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   984篇
  免费   50篇
  国内免费   2篇
耳鼻咽喉   5篇
儿科学   62篇
妇产科学   3篇
基础医学   100篇
口腔科学   22篇
临床医学   51篇
内科学   159篇
皮肤病学   37篇
神经病学   38篇
特种医学   57篇
外科学   115篇
综合类   283篇
预防医学   53篇
眼科学   1篇
药学   17篇
  1篇
肿瘤学   32篇
  2021年   9篇
  2020年   8篇
  2019年   11篇
  2018年   10篇
  2017年   9篇
  2016年   6篇
  2015年   26篇
  2014年   27篇
  2013年   34篇
  2012年   34篇
  2011年   29篇
  2010年   69篇
  2009年   50篇
  2008年   52篇
  2007年   54篇
  2006年   56篇
  2005年   38篇
  2004年   53篇
  2003年   29篇
  2002年   36篇
  2001年   33篇
  2000年   33篇
  1999年   25篇
  1998年   30篇
  1997年   31篇
  1996年   32篇
  1995年   18篇
  1994年   22篇
  1993年   9篇
  1992年   12篇
  1991年   4篇
  1990年   8篇
  1989年   10篇
  1988年   7篇
  1987年   6篇
  1986年   11篇
  1985年   7篇
  1984年   5篇
  1983年   6篇
  1982年   8篇
  1981年   7篇
  1980年   7篇
  1979年   5篇
  1978年   9篇
  1977年   4篇
  1976年   7篇
  1975年   3篇
  1974年   3篇
  1973年   5篇
  1918年   3篇
排序方式: 共有1036条查询结果,搜索用时 15 毫秒
1.
BACKGROUND: The present study was aimed to define the gender ratio, familial occurrence, age of onset, precipitating factors, clinical types, nail and joint involvement of psoriasis in childhood and adolescence in Turkey. METHODS: A total of 61 children with psoriasis under 18 years old were evaluated retrospectively, for age, gender, age of disease onset, family history, concomitant disease, the clinical type of psoriasis, clinical localization, nail and joint involvement and treatment modalities. RESULTS: Of the patients, 23 (37.70%) were boys and 38 (62.30%) were girls. Mean age was 9.28 +/- 4.02 years in girls and 11.18 +/- 3.85 years in boys (9.96 +/- 4.03 years in all children). Mean age at the onset of the disease was 6.81 +/- 4.11 years in girls and 7.03 +/- 4.28 years in boys (6.89 +/- 4.14 years in all patients). In 14 (23%) cases, a positive family history was detected. The most frequent probable triggering factors were upper respiratory tract infections (14.8%) and positive throat culture for A group ss-hemolytic streptococcus (21.3%). Frequency of emotional stress and psychiatric morbidity were 54% and 9.8%, respectively. The most frequent localizations at onset were trunk (44.3%), extremities (54.0%), and scalp (36.0%). Three children (4.9%) had a history of dissemination from psoriatic diaper rash. In total, 51 (83.6%) patients presented with psoriasis vulgaris, eight (13.1%) with generalized pustular psoriasis, and the remaining two (3.3%) with erythrodermic psoriasis. CONCLUSION: The incidence of psoriasis among dermatological patients in childhood and adolescence was 3.8%. The disease tends to appear earlier in girls than boys. The authors suggested that stress and upper respiratory infections are the most important triggering factors in childhood and adolescence psoriasis.  相似文献   
2.
3.
4.
5.
6.
7.
8.
mRNAs encoding five genetically distinct muscarinic ACh receptors are present in the CNS. Because of their pharmacological similarities, it has not been possible to detect the individual encoded proteins; thus, their physiological functions are not well defined. To characterize the family of proteins, a panel of subtype-selective antibodies was generated against recombinant muscarinic receptor proteins and shown to bind specifically to each of the cloned receptors. Using immunoprecipitation, three receptor proteins (m1, m2, and m4) accounted for the vast majority of the total solubilized muscarinic binding sites in rat brain. These receptor subtypes had marked differences in regional and cellular localization as shown by immunocytochemistry. The m1-protein was present in cortex and striatum and was localized to cell bodies and neurites, consistent with its role as a major postsynaptic muscarinic receptor. The m2-receptor protein was abundant in basal forebrain, scattered striatal neurons, mesopontine tegmentum, and cranial motor nuclei; this distribution is similar to that of cholinergic neurons and suggests that m2 is an autoreceptor. However, m2 was also present in noncholinergic cortical and subcortical structures, providing evidence that this subtype may presynaptically modulate release of other neurotransmitters and/or function postsynaptically. The m4-receptor was enriched in neostriatum, olfactory tubercle, and islands of Calleja, indicating an important role in extrapyramidal function. These results clarify the roles of these genetically defined receptor proteins in cholinergic transmission in brain.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
9.
Traditional experimental methods are unable to study the kinematics of whole lumbar spine specimens under physiologic compressive preloads because the spine without active musculature buckles under just 120 N of vertical load. However, the lumbar spine can support a compressive load of physiologic magnitude (up to 1200 N) without collapsing if the load is applied along a follower load path. This study tested the hypothesis that the load-displacement response of the lumbar spine in flexion-extension is affected by the magnitude of the follower preload and the follower preload path. Twenty-one fresh human cadaveric lumbar spines were tested in flexion-extension under increasing compressive follower preload applied along two distinctly different optimized preload paths. The first (neutral) preload path was considered optimum if the specimen underwent the least angular change in its lordosis when the full range of preload (0-1200 N) was applied in its neutral posture. The second (flexed) preload path was optimized for an intermediate specimen posture between neutral and full flexion. A twofold increase in flexion stiffness occurred around the neutral posture as the preload was increased from 0 to 1200 N. The preload magnitude (400 N and larger) significantly affected the range of motion (ROM), with a 25% decrease at 1200 N preload applied along the neutral path. When the preload was applied along a path optimized for an intermediate forward-flexed posture, only a 15% decrease in ROM occurred at 1200 N. The results demonstrate that whole lumbar spine specimens can be subjected to compressive follower preloads of in vivo magnitudes while allowing physiologic mobility under flexion-extension moments. The optimized follower preload provides a method to simulate the resultant vector of the muscles that allow the spine to support physiologic compressive loads induced during flexion-extension activities.  相似文献   
10.
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