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   267篇
  免费   6篇
  2024年   1篇
  2023年   1篇
  2022年   1篇
  2021年   2篇
  2020年   1篇
  2019年   3篇
  2017年   2篇
  2016年   5篇
  2015年   2篇
  2014年   10篇
  2013年   9篇
  2012年   27篇
  2011年   35篇
  2010年   19篇
  2009年   8篇
  2008年   24篇
  2007年   31篇
  2006年   25篇
  2005年   23篇
  2004年   10篇
  2003年   16篇
  2002年   6篇
  2001年   2篇
  2000年   3篇
  1999年   1篇
  1995年   2篇
  1993年   1篇
  1989年   2篇
  1982年   1篇
排序方式: 共有273条查询结果,搜索用时 187 毫秒
11.
Is agility related to strength qualities?--Analysis in latent space   总被引:1,自引:0,他引:1  
In this study we examined an influence of leg extensor strength qualities on agility performance in a latent space. Male physical education students (N = 168) were tested with three standard agility performance tests (lateral stepping, 20-yard shuttle run, and slalom run). Nine measures of leg extensor strength qualities including explosive strength, elastic strength, and maximal strength, were also assessed. As expected, factor analysis of all tests revealed four relatively independent factors: explosive strength, elastic strength, agility, and maximal strength. All three extracted strength factors were included into a regression analysis as predictors to evaluate their influence of the agility factor (i.e. criterion). Although the regression analysis revealed significant multiple correlation between predictors and the criterion (R = 0.41; p < 0.001), the amount of explained variance of agility performance by the strength factors was rather low (17%). We conclude that the leg extensor strength qualities are poor predictors of agility performance in physically active men.  相似文献   
12.
Preemptive analgesia refers to blockade of afferent nerve fibers before a painful stimulus, which prevents or reduces subsequent pain even beyond the effect of the block. The aim of the study was to compare the effect of clonidine used before and at the end of operation on pain control in abdominal surgery. A total of 77 patients admitted for colorectal surgery were randomly classified into three groups: epidural clonidine before operation, epidural clonidine at the end of operation, and control group. After the operation on patient demand, analgesia with boluses of epidural morphine was instituted. The parameters of postoperative pain level using VAS score (visual analog scale), sedation and analgesics consumption were determined as outcome measures at 1, 2, 6, and 24 h of the operation. Clonidine administered before operation provided lowest pain scores at 6 and 24 h (p < 0.05). Clonidine administered at the end of operation had low pain scores at 1 and 2 h, with a significant pain breakthrough thereafter (6.93 +/- 1.66 at 6 h and 4.04 +/- 2.39 at 24 h) compared with the group administered clonidine before operation (3.60 +/- 2.94 and 3.71 +/- 1.82). Clonidine administered before operation provided less sedation (p < 0.05) and a significantly lower use of analgesics (p < 0.05). Blockade of nociceptive stimulus using the centrally acting alpha2-adrenergic agonist clonidine before the onset of pain stimulus resulted in reduced pain levels, sedation and analgesic requirement.  相似文献   
13.
The aim of this study was to investigate the prevalence of pelvic organ prolapse in urban and rural women and to identify possible related factors. They were 1749 participants; one thousand four hundred seventeen (81%) urban women and 332 rural residents (19%). The urban and rural women were congruently regarding to age, parity, using oral contraceptives and postmenopausal status. The urban women were more often obese (p < 0.01), estrogen replacement users (p < 0.001), smokers (p < 0.001), with mild (p < 0.001) and high (p < 0.001) education, and they were often divorced (p < 0.05) than rural women. Rural women were more often alcohol consumers (p < 0.001), with low level of education (p < 0.001) and more often married (p < 0.05) than rural examinees. There were no association between the presence of prolapse and: weight, menopausal status, oral contraceptives and estrogen replacement using, smoking, alcohol consuming and marital status. There were not observed differences in prevalence of prior hysterectomy, urinary incontinence, uroinfectio, sexual and bowel dysfunction between both groups. The prevalence of cystocele, rectocele and uterine prolapse were similar among urban and rural participants. In conclusion, a more complete picture of factors associated with genital prolapse would include in investigation, such as molecular and genetic ones.  相似文献   
14.
The aim of this prospective study was to determine the prevalence and localization of stenotic atherosclerotic lesions of supra-aortic arteries in diabetic patients according to age and sex. Angiograms obtained by digital subtraction angiography were analyzed in 150 diabetic patients (study group) and 150 non-diabetic patients (control group) with symptoms of cerebral ischemia. Diabetic patients were found to have a significantly higher prevalence of stenotic atherosclerotic lesions of the internal carotid artery. Lesions of the large supra-aortic arteries were significantly more common in the left than in the right side of the neck (p < 0.001), but the difference between the diabetic and the non-diabetic group did not reach statistical significance. Hemodynamic conditions were found to be more important than diabetes for the occurrence of atherosclerotic lesions in these arteries. Changes in the proximal segment of the left common carotid artery were the most common finding in diabetic patients, hence attention should be paid to this localization on control examinations.  相似文献   
15.
