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   27116篇
  免费   2849篇
  国内免费   420篇
耳鼻咽喉   262篇
儿科学   739篇
妇产科学   362篇
基础医学   1475篇
口腔科学   924篇
临床医学   5358篇
内科学   3408篇
皮肤病学   292篇
神经病学   2219篇
特种医学   643篇
外科学   2681篇
综合类   1931篇
现状与发展   1篇
一般理论   7篇
预防医学   5719篇
眼科学   197篇
药学   2617篇
  84篇
中国医学   469篇
肿瘤学   997篇
  2024年   47篇
  2023年   686篇
  2022年   895篇
  2021年   1593篇
  2020年   1560篇
  2019年   1532篇
  2018年   1461篇
  2017年   1367篇
  2016年   1282篇
  2015年   1147篇
  2014年   2044篇
  2013年   2764篇
  2012年   1429篇
  2011年   1602篇
  2010年   1170篇
  2009年   1174篇
  2008年   1167篇
  2007年   1121篇
  2006年   886篇
  2005年   832篇
  2004年   678篇
  2003年   580篇
  2002年   476篇
  2001年   453篇
  2000年   361篇
  1999年   302篇
  1998年   247篇
  1997年   221篇
  1996年   214篇
  1995年   168篇
  1994年   166篇
  1993年   119篇
  1992年   110篇
  1991年   86篇
  1990年   68篇
  1989年   62篇
  1988年   39篇
  1987年   46篇
  1986年   40篇
  1985年   47篇
  1984年   36篇
  1983年   18篇
  1982年   23篇
  1981年   18篇
  1980年   13篇
  1979年   10篇
  1978年   4篇
  1976年   3篇
  1975年   7篇
  1974年   4篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Introduction People with intellectual disabilities are now acknowledged to be susceptible to the full range of mental health disorders. This acknowledgement has resulted in the need to develop and evaluate instruments for the assessment and detection of mental health problems. This research evaluates the use of the Brief Symptom Inventory (BSI) with 200 people with mild intellectual disabilities representing community, clinical and forensic populations. Results and conclusions Results illustrate the reliability of the BSI for each of the groups and demonstrates how the Positive Symptom Total (PST) index effectively discriminates between study groups. Case rates for each group are provided. The study illustrates that the BSI could be employed as a brief multitrait assessment instrument and as a treatment outcome measure with people with an intellectual disability.  相似文献   
72.
BACKGROUND: Measurement of muscle mass is useful for evaluating protein nutritional status. Various methods for estimating muscle mass in haemodialysis patients have recently been developed. METHODS: The validity of the estimate of creatinine production calculated with the creatinine kinetic model (CKM) was examined in 46 haemodialysis patients by comparing it with the actual creatinine production, this being determined from the sum of creatinine appearing in the dialysate and the estimated metabolic degradation. The correlation of various other muscle mass indices with creatinine production was also investigated in these patients. RESULTS: The estimate of creatinine production using CKM was significantly correlated with creatinine production calculated from the spent dialysate plus an estimate for the extra-renal creatinine degradation (r=0.90, P<0.001). A Bland-Altman analysis revealed that the mean prediction error for the estimate of creatinine production by CKM was +0.10 g/day and the limits of agreement were +0.34 to -0.14 g/day. The cross-sectional area of the thigh muscle measured by computed tomography (CT) was also significantly correlated with creatinine production (r=-0.86, P<0.01). In contrast, the correlations of 3-methylhistidine production measured in the spent dialysate, the mid-upper arm muscle circumference and the skeletal muscle mass estimated by an anthropometric prediction model with creatinine production were lower (r<0.82). CONCLUSION: Creatinine production calculated using CKM and CT measurement of thigh muscle area are valid methods for estimating muscle mass during routine clinical examinations of haemodialysis patients.  相似文献   
73.
目的 评价核酸或核苷酸用于临床营养支持和免疫调节治疗的安全性、有效性和经济学价值。方法 检索中国生物医学文献数据库、Cochrane图书馆、MEDLINE光盘数据库、EMBASE光盘数据库,并联机检索SCI数据库,鉴定有关随机对照试验(RCTs),采用RevMan4.l进行Meta-分析。结果 纳入46个随机对照试验,涉及核酸/核苷酸用于肠内营养支持、婴儿营养、免疫调节治疗。18个研究报告了含核苷酸组分的免疫增强型肠内营养对外科术后和危重症患者预后的影响,合并分析发现免疫营养对患者感染率、住院时间和费用有肯定意义。发现1个报告在母乳代用品中加入核苷酸对婴儿免疫功能影响的研究,但报告对临床结局无明显影响。27个对“免疫核酸”用于免疫调节治疗的随机对照试验均为低质量研究,合并分析无法肯定iRNA的临床价值。结论 在外科术后患者应用免疫肠内营养制剂可降低感染率、缩短住院时间并可能减少住院费用,但不能确定作为组分之一的核苷酸的作用。尚无证据支持在母乳代用品中添加核苷酸具有临床意义。不能肯定免疫核酸是否具有免疫调节作用,亦未发现核酸在延缓衰老、改善老年人健康状况方面的可用证据。建议对核酸、核苷酸用于营养支持治疗和免疫调节治疗进行进一步研究,严格规范“核酸营养品”的宣传和应用。  相似文献   
74.
