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   1940篇
  免费   116篇
  国内免费   23篇
耳鼻咽喉   23篇
儿科学   37篇
妇产科学   13篇
基础医学   233篇
口腔科学   43篇
临床医学   184篇
内科学   377篇
皮肤病学   8篇
神经病学   220篇
特种医学   56篇
外科学   353篇
综合类   25篇
预防医学   194篇
眼科学   23篇
药学   139篇
中国医学   2篇
肿瘤学   149篇
  2023年   23篇
  2022年   28篇
  2021年   63篇
  2020年   32篇
  2019年   61篇
  2018年   68篇
  2017年   32篇
  2016年   51篇
  2015年   42篇
  2014年   52篇
  2013年   96篇
  2012年   118篇
  2011年   144篇
  2010年   70篇
  2009年   64篇
  2008年   95篇
  2007年   101篇
  2006年   92篇
  2005年   65篇
  2004年   80篇
  2003年   64篇
  2002年   73篇
  2001年   39篇
  2000年   34篇
  1999年   32篇
  1998年   16篇
  1997年   11篇
  1996年   16篇
  1995年   9篇
  1994年   18篇
  1992年   26篇
  1991年   31篇
  1990年   19篇
  1989年   24篇
  1988年   9篇
  1987年   8篇
  1985年   14篇
  1984年   9篇
  1983年   13篇
  1982年   9篇
  1980年   9篇
  1979年   14篇
  1978年   9篇
  1975年   9篇
  1972年   12篇
  1970年   7篇
  1966年   7篇
  1933年   7篇
  1930年   8篇
  1915年   8篇
排序方式: 共有2079条查询结果,搜索用时 39 毫秒
81.

Introduction

In response to the need for simple, rapid means of quantifying surgical capacity in low resource settings, Surgeons OverSeas (SOS) developed the personnel, infrastructure, procedures, equipment and supplies (PIPES) tool. The present investigation assessed the inter-rater reliability of the PIPES tool.

Methods

As part of a government assessment of surgical services in Santa Cruz, Bolivia, the PIPES tool was translated into Spanish and applied in interviews with physicians at 31 public hospitals. An additional interview was conducted with nurses at a convenience sample of 25 of these hospitals. Physician and nurse responses were then compared to generate an estimate of reliability. For dichotomous survey items, inter-rater reliability between physicians and nurses was assessed using the Cohen’s kappa statistic and percent agreement. The Pearson correlation coefficient was used to assess agreement for continuous items.

Results

Cohen’s kappa was 0.46 for infrastructure, 0.43 for procedures, 0.26 for equipment, and 0 for supplies sections. The median correlation coefficient was 0.91 for continuous items. Correlation was 0.79 for the PIPES index, and ranged from 0.32 to 0.98 for continuous response items.

