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   257篇
  免费   14篇
  2022年   5篇
  2021年   3篇
  2020年   3篇
  2019年   8篇
  2018年   4篇
  2017年   6篇
  2016年   2篇
  2015年   11篇
  2014年   17篇
  2013年   15篇
  2012年   11篇
  2011年   16篇
  2010年   9篇
  2009年   7篇
  2008年   19篇
  2007年   12篇
  2006年   12篇
  2005年   11篇
  2004年   15篇
  2003年   5篇
  2002年   10篇
  2001年   11篇
  2000年   12篇
  1999年   5篇
  1998年   5篇
  1996年   1篇
  1995年   4篇
  1992年   2篇
  1991年   6篇
  1990年   4篇
  1989年   4篇
  1988年   4篇
  1987年   2篇
  1985年   1篇
  1983年   1篇
  1982年   1篇
  1977年   1篇
  1975年   1篇
  1974年   2篇
  1971年   2篇
  1963年   1篇
排序方式: 共有271条查询结果,搜索用时 31 毫秒
41.
Obesity is associated with numerous risk factors and comorbidities such as hypertension, metabolic syndrome, type 2 diabetes, and cardiovascular diseases. However, numerous studies have reported an obesity paradox; the overweight and obese patients with established cardiovascular disease have better prognosis than those with a BMI <25 kg/m2. This study was designed to assess potential differences in the clinical profile and management of hypertensive outpatients with chronic ischemic heart disease in obese and lean patients that could explain these two apparently contradictory points. Overweight and obesity were defined as a BMI 25–29.9 kg/m2 and ≥30 kg/m2, respectively. Cardiovascular risk factors goals were considered according to European Society of Hypertension‐European Society of Cardiology 2003, National Cholesterol Education Program Adult Treatment Panel III and American Diabetes Association 2005 guidelines. A sample of 2,024 patients (66.8 ± 10.1 years; 31.7% women) was included. Of these, 0.1% had a BMI <20 kg/m2; 17.1% BMI 20–24.9 kg/m2; 53.7% BMI 25–29.9 kg/m2; 23.7% BMI 30–34.9 kg/m2; 4.3% BMI 35–39.9 kg/m2; and 1.1% BMI ≥40 kg/m2. The subgroup of patients with BMI ≥30 kg/m2 had a higher proportion of women, diastolic dysfunction, diabetes, dyslipidemia, left ventricular hypertrophy, and heart failure. There was an inverse relationship between risk factors control rates and BMI (all comparisons BMI 20–24.9 kg/m2 vs. 25–29.9 kg/m2 vs. ≥30 kg/m2): blood pressure (BP) control (51.7% vs. 42.4% vs. 29.2%, P < 0.001); low‐density lipoprotein cholesterol (LDL‐C) control (35.2% vs. 30.5% vs. 27.9%, P = 0.03) and diabetes control (38.6% vs. 27.6% vs. 22.2%, P = 0.023). In conclusion, in patients with hypertension and chronic ischemic heart disease, as BMI increases, the clinical profile worsens as well as risk factors control rates.  相似文献   
42.
43.
44.
Individual differences in cognitive performance are partly dependent, on genetic polymporhisms. One of the single‐nucleotide polymorphisms (SNP) of the CNR1 gene, which codes for cannabinoid receptor 1 (CB1R), is the rs2180619, located in a regulatory region of this gene (6q14–q15). The alleles of the rs2180619 are A > G; the G allele has been associated with addiction and high levels of anxiety (when the G allele interacts with the SS genotype of the 5‐HTTLPR gene). However, GG genotype is observed also in healthy subjects. Considering G allele as risk for ‘psychopathological conditions’, it is possible that GG healthy subjects do not be addicted or anxious, but would have reduced performance, compared to AA subjects, in attentional control and working memory processing. One hundred and sixty‐four healthy young Mexican‐Mestizo subjects (100 women and 64, men; mean age: 22.86 years, SD=2.72) participated in this study, solving a task where attentional control and working memory were required. GG subjects, compared to AA subjects showed: (1) a general lower performance in the task (P = 0.02); (2) lower performance only when a high load of information was held in working memory (P = 0.02); and (3) a higher vulnerability to distractors (P = 0.03). Our results suggest that, although the performance of GG subjects was at normal levels, a lower efficiency of the endocannabinoid system, probably due to a lowered expression of CB1R, produced a reduction in the performance of these subjects when attentional control and working memory processing is challenged .  相似文献   
45.
After stroke, white matter integrity can be affected both locally and distally to the primary lesion location. It has been shown that tract disruption in mirror’s regions of the contralateral hemisphere is associated with degree of functional impairment. Fourteen patients suffering right hemispheric focal stroke (S) and eighteen healthy controls (HC) underwent Diffusion Weighted Imaging (DWI) and neuropsychological assessment. The stroke patient group was divided into poor (SP; n = 8) and good (SG; n = 6) cognitive recovery groups according to their cognitive improvement from the acute phase (72 hours after stroke) to the subacute phase (3 months post-stroke). Whole-brain DWI data analysis was performed by computing Diffusion Tensor Imaging (DTI) followed by Tract Based Spatial Statistics (TBSS). Assessment of effects was obtained computing the correlation of the projections on TBSS skeleton of Fractional Anisotropy (FA) and Radial Diffusivity (RD) with cognitive test results. Significant decrease of FA was found only in right brain anatomical areas for the S group when compared to the HC group. Analyzed separately, stroke patients with poor cognitive recovery showed additional significant FA decrease in several left hemisphere regions; whereas SG patients showed significant decrease only in the left genu of corpus callosum when compared to the HC. For the SG group, whole brain analysis revealed significant correlation between the performance in the Semantic Fluency test and the FA in the right hemisphere as well as between the performance in the Grooved Pegboard Test (GPT) and theTrail Making Test-part A and the FA in the left hemisphere. For the SP group, correlation analysis revealed significant correlation between the performance in the GPT and the FA in the right hemisphere.  相似文献   
46.
In order to explore the neurobiological foundations of qualitative subjective experiences, the present study was designed to correlate objective third-person brain fMRI measures with subjective first-person identification and scaling of local, subtle, and specific somatosensory sensations, obtained directly after the imaging procedure. Thus, thirty-four volunteers were instructed to focus and sustain their attention to either provoked or spontaneous sensations of each thumb during the fMRI procedure. By means of a Likert scale applied immediately afterwards, the participants recalled and evaluated the intensity of their attention and identified specific somatosensory sensations (e.g. pulsation, vibration, heat). Using the subject''s subjective scores as covariates to model both attention intensity and general somatosensory experiences regressors, the whole-brain random effect analyses revealed activations in the frontopolar prefrontal cortex (BA10), primary somatosensory cortex (BA1), premotor cortex (BA 6), precuneus (BA 7), temporopolar cortex (BA 38), inferior parietal lobe (BA 39), hippocampus, insula and amygdala. Furthermore, BA10 showed differential activity, with ventral BA10 correlating exclusively with attention (r(32) = 0.54, p = 0.0013) and dorsal BA10 correlating exclusively with somatosensory sensation (r(32) = 0.46, p = 0.007). All other reported brain areas showed significant positive correlations solely with subjective somatosensory experiences reports. These results provide evidence that the frontopolar prefrontal cortex has dissociable functions depending on specific cognitive demands; i.e. the dorsal portion of the frontopolar prefrontal cortex in conjunction with primary somatosensory cortex, temporopolar cortex, inferior parietal lobe, hippocampus, insula and amygdala are involved in the processing of spontaneous general subjective somatosensory experiences disclosed by focused and sustained attention.  相似文献   
47.
N Cu?ado  J Barrios  J L Santos 《Génome》2000,43(6):945-948
A method of preparing two-dimensional surface spreads of plant synaptonemal complexes (SCs) associated with fluorescence in situ hybridization (FISH) has been applied to analyze the location and organization of five different highly repeated DNA sequences in rye. Our observations indicate that, depending on the type of sequence, the chromatin displays different types of organization. Telomeric sequences were seen tightly associated with the SC while other repetitive DNA sequences were found to form loops that are associated with SCs only at their bases. On the contrary, the FISH signal of a centromeric satellite had a granular appearance, reflecting that the hybridization occurs only with parts of the chromatin loops.  相似文献   
48.
49.

