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   1286篇
  免费   40篇
  国内免费   90篇
林业   82篇
农学   75篇
基础科学   25篇
  118篇
综合类   474篇
农作物   77篇
水产渔业   32篇
畜牧兽医   250篇
园艺   223篇
植物保护   60篇
  2024年   5篇
  2023年   23篇
  2022年   27篇
  2021年   39篇
  2020年   38篇
  2019年   73篇
  2018年   36篇
  2017年   45篇
  2016年   65篇
  2015年   61篇
  2014年   67篇
  2013年   67篇
  2012年   103篇
  2011年   109篇
  2010年   80篇
  2009年   94篇
  2008年   82篇
  2007年   99篇
  2006年   52篇
  2005年   44篇
  2004年   40篇
  2003年   26篇
  2002年   27篇
  2001年   27篇
  2000年   28篇
  1999年   10篇
  1998年   9篇
  1997年   6篇
  1996年   7篇
  1995年   3篇
  1994年   1篇
  1993年   6篇
  1991年   5篇
  1990年   2篇
  1987年   2篇
  1986年   2篇
  1984年   2篇
  1980年   2篇
  1977年   1篇
  1956年   1篇
排序方式: 共有1416条查询结果,搜索用时 15 毫秒
1.
Single nucleotide polymorphisms (SNPs) of cytokine genes have been found to be involved in the clinical outcome of Tuberculosis. The present study was aimed to identify the high risk genotypes in Tuberculosis patients and their household contacts. A total of 490 subjects were studied which includes 150 active pulmonary tuberculosis patients (APTB), 190 household contacts (HHC) and 150 healthy controls (HC). The SNPs of TNF-α (-308A/G), IL-10(-1082G/A) and IL-6(-174G/C) were performed by ARMs PCR. The IL-10 GA genotype showed significant association in APTB and HHC and was 2.3 times higher risk in APTB and 3.7 times in HHC compared to HCs. The A allele was found to be significantly associated with the risk of disease. The CC genotype of IL-6 was found to be significantly associated in APTB and an insignificant positive association in HHCs. The multifactor dimensionality reduction (MDR) analysis indicated that the genotypes of IL-6 were showing high risk with GA genotype of IL-10. In conclusion the gene interaction may be useful for identification of genotypes as biomarkers to distinguish high risk individuals.  相似文献   
2.
3.
通过对小麦新品种豫麦1O号的观察,认为该品种在上蔡县增产潜力较大。为充分发挥其增产优势,从整地播种,施肥浇水,中、后期管理等方面提出了措施和建议。  相似文献   
4.
AIM:To investigate therapeutic effects of recombinant human growth hormone(rhGH) on rat sepsis and its possible mechanisms.METHODS:Mean arterial pressure (MAP), levels of plasma TNFα, IL-1β and endotoxin, leukocyte count and survival rate within 1 week were determined after E. coli injection among control group, sepsis group and sepsis+rhGH group.RESULTS:(1)rhGH diminished the decrease of MAP, reduced plasma endotoxin and TNFα levels and increased neutrophil ratio in total leukocytes in sepsis rat. rhGH increased survival rate within 1 week on sepsis rat. (2)No changes were found in IL-1β level among the three groups.CONCLUSION:rhGH showed desirable beneficial effects on rat sepsis, which may attribute to: improving circulatory function;maintaining intestinal mucosa barrier, attenuating bacteria/endotoxin translocation and inhibiting the production and release of TNFα.  相似文献   
5.
6.
AIM: The purpose of the present study was to explore the relationship between interleukin-6 mRNA expression and endometriosis. METHODS: Using the rat model, IL-6 mRNA expression in the endometrium was examined by RT-PCR. RESULTS: The expression of IL-6 mRNA in control rats did not change at 2, 4, 6 and 8 weeks after sham operation (P>0.05), but in model rats it gradually increased at 2, 4, 6 and 8 weeks after endometriosis (P<0.01). The expression of IL-6 mRNA in uterine endometrium with endometriosis was lower than in endometriotic tissue, but higher than in endometrium from healthy controls. CONCLUSION: The IL-6 mRNA expression may contribute to the development of endometriosis . The increase in IL-6 mRNA expression may promote the implantation and growth of endometriotic tissue.  相似文献   
7.
