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   943篇
  免费   189篇
  国内免费   45篇
  1177篇
  2024年   16篇
  2023年   52篇
  2022年   72篇
  2021年   62篇
  2020年   39篇
  2019年   48篇
  2018年   38篇
  2017年   44篇
  2016年   33篇
  2015年   52篇
  2014年   54篇
  2013年   84篇
  2012年   38篇
  2011年   44篇
  2010年   28篇
  2009年   36篇
  2008年   36篇
  2007年   25篇
  2006年   33篇
  2005年   24篇
  2004年   25篇
  2003年   22篇
  2002年   13篇
  2001年   19篇
  2000年   13篇
  1999年   20篇
  1998年   17篇
  1997年   17篇
  1996年   7篇
  1995年   13篇
  1994年   16篇
  1993年   15篇
  1992年   25篇
  1991年   15篇
  1990年   11篇
  1989年   14篇
  1988年   9篇
  1987年   9篇
  1986年   7篇
  1985年   3篇
  1984年   5篇
  1982年   6篇
  1981年   3篇
  1980年   4篇
  1978年   4篇
  1977年   1篇
  1976年   2篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
排序方式: 共有1177条查询结果,搜索用时 15 毫秒
41.
摘要 目的:研究基于加速康复外科(ERAS)理念的早期康复训练联合八段锦前四式在乳腺癌改良根治术后患者中的应用效果。方法:选择2019年9月~2022年5月期间在湖南中医药大学第一附属医院行乳腺癌改良根治术的128例乳腺癌患者。按照随机数字表法将患者分为对照组(基于ERAS理念的早期康复训练,n=64)和研究组(对照组的基础上接受八段锦前四式干预,n=64)。对比两组抑郁自评量表(SDS)评分、健康调查简表(SF-36)、焦虑自评量表(SAS)评分、Constant-Murley肩关节功能评分、疼痛视觉模拟评分(VAS)和肩关节活动度。结果:与对照组相比,研究组干预后SDS、SAS评分更低(P<0.05)。与对照组相比,研究组情感/生理职能、躯体疼痛、社会/生理功能、活力、总体/精神健康评分更高(P<0.05)。与对照组相比,研究组干预后VAS评分更低,Constant-Murley肩关节功能评分更高(P<0.05)。与对照组相比,研究组干预后前屈、后伸、外展关节活动度更大(P<0.05)。结论:基于ERAS的早期康复训练联合八段锦前四式应用于乳腺癌改良根治术后患者,可提高患者的生活质量,可能与缓解焦虑、抑郁情绪,减轻术后疼痛,促进肩关节功能恢复有关。  相似文献   
42.
Spiders can use air particle movements to localize moving prey. We studied the responses of 32 wind-sensitive interneurones in the hunting spider Cupiennius salei to prey stimuli. Stimulation with a tethered flying fly or with artificial air pulses activated plurisegmental interneurones that responded to changes in air movement velocity and were thus well suited to represent the highly fluctuating air stream typical of prey stimuli. In most interneurones (n = 18) the responses to the stimulation of different legs were not significantly different from each other. Different interneurones had different response characteristics and their latencies largely overlapped suggesting that there is parallel processing of the signals by populations of interneurones with different response characteristics. In two interneurones the number of spikes and the spiking pattern elicited by stimulation of each of the eight legs markedly differed depending on the leg stimulated. These neurones may play an important role in directional information processing. Stimulation of the adjacent legs from front to back or from back to front revealed two interneurones sensitive to the direction of successive stimulation of the legs. These neurones may be able to detect the motion of an air movement source in a preferred direction and thus act as nearfield motion detectors to localize a moving prey item. Accepted: 28 September 1996  相似文献   
43.
The effect of an endurance training program lasting 17 weeks was studied in two cyprinid species, Chondrostoma nasus (L.) and Leuciscus cephalus (L.). Red, intermediate and white axial muscle were investigated. Morphometrical analysis revealed that training induced, in both species, increased red and intermediate muscle mass, fibre diameter and capillarization. Differences between species in the response to training were observed for volume densities of mitochondria and lipid. In contrast to C. nasus, L. cephalus show higher values for these compartments in red and intermediate fibres. The results are considered adaptational changes which increase the aerobic capacity of red and intermediate muscle fibres to meet higher sustained swimming activities.  相似文献   
44.
