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   20652篇
  免费   1849篇
  国内免费   32篇
耳鼻咽喉   219篇
儿科学   589篇
妇产科学   493篇
基础医学   2613篇
口腔科学   433篇
临床医学   2469篇
内科学   3673篇
皮肤病学   219篇
神经病学   2061篇
特种医学   538篇
外科学   2622篇
综合类   591篇
一般理论   27篇
预防医学   2295篇
眼科学   472篇
药学   1579篇
中国医学   16篇
肿瘤学   1624篇
  2022年   143篇
  2021年   289篇
  2020年   200篇
  2019年   284篇
  2018年   356篇
  2017年   278篇
  2016年   319篇
  2015年   349篇
  2014年   453篇
  2013年   718篇
  2012年   1067篇
  2011年   1053篇
  2010年   578篇
  2009年   523篇
  2008年   969篇
  2007年   1041篇
  2006年   959篇
  2005年   938篇
  2004年   944篇
  2003年   856篇
  2002年   861篇
  2001年   630篇
  2000年   578篇
  1999年   519篇
  1998年   268篇
  1997年   205篇
  1996年   225篇
  1995年   207篇
  1994年   187篇
  1993年   184篇
  1992年   396篇
  1991年   387篇
  1990年   420篇
  1989年   378篇
  1988年   365篇
  1987年   357篇
  1986年   346篇
  1985年   310篇
  1984年   244篇
  1983年   202篇
  1982年   139篇
  1981年   124篇
  1979年   238篇
  1978年   159篇
  1977年   135篇
  1976年   122篇
  1975年   144篇
  1974年   166篇
  1973年   131篇
  1968年   118篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
BACKGROUND AND PURPOSE: Although indomethacin has been demonstrated to prevent germinal matrix and intraventricular hemorrhage in clinical and animal studies, the mechanism of action of this agent to prevent hemorrhage remains unclear. Previous studies have demonstrated both that the microvessels in the germinal matrix of newborn beagle pups undergo basement membrane maturation during the first 4 postnatal days and that indomethacin may promote laminin deposition in tumor cell culture systems. METHODS: We employed the newborn beagle pup model to test the hypothesis that indomethacin may stimulate laminin deposition in germinal matrix microvessels. Newborn pups were randomized to receive either 0.1 mg/kg/dose i.p. indomethacin or an equal volume of saline diluent. Pups received doses of study medication once a day for 1, 2, or 3 days and were studied on postnatal days 1, 2, 3, or 4. Pups were anesthetized and systemically perfused with buffered formalin; the brains were removed and prepared for immunohistochemical study. RESULTS: Sections stained with Bandeiraea lectin demonstrated that there was no difference in germinal matrix vessel density among the postnatal ages studied; similarly, there were no differences in vessel density between saline- and indomethacin-treated animals at any postnatal age. Quantification of germinal matrix stained intensity by confocal microscopy demonstrated significant increases in indomethacin-treated pups for both laminin staining at postnatal days 2 (p = 0.05) and 3 (p = 0.0009) and type V collagen staining at postnatal day 2 (p = 0.011). Although staining for beta 1 integrins increased across postnatal ages, there were no differences between saline- and indomethacin-treated animals. CONCLUSIONS: These data suggest that indomethacin may stimulate basement membrane deposition in the germinal matrix microvessels of newborn beagle pups to prevent germinal matrix and/or intraventricular hemorrhage.  相似文献   
93.
We studied the effect of postoperative administration of subconjunctival 5-fluorouracil in maintaining postoperative filtration following combined trabeculectomy and extracapsular cataract extraction with posterior chamber lens implantation. Three months postoperatively, the mean intraocular pressure in 15 patients who had received 5-fluorouracil was 13.1 +/- 3.2 mm Hg; in 17 control patients, it was 13.0 +/- 3.0 mm Hg (P greater than .05). The mean number of postoperative medicines in the study patients was 0.7; in the control patients, 0.8 (P greater than .05). Bleb appearance and improvement in visual acuity were similar in the two groups. This study does not support the routine use of 5-fluorouracil in patients who have undergone combined trabeculectomy and extracapsular cataract extraction.  相似文献   
94.
The internal mammary artery is currently the arterial replacement of choice for coronary artery bypass grafts. The authors studied the permeability of the vessel wall of the internal mammary artery and the ascending aorta in 12 patients undergoing coronary artery bypass grafts by comparing the 125I-albumin binding profiles. Their results suggest that albumin crosses the internal mammary artery more easily than in the aorta.  相似文献   
95.
A modified end-point enzymatic method for the measurement of ammonia in stool water is presented. A protein precipitation step was included in order to inactivate urease and faecal enzymes, which oxidise NADH. The modified method is reliable, with acceptable precision and accuracy, and is linear up to a concentration of 1.5 mmol/l.  相似文献   
96.
The duration of retention of tolerance to ethanol was tested in the alcohol-preferring (P) and alcohol-nonpreferring (NP) rats lines, using ethanol-induced hypothermia as a measure of tolerance. Rats received two injections of ethanol (3.5 g/kg) body wt, IP) and the time between the injections was 1, 2, or 3 days. When one day separated the two injections, tolerance to the hypothermic effect of a second “test” injection was found in both lines. When 2 or 3 days separated the two injections, the P line showed a loss of tolerance and the NP line showed sensitization to ethanol. Sensitization in the NP line grew stronger when the interval between injections was increased from 2 to 3 days. The duration of retention of tolerance to ethanol-induced hypothermia in the P line was shorter than has previously been reported for motor impairment in this line. It appears that the duration of tolerance retention in the P line depends on the test used to measure tolerance. Sensitization to ethanol in the NP line may be associated with low oral ethanol intake. This research was supported, in part, by grants AA08312, AA03243, and AA07611 from the PHS  相似文献   
97.
98.
BACKGROUND: Nurse leaders in Fiji are currently involved in meeting the challenges of being at the forefront of an AusAID supported Health Sector Improvement process. Fiji is experiencing the same shortages of health professionals (including nurses) as is occurring internationally, while simultaneously striving to improve the quality of its health services. PRIMARY ARGUMENT: This paper provides information about the current situation in relation to health services in Fiji, and describes strategies being undertaken by the nurse leaders of Fiji to meet the challenge of leading an exciting reform process. James Cook University, School of Nursing Sciences, has been privileged to support the provision of contemporary leadership and management education for current and future nurse leaders in the Fiji Health Sector as a component of a current education program to educate registered nurses to bachelor level. This paper will provide an overview of the current Fiji Health Sector Improvement Program, with a particular focus on the preparation of nurse leaders. CONCLUSION: There is an ongoing need to understand beliefs and values, and styles of interaction and communication, and indeed, ideas about time. With collaboration between Australian academics and Fiji tutors from the Fiji School of Nursing, the program appears to be remarkably successful.  相似文献   
99.
100.
Post-traumatic cerebrospinal fluid (CSF) rhinorrhoea is a well recognized complication of closed head injury. Most cases occur soon after injury and a delay in presentation of more than 1 month is unusual. A case is reported of CSF rhinorrhoea presenting 15 years after initial trauma which was complicated by meningitis after 12 months. The management of this condition is reviewed.  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