AIM: IL-12 acts upon Tlymphocytes and activates its receptor complexes of β1/β2,and so IL-12 can regulate TH1/TH2 balance. Our study is aimed at IL-12-inducing apoptosis of Tcells and expression and signal transduction of Fas/FasLduring Tcell apoptosis. METHODS: The apoptosis of Tcells was detected by Annexin Vstaining cytometry and the expression of Fas/FasLunder different inhibitors were detected by semi-quantitative PCR. RESULTS: IL-12 induced the human leukemic Tcell line(TIB-152) and the human lymphoma Tcell line(HTB-176) and the normal human Tcells to undergo apoptosis. The FasLexpression at 6 hours after treatment with IL-12 increased apparently, and reached the max at 24 hours, and FasLexpression induced by IL-12 was inhibited by PKCinhibitor. But IL-12 did not influence Fas expression. CONCLUSIONS: IL-12 can induce Tcells to undergo apoptosis which is characterized by early membrane changes, the inducing effect is correlated with the concentration of IL-12 and the maturation of Tcells. FasLparticipates in the progression of Tcell apoptosis as a apoptosis mediator, and the effect of IL-12 on FasLexpression may be related with PKCpathway.  相似文献   
8.
AIM: To investigate the activity of interleukin-1β converting enzyme in transplanted intracerebral rat gliomas under angiotensin II-induced hypertension chemotherapy. METHODS: The brain tumor model was produced in Wistar rats by stereotaxic inoculation of C6 glioma cells (1×1012 /L). Tumor-bearing rats were treated with carmustine, teniposide and lisplatin (chemotherapy) during angiotensin II-induced hypertension. Then, the survival time of tumor-bearing rats, tumor blood flow, the concentration of drug, volume of gliomas and the activity of interleukin-1β converting enzyme in glioma were examined.RESULTS: The survival time of tumor-bearing rats was significantly longer in chemotherapy with angiotensin II-induced hypertension group than that of chemotherapy alone. In addition, regional tumor blood flow, the concentration of chemotherapeutic drug and the activity of interleukin -1β converting enzyme in transplanted rat gliomas were increased, while the volume of gliomas was decreased in hypertention chemotherapy group compared with chemotherapy alone. CONCLUSION: Chemotherapy with angiotensin II-induced hypertension has a enhancing effect on chemotherapy for improving the drug delivery to tumor tissue by a increased tumor blood flow and enhancing activity of interleukin -1β converting enzyme.  相似文献   
9.
10.
AIM: To investigate the effect of homocysteine (Hcy) on expression of interleukin-8 (IL-8) mRNA and protein in THP-1-derived macrophages (THP-1 macrophages). METHODS: Cultured THP-1 monocytes were induced to macrophages by 0.1 μmol/L PMA treatment for 72 hours, then the differentiated THP-1 macrophages were incubated with homocysteine (0.01 mmol/L-0.20 mmol/L) for 24 hours, or with 0.10 mmol/L Hcy for various time up to 48 hours. IL-8 protein in THP-1 supernatants was measured by ELISA, and IL-8 mRNA expression was detected by semiquantitive RT-PCR. RESULTS: Compared with control, Hcy significantly increased the expression of IL-8 protein in a concentration-dependent manner. 0.05 mmol/L, 0.10 mmol/L and 0.20 mmol/L Hcy increased IL-8 production by 1.28 fold, 1.32 fold and 1.55 fold, respectively (P<0.01). IL-8 production were elevated significantly 3 h after treatment with 0.10 mmol/L Hcy. In addition, Hcy also increased IL-8 mRNA expression in a concentration-and time-dependent manner. CONCLUSION: Hcy may contribute to atherogenesis by inducing IL-8 expression and secretion in THP-1 macrophages.  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