45.
目的: 探讨个体化精准运动为核心的整体康复方案对冠心病介入治疗术后患者整体功能再提高的作用。方法: 选择2016 年6 月至2019 年12 月间在北京康复医院临床诊断为冠心病稳定性心绞痛患者20 例,随机分为对照组(n=10)和运动组(n=10)。全部患者择期行冠状动脉介入治疗,术后对照组患者仅进行除运动康复之外的常规治疗指导;运动组患者进行12周个体化运动为核心的心脏康复,介入前、介入后2周、康复后12周分别评估患者标准化症状限制性极限运动的心肺运动试验(CPET)指标、心脏超声、6 min步行距离(6MWD)等。结果: 所有患者均安全无并发症完成症状限制性CPET,运动组患者完成12周全程运动康复治疗。组间比较显示,介入前和介入后2周,对照组和运动组患者CPET指标以及左心室射血分数、6MWD等均无明显差异(P>0.05)。康复12周后,运动组患者无氧阈(ml/min、ml/(min·kg))、峰值摄氧量(ml/(min·kg))、氧脉搏(ml/beat)和6MWD较对照组明显升高,差异有统计学意义(P<0.05)。组内比较显示,康复治疗12周后,运动组患者无氧阈(ml/min、ml/(min·kg)、%pred)、峰值摄氧量(ml/min、ml/(min·kg)、%pred)、峰值氧脉搏(ml/beat)和6MWD均较介入前明显改善,差异有统计学意义(P<0.05);而且与介入后2周比较,无氧阈(ml/(min·kg))和峰值摄氧量(ml/(min·kg))均明显升高,差异有统计学意义(P<0.05)。对照组患者在康复12周后无氧阈(ml/min)和峰值氧脉搏(ml/beat)较介入前改善,差异有统计学意义(P<0.05),但CPET指标与介入后2周比较无明显差异。结论: 冠状动脉介入术后进行个体化运动康复为核心的整体管理可进一步提高冠心病稳定性心绞痛患者运动心肺功能和运动耐力。运动康复是介入术后患者二级预防的重要内容,需要大量推广。  相似文献   
46.
目的: 探讨间歇速度训练和耐力训练对大鼠骨骼肌纤维类型转化及钙调蛋白激酶/肌细胞增强因子2(CaMK II/MEF2)信号传导通路的影响。方法: 成年雄性SD大鼠(8周龄)18只,随机分成间歇速度训练组(IST),耐力训练组(ET),设空白组(C),每组6只,IST组采用75 m/min×1 min、20 m/min×1 min的交替训练6次,跑台坡度15,持续时间12 min/d;ET组采用速度30 m/ min、跑台坡度7、持续时间90 min/d的耐力训练。干预8周后,分别取小鼠右侧胫骨前肌、比目鱼肌,酶联免疫吸附法检测骨骼肌琥珀酸脱氢酶(SDH)、乳酸脱氢酶(LDH)活性,ATP酶染色法观察I、Ⅱ型肌纤维面密度、数密度变化情况,SDS-PAGE凝胶电泳技术观察骨骼肌MHC亚型百分比含量、骨骼肌mRNA表达谱测序分析及qRT-PCR技术检测CaN、CaMKII、MEF2水平。结果: 相比C组,ET组SDH活性显著上升,LDH活性降低(P<0.05);IST组胫骨前肌中LDH活性值升高(P<0.01)。ET组胫骨前肌MHCIIa%升高,MHCIIb%降低(P<0.05),比目鱼肌MHCI% 和MHCIIa%升高,MHCIIb%均降低(P<0.05)。相比IST组,ET组胫骨前肌MHCIIx%升高(P<0.05)。相比C组,ET组胫骨前肌 I、II 型纤维纤维密度上升,IST组II型纤维纤维密度提高,IST组、ET组比目鱼肌I型纤维纤维密度上升(P<0.05)。相比C组,ET组骨骼肌CaN、CaMKII、MEF2 mRNA表达水平增高,IST组CaN、CaMKII、MEF2 mRNA表达水平下降(P<0.01)。Illumina高通量测序筛选骨骼肌纤维转化相关因子及关联分析,运动干预促使骨骼肌纤维转化相关因子表达变化富集于TGF-β/Smad3、CaN/MEF2、AdipoQ等信号通路,而耐力训练显著提高骨骼肌纤维转化、干细胞功能相关信号通路的富集。结论: 耐力训练促进向氧化型肌纤维转化(慢肌),而间歇速度训练向酵解型肌纤维转化(快肌),并伴随着CaMK II/MEF2传导途径中CaN、CaMKII、MEF2基因的高表达。  相似文献   
47.
