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   671篇
  免费   151篇
  国内免费   7篇
耳鼻咽喉   5篇
儿科学   24篇
妇产科学   9篇
基础医学   81篇
口腔科学   10篇
临床医学   76篇
内科学   84篇
神经病学   102篇
特种医学   105篇
外科学   128篇
综合类   27篇
预防医学   98篇
眼科学   8篇
药学   37篇
中国医学   4篇
肿瘤学   31篇
  2024年   7篇
  2023年   44篇
  2022年   73篇
  2021年   79篇
  2020年   71篇
  2019年   75篇
  2018年   55篇
  2017年   46篇
  2016年   36篇
  2015年   33篇
  2014年   54篇
  2013年   48篇
  2012年   24篇
  2011年   21篇
  2010年   15篇
  2009年   21篇
  2008年   18篇
  2007年   17篇
  2006年   15篇
  2005年   6篇
  2004年   13篇
  2003年   6篇
  2002年   6篇
  2001年   7篇
  2000年   3篇
  1999年   5篇
  1998年   5篇
  1997年   3篇
  1995年   3篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1990年   2篇
  1989年   2篇
  1988年   4篇
  1986年   1篇
  1983年   1篇
  1982年   1篇
  1981年   3篇
  1978年   1篇
  1976年   1篇
排序方式: 共有829条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
输尿管镜气压弹道碎石治疗输尿管结石(附108例报告)   总被引:2,自引:0,他引:2  
目的探讨输尿管镜气压道弹碎石术治疗输尿管结石的临床疗效.方法在输尿管镜窥视下采用气压弹道碎石机对108例输尿管结石进行治疗.结果 103例原位碎石成功,总成功率95.3%,其中输尿管上段结石成功率为83.3%,中段结石为96.3%,下段结石为98.4%.平均碎石时间(4.5±2.2)min,术后1~3个月结石排净率100%.结论输尿管镜气压弹道碎石术治疗输尿管结石具有安全、有效、容易操作等特点,是治疗输尿管结石的首选方法.  相似文献   
5.
Summary Three methods for analyzing the spatial organization of visual evoked potentials were compared. Pattern reversal visual evoked potentials were obtained from a single subject under three viewing conditions: stimulation of the left, right, and both visual fields. The scalp distribution of the VEP to 1 deg checks was displayed using three recording and analysis techniques: a conventional horizontal occipital array of electrodes, topographic mapping, and 3-dimensional evoked potentials. All three techniques revealed "paradoxical" lateralization of P100. The relative merits of each technique are discussed.We are grateful to Susan Hoffmann-Nader and Rebecca Clark-Bash for data collection. This research was supported in part by the Brain Research Foundation of the University of Chicago.  相似文献   
6.
目的:利用Unigraphics(UG)三维重建技术寻找枢椎侧弓螺钉安全钉道的经过,并进行相关参数的测量.方法:对4例干燥和8例新鲜枢椎行CT扫描, UG软件重建虚拟实体,利用3.5 mm虚拟螺钉模拟进钉,寻找安全钉道经过的特征标记点.以此为基础,测定57例干燥枢椎安全钉道的内倾角与上倾角(AutoCAD环境)及进针点距峡部及下关节突外缘的距离(手工测量).结果:模拟发现横断面安全钉道经过前弓中宽后界的内中1/3交界与中宽前界的外中1/3交界,矢状面经过前弓中宽后界中部及前界中宽与上关节突下界交界处.对另57例干燥标本进行测量发现安全钉道的内倾角为左/右=(10.94±6.53)°/(11.95±2.82)°,上倾角为(13.31±5.44)°/(14.45±3.80)°,在大多数标本椎板后下方有一突起的骨嵴 (左/右=84.2%/84.98%) ,进针点多位于这一骨嵴线上(左/右=87.5%/84.9%).进针点距离下关节外侧缘左/右=(6.71±1.33)mm/(6.28±1.48)mm,距离后弓左/右=(9.93±1.38)mm/(8.47±1.70)mm.个体间差异较大.结论:侧方椎弓螺钉固定的安全钉道在横断面经过横突孔区域(侧弓前份)中宽后界的内中1/3交界与中宽前界的外中1/3交界,矢状面经过后方中宽中部及前方中宽与关节突下界交界处,不同侧别间及不同个体间有明显差别.  相似文献   
7.
