首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   240篇
  免费   1篇
  国内免费   1篇
现状及发展   123篇
研究方法   31篇
综合类   88篇
  2018年   3篇
  2016年   3篇
  2014年   1篇
  2013年   5篇
  2012年   5篇
  2011年   9篇
  2010年   1篇
  2008年   9篇
  2007年   3篇
  2006年   9篇
  2005年   12篇
  2004年   9篇
  2003年   4篇
  2002年   18篇
  2001年   5篇
  2000年   6篇
  1999年   2篇
  1998年   2篇
  1997年   1篇
  1996年   1篇
  1994年   3篇
  1993年   1篇
  1992年   4篇
  1990年   3篇
  1989年   6篇
  1988年   2篇
  1987年   4篇
  1986年   8篇
  1985年   9篇
  1984年   7篇
  1983年   7篇
  1982年   2篇
  1981年   6篇
  1980年   3篇
  1979年   8篇
  1978年   5篇
  1977年   4篇
  1976年   5篇
  1974年   3篇
  1973年   4篇
  1972年   2篇
  1971年   2篇
  1970年   6篇
  1969年   7篇
  1968年   5篇
  1967年   2篇
  1966年   8篇
  1965年   2篇
  1964年   4篇
  1956年   1篇
排序方式: 共有242条查询结果,搜索用时 171 毫秒
1.
Summary Porcine or human follicular fluid inhibited the spontaneous maturation of isolated hamster oocytes in vitro during the first 1.5 h of culture. Moreover, the presence of 50% follicular fluid combined with 100 M dbcAMP cooperatively reduced the incidence of germinal vesicle breakdown. The addition of FSH also inhibited the resumption of meiosis, and the presence of LH did not overcome the inhibitory effects of follicular fluid and tended to impede isolated hamster oocyte maturation in vitro.  相似文献   
2.
2-Carboxyethylgermanium sesquioxide (Ge-132), a synthesized organogermanium compound with immunomodulaing activities, was shown to be an inducer of anti-suppressor T cells in normal mice. The suppressor cell activity of T6S cells, a clone of burn-induced CD8+ IL-4-producing suppressor T cells, was clearly inhibited when a mixed lymphocyte-tumor cell reaction of the clone was conducted with splenic mononuclear cells from mice treated orally with a 100 mg/kg dose of Ge-132. The activity of anti-suppressor cells was demonstrated in spleens of mice 2 days after treatment with Ge-132 and reached its peak on day 3. The anti-suppressor cells induced by the compound were of a contrasuppressor T cell-linage, because they were characterized as CD4+ CD28+ TCR/+ Vicia villosa lectin-adherent T cells. These cells produced IFN- but did not produce IL-2, IL-4, IL-6 or IL-10 in their culture fluids. CD4+ anti-suppressor T cells induced by Ge-132 may be different from other subsets of CD4+ T cells because Th1 and Th2 cells generated in our laboratory did not adhere toVicia villosa lectin-coated petri dishes, and each produced specific cytokines. Th1 cells produced IFN- and IL-2 while Th2 cells produce IL-4 and IL-10 in vitro. These results suggest that Ge-132 may be useful as an inducer of contrasuppressor T cells in immunocompromised individuals bearing suppressor T cells. To eliminate suppressor T cells from immunocompromised hosts may result in improved resistance from various opportunistic infections.  相似文献   
3.
Summary DNA-containing areas in various phages (T4, , T7 and 29) could be observed at the light microscopic level using ethidium bromide epi-fluorescent microscopy. The fluorescent intensity per phage was in linear proportion to the DNA content in each phage.Acknowledgements. This work was supported in part by the grant No. 521708 and No. 511212 from the Japan Ministry of Education, Science and Culture.  相似文献   
4.
Summary The substrate- and inhibitor-related characteristics of monoamine oxidase (MAO) were studied on chick brain mitochondria. It was found that neither 5-hydroxytryptamine nor -phenylethylamine is the specific substrate for type A and type B MAO in chick brain.  相似文献   
5.
