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   360600篇
  免费   25305篇
  国内免费   7971篇
耳鼻咽喉   4598篇
儿科学   9871篇
妇产科学   6618篇
基础医学   29174篇
口腔科学   8185篇
临床医学   39478篇
内科学   46013篇
皮肤病学   4619篇
神经病学   20365篇
特种医学   8798篇
外国民族医学   34篇
外科学   40251篇
综合类   54539篇
现状与发展   15篇
一般理论   29篇
预防医学   35691篇
眼科学   5776篇
药学   31496篇
  420篇
中国医学   33633篇
肿瘤学   14273篇
  2024年   3975篇
  2023年   6802篇
  2022年   10770篇
  2021年   14381篇
  2020年   13526篇
  2019年   19014篇
  2018年   16458篇
  2017年   13425篇
  2016年   11034篇
  2015年   10292篇
  2014年   20862篇
  2013年   22280篇
  2012年   19084篇
  2011年   20588篇
  2010年   16546篇
  2009年   15266篇
  2008年   14783篇
  2007年   15267篇
  2006年   13351篇
  2005年   11632篇
  2004年   9494篇
  2003年   8352篇
  2002年   6572篇
  2001年   5875篇
  2000年   4857篇
  1999年   4185篇
  1998年   3455篇
  1997年   3294篇
  1996年   2881篇
  1995年   2750篇
  1994年   2655篇
  1993年   2103篇
  1992年   2109篇
  1991年   1835篇
  1990年   1650篇
  1989年   1449篇
  1988年   1394篇
  1985年   3849篇
  1984年   4846篇
  1983年   3361篇
  1982年   3843篇
  1981年   3585篇
  1980年   3185篇
  1979年   2935篇
  1978年   2560篇
  1977年   1926篇
  1976年   2166篇
  1975年   1639篇
  1974年   1436篇
  1973年   1280篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Nephrolithiasis is a common pathology encountered in the primary care and emergency department (ED) setting. In 2009 alone, there were over one million ED visits related to nephrolithiasis Higa et al. (2017) [1]. Emergent treatment options range from non-invasive pain control and patient education to lithotripsy and other invasive urologic procedures depending on stone location and related pathology. Urethral calculi are estimated to represent 0.3% of all urinary stone diseases Verit et al. (2006) [2]. There are very few case reports documenting distal urethral stone removal in the ED. Here we present a case of distal urethral stone impaction and the removal of this stone by ED providers, leading to expedited care and prevention of consultation and possible admission.  相似文献   
32.
Introduction: Significance testing for comparison of the baseline differences between the intervention arms has received a strong condemnation. The goal of this study was to assess the prevalence of randomized controlled trials (RCTs) comparing the baseline characteristics between intervention groups using significance tests in top ten impact factor dental journals.

Materials and methods: RCTs published in 10 high impact factor dental journals were searched in PubMed database. Literature search was limited to time duration of 5 years from September 2012 to August 2017.

Results: We analysed 521 RCTs after excluding 47 non-RCT articles from the total of 568 articles. Baseline demographic characteristics table was not reported in 45.9% of the RCTs and 26.2% of the RCTs did not report table of baseline clinical characteristics. In 38.9% of the studies, significance testing was employed to compare baseline differences between the intervention arms.

Conclusions: Many trials published in the reputed dental journals failed to follow the recommendations of CONSORT statement regarding reporting of baseline tables and avoiding comparison of baseline differences with significance test.  相似文献   
33.
34.
35.
36.
37.

Context

Quality of life (QoL) is increasingly recognized as an important outcome of cancer treatment. Previous studies have examined clinical predictors of QoL, but with the increasing prevalence of wearable sensors that monitor sleep and activity patterns, further investigation into whether these behaviors are predictive of post-treatment QoL is now feasible. Among patients receiving aggressive cancer treatment such as hematopoietic cell transplantation (HCT), analysis of circadian rhythms (24-hour patterns of sleep and activity) via wearable sensors is limited.

Objective

To evaluate the relationship between overall QoL and circadian rhythms in patients receiving allogeneic HCT.

Methods

Patients wore an ActiGraph GT3X (Pensacola, FL) activity monitor for at least 72 hours before the initiation of conditioning chemotherapy and transplantation and completed a QoL (Functional Assessment of Cancer Therapy-General [FACT-G]) assessment. QoL assessments were also completed 1, 3, and 6 months after HCT.

Results

Patients (n = 45, M age = 55) were mostly male (66%) with a total FACT-G score of 80.96 (SD = 16.05) before HCT. Mixed models revealed robust cross-sectional associations between overall QoL and multiple circadian rhythmicity parameters, including durations of high physical activity, overall circadian rhythmicity, and earlier starts of daily activity (P's < .01). Recovery of QoL after transplant was predicted by longer pre-transplant durations of high physical activity (P = .04) and earlier evening retirement (P = .04).

