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   207060篇
  免费   20279篇
  国内免费   13351篇
耳鼻咽喉   1863篇
儿科学   2227篇
妇产科学   2613篇
基础医学   24259篇
口腔科学   3926篇
临床医学   26994篇
内科学   29674篇
皮肤病学   2452篇
神经病学   10520篇
特种医学   7427篇
外国民族医学   106篇
外科学   20842篇
综合类   35446篇
现状与发展   45篇
一般理论   23篇
预防医学   14545篇
眼科学   5298篇
药学   22414篇
  229篇
中国医学   12773篇
肿瘤学   17014篇
  2024年   701篇
  2023年   3000篇
  2022年   8546篇
  2021年   10928篇
  2020年   8234篇
  2019年   6935篇
  2018年   7344篇
  2017年   6893篇
  2016年   6311篇
  2015年   9826篇
  2014年   12042篇
  2013年   11263篇
  2012年   16716篇
  2011年   17960篇
  2010年   11875篇
  2009年   9177篇
  2008年   11918篇
  2007年   11178篇
  2006年   10602篇
  2005年   10188篇
  2004年   6663篇
  2003年   5984篇
  2002年   4917篇
  2001年   4120篇
  2000年   4188篇
  1999年   4138篇
  1998年   2446篇
  1997年   2469篇
  1996年   1914篇
  1995年   1851篇
  1994年   1628篇
  1993年   976篇
  1992年   1347篇
  1991年   1176篇
  1990年   936篇
  1989年   870篇
  1988年   782篇
  1987年   622篇
  1986年   466篇
  1985年   409篇
  1984年   194篇
  1983年   165篇
  1982年   96篇
  1981年   123篇
  1980年   79篇
  1979年   110篇
  1978年   52篇
  1977年   52篇
  1976年   42篇
  1974年   44篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
BACKGROUND AND PURPOSE:Cognitive challenges are prevalent in survivors of glioma, but their neurobiology is incompletely understood. The purpose of this study was to investigate the effect of glioma presence and tumor characteristics on resting-state functional connectivity and amplitude of low-frequency fluctuations of the salience network, a key neural network associated with cognition.MATERIALS AND METHODS:Sixty-nine patients with glioma (mean age, 48.74 [SD, 14.32] years) who underwent resting-state fMRI were compared with 31 healthy controls (mean age, 49.68 [SD, 15.54] years). We identified 4 salience network ROIs: left/right dorsal anterior cingulate cortex and left/right anterior insula. Average salience network resting-state functional connectivity and amplitude of low-frequency fluctuations within the 4 salience network ROIs were computed.RESULTS:Patients with gliomas showed decreased overall salience network resting-state functional connectivity (P = .001) and increased amplitude of low-frequency fluctuations in all salience network ROIs (P < .01) except in the left dorsal anterior cingulate cortex. Compared with controls, patients with left-sided gliomas showed increased amplitude of low-frequency fluctuations in the right dorsal anterior cingulate cortex (P = .002) and right anterior insula (P < .001), and patients with right-sided gliomas showed increased amplitude of low-frequency fluctuations in the left anterior insula (P = .002). Anterior tumors were associated with decreased salience network resting-state functional connectivity (P < .001) and increased amplitude of low-frequency fluctuations in the right anterior insula, left anterior insula, and right dorsal anterior cingulate cortex. Patients with high-grade gliomas had decreased salience network resting-state functional connectivity compared with healthy controls (P < .05). The right anterior insula showed increased amplitude of low-frequency fluctuations in patients with grade II and IV gliomas compared with controls (P < .01).CONCLUSIONS:By demonstrating decreased resting-state functional connectivity and an increased amplitude of low-frequency fluctuations related to the salience network in patients with glioma, this study adds to our understanding of the neurobiology underpinning observable cognitive deficits in these patients. In addition to more conventional functional connectivity, amplitude of low-frequency fluctuations is a promising functional-imaging biomarker of tumor-induced vascular and neural pathology.

