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   1592篇
  免费   207篇
  国内免费   163篇
  2024年   5篇
  2023年   46篇
  2022年   47篇
  2021年   103篇
  2020年   105篇
  2019年   133篇
  2018年   77篇
  2017年   82篇
  2016年   62篇
  2015年   94篇
  2014年   131篇
  2013年   150篇
  2012年   76篇
  2011年   80篇
  2010年   65篇
  2009年   72篇
  2008年   75篇
  2007年   56篇
  2006年   71篇
  2005年   48篇
  2004年   40篇
  2003年   40篇
  2002年   32篇
  2001年   25篇
  2000年   23篇
  1999年   20篇
  1998年   13篇
  1997年   28篇
  1996年   16篇
  1995年   16篇
  1994年   18篇
  1993年   19篇
  1992年   10篇
  1991年   12篇
  1990年   10篇
  1989年   8篇
  1988年   6篇
  1987年   8篇
  1986年   8篇
  1985年   6篇
  1984年   3篇
  1983年   7篇
  1982年   3篇
  1979年   1篇
  1978年   2篇
  1977年   2篇
  1976年   2篇
  1974年   2篇
  1973年   1篇
  1972年   1篇
排序方式: 共有1962条查询结果,搜索用时 187 毫秒
991.
The purpose of this study was to determine the prevalence of causative non-dermatophytic filamentous fungi in onychomycosis. Totally 1,222 (1,222 × 3 = 3,666) samples of nail scrapings from 1,146 patients (from 76 patients two specimens: both from finger- and toe-nails) with prediagnosis of onychomycosis sent to the Mycology Laboratory from the Clinic of Dermatology, Ege University Hospital, Izmir, Turkey, July 2001–December 2003, were prospectively studied with conventional mycological procedures. The set criteria for the diagnosis of onychomycosis due to non-dermatophytic molds were: (1) Observation of fungal elements in 15% KOH-preparations made from nail scrapings, (2) growth of the same mold in all three consecutive cultures of the specimens taken three times from the same patient with one-week intervals, (3) no growth of a dermatophyte or yeast in three consecutive cultures. As agents of onychomycosis molds were detected in 33 (9%), dermatophytes in 175 (48%), yeasts in 150 (41%), and mixed (two different fungi) in 8 (2%) patients. In cases of mold onychomycosis, 11 (33%) had finger-nail and 22 (67%) toe-nail infection; 25 (76%) were female and 8 (24%) male; and 27 (82%) were above 40 years of age. The agents of mold onychomycosis, in order of frequency, were Aspergillus niger (7), Acremonium spp. (6), Fusarium spp. (6), Ulocladium spp. (4), sterile mycelia (2), Alternaria sp. (1), Aspergillus flavus (1), Aspergillus fumigatus (1), Aspergillus terreus (1), Cladosporium sp. (1), Paecilomyces spp. (1), Scopulariopsis sp. (1) and Trichoderma sp. (1). In conclusion, this study showed that non-dermatophytic molds were responsible for nearly 10% of onychomycoses cases attending the dermatology outpatient clinic of a university hospital in Izmir, Turkey. Since molds are common contaminants in the laboratory, cultures from consecutively taken nail scrapings should be made and carefully evaluated in order to diagnose a “mold onychomycosis”.  相似文献   
992.
A novel methodology for the diagnosis of acute infections using FTIR microspectroscopy (FTIR-MSP) data on blood components and cluster analysis is presented. Blood samples were collected from 11 patients suffering from various infections and 16 age-matched healthy human controls. Blood components such as white blood cells, red blood cells, and plasma were isolated using standard procedures and FTIR-MSP of these components was utilized. A cluster analysis of the FTIR spectra was performed. The spectra obtained from the three blood components of patients were different from those of controls. The FTIR spectra of white blood cells from patients suffering infections were significantly different from the controls. Cluster analyses of averaged FTIR-MSP spectra of white blood cells provided 100% classification between patients and healthy controls.  相似文献   
993.
A comparison among various histological techniques for the detection of the parasite Bonamia ostreae in oysters Ostrea edulis was performed to evaluate their sensitivity and suitability for different purposes. The comparison involved examination of histological sections, tissue imprints from gills, digestive gland, gonad and heart, and haemolymph cell monolayers, prepared through various protocols. Every technique produced some false negative. The haemolymph cell monolayers were more sensitive than tissue imprints and histological sections. Heart imprints provided the highest sensitivity among tissue imprints. Examination of histological sections was among the least sensitive techniques. Four procedures for estimation of infection intensity were compared. Some differences in accuracy for the estimation of infection intensity between haemolymph cell monolayers and histological sections (HS) were detected: there was a very good agreement when the infection appeared low or heavy in HS but it was not so good in the remaining cases. The results suggest the need for a critical review of the recommendations of the "Office Internationale des Epizooties" and the European Union for diagnosis of bonamiosis.  相似文献   
994.
The powdery mildew fungus Leveillula taurica (Erysiphales) is reported for the first time from the monocot Triglochin maritima (Juncaginaceae), a widespread salt marsh plant that causes economic losses because of its high toxicity to young livestock. This is the first report of an erysiphaceous fungus on a member of the Juncaginaceae. Morphological data, obtained by light and scanning electron microscopy, and ITS sequence data provided evidence that this fungus is referable to L. taurica. The ITS sequence for this fungus was identical with those reported for L. taurica hosted by Capsicum annuum in Australia and Elaeagnus angustifolia in Iran. This is the third host species and second monocot, in addition to Allium cepa and Solanum tuberosum, reported for L. taurica from Washington State, where the fungus was unreported before 2004.  相似文献   
995.
This paper describes the natural history of the clinical syndrome of Alzheimer's disease (AD) including the cognitive deficit, the neuropsychiatric symptoms, impact on daily functioning, risk factors, medical complications and impact on the use of health-care resources. The clinical presentation of the disease varies greatly from the prodrome through end stage; instruments used to quantify the severity of each aspect of the disease have been developed and are described along with their use in clinical drug trials. Drug treatments for AD are usually developed by first showing a positive effect on the cognitive deficit, with later studies investigating drug effects on other clinical aspects of the disease.  相似文献   
996.
Introduction: Frailty is consequent to age-dependent deregulation of several biological pathways and systems, encompassing namely sarcopenia, age-associated hormonal derangements, inflammation, and nutritional or metabolic deficiencies. Although the prevalence of frailty is usually between 10% and 20% in the general elderly population, its overall burden will increase exponentially along with the predictable prolongation of life expectancy. Risk prediction and early diagnosis will hence become pivotal for mitigating the clinical, social, and economic impact of this condition. The currently available research suggests that no single laboratory biomarker can efficiently help predicting or diagnosing frailty. However, its multifaceted pathogenesis suggests that a multi-marker approach, preceded by preliminary identification of specific proteomic signatures, may be the most promising strategy in frailty diagnostics.

