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   127篇
  免费   10篇
  2023年   1篇
  2021年   2篇
  2020年   4篇
  2019年   1篇
  2018年   3篇
  2017年   3篇
  2016年   7篇
  2015年   3篇
  2014年   2篇
  2013年   6篇
  2012年   3篇
  2011年   12篇
  2010年   6篇
  2009年   1篇
  2008年   3篇
  2007年   4篇
  2006年   5篇
  2005年   2篇
  2004年   4篇
  2003年   1篇
  2002年   5篇
  2001年   3篇
  2000年   3篇
  1999年   6篇
  1998年   6篇
  1996年   1篇
  1994年   2篇
  1993年   2篇
  1991年   6篇
  1989年   2篇
  1988年   2篇
  1987年   2篇
  1986年   3篇
  1984年   4篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   3篇
  1976年   2篇
  1975年   4篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
排序方式: 共有137条查询结果,搜索用时 31 毫秒
1.
PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4+ and CD8+ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.  相似文献   
2.
We confirmed that NADPH-dependent anaerobic amaranch reduction in rat liver microsomes is compatible with the interaction of the dye with Fe(III) heme of cytochrome P-450 as the type II substrate. This process is rate-limiting in the whole reaction. High positive correlation (r = 0.949) between the values of Vmax for reaction of NADPH-dependent anaerobic amaranch reduction and the relative content low spin forms of cytochrome P-450 determined by ESR in microsomes from liver of control and induced by PB, BP, IS and 4-MP rats was observed. Relative content of low spin forms of cytochrome P-450 determined by ESR was increased according to BP less than PB less than control less than IS approximately 4-MP; Vmax values increased according to BP less than PB less than control less than IS less than 4-MP. Thus, reaction of NADPH-dependent anaerobic amaranch reduction may be used for determination of low spin forms of cytochrome P-450 at physiological conditions.  相似文献   
3.
Cultured bovine capillary endothelial (BCE) cells produce low levels of collagenolytic activity and significant amounts of the serine protease plasminogen activator (PA). When grown in the presence of nanomolar quantities of the tumor promoter 12-O-tetradecanoyl phorbol-13-acetate (TPA), BCE cells produced 5-15 times more collagenolytic activity and 2-10 times more PA than untreated cells. The enhanced production of these enzymes was dependent on the dose of TPA used, with maximal response at 10(-7) to 10(-8) M. Phorbol didecanoate (PDD), an analog of TPA which is an active tumor promoter, also increased protease production. 4-O-methyl-TPA and 4α-PDD, two analogs of TPA which are inactive as tumor promoters, had no effect on protease production. Increased PA and collagenase activities were detected within 7.5 and 19 h, respectively, after the addition of TPA. The TPA-stimulated BCE cells synthesized a urokinase-type PA and a typical vertebrate collagenase. BCE cells were compared with bovine aortic endothelial (BAE) cells and bovine embryonic skin (BES) fibroblasts with respect to their production of protease in response to TPA. Under normal growth conditions, low levels of collagenolyic activity were detected in the culture fluids from BCE, BAE, and BES cells. BCE cells produced 5-13 times the basal levels of collagenolytic activity in response to TPA, whereas BAE cells and BES fibroblasts showed a minimal response to TPA. Both BCE and BAE cells exhibited relatively high basal levels of PA, the production of which was stimulated approximately threefold by the addition of TPA. The observation that BCE cells and not BAE cells produced high levels of both PA and collagenase activities in response to TPA demonstrates a significant difference between these two types of endothelial cells and suggests that the enhanced detectable activities are a property unique to bovine capillary and microvessel and endothelial cells.  相似文献   
4.