Detrimental effects of cancer on cognitive function and, consequently, on the quality of life are emerging as a key focus of cancer survivorship both in research and clinical practice.1,2 Brain tumors have been shown to affect memory, processing, and attention in patients; however, their underlying neurobiology is incompletely understood.3 Using resting-state functional MR imaging (rsfMRI) to evaluate changes in cognitive resting-state networks may provide a better understanding of the pathology underlying the observable cognitive disruptions in gliomas, the most common primary brain tumor in adults.A “triple network model” of neurocognitive pathology has been proposed, which encompasses the default mode network, involved in mind wandering; the central executive network, involved in decision-making; and the salience network (SN), implicated in modulating activation of the default mode network and central executive network by detecting the presence of salient stimuli.4-8 While previous rsfMRI research has largely focused on tumor-induced changes in the default mode network,9,10 our study examined the less-studied SN, a network rooted in the anterior insula and the dorsal anterior cingulate cortex.6Prior studies evaluating gliomas and SN resting-state functional connectivity (RSFC) provided conflicting results in small patient samples: Maesawa et al10 found no significant differences in the SN in 12 patients, while Liu et al11 more recently found decreased SN connectivity in 13 patients. Gliomas impact the integrity of the neurovascular unit to varying degrees, resulting in neurovascular uncoupling that has been reported to confound fMRI interpretations in patients with brain tumors.12-14 Additionally, research has reported neuronal plasticity manifested by structural reorganization and functional remodeling of neural networks in patients with gliomas with possible alterations in clinically observable cognitive manifestations.15-17 An rsfMRI metric, the amplitude of low-frequency fluctuations (ALFF), has recently shown promise as a biomarker for brain plasticity and hemodynamic characterization, including neurovascular uncoupling in patients with gliomas.15-19The purpose of this study was to investigate the effect of glioma presence and tumor characteristics on overall RSFC and regional normalized ALFF within the SN in a large patient population. We hypothesized that there would be decreased average SN RSFC and altered ALFF in patients with gliomas compared with healthy controls. Recent studies have acknowledged that gliomas have variable effects on network integrity based on lesion location and proximity to network ROIs,20-22 and unilateral gliomas can be associated with plasticity in both the ipsilateral and contralateral hemispheres.11,17 Research also supports differences in resting-state network reorganization in aggressive high-grade gliomas compared with slower-growing low-grade gliomas.20,23 Therefore, we also hypothesized that there would be differences in average SN RSFC and regional ALFF in patients based on the anterior-versus-posterior location, hemispheric side, and grade of glioma.  相似文献   
122.
刘培  杨芳  李静 《护理学杂志》2019,34(10):105-109
体外膜肺氧合成为治疗严重心、肺衰竭患者的一种新方法并在重症患者中逐渐应用,而早期活动可促进危重患者康复。本文就近年来关于成人体外膜肺氧合患者早期活动的意义、安全性、开展情况及主要障碍、实施流程、实施策略等进行综述,为促进体外膜肺氧合患者早期活动的开展、改善预后提供参考。  相似文献   
123.
124.
ObjectivesTo investigate the effect of corneal stromal pocket irrigation after small-incision lenticule extraction (SMILE) on visual acuity, intraocular pressure (IOP), corneal parameters and complications after surgery.MethodsA total of 242 eyes of 121 patients undergoing SMILE were enrolled in this prospective controlled study, and it was designed for one eye to randomly undergo SMILE with balanced salt solution irrigation of the corneal stromal pocket, while the other eye was not. The uncorrected distance visual acuity (UDVA) and slit lamp examination were recorded at 1 hour, 1 day, 1 week, and 1 month. Postoperative corneal density, corneal biomechanical, corneal endothelial cell number, and anterior OCT images were compared at 1 day, 1 week, and 1 month.ResultsCompared with the nonirrigation group, the irrigation group showed significantly higher UDVA at 1 day postoperatively (P < 0.05), but there was no significant difference during the rest of the postoperative period (1 hour, 1 week, and 1 month). In addition, no significant differences were found in IOP, corneal density, corneal biomechanics, corneal endothelial cells, and corneal morphology. No visual decline or severe postoperative complications were found in the patients in this study.ConclusionsInterlamellar irrigation did not affect IOP, corneal parameters, morphology, complications, or UDVA at 1 hour, 1 week, and 1 month after the operation, but it may promote UDVA 1 day after the operation.Subject terms: Refractive errors, Outcomes research, Surgery  相似文献   
125.
