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   935篇
  免费   30篇
  国内免费   8篇
耳鼻咽喉   5篇
儿科学   19篇
妇产科学   17篇
基础医学   86篇
口腔科学   59篇
临床医学   76篇
内科学   223篇
皮肤病学   18篇
神经病学   43篇
特种医学   156篇
外科学   113篇
综合类   27篇
预防医学   63篇
眼科学   4篇
药学   47篇
中国医学   2篇
肿瘤学   15篇
  2023年   4篇
  2022年   12篇
  2021年   28篇
  2020年   14篇
  2019年   14篇
  2018年   23篇
  2017年   16篇
  2016年   16篇
  2015年   23篇
  2014年   35篇
  2013年   44篇
  2012年   61篇
  2011年   49篇
  2010年   58篇
  2009年   41篇
  2008年   48篇
  2007年   63篇
  2006年   46篇
  2005年   47篇
  2004年   27篇
  2003年   27篇
  2002年   16篇
  2001年   11篇
  2000年   11篇
  1999年   13篇
  1998年   23篇
  1997年   22篇
  1996年   26篇
  1995年   25篇
  1994年   18篇
  1993年   3篇
  1992年   17篇
  1991年   14篇
  1990年   10篇
  1989年   9篇
  1988年   14篇
  1987年   5篇
  1986年   7篇
  1985年   7篇
  1984年   4篇
  1983年   2篇
  1982年   2篇
  1981年   2篇
  1980年   3篇
  1979年   2篇
  1977年   3篇
  1976年   2篇
  1971年   1篇
  1968年   3篇
  1928年   1篇
排序方式: 共有973条查询结果,搜索用时 15 毫秒
51.
52.
53.
Placebo controls play a critical role in the evaluation of any pharmacotherapy. This review surveys the placebo arm in 12 randomized controlled trials (RCTs) investigating burning mouth syndrome (BMS) and documents a positive placebo response in 6 of them. On average, treatment with placebos produced a response that was 72% as large as the response to active drugs. The lack of homogeneity in the use of placebos adds to the difficulty in comparing results and aggregating data. Future RCTs investigating BMS would benefit from larger sample sizes, adequate follow‐up periods, and use of a standard placebo.  相似文献   
54.

The demand for revisional bariatric surgery after sleeve gastrectomy (SG) has increased, but the ideal procedure remains unclear. A systematic review and meta-analysis were performed to compare the outcomes of weight loss and safety of one-anastomosis gastric bypass (OAGB) and Roux-en-Y gastric bypass (RYGB) as revisional procedures for failed SG. Four retrospective comparative studies were included, comprising 499 individuals. Patients submitted to OAGB had a more significant total weight loss (TWL) (MD =  − 5.89%; 95% CI − 6.80 to − 4.97) after revisional surgery. Overall early complication rate was similar between procedures (RD = 0.04; 95% CI: − 0.05 to 0.12). Limited and heterogeneous data prevent meaningful conclusions, but the present analysis suggests that OAGB has a better TWL after revisional surgery.

Graphical abstract
  相似文献   
55.

Summary

This study investigated whether osteoporosis/osteopenia has an influence on the progression of periodontitis in postmenopausal women. The findings highlight that postmenopausal women with osteoporosis/osteopenia had a greater chance of presenting periodontitis than those with normal bone mineral density, particularly among nonusers of osteoporosis medications and women with a greater number of remaining teeth, showing that osteoporosis/osteopenia has had an influence on the progression of periodontitis.

Introduction

This study investigated whether osteoporosis/osteopenia has an influence on the progression of periodontitis in postmenopausal women and explored the effects of use of osteoporosis medication and tooth loss on this association.

Methods

This case–control study involved 521 postmenopausal women, with minimum age of 50 years, in Feira de Santana, Bahia, Brazil. Sociodemographic characteristics, health conditions/medications, and lifestyle habits were recorded. A complete periodontal examination was performed and periodontitis was diagnosed. Bone mineral density was evaluated through lumbar spine and femoral bone densitometry, obtained using dual-energy X-ray absorptiometry. Logistic regression was used to calculate the strength of association between the occurrences of osteoporosis/osteopenia and periodontitis.

