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   1912篇
  免费   185篇
  国内免费   60篇
耳鼻咽喉   14篇
儿科学   34篇
妇产科学   31篇
基础医学   167篇
口腔科学   37篇
临床医学   181篇
内科学   252篇
皮肤病学   47篇
神经病学   136篇
特种医学   93篇
外科学   314篇
综合类   336篇
预防医学   141篇
眼科学   12篇
药学   177篇
  2篇
中国医学   85篇
肿瘤学   98篇
  2024年   9篇
  2023年   11篇
  2022年   42篇
  2021年   61篇
  2020年   45篇
  2019年   38篇
  2018年   47篇
  2017年   54篇
  2016年   50篇
  2015年   92篇
  2014年   82篇
  2013年   126篇
  2012年   155篇
  2011年   166篇
  2010年   120篇
  2009年   116篇
  2008年   105篇
  2007年   108篇
  2006年   95篇
  2005年   100篇
  2004年   51篇
  2003年   56篇
  2002年   52篇
  2001年   37篇
  2000年   27篇
  1999年   31篇
  1998年   28篇
  1997年   20篇
  1996年   17篇
  1995年   13篇
  1994年   13篇
  1993年   17篇
  1992年   11篇
  1991年   15篇
  1990年   10篇
  1989年   16篇
  1988年   17篇
  1987年   11篇
  1986年   14篇
  1985年   7篇
  1984年   9篇
  1983年   5篇
  1982年   6篇
  1981年   4篇
  1980年   8篇
  1979年   4篇
  1977年   5篇
  1976年   8篇
  1975年   4篇
  1971年   3篇
排序方式: 共有2157条查询结果,搜索用时 15 毫秒
91.
目的 探讨动态心电图对体表心电图P.R间期延长的诊断价值,分析P—R间期延长的临床意义和预后。方法选择2008年1月至2011年8月在昆明医学院第二附属医院住院和门诊心电图有P-R间期延长的患者90例为研究对象.监测其动态心电图。分析P.R间期的变化及阵发性心房颤动、房室结双径路传导、第二度I型房室阻滞、间歇性左右束支阻滞4类心律失常。并且根据P—R间期延长程度分为3组,对比其与上述4类心律失常的关系。结果动态心动图结果中伴发第二度I型房室阻滞2l例(23.33%)、房室结双径路传导17例(18.89%)、间歇性左右束支阻滞9例(10%)、阵发性心房颤动7例(7.78%)。在所有的患者中,P.R间期延长伴发上述4类心律失常发生率为60%。心电图结果中,P-R间期延长50例,显著延长29例,过度延长11例。动态心动图结果中。P。R间期延长32例,显著延长38例,过度延长20例。结论P—R间期延长不应均视为良性和无须干预的心律失常,相反,需要进行进一步动态心动图监测及电生理检查和追踪观察,争取早期发现病变、消除病变,为临床早期诊断、早期治疗提供辅助手段。  相似文献   
92.
Abstract Background: Metabolic syndrome reaches its highest prevalence in the elderly, and evidence suggests that metabolic syndrome could be an independent risk factor for cognitive impairment. The aims of this study were to detect whether patients with metabolic syndrome have lower cognition and to investigate whether there is a relationship with cognition and single metabolic syndrome components. Methods: We assessed fasting blood glucose (FBG), high-density lipoprotein cholesterol (HDL-C), triglycerides, high-sensitivity C-reactive protein (hsCRP), and anthropometric measurements. Metabolic syndrome was diagnosed according to National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria. The population sample was divided into two groups according to the presence of metabolic syndrome. Cognitive function was investigated through the Mini-Mental State Examination (MMSE). Results: We enrolled 159 elderly subjects (mean age, 69.8±4.8 years). Seventy had metabolic syndrome. Metabolic syndrome subjects had higher hsCRP values (P<0.0001) and lower MMSE scores (P<0.0001) than those without metabolic syndrome. MMSE scores were significantly correlated with body mass index (BMI), hsCRP, metabolic syndrome, the number of metabolic syndrome components, and each of them. However, at multivariate regression analysis, only fasting blood glucose [FBG; B=-0.046; 95% confidence interval (CI) -0.066 to -0.028; P<0.0001] and the number of metabolic syndrome components (B=-0.317; 95% CI -0.572 to -0.010; P=0.042) were found to be independent predictors of lower MMSE scores. Conclusion: We found that subjects with metabolic syndrome have lower MMSE scores than those without, even without symptomatic cognitive impairment, and that the number of metabolic abnormalities is independently associated to lower MMSE scores. We suggest that these patients should always undergo cognitive screening to prevent more severe outcomes.  相似文献   
93.
目的探讨住院患者人院时不同血糖水平与住院时间、医疗费用及疾病预后的关系。方法选取2009年11月至2011年7月期间人院的4868例患者,按入院24h内测得的血糖水平分为非高血糖组3429例、高血糖组1439例,后者包括糖尿病和应激性高血糖患者;根据患者年龄分为非老年组(年龄〈60岁)2532例和老年组(年龄≥60岁)2336例;其中278例冠心病患者再分为高血糖组120例和非高血糖组158例。各组间进行有关数据比较。结果高血糖组患者的住院天数、医疗费用和总病死率均显著高于非高血糖组(中位数住院日:15vs10d,P〈0.01;中位数医疗费用:14064.7vs8980.9元,P〈0.01;死亡率:2.92%vs0.61%,P〈0.01)。按年龄分组后,无论是非老年组还是老年组中糖尿病和应激性高血糖患者的医疗费用均明显高于非高血糖患者,住院日明显延长;应激性高血糖患者的医疗费用明显高于糖尿病患者;非老年组中应激性高血糖患者的死亡率明显高于非高血糖患者,但与糖尿病患者相比无明显差异,老年组糖尿病和应激性高血糖患者的死亡率无明显差异,但均明显高于非高血糖患者。冠心病患者中糖尿病和应激性高血糖患者与非高血糖患者的年龄无明显差异,前两组的医疗费用明显高于非高血糖组,住院日更长(分别为14,15和12d)、死亡率更高(分别为6.41%,7.14%和0.63%)。结论入院时高血糖水平预示患者有更高的医疗花费、更长的住院时间和更高的死亡率。  相似文献   
94.

