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   27490篇
  免费   2099篇
  国内免费   704篇
耳鼻咽喉   670篇
儿科学   240篇
妇产科学   235篇
基础医学   4619篇
口腔科学   628篇
临床医学   1819篇
内科学   2402篇
皮肤病学   384篇
神经病学   4224篇
特种医学   1682篇
外国民族医学   3篇
外科学   2762篇
综合类   2737篇
一般理论   4篇
预防医学   1771篇
眼科学   1635篇
药学   2590篇
  12篇
中国医学   686篇
肿瘤学   1190篇
  2023年   312篇
  2022年   418篇
  2021年   818篇
  2020年   798篇
  2019年   767篇
  2018年   799篇
  2017年   792篇
  2016年   811篇
  2015年   765篇
  2014年   1342篇
  2013年   1727篇
  2012年   1420篇
  2011年   1483篇
  2010年   1313篇
  2009年   1281篇
  2008年   1391篇
  2007年   1310篇
  2006年   1241篇
  2005年   1035篇
  2004年   966篇
  2003年   805篇
  2002年   717篇
  2001年   666篇
  2000年   558篇
  1999年   487篇
  1998年   509篇
  1997年   472篇
  1996年   413篇
  1995年   400篇
  1994年   332篇
  1993年   320篇
  1992年   317篇
  1991年   302篇
  1990年   255篇
  1989年   243篇
  1988年   248篇
  1987年   211篇
  1986年   210篇
  1985年   350篇
  1984年   275篇
  1983年   218篇
  1982年   222篇
  1981年   217篇
  1980年   185篇
  1979年   138篇
  1978年   104篇
  1977年   81篇
  1976年   79篇
  1975年   36篇
  1974年   32篇
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
41.
《Clinical neurophysiology》2020,131(11):2641-2650
ObjectiveTo assess excitability differences between motor and sensory axons of affected nerves in patients with multifocal motor neuropathy (MMN).MethodsWe performed motor and sensory excitability tests in affected median nerves of 20 MMN patients and in 20 age-matched normal subjects. CMAPs were recorded from the thenar and SNAPs from the 3rd digit. Clinical tests included assessment of muscle strength, two-point discrimination and joint position.ResultsAll MMN patients had weakness of the thenar muscle and normal sensory tests. Motor excitability testing in MMN showed an increased threshold for a 50% CMAP, increased rheobase, decreased stimulus-response slope, fanning-out of threshold electrotonus, decreased resting I/V slope, shortened refractory period, and more pronounced superexcitability. Sensory excitability testing in MMN revealed decreased accommodation half-time and S2-accommodation and less pronounced subexcitability. Mathematical modeling indicated increased Barrett-Barrett conductance for motor fibers and increase in internodal fast potassium conductance for sensory fibers.ConclusionsExcitability findings in MMN suggest myelin sheath or paranodal seal involvement in motor fibers and, possibly, paranodal detachment in sensory fibers.SignificanceExcitability properties of affected nerves in MMN differ between motor and sensory nerve fibers.  相似文献   
42.
Immune checkpoint inhibitors (ICIs) have dramatically changed the strategy used to treat patients with non‐small‐cell lung cancer (NSCLC); however, the vast majority of patients eventually develop progressive disease (PD) and acquire resistance to ICIs. Some patients experience oligoprogressive disease. Few retrospective studies have evaluated clinical efficacy in patients with oligometastatic progression who received local therapy after ICI treatment. We conducted a retrospective analysis of advanced NSCLC patients who received PD‐1 inhibitor monotherapy with nivolumab or pembrolizumab to evaluate the effects of ICIs on the patterns of progression and the efficacy of local therapy for oligoprogressive disease. Of the 307 patients treated with ICIs, 148 were evaluated in our study; 42 were treated with pembrolizumab, and 106 were treated with nivolumab. Thirty‐eight patients showed oligoprogression. Male sex, a lack of driver mutations, and smoking history were significantly correlated with the risk of oligoprogression. Primary lesions were most frequently detected at oligoprogression sites (15 patients), and 6 patients experienced abdominal lymph node (LN) oligoprogression. Four patients showed evidence of new abdominal LN oligometastases. There was no significant difference in overall survival (OS) between the local therapy group and the switch therapy group (reached vs. not reached, P = .456). We summarized clinical data on the response of oligoprogressive NSCLC to ICI therapy. The results may help to elucidate the causes of ICI resistance and indicate that the use of local therapy as the initial treatment in this setting is feasible treatment option.  相似文献   
43.
Aim of studyThis is a retrospective study aimed at evaluating the effectiveness of the use of electromagnetic fields and negative pressure treatment (V-EMF) for facial scars, from an aesthetic and functional point of view, and considering the variations in the levels of hydration.Material and methods25 subjects with facial scarring were re-evaluated after being treated with the V-EMF method. The hydration levels of the scars before and after treatment were compared. The results were evaluated considering the satisfaction levels of the patients with the VAS, and of the medical specialists who performed the treatment, and of 3 independent dermatologists with the Likert scale.ResultsMean hydration levels of scars went from 41.8 to 53.3, with mean hydration levels of healthy reference points equal to 54.6. The minimum patient satisfaction level was 2 in the VAS. The minimum level of satisfaction of specialists and dermatologists was equal to IV on the Likert scale for all patients, except for 1 subject in which it was III for the specialist who had treated him. Anti-aging and re-pigmentation effects were also noted as secondary results.ConclusionsFrom an aesthetic and functional point of view, and for the overall anti-aging effect of the treated area, V-EMF applied to facial scars has shown extremely promising results.  相似文献   
44.
