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   6138篇
  免费   630篇
  国内免费   20篇
耳鼻咽喉   42篇
儿科学   137篇
妇产科学   179篇
基础医学   960篇
口腔科学   116篇
临床医学   699篇
内科学   1283篇
皮肤病学   177篇
神经病学   447篇
特种医学   207篇
外科学   810篇
综合类   74篇
一般理论   3篇
预防医学   589篇
眼科学   100篇
药学   499篇
中国医学   20篇
肿瘤学   446篇
  2023年   64篇
  2022年   117篇
  2021年   250篇
  2020年   169篇
  2019年   180篇
  2018年   206篇
  2017年   172篇
  2016年   169篇
  2015年   200篇
  2014年   255篇
  2013年   326篇
  2012年   489篇
  2011年   488篇
  2010年   276篇
  2009年   217篇
  2008年   372篇
  2007年   403篇
  2006年   356篇
  2005年   343篇
  2004年   331篇
  2003年   281篇
  2002年   242篇
  2001年   97篇
  2000年   59篇
  1999年   64篇
  1998年   47篇
  1997年   27篇
  1996年   24篇
  1995年   31篇
  1994年   31篇
  1993年   35篇
  1992年   31篇
  1991年   24篇
  1990年   35篇
  1989年   27篇
  1988年   17篇
  1987年   24篇
  1986年   18篇
  1985年   24篇
  1984年   31篇
  1983年   22篇
  1982年   24篇
  1981年   26篇
  1980年   22篇
  1979年   20篇
  1978年   14篇
  1977年   10篇
  1975年   12篇
  1974年   14篇
  1973年   8篇
排序方式: 共有6788条查询结果,搜索用时 359 毫秒
911.
912.
Six-month outcomes are evaluated from a 9-site quasi-experimental study of women with mental health and substance use disorders who have experienced physical or sexual abuse who enrolled in either comprehensive, integrated, trauma-informed, and consumer/survivor/recovering person-involved services (N = 1023) or usual care (N = 983). Mental health, post-traumatic stress symptoms, and substance use outcomes are assessed with multilevel regression models, controlling for program and personal characteristics. Person-level variables predict outcomes independent of intervention condition and, to a small extent, moderate intervention and program effects. In sites where the intervention condition provided more integrated counseling than the comparison condition, there are increased effects on mental health and substance use outcomes; these effects are partially mediated by person-level variables. These results encourage further research to identify the longer-term effects of integrated counseling for women with co-occurring disorders and trauma histories.  相似文献   
913.
914.
PURPOSE: To estimate the prevalence of posterior embryotoxon (PE) in the general ophthalmic clinic and to identify any features of PE that suggest that it is pathological rather than physiological. METHODS: Over 700 consecutive patients of all ages were examined with the slit lamp during their routine eye clinic appointment. Patients with posterior embryotoxon were invited to return for full ocular examination including keratometry, corneal topography, and gonioscopy. RESULTS: In all, 49 out of 723 patients were found to have PE. This gives a prevalence of 6.8% with an age range of 18 months to 95 years. There was a higher prevalence in the younger age group of 22.5% (age range 18 months to 20 years) compared to 5.9% in the older age range (21-95 years). A total of 29 patients with PE returned for further examination. Six patients had glaucoma (two with Axenfeld's syndrome and one with aniridia), and one had ocular hypertension. In all, 20 patients had bilateral PE on slit-lamp examination, which increased to 24 with gonioscopy. The majority of the PE was seen temporally (97.9%) and limited to a few clock hours. Gonioscopy showed that eight patients with PE had associated inferior pigmentation of schwalbes line. CONCLUSION: This large series found the prevalence of PE the general ophthalmic clinic to be 6.8%. Its presence should prompt careful anterior segment examination, including gonioscopy, to identify any associated abnormalities that may carry a risk of glaucoma. Children should also be assessed for any associated systemic or genetic abnormality.  相似文献   
915.
916.