Parafollicular cells (PC) of the sheep thyroid gland are neural crest derivatives that synthesize and release the biogenic amine serotonin (5-HT) as well as the hormone calcitonin. The thyroid also contains a highly specific serotonin-binding protein (SBP). Separation of dissociated thyroid cells was done to study the cellular localization of SBP and to develop a means of isolating PC for study. Various methods were used to obtain an enriched and purified population of PC. Minced thyroid glands were enzymatically dissociated and the cells were layered on a Ficoll linear density gradient. Fractions obtained from the gradient were examined for cell number, viability, 5-HT concentration, SBP activity, and morphology by electron microscopy. One of the fractions was found to be enriched in PC. High levels of 5-HT and SBP were also found in this fraction, whereas these levels were low where the majority of cells were found. This PC-rich fraction, however, contained numerous follicular cells (FC); therefore, additional approaches to cell separation were used. FC can be stimulated in vitro with thyroid stimulating hormone (TSH) to become intensely phagocytic. When stimulated cells were incubated in the presence of silica microspheres, the FC engulfed the microspheres, which were toxic to them. PC did not become phagocytic and were unharmed by the microspheres. Suspended cells, after incubation with microspheres, were centrifuged on a discontinuous gradient, and a PC-rich fraction was obtained. Silica, however, interfered with analysis of SBP. Another method to take advantage of the phagocytic potential of FC was therefore used. TSH-stimulated cell suspensions were passed through a column of sepharose to which thyroglobulin had been coupled. Stimulated FC apparently adhered to the beads and were retained by the columns. Fractions eluting from the columns were greatly enriched with PC. These fractions contained high levels of 5-HT and SBP, and considerably reduced FC contamination was found by quantitative electron microscopy. It is concluded that SBP is localized to PC in the sheep thyroid. The idea that these cells resemble serotonergic neurons in their mechanisms of 5-HT storage is supported.  相似文献   
5.
The ultrastructure of the mid-intestine of four sturgeon species and their hybrids was studied. Apart from enterocytes and glandular goblet cells, the cells with microvilli, endocrine cells, and immunocompetent elements were revealed. Specific cells responsible for the primary immune response, analogous to mammalian M-cells, were discovered in sturgeon fishes. The ultrastructural characteristics common for the mid-intestinal epithelium of all the sturgeon fishes studied were determined. Species-specific features of intestinal epithelium of the parent species, which were characteristic of the hybrids, were revealed.  相似文献   
6.
Molecular Biology - Molecular profiling of tumors may provide promising options for personalized treatment. We have examined the spectrum of germline and somatic mutations in 23 breast cancers (BC)...  相似文献   
7.
In a three-hour bioassay, we tested the palatability and feeding preferences of Uresiphita maorialis (kōwhai moth) for Sophora tetraptera, Sophora microphylla and Sophora prostrata. Palatability tests showed no differences among the Sophora species. Feeding preferences, on the other hand, showed that S. tetraptera and S. microphylla leaves are preferred over S. prostrata leaves. Our results support our field observations in Wellington city parks and gardens showing that S. tetraptera and S. microphylla plants frequently have higher densities of larvae than S. prostrata.  相似文献   
8.
9.
Korneva ZhV 《Parazitologiia》2004,38(2):150-159
The fine structure of the female reproductive organs and ducts in two cyclophyllidean cestodes was studied by transmission electron microscopy. All the studied ducts (vitelline, fertilization and vaginal ducts, and oviducts) as well as the uterine and ootype walls have the luminal surface elevated to form apical cytoplasmic lamellae and are surrounded by bands of circular muscules, which are attached to the basement layer. The structure of the studied ducts epithelium corresponds to the pattern described in other ducts of the cestode genital system, namely a nucleate syncytial layer. An exception is the vagina Sobolevicanthus gracilis, in which the surface is lined with not numerous atypical microtriches. The comparison of our results and the data reported for other species is given. It is found out that in different species of cestodes forming oligolecital eggs, there are observed various uterine structures and diverse contacts between the eggs capsules and the uterine epithelium. The formation of special structures and contacts is the evolutionary way from the extrauterine type to more progressive intrauterine type of embryo development in cestodes.  相似文献   
10.
We have recently found that matrix metalloproteinases (MMPs) are targets for T-cell and B-cell reactivity in experimental arthritis. In the present article, we investigate whether modulation of MMP-specific T-cell responses could influence the course of adjuvant arthritis (AA). Lewis rats were treated nasally with MMP peptides prior to or after AA induction. Administration of the MMP-10 or the MMP-16 peptide prior to AA induction reduced the arthritic symptoms. In contrast, administration of the MMP-10 peptide after AA induction aggravated the arthritic symptoms. The present study shows the possible usefulness of MMP peptides for immunotherapy. However, a clear understanding of proper timing of peptide administration is crucial for the development of such therapies.  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