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   83451篇
  免费   7859篇
  国内免费   2437篇
耳鼻咽喉   855篇
儿科学   2032篇
妇产科学   729篇
基础医学   6552篇
口腔科学   1630篇
临床医学   12818篇
内科学   13442篇
皮肤病学   585篇
神经病学   6591篇
特种医学   3321篇
外国民族医学   4篇
外科学   9133篇
综合类   14700篇
现状与发展   3篇
预防医学   5680篇
眼科学   1156篇
药学   7565篇
  115篇
中国医学   4991篇
肿瘤学   1845篇
  2024年   352篇
  2023年   1452篇
  2022年   3010篇
  2021年   4259篇
  2020年   4096篇
  2019年   3282篇
  2018年   3066篇
  2017年   3430篇
  2016年   3439篇
  2015年   3032篇
  2014年   5785篇
  2013年   5828篇
  2012年   4710篇
  2011年   4998篇
  2010年   4066篇
  2009年   3784篇
  2008年   3897篇
  2007年   4019篇
  2006年   3569篇
  2005年   3018篇
  2004年   2491篇
  2003年   2152篇
  2002年   1861篇
  2001年   1709篇
  2000年   1419篇
  1999年   1222篇
  1998年   1021篇
  1997年   962篇
  1996年   834篇
  1995年   847篇
  1994年   735篇
  1993年   581篇
  1992年   630篇
  1991年   506篇
  1990年   437篇
  1989年   374篇
  1988年   360篇
  1987年   346篇
  1986年   286篇
  1985年   313篇
  1984年   319篇
  1983年   190篇
  1982年   231篇
  1981年   157篇
  1980年   140篇
  1979年   124篇
  1978年   128篇
  1977年   68篇
  1976年   65篇
  1975年   42篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.

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   
63.
Context: We sought to describe our experience with the Hybrid Assistive Limb® (HAL®) for active knee extension and voluntary ambulation with remaining muscle activity in a patient with complete paraplegia after spinal cord injury.

Findings: A 30-year-old man with complete paraplegia used the HAL® for 1 month (10 sessions) using his remaining muscle activity, including hip flexor and upper limb activity. Electromyography was used to evaluate muscle activity of the gluteus maximus, tensor fascia lata, quadriceps femoris, and hamstring muscles in synchronization with the Vicon motion capture system. A HAL® session included a knee extension session with the hip flexor and voluntary gait with upper limb activity. After using the HAL® for one month, the patient’s manual muscle hip flexor scores improved from 1/5 to 2/5 for the right and from 2/5 to 3/5 for the left knee, and from 0/5 to 1/5 for the extension of both knees.

Conclusion/clinical relevance: Knee extension sessions with HAL®, and hip flexor and upper-limb-triggered HAL® ambulation seem a safe and feasible option in a patient with complete paraplegia due to spinal cord injury.  相似文献   

