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   2779588篇
  免费   193830篇
  国内免费   8025篇
耳鼻咽喉   36698篇
儿科学   90539篇
妇产科学   76041篇
基础医学   390515篇
口腔科学   74610篇
临床医学   250740篇
内科学   556662篇
皮肤病学   67349篇
神经病学   231175篇
特种医学   105573篇
外国民族医学   815篇
外科学   410420篇
综合类   51334篇
现状与发展   5篇
一般理论   1021篇
预防医学   214410篇
眼科学   60325篇
药学   201377篇
  8篇
中国医学   5913篇
肿瘤学   155913篇
  2021年   23691篇
  2019年   24358篇
  2018年   36704篇
  2017年   27363篇
  2016年   30479篇
  2015年   34096篇
  2014年   45733篇
  2013年   68444篇
  2012年   93943篇
  2011年   98389篇
  2010年   58055篇
  2009年   54658篇
  2008年   90725篇
  2007年   96363篇
  2006年   96991篇
  2005年   93088篇
  2004年   89283篇
  2003年   85811篇
  2002年   82506篇
  2001年   131471篇
  2000年   134441篇
  1999年   113329篇
  1998年   32056篇
  1997年   28581篇
  1996年   28803篇
  1995年   27924篇
  1994年   25541篇
  1993年   23863篇
  1992年   86987篇
  1991年   83212篇
  1990年   80371篇
  1989年   77528篇
  1988年   70890篇
  1987年   69316篇
  1986年   64744篇
  1985年   61682篇
  1984年   45874篇
  1983年   38737篇
  1982年   22965篇
  1981年   20371篇
  1979年   39809篇
  1978年   28058篇
  1977年   23845篇
  1976年   21982篇
  1975年   23409篇
  1974年   27518篇
  1973年   26127篇
  1972年   24454篇
  1971年   22617篇
  1970年   20846篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
The new treatment strategy for Peritoneal Surface Malignancy combines a cytoreductive surgery and perioperative intraperitoneal chemotherapy. Cytoreduction removes all macroscopic tumor. Intraperitoneal chemotherapy avoids implantation of microscopic residual tumor cells on intra-abdominal surfaces when it is administered intraoperatively and/or early in the postoperative period. Delivering cytotoxic drugs directly into the peritoneal cavity maximizes dose intensity and minimizes systemic toxicity. Hyperthermia is selectively cytotoxic for malignant cells and potentiates the effect of chemotherapy. Implementation of this procedure makes the perioperative personnel to face a risk of exposure to cytotoxic agents. Furthermore, peritonectomies and electro-evaporation of tumor nodules are performed with high voltage electrocautery, generating a large amount of surgical smoke during several hours. Inhalation of these fumes may be also a risk for healthcare workers. In this article, we analyse in depth these new risks of the operating room personnel, we review the literature, and we give guidelines for secure performance of cytoreductive surgery and hyperthermic intraoperative intraperitoneal chemotherapy, as well as for early postoperative intraperitoneal chemotherapy administration. These new procedures are safe techniques for patients and healthcare workers provided adequate policies are adopted to avoid occupational exposure.  相似文献   
102.
103.
104.
There are no data available combining transbronchial needle aspiration (TBNA) of mediastinal lymph nodes and positron emission tomography (PET) in the staging of nonsmall cell lung cancer (NSCLC). The aim of the current study was to determine if these two methods can enhance the negative predictive value of the individual modality alone, for a specific lymph node station, and if this integrated approach can reduce the number of mediastinoscopies. A total of 113 patients with enlarged mediastinal lymph nodes (> or = 1 cm), who underwent both TBNA and PET scanning, were included. In 51 patients, histopathology, confirmed by surgical lymph node dissection, was compared with PET results and TBNA. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy to detect malignant lymphadenopathy was 68 (13/19), 89 (119/134), 46 (13/28), 95 (119/125) and 86% (132/152) for PET, respectively; 54% (6/11), 100 (53/53), 100 (6/6), 91 (53/58) and 92% (59/64), respectively for TBNA; and 100 (11/11), 94 (50/53), 79 (11/14), 100 (50/50) and 95 (61/64) for combined TBNA and PET, respectively. Combination of transbronchial needle aspiration and positron emission tomography has the potential to allow adequate mediastinal staging of nonsmall cell lung cancer with enlarged lymph nodes in most patients without the need for mediastinoscopy.  相似文献   
105.
106.
107.
108.
Clinicopathological and electron microscopical findings of eight cases of enzootic nasal adenocarcinoma of sheep, diagnosed solely in one big flock in Slovenia between years 2001 and 2003 are described. All affected sheep were female, their mean age was 4.5 ± 1.5 years and they either belonged to the Istrian pramenka breed (five sheep) or were crossbreeds (three sheep). Tumours that arose from the ethmoid area of the nasal cavity were unilateral in six cases (75%) and bilateral in two cases (25%). All tumours were classified as adenocarcinomas by histopathological examination and they displayed either a combination of tubular and papillary growth or less often solely tubular proliferation. No metastases were detected in regional lymph nodes, brain or other organs. Electron microscopical studies performed on the reprocessed paraffin‐embedded tissues revealed the presence of the virus‐like particles with an average diameter between 70 and 90 nm.  相似文献   
109.
110.
A new semi-empirical formula for the evaluation of (n,(3)He) reaction cross-sections at the energy of 14.6 and 20 MeV is presented. Formula was derived using the analytical expression for the evaluation of the (3)He spectrum within the frame of pre-equilibrium exciton model. The systematics obtained is compared with the empirical formula for the (n,(3)He) reaction cross-section.  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