Areas covered: This review critically analyzes recent proteomic studies exploring protein profiles in non-frail and frail subjects.

Expert commentary: Results of some recent proteomic studies attest that muscle proteome, chronic low-grade inflammation (inflammaging), along with characteristic vascular and hemostasis proteomic profiles, may help predict or diagnose frailty. Larger prospective studies are needed for confirming these findings and enabling their replication in real life scenarios. Albeit proteomic research in the field of age-dependent biologic impairment is in embryo, proteomics holds the greatest potential in frailty diagnostics.  相似文献   

997.
Infectious diseases are among the common leading causes of morbidity and mortality worldwide. Associated with the emergence of new infectious diseases, the increasing number of antimicrobial‐resistant isolates presents a serious threat to public health and hospitalized patients. A microbial pathogen may elicit several host responses and use a variety of mechanisms to evade host defences. These methods and mechanisms include capsule, lipopolysaccharides or cell wall components, adhesions and toxins. Toxins inhibit phagocytosis, cause septic shock and host cell damages by binding to host surface receptors and invasion. Bacterial and fungal pathogens are able to apply many different toxin‐dependent mechanisms to disturb signalling pathways and the structural integrity of host cells for establishing and maintaining infections Initial techniques for analysis of bacterial toxins were based on in vivo or in vitro assessments. There is a permanent demand for appropriate detection methods which are affordable, practical, careful, rapid, sensitive, efficient and economical. Aptamers are DNA or RNA oligonucleotides that are selected by systematic evolution of ligands using exponential enrichment (SELEX) methods and can be applied in diagnostic applications. This review provides an overview of aptamer‐based methods as a novel approach for detecting toxins in bacterial and fungal pathogens.  相似文献   
998.
Context: Circulating MicroRNAs (miRNAs) are emerging as novel biomarkers for tumour.

Objective: Evaluate the diagnostic potential of plasma miR-200b-3p in oral squamous cell carcinoma (OSCC).

Materials and methods: miR-200b-3p was detected by qRT-PCR in paired pre-operative and post-operative plasmas from 80 OSCC patients and 80 healthy controls.

Results: Plasma miR-200b-3p was significantly upregulated in OSCC, and it was higher in WHO II/III grade than WHO I grade. The AUC of miR-200b-3p for OSCC was 0.9173. miR-200b-3p was significantly downregulated after surgery. High miR-200b-3p expression was associated with poor prognosis.

Discussion and conclusion: Plasma miR-200b-3p could be a potential diagnostic biomarker for OSCC.  相似文献   

999.
WENTING WANG  ZIJIAN LI  JUAN FENG 《Cytotherapy》2018,20(10):1204-1219
In the past, exosomes have been thought of as cellular dust. Today, they are thought to be carriers of real biomarkers and intercellular biological information. The composition of exosomes differs according to their source, and the subsequent information they carry, such as protein, microRNA or mRNA, may also be different. Recent studies have demonstrated that exosomes in ischemic diseases can help to make an early diagnosis, and in cellular experiments and animal models, exosomes promote angiogenesis, restrain cell apoptosis and reduce inflammation, among other actions, to protect ischemic organs. There is evidence that these protective effects are related to microRNAs in exosomes. In this review, we discuss the use of exosomes for early diagnosis of ischemic diseases and recent advances in the therapeutic use of exosomes in cell and mammalian models of ischemic diseases.  相似文献   
1000.
布鲁氏菌(Brucella,简称布氏菌)是一种重要的人兽共患病原菌,布鲁氏菌病常发生在牛、羊、猪等家畜中,主要通过接触传播给人类。人类在感染该菌的早期并无特异性症状,其临床表现多样,若不能及时诊断并予以干预,可导致严重关节疼痛和菌血症,甚至引起死亡。布鲁氏菌病一旦广泛发病,不但对畜牧业造成巨大经济损失,还会严重威胁公共安全,因此,布鲁氏菌的快速准确诊断对防治疾病的发展具有重要意义。目前,针对该病原体常见的实验室检测方法包括微生物检测法、免疫学检测法、分子生物学检测法等。本文将就人感染布鲁氏菌的实验室诊断研究进展作以简要综述。  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