Human and animal cremated osteological remains from twelve graves of Roman Period from archaeological site Sepkovcica near Velika Gorica (Turopolje region, NW Croatia) were analysed. Beside the content of urns and grave pits, fillings of grave vessels like bowls, pots and amphoras from twentytwo grave samples were included in this study. The preservation of osteological and dental remains of human and animal origin was very poor, majority of fragments hardly reach lengths of 10 mm. Weight of each specimen barely exceeds 100 g per person. Apart from traditional macroscopic methods of analysing cremated remains, microscopic method for determination of age at death was also tested. Fragments of femoral bone diaphysis of eighteen persons whose remains had been found on the site were analysed. Person's age at death was presented in the range of five or ten years, and the long bone fragments of a child (infants) were detected. Taxonomic position for each analysed specimen was determined by microscopic analysis of animal cremated bones. Analysis results confirm validity of microscopic method in determination of age at death for human remains and taxonomic qualification of cremated animal remains from archaeological sites.  相似文献   
16.
Theories about the first Indo-European migration are numerous. Significant contribution in attempt to resolve these theories is given by analysing skeletal material from two biggest prehistoric archaeological sites from N-E Croatia. Eight skeletons of Starcevo culture from sites "Nama" and "Hotel" at Vinkovci (6100-5500 BC) and seven skeletons of Vucedol culture from the site Vineyard Streim at Vucedol near Vukovar (3000-2500 BC) were analysed. Methods of classical anthropological analysis tried to distinguish the differences among members of both populations, while the methods of molecular genetics were used in defining possible genetic structure of both ancient populations. Established differences speak on the behalf of the theory of Maria Gimbutas about the first Indo-European migration with a cattle breeding population from the east around 3500 BC.  相似文献   
17.
Kralj  Tomislav  &#;uk  Renata  Vali&#;  Damir  Schultz  Stewart  &#;ganec  Kre&#;imir 《Hydrobiologia》2022,849(15):3315-3334
Hydrobiologia - Peracarid crustaceans contribute to the homogenization of macroinvertebrate communities as one of the most important group of aquatic invaders. This study investigated the...  相似文献   
18.
Underground environments are increasingly recognized as reservoirs of faunal diversity. Extreme environmental conditions and limited dispersal ability of underground organisms have been acknowledged as important factors promoting divergence between species and conspecific populations. However, in many instances, there is no correlation between genetic divergence and morphological differentiation. Lucifuga Poey is a stygobiotic fish genus that lives in Cuban and Bahamian caves. In Cuba, it offers a unique opportunity to study the influence of habitat fragmentation on the genetic divergence of stygobiotic species and populations. The genus includes four species and one morphological variant that have contrasting geographical distributions. In this study, we first performed a molecular phylogenetic analysis of the Lucifuga Cuban species using mitochondrial and nuclear markers. The mitochondrial phylogeny revealed three deeply divergent clades that were supported by nuclear and morphological characters. Within two of these main clades, we identified five lineages that are candidate cryptic species and a taxonomical synonymy between Lucifuga subterranea and Lucifuga teresinarum. Secondly, phylogeographic analysis using a fragment of the cytochrome b gene was performed for Lucifuga dentata, the most widely distributed species. We found strong geographical organization of the haplotype clades at different geographic scales that can be explained by episodes of dispersal and population expansion followed by population fragmentation and restricted gene flow. At a larger temporal scale, these processes could also explain the diversification and the distribution of the different species.  相似文献   
19.
The delivery of many potentially therapeutic and diagnostic compounds to specific areas of the brain is restricted by brain barriers, of which the most well known are the blood-brain barrier (BBB) and the blood-cerebrospinal fluid (CSF) barrier. Recent studies have shown numerous additional roles of these barriers, including an involvement in neurodevelopment, in the control of cerebral blood flow, and--when barrier integrity is impaired--in the pathology of many common CNS disorders such as Alzheimer's disease, Parkinson's disease and stroke.  相似文献   
20.
Neurofibromatosis type 1 (NF 1) is an autosomal dominant disorder with high index of spontaneous mutations and extremely varied and impredictible clinical manifestations. The aim of this work was to give an account of eye disorders in NF1. 132 patients of age 0-16 years with NF1 were followed up for 15 years. They were checked repeatedly for ophthalmologic disorders. Frequent eye disorders were: Lisch nodules (Iris hamartomas, IH) 78%, hyperthelorism 19.7%, bulbomotoric disorders 15.9%, disorders of the optic disc 16.7% and optic gliomas (18.9%). The highest incidence of eye disorders by NF1 patients showed Lisch nodules (IH). Its ease of clinical recognition and if present with other diagnostic signs (for instance café au lait patches) could be deemed as reliable diagnostic criterion of NF1 in childhood.  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