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   191篇
  免费   12篇
  国内免费   13篇
  2023年   1篇
  2022年   2篇
  2021年   7篇
  2020年   2篇
  2019年   3篇
  2018年   8篇
  2017年   6篇
  2016年   6篇
  2015年   1篇
  2014年   7篇
  2013年   7篇
  2012年   11篇
  2011年   6篇
  2010年   17篇
  2009年   7篇
  2008年   10篇
  2007年   5篇
  2006年   4篇
  2005年   8篇
  2004年   5篇
  2003年   8篇
  2002年   5篇
  2001年   5篇
  2000年   3篇
  1999年   6篇
  1998年   4篇
  1997年   3篇
  1996年   3篇
  1995年   6篇
  1994年   5篇
  1993年   3篇
  1992年   2篇
  1991年   7篇
  1990年   3篇
  1989年   3篇
  1988年   3篇
  1987年   2篇
  1986年   1篇
  1985年   4篇
  1984年   2篇
  1983年   2篇
  1982年   2篇
  1981年   3篇
  1980年   1篇
  1979年   3篇
  1978年   3篇
  1977年   1篇
排序方式: 共有216条查询结果,搜索用时 31 毫秒
141.
朱帆  毛歆  李文鑫 《动物学报》2001,47(3):329-332
用Southern杂交法研究Quox-1基因在人正常白细胞、LCE细胞及其HeLa细胞中的限制性酶切片段多态性;免疫组织化学方法研究Quox-1基因在人细胞中的表达。结果表明:在正常人细胞DNA中存在鹌鹑Quox-1基因的同源序列,在LCE等肿瘤细胞中Quox-1基因表现出明显的限制性酶切片段多态性和基因扩增现象。Quox-1蛋白在HeLa、LCE等肿瘤细胞中激活表达,而在正常人白细胞未检测出Quox-1基因的表达。Quox-1基因同人类的肿瘤发生、发展和癌变具有一定的相关性。  相似文献   
142.
Three polysaccharides, two heteroglycans (PL-1 and PL-4) and one glucan (PL-3), were solubilized from the fruit bodies of Ganoderma lucidum and isolated by anion-exchange and gel-filtration chromatography. Their structural features were elucidated by glycosyl residue and glycosyl linkage composition analyses, partial acid hydrolysis, acetolysis, periodate oxidation, 1D and 2D NMR spectroscopy, and ESI-MS experiments. The data obtained indicated that PL-1 had a backbone consisting of 1,4-linked alpha-D-glucopyranosyl residues and 1,6-linked beta-D-galactopyranosyl residues with branches at O-6 of glucose residues and O-2 of galactose residues, composed of terminal glucose, 1,6-linked glucosyl residues and terminal rhamnose. PL-3 was a highly branched glucan composed of 1,3-linked beta-D-glucopyranosyl residues substituted at O-6 with 1,6-linked glucosyl residues. PL-4 was comprised of 1,3-, 1,4-, 1,6-linked beta-D-glucopyranosyl residues and 1,6-linked beta-D-mannopyranosyl residues. These polysaccharides enhanced the proliferation of T- and B-lymphocytes in vitro to varying contents and PL-1 exhibited an immune-stimulating activity in mice.  相似文献   
143.
An affinity chromatographic method with a novel eluant from Bacillus licheniformis is described. α-amylase was bound to starch, starch-celite, starch-Sepharose columns and the bound α-amylase was rapidly eluted with 2% (w/v) white dextrin. The binding capacity of α-amylase to starch column is 380 μmol/g of starch. The purified enzyme showed a single polypeptide on SDS-polyacrylamide gel electrophoresis with a molecular weight of 58 kD. The specificity of purified enzyme was confirmed by immunodiffusion, immunoelectrophoresis. Single radial immunodiffusion and western blotting studies analyzed the synthesis of enzyme at different time points.  相似文献   
144.
