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   1203篇
  免费   96篇
  国内免费   28篇
耳鼻咽喉   4篇
儿科学   3篇
妇产科学   16篇
基础医学   218篇
口腔科学   200篇
临床医学   206篇
内科学   34篇
皮肤病学   4篇
神经病学   276篇
特种医学   25篇
外科学   106篇
综合类   92篇
预防医学   59篇
眼科学   20篇
药学   33篇
  1篇
中国医学   16篇
肿瘤学   14篇
  2024年   2篇
  2023年   36篇
  2022年   56篇
  2021年   47篇
  2020年   49篇
  2019年   63篇
  2018年   56篇
  2017年   50篇
  2016年   52篇
  2015年   46篇
  2014年   72篇
  2013年   93篇
  2012年   67篇
  2011年   70篇
  2010年   54篇
  2009年   57篇
  2008年   52篇
  2007年   64篇
  2006年   41篇
  2005年   58篇
  2004年   41篇
  2003年   29篇
  2002年   37篇
  2001年   16篇
  2000年   15篇
  1999年   21篇
  1998年   15篇
  1997年   13篇
  1996年   4篇
  1995年   3篇
  1994年   3篇
  1993年   4篇
  1992年   2篇
  1991年   1篇
  1990年   6篇
  1989年   7篇
  1988年   2篇
  1987年   3篇
  1986年   2篇
  1985年   2篇
  1984年   2篇
  1982年   3篇
  1980年   4篇
  1979年   1篇
  1976年   1篇
  1974年   1篇
  1972年   1篇
  1971年   1篇
  1968年   1篇
  1966年   1篇
排序方式: 共有1327条查询结果,搜索用时 15 毫秒
1.
ObjectivesThis study was conducted to compare the healing response of localized gingival recession defects treated with a coronally advanced flap (CAF) and either an amnion allograft membrane (AM) or a connective tissue graft (CTG).MethodsGingival recession defects were surgically created in six healthy mongrel dogs at the labial root surface of the maxillary canines, bilaterally. Using a split mouth design, the defects were treated with CAF and either AM (CAF/AM) or CTG (CAF/CTG). Three animals for each group were scarified at 1 and 3 months. Segments containing the defects were prepared for histological and histometric analysis.ResultsBoth techniques showed similar clinical findings with adequate root coverage. Histologically, healing was characterized by the formation of new cementum and new connective tissue attachment in the CAF/AM group; in the CAF/CTG group, healing was characterized by junctional epithelium, coronally, and connective tissue fibers parallel to the root surface, apically. Histometrically, the CAF/AM group revealed a substantially shorter epithelial length and a longer, new cementum compared with those of the CAF/CTG group after a healing period of 3 months.ConclusionsWithin the limits of this study, we concluded that the AM allograft could promote periodontal healing in gingival recession defects.  相似文献   
2.
目的 探讨引导想象训练对老年髋关节置换术患者疼痛、睡眠情况和精神状态的影响。方法 选取2020年6月~2020年10月某三甲医院收治的拟行髋关节置换手术的老年患者90例,采用随机数字表法将其分为对照组(n=46)和试验组(n=44)。对照组给予基于ERAS的围手术期护理,试验组在对照组的基础上进行运动引导想象训练。分别在术前、术后当天、术后第1天、术后第3天和术后第7天采用疼痛数字分级法(NRS)、理查兹-坎贝尔睡眠量表(RCSQ)和简易智能精神状态评价量表(MMSE)测评患者的疼痛、睡眠及精神状况;同时使用护理谵妄评分(NU_DESC)判断患者住院期间是否发生谵妄。结果 共有87例患者完成研究,总完成率为96.67%。重复测量方差分析结果显示两组患者疼痛、睡眠及精神变化存在时间效应、组间效应及交互效应;术后试验组谵妄发生率低于对照组,差异均有统计学意义(P<0.05)。结论 运动引导想象训练有助于改善老年全髋关节置换患者的疼痛程度、睡眠情况和精神状态。  相似文献   
3.
