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   1632篇
  免费   67篇
  国内免费   3篇
耳鼻咽喉   12篇
儿科学   27篇
妇产科学   16篇
基础医学   182篇
口腔科学   346篇
临床医学   83篇
内科学   289篇
皮肤病学   18篇
神经病学   91篇
特种医学   57篇
外科学   159篇
综合类   6篇
预防医学   240篇
眼科学   47篇
药学   86篇
中国医学   18篇
肿瘤学   25篇
  2023年   14篇
  2022年   19篇
  2021年   58篇
  2020年   39篇
  2019年   40篇
  2018年   46篇
  2017年   38篇
  2016年   31篇
  2015年   38篇
  2014年   56篇
  2013年   86篇
  2012年   101篇
  2011年   132篇
  2010年   83篇
  2009年   58篇
  2008年   90篇
  2007年   102篇
  2006年   91篇
  2005年   73篇
  2004年   64篇
  2003年   58篇
  2002年   57篇
  2001年   28篇
  2000年   29篇
  1999年   18篇
  1998年   20篇
  1997年   17篇
  1996年   11篇
  1995年   9篇
  1994年   7篇
  1993年   13篇
  1992年   7篇
  1991年   8篇
  1990年   8篇
  1989年   12篇
  1988年   12篇
  1987年   11篇
  1986年   6篇
  1985年   20篇
  1984年   6篇
  1981年   5篇
  1979年   8篇
  1975年   9篇
  1973年   8篇
  1972年   4篇
  1970年   4篇
  1969年   5篇
  1968年   6篇
  1967年   8篇
  1965年   4篇
排序方式: 共有1702条查询结果,搜索用时 265 毫秒
31.
BACKGROUND: Clinical manifestations of dengue vary in different areas of endemicity and between specific age groups, whereas predictors of outcome have remained controversial. In Brazil, the disease burden predominantly affects adults, with an increasing trend toward progression to dengue hemorrhagic fever (DHF) noted. METHODS: A cohort of adults with confirmed cases of dengue was recruited in central Brazil in 2005. Patients were classified according to the severity of their disease. Associations of antibody responses, viremia levels (as determined by real-time polymerase chain reaction [PCR]), and serotypes (as determined by multiplex PCR) with disease severity were evaluated. RESULTS: Of the 185 symptomatic patients >14 years of age who had a confirmed case of dengue, 26.5% and 23.2% were classified as having intermediate dengue fever (DF)/DHF (defined as internal hemorrhage, plasma leakage, manifested signs of shock, and/or thrombocytopenia [platelet count, < or =50,000 platelets/mm3]) and DHF, respectively. The onset of intermediate DF/DHF and DHF occurred at a late stage of disease, around the period of defervescence. Patients with DHF had abnormal liver enzyme levels, with a >3-fold increase in aspartate aminotransferase level, compared with the range of values considered to be normal. Overall, 65% of patients presented with secondary infections with dengue virus, with such infection occurring in similar proportions of patients in each of the 3 disease category groups. Dengue virus serotype 3 (DV3) was the predominant serotype, and viremia was detected during and after defervescence among patients with DHF or intermediate DF/DHF. CONCLUSIONS: Viremia was detected after defervescence in adult patients classified as having DHF or intermediate DF/DHF. Secondary infection was not a predictor of severe clinical manifestation in adults with infected with the DV3 serotype.  相似文献   
32.
According to the WHO, 16-18 million people in Central and South America are infected by Trypanosoma cruzi. Chagasic achalasia affects between 7.1% and 10.6% of the population. The aim of this study was to evaluate the effects of Botox injections in the clinical response and esophageal function of patients with dysphagia due to chagasic achalasia. In total, 24 symptomatic patients with chagasic achalasia were randomly chosen to receive Botulinum Toxin (BT) or saline injected by endoscopy in the lower esophageal sphincter (LES). Patients were monitored with a clinical score of dysphagia and an objective assessment (esophagograms, scintillography, manometry, and nutritional assessment) for a period of 6 months. Clinical improvement of dysphagia was statistically significant (P < 0.001) in patients receiving BT when compared with the placebo. There was no significant difference in the placebo group regarding clinical score, LES basal pressure and esophageal emptying time. Esophageal emptying time in the toxin group was significantly lower than in the placebo (P=0.04) after 90 days. There were non-significant increases in esophageal emptying of 25.36% and 17.39%, respectively, at 90 and 180 days, in the BT group (P=0.266). Gender, age, and baseline LES pressure did not influence the response to BT. Our data strongly suggests that intrasphincteric injection of BT in LES is clinically effective in the treatment of chagasic achalasia.  相似文献   
33.
Incubation of human platelets, human neutrophils, or highly metastatic mouse lymphoma cells with sulfate-labeled extracellular matrix (ECM) results in heparanase-mediated release of labeled heparan sulfate cleavage fragments (0.5 less than Kav less than 0.85 on Sepharose 6B). This degradation was inhibited by native heparin both when brought about by intact cells or their released heparanase activity. Degradation of heparan sulfate in ECM may facilitate invasion of normal and malignant cells through basement membranes. The present study tested the heparanase inhibitory effect of nonanticoagulant species of heparin that might be of potential use in preventing heparanase mediated extravasation of bloodborne cells. For this purpose, we prepared various species of low-sulfated or low-mol-wt heparins, all of which exhibited less than 7% of the anticoagulant activity of native heparin. N-sulfate groups of heparin are necessary for its heparanase inhibitory activity but can be substituted by an acetyl group provided that the O-sulfate groups are retained. O-sulfate groups could be removed provided that the N positions were resulfated. Total desulfation of heparin abolished its heparanase inhibitory activity. Heparan sulfate was a 25-fold less potent heparanase inhibitor than native heparin. Efficiency of low-mol-wt heparins to inhibit degradation of heparan sulfate in ECM decreased with their main molecular size, and a synthetic pentasaccharide, representing the binding site to antithrombin III, was devoid of inhibitory activity. Similar results were obtained with heparanase activities released from platelets, neutrophils, and lymphoma cells. We propose that heparanase inhibiting nonanticoagulant heparins may interfere with dissemination of bloodborne tumor cells and development of experimental autoimmune diseases.  相似文献   
34.
35.