Female rats consistently show a pattern of differences in defensive behaviors compared to males which parallel the effects of exposure to a nonpainful threat stimulus (cat or cat odor) in the same tests and measures. These indications of greater defensiveness for females are particularly common in situations involving potential, as opposed to actual and present, threat, a factor which probably also reflects ceiling or floor effects in situations involving very intense defensiveness. In addition, pharmacological studies indicate sex differences in the effects of selective serotonin (5-HT) receptor agonists and antagonists on defensive responding. These findings indicate that sex effects must be considered in studies of the pharmacological control of defensive behaviors, and suggest that responsivity to sex effects may be an additional criterion for the suitability of animal models of anxiety.  相似文献   
75.
数字疼痛量表和描述疼痛量表的相关性研究和改进   总被引:14,自引:0,他引:14  
目的探讨"长海痛尺"的科学性和可行性.方法研究证明数字疼痛量表(NRS)和描述疼痛量表(VRS)的相关性,并设计"长海痛尺".结果 NRS和VRS之间相关性良好,相关系数r为0.8241.结论 "长海痛尺"的设计具有一定的科学依据,且具有简便、易理解、结果相对准确的特点,可以满足临床一线工作的需要.  相似文献   
76.
Pressure ulcers are a high-risk, high-volume, and high-cost problem for persons with disabilities. This article describes four tools published in the literature and reports the validity, reliability, strengths, and limitations of each. These tools include the Pressure Ulcer Scale for Healing (PUSH), the Pressure Sore Status Tool (PSST), the Sussman Wound Healing Tool (SWHT), and the Sessing Scale. Rehabilitation nurses should use a consistent framework with accurate quantification to assess, document, and monitor changes in pressure ulcers over time. Such a measurement tool must prove valid for the disabled population in which the tool is used. This will enable healthcare providers to communicate more effectively and evaluate the therapeutic plan of care.  相似文献   
77.
78.
Summary The retrospective assessment of symptoms and syndromes is a basic measure in research of the longitudinal course of schizophrenia. In spite of its importance there have been few studies evaluating the standard of quality of instruments for retrospective data collection. Combining retrospectively and cross-sectionally collected data on schizophrenic symptomatology in a cohort study over a period of 5 years revealed a significant underestimation of symptoms when assessed in retrospect. The need for studies on the validity of instruments for the retrospective assessment of symptoms is stressed.  相似文献   
79.
Between 23 and 70% of occupants involved in frontal impacts sustain cervical spine injuries, many with neurological involvement. It has been hypothesized that cervical spinal cord compression and injury may explain the variable neurological profile described by frontal impact victims. The goals of the present study, using a biofidelic whole cervical spine model with muscle force replication, were to quantify canal pinch diameter (CPD) narrowing during frontal impact and to evaluate the potential for cord compression. The biofidelic model and a sled apparatus were used to simulate frontal impacts at 4, 6, 8, and 10 g horizontal accelerations of the T1 vertebra. The CPD was measured in the intact specimen in the neutral posture (neutral posture CPD), under static sagittal pure moments of 1.5 Nm (pre-impact CPD), during dynamic frontal impact (dynamic impact CPD), and again under static pure moments following each impact (post-impact CPD). Frontal impact caused significant (P<0.05) dynamic CPD narrowing at C0-dens, C2-C3, and C6-C7. The narrowest dynamic CPD was observed at C0-dens during the 10 g impact and was 25.9% narrower than the corresponding neutral posture CPD. Interpretation of the present results indicate that the neurological symptomatology reported by frontal impact victims is most likely not due to cervical spinal cord compression. Cord compression due to residual spinal instability is also not likely.  相似文献   
80.
As our world becomes increasingly multicultural in nature, multilingual skills constitute an everyday phenomenon in schools. Since most of the second-language research has focused on school-age students, more research had to be conducted with language-minority students at the kindergarten level in order for psychologists and educators to develop effective and efficient systems for evaluating and tracking the developmental status of young language-minority children. The purpose of this study was to investigate the potential usefulness of a standardized continuous progress measure, the Picture Naming Individual Growth and Development Indicator, to longitudinally assess language development in 23 language-minority children, as well as in 13 native English-speaking children. Results indicated that we could use the Picture Naming Individual Growth and Development Indicator to detect differences in first-language and second-language development in language-minority children, as well as to detect differences between the two groups of children in their expressive English-language skills.  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