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   344篇
  免费   11篇
  国内免费   24篇
丛书文集   10篇
教育与普及   5篇
理论与方法论   1篇
现状及发展   114篇
研究方法   1篇
综合类   248篇
  2023年   1篇
  2022年   2篇
  2021年   2篇
  2020年   2篇
  2019年   2篇
  2018年   5篇
  2017年   4篇
  2016年   6篇
  2015年   5篇
  2014年   5篇
  2013年   9篇
  2012年   7篇
  2011年   16篇
  2010年   5篇
  2009年   20篇
  2008年   19篇
  2007年   25篇
  2006年   28篇
  2005年   26篇
  2004年   24篇
  2003年   31篇
  2002年   14篇
  2001年   11篇
  2000年   7篇
  1999年   11篇
  1998年   12篇
  1997年   6篇
  1996年   14篇
  1995年   7篇
  1994年   5篇
  1993年   10篇
  1992年   8篇
  1991年   4篇
  1990年   6篇
  1989年   4篇
  1988年   2篇
  1987年   2篇
  1986年   4篇
  1985年   6篇
  1984年   2篇
排序方式: 共有379条查询结果,搜索用时 328 毫秒
21.
The coding regions of Ag85B MPT-64, and ESAT-6 secreted proteins were cloned initially into the eukaryotic expression vector pJW4303, then transformed to E. coli Top 10 strain for plasmid DNA extraction and further analysis. Plasmids containing the right insertion were sequenced to confirm their identity. COS7 cells were transfected with a mixture containing serially diluted plasmid DNA encoding three secreted proteins and Lipofectin (Gibco). The supernatants and pellets prepared from various cell lines were run on SDS-PAGE gel and the expression of these proteins in COS7 cells were demonstrated by immunoblot using polyclonal or monoclonal antiserum of M.TBH37Rv. 21 days after first vaccination of C57BL-6 mice by all three recombinant eukaryotic expressing vectors, antibody titer for Ag85B reached 1∶3200. 21 days after second vaccination, the antibody titer reached 1∶102400. The highest antibody levels induced by multivalent vaccines after the second injection were equal to or even greater than the highest antibody levels of single DNA vaccine reported in literature after third injections. Antibody titer of MPT-64 was 1∶50 after the first injection and it reached 1∶200 after the second injection. No antigen-specific antibody against ESAT-6 was detected in sera harvested from immunized mice 21 days after both injections. Antigen-specific IFN-g level of Ag85B was 110 pg/mL while no antigen-specific IFN- g level of ESAT-6 and MPT-64 was detected even after third injections. To our knowledge, it is the first time that studies of polyvalent recombinant DNA vaccines against TB were carried out in C57BL-6 mice. Our results indicated that multiple DNA vaccines could be used to enhance protective responses against M.TB.  相似文献   
22.
23.
The neural stem cells in the anterior subventricular zone (SVZa) mainly generate the progenitors that will differentiate into neurons, and along a highly circumscribed migratory access Rostral migratory stream (RMS), they migrate to the olfactory bulbs (OB). To understand the effects of BMPs on SVZa neural stem cells, in this study BMP4 at various concentrations was used to induce SVZa neural stem cells, and the living cell labeling using BMP4 promotor conjugated with red fluorescence protein showed the expression of BMP4 dynamically. The results demonstrated that low BMP4 doses (1-5 ng/mL) promoted while high doses (10-100 ng/mL) inhibited the proliferation of SVZa neural stem cells, and BMP4 promotedneuron differentiation in the early stage (1-3 d), howeverm, it inhibited the neuron commitment after 4 d. Noggin, the antagonist of BMP4, blocked the physiological effects of BMP4. In OB, BMP4 is mainly to accelerate the progenitors to withdraw from the cell cycle and trigger the differentiation, and in RMS, it promotes the proliferation of committed progenitors and not differentiation, further in SVZa, BMP4 enhances astrocyte commitment.  相似文献   
24.
25.
