全文获取类型
收费全文 | 7373篇 |
免费 | 180篇 |
国内免费 | 203篇 |
专业分类
教育 | 2117篇 |
科学研究 | 356篇 |
各国文化 | 16篇 |
体育 | 3838篇 |
综合类 | 1397篇 |
信息传播 | 32篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 47篇 |
2021年 | 119篇 |
2020年 | 153篇 |
2019年 | 118篇 |
2018年 | 155篇 |
2017年 | 155篇 |
2016年 | 173篇 |
2015年 | 187篇 |
2014年 | 340篇 |
2013年 | 702篇 |
2012年 | 471篇 |
2011年 | 524篇 |
2010年 | 366篇 |
2009年 | 353篇 |
2008年 | 405篇 |
2007年 | 548篇 |
2006年 | 484篇 |
2005年 | 450篇 |
2004年 | 426篇 |
2003年 | 350篇 |
2002年 | 302篇 |
2001年 | 261篇 |
2000年 | 215篇 |
1999年 | 118篇 |
1998年 | 80篇 |
1997年 | 75篇 |
1996年 | 45篇 |
1995年 | 38篇 |
1994年 | 24篇 |
1993年 | 30篇 |
1992年 | 19篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有7756条查询结果,搜索用时 17 毫秒
1.
2.
田径运动是所有运动的基础运动,是促进身体健康的重要手段,对实现健康中国战略有重要的意义。本研究以普通高校大学体育田径运动的教学及发展路径为切入点,对几所高校进行调查分析,找出田径运动发展过程中存在的问题,并提出相关建议,使田径运动在高校更好地发展,促进健康中国战略目标的贯彻实施。 相似文献
3.
利用UAS/hand-gal4系统构建果蝇心脏Nmnat基因特异性过表达,研究心脏Nmnat基因过表达联合耐力运动对高脂膳食诱发脂毒性心肌症的影响,并分析其分子机制。方法:雄性w^1118和NmnatUAS系果蝇分别与雌性hand-Gal4杂交,收集F1代心脏Nmnat正常表达(hand>w^1118)和过表达(hand>Nmnat)处女蝇,饲养至15 d后开始进行耐力运动(E)和高脂膳食(HFD),并分为hand>w^1118、hand>w^1118+E、hand>w^1118+HFD、hand>w^1118+HFD+E、hand>Nmnat、hand>Nmnat+E、hand>Nmnat+HFD、hand>Nmnat+HFD+E共8组,每组410只。ELISA检测心脏TAG、NAD+、SIR2蛋白去乙酰化、SOD活力和MDA水平,qRT-PCR检测心脏相关基因mRNA表达,M-mode检测心脏功能情况。结果:hand>w^1118+HFD+E果蝇心脏的Nmnat、dFoxo、bmm表达、NAD+水平、SIR2去乙酰化、SOD活力、缩短分数高于hand>w^1118+HFD(P<0.05或P<0.01),且d FAS和Col4al表达、TAG和MDA水平、心率和纤维性振颤低于hand>w^1118+HFD(P<0.05或P<0.01);hand>Nmnat果蝇心脏各指标与hand>Nmnat+HFD相比较未见显著差异(P>0.05);hand>Nmnat+HFD+E果蝇心脏的Nmnat、dFoxo、bmm表达、心脏NAD+水平、SIR2去乙酰化、SOD活力、心脏缩短分数高于hand>Nmnat+HFD(P<0.05或P<0.01),且dFAS和Col4al表达\TAG和MDA水平、心率和纤维性振颤低于hand>Nmnat+HFD(P<0.05或P<0.01)。结论:心脏Nmnat过表达和耐力运动均能抵抗果蝇高脂膳食诱发的心脏脂质过度堆积、氧化损伤、减弱心脏收缩能力和增加纤维性振颤,其分子机制与心脏Nmnat/NAD+/SIR2/dFoxo通路活性增强有关。心脏Nmnat基因过表达联合耐力运动能更好地降低脂毒性心肌症的发生概率,其机制与二者联合对心脏Nmnat/NAD+/SIR2/dFoxo通路活性上调的叠加作用有关。 相似文献
4.
