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   2692272篇
  免费   189047篇
  国内免费   7831篇
耳鼻咽喉   35684篇
儿科学   87798篇
妇产科学   74082篇
基础医学   378744篇
口腔科学   73332篇
临床医学   240893篇
内科学   537243篇
皮肤病学   65231篇
神经病学   222250篇
特种医学   102375篇
外国民族医学   737篇
外科学   398116篇
综合类   50933篇
现状与发展   5篇
一般理论   983篇
预防医学   209910篇
眼科学   59467篇
药学   196129篇
  8篇
中国医学   5719篇
肿瘤学   149511篇
  2021年   21781篇
  2019年   22669篇
  2018年   32756篇
  2017年   24775篇
  2016年   28339篇
  2015年   31868篇
  2014年   43058篇
  2013年   64271篇
  2012年   87033篇
  2011年   91756篇
  2010年   54575篇
  2009年   51714篇
  2008年   84803篇
  2007年   89968篇
  2006年   91363篇
  2005年   87235篇
  2004年   83849篇
  2003年   80737篇
  2002年   77765篇
  2001年   130364篇
  2000年   133482篇
  1999年   112233篇
  1998年   31638篇
  1997年   28140篇
  1996年   28461篇
  1995年   27589篇
  1994年   25234篇
  1993年   23566篇
  1992年   86275篇
  1991年   82620篇
  1990年   79853篇
  1989年   76963篇
  1988年   70384篇
  1987年   68866篇
  1986年   64453篇
  1985年   61365篇
  1984年   45591篇
  1983年   38473篇
  1982年   22768篇
  1981年   20254篇
  1979年   39740篇
  1978年   27982篇
  1977年   23814篇
  1976年   22012篇
  1975年   23393篇
  1974年   27580篇
  1973年   26216篇
  1972年   24548篇
  1971年   22712篇
  1970年   20913篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
91.
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   
92.
93.
94.
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   
95.
96.
97.
98.
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   
99.
100.
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