Objectives

To test the association between polypharmacy and 1-year change in physical and cognitive function among nursing home (NH) residents.

Design

Longitudinal multicenter cohort study based on data from the Services and Health for Elderly in Long TERm care (SHELTER) study.

Setting

NH in Europe (n = 50) and Israel (n = 7).

Participants

3234 NH older residents.

Measurements

Participants were assessed through the interRAI long-term care facility instrument. Polypharmacy was defined as the concurrent use of 5 to 9 drugs and excessive polypharmacy as the use of ≥10 drugs. Cognitive function was assessed through the Cognitive Performance Scale (CPS). Functional status was evaluated through the Activities of Daily Living (ADL) Hierarchy scale. The change in CPS and ADL score, based on repeated assessments, was the outcome, and their association with polypharmacy was modeled via linear mixed models. The interaction between polypharmacy and time was reported [beta and 95% confidence intervals (95% CIs)].

Results

A total of 1630 (50%) residents presented with polypharmacy and 781 (24%) excessive polypharmacy. After adjusting for potential confounders, residents on polypharmacy (beta 0.10, 95% CI 0.01-0.20) and those on excessive polypharmacy (beta 0.13, 95% CI 0.01-0.24) had a significantly higher decline in CPS score compared to those using <5 drugs. No statistically (P > .05) significant change according to polypharmacy status was shown for ADL score.

