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   22572篇
  免费   1657篇
  国内免费   332篇
耳鼻咽喉   276篇
儿科学   627篇
妇产科学   241篇
基础医学   2136篇
口腔科学   381篇
临床医学   3576篇
内科学   2363篇
皮肤病学   221篇
神经病学   5287篇
特种医学   461篇
外科学   1433篇
综合类   2567篇
一般理论   3篇
预防医学   2421篇
眼科学   127篇
药学   1411篇
  18篇
中国医学   664篇
肿瘤学   348篇
  2023年   527篇
  2022年   901篇
  2021年   1397篇
  2020年   1272篇
  2019年   1229篇
  2018年   1216篇
  2017年   1170篇
  2016年   959篇
  2015年   795篇
  2014年   1889篇
  2013年   2073篇
  2012年   1326篇
  2011年   1606篇
  2010年   1048篇
  2009年   1086篇
  2008年   1020篇
  2007年   862篇
  2006年   650篇
  2005年   510篇
  2004年   412篇
  2003年   358篇
  2002年   268篇
  2001年   239篇
  2000年   170篇
  1999年   141篇
  1998年   115篇
  1997年   90篇
  1996年   91篇
  1995年   88篇
  1994年   82篇
  1993年   80篇
  1992年   53篇
  1991年   47篇
  1990年   57篇
  1989年   31篇
  1988年   40篇
  1987年   33篇
  1985年   70篇
  1984年   65篇
  1983年   45篇
  1982年   52篇
  1981年   31篇
  1980年   43篇
  1979年   56篇
  1978年   40篇
  1977年   30篇
  1976年   40篇
  1975年   41篇
  1974年   29篇
  1973年   26篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Cognitive science continues to make a compelling case for having a coherent, unique, and fundamental subject of inquiry: What is the nature of minds, where do they come from, and how do they work? Central to this inquiry is the notion of agents that have goals, one of which is their own persistence, who use dynamically constructed knowledge to act in the world to achieve those goals. An agentive perspective explains why a special class of systems have a cluster of co‐occurring capacities that enable them to exhibit adaptive behavior in a complex environment: perception, attention, memory, representation, planning, and communication. As an intellectual endeavor, cognitive science may not have achieved a hard core of uncontested assumptions that Lakatos (1978) identifies as emblematic of a successful research program, but there are alternative conceptions according to which cognitive science has been successful. First, challenges of the early, core tenet of “Mind as Computation” have helped put cognitive science on a stronger foundation—one that incorporates relations between minds and their environments. Second, even if a full cross‐disciplinary theoretic consensus is elusive, cognitive science can inspire distant, deep, and transformative connections between pairs of fields. To be intellectually vital, cognitive science need not resemble a traditional discipline with its associated insularity and unchallenged assumptions. Instead, there is strength and resilience in the diverse perspectives and methods that cognitive science assembles together. This interdisciplinary enterprise is fragile and perhaps inherently unstable, as the looming absorption of cognitive science into psychology shows. Still, for many researchers, the excitement and benefits of triangulating on the nature of minds by integrating diverse cases cannot be secured by a stable discipline with an uncontested core of assumptions.  相似文献   
72.
ObjectivesGrowing evidence of the importance of motor competence for developing a healthy lifestyle has been established in the last decade. Nonetheless, no single instrument or observation tool have been able to fully measure this construct, particularly because most were built for the diagnosis of children in risk for motor impairment; are limited to a few years of the developmental span; lack objectivity in the assessment protocols; or do not include the locomotor, stability, and manipulative components. This led to the difficulty of comparing researches, and longitudinally follow children into adulthood. Recently, a novel proposal to assess motor competence was presented - the Motor Competence Assessment (MCA) - and this study aims to present the MCA normative data from 3-to-23 years.Design and methodsTwo thousand and eighty-seven participants (1102 boys) between 3 and 23 years of age were evaluated in the MCA (standing long jump, 10 m shuttle run, throwing velocity, kicking velocity, lateral jumps, shifting platforms). Results for each test were introduced in the LMS Chartmaker 2.3. The best model for test and sex was used, resulting in normative curves and percentile values.ResultsFinal norms showed a good fit to the instrument developmental expectations, allowing to differentiate and classify performances along the age interval.ConclusionsThe MCA age- and sex- normative values allow to assess motor competence from childhood to early adulthood. Future directions will include obtaining a total MCA score and the normative scores for the MCA components (stability, locomotion, object control), and to expand the norms to adulthood and old age.  相似文献   
73.

Objectives

The current study investigated the effects of two exercise interventions on cognitive function amongst breast cancer survivors.

Design

Pilot randomised-controlled trial.

Methods

Seventeen female cancer survivors (mean: 62.9 ± 7.8 years) were randomised into three groups: high-intensity interval training (HIIT, n = 6); moderate-intensity continuous training (MOD, n = 5); or wait-list control (CON, n = 6). The HIIT and MOD groups exercised on a cycle ergometer 3 days/week for 12-weeks. Primary outcomes were cognitive function assessments utilising CogState. Secondary outcomes were resting middle cerebral artery blood flow velocity, cerebrovascular reactivity and aerobic fitness (VO2peak). Data were analysed with General Linear Mixed Models and Cohen’s d effect sizes were calculated.

