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   2635篇
  免费   169篇
  国内免费   36篇
耳鼻咽喉   20篇
儿科学   50篇
妇产科学   20篇
基础医学   512篇
口腔科学   21篇
临床医学   506篇
内科学   155篇
皮肤病学   24篇
神经病学   360篇
特种医学   61篇
外科学   147篇
综合类   332篇
预防医学   458篇
眼科学   2篇
药学   103篇
  1篇
中国医学   20篇
肿瘤学   48篇
  2024年   3篇
  2023年   47篇
  2022年   133篇
  2021年   111篇
  2020年   101篇
  2019年   113篇
  2018年   88篇
  2017年   83篇
  2016年   114篇
  2015年   81篇
  2014年   171篇
  2013年   238篇
  2012年   159篇
  2011年   204篇
  2010年   133篇
  2009年   124篇
  2008年   178篇
  2007年   155篇
  2006年   120篇
  2005年   79篇
  2004年   77篇
  2003年   55篇
  2002年   41篇
  2001年   40篇
  2000年   42篇
  1999年   39篇
  1998年   24篇
  1997年   13篇
  1996年   5篇
  1995年   14篇
  1994年   9篇
  1993年   10篇
  1992年   6篇
  1991年   6篇
  1990年   1篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   3篇
  1983年   4篇
  1980年   1篇
  1977年   1篇
  1976年   3篇
  1975年   1篇
  1974年   3篇
排序方式: 共有2840条查询结果,搜索用时 0 毫秒
51.
Objective:

To establish the diagnostic validity of panoramic X-rays (PRx) in temporomandibular osteoarthrosis (OA) using the clinical and imaging criteria (magnetic resonance imaging, MRI) of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) as gold standards.

Methods:

Eighty-four patients with full clinical records (RDC/TMD), PRx, and MRI scans were selected. Two stomatologists evaluated the PRx for OA. The MRI findings were derived from the radiologist report. Intra/inter-examiner concordance was established. The diagnostic concordance between clinical signs and MRI was determined. Both were used as gold standards to calculate the validity of PRx in OA.

Results:

The diagnostic validity of PRx with MRI as gold standard was sensitivity?=?69·0% and specificity?=?67·9%. The diagnostic validity of PRx with clinical criteria as gold standard was sensitivity?=?61·6% and specificity =?57·9%.

Discussion:

