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   210760篇
  免费   5349篇
  国内免费   472篇
耳鼻咽喉   2876篇
儿科学   8079篇
妇产科学   6349篇
基础医学   27215篇
口腔科学   6031篇
临床医学   17032篇
内科学   37904篇
皮肤病学   4780篇
神经病学   13429篇
特种医学   10853篇
外国民族医学   102篇
外科学   30798篇
综合类   1229篇
一般理论   69篇
预防医学   18899篇
眼科学   4537篇
药学   14508篇
  3篇
中国医学   177篇
肿瘤学   11711篇
  2021年   989篇
  2019年   807篇
  2018年   4314篇
  2017年   4432篇
  2016年   3736篇
  2015年   5479篇
  2014年   5071篇
  2013年   4433篇
  2012年   11238篇
  2011年   6124篇
  2010年   2919篇
  2009年   4428篇
  2008年   3029篇
  2007年   3813篇
  2006年   3855篇
  2005年   11893篇
  2004年   13288篇
  2003年   8809篇
  2002年   3876篇
  2001年   4390篇
  2000年   1745篇
  1999年   5888篇
  1992年   6894篇
  1991年   7123篇
  1990年   7357篇
  1989年   6967篇
  1988年   6474篇
  1987年   6247篇
  1986年   5972篇
  1985年   5261篇
  1984年   3606篇
  1983年   2916篇
  1982年   1015篇
  1981年   783篇
  1980年   850篇
  1979年   3834篇
  1978年   2369篇
  1977年   1794篇
  1976年   1569篇
  1975年   2483篇
  1974年   3115篇
  1973年   2745篇
  1972年   2762篇
  1971年   2747篇
  1970年   2561篇
  1969年   2469篇
  1968年   2241篇
  1967年   2167篇
  1966年   1903篇
  1965年   1135篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
The duodenal contents were examined in 81 patients with gastroduodenal ulcer. Bile acid concentrations, alkaline phosphatase activity, and sodium ion concentration were measured for the detection of duodenogastric reflux. Measurements of sodium ion concentration permitted estimation of the immediate volume of the duodenogastric reflux in the gastric contents. No methods for duodenogastric reflux detection should be given preference in examinations of peptic ulcer patients. Multiple-modality studies appear to be the most effective.  相似文献   
102.
103.
The interventional endoscopy and new knowledge about the spontaneous course of the cholelithiasis have obtained a far-reaching influence on the indication for operation and the surgical approach. Now as ever the adequate therapy of the symptomatic cholecystolithiasis consists in the early cholecystectomy. Since in the natural course the risk of lethality is small the operation for indication depending on the age and the risk factors given must be made cautiously. This in a still higher degree concerns the asymptomatic cholelithiasis in which at present no general indication for operation is regarded necessary. Due to the low lethality of circa 1% the endoscopic papillotomy has become the therapeutic method of choice in residual and recurrent calculi after cholecystectomy, but also in risk patients with cholecystocholedocholithiasis. The endoscopic papillotomy with stone extraction before the operation suggests a decrease of the operation lethality of 3 to 5% after cholecystectomy with revision of the choledochus.  相似文献   
104.
We studied the parathyroid function in patients with advanced renal failure by determining their plasma concentrations of ionized calcium (iCa), intact parathyroid hormone (PTH) and its inactive metabolites (PTH-MM). The suppressibility of the parathyroidism was studied with a calcium infusion test. The intact PTH values of the nondialysis and dialysis patients did not statistically differ from each other. The concentrations of PTH-MM were, however, higher in the dialysis patients than in the nondialysis patients (p less than 0.05). The ratio of PTH-MM to intact PTH was lowest in healthy reference subjects and highest in dialysis patients (p less than 0.01), and did not correlate with the degree of intact PTH elevation in the patient groups. The calcium infusion test was carried out on 15 patients. All showed suppression in the elevated plasma intact PTH concentration and in 6 the intact PTH value normalized. The PTH-MM value did not normalize in any of the patients. During oral calcium treatment the degree of intact PTH suppression at an achieved concentration of plasma iCa was predictable from the infusion test. Three patients were parathyroidectomized after the calcium infusion test. In 2 of these elevated intact PTH normalized within 24 h while in 1 no change took place. In this latter case on clinical improvement was noted. We conclude that the determination of plasma intact PTH concentration especially of combined with plasma iCa value is a reliable means of studying the hyperparathyroidism associated with chronic renal failure.  相似文献   
105.
To evaluate the relative contribution of insulin binding and postbinding defects of glucose utilization in peripheral tissue during normal and diabetic pregnancy, we have studied the in vitro insulin action of isolated adipocytes from eight nondiabetic pregnant women and nine pregnant women with insulin-dependent diabetes mellitus who were undergoing cesarian section. The pregnant women were compared with a matched group of normal nonpregnant women undergoing gynecologic surgery. Insulin binding to adipocytes measured at tracer insulin concentration was reduced by 45% (P less than 0.01) in normal pregnant women and by 30% (P less than 0.02) in pregnant women with diabetes. In contrast, no changes were found between the three groups in insulin binding to pure monocytes and erythrocytes. The glucose transport system in fat cells from both groups of pregnant women was characterized by impaired maximal (P less than 0.05) and half-maximal (P less than 0.05) response to insulin. When fat cell glucose metabolism was studied, pregnant diabetic women exhibited decreased basal lipogenesis (P less than 0.05) and decreased maximal responses of lipogenesis and glucose oxidation to insulin stimulation (P less than 0.05). Similar but less pronounced abnormalities were seen in glucose metabolism of adipocytes from nondiabetic pregnant women. In conclusion, both in late normal and diabetic pregnancy, insulin binding to adipocytes is significantly reduced and accompanied by decreased insulin sensitivity and reduced maximal insulin responsiveness of glucose transport and by impaired basal and maximally insulin-stimulated glucose metabolism.  相似文献   
106.
107.
108.
109.
110.
Thirty-one full-term newborn babies were investigated in order to establish reference values for ionized calcium. Only children fulfilling certain optimality criteria (with best possible maternal and infant conditions and uncomplicated pregnancy and delivery) were included. All infants were breast fed. Capillary blood for analysis of ionized calcium was collected by heel puncture on day 1 (6-36 h post partum, p.p.), day 3 (60-84 h p.p.) and day 5 (108-132 h p.p.). Ionized calcium was measured with a semi-automatic electrode system ICA 1 (Radiometer A/S, Copenhagen, Denmark). The reference ranges (mean +/- 2 SD) for days 1, 3 and 5 were 1.05-1.37, 1.10-1.42 and 1.20-1.48 mmol/l, respectively. The mean ionized calcium concentration on day 1 was significantly lower than on days 3 and 5. Reference values are also given for total calcium, magnesium and phosphate. We emphasize that it is impossible to calculate ionized calcium from total calcium or vice versa.  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