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   1457604篇
  免费   105604篇
  国内免费   4651篇
耳鼻咽喉   18513篇
儿科学   47295篇
妇产科学   40067篇
基础医学   214800篇
口腔科学   39469篇
临床医学   138029篇
内科学   285518篇
皮肤病学   30565篇
神经病学   122263篇
特种医学   51075篇
外国民族医学   394篇
外科学   198949篇
综合类   29419篇
现状与发展   1篇
一般理论   492篇
预防医学   126670篇
眼科学   31520篇
药学   107811篇
  6篇
中国医学   3535篇
肿瘤学   81468篇
  2021年   13828篇
  2019年   14429篇
  2018年   19952篇
  2017年   14613篇
  2016年   15632篇
  2015年   17806篇
  2014年   24346篇
  2013年   37199篇
  2012年   51884篇
  2011年   54632篇
  2010年   31474篇
  2009年   28754篇
  2008年   48970篇
  2007年   51600篇
  2006年   51573篇
  2005年   49949篇
  2004年   47492篇
  2003年   44964篇
  2002年   43571篇
  2001年   64109篇
  2000年   65667篇
  1999年   55066篇
  1998年   15564篇
  1997年   13947篇
  1996年   13735篇
  1995年   12990篇
  1994年   12096篇
  1993年   11354篇
  1992年   43009篇
  1991年   42176篇
  1990年   40710篇
  1989年   38527篇
  1988年   35637篇
  1987年   34764篇
  1986年   33132篇
  1985年   31578篇
  1984年   23749篇
  1983年   20218篇
  1982年   12133篇
  1979年   21513篇
  1978年   15295篇
  1977年   12454篇
  1976年   12274篇
  1975年   12613篇
  1974年   15456篇
  1973年   15110篇
  1972年   13907篇
  1971年   12932篇
  1970年   12024篇
  1969年   10931篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
The increased number of lymphocytes in airways during an asthmatic response is believed to be the result of increased recruitment of these cells. However, it is possible that a decreased apoptotic rate could also contribute to the increased number. The aim of the present study was to investigate whether allergen airway provocation influences the apoptotic phenotype of lung and peripheral blood lymphocytes (PBL) in subjects with atopic asthma. Bronchoalveolar lavage (BAL) lymphocytes and PBL from 12 asthmatic subjects previously challenged with allergen (n = 7) or saline (n = 5) were exposed to the apoptotic stimulus tributyltin (TBT) in vitro and assayed for apoptosis. Airway allergen provocation resulted in decreased sensitivity of BAL lymphocytes to TBT-induced apoptosis, with 42.2% (range 33.9-62.5%) apoptotic cells before challenge versus 23.5% (range 15.3-42.4%) after challenge, while PBL were unaffected. The increased apoptosis resistance correlated with higher numbers of Bcl-2-expressing lymphocytes. Interestingly, baseline caspase-3-like activity was significantly elevated in viable BAL lymphocytes compared with viable PBL, and was unaltered by allergen exposure. In conclusion, allergen inhalation renders bronchoalveolar lavage lymphocytes more resistant to apoptosis while peripheral blood lymphocytes were not influenced at all, indicating that the apoptotic phenotype of airway lymphocytes may play a role in asthmatic inflammation.  相似文献   
73.
Pancreatic panniculitis is an uncommon condition that can occur in association with pancreatic disease. We present a case of pancreatic panniculitis in a female pancreas-kidney transplant recipient 5 months post-transplant. The patient was on standard immunosuppressive medications and had acute rejection of her renal allograft. The diagnosis of allograft pancreatitis and rejection presenting with pancreatic panniculitis was supported clinically, histopathologically and by laboratory and imaging data. This is the fourth case of pancreatic panniculitis occurring in a transplant recipient and the first in a simultaneous pancreas-kidney transplant recipient. It is also the first case associated with allograft rejection. Clinicians should be aware that pancreatic panniculitis may be a manifestation of underlying allograft pancreatic disease.  相似文献   
74.
The purpose of this study is to determine the role of liver biopsy and outcome of patients undergoing donor evaluation for adult-to-adult right hepatic lobe living donor liver transplantation (LDLT). Records of patients presenting for a comprehensive donor evaluation between 1997 and February 2005 were reviewed. Liver biopsy was performed only in patients with risk factors for abnormal histology. Two hundred and sixty patients underwent a comprehensive donor evaluation and 116 of 260 (45%) were suitable for donation, 14 of 260 (5.4%) did not complete evaluation and 130 of 260 (50%) were rejected. Four patients underwent unsuccessful hepatectomy surgery due to discovery of intraoperative abnormalities. Between 1997 and 2001, the acceptance rate of donor candidates (63%) was higher than 2002-2005 (36%), p < 0.0001. Sixty-six of the 150 eligible patients (44%) fulfilled criteria for liver biopsy and 28 of 66 (42%) had an abnormal finding. Less than half of the patients undergoing donor evaluation were suitable donors and the donor acceptance rate has declined over time. A large proportion of the patients undergoing liver biopsy have abnormal findings. Our evaluation process failed to identify 4 of 103 who had aborted donor surgeries.  相似文献   
75.
Leocani  L.  Comi  G. 《Neurological sciences》2006,27(1):s27-s29
Neurological Sciences - Brain plasticity, intended as the pattern of functional and structural changes in responses to environmental physiological or pathological events, is underlined by several...  相似文献   
76.
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   
77.
78.
79.
80.
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