Results

All 17 participants who were randomised were available for follow-up analysis and adherence was similar for HIIT and MOD (78.7 ± 13.2% vs 79.4 ± 12.0%; p = 0.93). Although there were no significant differences in the cognitive and cerebrovascular outcomes, HIIT produced moderate to large positive effects in comparison to MOD and CON for outcomes including episodic memory, working memory, executive function, cerebral blood flow and cerebrovascular reactivity. HIIT significantly increased VO2peak by 19.3% (d = 1.28) and MOD had a non-significant 5.6% (d = 0.72) increase, compared to CON which had a 2.6% decrease.

Conclusions

This study provides preliminary evidence that HIIT may be an effective exercise intervention to improve cognitive performance, cerebrovascular function and aerobic fitness in breast cancer survivors. Considering the sample size is small, these results should be confirmed through larger clinical trials.  相似文献   
74.
BackgroundWhen older adults turn to sit, about 80% of the subjects complete the turn before starting to sit i.e., a distinct-strategy, while in about 20%, part of the turning and sitting take place concurrently, i.e., an overlapping-strategy. A prolonged duration of the separation between tasks in the distinct-strategy (D-interval) and a prolonged duration of the overlap interval in overlapping-strategy (O-interval) are related to worse motor symptoms and poorer cognition. In the present study, we evaluated what strategy is employed by patients with Parkinson’s disease (PD) when they transition from turning to sitting.Methods96 participants with PD performed turn to sit as part of the Timed Up and Go test, both with and without medications, while wearing a body-fixed sensor. We quantified the turn-to-sit transition and determined which strategy (distinct or overlapping) was employed. We then stratified the cases and used regression models adjusted for age, gender, height, and weight to examine the associations of the D-interval or O-interval with parkinsonian features and cognition.ResultsMost patients (66%) employed the overlapping-strategy, both off and on anti-parkinsonian medications. Longer O-intervals were associated with longer duration of PD, more severe PD motor symptoms, a higher postural-instability-gait-disturbance (PIGD) score, and worse freezing of gait. Longer D-intervals were not associated with disease duration or PD motor symptoms. Neither the D- nor O-intervals were related to cognitive function. Individuals who employed the overlapping-strategy had more severe postural instability (i.e., higher PIGD scores), as compared to those who used the distinct-strategy.SignificanceIn contrast to older adults without PD, most patients with PD utilize the overlapping strategy. Poorer postural and gait control are associated with the strategy choice and with the duration of concurrent performance of turning and sitting. Additional work is needed to further explicate the mechanisms underlying these strategies and their clinical implications.  相似文献   
75.
76.
ObjectivesEarly diagnosis of cognitive impairment is increasingly emphasized in the literature to facilitate timely preventive interventions. Although bedside cognitive tests such as the Montreal Cognitive Assessment (MoCA) are widely used for such early diagnostic purposes, they may not have comparable performance to a full neuropsychological battery (FNB) in diagnosing early cognitive impairment. This study investigated whether a small subset of neuropsychological tests can be added on to MoCA to match its performance to that of the FNB in discriminating mild cognitive