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   208篇
  免费   9篇
  国内免费   10篇
林业   1篇
农学   2篇
  1篇
综合类   43篇
农作物   3篇
水产渔业   9篇
畜牧兽医   156篇
园艺   11篇
植物保护   1篇
  2022年   1篇
  2021年   4篇
  2020年   6篇
  2019年   10篇
  2018年   3篇
  2017年   6篇
  2015年   7篇
  2014年   10篇
  2013年   4篇
  2012年   15篇
  2011年   20篇
  2010年   6篇
  2009年   12篇
  2008年   6篇
  2007年   17篇
  2006年   8篇
  2005年   15篇
  2004年   5篇
  2003年   7篇
  2002年   7篇
  2001年   6篇
  2000年   5篇
  1999年   3篇
  1998年   5篇
  1996年   4篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1992年   2篇
  1991年   4篇
  1990年   1篇
  1989年   4篇
  1988年   2篇
  1986年   2篇
  1985年   1篇
  1984年   2篇
  1983年   2篇
  1981年   1篇
  1980年   6篇
  1979年   4篇
排序方式: 共有227条查询结果,搜索用时 39 毫秒
151.
The purpose of this study was to study the efficacy and effect of compound Banqing soluble powder in preventing and treating chickens infected with infectious bronchitis virus.The chickens were randomly divided into prevention group,treatment group,Shuanghuanglian control group,Maxing Shigan control group,model control group and blank control group.Among them,the prevention group and the treatment group were divided into high,middle and low dose groups respectively.Except for the blank control group,the prevention group was given drugs through drinking water for 3 consecutive days from 12 days old,and then the 15-day-old chicks were exposed to 0.2 mL infectious bronchitis virus by nasal drip,and the treatment group was given drinking water for 6 days.The number of infected and cured chickens were collected during the experiment,the incidence,protection rate and cure rate were calculated,and the index of immune organs,the ability of lymphocyte proliferation and the levels of cytokines IL-2,IL-4,TNF-α and IFN-α in serum were detected to explore the preventive and therapeutic effect of compound Banqing soluble powder on IBV infected chicks.The results of this experiment showed that the protective rate of compound banqing soluble powder against high dose group could reach 66.67%,and the cure rate of the treatment middle dose group was 83.33%.On the other hand,it increased the immune organ index of infected chicks,after exposure 4 and 10 d,the proliferative capacity of T lymphocytes and B lymphocytes in each administration group was significantly higher than that of the model control group (P<0.05).It could also regulate the levels of IL-2,IL-4,TNF-α and IFN-α in serum to maintain dynamic balance,after the challenge (5 and 11 d),the middle-dose group of IL-4 and IFN-α levels were significantly higher than the model control group (P<0.05).Synthesizing the test data,compound Banqing soluble powder had a good effect on the prevention and treatment of infectious bronchitis,and the therapeutic effect was better than the preventive effect.Among them,the preventive high dose group and the middle dose group were the most effective.  相似文献   
152.
AIM: To study the expressing variation of TNF-α and IFN-γ mRNA in mouse splenocytes induced by H22 tumor cells derived heat shock protein gp96-peptide complexes in vitro,and to observe the morphologic change of H22 tumor cells which treated with the culture supernatant.METHODS: H22 tumor cells derived HSP gp96 was obtained by the techniques for protein extraction and purification and was identified by Western blotting method.The expression values of TNF-α and IFN-γ mRNA in spleen lymphocytes were detected by semi-quantitative RT-PCR.The morphologic changes of H22 tumor cells induced by the culture supernatant were observed by laser scanning confocal microscopy (LSCM) and transmission electron microscope (TEM).RESULTS: Purified heat shock protein gp96 was identified by Western blotting.The expression value of TNF-α and IFN-γ mRNA in activated spleen lymphocytes induced by gp96-peptide complexes was higher than that in control groups (P<0.05).The morphologic change of apoptosis of H22 tumor cells,which treated by the culture supernatant of experimental group was observed with LSCM and TEM.CONCLUSION: Heat shock protein gp96-peptide complexes increase the expression value of TNF-α and IFN-γ mRNA in spleen lymphocytes of mouse in vitro.Besides,apoptosis of H22 cells is induced by immunologic active material secreted by activated splenocytes.  相似文献   
153.
