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   6045篇
  免费   329篇
  国内免费   36篇
耳鼻咽喉   36篇
儿科学   210篇
妇产科学   127篇
基础医学   777篇
口腔科学   156篇
临床医学   468篇
内科学   1225篇
皮肤病学   121篇
神经病学   408篇
特种医学   372篇
外科学   708篇
综合类   46篇
预防医学   631篇
眼科学   293篇
药学   411篇
  1篇
中国医学   6篇
肿瘤学   414篇
  2023年   28篇
  2022年   63篇
  2021年   123篇
  2020年   64篇
  2019年   104篇
  2018年   125篇
  2017年   100篇
  2016年   93篇
  2015年   132篇
  2014年   145篇
  2013年   179篇
  2012年   299篇
  2011年   311篇
  2010年   187篇
  2009年   162篇
  2008年   283篇
  2007年   301篇
  2006年   327篇
  2005年   312篇
  2004年   322篇
  2003年   287篇
  2002年   283篇
  2001年   218篇
  2000年   184篇
  1999年   165篇
  1998年   99篇
  1997年   97篇
  1996年   106篇
  1995年   54篇
  1994年   59篇
  1993年   39篇
  1992年   102篇
  1991年   83篇
  1990年   83篇
  1989年   101篇
  1988年   110篇
  1987年   68篇
  1986年   68篇
  1985年   62篇
  1984年   66篇
  1983年   40篇
  1982年   28篇
  1981年   27篇
  1979年   26篇
  1978年   33篇
  1976年   25篇
  1975年   21篇
  1974年   22篇
  1973年   34篇
  1968年   18篇
排序方式: 共有6410条查询结果,搜索用时 15 毫秒
1.
2.
3.
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   
4.
5.
6.
A monoclonal antibody raised by immunization of BALB/c mice with erythrocytic stages of Plasmodium vivax was shown to react with asexual erythrocytic stages of P. chabaudi. The cross-reactivity molecules are antigens of 200 and 148 kDa in P. vivax and of 190 and 70 kDa in P. chabaudi. Immunofluorescence studies of the erythrocytic stages of P. vivax and P. chabaudi indicated that expression of these antigens increased as the parasites' developed from the ring stage to the schizont stage. In the mature trophozoites of P. chabaudi, immunoelectron microscopy revealed clusters of antigen distributed in the cytoplasm of the parasitized erythrocyte. In the schizont, packets of antigen were found associated with the parasitophorous vacuole and the cytoplasm of the infected host cell. Received: 19 March 1996 / Accepted: 28 August 1996  相似文献   
7.
Several articles have been published that bring attention to the destructive potential of tire explosions. Although the severity of tire explosion injuries to the head and neck region is well established, only one previous article has reported injuries to the upper extremity. Fourteen patients with upper extremity tire explosion injuries have been treated by us from 1980 to 1988. Each injury was caused by single-piece wheel assemblies, as opposed to multipiece wheel assemblies, which have traditionally been associated with the injury. Three representative patient reports are discussed. Prevention of this injury can be achieved by increased public awareness, formal industrial safety training, tire servicing with dedicated equipment including restraining devices or barriers, complete evaluation of wheel/tire serviceability before tire mounting, separation of servicing of single and multipiece wheels, and complete tire deflation before servicing.  相似文献   
8.
9.
Over the past decade, the unfortunate reality is that the income gap has widened between Canadian families. Educational outcomes are one of the key areas influenced by family incomes. Children from low-income families often start school already behind their peers who come from more affluent families, as shown in measures of school readiness. The incidence, depth, duration and timing of poverty all influence a child’s educational attainment, along with community characteristics and social networks. However, both Canadian and international interventions have shown that the effects of poverty can be reduced using sustainable interventions. Paediatricians and family doctors have many opportunities to influence readiness for school and educational success in primary care settings.  相似文献   
10.
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