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   1418610篇
  免费   107304篇
  国内免费   2679篇
耳鼻咽喉   19770篇
儿科学   47887篇
妇产科学   37497篇
基础医学   201025篇
口腔科学   36879篇
临床医学   124961篇
内科学   287887篇
皮肤病学   30701篇
神经病学   114101篇
特种医学   56798篇
外国民族医学   666篇
外科学   217197篇
综合类   28744篇
现状与发展   3篇
一般理论   513篇
预防医学   105910篇
眼科学   30951篇
药学   104417篇
  37篇
中国医学   2650篇
肿瘤学   79999篇
  2021年   10638篇
  2019年   11609篇
  2018年   16185篇
  2017年   12369篇
  2016年   13681篇
  2015年   15522篇
  2014年   21737篇
  2013年   32397篇
  2012年   45422篇
  2011年   48085篇
  2010年   28516篇
  2009年   27309篇
  2008年   45835篇
  2007年   49143篇
  2006年   48838篇
  2005年   48107篇
  2004年   46714篇
  2003年   45104篇
  2002年   43934篇
  2001年   65344篇
  2000年   67491篇
  1999年   57834篇
  1998年   17063篇
  1997年   15272篇
  1996年   15497篇
  1995年   14640篇
  1994年   13814篇
  1993年   12812篇
  1992年   45254篇
  1991年   44173篇
  1990年   42773篇
  1989年   40656篇
  1988年   37399篇
  1987年   36750篇
  1986年   34063篇
  1985年   32754篇
  1984年   24708篇
  1983年   20775篇
  1982年   12423篇
  1981年   11344篇
  1979年   21684篇
  1978年   15174篇
  1977年   12901篇
  1976年   12012篇
  1975年   12889篇
  1974年   14897篇
  1973年   14327篇
  1972年   13115篇
  1971年   11852篇
  1970年   11185篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
22.
Medullary thyroid carcinoma (MTC) is a rare form of thyroid cancer representing about 10% of all thyroid malignancies. It occurs mostly as a sporadic tumor or in association with autosomal dominant inherited cancer syndromes--multiple endocrine neoplasia (MEN) types 2A and 2B and familial MTC. Germline mutations in exons 8, 10, 11, 13, 14, 15 and 16 of the RET proto-oncogene are found in most of the familial cases. There are only a few published data reporting multiple germline mutations in the RET proto-oncogene. We have detected double germline mutations in 2 different exons on the same RET allele in two MEN 2 families. In the MEN 2A family, double germline mutation in exons 10 (Cys620Phe) and 13 (Tyr791Phe) was detected. In the MEN 2B family, beside the classical germline mutation in exon 16 (Met918Thr) a second germline mutation in exon 13 (Tyr791Phe) was found. This study revealed that MEN 2 syndromes can also be caused by double germline mutations in the RET proto-oncogene and these families can be added to small worldwide cohort of families with multiple germline mutations.  相似文献   
23.
24.
25.
26.
Infections due to Penicillium species other than P.marneffei are rare. We identified a boy with X-linked chronic granulomatous disease (X-CGD) with a pulmonary nodule and adjacent rib osteomyelitis caused by Penicillium piceum. The only sign of infection was an elevated sedimentation rate. P. piceum was isolated by fine needle aspirate and from excised infected tissues. Surgical removal and one year of voriconazole treatment were very well tolerated and led to complete recovery. Microbiological, microscopic and molecular studies support the fungal diagnosis. P. piceum should be considered as a relevant pathogen in immunocompromised patients.  相似文献   
27.
Abstract: Background: Fetal pulse oximetry improves the assessment of fetal well‐being during labor. The objective of this study was to evaluate women's satisfaction with their experience with this additional technology. Methods: We surveyed women participating in the FOREMOST trial, a randomized controlled trial comparing the addition of fetal pulse oximetry (FPO) to conventional cardiotocograph (CTG) monitoring (intervention group), versus CTG‐only (control group), in the presence of nonreassuring fetal status during labor. Our survey evaluated 3 aspects of women's experience: labor, fetal monitoring, and participation in the research. The survey was administered within a few days of giving birth and repeated 3 months later. Results: No differences were found between the intervention and control groups for women's evaluations of their labor, fetal monitoring, research, or overall experiences when surveyed on both occasions. Within each study group, a small but statistically significant decline occurred in women's scores for their experience of labor and overall experience from the initial survey close to the time of giving birth, to 3 months later. The magnitude of differences in responses over time was similar for the both groups. Women were more satisfied after a spontaneous or assisted vaginal birth than after cesarean section. Length of time the research midwife was present had a significant positive effect on women's ratings of their experience several days after giving birth (p = 0.006), but no effect at 3 months. Conclusions: The addition of fetal pulse oximetry for the assessment of fetal well‐being during labor did not affect childbearing women's perceptions of fetal monitoring or their labor. Women evaluated their experience in the research process positively overall. Small changes occurred in women's perception of their satisfaction over time. (BIRTH 33:2 June 2006)  相似文献   
28.
The objective of this study is to test the luminous efficiency functions V(lambda), V'(lambda), V(10)(lambda) and their linear combinations on the basis of a data set gained from a simulated mesopic night-time driving experiment. Another aim is to provide 'real-world' data for the 'X framework' or 'linear combination model', and to find out its limits in a practical situation. Human performance was measured by the reaction time method. Results show that the single parameter of the linear combination of photopic and scotopic luminous efficiency functions can be determined analytically with little variation for a given mesopic background luminance level and a given visual target colour, but the computation leads to considerable deviations comparing all three target colours (red, green and blue) used in the experiment. The conclusion for the given experimental conditions is that the single parameter of the linear combination model has an increasing deviation for lower background luminance levels.  相似文献   
29.
30.
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