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41.
Attention-deficit hyperactivity disorder (ADHD) is one of the most common psychiatric disorders of childhood. The role of genetic factors in its etiology is strongly supported by family, adoption, and twin studies. Low serotonin activity has been associated in both animal and human studies with measures of impulsivity, aggression, and disinhibited behaviors, which make genes from the serotonin system reasonable candidates for ADHD susceptibility. In the present study, we investigated a polymorphism in the promoter region of the serotonin transporter (SLC6A4) and two polymorphisms (-1438 A > G and His452Tyr) in the serotonin 5-HTR2A receptor gene using family based association analyses in a sample of 243 Brazilian ADHD children and adolescents and their parents. No linkage disequilibrium between the two HTR2A polymorphisms was detected in this sample (P = 0.76). Considering several evidences from animal models for sexual dimorphism in serotonin genes expression, analyses were performed separately for the whole sample and for male probands. No evidences for biased transmissions of both HTR2A -1438 A > G and SLC6A4 polymorphisms to ADHD youths were observed. Preferential transmission of the HTR2A His452 allele was observed only in families with affected boys (P = 0.04). Our results suggest that findings from ADHD association studies for serotonin genes might be understood in the context of a gender effect, which may help to explain conflicting results in these association studies.  相似文献   
42.
Attention-Deficit/Hyperactivity Disorder (ADHD) is a complex childhood-onset psychiatric disorder characterized by marked symptoms of inattention, hyperactivity, and impulsivity. The role of genetic factors in its etiology is strongly supported by family, adoption, and twin studies. Although most of the molecular studies have investigated the dopamine D4 receptor gene (DRD4) and the dopamine transporter gene (DAT1) genes in its etiology, pharmacological and brain imaging evidences seem to indicate that genes of the adrenergic system could also be attractive for association studies. We investigated a sample of 96 Brazilian ADHD children and adolescents and their parents for the ADRA2A MspI polymorphism. Although no association with either MspI allele was observed through the haplotype relative risk (HRR) analysis, effects of the ADRA2A gene on inattention and combined (inattention + hyperactivity/impulsivity) symptom scores were detected (U = 222.5, z = 2.19, P = 0.03; and U = 208.5, z = 2.32, P = 0.02, respectively). Our results suggest that the ADRA2A gene might have a small effect on ADHD susceptibility or that this gene might modulate the severity of the disorder. They are also consistent with the noradrenergic theories of ADHD, suggesting a role for the alpha2A adrenergic receptors in the disorder.  相似文献   
43.
Fires in landfills, where used plastic packaging waste is discarded, have shown how great a fire hazard these types of materials pose. In this study, the course of thermo-oxidation of samples made of polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) based plastics was determined. Based on an analysis of the dissociation energy of bonds between atoms in a polymer molecule, the mechanisms responsible for the character and course of degradation were observed. It was found that the degradation rate of PP and PS could be a result of the stability of C-H bonds on the tertiary carbon atom. In the case of PS, due to facilitated intramolecular hydrogen transfer, stabilization of hydroperoxide, and formation of a stable tertiary alcohol molecule, the onset of degradation is shifted towards higher temperatures than in the case of PP. Notably, the PP fragmentation occurs to a greater extent due to the easier course of β-scission. In addition, it was found that during a fire, the least amount of heat would be generated by thermo-oxidation of PS-based plastics. This is a result of the formation of a styrene molecule during decomposition that, due to the high stability of bonds in the aromatic ring, escapes from the combustion zone without oxidation. It has been proven that the greatest thermal effect accompanies PET decomposition, during which a phenyl radical is produced, where the C-H bonds break more easily in comparison with the bonds of an intact ring.  相似文献   
44.
Dehydroepiandrosterone (DHEA), a precursor of immune-regulating hormones (IRH) including the androstenes, has attracted much interest over the last several decades because of its many antiaging, metabolic, and immune modulating effects. 5-Androstene-16alpha fluoro-17-one (fluasterone, also known as HE2500) is a synthetic androstene analogue that retains anti-inflammatory, antiproliferative, and immune-regulating activities of the parent molecule, but is nontoxic and practically devoid of androgenic or estrogenic side effects. In the present studies, we tested the ability of fluasterone to limit disease in the DBA mouse model of collagen-induced arthritis (CIA). We found that mice receiving injections of fluasterone displayed significant delay in onset, decrease in CIA peak score, and significant decrease of the daily mean clinical score. Benefit was associated with significant decreases in (1). bovine type II collagen (bCII)-specific IgG(1) and IgG(2a) antibody levels in serum; (2). production of TNF-alpha, IL-6, IFN-gamma, but not IL-10; (3). lymphocyte proliferative response to bCII protein; and (4). joint inflammation, erosion, and synovial proliferation as judged by histological analysis. This is the first study to report that an IRH can ameliorate ongoing disease in a CIA mouse model with relevance to RA and to correlate that finding with decreases in pro-inflammatory cytokines.  相似文献   
45.
