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   2447篇
  免费   84篇
  国内免费   10篇
耳鼻咽喉   13篇
儿科学   62篇
妇产科学   32篇
基础医学   682篇
口腔科学   8篇
临床医学   274篇
内科学   495篇
皮肤病学   23篇
神经病学   189篇
特种医学   43篇
外科学   142篇
综合类   4篇
现状与发展   1篇
一般理论   2篇
预防医学   129篇
眼科学   29篇
药学   239篇
中国医学   5篇
肿瘤学   169篇
  2023年   51篇
  2022年   99篇
  2021年   146篇
  2020年   52篇
  2019年   76篇
  2018年   67篇
  2017年   37篇
  2016年   53篇
  2015年   71篇
  2014年   59篇
  2013年   78篇
  2012年   105篇
  2011年   117篇
  2010年   70篇
  2009年   54篇
  2008年   88篇
  2007年   104篇
  2006年   104篇
  2005年   105篇
  2004年   78篇
  2003年   57篇
  2002年   39篇
  2001年   14篇
  2000年   15篇
  1999年   30篇
  1998年   18篇
  1992年   26篇
  1991年   42篇
  1990年   35篇
  1989年   39篇
  1988年   34篇
  1987年   37篇
  1986年   30篇
  1985年   37篇
  1984年   28篇
  1983年   28篇
  1979年   27篇
  1978年   16篇
  1977年   20篇
  1976年   13篇
  1975年   23篇
  1974年   32篇
  1973年   25篇
  1972年   31篇
  1971年   33篇
  1970年   18篇
  1969年   18篇
  1968年   23篇
  1967年   16篇
  1966年   18篇
排序方式: 共有2541条查询结果,搜索用时 15 毫秒
51.
This study presents findings on the biological action of an integrated supplement containing the following components involved in osteogenesis and mineralization: vitamin D and silicon in the bioavailable and soluble form. A hypothesis that these components potentiate one another’s action and make calcium absorption by the body more efficient was tested. Biological tests of the effect of vitamin D and silicon chelates on bone fracture healing and bone turnover were conducted using ICR mice and albino Wistar rats. Radiographic and biochemical studies show that the supplement simultaneously containing silicon chelates and vitamin D stimulates bone tissue regeneration upon mechanical defects and accelerates differentiation of osteogenic cells, regeneration of spongy and compact bones, and restoration of bone structure due to activation of osteoblast performance. Bone structure restoration was accompanied by less damage to skeletal bones, apparently due to better absorption of calcium from food. The studied supplement has a similar effect when used to manage physiologically induced decalcification, thus holding potential for the treatment of osteomalacia during pregnancy or occupational diseases (e.g., for managing bone decalcification in astronauts).  相似文献   
52.
53.
54.
We studied the epidemiology of drug-resistant tuberculosis (TB) in Vladimir Region, Russia, in 2012. Most cases of multidrug-resistant TB (MDR TB) were caused by transmission of drug-resistant strains, and >33% were in patients referred for testing after mass radiographic screening. Early diagnosis of drug resistance is essential for preventing transmission of MDR TB.  相似文献   
55.
The objectives of this work were (i) to characterize the pharmacokinetics of cefazolin in pregnant women undergoing elective cesarean delivery and in their neonates; (ii) to assess cefazolin transplacental transmission; (iii) to evaluate the dosing and timing of preoperative, prophylactic administration of cefazolin to pregnant women; and (iv) to investigate the impact of maternal dosing on therapeutic duration and exposure in newborns. Twenty women received 1 g of cefazolin preoperatively. Plasma concentrations of total cefazolin were analyzed from maternal blood samples taken before, during, and after delivery; umbilical cord blood samples obtained at delivery; and neonatal blood samples collected 24 h after birth. The distribution volume of cefazolin was 9.44 liters/h. The values for pre- and postdelivery clearance were 7.18 and 4.12 liters/h, respectively. Computer simulations revealed that the probability of maintaining free cefazolin concentrations in plasma above 8 mg/liter during scheduled caesarean surgery was <50% in the cord blood when cefazolin was administered in doses of <2 g or when it was administered <1 h before delivery. Therapeutic concentrations of cefazolin persisted in neonates >5 h after birth. Cefazolin clearance increases during pregnancy, and larger doses are recommended for surgical prophylaxis in pregnant women to obtain the same antibacterial effect as in nonpregnant patients. Cefazolin has a longer half-life in neonates than in adults. Maternal administration of up to 2 g of cefazolin is effective and produces exposure within clinically approved limits in neonates.  相似文献   
56.
57.
58.
The plasma aldosterone (A) and desoxycorticosterone (DOCS) levels were measured in 10 patients with primary aldosteronism and in 2 subgroups with low-renin hypertensive disease (LRHD): (1) those with normal adrenal glands++ (n - 11) and (2) those with structural changes in the cortex (n - 11). The patients from Subgroup 1 showed the lowest basal A and DOCS levels (107.29 +/- 12.90 and 0.080 +/- 0.013 ng/ml, respectively) and low concentrations of the two hormones after stimulation of 4-hour walk (211.57 +/- 30.47 and 0.095 +/- 0.024 ng/mg, respectively). In the patients from Subgroup 2, the basal and 4-hour post-walk++ A and DOCS contents were increased in the cortex (basal 201.50 +/- 41.59 and 0.177 +/- 0.36 ng/mg and poststimulation 331.33 +/- 30.47 and 0.302 +/- 0.061 ng/ml, respectively). Some patients with primary aldosteronism displayed the same DOCS response to stimulation as did those with LRHD in the presence of structural cortical changes. Histological examination of operative biopsy specimens indicated that higher DOCS levels were associated with diffuse nodal hyperplasia of the zona fasciculata in the cortex. The results suggest that there may be a LRHD variant running with excessive DOCS secretion and related to pathogenetically related to hyperplasia of predominantly the zone fasciculata in the adrenal cortex.  相似文献   
59.
High density of the rat population in Moscow in 1990-1991 resulted in the appearance of Ornithonyssus bacoti foci and of cases of the rat-mite dermatitis in humans. A total of 36 foci of the disease were examined and eradicated. A method for the detection of such foci has been developed. Two types of foci are distinguished, communal and industrial, and their specific features as regards the rodent and mite populations and clinical features of dermatitis in humans are described. A system of measures for liquidation of foci of rat mites is suggested, including rat and mite eradication and treatment of the patients. Specific features of these measures for various types of foci and in case of a focus reappearance are enumerated.  相似文献   
60.
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