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   1486篇
  免费   71篇
  国内免费   1篇
耳鼻咽喉   27篇
儿科学   57篇
妇产科学   46篇
基础医学   131篇
口腔科学   56篇
临床医学   137篇
内科学   274篇
皮肤病学   86篇
神经病学   45篇
特种医学   35篇
外科学   218篇
综合类   137篇
一般理论   1篇
预防医学   102篇
眼科学   19篇
药学   165篇
肿瘤学   22篇
  2013年   11篇
  2010年   11篇
  2009年   15篇
  2001年   18篇
  2000年   10篇
  1999年   8篇
  1998年   21篇
  1997年   18篇
  1996年   40篇
  1995年   25篇
  1994年   24篇
  1993年   34篇
  1992年   24篇
  1991年   18篇
  1990年   23篇
  1989年   21篇
  1988年   25篇
  1987年   25篇
  1986年   21篇
  1985年   15篇
  1984年   13篇
  1983年   16篇
  1982年   10篇
  1981年   16篇
  1980年   21篇
  1979年   7篇
  1978年   12篇
  1977年   12篇
  1976年   15篇
  1975年   9篇
  1974年   11篇
  1972年   10篇
  1969年   8篇
  1968年   6篇
  1967年   6篇
  1965年   12篇
  1963年   17篇
  1962年   5篇
  1961年   7篇
  1960年   10篇
  1959年   98篇
  1958年   137篇
  1957年   115篇
  1956年   103篇
  1955年   117篇
  1954年   137篇
  1949年   67篇
  1948年   70篇
  1947年   10篇
  1946年   10篇
排序方式: 共有1558条查询结果,搜索用时 78 毫秒
41.
A radioimmunoassay was optimized to measure serum TSH with maximum sensitivity (sTSH). With this assay sTSH was less than 0.5 mIU/l in 100% of 64 patients with proven thyrotoxicosis and greater than 0.5 mIU/l in 92% of 76 normal subjects. sTSH correctly predicted the TSH response to TRH (delta TSH) in 93% of 125 patients with suspected thyrotoxicosis. In this group thyrotoxicosis was excluded by an sTSH greater than 0.5 mIU/l in 52% of patients thus avoiding the need for further testing.  相似文献   
42.
43.
Summary. Pregnancy-associated plasma protein-A (PAPP-A) and Schwangerschaftsprotein 1 (SP1) levels were measured in single serum samples from 60 patients admitted with vaginal bleeding in the first 14 weeks of pregnancy. When based on ultrasound diagnoses the prediction of non-viability (the predictive value) was 97% for SP1 and 84% for PAPP-A. Whereas the prediction of viability (above –2SD of the normal range) with SP1 was 88% the value with PAPP-A was only 57%; the poorer result obtained with PAPP-A probably reflects its longer half-life. Pregnancy outcome is not related to the duration of bleeding.  相似文献   
44.
Pharmacological doses of glucocorticoids inhibit TSH release both in vivo and in vitro and since the circadian rhythms of TSH and cortisol show a reciprocal relationship, the hypothesis has been advanced that changes in cortisol levels may be a primary determinant of circadian TSH changes. We have tested this hypothesis by studying the relationship between circadian cortisol and TSH rhythms in subjects before and during blockade with metyrapone. Seven patients were studied during their routine post-operative assessment following selective transethmoidal adenomectomy for microprolactinomas. PRL levels were restored to normal (less than 420 mU/l) in all patients by surgery (pre-op: 930-2752 mU/l, post-op: 33-376 mU/l) and the patients also had normal pituitary function in other respects. Blood was sampled hourly for 24 h before and on the third day of treatment with metyrapone (250 mg, 2 hourly). In order to compare circadian rhythms, hormonal data were subjected to cosinor analysis which involved fitting of the data with a cosine function using the method of least squares. The 6% cross reactivity of the cortisol antibody with 11-deoxycortisol was taken into account during the calculation of results. All subjects showed a normal cortisol rhythm which was strikingly blunted during metyrapone treatment. Group mean (+/- SD) TSH mesors, amplitudes and acrophases for control and metyrapone treated subjects were 1.5 +/- 0.26, 1.29 +/- 0.48; 0.46 +/- 0.26, 0.23 +/- 0.13 and -49 degrees +/- 9.8 degrees; -62 degrees +/- 2.7 degrees respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
45.
ABSTRACT. Four term healthy infants had their respiratory pattern monitored during a 2-hour afternoon nap recording period at monthly intervals up to six months of age. The time spent asleep significantly decreased with a marked reduction in active sleep (66% to 10%) while maintaining one long epoch of quiet sleep (mean 31 mins). Mean breathing rate at one week was higher in active sleep than quiet sleep (47 vs 41 breaths/min.) and decreased by 6 months in both sleep states (31 breaths/min. in both). Variability of breathing rate at 1 week was significantly increased in active sleep compared to quiet sleep and both decreased by 6 months. These findings confirm a significant maturational change in the respiratory pattern and variability of normal infants in the afternoon nap from 1 to 6 months.  相似文献   
46.
Alleged food-additive intolerance (respiratory, dermatological, behavioural or abdominal) was assessed in 19 children using daily challenge drinks of either, base product alone, base product plus sunset yellow/tartrazine, or base product plus sodium metabisulphite/sodium benzoate. The same type of drink was given for 12 days, double-blind and in random order. During the trial the children were maintained on an additive-free diet under supervision. Diary cards were used to record symptoms and medication usage. If there was an apparent association between symptoms and drink ingredient the trial was repeated, again double-blind. Additive intolerance was confirmed by a consistent deterioration of symptoms in only three children. In one, urticaria was induced by the colourings, in another extremely abnormal behaviour was induced by the preservatives and a third child was only free of asthma and abdominal pain on placebo. This form of individual trial, using 12 daily drinks, overcomes some of the objections to a single challenge study. Despite this, intolerance to the additives was only confirmed in 3/19 children in whom it had been believed to occur.  相似文献   
47.
Summary. A case is described in which thermoplasticized gutta-percha was successfully used to repair a buccal perforation caused by internal root resorption.  相似文献   
48.
49.
50.
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