不同月龄山羊小肠黏膜免疫相关细胞的数量变化   总被引:6,自引:1,他引:6  
为揭示不同发育阶段山羊小肠黏膜免疫特点的内在规律,本试验采用组织学和组织化学方法,对0.5、2和12月龄山羊小肠不同肠段的上皮内淋巴细胞、杯状细胞和肥大细胞的分布和数量变化进行了比较研究。结果显示:随着年龄增长,小肠各段上皮内淋巴细胞和肥大细胞的数量逐步增多(P〈0.05),而杯状细胞却逐渐减少(P〈0.05)。上皮内淋巴细胞数从十二指肠至回肠逐渐减少,0.5月龄的回肠上皮内淋巴细胞数仅是十二指肠和空肠的84.45%和98.14%(P〈0.05),肥大细胞的分布规律与上皮内淋巴细胞相似;相反,杯状细胞数从十二指肠至回肠逐渐增多。以上结果提示,在山羊小肠的早期发育中,杯状细胞起着重要的黏膜屏障功能,随着肠道黏膜免疫系统的发育,上皮内淋巴细胞和肥大细胞的黏膜防御作用进一步增强。  相似文献   
154.
Cytotoxic peptides were isolated from a trypsin digest of bovine αs1‐casein by a combination of ion‐exchange column chromatography and reversed‐phase high‐performance liquid chromatography as an indicator of cytotoxicity toward mouse spleen cells. Amino acids of the isolated peptides were sequenced as arginyl‐proly‐lysine, leucyl‐lysyl‐lysine and tyrosyl‐lysine, being compatible with sequences 1–3, 101–103 and 104–105 of bovine αs1‐casein, respectively. The isolated peptides displayed cytotoxicity toward healthy mouse T and B cells and human leukemic T and B cell lines in a commercially available serum‐free medium for lymphocytes, Celgrosser‐P, and were named α‐casecidins. Similar cytotoxicity was confirmed in chemically synthesized peptides corresponding to sequences 1–3, 101–103 and 100–105 of bovine αs1‐casein. The cytotoxicity induced by α‐casecidins was concluded to be because of necrosis, and was diminished in the presence of bovine serum albumin.  相似文献   
155.
A sensitive and specific radioimmunoassay for the major internal antigen of bovine leukemia virus has been applied to detecting this protein in cultured lymphocytes of infected cattle. The specificity inherent in this assay offers obvious advantages over a previously described syncytium induction assay for infectious bovine leukemia virus, because false positive reactions due to other viruses such as bovine syncytial virus are avoided. Investigations of various culture conditions indicated that maximal amounts of antigen had been produced after incubation for 72 hr at 37°C. Lymphocyte concentrations of 106?5×107 cells/ml gave satisfactory results. Tests of cultured lymphocytes from bovine leukemia virus infected or bovine leukemia virus-free cattle indicated a comparable sensitivity between the radioimmunoassay and syncytium induction assay in the detection of bovine leukemia virus infections.  相似文献   
156.
重组牛白细胞介素-2对不同种属动物淋巴细胞的作用   总被引:2,自引:0,他引:2  
以重组牛白细胞介素-2作用于ConA活化的不同种属动物的淋巴细胞,结果发现重组牛白细胞介素-2对人、犬、猪、绵羊以及鸡淋巴细胞没有作用;对山羊、豚鼠及小鼠淋巴细胞具有显著作用;对牛、驴和兔淋巴细胞具有极显著的作用。  相似文献   
157.
T‐cell large granular lymphocytic leukemia (T‐cell LGLL) is the most common presentation of chronic lymphocytic leukemia (CLL) in dogs. Aleukemic or subleukemic leukemia is a particularly rare variation in both humans and dogs, where bone marrow proliferation is either not or only sparsely translated in the peripheral blood. Neutropenia is a prominent feature in cases of human T‐cell LGLL but is normally absent in canine CLL. This report describes a case of a dog presented with an almost 3‐year history of asymptomatic neutropenia, lymphopenia, and thrombocytopenia (without anemia). A bone marrow examination, the exclusion of infectious diseases, and clonality testing led to the diagnosis of subleukemic LGLL that responded well to therapy (death occurred 2.5 years later due to an unrelated cause).  相似文献   
158.
