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   18837篇
  免费   1994篇
  国内免费   290篇
耳鼻咽喉   100篇
儿科学   592篇
妇产科学   247篇
基础医学   1785篇
口腔科学   385篇
临床医学   1654篇
内科学   2897篇
皮肤病学   172篇
神经病学   1193篇
特种医学   334篇
外国民族医学   2篇
外科学   917篇
综合类   2083篇
一般理论   3篇
预防医学   5642篇
眼科学   239篇
药学   1542篇
  10篇
中国医学   274篇
肿瘤学   1050篇
  2024年   9篇
  2023年   414篇
  2022年   388篇
  2021年   743篇
  2020年   873篇
  2019年   859篇
  2018年   695篇
  2017年   791篇
  2016年   765篇
  2015年   830篇
  2014年   1258篇
  2013年   1785篇
  2012年   1325篇
  2011年   1319篇
  2010年   1094篇
  2009年   1023篇
  2008年   966篇
  2007年   1009篇
  2006年   804篇
  2005年   591篇
  2004年   516篇
  2003年   408篇
  2002年   373篇
  2001年   367篇
  2000年   275篇
  1999年   213篇
  1998年   179篇
  1997年   154篇
  1996年   141篇
  1995年   113篇
  1994年   108篇
  1993年   97篇
  1992年   103篇
  1991年   84篇
  1990年   54篇
  1989年   42篇
  1988年   47篇
  1987年   30篇
  1986年   45篇
  1985年   47篇
  1984年   28篇
  1983年   20篇
  1982年   26篇
  1981年   22篇
  1980年   25篇
  1979年   13篇
  1978年   10篇
  1977年   18篇
  1976年   6篇
  1975年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
刘刚军    马丽    乔慧   《现代预防医学》2022,(24):4442-4445
目的 这项研究在于掌握宁夏农村地区学龄儿童卫生服务利用现状及卫生服务利用公平性的动态变化,为政府部门了解学龄儿童卫生服务利用情况提供数据支撑,为学龄儿童健康促进方案的科学发展提供基础依据。方法 利用“农村居民家庭卫生健康询问调查”2009年开始的基准数据,以及2011、2012、2015和2019年随访调查数据,最终选取年龄为7~12岁并且调查时在家常住(指在家居住时间≥0.5年)的学龄儿童作为本次研究对象。利用χ2检验对不同收入水平组间的率进行比较,使用集中指数(concentration index,CI)衡量不同收入水平群体间卫生服务利用公平性的变化。结果 两周就诊情况经趋势χ2检验显示不同调查年份之间差异有统计学意义(χ2 = 16.189,P = 0.004);χ2检验显示,不同收入水平的人群在2011年(χ2 = 13.416,P = 0.028)、2012年(χ2 = 22.489,P = 0.009)存在统计上的显著差异。其他四年CI均为正值,只有2011年CI为负值,但是比较五次调查CI的绝对值,可以发现其保持下降。两周患病未就诊情况经趋势χ2检验显示不同调查年份之间差异有统计学意义(χ2 = 4.905,P = 0.027)。CI值均为负值,并且绝对值表现为下降态势,不公平程度正在减弱。住院情况经趋势χ2检验显示不同调查年份之间差异没有统计学意义(χ2 = 0.047,P = 0.829)。CI值均为正值,说明卫生服务利用偏向于高收入人群,绝对值整体上是下降的,表现为齿状波动样。结论 在农村学龄儿童中,卫生服务利用水平较低,五次调查发现不公平程度正在逐渐减小。  相似文献   
2.
IntroductionThe main aim of this study was to assess the utility of differential white cell count and cell population data (CPD) for the detection of COVID-19 in patients admitted for community-acquired pneumonia (CAP) of different etiologies.MethodsThis was a multicenter, observational, prospective study of adults aged ≥18 years admitted to three teaching hospitals in Spain from November 2019 to November 2021 with a diagnosis of CAP. At baseline, a Sysmex XN-20 analyzer was used to obtain detailed information related to the activation status and functional activity of white cells.ResultsThe sample was split into derivation and validation cohorts of 1065 and 717 patients, respectively. In the derivation cohort, COVID-19 was confirmed in 791 patients and ruled out in 274 patients, with mean ages of 62.13 (14.37) and 65.42 (16.62) years, respectively (p < 0.001). There were significant differences in all CPD parameters except MO-Y. The multivariate prediction model showed that lower NE-X, NE-WY, LY-Z, LY-WY, MO-WX, MO-WY, and MO-Z values and neutrophil-to-lymphocyte ratio were related to COVID-19 etiology with an AUC of 0.819 (0.790, 0.846). No significant differences were found comparing this model to another including biomarkers (p = 0.18).ConclusionsAbnormalities in white blood cell morphology based on a few cell population data values as well as NLR were able to accurately identify COVID-19 etiology. Moreover, systemic inflammation biomarkers currently used were unable to improve the predictive ability. We conclude that new peripheral blood biomarkers can help determine the etiology of CAP fast and inexpensively.  相似文献   
3.