Semaphorins are axon guidance factors that assist growing axons in finding appropriate targets and forming synapses. Emerging evidence suggests that semaphorins are involved not only in embryonic development but also in immune responses. Semaphorin 7A (Sema7A; also known as CD108), which is a glycosylphosphatidylinositol-anchored semaphorin, promotes axon outgrowth through beta1-integrin receptors and contributes to the formation of the lateral olfactory tract. Although Sema7A has been shown to stimulate human monocytes, its function as a negative regulator of T-cell responses has also been reported. Thus, the precise function of Sema7A in the immune system remains unclear. Here we show that Sema7A, which is expressed on activated T cells, stimulates cytokine production in monocytes and macrophages through alpha1beta1 integrin (also known as very late antigen-1) as a component of the immunological synapse, and is critical for the effector phase of the inflammatory immune response. Sema7A-deficient (Sema7a-/-) mice are defective in cell-mediated immune responses such as contact hypersensitivity and experimental autoimmune encephalomyelitis. Although antigen-specific and cytokine-producing effector T cells can develop and migrate into antigen-challenged sites in Sema7a-/- mice, Sema7a-/- T cells fail to induce contact hypersensitivity even when directly injected into the antigen-challenged sites. Thus, the interaction between Sema7A and alpha1beta1 integrin is crucial at the site of inflammation. These findings not only identify a function of Sema7A as an effector molecule in T-cell-mediated inflammation, but also reveal a mechanism of integrin-mediated immune regulation.  相似文献   
6.
The scale-free and small-world properties are studied in detail for the complex earthquake networks constructed from the seismic data sets taken from California (USA), Japan, Iran and Chile. It is found that, in all these geographical regions, both the exponent / of the power-law connectivity distribution and the clustering coefficient C take the universal invariant values /≈1 and C≈0.85, respectively, as the cell size, which is the scale of coarse graining needed for construction of network, becomes larger than a certain value. A possible physical interpretation is given to the emergence of such remarkable invariance.  相似文献   
7.
Genetic mapping with SNP markers in Drosophila.   总被引:10,自引:0,他引:10  
Map-based positional cloning of Drosophila melanogaster genes is hampered by both the time-consuming, error-prone nature of traditional methods for genetic mapping and the difficulties in aligning the genetic and cytological maps with the genome sequence. The identification of sequence polymorphisms in the Drosophila genome will make it possible to map mutations directly to the genome sequence with high accuracy and resolution. Here we report the identification of 7,223 single-nucleotide polymorphisms (SNPs) and 1,392 insertions/deletions (InDels) in common laboratory strains of Drosophila. These sequence polymorphisms define a map of 787 autosomal marker loci with a resolution of 114 kb. We have established PCR product-length polymorphism (PLP) or restriction fragment-length polymorphism (RFLP) assays for 215 of these markers. We demonstrate the use of this map by delimiting two mutations to intervals of 169 kb and 307 kb, respectively. Using a local high-density SNP map, we also mapped a third mutation to a resolution of approximately 2 kb, sufficient to localize the mutation within a single gene. These methods should accelerate the rate of positional cloning in Drosophila.  相似文献   
8.
The antiviral activity of Shigyaku-to (TJS-109), a traditional Chinese herbal medicine, was investigated in mice infected with herpes simplex virus type 1 (HSV-1). TJS-109 is a combination of the medicinal plant extracts fromZingiberis siccatum rhizoma,Aconiti tuber andGlycyrrhizae radix in a specific proportion. Mice infected with a 10 LD50 dose of HSV-1 were treated with TJS-109 orally at doses of 1.25 to 20 mg/kg 2 days before, and 1 and 4 days after the infection. The treated groups had 80% (1.25 mg/kg), 40% (5 mg/kg) and 23% (20 mg/kg) mortality rates 25 days after the infection as compared with a 100% mortality rate in control mice treated with saline. When HSV-1 infected mice (recipients) received CD8+T cell fractions derived from spleens of mice treated with TJS-109 (donors), 70% of recipients survived, as compared with 0% survivors in the groups of mice treated with saline, B cell fractions, CD4+ T cell fractions or macrophage-enriched fractions prepared from the same donors. TJS-109 did not show any virucidal activities against HSV-1 or any virostatic activities on the growth of HSV-1 in Vero cells. These results suggest that TJS-109 protected mice exposed to lethal amounts of HSV-1 through the activation of CD8+ T cells.  相似文献   
9.
10.
Determination of polyamine oxidase activities in human tissues   总被引:2,自引:0,他引:2  
A very simple fluorometric assay for polyamine oxidase (PAO) in tissues, with N1-monoacetylspermine as substrate, is described. The PAO was present in all human organs tested; it was highest in the liver, followed by the testis, kidney, spleen and small intestine.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号