The Eastern Mediterranean Region (EMR) is experiencing a nutrition transition, characterized by the emergence of overnutrition and micro-nutrient deficiencies. No previous study has comparatively examined nutrient intake in adults across countries in the EMR. This review examined the adequacy of nutrients in adults living in the EMR. Moreover, it analyzed the food balance sheets (FBS) for 1961–2018 to identify the trajectory of energy supply from macro-nutrients in the EMR. A systematic search was conducted from January 2012 to September 2020. Only observational studies were retained with a random sampling design. An assessment of the methodological quality was conducted. Levels of nutrient daily intake and their adequacy compared to the daily reference intake of the Institute of Medicine were reported across the region. No studies were identified for half of the region’s countries. Although nutrient energy intake was satisfactory overall, fat and carbohydrate intake were high. Intake of vitamin D, calcium, potassium, zinc, and magnesium were below that recommended. The analysis of the FBS data allowed for the identification of four linear patterns of trajectories, with countries in the EMR best fitting the ‘high-energy-supply from carbohydrate’ group. This systematic review warrants multi-sectorial commitment to optimize nutrient intake.  相似文献   
8.
ObjectiveAfter diagnosis of Alzheimer's disease and related syndromes (ADRS), personalized care adapted to each patient's needs is recommended to provide a care plan and start symptomatic treatments according to guidelines. Over the past decade, dedicated structures and care have been implemented in various settings. Equal access to ADRS care, health care providers and services is crucial to ensure potential health benefits for everyone. However, the extent of use of recommended services and favorable health care utilization trajectories (HUT) may vary according to individual and contextual characteristics. The aim of this article was to (1) describe HUT patterns after multidimensional clustering of similar trajectories, (2) assess the proportion of individuals presenting favorable HUTs, and (3) identify factors associated with favorable HUTs.DesignCohort study.Setting and participantsA cohort of 103,317 people newly diagnosed with ADRS identified in the French health reimbursement system (SNDS) was followed for 5 years with their monthly utilization on 11 health care dimensions.MethodsFor 3 age groups (65–74, 75–84, ≥85 years), 15 clusters of patients were identified using partitioning around medoids applied to Levenshtein distances. They were qualitatively assessed by pluridisciplinary experts. Individual and contextual determinants of clusters denoting favorable trajectories were identified using mixed random effects multivariable logistic regression models.ResultsClusters with favorable HUTs denoting slow, progressive trajectories centered on at-home care, represented approximatively 25% of the patients. Determinants of favorable HUTs were mostly individual (age, female gender, absence of certain comorbidities, circumstances of ADRS identification, lower deprivation). Contextual determinants were also identified, in particular accessibility to nurses and nursing homes. Inter-territories variance was small but significant in all age groups (from 0.9% to 1.8%).Conclusion and implicationsFavorable HUTs remain the minority and many efforts can still be made to improve HUTs. Qualitative studies could help understanding underlying barriers to favorable HUTs.  相似文献   
9.
ObjectivesMalnutrition and cognitive impairment are associated with poor functional recovery in older adults following hip-fracture surgery. This study examined the combined effects of cognitive impairment and nutritional trajectories on postoperative functional recovery for older adults following hip-fracture surgery.DesignProspective longitudinal correlational study.Setting and ParticipantsThis study recruited 350 older adults (≥60 years of age) who received hip-fracture surgery at a 3000-bed medical center in northern Taiwan from September 2012 to March 2020.MethodsParticipant data were collected over a 2-year period after surgery for nutritional and cognitive status and activities of daily living (ADLs). Participants were grouped by type of nutritional trajectory using group-based trajectory modeling. Generalized estimating equations analyzed associations between trajectory groups/cognitive status at discharge and performance of ADLs.ResultsNutritional trajectories best fit a 3-group trajectory model: malnourished (19%), at-risk of malnutrition (40%), and well-nourished (41%). Nutritional status for the malnourished group declined from 12 months to 24 months following surgery; nutritional status remained stable for at-risk of malnutrition and well-nourished groups. Interactions for cognitive impairment-by-nutritional status were significant: the malnourished + intact cognition subgroup had significantly better ADLs than the malnourished + cognitive impairment subgroup (b = 27.1, 95% confidence interval = 14.0–40.2; P < .001). For at-risk of malnutrition and well-nourished groups, there were no significant differences between cognitive impairment and intact cognition in ADLs. These findings suggest that nutritional status may buffer the negative effect of cognitive impairment on ADLs.Conclusions and ImplicationsBetter nutritional status over time for older adults following hip fracture can protect against adverse influences of cognitive impairment on ADLs during postoperative recovery. Participants with malnutrition and cognitive impairment had the poorest ADLs. These findings suggest interventions tailored to improving nutritional status may improve recovery for older adults following hip-fracture surgery.  相似文献   
10.
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