Mercury is a heavy metal that can cause a variety of toxic effects on the organism, such as hematological and immunological alterations. In the present investigation, deleterious effects of mercury-intoxication in mice and a possible protective effect of diphenyl diselenide (PhSe)(2) were studied. Male adult Swiss albino mice received daily a pretreatment with (PhSe)(2) (15.6 mg/kg, orally) for 1 week. After this week, mice received daily mercuric chloride (1 mg/kg, subcutaneously) for 2 weeks. A number of hematological (erythrocytes, leukocytes, platelets, hemoglobin, hematocrit, reticulocytes, and leukocytes differential) and immunological (immunoglobulin G and M plasma concentration) parameters were evaluated. Another biomarker of tissue damage, lactate dehydrogenase (LDH), was also determined. The results demonstrated that mercury exposure caused a reduction in the erythrocyte, hematocrit, hemoglobin, leukocyte, and platelet counts and an increase in the reticulocyte percentages. (PhSe)(2) was effective in protecting against the reduction in hematocrit, hemoglobin, and leukocyte levels. (PhSe)(2) ameliorated reticulocyte percentages increased by mercury. However, (PhSe)(2) was partially effective in preventing against the decrease in erythrocyte and platelet counts. Immunoglobulin G and M concentrations and LDH activity were increased by mercury exposure, and (PhSe)(2) was effective in protecting against these effects. In conclusion, (PhSe)(2) was effective in protecting against hematological and immunological alterations induced by mercury in mice.  相似文献   
145.
在单纯疱疹病毒1型(herpes simplex virus type 1,HSV-1)小鼠感染及其相关研究中,临床病理和免疫学指标对其分析具有重要技术意义。本研究观察了HSV-1在不同条件下感染BALB/c小鼠后的多个免疫学指标,包括外周血单核细胞(peripheral blood mononuclear cell,PBMC)群体中树突细胞比例及功能、血清中和抗体水平、PBMC中HSV-1抗原特异性T细胞水平,以及潜伏感染期小鼠神经组织中CD8 T细胞浸润情况。结果显示,HSV-1毒株Mckrae、17+以角膜及滴鼻途径感染3周龄及6周龄BALB/c小鼠后,小鼠PBMC中树突细胞数量增加,并显示出刺激病毒抗原特异性T细胞增殖的能力。病毒感染后35 d,小鼠PBMC中未检测到白细胞介素4(interleukin 4,IL-4)抗原特异性T细胞,但能检测到低水平的γ干扰素(interferon γ,IFN-γ)抗原特异性T细胞;小鼠血清中未检测到或仅能检测到低水平的中和抗体。HSV-1以皮下及足垫注射途径感染BALB/c小鼠90 d后,足垫感染途径较皮下感染诱导出更高水平的血清中和抗体,PBMC中可检测到IL-4及IFN-γ抗原特异性T细胞,但不同毒株及小鼠周龄之间出现T细胞反应程度差异。组织病理学结果表明,各组小鼠三叉神经组织中均有CD8 T细胞浸润。这些结果提示,不同HSV-1毒株以不同途径感染不同周龄BALB/c小鼠后,均可刺激树突细胞成熟及呈递病毒抗原,但血清中和抗体及PBMC中病毒抗原特异性T细胞水平在不同毒株、感染途径及小鼠周龄之间有差异。  相似文献   
146.
用中药复方免不1号,免不2号治疗免疫性不育雄鼠,观察睾丸,附睾组织学和免疫组化的变化。用精子抗原免疫昆明种雄性小白鼠,建立免疫性不育动物模型。同时分别饲喂中药复方免不1号,免不2号,醋酸强的松,生理盐水;从组织学和免疫组化等方面观察免疫性不育症的变化。结果显示免疫性不育雄鼠血清,精囊液抗精子抗体高,睾丸间质,睾丸曲细精管界膜,精原细胞,附睾管上皮细胞免疫复合物沉积多,睾丸每曲细精管精子和晚期精子细胞减少,中药免不1号和2号能降低抗精子抗体,清除免疫复合物的沉积,恢复曲细精管精子和晚期精子细胞数。结果表明:免不1号和2号通过调节全身免疫系统,清除循环和局部的抗精子抗体,免疫复合物,提高精子和精子细胞数,从而提高小鼠的受孕率。  相似文献   
147.
Microbial superantigens can alter host immunity through aberrant activation and subsequent anergy of responding naive T cells. We show here that the superantigen, staphylococcal enterotoxin B (SEB), directly induces tolerance in memory CD4 T cells. Murine naive and memory CD4(+) T cells were labeled with the fluorescent dye CFSE and the cells were exposed to SEB before they were cultured with specific peptide antigen. Memory, but not naive, T cells became anergic and did not respond to their cognate peptide antigen. The extent and duration of T cell receptor (TCR) clustering was similar to promote naive T cell activation and memory T cell anergy, suggesting similar TCR-SEB interactions led to distinct intracellular signaling processes in the two cell types. Like SEB, soluble anti-CD3 mAb does not stimulate memory cell proliferation. However, unlike SEB, soluble anti-CD3 mAbs did not induce anergy to cognate peptide. Anergy was directly visualized in vivo. CD4(+) memory T cells were identified in mice that had been administered SEB. The cells failed to proliferate in response to subsequent immunization with their cognate recall antigen. Hence, one mode of pathogen survival is the modulation of host immunity through selective elimination of memory T cell responses.  相似文献   
148.
