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   1367846篇
  免费   98279篇
  国内免费   3034篇
耳鼻咽喉   20091篇
儿科学   40980篇
妇产科学   39345篇
基础医学   191385篇
口腔科学   40710篇
临床医学   116219篇
内科学   269392篇
皮肤病学   30583篇
神经病学   109160篇
特种医学   54792篇
外国民族医学   436篇
外科学   213856篇
综合类   31496篇
现状与发展   6篇
一般理论   460篇
预防医学   94767篇
眼科学   32387篇
药学   102198篇
  3篇
中国医学   3024篇
肿瘤学   77869篇
  2018年   12446篇
  2016年   11144篇
  2015年   12559篇
  2014年   17677篇
  2013年   26752篇
  2012年   35145篇
  2011年   37090篇
  2010年   21999篇
  2009年   21431篇
  2008年   35575篇
  2007年   38746篇
  2006年   39332篇
  2005年   38234篇
  2004年   37248篇
  2003年   36067篇
  2002年   35475篇
  2001年   63883篇
  2000年   65557篇
  1999年   55729篇
  1998年   15114篇
  1997年   13837篇
  1996年   13252篇
  1995年   12520篇
  1994年   11717篇
  1992年   42975篇
  1991年   41477篇
  1990年   40709篇
  1989年   39699篇
  1988年   37120篇
  1987年   36560篇
  1986年   35051篇
  1985年   33272篇
  1984年   25072篇
  1983年   21290篇
  1982年   12985篇
  1981年   11859篇
  1979年   24071篇
  1978年   17241篇
  1977年   15011篇
  1976年   13558篇
  1975年   15401篇
  1974年   18195篇
  1973年   17697篇
  1972年   16916篇
  1971年   15781篇
  1970年   14987篇
  1969年   14400篇
  1968年   13507篇
  1967年   12045篇
  1966年   11295篇
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
891.
892.
893.
Forty-six (85%) basal cell and eight (15%) squamous cell carcinomas of the eyelids were treated with electron beams between 1963 and 1983. Lesion sizes ranged from microscopic to 4 cm, with 28 lesions larger than 1 cm. Thirty-eight lesions were treated with radiotherapy after incisional biopsy, and 16 were treated after excisional biopsy (specimens showed positive margins). Doses varied from 45 to 72 Gy, with daily fractions ranging from 2.12 to 4.0 Gy. There were six disease recurrences (10.9%): three in the treatment field and three at the treatment margin. Four of six recurrences were subsequently controlled by limited surgical excision and repair with preservation of the eye, whereas the other two required enucleation. Treatment sequelae such as skin atrophy, telangiectasis, and cosmetic results were evaluated in terms of radiotherapy parameters, pretreatment surgery, and size of the lesion. In 44 patients, the overall cosmetic result was judged as good to excellent, five patients had a mild to modest degree of deformity, and five had significant deformity. Such deformity was usually associated with tumor destruction or previous surgery. No major complications were noted.  相似文献   
894.
895.
Serum protein electrophoresis (SPEP) data obtained at diagnosis were available for 98 of 342 patients with chronic lymphocytic leukemia (CLL) identified in a population-based case-control epidemiologic study. Patients tested with SPEP at diagnosis were significantly younger, more likely to have lymphadenopathy, and more likely to have had their conditions diagnosed at a university hospital than those not tested. Four categories of electrophoretic patterns were identified: normal (N = 56), hypogammaglobulinemia (N = 28), hypergammaglobulinemia (N = 11), and monoclonal gammopathy (N = 3). A higher proportion of those with hypergammaglobulinemia were black, and patients with hypergammaglobulinemia and monoclonal gammopathy were more likely to die within the first year following diagnosis than patients in the other SPEP groups. No association was found, however, between SPEP pattern and a clinical staging classification for CLL. These findings suggest that SPEP may be a useful adjunct in categorizing possible subtypes of CLL and developing future clinical staging classifications.  相似文献   
896.
Mentally retarded adolescents and MA-matched nonretarded children participated in three experiments designed to examine differences in language-processing efficiency. A compressed speech technique was used in Experiments 1 and 2. Experiment 3 relied on a sentence-picture verification procedure. Our results suggest that retarded and nonretarded individuals differ in the speed with which they are able to execute the semantic-analytic processes but not necessarily the phonological encoding processes that are involved in auditory language comprehension. In addition, the data suggest a possible group difference in the quality of the semantic representation encoded during sentence processing.  相似文献   
897.
898.
Personal characteristics of healthy term pregnant women who chose elective induction or spontaneous onset of labour and the motives for their choice were assessed. Almost 50% of 237 women with uncomplicated pregnancies opted for elective induction when offered the opportunity. These women appeared to have had more complaints during their pregnancy and menstrual periods, more complications in their obstetrical history and to be more anxious about their labour than women who chose a spontaneous onset of labour. Predominant motives were a feeling of safety and the desire to shorten the duration of pregnancy. These characteristics and motives seem to reflect a lack of trust in physical reproductive functions. It is concluded that in evaluating effects of elective induction of labour, pre-existing differences between women who choose elective induction and women who opt for a spontaneous onset must be taken into account.  相似文献   
899.
In this study the utility of operative ultrasound in the surgical management of 98 consecutive patients with liver and gastrointestinal tumors was assessed. All patients had preoperative work-up including ultrasound study of the liver as well as selective hepatic arteriography (50 patients) and computerized tomography of the liver (45 patients). At surgery, inspection and palpation of the liver as well as operative ultrasound examination were performed in all cases. Fifty-six patients were known to have liver tumors before operation, while 42 patients had their liver examined as part of the treatment of a primary gastrointestinal malignancy. A total of 126 liver tumors were found in 58 patients, all of whom were confirmed histologically. Eighteen nodules unsuspected before operation were found at surgery--nine by inspection and palpation of the liver, and nine others that were nonpalpable were found by operative ultrasound only. Eighteen lesions that were missed by all diagnostic modalities were found as secondary lesions on pathologic examination of the resected specimens. In addition to diagnostic applications, operative ultrasound was useful in localizing nodules and permitting guided biopsies deep in the hepatic parenchyma. In eight cases, segmental resections were performed with operative ultrasound to localize the plane of section and to catheterize the intrahepatic portal vein branch afferent to the tumor in order to perform balloon catheter occlusion of the vessel for control of bleeding. Operative ultrasound was found to be important in the surgical management of 19 of 98 patients (19%).  相似文献   
900.
Smoking behavior among participants in the nurses' health study.   总被引:2,自引:1,他引:1       下载免费PDF全文
We analyzed smoking behavior of 91,651 married female nurses, aged 30-55 years in 1976. The prevalence of smoking was similar among all birth cohorts. The largest percentage increase in starting to smoke occurred between ages 15 and 25 years; by age 25, 50 per cent had started smoking. The cessation rate was lowest in earlier birth cohorts and among nurses starting to smoke at earlier ages. The cessation rate increased substantially between 1963-73 compared with the period 1948-58.  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