目的研制加强型鼻咽通气道应用于五官科鼻腔手术后的气道管理。方法选取2014年1月至2015年3月行五官科鼻腔手术的患者60例,将其分为A组和B组,各30例。A组作为加强型鼻咽通气道组,术毕在膨胀止血海绵中放置加强型鼻咽通气道保留鼻腔通气;B组作为对照组,术毕采用传统单纯填塞膨胀止血海绵。通过术后24、48 h随访,对两组患者进行疼痛、睡眠质量、口干程度评分,并对其进行对比分析。结果加强型鼻咽通气道具有良好的抗压抗折性;A组患者24、48 h睡眠质量、口干程度评分均明显优于B组,差异均有统计学意义(P<0.05)。结论加强型鼻咽通气道用于五官科鼻腔手术后气道管理可增强气道管理安全性及患者舒适度。  相似文献   
126.
目的调查呼吸专科护士慢性呼吸疾病管理现状,为提高慢性呼吸疾病的管理水平提供参考。方法依据《中国成人慢性呼吸疾病患者护理管理指南》设计调查问卷,对重庆、四川、贵州、陕西、河北、湖北、海南7省市的205名呼吸专科护士进行问卷调查。结果呼吸专科护士慢性呼吸疾病管理总分为(140.72±23.90)分。慢性呼吸疾病管理得分最低的3个条目有评估工具应用、个性化管理计划的实施、慢阻肺随访的次数及指导哮喘患者使用峰流速仪;呼吸专科护士所在单位慢性呼吸疾病管理平台建设均低于50%。结论呼吸专科护士慢性呼吸疾病管理处于中等偏下水平,评估是慢性呼吸疾病管理的薄弱点。需加强呼吸专科护士专业能力培养,规范慢性呼吸疾病全程管理,强化医院平台建设等,提高慢性呼吸疾病的管理水平。  相似文献   
127.
目的:探究超脉冲CO2点阵激光联合富血小板血浆(PRP)治疗面部痤疮凹陷性瘢痕的疗效。方法:72例面部痤疮凹陷性瘢痕患者,随机分为观察组(36例)和对照组(36例)。对照组采用超脉冲CO2点阵激光治疗,观察组采用超脉冲CO2点阵激光联合PRP治疗。比较两组患者的灰度差异、时间指标、瘢痕程度、疼痛、不良反应及视觉评估。结果:观察组的并发症发生率为11.11%,低于对照组的36.11%,差异具有统计学意义(P<0.05)。治疗后,两组患者的灰度差异率均减小,且观察组患者的灰度差异率显著低于对照组,差异具有统计学意义(P<0.05)。治疗后,观察组的炎性渗出时间、红肿时间、愈合时间、停工时间及瘢痕程度评分均低于对照组,差异均具有统计学意义(P<0.05);但疼痛度评分组间比较,差异无统计学意义(P>0.05)。结论:超脉冲CO2点阵激光联合PRP治疗面部痤疮凹陷性瘢痕效果较好,可有效降低瘢痕程度,减少治疗时间及并发症的发生,帮助患者迅速回归正常工作与生活,值得临床推广使用。  相似文献   
128.
目的应用6σ理论对肿瘤标志物项目的分析性能进行评价,并初步确定各项目的质量目标。 方法收集本实验室2018年1至12月室内质控数据和国家卫生健康委临床检验中心室间质量评价结果,以生物学变异导出的质量规范和国家室间质量评价标准作为允许总误差(TEa)计算6项肿瘤标志物的σ水平,并依据质量目标选择流程图和肿瘤标志物分析性能验证图评价肿瘤标志物的分析性能,进而为肿瘤标志物选择合适的质量目标。 结果应用不同层级的生物学变异导出的质量规范和国家室间质量评价标准,肿瘤标志物项目的σ水平存在显著差异;依据质量目标选择流程图:选择生物学变异导出的"适当的"质量规范作为CA125项目的质量目标,选择生物学变异导出的"最低的"质量规范作为t-PSA、CEA、AFP、CA199和CA153项目的质量目标。 结论6σ能够客观评价肿瘤标志物的分析性能,并为实验室质量目标的选择提供重要的参考价值。  相似文献   
129.
随着医改的不断深入和建立现代医院管理制度的迫切要求,公立医院面临全新的挑战,向管理要效益是实现医院内涵式发展的重要途径。从当前公立医院运营管理的现状入手,通过深入分析存在的问题,为进一步推进公立医院运营管理建设提出思路和建议,对实现公立医院管理转型,提升医院管理水平,实现科学化、精益化管理提供借鉴。  相似文献   
130.
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