[摘要] 目的 了解开封地区无偿献血人群HIV感染状况和流行特征,为献血招募、降低输血途径传播HIV及确保临床用血安全提供依据。方法 采用2种不同厂家ELISA试剂和核酸试剂对2013—2020年间539 015例献血者标本进行HIV初筛,结果呈阳性者送开封市疾病预防控制中心确证实验室确证。分析和比较不同特征献血人群HIV感染状况和流行特征。结果 539 015例献血者标本中,HIV初筛阳性120例(2.23/万),经确证HIV阳性53例(0.98/万)。2013—2020年男性献血者HIV阳性率和献血者HIV总阳性率均呈下降趋势。确证后标本HIV阳性率男性(1.34/万)高于女性(0.39/万),首次献血(3.17/万)高于重复献血(0.38/万),全血(1.05/万)高于单采血小板(0.22/万),外地户籍(2.39/万)高于本市户籍(0.91/万),差异均有统计学意义(P均<0.05)。26~35岁(1.52/万)HIV阳性率高于其他年龄段,差异有统计学意义(P<0.05)。53例HIV阳性献血者中,单纯HIV阳性41例(77.36%),HIV合并其他病原体感染者12例(22.64%)。结论 2013年以来开封地区献血人群HIV阳性率呈下降趋势,HIV感染者主要发生于青年男性、捐献全血、首次献血、低学历、公司职员及外地户籍献血人群。加强献血前征询及建立低危/稳定的献血队伍可降低/避免输血传播HIV风险。  相似文献   
4.
5.
目的 探讨贵州农村老年人社会支持与认知功能的联系,并分析焦虑和睡眠在其间的中介作用,为认知功能减退及痴呆的行为预防提供科学参考。方法 于2019年7—8月采用多阶段整群随机抽样方法选取贵州农村≥60岁者共1 615人作为调查对象,采用自编一般情况调查表、社会支持评定量表(SSRS)、简易智力状态检测量表(MMSE)、阿森斯失眠量表(AIS)、焦虑状态量表(GAD - 2)进行问卷调查。采用结构方程模型探讨老年人社会支持水平、焦虑、睡眠及认知功能四者间的联系。结果 1 615名老年人认知功能得分为(21.09±5.21)分,女性(t = 16.559,P<0.001)、少数民族(t = 2.425,P = 0.015)、非在婚(t = 8.954,P<0.001)、年龄越大(F = 42.638,P<0.001)、文化程度越低(F = 174.167,P<0.001)的老年人认知功能相对较差。MMSE得分与GAD - 2、AIS得分均呈负相关,与SSRS得分呈正相关(r = - 0.135、 - 0.135、0.271,P<0.01)。结构方程模型结果显示,社会支持水平对认知功能的总效应值为0.374,其中社会支持对认知功能的直接效应值0.353(95%CI:0.294~0.411),睡眠的中介效应值0.010(95%CI:0.002~0.020)及焦虑和睡眠的链式中介效应值0.011(95%CI:0.003~0.020)。结论 老年人社会支持可能直接影响认知功能,也可能通过睡眠质量的中介作用及睡眠和焦虑的链式中介作用间接影响认知功能。  相似文献   
6.
Human auditory ossicles, the malleus, the incus, and the stapes, are located in the tympanic cavity in the temporal bone and through forming a chain for the sound transmission from the tympanic membrane to the cochlea, they play an important role in the hearing process. Despite their clinical, phylogenetic, and evolutionary significance, the morphometry of the human ear bones has not been examined systematically. The ear ossicles are the smallest bones of the human skeleton, attaining their final size and morphology already at birth. Initially, they have been found to exhibit minimal morphometric variation, but further studies brought the opposite results. The aim of this study was to examine the morphometric variation of human auditory ossicles recovered from medieval and postmedieval subadult skeletons from Poland, Central Europe. The analysis involved in a total of 166 ear bones. Their measurements were performed on microscopic images using CorelDraw x4, according to a protocol of Quam and Rak with modification of Flohr et al. and Wadhwa et al. Our study showed a significant metric variation in the measurements taken at areas of the greatest morphological variability of the ossicles. We found that greater linear dimensions were associated with lower values of angular measurements. These results reveal the inherent variation found in these supposed functionally constrained structures. Representation of even greater number of populations, time periods, and developmental stages are needed. Further study will expand our understanding of the global scope of variation found in ear ossicular morphology and its functional implications for paleoanthropology.  相似文献   
7.
