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   1747篇
  免费   131篇
  国内免费   4篇
耳鼻咽喉   10篇
儿科学   65篇
妇产科学   56篇
基础医学   195篇
口腔科学   20篇
临床医学   345篇
内科学   289篇
皮肤病学   23篇
神经病学   169篇
特种医学   31篇
外科学   159篇
综合类   16篇
一般理论   5篇
预防医学   249篇
眼科学   12篇
药学   112篇
中国医学   5篇
肿瘤学   121篇
  2023年   16篇
  2022年   10篇
  2021年   34篇
  2020年   31篇
  2019年   49篇
  2018年   53篇
  2017年   47篇
  2016年   48篇
  2015年   39篇
  2014年   76篇
  2013年   115篇
  2012年   115篇
  2011年   136篇
  2010年   84篇
  2009年   73篇
  2008年   110篇
  2007年   124篇
  2006年   105篇
  2005年   111篇
  2004年   96篇
  2003年   74篇
  2002年   85篇
  2001年   14篇
  2000年   10篇
  1999年   24篇
  1998年   32篇
  1997年   15篇
  1996年   8篇
  1995年   8篇
  1994年   11篇
  1993年   11篇
  1992年   9篇
  1991年   7篇
  1990年   5篇
  1989年   11篇
  1987年   8篇
  1985年   4篇
  1984年   4篇
  1983年   5篇
  1981年   4篇
  1980年   5篇
  1979年   5篇
  1978年   5篇
  1977年   5篇
  1975年   3篇
  1974年   3篇
  1972年   3篇
  1971年   6篇
  1969年   3篇
  1964年   3篇
排序方式: 共有1882条查询结果,搜索用时 211 毫秒
1.
Acute skin toxicity in adjuvant breast radiation can be reduced with modern radiotherapy (RT) techniques. However, having reviewed the literature, we found no dosimetric constraint for acute skin toxicity that would be applicable to modern RT planning. This study aimed to identify dosimetric factors that are associated with higher rates of acute skin toxicity. A retrospective review was carried out including women who received adjuvant forward-planned intensity-modulated radiotherapy (IMRT) after breast-conserving surgery. Acute skin toxicity grade was prospectively recorded. A total of 131 patients were analyzed. On multivariate analysis, the V105%?>?30?cc (p?=?0.013) and the use of conventional fractionation (CF) (p?=?0.001) were statistically significant for acute skin toxicity. On literature review, current quantitative dosimetric parameters that have shown statistical significance include a V107%?>?3?cc in hypofractionation (HF), V107%?>?9?cc in CF, treated volume 110%?>?5.13%, and V107%?>?28.6%. There is little evidence on the predictive value of clinically applicable dosimetric factors in acute skin toxicity. Given the recent improvements in RT planning, we would consider a V107% or a V110% too high a dosimetric value to be useful for the majority of patients. We have shown that a V105% of greater than 30?cc is significantly associated with acute skin toxicity, controlling for other variables. We suggest that this is currently the most useful modifiable parameter available to reduce skin toxicity and is applicable to modern RT planning. We also suggest that consideration be given to hypofractionated schedules to further reduce acute skin toxicity.  相似文献   
2.
3.

Study objectives

The primary objective of this study was to compare Emergency Department patients with first-time versus recurrent acute pancreatitis.

Methods

This study was a retrospective chart review of patients with a diagnosis of acute pancreatitis who presented to a single academic urban emergency department from 2012 to 2016. Criteria for inclusion were clinical symptoms of pancreatitis, age greater than or equal to 18?years, ED diagnosis of acute pancreatitis, and an abdominal CT scan within 24?h of triage. Exclusion criteria were traumatic mechanism and pregnancy. Charts were reviewed by a minimum of two trained abstractors using structured data collection sheets and discrepancies were resolved by a third abstractor. Patients with first time acute pancreatitis versus recurrent acute pancreatitis were compared to determine differences in characteristics, management and disposition.

Results

250 patients were included in the study. Of these, 165 patients had first-time acute pancreatitis and 85 patients had recurrent acute pancreatitis. Demographics, vital signs and initial lab values were the same in both groups. Patients with recurrent acute pancreatitis were more likely to have significant findings on CT (Modified CT Severity Index, 2.09 versus 1.43, p?<?0.05), more likely to require IV opiates (96% versus 75%, p?<?0.001) and less likely to need ICU admission (8% versus 19%, p?=?0.03).