目的:探讨不同负荷运动训练对大鼠骨骼肌线粒体三羧酸循环的影响及其机制。方法:将雄性Wistar大鼠50只随机均分为5组:安静对照组(C)、低负荷运动训练组(LT)、中等负荷运动训练组(MT)、高负荷运动训练组(HT)和极高负荷运动训练组(ST),每组10只。各运动组分别进行6周的跑台运动训练。训练方案结束后,取腓肠肌样本,提取线粒体,测定线粒体柠檬酸合成酶(CS)、异柠檬酸脱氢酶(ICD)和α-酮戊二酸脱氢酶(α-KGDHC)活性;线粒体Ga2+含量、胞浆NADH、NAD+、ATP和ADP含量,以及ICD mRNA转录水平。结果:(1)不同负荷运动训练组线粒体CS、ICD和α-KGDHC的活性均显著高于安静对照组(P < 0.01),且CS和ICD活性由高到低顺序均为:MT组 > HT组 > ST组 > LT组 > C组,α-KGDHC活性由高到低顺序为:HT组 > MT组 > ST组 > LT组 > C组。(2)不同负荷运动训练组线粒体Ca2+ 含量均显著高于安静对照组(P < 0.01),其含量由高到低顺序为:MT组 > HT组 > ST组 > LT组 > C组;胞浆NADH/NAD+和ATP/ADP的比值均显著低于安静对照组(P < 0.01),其比值由低到高顺序为:MT组 < ST组 < HT组 < LT组 < C组。(3)不同负荷运动训练组ICD mRNA转录水平均高于安静对照组(P < 0.01),其水平由高到低顺序为: MT组 > HT组 > ST组 > LT组 > C组。结论:低负荷、中等负荷、高负荷及极高负荷运动训练均可提高大鼠骨骼肌线粒体三羧酸循环功能,且中等负荷运动训练效果最佳。其机制与胞浆NADH/NAD+和ATP/ADP比值、线粒体摄钙能力及限速酶基因的表达有关。 相似文献
5.
Understanding how social worker compassion fatigue and years of experience shape custodial decisions
BackgroundCompassion fatigue (i.e., a worker’s diminished ability to empathize with clients) is common among “helping workers” and can result in psychological detachment from clients as a coping mechanism.ObjectiveIn the present research, we explored the relationship between social workers’ compassion fatigue and years of job experience on hypothetical child custody case judgments.Participants and settingIn two separate studies, individuals with experience working with children in child dependency court (predominantly social workers, Study 1: N = 173, Study 2: N = 119) were recruited on Amazon’s Mechanical Turk and read a vignette depicting a mother attempting to regain custody.ResultsSupporting hypotheses, compassion fatigue significantly mediated the relationship between increased years of social worker job experience on recommendations that a neglectful mother receive custody, Indirect Effect = .06, CIs [.026, .127] (Study 1). We also found preliminary support for our hypothesized theoretically derived serial path model, in which (a) social worker compassion fatigue predicts anticipated secondary traumatic stress associated with the child neglect case, B = .54, p = .0001; (b) secondary traumatic stress predicts detachment from the neglected child, B = .27, p = .0003; (c) detachment from the child predicts job efficacy cynicism B = .65, p < .0001; and (d) job efficacy cynicism predicts decisions to allocate custody to the neglectful mother, B = .46, p = .005 (Study 2).ConclusionOur research shows that compassion fatigue among social workers may change the lens through which they perceive cases of child abuse. 相似文献
6.
Yoann M. Garnier Christos Paizis Romuald Lepers 《European Journal of Sport Science》2019,19(2):166-176
The present study assessed neuromuscular and corticospinal changes during and after a fatiguing submaximal exercise of the knee extensors in different modes of muscle contraction. Twelve subjects performed two knee extensors exercises in a concentric or eccentric mode, at the same torque and with a similar total impulse. Exercises consisted of 10 sets of 10 repetitions at an intensity of 80% of the maximal voluntary isometric contraction torque (MVIC). MVIC, maximal voluntary activation level (VAL) and responses of electrically evoked contractions of the knee extensors were assessed before and after exercise. Motor evoked potential amplitude (MEP) and cortical silent period (CSP) of the vastus medialis (VM) and rectus femoris (RF) muscles were assessed before, during and after exercise. Similar reductions of the MVIC (?13%), VAL (?12%) and a decrease in the peak twitch (?12%) were observed after both exercises. For both VM and RF muscles, MEP amplitude remained unchanged during either concentric or eccentric exercises. No change of the MEP amplitude input–output curves was observed post-exercise. For the RF muscle, CSP increased during the concentric exercise and remained lengthened after this exercise. For the VM muscle, CSP was reduced after the eccentric exercise only. For a similar amount of total impulse, concentric and eccentric knee extensor contractions led to similar exercise-induced neuromuscular response changes. For the two muscles investigated, no modulation of corticospinal excitability was observed during or after either concentric or eccentric exercises. However, intracortical inhibition showed significant modulations during and after exercise. 相似文献
7.
