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   3156篇
  免费   148篇
  国内免费   11篇
耳鼻咽喉   51篇
儿科学   119篇
妇产科学   44篇
基础医学   481篇
口腔科学   78篇
临床医学   160篇
内科学   490篇
皮肤病学   56篇
神经病学   258篇
特种医学   220篇
外科学   390篇
综合类   51篇
预防医学   336篇
眼科学   62篇
药学   273篇
中国医学   6篇
肿瘤学   240篇
  2023年   17篇
  2022年   22篇
  2021年   54篇
  2020年   33篇
  2019年   56篇
  2018年   64篇
  2017年   67篇
  2016年   77篇
  2015年   73篇
  2014年   116篇
  2013年   123篇
  2012年   231篇
  2011年   221篇
  2010年   106篇
  2009年   99篇
  2008年   177篇
  2007年   173篇
  2006年   184篇
  2005年   170篇
  2004年   136篇
  2003年   132篇
  2002年   105篇
  2001年   57篇
  2000年   55篇
  1999年   53篇
  1998年   17篇
  1996年   14篇
  1994年   13篇
  1993年   16篇
  1992年   45篇
  1991年   38篇
  1990年   40篇
  1989年   45篇
  1988年   33篇
  1987年   35篇
  1986年   28篇
  1985年   19篇
  1984年   25篇
  1983年   18篇
  1979年   22篇
  1977年   17篇
  1975年   14篇
  1974年   15篇
  1973年   17篇
  1972年   14篇
  1971年   16篇
  1970年   16篇
  1967年   20篇
  1933年   13篇
  1932年   12篇
排序方式: 共有3315条查询结果,搜索用时 328 毫秒
81.
Five cases of giant inflammatory polyps associated with idiopathic inflammatory bowel disease are reported. Polyps produced intestinal obstruction in three cases; consequently, surgery was performed. In a further two cases, intestinal bleeding was improved by endoscopic polypectomy. Electron microscopy showed fibroblasts, myofibroblasts, mast cells, lymphocytes, collagen fibers, capillaries, and venules. Remnants of the original mucosal epithelial cells, smooth muscle cells, and hypertrophic autonomous nerve plexuses were noted. Nerve fibers were interwoven with the matrix of the polyps. Mast cells were closely linked with vessels, nerves, and collagen fibers. They may have an important role in the excessive granulation, angiogenesis, and fibrotic process in giant inflammatory polyps.  相似文献   
82.

Background and study aims

Occult hepatitis B infection (OBI) is known to be mostly prevalent in chronic hepatitis C (CHC) patients and OBI reactivation might be life-threatening in patients undergoing interferon (IFN)-free direct acting antiviral (DAA) therapy. As previous studies have revealed a relationship between OBI and non-response to IFN-based antiviral therapy, the aim of the current study was to determine if there was a higher prevalence of OBI in IFN non-responders than responders.

Patients and Methods

This retrospective cross-sectional study was conducted in CHC patients who had previously received IFN-based antiviral therapy. Serum samples of 100 HBsAg negative CHC patients were tested for HBV DNA, anti-HBc IgG, anti-HBs, ALT and AST. The presence of OBI was compared between 50 IFN responders and 50 IFN non-responders. Patients with a history of previous HBV infection, patients with evidence of cirrhosis and patients who had received IFN therapy within the last one year were excluded from the study.

Results

Anti-HBc IgG positivity was determined in 53% of the patients. HBV DNA positivity, indicating OBI was determined in 1 (1%) patient. This patient was anti-HBc IgG positive, anti-HBs negative, ALT and AST levels were normal. The HBV DNA and anti-HBc IgG positivity rates were higher in the non-responder group than in the responder group, but the difference was not statistically significant (p?=?0.31 and p?=?0.07 respectively).