Conclusions

Polypharmacy is highly prevalent among older NH residents and, over 1 year, it is associated with worsening cognitive function but not functional decline.  相似文献   
95.
OBJECTIVE: To test the psychometric properties of a newly developed measure of caregiver self-efficacy, the Caregiver Self-Efficacy Scale for Transfers (CSEST), a 14-item questionnaire that measures the perceived self-efficacy of adult caregivers of dependent children and focuses on their perceived abilities and the challenges of assisting a child with restricted transfer ability. DESIGN: Reliability and validity study using survey data. SETTING: Community-based survey study. PARTICIPANTS: Adult caregivers (eg, mother, father, grandparent) of dependent minors who require transfer assistance. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Using the Rasch measurement model, the CSEST was tested for reliability and separation, validity (hierarchical and content), and factor structure. RESULTS: The CSEST yields data with sufficient reliability (reliability indices of .96 and .94 for respondents and items, respectively) as well as sufficient separation of levels of self-efficacy (item separation index, 4.13; person separation index, 5.23). The CSEST has a stable hierarchical structure with adequate content validity (standardized chi2 fit statistics <2.0) and point biserial correlations greater than .67. Factor analysis confirmed 2 insubstantial subscales; the 14-item CSEST accounted for greater than 85% of the total variance. CONCLUSIONS: The CSEST yields reliable data and valid inferences of self-efficacy from adult caregivers of children requiring transfer assistance. The CSEST may identify areas of need and/or difficulty with transfers for parents caring for dependent children.  相似文献   
96.
室壁应力与应变的关系评价高血压病左室收缩功能   总被引:21,自引:7,他引:21  
目的 探索用室壁应力 (stress)与应变 (strain)的关系评价高血压病左室收缩功能的临床价值。方法 研究对象为 5 5例高血压病患者和 3 0例健康人。应用超声心动图计算左室射血分数 (EF)、心指数 (CI)、重量指数 (LVMI)和相对室壁厚度 (RWT) ,并联合袖带肱动脉血压值计算左心室收缩期室壁经线峰值应力 (Pσm)。根据LVMI和RWT将高血压病分为左室正常构型和左室重构两组。在数字化超声工作站中应用定量组织速度成像 (QTVI)获取左室前壁心肌 2个节段长轴应变曲线和峰值收缩应变值 (PSS)。结果 ①以EF ,CI表示的心脏收缩功能 ,在高血压病左室正常构型组值中无明显变化 ;而在高血压病左室重构组中下降 ,差异具有极显著意义 (P <0 .0 1)。②Pσm在高血压病两组中较对照组均有增高 (P <0 .0 5~ 0 .0 1) ,两组间比较差异具有极显著意义 (P <0 .0 1)。③高血压病两组左室前壁基底段 (Bas)和中段 (Mid)的 pSS值均显著下降 (P <0 .0 1) ,两组间比较差异具有极显著意义 (P <0 .0 1)。④直线相关分析结果显示高血压病两组Pσm与PSSBas和PSSMid均呈显著负相关。根据正常构型组Pσm与PSSBas直线回归方程计算 ,在相同Pσm水平 ,左室重构组PSSBas的实测值显著低于预测值及实测值与预测值的比值较正常构型组显著下降 ,差  相似文献   
97.
目的:系统评价自体骨移植与骨形成蛋白治疗成人长骨骨折不愈合相关指标,为成人长骨骨折不愈合治疗提供参考依据。方法:计算机检索PuMed、Embase、Cochrane图书馆、中国知网(CNKI)、万方数据期刊全文数据库及中国生物医学文献数据库(CBM)发表的对于自体骨移植与骨形成蛋白治疗成人长骨骨折不愈合的随机对照试验,检索时间从建库至2019年3月。由2名研究者按照纳入和排除标准独立进行筛选文献,提取资料,并采用Jadad评价量表对纳入的文献进行质量评价。采用RevMan 5.3统计学软件对两种方法的感染发生率、成功愈合率、二次手术率、住院时间及术中失血量进行Meta分析。结果:共纳入7个随机对照试验研究,共652例患者,自体骨移植组有410例,骨形成蛋白组有242例。Meta分析结果显示:自体骨移植组与骨形成蛋白组在感染发生率[RR=1.32,95%CI(0.90,1.93),P=0.16],成功愈合率[RR=0.95,95%CI(0.84,1.08),P=0.43],二次手术率[RR=1.16,95%CI(0.43,3.12),P=0.76]及住院时间[MD=0.69,95%CI(-0.38,1.75),P=0.21]方面比较差异无统计学意义。自体骨移植组术中失血量明显高于骨形成蛋白组[MD=223.00,95%CI(32.72,413.28),P=0.02]。结论:对于成人长骨骨折不愈合的治疗,骨形成蛋白可以获得和自体骨移植一样的骨折愈合率,同时可以明显减少术中失血量。骨形成蛋白可能更适合成人长骨骨折不愈合的治疗。  相似文献   
98.
We describe a case of 64-year-old female patient with ventricular tachycardia intractable to medical treatment and acute heart failure following myocardial infarction. Emergency surgical ventricular reconstruction and subendocardial resection was undertaken. We discuss the option of surgical intervention in this difficult and unusual clinical scenario.  相似文献   
99.
We conducted a microarray study to identify genes that are differentially regulated in the spinal cords of mice with the inflammatory disease experimental autoimmune encephalomyelitis (EAE) relative to healthy mice. In total 181 genes with at least a two‐fold increase in expression were identified, and most of these genes were associated with immune function. Unexpectedly, ceruloplasmin (Cp), a ferroxidase that converts toxic ferrous iron to its nontoxic ferric form and also promotes the efflux of iron from astrocytes in the CNS, was shown to be highly upregulated (13.2‐fold increase) in EAE spinal cord. Expression of Cp protein is known to be increased in several neurological conditions, but the role of Cp regulation in CNS autoimmune disease is not known. To investigate this, we induced EAE in Cp gene knockout, heterozygous, and wild‐type mice. Cp knockout mice were found to have slower disease evolution than wild‐type mice (EAE days 13–17; P = 0.05). Interestingly, Cp knockout mice also exhibited a significant increase in the number of astrocytes with reactive morphology in early EAE compared with wild‐type mice at the same stage of disease. CNS iron levels were not increased with EAE in these mice. Based on these observations, we propose that an increase in Cp expression could contribute to tissue damage in early EAE. In addition, endogenous CP either directly or indirectly inhibits astrocyte reactivity during early disease, which could also worsen early disease evolution. © 2014 Wiley Periodicals, Inc.  相似文献   
100.
高效液相色谱法测定多维元素片中泛酸的含量   总被引:2,自引:0,他引:2  
目的建立复合多维元素片中泛酸的含量测定方法。方法高效液相色谱法,C18色谱柱(250mm×4.6mm,5μm);流动相:乙腈-1mL·L-1磷酸水溶液(5∶95);流速:1.0mL·min-1;柱温:25℃;检测波长:200nm。结果泛酸质量浓度在1.32132.32μg·mL-1范围内具有良好的线性关系,相关系数r=0.999 9,平均回收率为99.3%,RSD为1.4%(n=12)。结论该方法快速简便,结果准确,适用于多维元素片中泛酸含量测定。  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