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   1181489篇
  免费   80738篇
  国内免费   1735篇
耳鼻咽喉   16688篇
儿科学   33414篇
妇产科学   32151篇
基础医学   170605篇
口腔科学   34734篇
临床医学   101127篇
内科学   229316篇
皮肤病学   24665篇
神经病学   89906篇
特种医学   46522篇
外国民族医学   120篇
外科学   190676篇
综合类   24619篇
现状与发展   2篇
一般理论   380篇
预防医学   79204篇
眼科学   27440篇
药学   90227篇
  3篇
中国医学   2835篇
肿瘤学   69328篇
  2018年   11968篇
  2017年   9230篇
  2016年   10341篇
  2015年   11763篇
  2014年   15894篇
  2013年   23602篇
  2012年   31660篇
  2011年   32978篇
  2010年   20075篇
  2009年   19000篇
  2008年   31892篇
  2007年   33731篇
  2006年   34319篇
  2005年   33001篇
  2004年   31917篇
  2003年   30549篇
  2002年   29719篇
  2001年   65100篇
  2000年   67220篇
  1999年   55867篇
  1998年   13213篇
  1997年   11782篇
  1996年   11743篇
  1995年   11056篇
  1994年   10198篇
  1993年   9431篇
  1992年   42123篇
  1991年   40720篇
  1990年   39514篇
  1989年   38356篇
  1988年   34990篇
  1987年   34057篇
  1986年   31879篇
  1985年   30511篇
  1984年   21804篇
  1983年   18610篇
  1982年   9896篇
  1979年   19613篇
  1978年   13418篇
  1977年   11488篇
  1976年   10083篇
  1975年   11159篇
  1974年   13455篇
  1973年   12876篇
  1972年   12159篇
  1971年   11493篇
  1970年   10970篇
  1969年   10261篇
  1968年   9496篇
  1967年   8678篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Of 431 patients with gastric cancer observed in our institution, 23 (5.3%) had early gastric cancer (EGC). Macroscopic presentation, histology, depth of invasion, and lymph node involvement were evaluated in all the cases. All patients underwent surgery and an intensive follow-up was performed. Five of the 23 patients progressed, and the risk factors were examined. Histology seemed to be the main prognostic factor in our study, since intestinal type of EGC was associated to a significantly better prognosis. Total gastrectomy is indicated in the proximal localization of EGC, and should perhaps be performed also in cases presenting undifferentiated histology.  相似文献   
82.
An increase in the number of cases of tuberculosis, especially in children, has been observed recently. Post-vaccination conversion rate in babies immunised with BCG was assessed. Sensitization was detected as early as 4 weeks after BCG inoculation. Although 84.2% had physical evidence of BCG inoculation only 69.8% had developed detectable sensitization to the tubercle bacilli as shown by the Mantoux test.  相似文献   
83.
In 1985 an outbreak of ornithosis affected 13 of 80 (16%) workers in a duck-processing plant. New employees were three times more likely to become cases than established employees. The highest attack rate was in those on the production line. Following the outbreak, an occupational health scheme was set up to monitor the health of new recruits to the company. Serological evidence of recent infection was demonstrated in 18 of 37 (49%) new employees tested in the first 3 months of employment. Five (14%) also had clinical evidence of ornithosis. Veterinary investigation of the ducks demonstrated a high proportion with asymptomatic chlamydial infection. It is suggested that ornithosis may be more common in duck processors than is currently supposed. Strategies to reduce occupational risks are discussed.  相似文献   
84.
85.
Two-color flow cytometry was carried out to determine the correlation between cell-mediated immunity and the levels of proteinuria in 30 patients with membranous nephropathy. Lymphocyte subpopulations were measured by two-color flow cytometry using various monoclonal antibodies of the Leu series. Clinically, the patients were divided into four stages as follows: 1. untreated nephrotic stage, 2. prednisolone (PSL) treated nephrotic stage, 3. persistent proteinuric stage (incomplete remission, ICR) and 4. complete remission (CR). Two-color flow cytometry showed a significant decrease in Leu 2a+15+ (suppressor T) cells and relative increase in Leu 3a+8+ (suppressor inducer T) cells in the untreated nephrotic stage. The mean Leu 3a+8-/Leu 2a+15+ (helper/suppressor) cell ratio was normalized in the persistent proteinuric stage or complete remission after treatment with PSL. Patients with membranous nephropathy showed a significant elevation of Leu 2a+DR+ cells after treatment with PSL. The abnormalities of suppressor T cells and suppressor inducer T cells in the peripheral blood appear to reflect the levels of proteinuria in patients with membranous nephropathy. It was concluded that PSL might stimulate Leu 2a positive cells and then increase the number of Leu 2a+15+ cells in the peripheral blood of patients with membranous nephropathy.  相似文献   
86.
Premalignant lesions of the penis include cutaneous horn, balanitis xerotica obliterans, and leukoplakia. The true incidence of progression of each of these to squamous-cell carcinoma is unknown. Bowenoid papulosis, erythroplasia of Queyrat, and Bowen's disease are histologically identical to in situ carcinoma. Although the first is consistently benign, the latter two regularly evolve into invasive cancer. Malignant scrotal lesions include squamous-cell carcinoma, liposarcoma, leiomyosarcoma, basal-cell carcinoma, extramammary Paget's disease, erythroplasia of Queyrat, malignant melanoma, and metastases. Hemangioma can be confused with carcinoma.  相似文献   
87.
88.
89.
Cerebral function in normoxia and its reactions to standard periods of hypoxia of increasing severity were studied in 30 newborn guinea pigs less than 3 days old. Intrauterine growth retardation was induced either by uterine artery ligation at midgestation or by feeding the female in late gestation with khat leaves, an amphetamine-like stimulant chewed by men and women in several countries in eastern Africa and Arabia. After spontaneous delivery, the neonates were anesthetized and ventilated. Cardiovascular, metabolic, and neurophysiologic (somatosensory evoked potentials) parameters were monitored. Under normoxia, the khat-exposed group showed prolonged latency of the primary response of the somatosensory evoked potentials and a reduced amount of secondary components. Under hypoxia, this group also has a greater reduction of amplitude of the somatosensory evoked potentials. It is concluded that khat exposure during fetal life has an impact on the cerebral function during the neonatal period (at least up to 3 days of age) which is not solely explained by the concomitantly produced growth retardation.  相似文献   
90.
This study examined electromyogram (EMG) and skin conductance level (SCL) as mediators of neuropsychological test performance of alcoholics. Alcoholics and controls with high EMG performed less well than low EMG subjects on 12 measures of neuropsychological performance. For SCL, the alcoholics and controls in the Low Group did not differ from those in the High Group on any measure. Analyses that used information intake (Low EMG and High SCL) and rejection (High EMG and Low SCL) information postures (IPs) demonstrated that the intake group outperformed the rejection group on 10 neuropsychological measures. Subjects with intake IPs reported more stimulation, concentration, and interest during the tasks than did subjects with rejection IPs. Results suggest that IPs can be used to identify alcoholics with neuropsychological deficits.  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