impairment and dementia (MCI/dementia) from normal cognition.DesignCross-sectional diagnostic study.SettingAlzheimer's Disease Centers across the United States.ParticipantsOlder participants (≥50 years) who completed MoCA and the FNB (N = 9187).MeasuresThe study sample was split into two: the derivation sample (n = 1837) was used to develop a brief neuropsychological battery that best discriminated MCI/dementia (using the best-subset approach with 10-fold cross-validation); while the validation sample (n = 7350) verified its actual performance in discriminating MCI/dementia.ResultsA 3-item neuropsychological battery was identified, comprising MoCA, Benson Complex Figure Recall, and Craft Story 21 Delayed Recall. It had excellent performance in discriminating MCI/dementia from normal cognition (area under the receiver operating characteristic curve [AUROC] 90.0%, 95% confidence interval [CI] 89.2%-90.7%), which was comparable to that of the FNB (AUROC 88.4%, 95% CI 87.6%-89.2%). By contrast, MoCA alone had significantly worse AUROC (86.9%, 95% CI 86.0%-87.7%) than that of the FNB.Conclusions/ImplicationsUsing rigorous methods, this study developed a brief neuropsychological battery that maintained the brevity of a bedside cognitive test, while rivaling the diagnostic performance of an FNB in early cognitive impairment. This brief battery offers a viable alternative when the FNB is needed but cannot be feasibly administered in nonspecialty clinics. It can have a wider health systems effect of improving patients’ access to accurate diagnosis in early cognitive impairment and facilitating timely interventions to delay the progression of cognitive impairment.  相似文献   
77.
《中国现代医生》2020,58(20):96-99
目的 探讨强化认知训练在改善2型糖尿病(T2DM)患者认知功能障碍和日常生活活动能力中的作用。方法选取2017年1月~2018年12月该院内科就诊T2DM患者92例。采用抛银币法将其分为强化组与常规组,各46例。两组均在口服降糖药或皮下注射胰岛素等控制血糖基础治疗上予以口服尼莫地平片30 mg/次,3次/d。常规组予以常规干预措施,强化组在常规组基础上加用强化认知训练。两组均干预12周。评估两组干预前与干预12周后认知功能及日常生活活动指标的变化,并比较临床效果。结果 干预12周后,两组HDS评分、MOCA评分和WAISE评分较前均显著上升,FAQ评分和ADL评分较前显著下降(P0.05或P0.01),且强化组上升或下降幅度较常规组更明显(P0.05);同时强化组患者临床总有效率(95.65%)较常规组(82.61%)的效果更佳(χ2=4.04,P0.05)。结论 强化认知训练用于T2DM患者效果较肯定,不仅能显著改善患者的认知功能,而且有利于提高患者日常生活活动能力。  相似文献   
78.
目的观察至阳八阵穴隔附子饼灸治疗脾胃气虚型糖尿病胃轻瘫的疗效及对胃泌素(GAS)、胃动素(MTL)和血管活性肠肽(VIP)水平的影响。方法86例脾胃气虚型糖尿病胃轻瘫患者随机分为对照组和治疗组,每组43例。治疗组给予至阳八阵穴隔附子饼灸;对照组口服枸橼酸莫沙必利片。治疗12周后观察胃轻瘫主要症状指数量表症状积分改善情况、胃排空率及血清GAS、MTL、VIP水平。结果治疗组治疗后在胃轻瘫主要症状指数量表症状积分及胃排空率方面明显高于对照组,差异均有统计学意义(P<0.05)。治疗组治疗后血清GAS、MTL水平明显高于对照组,血清VIP水平明显低于对照组,差异均有统计学意义(P<0.05)。治疗组总有效率为90.7%,明显高于对照组的72.1%(P<0.05)。结论采用至阳八阵穴隔附子饼灸能快速促进糖尿病胃轻瘫患者胃功能的恢复,改善症状和体征,其作用机制可能与升高患者血清GAS和MTL水平,降低VIP水平有关。  相似文献   
79.
目的探究卡马西平与左乙拉西坦治疗成人癫痫的效果及对认知功能、骨密度的影响。方法92例成人癫痫患者作为研究对象,随机分为左乙拉西坦组与卡马西平组,各46例。左乙拉西坦组采用左乙拉西坦治疗,卡马西平组采用卡马西平治疗。比较两组患者治疗前及治疗6个月后认知功能[语言智商(VIQ)、操作智商(PIQ)、总智商(FIQ)]评分、骨密度(腰椎、股骨大转子、股骨颈)变化情况。结果治疗6个月后,两组患者VIQ、PIQ、FIQ评分均较治疗前显著提升,且左乙拉西坦组患者VIQ评分(101.2±3.1)分、PIQ评分(108.1±2.3)分、FIQ评分(105.2±1.8)分均明显高于卡马西平组的(95.1±2.8)、(94.1±2.0)、(93.5±1.6)分,差异有统计学意义(P<0.05)。治疗6个月后,卡马西平组患者腰椎、股骨大转子、股骨颈骨密度均较治疗前显著下降,且明显低于卡马西平组,差异有统计学意义(P<0.05);左乙拉西坦组治疗6个月后腰椎、股骨大转子、股骨颈骨密度与治疗前比较差异无统计学意义(P>0.05)。结论左乙拉西坦与卡马西平治疗成人癫痫,左乙拉西坦更能明显提升患者认知功能,且对患者骨密度无影响。  相似文献   
80.
目的:探讨痰热内蕴型哮喘婴幼儿西医常规治疗基础上使用自拟热咳散治疗的临床疗效,为其临床应用提供理论依据。方法:选取2017年3月至2018年9月中山市中医院收治的痰热内蕴型哮喘婴幼儿112例作为研究对象,根据治疗方式的不同分为对照组与观察组,每组56例。对照组采用常规治疗,观察组在对照组基础上加用自配热咳散,比较2组患儿肺功能指标(FEF25%、FEF50%、IgE);血清生化指标(IL-6、TNF-α、CRP、Cal-3)和C-ACT和MARS-A评分的差异。结果:对照组FEF25%、FEF50%显著低于观察组,对照组IgE含量显著高于观察组,差异均有统计学意义(P<0.05)。2组患儿治疗有效率和治疗效果构成差异有统计学意义(P<0.05)。治疗后观察组IL-6、TNF-α、CRP、Cal-3含量低于对照组,观察组C-ACT评分、MARS-A评分高于对照组,差异均有统计学意义(P<0.05)。结论:相比于西医常规治疗的治疗手段,在其基础上连用自拟热咳散的治疗效果更佳,患者症状改善时间也相对较短。  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