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   8003篇
  免费   496篇
  国内免费   40篇
耳鼻咽喉   113篇
儿科学   206篇
妇产科学   131篇
基础医学   1105篇
口腔科学   790篇
临床医学   676篇
内科学   1619篇
皮肤病学   228篇
神经病学   580篇
特种医学   236篇
外科学   903篇
综合类   62篇
一般理论   3篇
预防医学   833篇
眼科学   140篇
药学   598篇
中国医学   77篇
肿瘤学   239篇
  2023年   90篇
  2022年   160篇
  2021年   313篇
  2020年   182篇
  2019年   251篇
  2018年   316篇
  2017年   215篇
  2016年   253篇
  2015年   282篇
  2014年   360篇
  2013年   421篇
  2012年   655篇
  2011年   674篇
  2010年   350篇
  2009年   311篇
  2008年   503篇
  2007年   465篇
  2006年   404篇
  2005年   347篇
  2004年   274篇
  2003年   246篇
  2002年   220篇
  2001年   138篇
  2000年   126篇
  1999年   143篇
  1998年   66篇
  1997年   45篇
  1996年   41篇
  1995年   36篇
  1994年   34篇
  1993年   38篇
  1992年   45篇
  1991年   49篇
  1990年   33篇
  1989年   41篇
  1988年   48篇
  1987年   28篇
  1986年   28篇
  1985年   24篇
  1984年   26篇
  1983年   17篇
  1982年   15篇
  1981年   14篇
  1980年   27篇
  1979年   16篇
  1977年   13篇
  1976年   15篇
  1974年   17篇
  1973年   14篇
  1970年   14篇
排序方式: 共有8539条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.

Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.

Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.

Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality.  相似文献   
6.
Purpose:This study assessed the regeneration potential of mesenchymal stem cells (MSC) from adipose tissue associated with platelet-rich plasma (PRP) in bone regeneration.Methods:Thirty Wistar rats (Rattus norvegicus albinos) were divided into five groups (according to the grafting material and time to euthanasia): (1) autograft - 14 days (control), (2) autograft - 28 days (control), (3) MSC + PRP - 14 days, (4) MSC + PRP + papaverine - 14 days and (5) MSC + PRP + papaverine - 28 days. After euthanasia, the graft was removed and histological slides were prepared. They were assessed by a blinded pathologist using a previously published histological scale as parameter.Results:There was some degree of neoformed bone trabeculae (NBT) in 93.3% of the samples, as well as osteoblastic activity (OA). The autograft groups (14 and 28 days) had higher levels in the formation of bone trabeculae. Nonparametric data were analyzed using the Wilcoxon-Mann-Whitney test and proved not to be statistically significant at p < 0.05.Conclusions:Experimental parietal bone reconstruction, combining MSC, PRP and papaverine presented regeneration in all groups with no significant difference among them.Key words: Bone Regeneration, Platelet-Rich Plasma, Tissue Engineering, Rats  相似文献   
7.

Background Drug-related problems are mostly preventable or predictable circumstances that may impact on health outcomes. Clinical pharmacy activities such as medication therapy management can identify and solve these problems, with potential to improve medication safety and effectiveness. Objective To evaluate ability of medication therapy management service to detect drug-related problems and prevent adverse drug events. This study also aimed to assess the risk factors for drugrelated problem occurrence. Setting Medical intensive care unit of a public tertiary hospital in Brazil. Methods Patients were evaluated by a clinical pharmacist, who provided medication therapy management service. Detected drug-related problems were categorized according to the Pharmaceutical Care Network Europe methodology and analyzed in multinomial regression to identify risk factors. Main outcome measure Potential risk factors for drug-related problem occurrence. Results The proposed medication therapy management service allowed detection of 170 drug-related problems that had potential to reach patients causing harm and other 50 unavoidable adverse events. Drug-related problems identified were more often associated with antibacterial use, caused by improper combinations or inadequate drug dosage. These problems required interventions that were accepted by the multidisciplinary team, resulting in more than 85% adherence and total problem solving. Main risk factors identified were previous diagnosis of kidney injury (OR?=?8.38), use of midazolam (OR?=?7.96), furosemide (OR?=?5.87) and vancomycin (OR?=?4.82). Conclusion Medication therapy management proved to be an effective method not only for drug-related problem detection, but also for adverse drug event prevention, contributing to improve patient safety.

  相似文献   
8.
The aetiology of vitiligo has not been fully elucidated, and several hypotheses have been investigated; among them, the most explored assumes an autoimmune basis for the disease. Supporting this hypothesis is the frequent co-occurrence of autoimmune diseases with vitiligo. In addition, various genetic loci associated with vitiligo harbour key immune response genes. Our general hypothesis is that autoimmunity-associated genes participate in the control of vitiligo susceptibility. To investigate this hypothesis, we tested for association between vitiligo and genes CYP27B1, REL, TNFAIP3 and IL2/IL21, all previously related to autoimmune diseases associated with vitiligo. The study was performed using two independent population samples: a family-based discovery set (211 trios) and a replication set (131 cases/119 controls). Statistically significant association with vitiligo was detected between markers of the REL and IL2 gene in the family-based sample. Both association signals were concentrated among patients displaying autoimmune comorbidity and non-segmental vitiligo. Evidence for validation was detected for IL2 marker. Our findings suggest REL and IL2 as new vitiligo susceptibility genes and reinforce the hypothesis of a shared genetic mechanism controlling vitiligo and other autoimmune diseases.  相似文献   
9.
We report on 3 patients with pseudoathetosis, which are involuntary, slow, writhing movements due to loss of proprioception.  相似文献   
10.
OBJECTIVE: Nocturnal enuresis is a common pediatric problem, the etiology of which is unclear. In recent years, various studies have been published stating that children with nocturnal enuresis exhibit growth and skeletal maturation retardation. METHODS: In this cross-sectional study, we included 27 patients (16 boys, 11 girls) between the ages of 6 and 14 years who had presented with primary nocturnal enuresis (PNE) complaints. We included in the evaluation 19 healthy subjects (12 boys, 7 girls), who were the siblings of the children with PNE, as the control group. RESULTS: The patients in both groups were similar in chronological age, bone age, height and weight, with no significant difference between groups (P>0.05). CONCLUSION: The two groups in our study consisted of the same genetic background. Thus, our results were found to be different from the previous studies. We have concluded that there is no direct relationship between enuresis nocturnal and skeletal maturation.  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