Background

Although fortunately very rare in countries with a temperate climate, certain factors, such as clinical or pharmacological immunosuppression, may cause Fusarium-related fungal infections to become an emerging problem. Moreover, Fusarium is one of the most important etiological agents in exogenous endophthalmitis, which is often favored by the disruption of the epithelial barriers.

Aims

The aim of this series of clinical cases is to identify characteristic clinical findings that may allow an early diagnosis and more efficient management of this ophthalmologic emergency.

Methods

Three cases of endophthalmitis due to Fusarium solani and Fusarium oxysporum, diagnosed in 2009, 2010, and 2014 in patients from two different health regions belonging to the same health system and separated by around 43 miles, are presented. The Fusarium isolates were initially identified microscopically and the species subsequently confirmed by sequencing the elongation factor alpha (EFα) and internal transcribed spacers (ITS). Susceptibility to antifungal agents was determined using the EUCAST broth dilution method.

Results

Evolution was poor as two of the three patients progressed to phthisis bulbi despite surgical measures and broad-spectrum antifungal antibiotic therapy.

Conclusions

It is essential to rapidly instigate multidisciplinary measures to combat suspected endophthalmitis due to Fusarium given the poor prognosis of this type of infection.  相似文献   
50.
Benzoxazinoids are key defence chemicals in cereals that are known to affect several aspects of aphid biology. However, little is known about how they affect aphid physiology. In the present study, we report changes in the whole‐body proteomic profiles of a 2,4‐dihydroxy‐7‐methoxy‐1,4‐benzoxazin‐3‐one (DIMBOA)‐susceptible genotype of the grain aphid Sitobion avenae (F.) after being exposed to wheat cultivars containing contrasting levels of DIMBOA. The proteome is analyzed after 14 days (short term) and 28 days (long term) of rearing on these cultivars. Seventy‐two proteins are differentially regulated among the treatments and 49 are identified. Exposure to high‐DIMBOA plants results in a higher number of proteins regulated long term. DIMBOA exposure in S. avenae initially generates greater cellular activities, mostly involving cytoskeleton function and possibly related to detoxification. This function appears to be unimportant at long term and is eventually replaced by effects on metabolism function and homeostasis. Taken together, the results of the present study show that the responses of aphids to the secondary plant compounds, such as DIMBOA, exhibit a temporal dynamic in the proteome, possibly helping aphids to overcome the effect of these toxic compounds.  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