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   1104篇
  免费   3篇
  国内免费   1篇
电工技术   1篇
化学工业   13篇
金属工艺   2篇
机械仪表   1篇
建筑科学   6篇
能源动力   1篇
轻工业   6篇
水利工程   1篇
无线电   8篇
一般工业技术   10篇
冶金工业   1020篇
原子能技术   2篇
自动化技术   37篇
  2023年   2篇
  2022年   1篇
  2020年   1篇
  2019年   1篇
  2018年   1篇
  2016年   1篇
  2015年   2篇
  2014年   2篇
  2013年   4篇
  2012年   5篇
  2011年   13篇
  2010年   9篇
  2009年   8篇
  2008年   10篇
  2007年   3篇
  2006年   1篇
  2005年   3篇
  2004年   1篇
  2003年   4篇
  2002年   3篇
  2001年   5篇
  2000年   2篇
  1999年   32篇
  1998年   316篇
  1997年   208篇
  1996年   118篇
  1995年   67篇
  1994年   47篇
  1993年   68篇
  1992年   6篇
  1991年   6篇
  1990年   12篇
  1989年   9篇
  1988年   8篇
  1987年   15篇
  1986年   9篇
  1985年   8篇
  1983年   1篇
  1982年   2篇
  1981年   7篇
  1980年   7篇
  1978年   3篇
  1977年   22篇
  1976年   52篇
  1974年   1篇
  1973年   1篇
  1955年   1篇
排序方式: 共有1108条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
Drugs in salmonid aquaculture--a review   总被引:2,自引:0,他引:2  
In contrast to mammalian therapeutics, the use of pharmaceutical substances is rather limited in fish. It is basically restricted to anaesthetic agents and anti-infective agents for parasitic and microbial diseases. Anaesthetic agents are used primarily in fish farm and laboratory settings to provide analgesia and immobilization of fish for minor procedures. The anti-infective agents are used for controlling diseases and the choice of drug depends on efficacy, ease of application, human safety, target animal safety including stress to the fish, environmental impact, regulatory approval, costs, and implications for marketing the fish. In this article, the major drugs used in salmonids in North America and Europe will be reviewed and some insight into future directions for drug development and use for the salmonid industry will be introduced. The mechanisms of action, pharmacokinetics, side effects, and uses of the drugs are emphasized.  相似文献   
995.
Exploration of the indole nitrogen region of Zafirlukast (1) has uncovered a potent series of cysteinyl leukotriene D4 (LTD4) antagonists. These studies showed that a variety of functionality could be incorporated in this region of the molecule without sacrificing potency. Efforts to exploit this site in order to improve oral efficacy are discussed.  相似文献   
996.
Suicidal adolescents represent a uniquely demanding clinical population. Regardless of psychotherapeutic orientation, the existing standards of care demand a relatively broad and integrative approach with multiple and specific treatment targets, as well as ongoing and repeated risk assessment. The current article provides an integrative conceptual framework for these tasks in day to day clinical practice with essentially two goals: (1) to provide a summary of therapeutic and assessment tasks (i.e. the content of therapy and assessment) consistent with existing standards of care and supported by empirical findings, and (2) to emphasize the varied roles, tasks, demands and limitations of psychotherapy with suicidal adolescents.  相似文献   
997.
BACKGROUND: Host macrophages are abundant within fetal pig pancreas xenografts undergoing rejection, but their role is unknown. Therefore, we examined the effect of host macrophage depletion on xenograft rejection. METHODS: Nonobese diabetic (NOD) mice were given clodronate-loaded liposomes intravenously to deplete macrophages. Controls received phosphate-buffered saline (PBS) or PBS-liposomes. General immune status was assessed after 2, 3, and 7 days by (1) fluorescence-activated cell sorter analysis of peripheral blood, spleen, and lymph node cells, (2) immunohistochemistry on spleens, and (3) mixed lymphocyte reaction. Organ-cultured fetal pig pancreas was transplanted under the kidney capsule of NOD mice 3 days after clodronate or PBS injection. Grafts were assessed histologically at 4, 5, 6, and 8 days after transplantation. RESULTS: Splenic macrophages and peripheral blood monocytes were depleted 2 days after clodronate treatment but had recovered within 11 days. T cell, B cell, and dendritic cell numbers were normal in spleen, peripheral blood, and lymph nodes of clodronate-treated mice, and T cells and antigen-presenting cells from these mice functioned normally in mixed lymphocyte reaction. Clodronate treatment markedly reduced graft infiltration by macrophages, T cells, and eosinophils at 4, 5, and 6 days after transplantation, and was associated with maintenance of endocrine cell viability and insulin expression. However, all grafts were rejected 8 days after transplantation, concordant with reappearance of splenic macrophages. CONCLUSIONS: Short-term, specific depletion of macrophages markedly delayed cellular infiltration and rejection of xenografts. The results provide the first evidence that macrophages promote T-cell infiltration and rejection of fetal pig pancreas xenografts in NOD mice.  相似文献   
998.
999.
Cancer pain theoretically comprises sensory, affective, and cognitive dimensions, implying that patients and family members perceive and report cancer pain based on these factors. The study reported here investigated the relationship between specific knowledge and attitudes (cognitive factors), and patients' and family members' reports of pain due to cancer. The relationship between cognitive factors and reports of cancer pain was investigated in interviews with 122 patients and their family members. Pain was measured using the Brief Pain Inventory; knowledge and attitudes were measured using a form previously developed by the authors. Patients' and family members' reports of patient pain and performance status were highly correlated, although family members consistently reported more pain and disability. Using regression analysis, cognitive factors were strongly related to family reports of patients' pain (R2 = 0.27), but contributed little to explaining pain reported by patients themselves (R2 = 0.06). Improved understanding of patients' pain assessments depends on further investigation of other cognitive factors and of sensory and affective factors. Family members' assessments of pain are significantly related to appropriate knowledge and attitudes.  相似文献   
1000.
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