目的:锻炼与针刺组合对退行性膝关节炎微循环血流灌注量的影响。方法:研究对象40例随机分为2组,分别是针刺组(单纯针刺)和锻炼组(站桩与针刺组合),对其实验前后疼痛程度(VAS)、微循环血流灌注量(MBPU)及皮肤温度的变化进行检测分析。结果:两组实验后,VAS评分明显降低(P<0.01),锻炼组优于针刺组(P<0.05);MBPU降低(P<0.01),锻炼组优于针刺组(P<0.05);局部温度明显提高(P<0.05)。结论:锻炼与针刺组合可以明显缓解退行性膝关节炎的疼痛症状,降低局部微循环血流灌注量,提高皮肤温度;优于单纯针刺疗法。 相似文献
8.
In social networking services (SNSs), users’ unclear understanding of the large and invisible audience increases the chances of online turbulence, which is a key source of SNS-induced stress. This growing phenomenon has gained increasing attention in academia and industry due to the undesirable consequences for users and SNS platforms. In this study, we draw from the transactional model of stress to examine how audience management strategies impact online turbulence and lead to neglected unintended audience concern and lurking. We also investigate the role of self-monitoring as a stress inhibitor. We test our model with data collected from 301 SNS users. The results show that the four types of audience management strategies have different effects on online turbulence, which significantly impacts neglected unintended audience concern especially when users have high self-monitoring skills. We believe that this work contributes, both from scientific and practical standpoints, to the understanding of the interventions and stressful responses of online turbulence in SNSs. 相似文献
9.
Jennifer L. Etnier Paul M. Sprick Jeffrey D. Labban Chia-Hao Shih Stephen M. Glass Jarod C. Vance 《Journal of sports sciences》2020,38(19):2264-2272
ABSTRACT Meta-analytic evidence supports that exercise has benefits for short-term memory (STM) and long-term memory (LTM). However, only three studies with children have tested the differential effects of exercise on STM and LTM. The purpose of this study was to examine the effects of an aerobic fitness test on STM and LTM and to consider the moderating effects of grade level. Children (7–13 years of age) were randomly assigned to either perform an aerobic fitness test before (exercise prior) or after (exercise post) performing the Rey Auditory Verbal Learning Test (RAVLT) to assess memory. Memory was tested again after approximately 24 hours. There were significant differences in memory performance as a function of grade with 4th and 6th graders consistently outperforming 2nd graders. For learning, Day 1 Retention, 24-hr recall, and Day 2 Retention, the exercise prior group performed better than the exercise post group. It is concluded that an aerobic fitness test performed prior to a declarative memory test benefits LTM as compared to when the aerobic fitness test is performed after the memory test. 相似文献
10.
We test acculturative stress, Hybrid (HIS) and Alternating (AIS) Identity Styles, and their interaction effects as predictors of psychosocial functioning over a 12-day period among Hispanic American university students. Participants completed measures of acculturative stress, HIS, AIS, and internalizing (anxiety and depression) and externalizing (social aggression and rule-breaking) symptoms on Day 1; on Day 12 they completed the symptom measures a second time. Structural equation modelling was used to examine the Day 1 effects of acculturative stress, cultural identity styles, and their interactions on Day 12 symptoms controlling for the Day 1 symptoms. We hypothesized that acculturative stress would predict more, and the HIS would predict fewer, symptoms and that the AIS would moderate the relationship between acculturative stress and symptoms over time. Results indicated that: (1) acculturative stress predicted an increase in internalizing symptoms; (2) the HIS predicted a decrease in internalizing and externalizing symptoms; and (3) the AIS attenuated the relationship between acculturative stress and externalizing symptoms. The results are discussed in relation to the distinctive features of internalizing and externalizing symptoms, and recommendations for future research are advanced. 相似文献