This study examined the mitogenic response of bovine peripheral T lymphocytes to leptin, a pleiotropic hormone regulating food intake and energy expenditure. Leptin alone slightly suppressed proliferation of T lymphocytes in the presence of concanavalin A (ConA). Leptin also inhibited proliferation of T lymphocytes induced by anti-CD3 antibody. ConA treatment activated some protein kinases, including p44/p42(MAPK) and Akt/PKB, while anti-CD3 antibody treatment increased mRNA expression of suppressor of cytokine signalling (SOCS) 3, interferon (IFN)gamma, interleukin (IL) 2 and IL4 in T lymphocytes. Leptin alone increased only SOCS3 mRNA expression. Simultaneous treatment with mitogens and leptin enhanced IFNgamma mRNA expression but decreased IL2 mRNA expression, without any synergistic effect on phosphorylation of protein kinases or mRNA expression of SOCS3 and IL4. These results suggest that leptin modulates bovine T lymphocyte functions.  相似文献   
159.
Ten parasite-free lambs were drenched with oxfendazole on days 0 and 28 and, one day after each drench, were injected with human erythrocytes and ovalbumin. Ten other antigen-injected lambs were not drenched (controls). Lymphocytes collected 3 days after each antigen injection and cultured in RPMI 1640 plus 5% fetal calf serum (FCS) and lymphocytes collected 3 days after the first and 3 and 7 days after the second antigen injection and cultured in 50% autologous serum had decreased blastogenic activity compared with control lymphocytes. After the second drench, decreased blastogenesis was seen with lymphocytes collected on days 3 and 7 and cultured in 5% FCS and concanavalin A (Con A) and on day 3 when cultured in 5% FCS and phytohaemagglutinin (PHA). Decreased blastogenesis was also seen with lymphocytes collected 7 and 29 days after the second injection of antigen and cultured in 50% autologous serum plus Con A and on days 3, 7 and 29 when cultured in 50% autologous serum and PHA.Significantly depressed antibody responses to both antigens were seen after the second drench. The serum complement level was depressed 3 days after the second injection of antigen. Serum nitric oxide levels were significantly depressed 3 and 21 days after the first and 7 and 21 days after the second injection of antigen. There were no differences in levels of growth-promoting hormones but the drenched lambs gained significantly more weight than the controls.Abbreviations C complement - Con A concanavalin A - cpm counts per minute - EIA enzyme immunoassay - FCS fetal calf serum - IGF insulin-like growth factor - oIGF-1 ovine insulin-like growth factor-1 - PBS phosphate-buffered saline - PHA phytohaemagglutinin  相似文献   
160.
【目的】构建猪淋巴细胞基因文库,初步绘制正常猪外周血淋巴细胞的基因表达谱,为进一步筛选免疫相关基因提供平台。【方法】以mRNA为模板,经反转录酶催化,在体外反转录成cDNA,与质粒载体连接后转化大肠杆菌,进一步扩增后,获得猪外周血淋巴细胞全部mRNA信息的cDNA克隆集合,并进行序列分析和注释。【结果】构建了正常猪外周血淋巴细胞cDNA文库,获得库容量为1.2×10^6PFU/mL、重组率为93.3%、85%插入片段处于750~2000bp的高质量文库;随机测定1100条ESTs,经拼接和聚类,获得152条高表达的基因重叠群(Contigs)和619条低表达基因——单拷贝的EST(Singletons);经序列比对分析,发现23.3%ESTs为与任何物种都没有匹配的新基因,75.9%ESTs为与猪没有匹配的新基因。用GO数据库对获得的EST进行基因功能分类和KEGG路径图分析,发现丝裂原活化蛋白激酶途径(Mitogenn—activated protein kinase,MAPK)、钙信号通路、胰岛素信号通路、脂肪细胞因子信号通路、Toll—like受体信号通路、B细胞受体信号通路和T细胞受体信号通路的基因均有较高表达。【结论】大部分的猪外周血淋巴细胞基因尚未被分离和鉴定出来,但这些基因mRNA转录和表达丰度均较高,且在猪外周血淋巴细胞中起着非常重要的作用。  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