ObjectivesIntraoperative visualization of gliomas with 5-aminolevulinic acid (5-ALA) induced fluorescence constitutes a powerful technique. While visible fluorescence is typically observed in high-grade gliomas, fluorescence is considerably less common in lower-grade gliomas (LGGs) WHO grade II&III. Whereas the exact mechanisms determining fluorescence in LGGs are not fully understood, metabolization of non-fluorescent 5-ALA to fluorescent Protoporphyrin IX by specific heme biosynthesis enzymes/transporters has been identified as relevant mechanism influencing fluorescence behavior. Furthermore, recent in-vitro studies have suggested preoperative treatment with corticosteroids and anti-epileptic drugs (AED) as potential factors influencing 5-ALA induced fluorescence.MethodsThe goal of this study was thus to investigate the effect of preoperative corticosteroid/AED treatment on heme biosynthesis mRNA expression in a clinically relevant patient population. For this purpose, we analyzed the mRNA expression levels of specific heme biosynthesis factors including ALAD, HMBS, UROS, UROD, CPOX, PPOX, FECH, ABCB6, ACG2, SLC15A1 and SLC15A2, ABCB1, ABCB10 in a cohort of LGGs from “The Cancer Genome Atlas”.ResultsAltogether, 403 patients with available data on preoperative corticosteroid/AED treatment and heme biosynthesis mRNA expression were identified. Regarding corticosteroid treatment, no significant differences in expression of any of the 11 investigated heme biosynthesis factors were found. In contrast, a marginal yet statistically significant increase in SLC15A1 levels and decrease in ABCB6 levels were observed in patients with preoperative AED treatment.ConclusionWhile no significant differences in heme biosynthesis mRNA expression were observed according to preoperative corticosteroid treatment, changes in SLC15A1 as well as ABCB6 expression were detected in patients treated with AED. However, since these alterations were minor and have opposing effects on 5-ALA metabolization, our findings do not support a distinct effect of AED and corticosteroid treatment on heme biosynthesis regulation in LGGs.  相似文献   
4.
The aim of this study was to investigate the accuracy of a previously described technique for guided biopsy of osseous pathologies of the jawbone in a clinical setting. The data sets of patients who had undergone guided biopsy procedures were retrospectively examined for accuracy. Digital planning of the biopsies and manufacturing of the tooth-supported drilling template were performed with superimposed cone beam computed tomography and intraoral scans using implant planning software. After a trephine biopsy was taken using the template, the postoperative low-dose cone beam computed tomography was analyzed for accuracy using the planning software with the corresponding (digitally-planned) biopsy cylinder. The mean angular deviation was 4.35 ± 2.5°. The mean depth deviation was ?1.40 ± 1.41 mm. Guided biopsy seems to be an alternative to a conventional approach for minimally invasive and highly accurate jawbone biopsy.  相似文献   
5.
Motor imagery is defined as an act wherein an individual contemplates a mental action of motor execution without apparent action. Mental practice executed by repetitive motor imagery can improve motor performance without simultaneous sensory input or overt output. We aimed to investigate cerebral hemodynamics during motor imagery and motor execution of a self-feeding activity using chopsticks. This study included 21 healthy right-handed volunteers. The self-feeding activity task comprised either motor imagery or motor execution of eating sliced cucumber pickles with chopsticks to examine eight regions of interest: pre-supplementary motor area, supplementary motor area, bilateral prefrontal cortex, premotor area, and sensorimotor cortex. The mean oxyhemoglobin levels were detected using near-infrared spectroscopy to reflect cerebral activation. The mean oxyhemoglobin levels during motor execution were significantly higher in the left sensorimotor cortex than in the supplementary motor area and the left premotor area. Moreover, significantly higher oxyhemoglobin levels were detected in the supplementary motor area and the left premotor area during motor imagery, compared to motor execution. Supplementary motor area and premotor area had important roles in the motor imagery of self-feeding activity. Moreover, the activation levels of the supplementary motor area and the premotor area during motor execution and motor imagery are likely affected by intentional cognitive processes. Levels of cerebral activation differed in some areas during motor execution and motor imagery of a self-feeding activity. This study was approved by the Ethical Review Committee of Nagasaki University(approval No. 18110801) on December 10, 2018.  相似文献   
6.