Panoramic X-rays have scant diagnostic validity in temporomandibular osteoarthrosis when taking MRI or clinical criteria of RDC/TMD as gold standards.  相似文献   
52.
Although a large body of research has demonstrated the predictive power of subjective ageing for several decisive developmental outcomes, there remains some controversy about whether subjective ageing truly represents a unique construct. Thus, information about the convergent and discriminant validity of different approaches to measuring subjective ageing is still critically needed. Using data from the 2014 wave of the German Ageing Survey, we examined how three established subjective ageing measures (subjective age, global attitude toward own ageing, multidimensional ageing-related cognitions) were inter-related as well as distinct from general dispositions (optimism, self-efficacy) and well-being (negative affect, depressive symptoms, self-rated health). Using correlational and multivariate regression analysis, we found that the three subjective ageing measures were significantly inter-related (r = |.09| to |.30|), and that each measure was distinct from general dispositions and well-being. The overlap with dispositional and well-being measures was lowest for subjective age and highest for global attitudes towards own ageing. The correlation between global attitudes towards own ageing and optimism was particularly striking. Despite the high convergent validity of the different dimensions of ageing cognitions, we nevertheless observed stronger associations between specific dimensions of ageing cognitions with negative affect and self-rated health. We conclude that researchers should be aware of the multidimensional nature of subjective ageing. Furthermore, subjective age appears to be a highly aggregated construct and future work is needed to clarify its correlates and reference points.Electronic supplementary materialThe online version of this article (10.1007/s10433-019-00529-7) contains supplementary material, which is available to authorized users.  相似文献   
53.
54.
ObjectivesThe purpose of this study was to examine the reliability and validity of the Social Support Scale in Chronic Diseases (SSCII) Scale Turkish version that was developed by Hilbert-McAllister.MethodsThis was planning a methodological study. Research group consists of 163 older persons that accepted to participate in this study and who had a chronic disease. Data were collected in 15th June–15th August 2012 period from two homes for aged in İzmir Provinence. The necessary ethical approval was obtained from the institutions and each participant for research.ResultsSSCII Scale was translated to Turkish for language validity. For content validity, it was obtained of experts view and it was corrected according to expert's suggestions. For content validity, Kendall goodness-of-fit Correlation test was performed (Kendall's Wa = 0.167, χ2 = 49.337, df = 37, p = 0.084). In reliability and validity study, first of all, total item score correlation was examined. All items were upper than 0.20 correlation limit and there were a significant relationship between total item correlation score. Scale originally has 38 items in the latest version in Turkish. For reliability of the scale, it was performed the internal consistency analysis and it was find that Cronbach's alpha coefficient as 0.89. So, the scale has an acceptable level internal consistency coefficient. For the determining of scale's time stability, it was applied to initial 32 older persons after first survey. A significant relation found between test-retest scores (p = 0.000).ConclusionSSCII Scale Turkish version is a reliable and valid scale for the Turkish community.  相似文献   
55.
朱丹  曾平  韩凤  谢红 《中国全科医学》2020,23(24):3081-3085
背景 营养筛查与评估是开展规范化营养支持的基础,WS/T 552-2017《老年人营养不良风险评估》发布前后,尚缺乏关于此标准中评估工具信效度研究的有关报告。目的 评价《老年人营养不良风险评估》在京津地区有代表性的养老机构应用的信效度。方法 2019年5-6月,采用方便抽样对北京、天津7家养老机构中入住的444名老年人进行问卷调查。采用临界比、条目-总分相关系数、探索性因子分析、Cronbach's α系数和折半信度系数评价《老年人营养不良风险评估》的信效度。结果 共发放问卷474份,回收有效问卷444份,有效回收率为93.7%。《老年人营养不良风险评估》各条目临界比为-1.992~13.272,条目-总分相关系数为-0.051~0.566;探索性因子分析共提取8个公因子,累积解释变异量为62.069%,4个条目因子载荷<0.40而未达标准;《老年人营养不良风险评估》的Cronbach's α系数为0.323,折半信度为0.531,8个公因子的Cronbach's α系数为-0.542~0.649,折半信度为-0.424~0.637。结论 《老年人营养不良风险评估》在养老机构中应用时部分条目的鉴别度和同质性不高,结构效度和内部一致性不是非常理想,在进行养老机构老年人营养状况筛查与评价时,需要对条目进一步斟酌,才能更有效地评价养老机构老年人的营养状况。  相似文献   
56.
Comparisons were made of estimates of the Wechsler Adult Intelligence Scale – Revised Full Scale IQ using the two-,three- and four-subtest linear equating procedures of Kaufman (1990) and Booker and Cyr (1986) with FSIQ estimates using prorating to obtain FSIQ scores. The advantage of prorating is that it affords greater clinical flexibility in selection of subtests. The participants were 64 neuropsychiatric patients who completed the full WAIS-R from which short form and FSIQ were calculated. Prorating yielded estimates of mean IQ and categorization of IQ comparable to IQs obtained by linear equating, though there was an increased likelihood of disparate results with extreme IQ scores. Prudent clinical judgment is recommended for situations involving unusual or extreme scaled score patterns, particularly when the number of subtests is small.  相似文献   
57.
The relationship between IQ and nine effort indicators was examined in a sample of 189 neuropsychology clinic outpatients who were not in litigation or attempting to obtain disability. Participants with the lowest IQ (50–59) failed approximately 60% of the effort tests, while patients with an IQ of 60 to 69 failed 44% of effort indicators, and individuals with borderline IQ (70 to 79) exhibited a 17% failure rate. All patients with IQ < 70 failed at least one effort test. Cutoffs for the Warrington Recognition Memory Test (Words) and Finger Tapping maintained the highest specificities in low IQ samples.  相似文献   
58.
Children with attention deficit hyperactivity disorder (ADHD) exhibit a number of cognitive deficits. The current study compared patterns of attention, learning, and memory impairment on the Test of Memory and Learning (TOMAL) between 80 children with ADHD and 80 normal comparisons who were matched for age and gender. Results demonstrated that children with ADHD performed significantly worse than matched controls on the Attention/Concentration Index and the Sequential Recall Index. ROC analysis indicated that these two indexes had good classification accuracy with AUCs of.76 and.77 respectively. There were also group differences on the other index scores except the Associative Recall Index. Factor analysis of the ADHD sample extracted five factors, including an Attention factor that significantly correlated with performance on nonverbal memory tasks. Significant correlations between the TOMAL Index scores and tests of intelligence and visuomotor integration supported the convergent and discriminant validity of the test. These results provide support for the criterion validity of the TOMAL in assessing neurocognitive deficits in children with ADHD.  相似文献   
59.
The Rey Word Recognition Test, a brief and simple to administer free-standing neurocognitive performance validity test, was examined in a large known-groups sample (122 credible patients and 134 non-credible patients). Total correctly recognized was the most sensitive score, identifying 54% of non-credible participants using a cut-off of ≤6, while maintaining specificity of approximately 90%. However, specifically rates were somewhat lower in credible individuals with <12 years of education or borderline intelligence, or who were bilingual (spoke English as a second language, or learned English concurrently with another language), indicating that cut-offs may require minor adjustment in these groups. Sensitivity rates were much higher in non-credible female versus male mild traumatic brain injury patients (mTBI; 68% versus 48% for total correct), suggesting that the Rey Word Recognition Test is particularly effective in identifying performance invalidity in female mTBI compensation seekers.  相似文献   
60.
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