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   75252篇
  免费   3978篇
  国内免费   248篇
耳鼻咽喉   940篇
儿科学   4550篇
妇产科学   1391篇
基础医学   9100篇
口腔科学   1902篇
临床医学   5359篇
内科学   14559篇
皮肤病学   2017篇
神经病学   4368篇
特种医学   2009篇
外科学   10959篇
综合类   2548篇
一般理论   32篇
预防医学   3977篇
眼科学   3060篇
药学   7301篇
  2篇
中国医学   571篇
肿瘤学   4833篇
  2023年   524篇
  2022年   1551篇
  2021年   2682篇
  2020年   1466篇
  2019年   1758篇
  2018年   2319篇
  2017年   1640篇
  2016年   2164篇
  2015年   2239篇
  2014年   3217篇
  2013年   3921篇
  2012年   5483篇
  2011年   5449篇
  2010年   3194篇
  2009年   2670篇
  2008年   3879篇
  2007年   3909篇
  2006年   3759篇
  2005年   3141篇
  2004年   3062篇
  2003年   2591篇
  2002年   2180篇
  2001年   1580篇
  2000年   1545篇
  1999年   1295篇
  1998年   580篇
  1997年   438篇
  1996年   442篇
  1995年   410篇
  1994年   327篇
  1993年   288篇
  1992年   829篇
  1991年   726篇
  1990年   784篇
  1989年   706篇
  1988年   621篇
  1987年   588篇
  1986年   570篇
  1985年   543篇
  1984年   426篇
  1983年   337篇
  1982年   207篇
  1979年   335篇
  1978年   216篇
  1977年   258篇
  1975年   226篇
  1974年   236篇
  1973年   242篇
  1972年   219篇
  1971年   217篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
Eight healthy, young adult males underwent three separate, 10-min 70 degrees head-up tilts (HUT) over a period of nine days, in order to assess the intra- and inter-individual variability of cardiovascular and plasma norepinephrine (NE) responses to the manoeuvre. Cardiovascular parameters and plasma NE were measured in the basal state and at 2-min intervals during the HUT. The results indicate that: (1) the intra-individual variability is a smaller component of the total variability of both cardiovascular and plasma NE responses to HUT; (2) the variability in cardiovascular parameters is smaller than that in plasma NE levels, both basal and in response to postural stress; (3) there does not appear to be any difference in variability when expressed either as the maximal or the mean response to HUT; and (4) there does not appear to be an increase in the variability of the measured parameters over the duration of the HUT.  相似文献   
83.
The natural history of occult spinal dysraphism in children is one of progressive and unpredictable neurological deficit. The modern role of neurosurgery is in the prevention of deterioration rather than correction of established disability. A prospective study was carried out on 40 consecutive patients to analyse the referral pattern of children with this condition. The age, reason for referral, clinical history and source of referral was recorded in each case. The reason for referral varied with age. Of the 40 patients studied, only 12 were found to be without neurological deficit at the time of referral. The incidence of progressive neurological deterioration increased with increasing age. The referral source in different age groups varied, but in all age groups relatively few were referred by the general paediatricians or paediatric neurologists. For optimum surgical results, early referral and treatment is desirable and should become our objective.  相似文献   
84.
85.
Summary Data are presented on rates of admission for schizophrenia for the native born and the four largest foreign born populations living in England in 1981 (Irish, Indian, Pakistani and Caribbean born). These data show that, in general, the foreign born have higher rates of admission for schizophrenia, and a higher proportion of all diagnoses accounted for by this disorder than do the native born. The exception is Pakistani born women who have conspicuously low rates. Five hypotheses are examined to account for these differences. The apparently high rates of schizophrenia found for the Indian born of both sexes, and Pakistani born men can be accounted for to a large extent by the demographic differences that exist between them and the native born. The Irish born residents of England have rates comparable with the Irish in Ireland who also show much higher rates than do the native English. There is no completely satisfactory account for the very high rates found for Caribbean born men and women but a combination of adverse post migration experiences and tendency to misdiagnose schizophrenia in this group is offered as a tentative explanation for at least some of the excess. The low rates of admission for schizophrenia of Pakistani women is attributed to a tendency on their part to opt out of the formal mental health system after an initial encounter, possibly to return to their native land.  相似文献   
86.
87.
In the present study 108 full time workers employed in various sections of a railway workshop and exposed to smoke and irritant fumes, and 45 matched control subjects from local administrative staff were investigated to find prevalence of chronic bronchitis. In all 18 (16.7%) workers and 4 (8.9%) control subjects had clinical evidence of chronic bronchitis. Peak expiratory flow rate less than 300 L/min was observed in 54.6% workers and 2.2% control subjects. A significantly higher prevalence of chronic bronchitis was seen in workers. The advancing age, smoking and duration of exposure had significant influence on prevalence of chronic bronchitis.  相似文献   
88.
89.
A study of DNA content by flow cytometry revealed a significant difference between rhabdomyosarcomas, which were mainly non-diploid, and other sarcomas of children which were mainly diploid (p = 0.01). There was no association between DNA ploidy and survival or aggressive behaviour of the tumour as indicated for example by advanced clinical stage or unfavourable histology. While DNA ploidy correlated with age, it did not correlate with any other clinical characteristic. The apparent lack of prognostic value of DNA content may have been masked by some high CV values and overridden by the effect of chemotherapy which was the most significant variable in determining a patient's survival (p = 0.00005).  相似文献   
90.
The choice of a surgical approach for multi-level cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) is still a controversial issue. While most of the surgeons are still performing decompression by laminectomy some are doing multi-level anterior decompression. Few neurosurgeons are performing decompression by corpectomy. We have treated 26 patients by median cervical corpectomy during the last 4 years. These patients were followed up for a mean period of 25 months. Twenty one (80%) patients had a good outcome, 2 patients remained unchanged and 3 expired. Review of the literature and our experience indicates that patients with CSM and OPLL should be operated by median cervical corpectomy (anterior approach).  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