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   1034409篇
  免费   63927篇
  国内免费   2410篇
耳鼻咽喉   16692篇
儿科学   33172篇
妇产科学   31859篇
基础医学   151858篇
口腔科学   28012篇
临床医学   80986篇
内科学   210335篇
皮肤病学   25217篇
神经病学   80969篇
特种医学   41961篇
外国民族医学   336篇
外科学   162736篇
综合类   19499篇
一般理论   251篇
预防医学   69577篇
眼科学   25233篇
药学   68579篇
中国医学   1851篇
肿瘤学   51623篇
  2018年   9448篇
  2016年   8045篇
  2015年   11873篇
  2014年   16109篇
  2013年   24108篇
  2012年   29380篇
  2011年   30860篇
  2010年   20287篇
  2009年   19576篇
  2008年   29906篇
  2007年   31427篇
  2006年   31985篇
  2005年   31111篇
  2004年   29750篇
  2003年   27477篇
  2002年   25739篇
  2001年   42230篇
  2000年   43413篇
  1999年   37212篇
  1998年   11120篇
  1997年   10279篇
  1996年   10558篇
  1995年   10063篇
  1994年   9740篇
  1993年   9143篇
  1992年   29855篇
  1991年   28393篇
  1990年   27736篇
  1989年   26504篇
  1988年   24610篇
  1987年   24282篇
  1986年   23284篇
  1985年   22048篇
  1984年   16801篇
  1983年   14296篇
  1982年   9064篇
  1981年   7941篇
  1979年   15478篇
  1978年   11226篇
  1977年   9416篇
  1976年   8820篇
  1975年   9742篇
  1974年   11498篇
  1973年   11031篇
  1972年   10354篇
  1971年   9520篇
  1970年   9142篇
  1969年   8737篇
  1968年   8256篇
  1967年   7670篇
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
21.
22.
23.
Sniff nasal inspiratory pressure (SNIP) measurement is a volitional noninvasive assessment of inspiratory muscle strength. A maximum of 10 sniffs is generally used. The purpose of the present study was to investigate whether the maximum SNIP improved after the tenth sniff. In total, 20 healthy volunteers and 305 patients with various neuromuscular and lung diseases were encouraged to perform 40 and 20 sniffs, respectively. The best SNIP among the first 10 sniffs was lower than the best SNIP among the next 10 sniffs in the healthy volunteers and patients. The SNIP improvement after the twentieth sniff was marginal. In conclusion, a learning effect persists after the tenth sniff. The current authors suggest using 10 additional sniffs when the best result of the first 10 sniffs is slightly below normal, or when sniff nasal inspiratory pressure is used to monitor a progressive decline in inspiratory muscle strength.  相似文献   
24.
25.
26.
27.
28.
29.
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   
30.
BACKGROUND: Three dimensional skin equivalents are widely used in dermatopharmacological and toxicological studies and as autologous transplants in wound healing. In pharmacology, there is tremendous need for monitoring the response of engineered skin equivalents to external treatment. Transplantation of skin equivalents for wound healing requires careful verification of their quality prior to transplantation. Optical coherence tomography (OCT) is a non-contact, non-destructive imaging technique for living tissues offering the potential to fulfill these needs. This work presents an analysis of OCT for high-resolution monitoring of skin equivalents at different stages during the culture process. METHODS: We developed a high-resolution OCT imaging setup based on a commercially available OCT system. A broadband femtosecond laser light source replaces the original superluminescence diode. Tomograms of living skin equivalents were recorded with an axial resolution of 3 mum and correlated with histology and immunofluorescence images. Comparison with standard low-resolution OCT is presented to emphasize the advantages of high-resolution OCT for this application. RESULTS: OCT is particularly able to distinguish between different layers of skin equivalents including stratum corneum, epidermal and dermal layer as well as the basement membrane zone. The high-resolution OCT scans correlate closely with two key benchmarks, histology and immunofluorescence imaging. CONCLUSIONS: This study clearly demonstrates the benefits of high-resolution OCT for identifying living tissue structure and morphology. Compared with the current gold standard histology, OCT offers non-destructive tissue imaging, enabling high-resolution evaluation of living tissue morphology and structure as it evolves.  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