Background

An outbreak of acute hemorrhagic conjunctivitis occurred in Cuba in 2008 and 2009.

Objective

To determinate the etiological agent associated with the Cuban outbreaks of acute hemorrhagic conjunctivitis during 2008 and 2009.

Study design

Conjunctival swabs and/or faecal samples from 382 patients with clinical diagnosis suggestive of acute hemorrhagic conjunctivitis were subject to viral culture in HEp-2 human laryngeal epidermoid carcinoma cells. Positive samples were identified by a specific Coxsackievirus A24 variant PCR and the 3C protease region of 16 isolates was sequenced for phylogenetic analysis.

Results

Enterovirus cytopathic effect was observed in 138 cases (36%). A higher percent of CA24v was recovered from faecal samples, 19 out of 45 cases (42.2%), than from conjunctival swabs, 127 out of 355 samples (35.8%). All isolates were identified as Coxsackievirus A24 variant. Phylogenetic analysis revealed that 2008 and 2009 Cuban outbreaks were caused by the same virus strains and that isolates were closely related to those from Taiwan (2006-2007), China (2007-2008) and Singapore (2005) with a bootstrap value of 71%.

Conclusions

Outbreaks of acute hemorrhagic conjunctivitis occurred in Cuba in 2008 and 2009 were caused by Coxsackievirus A24 variant. The faecal-oral route is another mode of transmission of CA24v in the acute hemorrhagic conjunctivitis outbreaks. Phylogenetic analysis of Cuban CA24v strains involved in an acute hemorrhagic conjunctivitis outbreak in 2008 and 2009 confirms a new introduction of the CA24 variant into the Americas from South-east Asia.  相似文献   
917.
ObjectiveTo conduct a systematic review of the literature to identify, describe and assess interventions of information and communication technology on the processes of communication and associated patient outcomes within hospital settings.Materials and methodsStudies published from the years 1996 to 2010 were considered and were selected if they described an evaluation of information and communication technology interventions to improve clinical communication within hospitals. Two authors abstracted data from full text articles, and the quality of individual articles were appraised. Results of interventions were summarized by their effect.ResultsThere were 18 identified studies that evaluated the use of interventions that included alphanumeric paging, hands-free communication devices, mobile phones, smartphones, task management systems and a display based paging system. Most quantitative studies used a before and after study design and were of lower quality. Of all the studies, there was only one prospective randomized study, but this study used only simulated communication events. Quantitative studies identified improved perceptions of communication and some improvement in communication metrics. Qualitative studies described improvements in efficiency of communication but also issues of loss of control and reliability.ConclusionsDespite the rapid advancement in information and communications technology over the last decade, there is limited evidence suggesting improvements in the ability of health professionals to communicate effectively. Given the critical nature of communication, we advocate further evaluation of information and communication technology designed to improve communication between clinicians. Outcome measures should include measures of patient-oriented outcomes and efficiency for clinicians.  相似文献   
918.
Tumor biomarkers increasingly provide information for predicting outcomes with chemotherapeutic regimens (personalized medicine). Topo2A is a DNA helicase targeted by anthracyclines, cytotoxic therapeutics used in both adjuvant and palliative treatments of breast cancer. TOP2A gene amplification/deletion is implicated in response to anthracycline-based chemotherapy. We describe an approach for analyzing formalin-fixed, paraffin-embedded breast tumors on tissue microarrays with TOP2A fluorescence in situ hybridization coupled with cytokeratin immunofluorescence to target tumor cells. Stained tissue from patient specimens was imaged and analyzed using Metafer/Metacyte (Metasystems, Waltham, MA, USA), including customized