IntroductionThe use of motor imagery (MI) has been shown to offer significant improvements in movement performance in sports, and is now receiving a lot of attention as a relatively new therapeutic approach which can be applied in rehabilitation. However, the effects of MI on the quality of movement is still unclear. This study explored the immediate effect of MI on reaching tasks in healthy subjects.Methods17 healthy individuals (33 ± 8.2 years) participated in the study. Surface electromyography (sEMG) and inertial measurement units (IMU) were used to identify muscle activity and angular velocity in both upper limbs. Participants performed a reach task using their dominant and non-dominant arms at their most comfortable speed, they were then asked to imagine themselves performing the same reaching task, and finally they were asked to repeat the reaching task.ResultsSignificant decreases were seen in the muscle activity between pre and post MI for Biceps Brachii, Anterior Deltoid and Triceps Brachii. In addition, a significant increase was seen in extension angular velocity post MI.DiscussionThe results indicate that the use of MI just after physical practice appears to have an immediate effect on the muscle activity and kinematics during a reaching task, which may suggest an improved quality of movement.ConclusionThis proof of concept study shows the potential for MI to improve the quality of performing reaching task and offers a possible therapeutic option for Stroke survivors and other neuromuscular disorders.  相似文献   
7.
8.
利用脑网络研究经颅直流电刺激(tDCS)对脑功能机制和脑皮层状态的影响具有重要意义。本研究基于偏定向相干因果分析方法,构建被试在不同tDCS刺激实验范式下进行运动想象的因效性脑网络。以因效性脑网络的功能脑区通道信息流入、流出率为局部特征,平均聚类系数、全局效率为全局特征,分析研究tDCS对运动想象脑网络特征的影响。16名健康被试均为右利手。结果显示,被试执行左手运动想象下,伪刺激和阳极刺激C4后的C4通道信息流出率、流入率、平均聚类系数和全局效率分别为0.142±0.014、0.193±0.013、0.585±0.046、0.347±0.031和0.223±0.025、0.258±0.023、0.817±0.021、0.491±0.091,均存在显著性差异(P<0.05);tDCS阴极刺激C4后的C4通道信息流出率、平均聚类系数和全局效率分别为0.109±0.009、0.356±0.037和0.252±0.024,与伪刺激相比差异显著(P<0.05),C4通道信息流入率为0.184±0.008,与伪刺激相比无显著差异(P>0.05)。研究表明,阳极tDCS有效激活该脑区皮层的活跃性,使脑区信息交流更加频繁,增加脑网络的聚集程度,提高脑网络的连通性;阴极tDCS刺激则会抑制脑区皮层的活跃性,降低了脑区信息的流出,减少脑网络的聚集程度,降低脑网络的连通性。  相似文献   
9.
10.
In this article, we examine the social management of fatness via an analysis of 4 years of participant‐observation in military‐style fitness boot camps and interviews with camp participants, trainers and organisers/owners. We begin by focusing on popular imagery of the ‘boot camp’. The boot camp model takes various forms; yet, whether it involves civilian participants, as on reality television shows, or the imagined military ones of films, the boot camp model emphasises the re‐fashioning of the individual via the disciplining of bodies and selves. Such constructions of boot camps were employed by our respondents to lay claim to identities which highlight their hard work, strength of character, fundamental ‘goodness’ and self‐discipline, as those qualities are demonstrated through the body – even though participants’ actual bodies change little at camp. Such meanings stand in direct contradiction to broader social constructions of fatness and participants’ own negative perceptions of fat people. Moreover, even within the camps themselves, such identity claims are contested, both by camp trainers and by slimmer and ‘fitter’ attendees. These counterclaims are grounded in ideas about the characterological implications of the fat body, beliefs about the purpose of boot camp and notions of the body's capacity for change.  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