Conclusion

ED patients with recurrent acute pancreatitis demonstrated more significant findings on CT compared to patients with first-time acute pancreatitis but were less likely to require ICU admission.  相似文献   
4.
5.
Background/objectivesTo investigate the association between optical coherence tomography (OCT) markers of lesion activity and changes in visual acuity (VA) during anti-vascular endothelial growth factor (anti-VEGF) therapy of eyes diagnosed with neovascular age-related macular degeneration (nAMD); and how VA and OCT markers are considered in physicians’ decision to retreat with anti-VEGFs.Subjects/methodsRetrospective, non-comparative, non-randomised cohort study involving electronic medical record data collected from 1190 patient eyes with nAMD diagnosis at two sites in the United Kingdom. Two sub-cohorts consisting of 321 and 301 eyes, respectively, were selected for analyses.ResultsIn 321 eyes, absence of IRF or SRF at ≥2 clinic visits resulted in a gain of five ETDRS letters from baseline, compared with two letters gained in eyes with <2 clinic visits with absence of IRF (p = 0.006) or SRF (p = 0.042). Anti-VEGF treatment was administered at 421 clinic visits, and 308 visits were without treatment. Comparing treatment visits with non-treatment visits, the maximum difference in frequency of OCT markers of lesion activity were for intraretinal fluid (IRF; 24% versus 5%) and subretinal fluid (SRF; 32% versus 5%). Pigment epithelial detachment (PED) was reported in 58% of treatment visits compared with 36% in non-treatment visits. VA loss was not a consistent trigger for retreatment as it was present in 63% of injection visits and in 49% of non-injection visits.ConclusionsRetreatment decision making is most strongly influenced by the presence of IRF and SRF and less by the presence of PED or VA loss.Subject terms: Outcomes research, Macular degeneration  相似文献   
6.
7.
There is clear experimental evidence for a causal link between alcohol misuse and violent behaviour. Treatments for alcohol misuse with offenders are therefore justified on the grounds that they may reduce violent behaviour and thus re-offending. The current paper tested whether a 10-session CBT intervention with offenders still in prison would produce improvements across three time points (pre, post and follow up) in self-reported alcohol expectancies, aggressiveness, impulsivity, and self-efficacy in managing alcohol use and violent behaviour. The programme focussed on educating participants on the relationship between alcohol use and violence, modifying unhelpful cognitions, and providing skills based training to manage potential triggers. Data from 49 offenders in prison were collected pre-intervention, post-intervention, and at three month follow up. Long term improvements (from pre- to post-intervention and follow up) were observed with respect to alcohol expectancies (in terms of sociability and liquid courage), impulsive responding to negative affect triggers, trait anger, and confidence in managing alcohol use and offending behaviour. These findings provide preliminary evidence for the efficacy of the CBT programme in reducing harmful alcohol use and associated violence. Limitations and recommendations for future evaluation of the intervention are discussed.  相似文献   
8.

Background

Multiparametric magnetic resonance imaging (mpMRI) undoubtedly affects the diagnosis and treatment of localized prostate cancer (CaP). However, clinicians need a better understanding of its accuracy and limitations in detecting individual CaP foci to optimize management.

Objective

To determine the per-lesion detection rate for CaP foci by mpMRI and identify predictors of tumor detection.

Design, setting, and participants

We carried out a retrospective analysis of a prospectively managed database correlating lesion-specific results from mpMRI co-registered with whole-mount pathology (WMP) prostatectomy specimens from June 2010 to February 2018. Participants include 588 consecutive patients with biopsy-proven CaP undergoing 3-T mpMRI before radical prostatectomy at a single tertiary institution.

Outcome measurements and statistical analysis

We measured mpMRI sensitivity in detecting individual CaP and clinically significant (any Gleason score ≥7) CaP foci and predictors of tumor detection using multivariate analysis.

Results and limitations

The final analysis included 1213 pathologically confirmed tumor foci in 588 patients with primarily intermediate- (75%) or high-risk (12%) CaP. mpMRI detected 45% of all lesions (95% confidence interval [CI] 42–47%), including 65% of clinically significant lesions (95% CI 61–69%) and nearly 80% of high-grade tumors. Some 74% and 31% of missed solitary and multifocal tumors, respectively, were clinically significant. The majority of missed lesions were small (61.1% ≤1 cm); 28.3% were between 1 and 2 cm, and 10.4% were >2 cm. mpMRI missed at least one clinically significant focus in 34% of patients overall, and in 45% of men with multifocal lesions. On multivariate analysis, smaller, low-grade, multifocal, nonindex tumors with lower prostate-specific antigen density were more likely to be missed. Limitations include selection bias in a prostatectomy cohort, lack of specificity data, an imperfect co-registration process, and uncertain clinical significance for undetected lesions.

Conclusions

mpMRI detects less than half of all and less than two-thirds of clinically significant CaP foci. The moderate per-lesion sensitivity and significant proportion of men with undetected tumor foci demonstrate the current limitations of mpMRI.

Patient summary

Magnetic resonance imaging of the prostate before surgical removal for prostate cancer finds less than half of all individual prostate cancer tumors. Large, solitary, aggressive tumors are more likely to be visualized on imaging.  相似文献   
9.
Over 36 million people worldwide are infected with HIV. Antiretroviral therapy (ART) has proven to be highly effective to prevent HIV-1 transmission, clinical progression and death. Despite this success, the number of HIV-1 infected individuals continues increasing and ART should be taken for life. Therefore, there are two main priorities: the development of preventive vaccines to protect from HIV acquisition and achieve an efficient control of HIV infection in the absence of ART (functional cure). In this sense, in the last few years, there has been a broad interest in new and innovative approaches such as mRNA-based vaccines. RNA-based immunogens represent a promising alternative to conventional vaccines because of their high potency, capacity for rapid development and potential for low-cost manufacture and safe administration. Some mRNA-based vaccines platforms against infectious diseases have demonstrated encouraging results in animal models and humans. However, their application is still limited because the instability and inefficient in vivo delivery of mRNA. Immunogens, design, immunogenicity, chemical modifications on the molecule or the vaccine delivery methods are all crucial interventions for improvement. In this review we, will present the current knowledge and challenges in this research field. mRNA vaccines hold great promises as part of a combined strategy, for achieving HIV functional cure.  相似文献   
10.
ABSTRACT

Bachelor of Nursing students (BN) placed in long-term care encounter residents who exhibit challenging behaviors. Students are often inadequately prepared to manage these behaviors, and this is a source of distress for students. This study explored whether enhancing and restructuring theoretical and clinical courses resulted in student nurses feeling better prepared to manage residents’ challenging behaviors and improve their levels of distress. This study was conducted in two phases with 116 BN students (first phase) and 99 students (second phase) where the course on older adults was restructured. The findings of this study indicated that students who felt less prepared experienced greater distress by residents’ behaviors than those who felt better prepared. Scheduling a theoretical course on the care of older adults prior to the clinical course placement, as well as offering an online learning module focused on responsive behaviors, significantly increased students’ feelings of preparedness to manage residents’ complex behaviors.  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