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   4896篇
  免费   213篇
  国内免费   67篇
耳鼻咽喉   153篇
儿科学   166篇
妇产科学   157篇
基础医学   521篇
口腔科学   182篇
临床医学   427篇
内科学   954篇
皮肤病学   118篇
神经病学   262篇
特种医学   203篇
外国民族医学   1篇
外科学   831篇
综合类   171篇
现状与发展   1篇
一般理论   1篇
预防医学   349篇
眼科学   96篇
药学   291篇
中国医学   62篇
肿瘤学   230篇
  2023年   33篇
  2022年   67篇
  2021年   113篇
  2020年   59篇
  2019年   86篇
  2018年   125篇
  2017年   99篇
  2016年   108篇
  2015年   127篇
  2014年   169篇
  2013年   186篇
  2012年   310篇
  2011年   319篇
  2010年   189篇
  2009年   112篇
  2008年   213篇
  2007年   278篇
  2006年   251篇
  2005年   287篇
  2004年   202篇
  2003年   201篇
  2002年   223篇
  2001年   152篇
  2000年   172篇
  1999年   162篇
  1998年   42篇
  1997年   32篇
  1996年   27篇
  1995年   34篇
  1994年   20篇
  1993年   14篇
  1992年   80篇
  1991年   69篇
  1990年   62篇
  1989年   51篇
  1988年   41篇
  1987年   47篇
  1986年   53篇
  1985年   43篇
  1984年   30篇
  1983年   21篇
  1979年   20篇
  1975年   14篇
  1974年   27篇
  1973年   18篇
  1971年   21篇
  1970年   25篇
  1969年   16篇
  1968年   13篇
  1967年   13篇
排序方式: 共有5176条查询结果,搜索用时 15 毫秒
11.
Using traditional anatomical and histological methods, the muscle envelope of the pharynx-esophagus junction was investigated in humans and dogs. In the upper (cranial) portion of the esophagus of man and dogs, an inferior anatomical sphincter was detected which histologically can be referred to the group of rhabdo-sphincters. The upper esophageal sphincter is a purely esophageal structure which in man is located at a distance of 25-30 cm from the maxillary incisors. In adult humans, it is 25-30 mm long and is situated obliquely to the long esophageal axis. The posterior semicircle of the sphincter is located higher than the anterior one. In the area of the upper esophageal sphincter the esophageal wall is of different thickness. Due to the muscle envelope and submucous membrane of the base, the right wall is 1.7-2.0 times thicker than the left, anterior or posterior wall. The data obtained from fiber esophagoscopy of patients and electromyography of the pharynx-esophagus junction of dogs have shown that the upper (cranial) esophageal sphincter control food passage from the pharynx to the esophagus and prevents food reflux to the laryngopharynx, protecting airways from aspiration.  相似文献   
12.
The results of percutaneous radiofrequency rhizotomy of lumbar spinal facets in 46 patients followed at least three months (mean 15 months) are reported and compared with those reported previously. Satisfactory pain relief three months after the procedure was achieved in 36.4 percent of patients without operations and in 41.7 percent of patients with operations other than fusion.No patient had previously undergone fusion.Treatment of low-back pain by using radio-frequency thermocoagulation of spinal facets is a simple, safe, and well-tolerated procedure. It can be used to relief of pain in spite of decreasing rates of success within the follow-up period.  相似文献   
13.
Increased fibrinolytic activity is a well recognized constant finding observed during cardiopulmonary bypass (CPB). The purpose of the present work was to study and estimate the factors involved in the plasminogen activation and prekallikrein-kallikrein systems in a population of adult patients undergoing open heart surgery with CPB. Plasminogen activator activity determinations with a fibrinolytic method as well as plasminogen activation and prekallikrein-kallikrein determinations with synthetic substrates were carried out. Our results indicate that no active fibrinolysis but a fibrinolytic potential, similar to that observed in blood obtained after venous occlusion, can be demonstrated in circulating plasma during CPB. This fibrinolytic potential is related to the presence of vascular plasminogen activator released from endothelial cells by the CPB stimulus.  相似文献   
14.
