K Qadir D E Elliott J V Weinstock 《FASEB journal》2001,15(6):950-957
Substance P (SP) regulates interferon-gamma (IFN-gamma) production through interaction with the SP receptor NK1 (SPr) on T cells at sites of inflammation. Using murine schistosomiasis, we evaluated whether SPr expression was subject to immunoregulation. Splenocytes from schistosome-infected mice cultured for < or =18 h did not express SPr, as determined by quantitative polymerase chain reaction assay. However, exposure to schistosome egg antigen (SEA) for < or =4 h induced strong receptor expression. Experiments using splenocytes fractionated with antibody-coupled, paramagnetic beads showed that induction localized exclusively to T cells. Receptor protein expression was confirmed with Western blot. Interleukin 12 (IL-12) also induced strong T-cell SPr expression. Both SEA and IL-12 remained strong inducers of T-cell SPr in lymphocytes from the IL-12 (p40) and IFN-gamma R double-knockout mouse, which suggested that SEA did not require IL-12 to induce SPr and that both worked independently of IFN-gamma. Splenocytes from wild-type mice cultured with SEA and neutralizing anti-IL-12 monoclonal antibody (mAb) also showed SPr induction. However, anti-Ia mAb inhibited SEA induction of SPR: Thus, SPr is inducible on T cells. SEA induces SPr through interaction with T-cell receptor (TCR), independently of IL-12 and IFN-gamma. IL-12 induces SPr independently of TCR activation and IFN-gamma expression. SP and its receptor, which regulate IFN-gamma production, are probably part of the IL-12-Th1 circuit. 相似文献
439.