45.
46.
47.
目的利用UPLC-LTQ-Orbitrap-MS技术对刺果番荔枝叶的化学成分进行定性分析。方法采用Waters Acquity UPLC HSS T 3色谱柱(2.1 mm×100 mm,1.8μm),流动相为0.1%甲酸水(A)和乙腈(B)梯度洗脱,流速为0.3 mL/min,进样量2μL,在电喷雾正负离子模式下采集数据。经Reaxys数据库检索番荔枝属类化合物信息,通过质谱信息比对各化合物的m/z值、保留时间、质谱特征碎片等,并结合文献数据对鉴定的化合物进行验证。结果根据各化合物的特征裂解规律,从刺果番荔枝叶中共鉴定出45个化合物,包括16个生物碱类,14个番荔枝内酯类,7个黄酮类和8个其他类化合物,其中以番荔枝内酯类和生物碱类成分居多,与文献报道番荔枝内酯与生物碱类化合物是发挥抗癌的主要活性成分一致。结论利用UPLC-LTQ-Orbitrap-MS技术对刺果番荔枝叶中的化学成分进行了快速、准确的定性分析,为刺果番荔枝叶的提取分离与药效物质基础的研究提供依据。  相似文献   
48.
ObjectivesTo characterize and compare the stability of cortical potentials evoked by deep brain stimulation (DBS) of the subthalamic nucleus (STN) across the naïve, parkinsonian, and pharmacologically treated parkinsonian states. To advance cortical potentials as possible biomarkers for DBS programming.Materials and MethodsSerial electrocorticographic (ECoG) recordings were made more than nine months from a single non-human primate instrumented with bilateral ECoG grids spanning anterior parietal to prefrontal cortex. Cortical evoked potentials (CEPs) were generated through time-lock averaging of the ECoG recordings to DBS pulses delivered unilaterally in the STN region using a chronically implanted, six-contact, scaled DBS lead. Recordings were made across the naïve followed by mild and moderate parkinsonian conditions achieved by staged injections of the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxin. In addition to characterizing the spatial distribution and stability of the response within each state, changes in the amplitude and latency of CEP components as well as in the frequency content were examined in relation to parkinsonian severity and dopamine replacement.ResultsIn the naïve state, the STN DBS CEP presented as a multiphase response maximal over M1 cortex, with components attributable to physiological activity distinguishable from stimulus artifact as early as 0.45–0.75 msec poststimulation. When delivered using therapeutically effective parameters in the parkinsonian state, the CEP was highly stable across multiple recording sessions within each behavioral state. Across states, significant differences were present with respect to both the latency and amplitude of individual response components, with greater differences present for longer-latency components (all p < 0.05). Power spectral density analysis revealed a high-beta peak within the evoked response, with significant changes in power between disease states across multiple frequency bands.ConclusionsOur findings underscore the spatiotemporal specificity and relative stability of the DBS-CEP associated with different disease states and with therapeutic benefit. DBS-CEP may be a viable biomarker for therapeutic programming.  相似文献   
49.
目的:评价地塞米松不同给药途径(冠周局部注射和口服)在预防下颌阻生第三磨牙拔除术后肿胀、疼痛及张口受限中的疗效。方法:对480例患者的下颌阻生第三磨牙根据阻生类型进行分组(高位、中位、低位),每组中再分为实验组(拔牙术后局部注射地塞米松)和对照组(拔牙术后口服地塞米松),对患者术后第1、3、7天进行随访分析,对患者肿胀指数、疼痛程度和张口受限程度进行统计分析。结果:在拔牙术后第1天和第7天,高位组、中位组和低位组中的实验组与对照组在肿胀指数、疼痛程度和张口受限程度方面比较差异无统计学意义(P>0.05);术后第3天,高位组和中位组中的实验组与对照组在肿胀指数、疼痛程度和张口受限程度差异无统计学意义(P>0.05),低位组中的实验组与对照组相比,在肿胀反应中具有更好的预防效果(P<0.05),在疼痛程度和张口受限程度中具有一定的缓解效果(P>0.05)。结论:下颌阻生第三磨牙拔除术后,冠周局部给予地塞米松能够防治和减轻术后肿胀、疼痛以及张口受限的发生。  相似文献   
50.
目的探讨生物反馈电刺激联合补中益气汤对产妇产后盆底康复效果的影响。方法将56例初产妇按随机数字表法分成对照组与研究组各28例。对照组给予补中益气汤治疗;研究组在对照组基础上联合生物反馈电刺激治疗,两组均治疗6周。观测盆底肌相关电压、盆底肌力、尿失禁率、性生活质量。结果治疗后,两组盆底电位均值均显著升高,研究组高于对照组(P<0.05);治疗后,研究组尿失禁发生率显著降低,且显著低于对照组(P<0.05);研究组Ⅱ、Ⅲ、IV级肌力显著低于对照组(P<0.05);研究组性生活质量高水平显著高于对照组(P<0.05)。结论生物反馈电刺激联合补中益气汤可有效促进产妇产后盆底康复,效果显著优于单独补中益气汤。  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