Conclusion

Our findings suggest that wearable sensor information is a promising method of predicting recovery of QoL after HCT. Additional studies are needed to confirm these findings in a larger sample.  相似文献   
38.

Background and purpose

The vein of Galen aneurysmal malformation (VGAM) is a rare congenital vascular malformation with a higher morbidity and mortality, especially in neonates. Ultrasound, CT and MR are usually used in diagnosis and treatment monitoring of these disorders. In this current study, we aim to examine utility of SWI in evaluation of treatment response in infants with VGAM.

Materials and methods

We performed a retrospective chart analysis of children with VGAM in our institution between January 2008 and December 2016. Inclusion criteria included; confirmed VGAM on DSA; available SWI sequence at baseline and at follow up after at least a single embolization session; age at initial MR of 18?years or younger. Signal intensity and Angioarchitecture of VGAM and cerebral veins on SWI, as well as hydrocephalus and clinical outcome were evaluated.

Results

Of 11 patients identified with VGAM in our institution, 5 children (3 males and 2 females) satisfied the inclusion criteria. The average age at initial MR was 29?days (range 1–120). Fourteen MRI were available for review. All children had VGAM of mural type. Intramedullary veins were dilated and SWI-hypointense in all children, while subependymal and sulcal veins were dilated and SWI-hypointense in 4 patients on initial MRI. On the first available follow up MRI, cerebral veins have mostly normalized in 4 children and remained mostly dilated and SWI-hypointense in 1 child; even after complete treatment of the VGAM.

Conclusion

Our preliminary findings show that SWI seems to offer a beneficial non-invasive tool in evaluating passive venous congestion patterns in pediatric patients with VGAM. It remains to be determined in larger studies, the clinical significance of these SWI changes.  相似文献   
39.

Background

Vitiligo is an autoimmune disease with varying pathological features. Activation of the CCL20-CCR6 axis plays an important role in chronic inflammatory diseases. However, whether CCL20-CCR6 and Th1/17 cells are indicative of active vitiligo is unclear.

Objective

To investigate the potential role of CCL20 and the involvement of Th1/17 and Tc1/17 cells in the mechanism in vitiligo.

Methods

One hundred patients with vitiligo, and 20 healthy controls were included. The serum and blister fluid IL-17, IFN-γ, CCL20, and CXCL10 were studied using enzyme-linked immunosorbent assays. The numbers of Th1/17 cells and Tc1/17 cells in circulation were quantified using flow cytometry. CCR6 mRNA in peripheral blood mononuclear cells (PBMCs) was analyzed by real-time polymerase chain reaction and the protein level was confirmed by western blotting. CCR6 and CCL20 expression in lesions was analyzed by immunohistochemistry.

Results

The serum CCL20 level was significantly elevated in patients with vitiligo. The level of serum CCL20 was higher in active than in the stable stage, which correlated positively with the Vitiligo European Task Force spreading score and the Vitiligo Area Scoring Index score. Patients with active vitiligo had elevated numbers of circulating Th1/17 cells and Tc1/17 cells, and upregulated expression of CCR6 in PBMCs and lesions. After effective treatment, the level of CCL20 in sera and blister fluid was significantly decreased, as were the numbers of circulating Th1/17 cells and Tc1/17 cells.

Conclusion

CCL20 might be a vital biomarker of active vitiligo, and circulating Th1/17 and Tc1/17 cells are involved in the pathogenesis of vitiligo.  相似文献   
40.
Objectives: Previous research has shown a decline in Theory of mind (ToM) associated with normal aging. However, very few studies have investigated older people’s ToM using an ecological approach. The present study was designed to fill this gap and examine older people’s frequency of mental state talk (MST) in describing their best friend, together with their performance on a traditional ToM task. In addition, the study examined the association between these two ToM indices and relationships with friends and family members.

Method: Seventy-two healthy older adults (age range 60–79) participated in the study. We measured ToM ability with a classic measure, the Faux Pas task, and selected the Describe-a-friend task to measure MST frequency; social relationships were investigated with the Lubben Social Network Scale. Correlation and regression analyses were performed.

Results: No significant association between MST and scores on the Faux Pas task emerged. In addition, MST (but not Faux Pas scores) significantly predicted friendships (but not family relationships) over and above general cognitive functioning.

Conclusion: These findings show the crucial distinction between possessing an ability and using it in daily life and suggest the need to move toward more ecological measures of older adults’ abilities. In addition, the present results indicate that the spontaneous use of ToM ability, not the ability per se, impacts on older adults’ social relationships.  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