Directional modifications of resibufogenin 1 by Mucor subtilissimus and Pseudomonas aeruginosa were carried out. The substrate was hydroxylated at C-12 by M. subtilissimus AS 3.2454, from which a major product 12-hydroxyresibufogenin 2 was obtained. Then product 2 was dehydrogenated by P. aeruginosa AS 1.860, which resulted in a new compound 12β-hydroxy-3-keto-resibufogenin 3.  相似文献   
48.
Exercise training has demonstrated cardioprotection effects. However, the exact mechanism behind this effect is not is clear. The present study evaluated the effects of 12 weeks of previous treadmill training on the levels of oxidative damage, antioxidant enzyme activity and injury in the myocardium of rats submitted to infarction induced by isoproterenol (ISO). Isoproterenol treatment (80 mg/kg given over 2 days in two equal doses) caused arrhythmias and 60% mortality within 24 h of the last injection in the control group (C + ISO) group when compared with the saline control group (saline). Creatine Kinase ? MB levels were markedly increased in hearts from ISO-treated animals in the C + ISO group. Twelve weeks of treadmill training reduced superoxide production, lipid peroxidation levels and protein carbonylation in these animals, as well as increasing the activities and expressions of SOD and CAT. Previous training also reduced CK-MB levels and numbers of deaths by 40%, preventing the deleterious effects of ISO. Based on the data obtained in this study, it is suggested that 12-week treadmill training increases antioxidant enzymes, decreases oxidative damage and reduces the degree of infarction induced by ISO in the hearts of male rats.  相似文献   
49.
To clarify changes of neutrophil functions, mental conditions and relationships among them, 19 male elite long‐distance runners participated in this study for 6 months. Examinations, with informed consent, were carried out once a month. According to the results of physical characteristics, it was thought that training intensity was reduced after the main race, Hakone‐Ekiden. Neutrophil functions were estimated by indices of reactive oxygen species production, determined by luminol‐ and lucigenin‐dependent chemiluminescence (LmCL and LgCL, respectively) and cytochrome c reduction methods. The peak times (PT) in LmCL and LgCL (LgPT) were most prolonged in January and December, respectively. The peak heights (PH) in LmCL (LmPH) were enhanced in February. Decreased levels of negative categories in the profile of mood state (POMS) questionnaire and the total mood state (TMS) of POMS were observed in February without significance. Correlation analysis using measured values revealed significant negative correlation between LmPH and negative categories in POMS; however, these correlations were possibly a mere appearance, caused by personal differences. After eliminating personal differences, LgPT correlated positively to depression (p < 0.05), anger (p < 0.05), fatigue (p < 0.01) and TMS (p < 0.05). These results suggest that the mean time from the recognition of foreign matter to the maximum production of superoxide from neutrophils is prolonged in the mentally suppressed conditions found under continuous physical training. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
50.
Bilateral symmetry is widespread in animal kingdom, however most animal can deviate from expected symmetry and manifest some kind of asymmetries. Fluctuating asymmetry is considered as a tool for valuating developmental instability, whereas directional asymmetry is inherited and could be used for evaluating evolutionary development. We use the method of geometric morphometrics to analyze left/right asymmetries in the whole body, in two sites and totally six populations of Ceroglossus chilensis with the aim to infer and explain morphological disparities between populations and sexes in this species. In all individuals analyzed we found both fluctuating asymmetry and directional asymmetry for size and shape variation components, and a high sexual dimorphism. Moreover a high morphological variability between the two sites emerged as well. Differences in diet could influence the expression of morphological variation and simultaneously affect body sides, and therefore contribute to the symmetric component of variation. Moreover differences emerged between two sites could be a consequence of isolation and fragmentation, rather than a response to local environmental differences between sampling sites.  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