首页 | 官方网站   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   24831篇
  免费   1263篇
  国内免费   58篇
医药卫生   26152篇
  2023年   270篇
  2022年   336篇
  2021年   654篇
  2020年   403篇
  2019年   481篇
  2018年   853篇
  2017年   720篇
  2016年   844篇
  2015年   724篇
  2014年   1054篇
  2013年   1392篇
  2012年   1513篇
  2011年   1648篇
  2010年   1074篇
  2009年   693篇
  2008年   837篇
  2007年   831篇
  2006年   807篇
  2005年   798篇
  2004年   799篇
  2003年   769篇
  2002年   775篇
  2001年   683篇
  2000年   614篇
  1999年   565篇
  1998年   186篇
  1997年   145篇
  1992年   297篇
  1991年   276篇
  1990年   270篇
  1989年   251篇
  1988年   238篇
  1987年   228篇
  1986年   236篇
  1985年   215篇
  1984年   170篇
  1983年   153篇
  1979年   211篇
  1978年   135篇
  1976年   120篇
  1975年   167篇
  1974年   186篇
  1973年   176篇
  1972年   166篇
  1971年   159篇
  1970年   181篇
  1969年   164篇
  1968年   186篇
  1967年   185篇
  1966年   146篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
A 4-year-old girl presented with an intramedullary epidermoid cyst of the cervical spinal cord. The clinical, radiological, and surgical features and a brief critical review of the literature are included in this report. The cyst contents were removed totally in two operations. The child had a coexisting neuroenteric cyst in the posterior mediastinum. To our knowledge, this coexistence has not been previously reported. Contemporary imaging modes and prospects of the surgical treatment are discussed.  相似文献   
42.
The authors describe the first three cases with a serologically confirmed hantaviral aetiology in the Czech Republic. It is the causal agent of haemorrhagic fever with renal syndrome, western type (strain CG 18-20, identical with the Puumala prototype). All patients come from a locality where since 1984 very actively a natural focus of hantaviral infection was investigated in small mammals, and where formerly groups of farmers were found with a high herd immunity with hantavirus. The disease was present in a mild to medium severe form with some sequelae. In the discussion the authors draw attention to the necessity of wider use of aetiological diagnosis in suspect diseases.  相似文献   
43.
Concentration and metabolic replacement (turnover) rate of glucose and ketone bodies were determined at intervals during a 52 day postweaning fast in five grey seal (Halichoerus grypus) pups, using bolus injections of radiotracers. Blood glucose was maintained at a high level throughout the fast, while beta-hydroxybutyrate increased 26 times from day 3 to day 37, whereafter it by and large was maintained. Glucose replacement rate decreased to 56% of the day 9 value at day 37 and dropped further to only 32% of the day 9 level at day 52 in two seals, while in another 2 seals it increased at this late stage. The average ketone body replacement rate ranged between 8.6 and 13.8 mumols min-1 kg-1, but did not change significantly (P greater than 0.05) during the fasting period. These results suggest a reduced gluconeogenesis from protein and increased production of ketone bodies, which may in part replace glucose as energy source during fasting.  相似文献   
44.
45.
46.
Antiepileptic drugs in schizophrenia: a review.   总被引:2,自引:0,他引:2  
The first choice group of psychotropic agents in schizophrenia is neuroleptics. However, this treatment is not effective in all patients and with every symptom. We summarize papers published on the role of antiepileptic drugs in treatment-resistant schizophrenia. We have searched the computer database system MEDLINE for relevant articles including reviews, reports of drug studies and case histories. Antiepileptic drugs can change symptoms of schizophrenia by their action on GABA-ergic neurotransmission or via anti-glutamatergic mechanisms. High doses of adjunctive benzodiazepines reduce positive symptoms, anxiety, and agitation. Carbamazepine is effective in affective symptoms of schizophrenia and influences violent behavior in psychotic patients. Its anti-kindling action may represent a promising treatment strategy for some patients with chronic course of schizophrenia. Valproate treatment leads to a decrease in positive symptoms as well as hostility. Lamotrigine is expected to influence the positive, negative, affective, and cognitive symptoms of schizophrenia. New antiepileptics (e.g., gabapentin, oxcarbazepine, topiramate, vigabatrin) present a promise as potential adjuncts to neuroleptic treatment in resistant symptoms of schizophrenia.  相似文献   
47.
48.
A group of 54 patients with the original diagnosis of polycythemia vera were subjected to cytogenetic examination. Six (17.6%) of the 34 cases examined in the period of the advanced phase of the polycythemia vera had a chromosomal change. Thirteen (65%) of the 20 patients undergoing the cytogenetic examination in the period when the polycythemia vera turned into another myeloproliferative disease showed chromosomal aberration. This suggests a relationship between the number of chromosomal changes and the transformation of the disease. No connection between the cytogenetic changes and myelosuppressive cures could be confirmed in our material. The chromosomal change 20q- considered to be the most frequent kind in the polycythemia vera was not discovered until in patients with the polycythemia vera transformed into a different myeloproliferative disease.  相似文献   
49.
The autolyzed antigen-extracted allogeneic (AAA) bone implant was placed into a 17-mm long diaphyseal periosteum-free defect in the radius in 27 rabbits. The animals were observed physically and roentgenologically every week. The continuity of the radius was evaluated macroscopically and histologically. Maximum length of the follow-up period was 114 days. The AAA implants were progressively resorbed and replaced by the recipient's bone growing from fragments of radius, restoring the continuity of diaphysis. Osteoinductive activity of the implant was transferred across a tube of a polyamide vascular prosthesis. There were no appreciable histologic signs or immune of foreign-body reaction.  相似文献   
50.
Gastric teratoma is a very rare benign tumor. Fifty-three cases, only two of which were females, have previously been reported. This report concerns two cases of teratoma arising from stomach. One of them is the third female case described in the literature.  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-23

京公网安备 11010802026262号