Current consensus guidelines recommend postoperative electrocardiographic surveillance only in patients at relatively high risk of postoperative major cardiac complications, but the usefulness of electrocardiograms after major noncardiac surgery is unknown. We prospectively studied 3,570 patients who underwent major noncardiac procedures and had electrocardiograms performed in the recovery room. Rates of major cardiac complications (acute myocardial infarction, pulmonary edema, ventricular fibrillation or primary cardiac arrest, and complete heart block) were higher in patients who had new postoperative electrocardiographic abnormalities consistent with ischemia (ST-T elevation or depression or T-wave abnormalities compatible with ischemia) compared with those without ischemia (6.7% vs 1.9%, p <0.001). Multivariate analysis, after adjusting for pre- and intraoperative clinical data, indicated that the presence of ischemia on the immediate postoperative electrocardiogram was an independent predictor of major cardiac complications (odds ratio 2.2, 95% confidence interval 1.2 to 3.9, p <0.01). When patients were stratified by a preoperative Revised Cardiac Risk Index, ischemia on the immediate postoperative electrocardiogram identified patients with a higher risk of major cardiac complications in low- and high-risk subsets (odds ratio 4.9, 95% confidence interval 1.6 to 15 in lower risk patients; odds ratio 2.0, 95% confidence interval 1.0 to 3.7 in higher risk patients). We conclude that the immediate postoperative electrocardiogram is a valuable tool to adjust risk stratification, even in patients who have lower risks when undergoing noncardiac surgery.  相似文献   
46.
47.
The importance of the entomopathogenic bacterium Bacillus thuringiensis israelensis in the control of Aedes aegypti is presented. The use and potential of B. thuringiensis israelensis against the mosquito vector of dengue fever is described. Other aspects such as insect's resistance development against chemicals and advantages and constraints of using microbial control are discussed. Emphasis is given to the importance of the use of this bacterium in Brazil, which could contribute significantly to solving the mosquito problem without affecting the environment, humans and others invertebrate organisms in critical regions.  相似文献   
48.
49.
OBJECTIVE: To evaluate the validity of the multidimensional construct proposed by DSM-IV for the diagnosis of attention-deficit/hyperactivity disorder (ADHD) in a school sample of young Brazilian adolescents. METHOD: An instrument including all 18 DSM-IVADHD symptoms was administered to 1,013 students aged 12 to 14 years at 64 state schools by trained research assistants. Each symptom was rated on a Likert scale with five levels of severity (never, almost never, sometimes, frequently, and always). RESULTS: Using an exploratory factor analytic approach (principal components analysis), two factors were extracted. Factor I (hyperactivity-impulsivity) comprised eight DSM-IV hyperactive-impulsive symptoms with loadings > or =0.40. Factor II (inattention) included also eight DSM-IV symptoms of inattention. The two factors explained 34% of the total variance and had an interfactor correlation of 0.45. Latent class analysis demonstrated similar classes in males and females, but class structures were markedly different from previous analyses of parent report data. CONCLUSION: The findings support the appropriateness of the multidimensional construct introduced by DSM-IV in the diagnosis of ADHD in a different culture but emphasize the possible impact of different reporters on the results of structural model-testing.  相似文献   
50.
BACKGROUND: The effect of hospital quality of care on hospital readmission for patients with congestive heart failure (CHF) has not been widely studied. METHODS AND RESULTS: We examined the effects of clinical factors, hospital quality of care, and cardiologist involvement on 3-month readmission rates in patients with CHF by using a 125-item explicit review instrument comprising 3 major domains: admission work-up, evaluation and treatment, and readiness for discharge. During the 3 months after discharge, 59 (30%) of 205 patients were readmitted for CHF. The average evaluation and treatment score was lower for readmitted patients (63% v 58%; P = .04). The specific quality criteria differing between patients readmitted or not readmitted included the performance of any diagnostic evaluation, performance of echocardiography in patients with unknown ejection fraction or suspected valvular disease, and therapy with an angiotensin-converting enzyme inhibitor on discharge. Patients with 相似文献   
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