Data are presented on hospital stay for the population 65 years-old and over, measured in percentage over the total for Spain, for the 1978 to 1988 period, by gender, for each province and autonomous region (Comunidad Autónoma). The country's total for the last available year was 35%. Except in Baleares and Murcia, the proportion of hospital stays increased in all Regions, especially in Navarra, where it increased from 23% to 51%. After adjusting for age, the increase in the proportion of hospital stays in the study population was due to an increase in utilization per person. The proportion, which was 13.3% in 1978, raised to 23.8% in 1988, with an adjusted value of 21.3%.  相似文献   
15.
玉溪市农村室内鼠类及其体外寄生蚤类调查   总被引:1,自引:0,他引:1  
笔者于1992年2月至1993年1月,在玉溪市两个自然村室内进行了鼠类及体外寄生蚤类调查研究。鼠类年均捕获率7.25%;褐家鼠为优势种,占73.49%,捕获率高峰期在9月;黄胸鼠和小家鼠为常见种,捕获率高峰期分别在3和4月。3种家鼠年龄孕鼠率为14.57%,平均胎仔数为7.3只,10月为全年生殖高峰。  相似文献   
16.
17.
OBJECTIVE: The purpose of this study was to investigate whether Dizziness Handicap Inventory (DHI) score is related to postural performance as assessed by dynamic posturography. STUDY DESIGN: Retrospective study. SETTING: Outpatient in a tertiary referral center. PATIENTS: Ninety-two complete unilateral vestibular loss patients, categorized into 3 groups according to the postlesion stage: 1 to 2 months (n = 32; age, 47.6 +/- 10.7 yr), 4 to 7 months (n= 23; 47.1 +/- 8.37 yr), and 1 year and older (n = 37; 49.2 +/- 9.5 yr). MAIN OUTCOME MEASURES: Dizziness Handicap Inventory and dynamic balance measured with a seesaw platform moving either in the anterior-posterior or in the mediolateral direction. RESULTS: The mean DHI score was 25.8 +/- 18.7 and the range was 0 to 68. Dizziness Handicap Inventory scores did not differ significantly between the different unilateral vestibular loss groups studied. No difference was detected between the groups for the 3 subscores (emotional, functional, and physical), except that the older-than-1-year group had a significantly higher physical score than the 2 others. No correlation was found between DHI scores and postural indicators for either direction of the platform. However, patients unable to maintain balance when the seesaw platform moved in the mediolateral direction had significantly higher DHI scores than those who did not fall. CONCLUSION: Even if they are not directly related, we suggest that DHI and dynamic posturography are complementary approaches for appreciating the vestibular compensation process and are thus useful for postoperative counseling for vestibular loss patients.  相似文献   
18.
19.
OBJECTIVE: The aim of this study is to investigate dose-dependent effect of the topical application of methotrexate (MTX) in rats on the normal nasal mucosa, liver tissue, liver enzymes, and hemoglobin levels. STUDY DESIGN: Preclinical animal study. SETTING: Twenty male adult wistar albino rats were randomly divided into 4 groups (n=5). A single puff of MTX (2.5 microg) was applied to both nasal cavities 2 times a day. The animals were given MTX 1 day a week in group 1, 3 days a week in group 2, and 5 days a week in group 3. Control group animals were given 1 puff of physiologic saline to both nasal cavities 5 days a week and 2 times a day. After 28 days, liver biopsies, blood samples, and 5 nasal mucosal biopsies were taken. Histological examination was made with respect to certain parameters semiquantitatively (grade 0-3). The aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and hemoglobin counts were studied from blood samples. RESULTS: There are no statistically significant differences with respect to histopathological parameters between the control group and the groups 1-3 (P>0.05). Histopathological examination of liver tissue did not reveal any evident difference between the control and study groups. Mean AST and ALT as liver function tests and hemoglobin counts were within normal limits. Topical application of MTX at these doses has no toxic effect on the nasal mucosa, the liver tissue, AST and ALT levels, and hemoglobin level. CONCLUSIONS: These results have been encouraging to investigate use of the topical application of MTX in nasal manifestation of autoimmune disease or addition of the topical application of MTX to the steroid treatment in cases with massive nasal polyposis resistant to steroids and prone to recurrence.  相似文献   
20.
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