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   2381284篇
  免费   195416篇
  国内免费   4239篇
耳鼻咽喉   34329篇
儿科学   72939篇
妇产科学   63080篇
基础医学   336022篇
口腔科学   67704篇
临床医学   216257篇
内科学   469941篇
皮肤病学   48066篇
神经病学   201341篇
特种医学   96208篇
外国民族医学   887篇
外科学   361396篇
综合类   56240篇
现状与发展   1篇
一般理论   979篇
预防医学   190959篇
眼科学   55532篇
药学   177959篇
  4篇
中国医学   4384篇
肿瘤学   126711篇
  2018年   24279篇
  2016年   20663篇
  2015年   23407篇
  2014年   33732篇
  2013年   51112篇
  2012年   69063篇
  2011年   72628篇
  2010年   42695篇
  2009年   41131篇
  2008年   69044篇
  2007年   73412篇
  2006年   74272篇
  2005年   72325篇
  2004年   69597篇
  2003年   67304篇
  2002年   66533篇
  2001年   112627篇
  2000年   116669篇
  1999年   98512篇
  1998年   28008篇
  1997年   25662篇
  1996年   25546篇
  1995年   24682篇
  1994年   23254篇
  1993年   21632篇
  1992年   79474篇
  1991年   76465篇
  1990年   73636篇
  1989年   70904篇
  1988年   65910篇
  1987年   64860篇
  1986年   61386篇
  1985年   58449篇
  1984年   44257篇
  1983年   37696篇
  1982年   22913篇
  1981年   20364篇
  1980年   19075篇
  1979年   41347篇
  1978年   29027篇
  1977年   24386篇
  1976年   22860篇
  1975年   23996篇
  1974年   29672篇
  1973年   28070篇
  1972年   26263篇
  1971年   24199篇
  1970年   22773篇
  1969年   21121篇
  1968年   19149篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
The value of maternal C-reactive protein (CRP) levels as predictors of fetal and maternal infective morbidity and fetal mortality was assessed prospectively over a 6-month period in all cases of premature rupture of the fetal membranes or suspected premature labour. Statistical analysis of results showed that CRP at a level of 1.32 mg/dl is a sensitive marker of infective morbidity in mother and neonate. Furthermore, there was a significant association between raised CRP levels and low-birth-weight babies, suggesting that intra-uterine infection is a major cause of prematurity in the study population.  相似文献   
972.
The second documented case of renal aspergilloma due to Aspergillusflavus is presented. The merits of the medical therapy thatfailed are discussed. Pathological examination showed a nidusof aspergillus around suture material persisting from a pyelolithotomyoperation 2 years before in India. We argue that this was thereason for the failure of the medical therapy. This is the firstcase of its kind reported.  相似文献   
973.
A study of intravenous (i.v.) cannula usage for medical emergencies admitted to hospitals in the Newham Health District was undertaken during two defined periods (24 and 35 days). Almost half the cannulas inserted (47%) were not flushed following an initial bolus injection of heparinized saline. The duration that cannulas remained in a vein ranged from 24 hours to 8 days (median 2 days) and inflammation around the cannula site was related to the length of time since insertion but unrelated to whether the cannula was flushed regularly or to the type of fluid used. Our findings indicate a substantial wastage of i.v. cannulas due to difficulties with insertion and suggest that isotonic saline, without heparin, is effective in maintaining cannula patency for 48 hours. It is concluded that these findings are not unique to the Newham Health District and worthwhile financial savings should be achieved throughout the NHS if clinicians reconsider the indications and use of i.v. cannulas for their patients.  相似文献   
974.
975.
Effects of iontophoretically applied dopamine and its receptor antagonists on physiologically identified retinal ganglion cells were studied in the optically intact eye of pentobarbitone anaesthetised kittens (7-9 weeks of age) and the results were compared with the effects obtained from adult cats (18-22 weeks of age). In both the adult and the kitten, dopamine had an inhibitory effect on visually evoked and spontaneous activity of the retinal ganglion cells, irrespective of cell type. However, unlike in the adult, the effects of dopamine in kittens were variable and not dependent on retinal eccentricity. In adult cells, only L-sulpiride (a potent D2 receptor antagonist) reduced the inhibitory effect of exogenous dopamine, whereas in kitten cells, both alpha-flupenthixol (a potent D1 receptor antagonist) and L-sulpiride did so. When applied alone, neither alpha-flupenthixol nor affected the activity of ganglion cells in adults, but in kittens both antagonists produced an excitatory effect in some cells. Physiologically active dopaminergic innervation seemed, therefore, to be present on the immature ganglion cells, but was subsequently 'eliminated' during the course of postnatal development. Furthermore, in immature cells, both D1 and D2 type receptors are present but only D2 receptors remain in adult. Therefore, there is a mismatch between dopamine receptors and dopamine in the adult retina and this mismatch may be the consequence of a developmental event.  相似文献   
976.
Two hundred and thirty pregnancies were studied in 196 diabetic women. Seven women with babies found to have major malformations had a higher median first trimester haemoglobin A1 (12.9%) than the median HbA1 (10.8%) in those with normal babies (p = 0.06). No relationship was found between the occurrence of minor malformations and first trimester maternal haemoglobin A1. Two of the seven congenital malformations were diagnosed antenatally at a time when therapeutic abortion could be offered. Expert antenatal ultrasound scanning should be offered to all pregnant diabetic women as poor glycaemic control at the time of conception and organogenesis, as evidenced by raised first trimester HbA1, predisposes to congenital malformation.  相似文献   
977.
Various cases are presented demonstrating the role of computed tomography (CT) in the assessment of serosal and bowel wall pathology. Reference is made to the morphology of the lesions. Illustrative examples of tumors, secondary malignant dissemination, irradiation injury to the gut, and intramural gas associated with ulcerative colitis, are all illustrated.  相似文献   
978.
979.
980.
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