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   2398525篇
  免费   187301篇
  国内免费   9804篇
耳鼻咽喉   30716篇
儿科学   78364篇
妇产科学   65566篇
基础医学   340278篇
口腔科学   66098篇
临床医学   226235篇
内科学   475409篇
皮肤病学   52879篇
神经病学   199106篇
特种医学   92448篇
外国民族医学   625篇
外科学   352954篇
综合类   55415篇
现状与发展   3篇
一般理论   848篇
预防医学   201367篇
眼科学   51909篇
药学   172550篇
  11篇
中国医学   4918篇
肿瘤学   127931篇
  2018年   26525篇
  2017年   20455篇
  2016年   23342篇
  2015年   26443篇
  2014年   36715篇
  2013年   56164篇
  2012年   72520篇
  2011年   77607篇
  2010年   46714篇
  2009年   44458篇
  2008年   71509篇
  2007年   75865篇
  2006年   77145篇
  2005年   74550篇
  2004年   71058篇
  2003年   68405篇
  2002年   65602篇
  2001年   109769篇
  2000年   112838篇
  1999年   94728篇
  1998年   28261篇
  1997年   25403篇
  1996年   25990篇
  1995年   25603篇
  1994年   23979篇
  1993年   22480篇
  1992年   77467篇
  1991年   75627篇
  1990年   72987篇
  1989年   69353篇
  1988年   64451篇
  1987年   63184篇
  1986年   60038篇
  1985年   57701篇
  1984年   43958篇
  1983年   37081篇
  1982年   22962篇
  1981年   20505篇
  1980年   19202篇
  1979年   39782篇
  1978年   28829篇
  1977年   23940篇
  1976年   22784篇
  1975年   23512篇
  1974年   28167篇
  1973年   27222篇
  1972年   25162篇
  1971年   23301篇
  1970年   21427篇
  1969年   19844篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare malignant tumour of the skin, with an estimated incidence of 0.8 to five cases per 1 million people per year. OBJECTIVE: To study epidemiological, immunohistochemical and clinical features, delay in diagnosis, type of treatment and outcome of DFSP from 1982 to 2002. METHODS: Using data from the population-based cancer registry, 66 patients with pathologically proved DFSP were included (fibrosarcomatous DFSP were excluded). Each patient lived in one of the four departments of Franche-Comté (overall population of 1 million people) at the time of diagnosis. The main data sources came from public and private pathology laboratories and medical records. The rules of the International Agency for Research on Cancer were applied. RESULTS: The estimated incidence of DFSP in Franche-Comté was about three new cases per 1 million people per year. Male patients were affected 1.2 times as often as female patients were. The trunk (45%) followed by the proximal extremities (38%) were the most frequent locations. DFSP occurred mainly in young adults between 20 and 39 years of age. Mean age at diagnosis was 43 years, and the mean delay in diagnosis was 10.08 years. Our 66 patients initially underwent a radical local excision. Among them, 27% experienced one or more local recurrences during 9.6 years of follow-up. There was one regional lymph node recurrence without visceral metastases. These recurrences were significantly related to the initial peripheral resection margins. We observed a local recurrence rate of 47% for margins less than 3 cm, vs. only 7% for margins ranging from 3 to 5 cm [P=0.004; OR=0.229 (95%, CI=0.103-0.510)]. The mean time to a first local recurrence was 2.65 years. Nevertheless, there was no death due to the DFSP course at the end of the follow-up, and the final outcome was favourable. CONCLUSION: Our study emphasizes the importance of wide local excision with margins of at least 3 cm in order to prevent local recurrence. However, the recent development of inhibitors of signal transduction by the PDGFB pathway should soon modify the surgical strategy, which is often too mutilating.  相似文献   
62.
Endoscopic clips have been used mainly for control of gastrointestinal (GI) bleeding and occasionally for closure of GI perforations. However, closure of spontaneous esophageal perforation (Boerhaave's syndrome) by clipping has not been reported. We described successful non-surgical closure of spontaneous esophageal perforation by endoscopic clipping in a patient with bilateral pyopneumothorax and septicemia.  相似文献   
63.
64.
65.
66.
Primary chemotherapy administered to breast cancer patientsis the best model to identify baseline features able to predictwhich patients may be most likely to benefit or not from a cytotoxicregimen. In the March issue of Annals of Oncology two papersevaluated the predictive role of immunohistochemical p53 expressionon  相似文献   
67.
68.
69.
70.
PURPOSE: In children with locally advanced or recurrent malignant tumours, prognosis can be improved by regional deep hyperthermia (RHT) in combination with platin-based chemotherapy. However, because of the increasing number of patients that achieve long-time remission with this therapy, it is necessary to evaluate long-term sequelae of thermochemotherapy. During the years 1993-2004 one has observed avascular osteonecrosis (AON) of the femoral head after RHT in seven children with pelvic germ cell tumours or rhabdomyosarcomas. METHODS: Although AON may develop in patients with malignancies treated with chemo- or radiotherapy alone, RHT might nevertheless contribute to the occurrence of AON. In order to determine potential risk factors for AON after RHT, this study analysed the relationship of AON to the patient's age, medical history and treatment parameters such as thermal dose equivalent and power output. RESULTS AND CONCLUSIONS: In the present study AON was associated with young age as well as intensity of hyperthermia indicated by high power levels that exceed 20 W per kg body weight and/or application of eight or more heat sessions as well as additional radiotherapy. Based on this observation, it was assumed that an optimized three dimensional thermal field modelling may be helpful to avoid hazardous temperatures in the femoral heads during RHT treatment and to reduce AON of the femoral heads.  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