海洋生物黏附蛋白研究进展   总被引:2,自引:0,他引:2  
海洋附着生物粘合蛋白的研究对于生物粘合剂的开发及海洋防污行业均具有重要的意义。综述了对贻贝足丝蛋白,藤壶胶蛋白以及管栖毛虫管胶蛋白的研究进展。3种不同生物的黏附蛋白具有某些相似性,同时又各有其结构特点,对其蛋白质结构,功能及粘合机制的研究既具有重要的学术意义也具有广阔的应用前景。  相似文献   
26.
用生化抽提细胞质膜蛋白和SDS-梯度聚丙烯酰胺凝胶电泳等方法比较gp150突变AK127细胞和野生型KAx-3细胞质膜蛋白的结果显示,各发育时期的AK127细胞和KAx-3细胞在含量方面比较恒定的质膜蛋白组分是68 kD,60 kD,54 kD,50 kD,37 kD,34 kD和31 kD条带,它们并不因为AK127细胞缺失gp150分子而有所改变.发育12 h后,蛋白含量变化最为明显的是45 kD,25 kD,20 kD和17 kD蛋白,由于同时期突变细胞的这些蛋白条带含量没什么变化,推测这些条带的变化与gp150分子有密切关系;同时野生型细胞还增加了两条10~12 kD蛋白条带,这些蛋白可能与gp150分子一样在发育中有表达的时间性和空间性,且与细胞信号传递有密切关系.  相似文献   
27.
对碱提法回收猪骨蛋白质工艺参数的研究表明,4种工艺参数对蛋白质得率均有不同程度的影响。其顺序为浸提液pH>浸提时间>沉降pH>浸提温度。碱提法回收猪骨蛋白质的最高得率为25.7%,最佳工艺参数为浸提时间105min,浸提液pH12.0,浸提温度30℃和沉降pH5.0。  相似文献   
28.
Summary Proteins immunologically related toRhynchosciara americana larval protein 10 occur in the hemolymph and ovaries of five different fly species of the genusRhynchosciara. Electrophoretic analyses showed these proteins to have a mol.wt similar to that of theR. americana protein 10 (43,000), e.g. theR. hollanderi protein 44,300, theR. milleri protein 45,500.  相似文献   
29.
Functions of fatty acid binding proteins   总被引:1,自引:0,他引:1  
Summary Cytosolic fatty acid binding proteins (FABP) belong to a gene family of which eight members have been conclusively identified. These 14–15 kDa proteins are abundantly expressed in a highly tissue-specific manner. Although the functions of the cytosolic FABP are not clearly established, they appear to enhance the transfer of long-chain fatty acids between artificial and native lipid membranes, and also to have a stimulatory effect on a number of enzymes of fatty acid metabolism in vitro. These findings, as well as the tissue expression, ligand binding properties, ontogeny and regulation of these proteins provide a considerable body of indirect evidence supporting a broad role for the FABP in the intracellular transport and metabolism of long-chain fatty acids. The available data also support the existence of structure- and tissue-specific specialization of function among different members of the FABP gene family. Moreover, FABP may also have a possible role in the modulation of cell growth and proliferation, possibly by virtue of their affinity for ligands such as prostaglandins, leukotrienes and fatty acids, which are known to influence cell growth activity. FABP structurally unrelated to the cytosolic gene family have also been identified in the plasma membranes of several tissues (FABPpm). These proteins have not been fully characterized to date, but strong evidence suggests that they function in the transport of long-chain fatty acids across the plasma membrane.  相似文献   
30.
Aquaporins are implicated in a wide variety of plant physiological processes, although the mechanisms involved in their regulation are not fully understood. To gain further insight into the regulatory factors involved in this process, we used a yeast two-hybrid system to screen for potential binding partners to the Arabidopsis tonoplast intrinsic protein (TIP) AtTIP1;1. This was the first protein identified to be associated with high water permeability in vacuolar membranes from Arabidopsis thaliana. Using ...  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