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   1039951篇
  免费   73910篇
  国内免费   1540篇
耳鼻咽喉   14003篇
儿科学   27451篇
妇产科学   25569篇
基础医学   149611篇
口腔科学   31246篇
临床医学   89733篇
内科学   204584篇
皮肤病学   21110篇
神经病学   82820篇
特种医学   41149篇
外国民族医学   88篇
外科学   165554篇
综合类   18515篇
现状与发展   2篇
一般理论   334篇
预防医学   74375篇
眼科学   22910篇
药学   78999篇
  3篇
中国医学   2359篇
肿瘤学   64986篇
  2019年   7741篇
  2018年   11178篇
  2017年   8899篇
  2016年   9822篇
  2015年   11181篇
  2014年   15181篇
  2013年   21635篇
  2012年   30492篇
  2011年   31432篇
  2010年   18175篇
  2009年   17767篇
  2008年   30292篇
  2007年   31578篇
  2006年   32148篇
  2005年   30742篇
  2004年   29081篇
  2003年   27878篇
  2002年   27112篇
  2001年   58219篇
  2000年   60018篇
  1999年   50077篇
  1998年   12087篇
  1997年   10574篇
  1996年   10779篇
  1995年   9887篇
  1994年   9166篇
  1993年   8418篇
  1992年   37766篇
  1991年   35963篇
  1990年   34646篇
  1989年   33655篇
  1988年   30650篇
  1987年   29683篇
  1986年   27675篇
  1985年   26470篇
  1984年   18794篇
  1983年   15994篇
  1982年   8248篇
  1979年   16549篇
  1978年   11074篇
  1977年   9451篇
  1976年   8171篇
  1975年   8946篇
  1974年   10856篇
  1973年   10236篇
  1972年   9699篇
  1971年   9184篇
  1970年   8688篇
  1969年   8174篇
  1968年   7478篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
10 patients with CLL and 2 with CML were treated with gradually increasing doses of 1 alpha(OH)D3, up to 4 micrograms daily during 6 wk. 3 patients with preleukemia and 1 with myelofibrosis were treated with 2 micrograms daily of 1 alpha(OH)D3 for a prolonged period up to 17 wk. The treatment with 1 alpha (OH)D3 did not result in changes of disease parameters in any of the patients under study. Receptor studies for 1,25(OH)2D3 were performed in 8 CLL patients and revealed only 1 patient with increased specific receptor binding capacity. The maximum tolerable dose of 1 alpha(OH)D3 varied individually, but was in the range of 2-4 micrograms daily.  相似文献   
122.
123.
IgG-maleimide peroxidase, Fab'-maleimide peroxidase, polymer and monomer types of Fab'-periodate peroxidase were prepared from an antibody against rat lipoamide dehydrogenase, a component of the pyruvate dehydrogenase complex which is located in mitochondria. They were examined for immunohistochemical staining of the rat kidney. Fab'-maleimide peroxidase was the best for staining mitochondrial protein. IgG-maleimide peroxidase and the monomer type of Fab'-periodate peroxidase had the same intensity of staining. The polymer type of Fab'-periodate peroxidase could not stain the lipoamide dehydrogenase.  相似文献   
124.
125.
126.
127.
The effects of two promoters of hepatocarcinogenesis--phenobarbital and butylated hydroxytoluene (BHT)--on five hepatic biochemical parameters were examined in adult female rats. Phenobarbital given orally in two doses each of 110 mg/kg 21 and 4 hr before the rats were killed caused large increases in hepatic ornithine decarboxylase (ODC) activity and cytochrome P-450 content. Extending the number of phenobarbital treatments to five increased the hepatic enzyme induction and also caused a minor decrease in hepatic glutathione and a small increase in serum alanine aminotransferase activity. Two oral doses of 700 mg BHT/kg (20% of the LD50) caused hepatic DNA damage and induction of both ODC activity and cytochrome P-450 content. When the dose of BHT was reduced from 700 to 140 mg/kg no significant effects on the biochemical parameters were found. Both promoters of hepatocarcinogenesis were identified by their induction of ODC, a marker for promotional potential, but only BHT showed a potential for carcinogenic initiation. The biochemical parameters examined, particularly the alkaline elution technique for DNA damage, ornithine decarboxylase activity and serum alanine aminotransferase, may constitute a useful assay system for examining a compound's potential for carcinogenic initiation, carcinogenic promotion and cellular toxicity.  相似文献   
128.
The simultaneous determination of cerebrospinal fluid (CSF) and plasma adenosine deaminase (ADA) activity was evaluated as a diagnostic aid in tuberculous meningitis (TBM). CSF and plasma ADA activity were determined in four groups of patients: (i) a 'no meningitis' group of 174 children investigated for possible meningitis, but found to be uninfected; (ii) an aseptic meningitis group of 40 children; (iii) a bacterial meningitis group of 31 children; and (iv) a TBM group of 27 patients (24 children and 3 adults). CSF ADA alone was determined in a further 23 children with aseptic meningitis, 19 with bacterial meningitis and 13 children and 7 adults with TBM. Both the CSF/plasma ADA ratio and the absolute CSF ADA activity were raised in TBM (mean values 0,24 and 12,61 U/I respectively) and bacterial meningitis (mean values 0,59 and 15,43 U/I respectively), but not in the aseptic meningitis group (mean values 0,06 and 2,00 U/I) or the 'no meningitis' group (mean values 0,04 and 1,51 U/I). Both values will distinguish TBM from aseptic meningitis, but do not appear to hold any marked advantages over conventional CSF criteria in the diagnosis of TBM.  相似文献   
129.
130.
In a four month period 228 patients were admitted to the Wakari assessment and rehabilitation unit in Dunedin, New Zealand. One hundred and seventy subjects came from the community, 35 were transferred from the local public hospital, and 23 were readmitted. Median lengths of stay were 13, 26 and 10 days respectively. Assessment of activities of daily living (ADL) dependency on admission and discharge showed a significant improvement in ability by discharge, which correlated closely with place to which subjects were discharged, and with survival. There was 5% inpatients death rate which cumulated to 18%, 23%, 34%, 39% and 46% by six weeks, three months, six months, nine months and one year respectively. High discharge dependency was closely related to poor survival after discharge. Use of domiciliary services did not change because the savings from those who moved into institutions were cancelled out by those who were discharged back to the community being in need of increased social support.  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