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   7052篇
  免费   653篇
  国内免费   24篇
耳鼻咽喉   62篇
儿科学   401篇
妇产科学   112篇
基础医学   1052篇
口腔科学   152篇
临床医学   760篇
内科学   1211篇
皮肤病学   71篇
神经病学   583篇
特种医学   329篇
外科学   1102篇
综合类   133篇
一般理论   4篇
预防医学   741篇
眼科学   96篇
药学   415篇
中国医学   9篇
肿瘤学   496篇
  2021年   99篇
  2020年   61篇
  2019年   117篇
  2018年   117篇
  2017年   106篇
  2016年   84篇
  2015年   117篇
  2014年   150篇
  2013年   237篇
  2012年   296篇
  2011年   323篇
  2010年   186篇
  2009年   164篇
  2008年   272篇
  2007年   262篇
  2006年   284篇
  2005年   262篇
  2004年   299篇
  2003年   259篇
  2002年   264篇
  2001年   212篇
  2000年   224篇
  1999年   198篇
  1998年   102篇
  1997年   101篇
  1996年   82篇
  1995年   100篇
  1994年   87篇
  1993年   94篇
  1992年   170篇
  1991年   162篇
  1990年   134篇
  1989年   142篇
  1988年   169篇
  1987年   144篇
  1986年   157篇
  1985年   134篇
  1984年   75篇
  1983年   96篇
  1982年   68篇
  1981年   58篇
  1980年   65篇
  1979年   71篇
  1978年   69篇
  1977年   56篇
  1976年   61篇
  1974年   59篇
  1973年   67篇
  1972年   62篇
  1971年   60篇
排序方式: 共有7729条查询结果,搜索用时 0 毫秒
31.
32.
33.
Background Cosmetic changes are to be expected after radiotherapy for skin tumours. Objectives This study aimed to answer the questions: How frequent are cosmetic changes after soft X‐ray therapy? Do treatment parameters, tumour thickness, localization and size of the irradiated field have a major influence? Were patients irritated by the visual appearance of the irradiated field? Methods In total, 2474 examinations of 1149 irradiated fields were performed. Results Hypopigmentation was found in 64.7% of examinations more than 90 days after therapy, teleangiectases in 43.1%, erythema in 24.8%, and hyperpigmentation in 16.8%. The frequency of hypopigmentation, teleangiectases and hyperpigmentation increased with time from X‐ray exposure; more than 4 years after therapy hypopigmentation was diagnosed in 91.8% and teleangiectases in 82.2% of examinations. Total dose, the time–dose–fractionation factor (TDF), field size and dose per fraction were significantly related to the frequency of cosmetic changes. Incidence rates of cosmetic changes differed by less than 15% if different treatment conditions were compared: thicker vs. thinner tumours, larger vs. smaller fields, higher vs. lower total doses, doses per fraction, and TDF. Frequencies of hypopigmentation, teleangiectases, erythema and hyperpigmentation differed by more than 15% between some localizations on the head. Women reported irritation by the visual appearance of the irradiated field in 12.6% of 1116 interviews, and men in 4.4% of 1284 interviews. Conclusions Cosmetic changes after soft X‐ray therapy are relatively frequent. Treatment parameters, tumour thickness and field size have only a minor influence. Few patients, but more women than men, were irritated by the visual appearance of the irradiated field.  相似文献   
34.