Conclusions

Reliability of the PIPES tool was moderate for the infrastructure and procedures sections, fair for the equipment section, and poor for supplies section when comparing surgeons’ responses to nurses’ responses—an extremely rigorous test of reliability. These results indicate that the PIPES tool is an effective measure of surgical capacity but that the equipment and supplies sections may need to be revised.  相似文献   
82.
83.
The use of preimplantation kidney biopsies (PIKBs) to aid deceased donor kidney utilization decisions is controversial. Outcomes of transplants that had been biopsied after the decision had been made to implant were analysed, in order to determine the association between chronic histological changes at implantation and graft outcomes. A retrospective analysis of transplants between the year range 2006–2015 was performed. Karpinski scores on biopsies were collected, and graft outcomes were analysed using univariate and multivariable techniques. Also, Karpinski scores from single and dual kidney transplants from older donors were examined to determine if knowledge of the score preoperatively would have altered utilization. Four hundred and eight single kidneys were transplanted. Although kidneys with scores >4 had lower 1‐ and 3‐year median (IQR) estimated glomerular filtration rates (eGFRs) than those scoring 0–4 (51 (37–66) vs. 35 (26–52) ml/min/1.73 m2, P < 0.001, and 52 (34–64) vs. 35 (24–52) ml/min/1.73 m2, P < 0.001, respectively), there was no significant association between Karpinski score and death‐censored graft survival on univariate or multivariable analyses. The utilization analysis (75 single and 25 dual kidney transplant recipients) suggested that systematic use of PIKBs would have resulted in 29% fewer patients being transplanted. This analysis does not support the systematic use of PIKBs to determine deceased donor kidney utilization.  相似文献   
84.
Background/purposeColectomy with ileal pouch-anal anastomosis (IPAA) is the standard of care for patients with familial adenomatous polyposis (FAP) and refractory ulcerative colitis (UC). The rates of postoperative complications are not well established in children. The objective of this systematic review is to establish benchmark data for morbidity after pediatric IPAA.MethodsPubMed, Embase, and The Cochrane Library were searched for studies of colectomy with IPAA in patients ≤ 21 years old. UC studies were limited to the anti-tumor necrosis factor-α agents era (1998–present). All postoperative complications were extracted.ResultsThirteen studies met the inclusion criteria (763 patients). Compared to patients with FAP, UC patients had a higher prevalence of pouch loss (10.6% vs. 1.5%). Other major complications such as anastomotic leak, abscess, and fistula were uncommon (mean prevalence 4.9%, 4.2%, and 5.0%, respectively, for patients with UC; 8.7%, 4.2%, and 4.3% for FAP). The most frequent complication was pouchitis (36.4% of UC patients).ConclusionsDevastating complications from colectomy and IPAA are rare, but patients with UC have poorer outcomes than those with FAP. Much of the morbidity may therefore stem from patient or disease factors. Multicenter, prospective studies are needed to identify modifiable risks in patients with UC undergoing IPAA.Level of evidencePrognostic, level II.  相似文献   
85.
Cognitive reserve is one's mental resilience or resistance to the effects of structural brain damage. Reserve effects are well established in people with multiple sclerosis (PwMS) and Alzheimer's disease, but the neural basis of this phenomenon is unclear. We aimed to investigate whether preservation of functional connectivity explains cognitive reserve. Seventy‐four PwMS and 29 HCs underwent neuropsychological assessment and 3 T MRI. Structural damage measures included gray matter (GM) atrophy and network white matter (WM) tract disruption between pairs of GM regions. Resting‐state functional connectivity was also assessed. PwMS exhibited significantly impaired cognitive processing speed (t = 2.14, p = .037) and visual/spatial memory (t = 2.72, p = .008), and had significantly greater variance in functional connectivity relative to HCs within relevant networks (p < .001, p < .001, p = .016). Higher premorbid verbal intelligence, a proxy for cognitive reserve, predicted relative preservation of functional connectivity despite accumulation of GM atrophy (standardized‐β = .301, p = .021). Furthermore, preservation of functional connectivity attenuated the impact of structural network WM tract disruption on cognition (β = ?.513, p = .001, for cognitive processing speed; β = ?.209, p = .066, for visual/spatial memory). The data suggests that preserved functional connectivity explains cognitive reserve in PwMS, helping to maintain cognitive capacity despite structural damage.  相似文献   
86.
Chronic cerebrospinal venous insufficiency (CCSVI) was recently described in multiple sclerosis patients. CCSVI is characterized by impaired brain venous drainage due to outflow obstruction in the extracranial venous system, mostly related to anomalies in the internal jugular and azygos veins. The current CCSVI diagnosis is based on Doppler sonography of extracranial and transcranial venous hemodynamics criteria. To date, prevalence estimates of CCSVI, provided by different groups using various imaging methods of assessment, vary widely from none to 100%. There is an urgent need to define and validate the spectrum of cranial/extracranial venous anomalies and to establish reliable, diagnostic gold-standard test(s). The potential usefulness of endovascular treatment for CCSVI in multiple sclerosis patients is still unknown.  相似文献   
87.
88.
As many as 66% of systemic lupus erythematosus (SLE) patients have been reported to have cognitive deficits. These deficits are often associated with information processing speed and working memory. Similarly, processing speed and working memory impairments are the hallmark of cognitive dysfunction in multiple sclerosis (MS). The Paced Auditory Serial Addition Test (PASAT) places high demands on processing speed and working memory. Fisk and Archibald, however, demonstrated that the total score of the PASAT does not accurately reflect impairments in these cognitive processes. They found that MS patients used a chunking strategy to obtain correct responses and reduce the cognitive demands of the task. In the present study, PASAT performance was examined for 45 SLE patients and 27 controls using alternative scoring procedures. Although the total number of correct responses did not differ between SLE and controls at the 2.4 or 2.0 s presentation rates, SLE patients had fewer dyads (correct consecutive responses) than controls at the faster rate, and more chunking responses than controls at both rates. Disease activity, disease duration, depression, fatigue, and corticosteroids could not account for these differences. The findings suggest that SLE patients, like MS patients, chunk responses more often than controls, and that this scoring procedure may better reflect the working memory and processing speed deficits present in SLE.  相似文献   
89.
前列痛栓治疗前列腺痛的药效学研究   总被引:1,自引:0,他引:1       下载免费PDF全文
目的:探讨和验证前列痛栓治疗前列腺痛的药效。方法:采用小鼠肛门给药,以空白,消炎痛栓为对照组。测定前列痛栓对小鼠扭体次数,网状内皮系统吞噬指数,耳廓肿胀,肉芽增生及大鼠小肠肌电的影响。结果:前列痛栓能明显减少小鼠扭体次数,优于消炎痛栓;对网状内皮系统吞噬功能,二甲苯所致小鼠耳廓肿胀和滤纸片埋入形成的肉芽增生及大鼠小肠肌电的影响。与消炎痛栓相近。结论:前列痛栓治疗前列腺痛有显著的镇痛作用。  相似文献   
90.

ABSTRACT

BACKGROUND/PURPOSE

To assess correlation between brain lesions and clinical status with 1.5T and 3T magnetic resonance imaging (MRI).

METHODS

Brain MRI fluid‐attenuated inversion‐recovery (FLAIR) sequences were performed in 32 multiple sclerosis (MS) patients. Expanded Disability Status Scale (EDSS) score (mean ± standard deviation) was 2 ± 2.0 (range 0‐8), disease duration 9.3 ± 8.0 (range .8‐29) years.

RESULTS

FLAIR lesion volume (FLLV) at 3T was higher than at 1.5T (P= .01). Correlation between 1.5T FLLV and EDSS score was poor, while 3T FLLV correlated moderately and significantly (rs= .39, P= .03). When controlling for age and depression, correlations between FLLV and cognitive measures were significant at 1.5T for the Judgment of Line Orientation test (JLO) (rs=−.44, P= .05), the Symbol Digit Modalities Test (SDMT) (rs=−.49, P= .02), and the California Verbal Learning Test Delayed Free Recall (CVLT DR) (rs=−.44, P= .04). Correlations at 3T were also significant for these tests, but of greater magnitude: JLO (rs=−.70, P= .0005), SDMT (rs=−.73, P= .0001), CVLT DR (rs=−.061, P= .003). Additional significant correlations obtained only at 3T included the 2 second‐paced auditory serial addition test (rs=−.55, P= .01), the Brief Visuospatial Memory Test‐Delayed Free Recall (rs=−.56, P= .007), and the California Verbal Learning Test Total Recall (rs=−.42, P= .05).

CONCLUSION

MRI at 3T may boost sensitivity and improve validity in MS brain lesion assessment.
  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