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   1341385篇
  免费   112733篇
  国内免费   6383篇
耳鼻咽喉   16728篇
儿科学   43102篇
妇产科学   36608篇
基础医学   183994篇
口腔科学   36364篇
临床医学   120923篇
内科学   279147篇
皮肤病学   31903篇
神经病学   110657篇
特种医学   55583篇
外国民族医学   274篇
外科学   210594篇
综合类   31730篇
现状与发展   2篇
一般理论   415篇
预防医学   107052篇
眼科学   28184篇
药学   93986篇
  5篇
中国医学   2278篇
肿瘤学   70972篇
  2018年   13506篇
  2017年   10730篇
  2016年   12878篇
  2015年   14394篇
  2014年   20061篇
  2013年   29873篇
  2012年   36472篇
  2011年   39105篇
  2010年   24470篇
  2009年   23966篇
  2008年   36519篇
  2007年   38918篇
  2006年   40034篇
  2005年   38603篇
  2004年   36820篇
  2003年   35904篇
  2002年   33910篇
  2001年   66110篇
  2000年   67963篇
  1999年   56633篇
  1998年   16743篇
  1997年   15031篇
  1996年   16025篇
  1995年   16246篇
  1994年   15108篇
  1993年   14160篇
  1992年   47120篇
  1991年   45769篇
  1990年   43992篇
  1989年   41832篇
  1988年   38775篇
  1987年   38097篇
  1986年   35870篇
  1985年   34650篇
  1984年   26367篇
  1983年   22120篇
  1982年   13850篇
  1981年   12450篇
  1980年   11728篇
  1979年   23548篇
  1978年   17079篇
  1977年   14389篇
  1976年   13189篇
  1975年   13732篇
  1974年   16100篇
  1973年   15402篇
  1972年   14180篇
  1971年   13043篇
  1970年   11887篇
  1969年   11104篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
We previously reported poorer survival among non-Hispanic blacks and Hispanics with idiopathic pulmonary fibrosis (IPF) compared to non-Hispanic whites at our center. In the current study, we hypothesized that these disparities would exist in a nationwide cohort of wait-listed patients with IPF. We performed a retrospective cohort study of 2635 patients with IPF listed for lung transplantation between 1995 and 2003 at 94 transplant centers in the United States. The age-adjusted mortality rate was higher among non-Hispanic blacks [hazard ratio (HR) = 1.24, 95% confidence interval (CI) 1.06-1.45, p = 0.009] and Hispanics (HR = 1.29, 95% CI 1.06-1.56, p = 0.01) compared to non-Hispanic whites. These findings persisted after adjustment for transplantation, medical comorbidities and socioeconomic status. Worse lung function at the time of listing appeared to explain some of these differences (HR for non-Hispanic blacks after adjustment for forced vital capacity percent predicted = 1.16, 95% CI 0.98-1.36, p = 0.09; HR for Hispanics = 1.21, 95% CI 0.99-1.48, p = 0.056). In summary, black and Hispanic patients with IPF have worse survival than whites after listing for lung transplant.  相似文献   
62.
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   
63.
A 65-year-old man developed acute limb ischemia, severe abdominal wall and lower limb livedo reticularis following a coronary angiogram. The differential diagnoses of acute limb ischemia and multiple cholesterol emboli syndrome (MCES) are discussed. This work was performed at Long Island Jewish Medical Center, 270-05, 76th Avenue, New Hyde Park, NY 11040.  相似文献   
64.
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   
65.
66.
67.
68.
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   
69.
70.
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   
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