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   1338567篇
  免费   112541篇
  国内免费   6371篇
耳鼻咽喉   16705篇
儿科学   43005篇
妇产科学   36559篇
基础医学   183641篇
口腔科学   36273篇
临床医学   120689篇
内科学   278519篇
皮肤病学   31886篇
神经病学   110519篇
特种医学   55534篇
外国民族医学   274篇
外科学   210372篇
综合类   31529篇
现状与发展   2篇
一般理论   414篇
预防医学   106667篇
眼科学   28086篇
药学   93720篇
  5篇
中国医学   2229篇
肿瘤学   70851篇
  2018年   13378篇
  2017年   10632篇
  2016年   12801篇
  2015年   14300篇
  2014年   19952篇
  2013年   29745篇
  2012年   36246篇
  2011年   38901篇
  2010年   24374篇
  2009年   23910篇
  2008年   36371篇
  2007年   38782篇
  2006年   39914篇
  2005年   38493篇
  2004年   36729篇
  2003年   35823篇
  2002年   33838篇
  2001年   66053篇
  2000年   67923篇
  1999年   56589篇
  1998年   16723篇
  1997年   15018篇
  1996年   16015篇
  1995年   16232篇
  1994年   15099篇
  1993年   14155篇
  1992年   47098篇
  1991年   45748篇
  1990年   43970篇
  1989年   41815篇
  1988年   38758篇
  1987年   38081篇
  1986年   35859篇
  1985年   34635篇
  1984年   26358篇
  1983年   22108篇
  1982年   13847篇
  1981年   12447篇
  1980年   11718篇
  1979年   23544篇
  1978年   17072篇
  1977年   14385篇
  1976年   13182篇
  1975年   13722篇
  1974年   16093篇
  1973年   15396篇
  1972年   14173篇
  1971年   13036篇
  1970年   11880篇
  1969年   11101篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
141.
142.
The urological complications of 320 consecutive renal transplants performed at our institution between October 17, 1985 and November 10, 1989 are reviewed. The Leadbetter-Politano technique of ureteroneocystostomy was used in the first 160 patients (group 1) and an anterior extravesical technique modified from the methods of Witzel, Sampson and Lich was performed in the second 160 patients (group 2). Urological complications occurred in 15 patients (9.4%) in group 1 and 6 (3.7%) in group 2 (p = 0.04). Ureterovesical junction obstruction occurred in 6 patients (3.7%) in group 1 and 1 (0.6%) in group 2 (p = 0.05). Complications of leakage, ureteral necrosis and ureteral stricture were comparable in the 2 groups. Therefore, we advocate the use of the anterior extravesical technique over Leadbetter-Politano ureteral reimplantation based on the lower incidence of urological complications and various technical advantages, including less operative time, avoidance of a separate cystotomy, less hematuria and ability to use short donor ureters.  相似文献   
143.
Preservation of the breast with a good or excellent cosmetic appearance is achievable in most patients. Careful attention to the details of surgical technique allows these procedures to be carried out easily and comfortably for the patient and the surgeon alike.  相似文献   
144.
Thirteen cases of primary appendicular adenocarcinoma are reported. This rare tumour usually presents as acute appendicitis. The correct diagnosis is rarely entertained before or during surgery. The main treatment choice lies between appendicectomy alone and appendicectomy followed by right hemicolectomy. There are anatomical reasons for advising the latter and survival figures from the literature tend to support this preference. The cases reported here indicate that in the period 1972-1984, in the North West Region, there was a slight preference for appendicectomy alone. The additional procedure of right hemicolectomy did not confer any clear-cut survival advantage.  相似文献   
145.
146.
BACKGROUND: The aim was to determine the influence of the socioeconomic status of the family and the hygienic practices in the home on the prevalence of head lice infestation in children. METHODS: The study was carried out by analyzing the answers to a standardized epidemiological questionnaire given to parents of school children aged 4-17 in Bet Shemesh, a medium-sized urban town 25 km from Jerusalem. RESULTS: Of 3,000 questionnaires distributed, 958 (31.9%) were completed and returned. The majority of the children (72.4%) had been previously infested with lice. Half of them had other family members, mainly brothers and sisters, who had been infested in the past with lice. In 97.5% of the families the mother was responsible for examining the children for lice, and for carrying out treatment when infestation was present. An association was found between presence of lice infestation and mother's education, age of child, and frequency of shampooing, combing, and examination for lice. There was no association between infestation rates and mother's country of origin, crowding in the home, and the sharing of combs, brushes, hats, scarves, towels, and clothes. CONCLUSIONS: There is evidence that the incidence of lice infestation depends on the hygienic practices in the home rather than on the socioeconomic status of the family or sharing of personal articles among family members.  相似文献   
147.
148.
The results of a controlled randomized and prospective clinical study including 113 patients from March 1987 until August 1988 showed that prophylactic drainage in elective resection for cancer of the colon was not necessary. 60 patients received a drain, 53 patients were not drained. The drain turned out to be ineffective even concerning its expected function of draining intraabdominal fluid: its diagnostic and therapeutic value failed in clinical practice. The rate of surgical complications--i.e. anastomotic leakage, impaired wound healing and relaparotomy--was significantly higher in the drained group. In elective colon resection the use of a drain as a routine procedure cannot be recommended.  相似文献   
149.
Serum bone-gla protein after fracture   总被引:2,自引:1,他引:1  
Serum bone Gamma-carboxyglutamic acid (bone-gla) protein (BGP), a marker of bone formation, was measured in serial blood samples drawn from 14 patients who had fractured at least one of their tibial or femoral diaphyses and from two other patients who had sustained major trauma without fracture but who had been immobilized. A total of 85 samples were taken and analyzed during the first three months after the fractures occurred. Serum BGP significantly increased and positively correlated with the time that had elapsed after the fracture, with an average twofold increase after two months. The fracture site and the duration of immobilization had no influence on the serum BGP levels. Serum BGP levels from the two non-fractured cases increased in the first two weeks with no subsequent consistent trend. These data suggest that serum BGP increases one to two months after a major fracture, possibly as a manifestation of bone repair. Further studies are required to determine the potential clinical value of serum BGP in the management of such patients.  相似文献   
150.
Study Objective . To characterize cytochrome P450 (CYP) 3A4 activity in premenopausal and postmenopausal women by evaluating the urinary 6-β-hydroxycortisokcortisol ratio. Design . Prospective study. Subjects . Thirteen premenopausal and 13 postmenopausal women who were healthy and not receiving drugs known to affect CYP3A4 activity. Interventions . Beginning on day 2 of menses, premenopausal women collected first morning urine samples every other day for a complete menstrual cycle. Postmenopausal women collected first morning urine every other day for 28 days. Measurements and Main Results . Mean weekly 6-β-hydroxycortisol:cortisol ratios did not differ during the phase (week) of the menstrual cycle. Daily ratios did not differ in postmenopausal women. No difference between premenopausal and postmenopausal women was found on comparing overall median ratios. Conclusion . Cytochrome P450 3A4 activity as measured by 6-β-hydroxy cortisol:cortisol ratio did not differ by week of menstrual cycle, suggesting no menstrual cycle-related changes. Menopause does not appear to be associated with differences in CYP3A4 activity, compared with premenopause.  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