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   12913篇
  免费   998篇
  国内免费   24篇
耳鼻咽喉   83篇
儿科学   505篇
妇产科学   430篇
基础医学   1458篇
口腔科学   216篇
临床医学   2403篇
内科学   1861篇
皮肤病学   217篇
神经病学   1365篇
特种医学   301篇
外科学   1203篇
综合类   226篇
一般理论   28篇
预防医学   1782篇
眼科学   174篇
药学   863篇
  1篇
中国医学   48篇
肿瘤学   771篇
  2023年   64篇
  2022年   90篇
  2021年   221篇
  2020年   158篇
  2019年   221篇
  2018年   279篇
  2017年   248篇
  2016年   243篇
  2015年   266篇
  2014年   368篇
  2013年   551篇
  2012年   868篇
  2011年   917篇
  2010年   511篇
  2009年   462篇
  2008年   815篇
  2007年   878篇
  2006年   799篇
  2005年   788篇
  2004年   840篇
  2003年   733篇
  2002年   707篇
  2001年   171篇
  2000年   176篇
  1999年   161篇
  1998年   150篇
  1997年   138篇
  1996年   114篇
  1995年   107篇
  1994年   104篇
  1993年   73篇
  1992年   101篇
  1991年   109篇
  1990年   88篇
  1989年   85篇
  1988年   82篇
  1987年   80篇
  1986年   70篇
  1985年   70篇
  1984年   65篇
  1983年   77篇
  1982年   71篇
  1981年   69篇
  1980年   61篇
  1979年   57篇
  1978年   63篇
  1977年   45篇
  1976年   47篇
  1975年   44篇
  1974年   52篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
2.
3.
4.
Hydration and Cognitive Function in Children   总被引:3,自引:0,他引:3  
Adequate fluid intake is critical for survival. While adults are at liberty to drink fluids as wanted, children and infants are dependent upon caregivers for food and fluid. Children are at greater risk for dehydration than adults due to their higher surface-to-mass ratio. Additionally, children have different thirst sensitivities and body cooling mechanisms than adults. Children differ from adults in total body water content, and boys and girls differ in body water content with maturation. Research in young adults shows that mild dehydration corresponding to only 1% to 2% of body weight loss can lead to significant impairment in cognitive function. Dehydration in infants is associated with confusion, irritability, and lethargy; in children, it may produce decrements in cognitive performance.  相似文献   
5.
Fibroblasts incorporated within collagen gels induce a cell-mediated contraction of the gel to form a three-dimensional, tissue-like structure by a mechanism thought to mimic wound contraction in vivo . In this study a gel contraction model was used to investigate the ability of fibroblasts derived from adult gingiva, adult skin and fetal skin to organise a collagen matrix. In addition the effects of interleukin-1β (IL-1β) on the contraction process was also investigated. Over the concentration range 5-50 U/ml, IL-1β induced a statistically significant inhibition of gel contraction in all fibroblast cell types ( P <0.05), although fetal fibroblasts appeared least responsive and gingival fibroblasts most responsive to the inhibitory effects of this cytokine. Comparison of gel contraction by the different fibroblast strains indicated that fetal and gingival fibroblasts shared similar contraction kinetics. For the adult skin fibroblasts, three of five strains studied showed significantly diminished levels of gel contraction compared to fetal and gingival cells. This apparent difference in fibroblast phenotype may, at least in part, explain the fetal-like wound healing pattern seen in the oral mucosa.  相似文献   
6.
7.
The long-held belief that degeneration of the cholinergic basal forebrain was central to Alzheimer's disease (AD) pathogenesis and occurred early in the disease process has been questioned recently. In this regard, changes in some cholinergic basal forebrain (CBF) markers (e.g. the high affinity trkA receptor) but not others (e.g., cortical choline acetyltransferase [ChAT] activity, the number of ChAT and vesicular acetylcholine transporter-immunoreactive neurons) suggest specific phenotypic changes, but not frank neuronal degeneration, early in the disease process. The present study examined the expression of the low affinity p75 neurotrophin receptor (p75(NTR)), an excellent marker of CBF neurons, in postmortem tissue derived from clinically well-characterized individuals who have been classified as having no cognitive impairment (NCI), mild cognitive impairment (MCI), and mild AD. Relative to NCI individuals, a significant and similar reduction in the number of nucleus basalis p75(NTR)-immunoreactive neurons was seen in individuals with MCI (38%) and mild AD (43%). The number of p75(NTR)-immunoreactive nucleus basalis neurons was significantly correlated with performance on the Mini-Mental State Exam, a Global Cognitive Test score, as well as some individual tests of working memory and attention. These data, together with previous reports, support the concept that phenotypic changes, but not frank neuronal degeneration, occur early in cognitive decline. Although there was no difference in p75(NTR) CBF cell reduction between MCI and AD, it remains to be determined whether these findings lend support to the hypothesis that MCI is a prodromal stage of AD.  相似文献   
8.
9.
梁素娥 《现代医院》2007,7(Z2):83-84
目的 保持皮肤清洁,使病人身心舒适;维持病人皮肤完整性,治疗或预防皮肤并发症.方法 ①大小便失禁病人皮肤完整的床上擦浴,bid,排便后及时清洗,用电吹风或红外线照射,保持会阴部、尾骶部皮肤干燥;应用一次性尿垫、阴茎套、留置导尿管等辅助工具接尿;②褥疮护理使用气垫床,翻身防褥疮护理,q2h,对褥疮创面给予换药、湿润烧伤膏外敷,qd;③外阴炎给予达克宁霜或康纳乐霜外涂,tid.结果 入院时皮肤完好的320例病人褥疮发生率为0.5%,皮肤炎发生率为0.85%,尿路感染发生率为1.5%;50例皮肤炎病人全部治愈,86例带入院褥疮治愈率为93%.结论 对大小便失禁的病人实施良好的皮肤护理,可促进病人舒适,维持病人皮肤完整性,治疗和预防皮肤并发症的发生.  相似文献   
10.
Aims: Studies conducted in first‐episode psychosis (FEP) samples avoid many biases. However, very few studies are based on epidemiological cohorts treated in specialized FEP services. The aim of this file audit study was to examine premorbid and baseline characteristics of a large epidemiological sample of FEP. Methods: File audit study of all patients admitted to the Early Psychosis Prevention and Intervention Centre between 1998 and 2000 using a specialized questionnaire. Results: There were 661 patient files included in the study. Premorbid evaluation revealed high rates of substance use disorder (74.1%), history of psychiatric disorder (47.5%), past traumatic events (82.7%) suicide attempts (14.3%) and family history of psychiatric illness (55.6%). Baseline characteristics revealed high intensity of illness (mean CGI 5.5), high prevalence of lack of insight (62%) and high rate of comorbidity (70%). Conclusion: High rates of traumatic events or episodes of mental illness before treatment for FEP must be considered when designing treatment approaches because a too narrow focus on positive psychotic symptoms will inevitably lead to incomplete treatment. Additionally, early intervention programmes need sufficient range of resources to address the multiple challenges presented by FEP patients such as high severity of illness, comorbidities and functional impairment. Finally, observation of an important degree of functional impairment despite short duration of untreated psychosis suggests that while early detection of FEP is a necessary step in early intervention, it may not be sufficient to improve functional recovery in psychosis and that efforts aimed at identifying people during the prodromal phase of psychotic disorders should be pursued.  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