image classifiers. TOP2A/CEN17 ratios of 2.0 or greater (amplified) and 0.8 or less (deleted) were observed for 10.0% and 6.1% of the patients, respectively. Patient outcomes for adjuvant chemotherapy (cyclophosphamide-epirubicin-fluorouracil, cyclophosphamide-methotrexate-fluorouracil, no chemotherapy) were evaluated. No statistical significance was achieved for clinical end points regarding TOP2A status in anthracycline-treated patients. However, patients with TOP2A aberrations receiving methotrexate-based therapy exhibited a significant decrease in 5-year distant disease-free survival and breast cancer-specific overall survival, especially for patients with TOP2A deletions (disease-free survival: hazard ratio, 5.31 [P = .001], and breast cancer-specific overall survival: hazard ratio, 6.45 [P ≤ .001]). No significant differences were seen in patients included in the no-chemotherapy group. Topo2A protein levels were assessed by immunohistochemistry with no correlative statistical relevance to immunofluorescence/fluorescence in situ hybridization-based prognosis for cyclophosphamide-epirubicin-fluorouracil or cyclophosphamide-methotrexate-fluorouracil groups. Interestingly, aberrant (under)expressing patients in the no-chemotherapy group exhibited better 5-year distant disease-free survival (hazard ratio, 0.39; P = .004), trending toward more favorable breast cancer-specific overall survival (hazard ratio, 0.61; P = .11). Our results indicate a strategy by which fluorescence in situ hybridization scoring targeted to cytokeratin-positive tumor cells may provide a tool for added precision and efficiency in TOP2A evaluation from tumor tissue.  相似文献   
919.
Japanese encephalitis virus (JEV) is a human pathogenic, mosquito-borne flavivirus that is endemic/epidemic in Asia. JEV is rarely detected or isolated from blood or cerebrospinal fluid (CSF), and detection of IgM is generally diagnostic of the infection. The flavivirus nonstructural glycoprotein NS1 is released transiently during flavivirus replication. The aim of this study was to set up a quantitative JEV NS1 antigen capture assay. A soluble hexameric form of JEV NS1 protein was produced in a stable Drosophila S2 cell clone and purified from supernatant fluids. Two IgG1 monoclonal antibodies (MAbs) with high affinity against two different epitopes of JEV NS1 antigen were used to develop an antigen-capture assay with a limit of detection of 0.2 ng ml−1 NS1. Up to 1 μg ml−1 JEV NS1 protein was released in supernatants of mammalian cells infected with JEV but <10 ng ml−1 was released in sera of virus-infected mice before the onset of encephalitis and death. Moreover, NS1 protein was detected at low levels (<10 ng ml−1) in 23.8% of sera and in 10.5% of CSF of patients diagnosed as IgM-positive for JEV. This quantitative test of NS1 protein is proposed for highly specific diagnosis of acute infection with JEV genotypes I to IV.  相似文献   
920.
Atopic dermatitis (AD), a chronic, pruritic, inflammatory skin disease, is histopathologically characterized by epidermal hyperplasia and infiltration of T cells, mast cells, and eosinophils. Clinical study and basic research have established that IL-4 plays an important role in the pathogenesis of AD. In this report, using HaCat cells, we show that CCL26, a chemokine for eosinophils, is up-regulated by IL-4 at both the mRNA and protein levels. IL-4 also enhances CCL26 promoter activity. Serial 5' deletion of the promoter and mutagenesis study reveal that the proximal Stat site is the key response element for IL-4 regulation of CCL26. Although IL-4 increases phosphorylation of both Stat3 and Stat6, it only activates Stat6 as shown by dominant negative studies. In addition, we found that IL-4 induces Stat6 nuclear translocation and stimulates phosphorylation of Jak1 and Jak2 but not Tyk2. IL-4 up-regulation of CCL26 can be suppressed by Jak inhibitors in a dose-dependent manner. Taken together, results of this investigation reveal that IL-4 signals through the Jak1, 2/Stat6 pathway in keratinocytes to stimulate CCL26 expression and this may provide an explanation for the pathogenesis of AD.  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