Acute diarrhea is a condition of increased water stool content, stool volume, and number of bowel movements that lasts less than 14 days. Mild diarrhea is usually self-limiting; however, undertreated moderate to severe diarrhea may cause severe dehydration and lead to hypovolemic shock. In order to prevent severe dehydration and treat patients appropriately, it is crucial for health care providers to determine the right diagnosis of patients with acute diarrhea. This article focuses on pathophysiology, general patient presentation, diagnostic tests and differential diagnosis lists of acute diarrhea to discuss which diagnosis should be made based on patient presentation and objective data.  相似文献   
8.
PurposeTo report the 5-year results from the Pivotal Multicenter Trial of Ultrasound-Guided Percutaneous Arteriovenous Fistula (pAVF) Creation for Hemodialysis Access.Materials and MethodsThe retrospective review of 107 intent-to-treat (ITT) patients from the pivotal trial provided a long-term follow-up population (LTP) of 85 patients with a median follow-up duration of 50 months (range, 12–60 months). Data evaluated in the LTP group were fistula maturation and usage, secondary procedures, and complications. The Kaplan-Meier analysis of primary patency, assisted primary patency, cumulative patency, and functional patency (time from 2-needle cannulation to abandonment) were performed for the ITT population.ResultsIn the LTP, 99% (84 of 85) of fistulae were mature, with 99% (78 of 79) of patients requiring hemodialysis using their pAVF. Sustained fistula use (2-needle cannulation at the prescribed rate, 2 of 3 sessions) was achieved in 92% (78 of 85) of patients, with 7 patients not using their pAVF because they were not on dialysis (n = 4), were on peritoneal dialysis (n = 2), and refused to use fistula (n = 1). Fistula maintenance was required in 31.8% (27 of 85) of patients and included fistula dysfunction (21.2%), thrombosis (5.9%), cannulation injury (12.9%), and arm swelling (4.7%). The number of procedures performed per patient per year to maintain function and patency was 0.32 (91 of 288) for years 2–5. The cumulative patency rates were 89.5%, 88.4%, 88.4%, 85.6%, and 82.0% for years 1, 2, 3, 4, and 5, respectively. The functional patency was 91.8% at the end of the study. There were no major complications related to pAVF during the long-term follow-up.ConclusionsPercutaneous fistulae have provided clinically effective and durable access for hemodialysis with low complications. The continued use and evaluation of pAVF are warranted.  相似文献   
9.
目的 分析我国中老年人群抑郁症状,探讨健康相关行为与抑郁间的关联性,为改善中老年抑郁干预措施及政策制定提供依据。方法 采用2018年中国健康与养老追踪调查数据,运用关联规则Apriori算法分析健康相关行为与抑郁症状间的关联,并依据支持度、置信度、提升度评价健康行为对抑郁症状的影响。结果 在8 681名调查对象中,抑郁症状的发生率为40.3%;健康相关行为与抑郁症状的关联规则中的强关联规则为无体力活动、睡眠不足、不饮酒的人更易产生抑郁症状;男性中为无体力活动、吸烟、无社交活动的人更易产生抑郁症状;女性中无体力活动、无社交活动、睡眠不足的人更易产生抑郁症状。结论 健康相关行为与抑郁是相互关联的,可通过针对多种行为的联合干预,改善中老年人的抑郁症状。  相似文献   
10.
Objective To explore associations between lipoprotein-associated phospholipase A2(Lp-PLA2) and the risk of cardiovascular events in a Chinese population, with a long-term follow-up.Methods A random sample of 2,031 participants(73.6% males, mean age = 60.4 years) was derived from the Asymptomatic Polyvascular Abnormalities Community study(APAC) from 2010 to 2011. Serum Lp-PLA2 levels were determined by enzyme-linked immunosorbent assay(ELISA). The composite endpoint was a combination of first-eve...  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