BACKGROUND: Duplex surveillance of infrainguinal vein grafts may not be efficient. METHODS: Consecutive patients who had received infrainguinal vein grafts were enrolled in a duplex surveillance program. A first scan at 6 weeks after surgery categorized grafts into four groups: (a) low risk grafts, (b) mild flow disturbance, (c) intermediate stenosis and (d) critical stenosis. Disease progression was assessed over time. RESULTS: Of 364 grafts followed-up for a median of 23 months, 236 (65%) had no flow abnormality at 6-weeks, and had a 40-month cumulative patency rate of 82%. The remaining 128 (35%) grafts had a flow disturbance. Of 29 critical stenoses, 15 were repaired, 11 occluded and three did not change. Of 57 intermediate lesions, 32 progressed to critical, nine occluded, two were repaired and 14 did not change or improved. Of 42 mild lesions, 16 progressed to a higher grade, four occluded and 22 did not change or improved. There was no significant difference in graft patency between grafts with repaired stenoses and those without stenoses, but grafts with untreated critical stenoses were associated with lower patency (p<0.001). CONCLUSIONS: A duplex scan 6 weeks after operation can predict those patients who require continuing duplex surveillance.  相似文献   
35.
36.
In July 1984, the first national Australian Nosocomial Prevalence Survey collected data on 12,742 surgical patients from 265 hospitals. This sample represented 59% of public and private hospitals with 50 or more acute-care beds in Australia. The infection control officers at each hospital provided data on patients in a random sample of beds. The over-all surgical wound infection rate was 4.6%. The surgical wound infection rate was twice (5.4%) as high in public than in private (2.8%) hospitals. The infection rates were greater in larger hospitals in both the public and private sector. However, after adjusting for the other predictor factors that are noted below the infection rate did not show any particular pattern for the size of hospital. Clean surgery had a higher (4.8%) infection rate than did clean-contaminated surgery (2.9%). The infection rate for contaminated surgery was 15.0%. Men were found to have nearly twice (6.5%) the infection rate of women (3.4%). Infection rates were lowest in the 15-to-34 years' age-group and highest in those of over 55 years of age. These trends remained even after adjusting for the other risk factors for infection. The cost of surgical wound infections for all hospitals during the year of 1984 was estimated at approximately $60 million. We suggest that a concerted effort should be made to attempt to reduce the infection rate for clean surgery to 1% or less.  相似文献   
37.
We report meningioma of the floor of the anterior cranial fossa with bilateral, symmetrical intraorbital extension, describing the findings on plain films and CT.  相似文献   
38.
39.
Subclavian vein thrombosis: a continuing challenge   总被引:3,自引:0,他引:3  
S L Hill  R E Berry 《Surgery》1990,108(1):1-9
Subclavian vein thrombosis is a relatively uncommon but potentially morbid disease entity. To determine the frequency, cause, and best mode of treatment of this problem, we performed a chart review of all patients with a diagnosis of subclavian vein thrombosis at two major metropolitan hospitals during a 6-year period. A total of 40 patients were identified with subclavian vein thrombosis, which represented 3.5% of all venous thromboses detected during the 6-year period. No side or sex predilection was noted and the majority of patients were outpatients. The cause was fairly evenly divided among intravenous catheters (32%), anatomic abnormalities (45%), and carcinoma with postoperative radiation (22.5%). Despite the increasing use of the subclavian veins for pacemaker leads, hyperalimentation, and permanent intravenous access for chemotherapy, there has not been an increase in diagnosed subclavian vein thrombosis. Anatomic abnormalities with compression of the vein respond well to either heparinization or lytic therapy but require surgery if the venous abnormality persists. Treatment consisted of lytic therapy in 20%, heparinization in 55%, and elevation with removal of the central line in 25% of patients. All patients responded well to treatment, with a decrease in swelling and symptoms; no patient progressed to venous gangrene and only one (2.5%) had a documented pulmonary embolus. Medical treatment provides excellent long-term benefit in most cases unless complicated by an anatomic abnormality.  相似文献   
40.
The purpose of this pilot study was to determine the effects of the addition of coping skills training for obese multiethnic parents whose overweight children were attending a weight management program. At 6 months, parents in the experimental group had significantly lower body mass index (BMI) and body fat percentage (BFP) and higher numbers of pedometer steps compared with those in the control group. Parents in the experimental group also demonstrated significant improvement in interpersonal relationships, behavior control, and stress management compared with those in the control group. Children in the experimental group demonstrated trends toward decreased BMI and BFP and increased pedometer steps.  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