AIM:

to evaluate the clinical applicability of outcomes, according to the Nursing Outcomes Classification (NOC) in the evolution of orthopedic patients with Impaired Physical Mobility

METHOD:

longitudinal study conducted in 2012 in a university hospital, with 21 patients undergoing Total Hip Arthroplasty, evaluated daily by pairs of trained data collectors. Data were collected using an instrument containing five Nursing Outcomes, 16 clinical indicators and a five point Likert scale, and statistically analyzed.

RESULTS:

The outcomes Body Positioning: self-initiated, Mobility, Knowledge: prescribed activity, and Fall Prevention Behavior presented significant increases in mean scores when comparing the first and final evaluations (p<0.001) and (p=0.035).

CONCLUSION:

the use of the NOC outcomes makes it possible to demonstrate the clinical progression of orthopedic patients with Impaired Physical Mobility, as well as its applicability in this context.  相似文献   
36.
37.
Patients with mucopolysaccharidosis type VI (MPS VI) present with a wide range of disease severity and clinical manifestations, with significant functional impairment and shortened lifespan. Enzyme replacement therapy (ERT) with galsulfase has been shown to improve clinical and biochemical parameters including patient survival, quality of life and growth. The present study is a resurvey of 34 Brazilian MPS VI patients with rapidly progressive disease (classical phenotype) who initiated ERT with galsulfase under five years of age and had been on ERT until data collection in 2019, with few exceptions (n = 4 patients who died before 2019).Anthropometric measures, urinary glycosaminoglycans, and data regarding cardiac, orthopedic, neurologic, sleep apnea, hearing and ophthalmologic outcomes were filled in by specialists. Pubertal development, clinical complications, hospitalizations, and surgeries were also assessed.In this resurvey study, treatment with galsulfase has shown to be safe and well tolerated in MPS VI patients who initiated ERT under the age of 5 years and who have been undergoing ERT for approximately 10 years. Mortality rate suggests that early initiation of ERT may have a positive impact on patients' survival, improving but not preventing disease progression and death. MPS VI patients on ERT also showed improved growth velocity and the pubertal development was normal in all surviving patients.Follow-up data on pneumonia and hospitalization suggest that early ERT may have a protective effect against major respiratory complications. Cardiac valve disease progressed since their prior evaluation and spinal cord compression was observed in a large number of patients, suggesting that these disease complications were not modified by ERT.  相似文献   
38.
The traditional protocol for guided surgery in a completely edentulous patient is time-consuming, requiring the fabrication of a radiographic guide and a dual cone beam computed tomography (CBCT) scan. Using intraoral scanners to scan the edentulous ridge and the existing denture has been advocated to simplify the process. This technique offers a versatile, precise, and predictable method for the digital planning workflow in edentulous patients for either a fixed or removable restoration. In addition, this approach can help improve the quality of the guide produced by reducing CBCT artifacts associated with the existing denture, as well as capture the soft-tissue contour to further improve the fit of the surgical guide.  相似文献   
39.
This article shows the follow-up of several cases of maxillary sinusitis of dental (usually endodontic) origin, with different manifestations, diagnostic challenges, and outcomes.Cases from 14 patients from 3 countries and treated by 7 different endodontists are presented, all of them with inflammatory sinus changes represented by mucositis, osteoperiostitis, and/or partial/full obstruction. All cases showed dental and/or sinus signs/symptoms that resolved after dental management. In 13 cases, the sinus condition had an endodontic origin, 4 of them concurrently with periodontal involvement. In 1 case, sinusitis was caused by trauma to the face. All cases but 1 had a satisfactory response of the periradicular tissues and maxillary sinus to treatment that consisted of root canal therapy, root amputation, extraction, or trauma management.The successful management of most cases reported in this article emphasizes the importance of endodontics as a specialty engaged in saving teeth and promoting health not only in the oral cavity but also in other areas that may be affected by infections of endodontic origin, including the maxillary sinus.  相似文献   
40.
ObjectiveViruses on environmental surfaces, in saliva and other body fluids represent risk of contamination for general population and healthcare professionals. The development of vaccines and medicines is costly and time consuming. Thus, the development of novel materials and technologies to decrease viral availability, viability, infectivity, and to improve therapeutic outcomes can positively impact the prevention and treatment of viral diseases.MethodsHerein, we discuss (a) interaction mechanisms between viruses and materials, (b) novel strategies to develop materials with antiviral properties and oral antiviral delivery systems, and (c) the potential of artificial intelligence to design and optimize preventive measures and therapeutic regimen.ResultsThe mechanisms of viral adsorption on surfaces are well characterized but no major breakthrough has become clinically available. Materials with fine-tuned physical and chemical properties have the potential to compromise viral availability and stability. Emerging strategies using oral antiviral delivery systems and artificial intelligence can decrease infectivity and improve antiviral therapies.SignificanceEmerging viral infections are concerning due to risk of mortality, as well as psychological and economic impacts. Materials science emerges for the development of novel materials and technologies to diminish viral availability, infectivity, and to enable enhanced preventive and therapeutic strategies, for the safety and well-being of humankind.  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