64.
目的 采用网络药理学阐明济脉通片多成分-多靶点-多途径的作用理念,为进一步研究济脉通片降压药效物质基础和机制提供一定理论参考。方法 通过TCMSP数据库,结合口服利用度(≥ 30%)和类药性分析(≥ 0.18)参数,筛选济脉通片的活性成分;通过Drugbank和TCMSP数据库进行靶点预测分析;通过GENCARD数据库筛选出高血压疾病相关基因;结合DAVID和KEGG数据库进行GO分析和通路分析;使用Cystoscope软件构建"化合物-靶点-作用通路"网络图。结果 经筛选后得到济脉通片的33个化合物,148个潜在靶基因并映射到了223条信号通路,其中31条信号通路与高血压的发生发展密切相关,其中AGE-RAGE signaling pathway in diabetic complications、PI3K-Akt signaling pathway、TNFsignaling pathway、Adrenergic signaling in cardiomyocytes和Focal adhesion为重要的通路枢纽。结论 济脉通片主要通过多成分、多靶点、多通路调节血管内皮功能、炎症反应、钙钠离子转运、糖脂代谢等参与血管舒张、改善炎症、调节机体代谢、调节离子转运等而产生降压作用。  相似文献   
65.
Fetal activity parameters such as movements, heart rate and the related parameters are essential indicators of fetal wellbeing, and no device provides simultaneous access to and sufficient estimation of all of these parameters to evaluate fetal health. This work was aimed at collecting these parameters to automatically separate healthy from compromised fetuses. To achieve this goal, we first developed a multi-sensor–multi-gate Doppler system. Then we recorded multidimensional Doppler signals and estimated the fetal activity parameters via dedicated signal processing techniques. Finally, we combined these parameters into four sets of parameters (or four hyper-parameters) to determine the set of parameters that is able to separate healthy from other fetuses. To validate our system, a data set consisting of two groups of fetal signals (normal and compromised) was established and provided by physicians. From the estimated parameters, an instantaneous Manning-like score, referred to as the ultrasonic score, was calculated and was used together with movements, heart rate and the associated parameters in a classification process employing the support vector machine method. We investigated the influence of the sets of parameters and evaluated the performance of the support vector machine using the computation of sensibility, specificity, percentage of support vectors and total classification error. The sensitivity of the four sets ranged from 79% to 100%. Specificity was 100% for all sets. The total classification error ranged from 0% to 20%. The percentage of support vectors ranged from 33% to 49%. Overall, the best results were obtained with the set of parameters consisting of fetal movement, short-term variability, long-term variability, deceleration and ultrasound score. The sensitivity, specificity, percentage of support vectors and total classification error of this set were respectively 100%, 100%, 35% and 0%. This indicated our ability to separate the data into two sets (normal fetuses and pathologic fetuses), and the results highlight the excellent match with the clinical classification performed by the physicians. This work indicates the feasibility of detecting compromised fetuses and also represents an interesting method of close fetal monitoring during the entire pregnancy.  相似文献   
66.
67.
《中国现代医生》2020,58(2):135-138+封三
目的探讨实时剪切波弹性成像在评估拉米夫定治疗乙肝纤维化临床疗效中的作用。方法选取2017年1月~2018年1月我院收治的80例乙肝纤维化患者,根据随机数字法分为对照组和观察组,每组40例。对照组采用常规治疗,观察组在对照组的基础上给予拉米夫定进行治疗,治疗6个月。比较两组治疗前后肝功能、肝纤维化指标,利用实时剪切波弹性成像评估两组治疗前后肝脏弹性模量值及肝穿刺活检情况,并进行比较。结果两组治疗后AST、ALT、TBIL水平均明显低于治疗前,差异有统计学意义(P0.05);观察组治疗后AST、ALT、TBIL水平均明显低于对照组,差异有统计学意义(P0.05);两组治疗后HA、LN、PⅢPN-P、CL-Ⅳ水平及杨氏弹性模量值均显著低于治疗前,差异有统计学意义(P0.05);观察组治疗后HA、LN、PⅢPN-P、CL-Ⅳ水平及杨氏弹性模量值均显著低于对照组,差异有统计学意义(P0.05);与治疗前相比,两组治疗后肝穿刺活检结果均有好转,尤其是汇管区、肝小叶内炎症及肝纤维化改善明显。结论实时剪切波弹性成像作为肝脏硬度定量检测的无创性技术,可用于拉米夫定治疗乙肝纤维化临床疗效评估的重要方法。  相似文献   
68.
《Journal of hand therapy》2020,33(4):528-539
Study DesignProspective longitudinal cohort study.IntroductionTraumatic brachial plexus injuries (BPIs) can be devastating and negatively impact daily function and quality of life. Occupational therapists play an important role in rehabilitation; however, studies identifying outcomes are lacking.PurposeThis study aims to describe outcomes including motor recovery, upper limb function, participation, pain, and quality of life for people receiving occupational therapy intervention.MethodsA convenience sample of English-speaking adults (n = 30) with a traumatic BPI, attending the clinic between December 1, 2014, to November 30, 2016, participated. Participants received occupational therapy focusing on sensorimotor retraining and activity-based rehabilitation. Data on active range of motion (goniometry), strength (Medical Research Council (MRC)), upper-limb function (UEFI15, QuickDASH), participation (PSFS), pain (Brief Pain Inventory), and quality of life (EQ-5D-3L) were collected at baseline, 3, 6, 9, and 12 months.ResultsElbow flexion strength showed significant improvement at all time-points, average increase 2.17 (MRC) (95% confidence interval: 1.29-3.04; P < .001) and mean final MRC grading 3.86 (standard error: 0.44). Significant improvements at 12 months were seen in: shoulder abduction strength and range, flexion strength and range, external rotation range; elbow extension strength and flexion range; thumb flexion and extension strength. Upper limb function (QuickDASH) showed significant improvement (mean change = 18.85; 95% confidence interval: 4.12-33.59; P = .02). Forearm protonation range and finger flexion strength were significantly worse. Remaining outcomes did not show significant improvement.ConclusionsOccupational therapy with surgical intervention can improve strength, range, and upper limb function with people following traumatic BPI. Further investigations into impact on participation, pain, and quality of life are required.  相似文献   
69.
Algorithms based on deep neural networks (DNNs) have attracted increasing attention from the scientific computing community. DNN based algorithms are easy to implement, natural for nonlinear problems, and have shown great potential to overcome the curse of dimensionality. In this work, we utilize the multi-scale DNN-based algorithm (MscaleDNN) proposed by Liu, Cai and Xu (2020) to solve multi-scale elliptic problems with possible nonlinearity, for example, the p-Laplacian problem. We improve the MscaleDNN algorithm by a smooth and localized activation function. Several numerical examples of multi-scale elliptic problems with separable or non-separable scales in low-dimensional and high-dimensional Euclidean spaces are used to demonstrate the effectiveness and accuracy of the MscaleDNN numerical scheme.  相似文献   
70.
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