Conclusion

According to the results of this study, the prevalence of OBI is lower than expected amongst CHC patients in Turkey and it may not be necessary to apply routine screening to IFN non-responders for OBI infection before DAA therapy. However, there is a need for multicentre studies with larger patient series.  相似文献   
83.
Summary Parallel studies were performed using microfluorimetric DNA determination and X-ray microanalysis on the same thyroid biopsy material to compare the intranuclear DNA and monovalent electrolyte contents (Na+, K+, Cl). Samples were taken from apparently healthy, adenomatous, and cancerous parts of human thyroid glands removed surgically. The time interval was less than 1 min. The tissues were classified by the pathologist into four main classes: 1) Normal thyroid tissue; 2) benign adenomas; 3) differentiated (follicular and papillary) carcinomas; and 4) anaplastic cancers. The results revealed that the level of aneuploidization showed an increase parallel with the malignancy of the studied tumor. At the same time, a similar tendency was found in the average values of the intranuclear Na+:K+ ratios. The results obtained in this way confirm the possibility that the electric properties of the cell membrane, that is the sustained membrane depolarization, may have a role in the regulation of DNA synthesis and in mitogenesis. These results may offer new diagnostic and/or therapeutic possibilities.  相似文献   
84.
INTRODUCTION: Conventional percutaneous coronary intervention for the treatment of in-stent restenosis (ISR) has shown a high rate of ISR (30-55%). Considering the need for both extrusion of hyperplastic intima and additional stent expansion, a cutting balloon might be more effective for the treatment of ISR. METHODS: We prospectively assessed the immediate and 8-month outcome of balloon angioplasty using the Barath Cutting Balloon in 100 consecutive patients (mean age: 60.5 +/- 10.8 years, 71% male). RESULTS: In 73 lesions (73%), a good result was reached with the cutting balloon only. In 21 lesions (21%) postdilatation and in 6 lesions (6%) predilatation with a conventional balloon was necessary. The mean inflation pressure was 8.7 +/- 2.0 (range: 6.0-18.0) atm. Before the procedure the mean minimal luminal diameter (MLD) was 0.95 +/- 0.45 mm. Quantitative coronary analysis showed a mean diameter stenosis of 65%+/- 16%. Immediately after the procedure the mean MLD was 2.42 +/- 0.54 mm with a mean diameter stenosis of 19%+/- 13%. Two patients died during the follow-up period (1 stroke, 1 nonvascular). At 8-month follow-up 26 patients (26%) reported to have anginal complaints CCS class II-IV of whom 16 (16%) needed target lesion revascularization. CONCLUSION: Treatment of ISR using the Barath Cutting Balloon can be performed safely with good immediate results and a relatively low need for repeated target lesion revascularization at 8-month follow-up.  相似文献   
85.
86.
Journal of Autism and Developmental Disorders - The original version of the article has contained an error in Table 3 (the organization of Module 2 items into the Basic Social Communication and...  相似文献   
87.

The persistence of residual infection is one of the major factors in failure of the Global Programme to Eliminate Lymphatic Filariasis (GPELF). The present study aims to explore the status of sheath antibody and regulatory T cells (Tregs) known to play key roles in clearance of parasite and patent filarial infection, in individuals with residual infection after MDA. A total of 61 microfilaremic (Mf) individuals were followed up after at least 6 rounds of MDA. Infection status of subjects was assessed through the detection of Mf and circulating filarial antigen (CFA). Antibodies to Mf sheath were determined by immuno-peroxidase assay (IPA). The expression of Tregs was measured by a flow cytometer. IL-10 and IFN-γ were evaluated using the commercially available ELISA kit. The sheath antibody was present in subjects who have cleared both Mf and CFA and absent in individuals who were found to be Mf /CFA positive. Further individuals carrying infection have significantly high levels of Tregs and IL-10. A positive correlation was observed between Tregs, IL-10, and CFA in infected individuals. In contrast, a negative correlation was observed between IFN-γ and IL-10 in both infected and uninfected subjects. Our study reveals that the absence of a sheath antibody and a high level of Tregs and IL-10 are the hallmarks of the persistence of residual filarial infection.

  相似文献   
88.
Journal of Clinical Immunology - Severe combined immunodeficiency is an inborn error of immunity characterized by impairments in the numbers and functions of T and B lymphocytes due to various...  相似文献   
89.
Annals of Nuclear Medicine - 68Ga-DOTA-NaI-octreotide (DOTANOC) is a promising new alternative to 18F-fluorodeoxyglucose (FDG) for imaging inflammation in cardiac sarcoidosis. The aim of the study...  相似文献   
90.
BackgroundThe medical application domain has been a great challenge for information technology solutions for decades, especially when the target process has been complex and multidisciplinary such as chemotherapy processes.ObjectiveTo evaluate the impact of a homegrown protocol based information system on the efficiency of chemotherapy workflow processes in an outpatient setting.MethodsA day care unit of the Hematology/Oncology outpatient clinic of Erasmus Medical Center was the setting for this study. The study consisted of comparison of pre- and post-implementation of four workflow efficiency related external indicators: turn-around times of a commonly administered chemotherapy course (Paclitaxel–Carboplatin), chemotherapy course administration postponing rate, the rate of recording course administration time, and patient admission rate of the outpatient clinic. The data was gathered retrospectively from patient charts and information systems’ log files. For the purpose of turn-around-time 109 Paclitaxel–Carboplatin chemotherapy courses of pre-implementation were compared to 118 those of post-implementation. For the other indicators: 247 chemotherapy courses pre-implementation were compared to 324 courses post-implementation. The process maps of pre- and post-implementation were also compared to each other.ResultsThe implementation of the system improved the process by removing repetition and sequencing of the tasks. Following the implementation, chemotherapy postponing decreased by 17.2% (Z = ?4.723, P = .000) and there were 5.7% less records with missing administration time (Z = ?3.047, P = .002). The admission rate increased 1.9 patient per working day (t(94) = ?5.974, P = .000). The overall turn-around-time reduced 18.9 min following the implementation (t(169) = 3.48, P = .001). In a multivariate multiple regression model the reduction in turn-around time was related to the implementation of the system (Pillai's Trace = 0.159, F(4,161) = 7.613, P = .000).ConclusionInformation systems based on treatment protocols can reduce communication and synchronization needs between the stakeholders in a complex workflow process. These systems can help reengineering the process and improve workflow efficiency by removing unnecessary sequencing and repetitions of tasks.  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