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   103307篇
  免费   42678篇
  国内免费   125篇
耳鼻咽喉   1758篇
儿科学   5030篇
妇产科学   1101篇
基础医学   19027篇
口腔科学   5365篇
临床医学   15574篇
内科学   28317篇
皮肤病学   7994篇
神经病学   15909篇
特种医学   3033篇
外国民族医学   1篇
外科学   17607篇
综合类   240篇
一般理论   50篇
预防医学   6609篇
眼科学   1558篇
药学   7092篇
中国医学   1062篇
肿瘤学   8783篇
  2023年   123篇
  2022年   249篇
  2021年   1722篇
  2020年   5284篇
  2019年   11242篇
  2018年   10637篇
  2017年   11819篇
  2016年   12439篇
  2015年   12408篇
  2014年   12517篇
  2013年   13449篇
  2012年   5731篇
  2011年   5869篇
  2010年   9858篇
  2009年   6211篇
  2008年   3663篇
  2007年   2628篇
  2006年   2652篇
  2005年   2483篇
  2004年   2426篇
  2003年   2460篇
  2002年   2608篇
  2001年   1008篇
  2000年   877篇
  1999年   540篇
  1998年   409篇
  1997年   375篇
  1996年   301篇
  1995年   337篇
  1994年   280篇
  1993年   262篇
  1992年   187篇
  1991年   198篇
  1990年   167篇
  1989年   143篇
  1988年   152篇
  1987年   157篇
  1986年   144篇
  1985年   138篇
  1984年   152篇
  1983年   120篇
  1982年   176篇
  1981年   172篇
  1980年   154篇
  1979年   96篇
  1978年   103篇
  1977年   92篇
  1976年   74篇
  1975年   64篇
  1972年   67篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
The objective of this study was to evaluate the epidemiology, diagnosis, pathophysiology, and treatment of bone loss related to anorexia nervosa. Earlier onset and longer duration of anorexia nervosa are associated with more severe bone loss. Osteoporosis develops in 38 to 50% of cases. Bone mineral density measurement by dual-energy X-ray absorptiometry is useful for assessing bone mass, and bone marker assays provide information on bone turnover. Bone loss in anorexia nervosa is probably multifactoriel. Estrogen deficiency was long felt to be the major factor. However, in contrast to postmenopausal osteoporosis, bone loss associated with anorexia nervosa is related mainly to inadequate bone formation, with only a slight increase in bone resorption. This suggests a role for nutritional factors, such as disturbances in the growth hormone-somatomedin C axis (GH/IGF-I) related to malnutrition. The best treatment strategy for correcting bone mass in patients with anorexia nervosa is not agreed on. Resumption of menstrual cycles and weight gain seem necessary but not always sufficient. Studies found no benefits with estrogen therapy, but this was usually given as estrogen–progestin contraceptives. No vast studies evaluating hormone replacement therapy have been reported. Bone formation enhancers such as IGF-I seem to provide the best results, most notably when used in combination with estrogens. This suggests that complex treatment strategies combining bone formation enhancers and bone resorption inhibitors may deserve evaluation.  相似文献   
112.
Two embryonal CNS tumors, atypical teratoid/rabdoid tumor (AT/RT) and primitive neuroectodermal tumor (PNET), may be confused with each other and misdiagnosed. Here we report an infant with a congenital supratentorial tumor, which was detected by fetal MRI at 37 weeks gestation. On routine histological examination, the tumor was composed mainly of small undifferentiated cells, among which many rhabdoid cells and occasional sickle‐shaped embracing cells were observed. No mesenchymal or epithelial areas were evident. Our impression was that the tumor was an atypical example of AT/RT. Immunohistochemically, almost all the tumor cells were strongly positive for vimentin. However, epithelial membrane antigen was notably negative, and most of the tumor cell nuclei were clearly positive for INI1. In addition, many tumor cells were positive for neurofilament protein. There were also occasional small areas containing many tumor cells positive for glial fibrillary acidic protein. Finally, a diagnosis of PNET, with a rhabdoid phenotype and expression of neuronal and glial markers, was made. In the present case, application of INI1 immunostaining was very helpful for distinguishing PNET from AT/RT.  相似文献   
113.
114.
115.
116.
The goal of endoscopic mucosal resection (EMR) is to allow the endoscopist to obtain tissue or resect lesions not previously amenable to standard biopsy or excisional techniques and to remove malignant lesions without open surgery. In this article, we describe the results of conventional EMR and EMR using an insulation‐tipped (IT) electrosurgical knife (submucosal dissection method) for large colorectal mucosal neoplasms and discuss the problems and future prospects of these procedures. At present, conventional EMR is much more feasible than EMR using IT‐knife from the perspectives of time, money, complication, and organ preservation. However, larger lesions tend to be resected in a piecemeal fashion; and it is difficult to confirm whether EMR has been complete. For accurate histopathological assessment of the resected specimen en bloc EMR is desirable although further experience is needed to establish its safety and efficacy. Further improvements of in EMR with special knife techniques are required to simply and safely remove large colorectal neoplasms.  相似文献   
117.
Background: Intravenous infusion of lidocaine decreases postoperative pain and speeds the return of bowel function. The authors therefore tested the hypothesis that perioperative lidocaine infusion facilitates acute rehabilitation protocol in patients undergoing laparoscopic colectomy.

Methods: Forty patients scheduled to undergo laparoscopic colectomy were randomly allocated to receive intravenous lidocaine (bolus injection of 1.5 mg/kg lidocaine at induction of anesthesia, then a continuous infusion of 2 mg [middle dot] kg-1 [middle dot] h-1 intraoperatively and 1.33 mg [middle dot] kg-1 [middle dot] h-1 for 24 h postoperatively) or an equal volume of saline. All patients received similar intensive postoperative rehabilitation. Postoperative pain scores, opioid consumption, and fatigue scores were measured. Times to first flatus, defecation, and hospital discharge were recorded. Postoperative endocrine (cortisol and catecholamines) and metabolic (leukocytes, C-reactive protein, and glucose) responses were measured for 48 h. Data (presented as median [25-75% interquartile range], lidocaine vs. saline groups) were analyzed using Mann-Whitney tests. P < 0.05 was considered statistically significant.

Results: Patient demographics were similar in the two groups. Times to first flatus (17 [11-24] vs. 28 [25-33] h; P < 0.001), defecation (28 [24-37] vs. 51 [41-70] h; P = 0.001), and hospital discharge (2 [2-3] vs. 3 [3-4] days; P = 0.001) were significantly shorter in patients who received lidocaine. Lidocaine significantly reduced opioid consumption (8 [5-18] vs. 22 [14-36] mg; P = 0.005) and postoperative pain and fatigue scores. In contrast, endocrine and metabolic responses were similar in the two groups.  相似文献   

118.
119.
120.
This paper considers the immediate post‐traumatic reactions of rescue personnel who were exposed to the Hilton Hotel bombing in Sinai. The entire rescue personnel (n = 26) were assessed and separated into two groups on the basis of previous exposure to the same type of trauma. The results suggest that among rescue personnel, those with previous exposure had a lower level of post‐traumatic symptoms than those who were being exposed for the first time. This supports the hypothesis that previous exposure to the same type of trauma has an immunizing effect for subsequent same type of traumatic event among rescue personnel. Copyright © 2005 John Wiley & Sons, Ltd.  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