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   2441篇
  免费   220篇
  国内免费   11篇
耳鼻咽喉   13篇
儿科学   110篇
妇产科学   47篇
基础医学   335篇
口腔科学   22篇
临床医学   374篇
内科学   479篇
皮肤病学   44篇
神经病学   160篇
特种医学   60篇
外科学   247篇
综合类   34篇
一般理论   4篇
预防医学   387篇
眼科学   96篇
药学   140篇
中国医学   3篇
肿瘤学   117篇
  2023年   29篇
  2022年   26篇
  2021年   75篇
  2020年   55篇
  2019年   67篇
  2018年   54篇
  2017年   60篇
  2016年   69篇
  2015年   69篇
  2014年   85篇
  2013年   121篇
  2012年   187篇
  2011年   193篇
  2010年   101篇
  2009年   88篇
  2008年   146篇
  2007年   156篇
  2006年   140篇
  2005年   108篇
  2004年   120篇
  2003年   123篇
  2002年   87篇
  2001年   42篇
  2000年   30篇
  1999年   29篇
  1998年   23篇
  1997年   13篇
  1996年   12篇
  1995年   16篇
  1994年   15篇
  1993年   11篇
  1992年   24篇
  1991年   23篇
  1990年   20篇
  1989年   15篇
  1988年   19篇
  1987年   18篇
  1986年   15篇
  1985年   13篇
  1984年   14篇
  1983年   10篇
  1982年   11篇
  1981年   9篇
  1979年   9篇
  1977年   8篇
  1976年   7篇
  1974年   10篇
  1973年   14篇
  1972年   8篇
  1970年   7篇
排序方式: 共有2672条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Journal of Behavioral Medicine - Understanding associations between mothers’ and children’s physical activity and sedentary behavior on more fine-grained timescales can provide insights...  相似文献   
5.
A 13 year old Asian girl presenting with apparent hysterical paralysis and subsequent rapid cycling bipolar mood disorder was found to have biochemical evidence of pseudohypoparathyroidism type II. The mood disorder responded to treatment of the pseudohypoparathyroidism with a vitamin D analogue. Investigation of her parents and siblings showed phenotypes consistent with two distinct types of pseudohypoparathyroidism (type I and type II) in different family members.  相似文献   
6.
The influence of the thermal environment on evaporation and heat loss from patients with severe burns treated by exposure has been studied. Simple heat transfer equations can be used to predict changes resulting from alterations in environmental conditions and these have been tested using phantoms. The method relies upon the derivation of surface diffusion resistances to describe the moisture properties of burn wounds. Clinical measurements revealed wide variations in evaporation rates and diffusion resistances for different wounds. Evaporation rates changed by less than 30 per cent during the first 5-6 days following injury, after which evaporation from partial skin thickness wounds gradually fell whereas that from full skin thickness wounds tended to remain higher. Raising ambient temperature can compensate for increased evaporation heat losses. Patients can be treated at ambient temperatures of 32-35 degrees C in the intensive care room with a specially designed airflow system. However, raising the temperatures of standard wards with no special airflow or temperature control facilities often caused patients to sweat, further increasing heat loss.  相似文献   
7.
8.
BACKGROUND: Research has sought to understand how environmental factors influence adolescent physical activity, yet little is known about where and with whom adolescents are physically active. PURPOSE: This study used electronic ecological momentary assessment (e.EMA) to map the social and physical contexts of exercise and walking across adolescence. Differences in physical activity contexts by gender, grade in school, day of the week, and season were examined. METHODS: Twice a year between 9th and 12th grade, 502 adolescents (51% female) of mixed ethnicity (55% White) participated in 4-day e.EMA intervals (Thursday-Sunday) where their primary activity (e.g., exercise, TV, homework), social company (e.g., friends, family, class), and physical location (e.g., home, school, outdoors) were assessed every 30 (+/-10) min during waking hours. RESULTS: Overall, greater proportions of exercise and walking were reported with friends, outdoors, and at school. However, boys were more likely to report exercising and walking in outdoor locations than girls. Exercising with classmates, family, and at school decreased across high school. Walking with family, friends, and outdoors also decreased. On weekdays compared to weekends, students reported a greater proportion of their exercise and walking at school. Students were more likely to report exercising and walking outdoors in the fall and the spring than in the winter. CONCLUSION: e.EMA showed that the social and physical contexts of adolescent exercise and walking vary as a function of gender, grade in school, day of the week, and season. Understanding the contexts of physical activity during the high school years can be helpful in designing interventions during adolescence.  相似文献   
9.
The renin-angiotensin system (RAS) is essential for blood pressure control and water-electrolyte balance. Until the discovery of the renin receptor, renin was believed to be mainly a circulating enzyme with a unique function, the cleavage of angiotensinogen. We report a unique mutation in the renin receptor gene (ATP6AP2) present in patients with X-linked mental retardation and epilepsy (OMIM no. 300423), but absent in 1200 control X-chromosomes. A silent mutation (c.321C>T, p.D107D) residing in a putative exonic splicing enhancer site resulted in inefficient inclusion of exon 4 in 50% of renin receptor mRNA, as demonstrated by quantitative RT-PCR. Analysis of membrane associated-receptor molecular forms showed the presence of full-length and truncated proteins in the patient. Functional analysis demonstrated that the mutated receptor could bind renin and increase renin catalytic activity, similar to the wild-type receptor, but resulted in a modest and reproducible impairment of ERK1/2 activation. Thus, our findings confirm the importance of the RAS in cognitive processes and indicate a novel specific role for the renin receptor in cognitive functions and brain development.  相似文献   
10.
The presence of endotoxin (detected by the Limulus amebocyte lysate assay) was compared to the presence of viable Haemophilus influenzae and Moraxella catarrhalis (detected by PCR) in 106 middle-ear effusions from pediatric patients with chronic otitis media. Endotoxin was found in 81 of the 106 specimens. Of these 81 specimens, 66 (81.5%) also tested positive for one or both of the gram-negative bacteria H. influenzae and M. catarrhalis. The data suggest that viable gram-negative bacteria, detectable by PCR but often undetectable by culture, may be the source of endotoxin in middle-ear effusions.  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