Urano M  Tanaka C  Sugiyama Y  Miya K  Saji S 《Cryobiology》2003,46(3):238-245
Cryoablation is a low-invasive surgical treatment for malignant tumors. It may induce an immunological response leading to the eradication of distant metastases or alternatively it might promote the growth of residual tumors. In this paper we confirm the occurrence of both phenomena and we describe the preventive effect of a protein-bound polysaccharide preparation. Metastatic liver tumors were produced in BALB/c mice by the intrasplenic inoculation of colon 26 cells and cryoablation was carried out using liquid nitrogen (-170 degrees C) applied by a contact method. The value of combining cryoablation with administration of the polysaccharide preparation in the prevention of growth of residual tumors was investigated. It was shown that the number of metastatic liver nodules and the size of the primary tumor at the site of inoculation in the spleen were significantly lower when the volume that was frozen was small. The production by splenocytes of the tumor necrosis factor TNF-alpha, interferon INF-gamma, and the interleukins IL-4 and IL-10 increased significantly after freezing and thawing of the tumor tissue. The polysaccharide treatment significantly reduced the production of IL-4 and IL-10 following cryoablation; the production of TNF-alpha and INF-gamma was slightly promoted; the natural killer and cytotoxic T-cell activities of splenocytes were slightly enhanced. It was concluded that the polysaccharide preparation was beneficial by suppressing IL-4 and IL-10 production and might inhibit the growth of residual tumor that is sometimes induced by large-volume cryoablation.  相似文献   
149.
This study demonstrates a synergistic action of prostaglandin E and GM-CSF which causes the release of pro-tolerant cytokines in two monocyte cell lines: U937 and ML-1. The prostaglandin effect is cyclic AMP dependent since stimulators of adenyl cyclase such as forskolin (fsk) can replace PGE. Fsk and GM-CSF combinations raised messenger RNA for IL-10, interleukin-1 receptor antagonist (IL-1ra), and CD14 as well as the released proteins. Effective levels of interleukin 12 are reduced. In these respects, the monocyte cells resemble the alternatively activated or tumour associated macrophages. A differential pattern in co-stimulatory molecule expression is seen; CD80 is unchanged but CD86 is markedly elevated and such a change is not seen in the alternatively activated macrophage but has been previously reported in monocytes resident in the non-inflamed gut. Control of leukocyte responses by two agents acting in synergy could be effective in critical situations such as discrimination between pathogens and commensal bacteria, etc. Monocytes modified in such a way could provide a pro-tolerant environment (high IL-10, low IL-12) for antigen presentation by dendritic cells and thus may contribute to a normally permissive milieu, e.g., for food absorption.  相似文献   
150.
Exposure to organophosphorus compounds (OPs), in the form of nerve agents and pesticides poses an ever increasing military and civilian threat. In recent years, attention has focused on the use of exogenously administered cholinesterases as an effective prophylactic treatment for protection against OPs. Clearly, a critical prerequisite for any potential bioscavenger is a prolonged circulatory residence time, which is influenced by the size of protein, the microheterogeneity of carbohydrate structures, and the induction (if any) of anti-enzyme antibodies following repeated injections of the enzyme. Previously, it was demonstrated that multiple injections of equine butyrylcholinesterase (BChE) into rabbits, rats, or rhesus monkeys, resulted in a mean residence time spanning several days, and variable immune responses. The present study sought to assess the pharmacokinetics and immunological consequences of administration of purified macaque BChE into macaques of the same species at a dose similar to that required for preventing OP toxicity. An i.v. injection of 7,000 U of homologous enzyme in monkeys demonstrated much longer mean residence times in plasma (MRT = 225 +/- 19 h) compared to those reported for heterologous Hu BChE (33.7 +/- 2.9 h). A smaller second injection of 3,000 U given four weeks later, attained predicted peak plasma levels of enzyme activity, but surprisingly, the MRT in the four macaques showed wide variation and ranged from 54 to 357 h. No antibody response was detected in macaques following either injection of enzyme. These results bode well for the potential use of human BChE as a detoxifying drug in humans.  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