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   491806篇
  免费   6740篇
  国内免费   1790篇
电工技术   8393篇
综合类   2651篇
化学工业   72489篇
金属工艺   18756篇
机械仪表   14812篇
建筑科学   13695篇
矿业工程   1412篇
能源动力   12177篇
轻工业   47199篇
水利工程   4512篇
石油天然气   2174篇
武器工业   13篇
无线电   64276篇
一般工业技术   91814篇
冶金工业   77291篇
原子能技术   5818篇
自动化技术   62854篇
  2021年   2669篇
  2019年   2436篇
  2018年   17720篇
  2017年   16755篇
  2016年   13711篇
  2015年   3981篇
  2014年   5912篇
  2013年   19435篇
  2012年   13126篇
  2011年   23557篇
  2010年   19094篇
  2009年   18093篇
  2008年   20264篇
  2007年   21567篇
  2006年   12875篇
  2005年   13053篇
  2004年   12581篇
  2003年   12357篇
  2002年   11409篇
  2001年   11215篇
  2000年   10434篇
  1999年   10812篇
  1998年   24049篇
  1997年   17603篇
  1996年   13939篇
  1995年   10987篇
  1994年   9781篇
  1993年   9363篇
  1992年   7132篇
  1991年   6812篇
  1990年   6397篇
  1989年   6106篇
  1988年   5868篇
  1987年   4884篇
  1986年   4834篇
  1985年   5978篇
  1984年   5599篇
  1983年   4832篇
  1982年   4496篇
  1981年   4447篇
  1980年   4208篇
  1979年   4080篇
  1978年   3771篇
  1977年   4548篇
  1976年   6097篇
  1975年   3115篇
  1974年   3011篇
  1973年   2890篇
  1972年   2318篇
  1971年   2003篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
There are no firm epidemiologic data concerning psychiatric disorders associated with homicide recidivism. The authors studied all homicide recidivists who were incarcerated in Finnish prisons or high-security hospitals and had committed their last offense during the 3-year period July 1, 1988-June 30, 1991. All recidivists (13 subjects) could be considered to suffer from either severe alcoholism combined with personality disorder (N = 11, 85%) or from schizophrenia (N = 2, 15%).  相似文献   
992.
The shortage of suitable liver donors for children has motivated the use of ABO-incompatible (ABO-I) grafts for transplantation in urgent situations. However, survival after ABO-I liver grafts has been reported at about 30% as compared with 80% in cases of ABO-identical or -compatible liver grafts. This difference has been attributed to antibody-mediated, hyperacute or chronic liver rejection, due to preformed ABO antibodies (alloantibodies). In this study, we report our results with ABO-I livers in children without alloantibodies at the time of transplantation. From January 1988 to June 1993, 143 OLT were performed in 122 children. Eight children received 8 ABO-I liver grafts. Of these, 7 patients were included in the study. All 7 were alloantibody free before OLT. Five children were spontaneously alloantibody free, while in 2 children, the plasma alloantibodies were eliminated before and after transplantation using intravenous infusion of specific blood group antigens of the donor blood group (soluble antigens). Immunosuppression consisted of a triple-drug treatment combining CsA, AZA, and steroids. The follow-up period was between 10 and 48 months. One child died from a surgical complication. Six children survived, but 1 died 10 months later from intestinal obstruction. There were no graft losses and no episodes of hyperacute or chronic rejection. The graft and patient survival rate was 71%. There was a 28% incidence of rejection, but all were mild (requiring steroid boluses only). Our results suggest that the absence of ABO alloantibodies at the time of and after transplantation can protect ABO-I liver grafts against antibody-mediated rejection, whether hyperacute or chronic, and that soluble antigens are effective in eliminating alloantibodies in children.  相似文献   
993.
994.
The feasibility of using the murine monoclonal antibody, TP-1, for clinical immunoscintigraphy was examined in a pilot study involving 5 patients with bone sarcomas. 131I-labelled F(ab')2 antibody fragments were injected in doses of 0.8-1.0 mg (90-130 MBq), and the accumulation of radioactivity was examined by scintigraphy, and assessed by direct measurements on biopsied tumour and normal tissue. One osteosarcoma patient had a primary tumour in the femur, whereas the other 4 had single lung metastases detected by other diagnostic methods. Immunoscintigraphy of the femoral primary was optimally visualised after 22 h. In 2 patients, the method failed to detect lung metastasis, in 1 of the cases possibly related to less than optimal methodological conditions. In 2 other patients, increased accumulation of radioactivity indicated one and three lung tumours, in addition to the single metastasis observed by X-ray and CT scanning, tumours that were later confirmed and removed surgically. The concentration of radioactivity in tumour and normal tissues 44-72 h after antibody injection could be measured in 4 patients. The tumour to blood ratios were in the range of 1.2-4.2, compared to 0.1-0.8 for various normal tissues. The results indicate that immunoscintigraphy with TP-1 antibody fragments have a potential for early detection of lung metastases in patients with bone sarcoma.  相似文献   
995.
This paper reviews the pathogenesis of Mycobacterium bovis infection in cattle, focusing on aspects relating to the host rather than the organism. A broad concept of pathogenesis has been considered and information is presented on sources and routes of infection, as well as the immune responses and pathology. In addition, data is presented on the excretion of M. bovis from tuberculous cattle.  相似文献   
996.
997.
998.
999.
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