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   1314939篇
  免费   97842篇
  国内免费   1820篇
耳鼻咽喉   17064篇
儿科学   42272篇
妇产科学   35766篇
基础医学   195271篇
口腔科学   35845篇
临床医学   123004篇
内科学   258373篇
皮肤病学   28232篇
神经病学   107184篇
特种医学   48353篇
外国民族医学   265篇
外科学   187096篇
综合类   26279篇
现状与发展   3篇
一般理论   636篇
预防医学   108469篇
眼科学   29185篇
药学   95733篇
  10篇
中国医学   2076篇
肿瘤学   73485篇
  2019年   10969篇
  2018年   14712篇
  2017年   11282篇
  2016年   12328篇
  2015年   14187篇
  2014年   19637篇
  2013年   29773篇
  2012年   41125篇
  2011年   43853篇
  2010年   25230篇
  2009年   24275篇
  2008年   41205篇
  2007年   44035篇
  2006年   43492篇
  2005年   42676篇
  2004年   40901篇
  2003年   39161篇
  2002年   37923篇
  2001年   56449篇
  2000年   57418篇
  1999年   48558篇
  1998年   14001篇
  1997年   12730篇
  1996年   13087篇
  1995年   12362篇
  1994年   11481篇
  1993年   10716篇
  1992年   38496篇
  1991年   37895篇
  1990年   36664篇
  1989年   35434篇
  1988年   32914篇
  1987年   32219篇
  1986年   30724篇
  1985年   28989篇
  1984年   22152篇
  1983年   19403篇
  1982年   11662篇
  1979年   21056篇
  1978年   15526篇
  1977年   12908篇
  1976年   11914篇
  1975年   12865篇
  1974年   15645篇
  1973年   15429篇
  1972年   14538篇
  1971年   13571篇
  1970年   12800篇
  1969年   12085篇
  1968年   11235篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
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   
53.
In rare cases the usage of the internal thoracic vessels as recipient vessels in reconstructive surgery of the head and neck region with free tissue transfer is a challenging but valid alternative if local recipient vessels are unusable.  相似文献   
54.
55.
56.
Cutaneous plasmacytosis is a rare disorder characterized by a benign proliferation of mature plasma cells that appears as multiple dark-brown to purplish skin lesions, often associated with polyclonal hypergammaglobulinaemia. We present the case of a 55-year-old Caucasian man who suffered from a cutaneous plasmacytosis associated with two different carcinomas. Cutaneous plasmacytosis seems to be a reactive process because most cases reported are not associated with any apparent underlying disease. Nevertheless, because few reported cases were associated with malignancies, screening of additional neoplasms would be justified.  相似文献   
57.
Cell physiology and molecular biology typically follow a reductionistic approach in science. In the last decade, molecular principles and pathogenetic factors involved in the development of many diseases have been successfully discovered. Therefore, early biological concepts based on systemic and cybernetic thoughts have been largely overshadowed by these more recent molecular and pathogenetic factors. This review highlights discoveries on bone development and hypothalamic controlled feeding and eating behavior with a cybernetic and systemic perspective. Interestingly, ancient ideas on bone development and hypothalamic function are still reasonable considerations to embed new molecular discoveries into a systemic concept of principles organizing nature.  相似文献   
58.
59.
60.
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