Results

Women with osteoporosis/osteopenia were twice as likely to present periodontitis, as were those with normal bone mineral density, even after adjusting for smoking, age, family income, and last visit to dentist (odds ratios (OR)adjusted?=?2.24, 95 % CI [1.24–4.06], p?=?0.008). Among nonusers of osteoporosis medication (ORadjusted?=?2.51, 95 % CI [1.33–4.73], p?=?0.004) and women with at least 10 remaining teeth (ORadjusted?=?2.50 95 % CI [1.18–5.27], p?=?0.02), the odds ratio was higher and statistically significant.

Conclusions

These findings highlight that postmenopausal women with osteoporosis/osteopenia had a greater chance of presenting periodontitis than those with normal bone mineral density, particularly among nonusers of osteoporosis medications and women with a greater number of remaining teeth.  相似文献   
56.
BackgroundDamage to the renal microvasculature is a hallmark of renal ischemia-reperfusion injury (IRI)–mediated AKI. The miR-17∼92 miRNA cluster (encoding miR-17, -18a, -19a, -20a, -19b-1, and -92a-1) regulates angiogenesis in multiple settings, but no definitive role in renal endothelium during AKI pathogenesis has been established.MethodsAntibodies bound to magnetic beads were utilized to selectively enrich for renal endothelial cells from mice. Endothelial-specific miR-17∼92 knockout (miR-17∼92endo−/−) mice were generated and given renal IRI. Mice were monitored for the development of AKI using serum chemistries and histology and for renal blood flow using magnetic resonance imaging (MRI) and laser Doppler imaging. Mice were treated with miRNA mimics during renal IRI, and therapeutic efficacies were evaluated.ResultsmiR-17, -18a, -20a, -19b, and pri–miR-17∼92 are dynamically regulated in renal endothelial cells after renal IRI. miR-17∼92endo−/− exacerbates renal IRI in male and female mice. Specifically, miR-17∼92endo−/− promotes renal tubular injury, reduces renal blood flow, promotes microvascular rarefaction, increases renal oxidative stress, and promotes macrophage infiltration to injured kidneys. The potent antiangiogenic factor thrombospondin 1 (TSP1) is highly expressed in renal endothelium in miR-17∼92endo−/− after renal IRI and is a target of miR-18a and miR-19a/b. miR-17∼92 is critical in the angiogenic response after renal IRI, which treatment with miR-18a and miR-19b mimics can mitigate.ConclusionsThese data suggest that endothelial-derived miR-17∼92 stimulates a reparative response in damaged renal vasculature during renal IRI by regulating angiogenic pathways.  相似文献   
57.
Conclusion  In heart transplant recipients with isolated focal CAD involving the proximal or mid portion of a vessel, revascularization options exist. However, because of the increased risk of the procedure and uncertain impact on outcome, it probably is important to document evidence of provokable ischemia, especially if the patient is symptom free. Stress myocardial perfusion imaging can document ischemia related to specific coronary artery lesions and may be an important adjunct to decision making in this difficult patient population. One of the most important recent developments in single photon emission computed tomography (SPECT) myocardial perfusion imaging is the ability to acquire these studies in conjunction with electrocardiogrpahic (ECG) gating. A recommendation for incorporating ECG gating as a routine during SPECT cardiac perfusion scintigraphy is appropriate for at least four reasons: there is extensive peer-reviewed literature attesting to its value; the practice is now widespread; practitioners in diverse settings (academia dn private practive) regularly use it; and the hardware and software requirements are widely available. In addition, ASNC-sponsored continuing medical education programs for the past several years have emphasized the added information provided by ECG gating. The purpose of this position statemetn therefore is to formally encourage routine ECG gating along with SPECT myocardial perusion studies, unless technical reasons preclude this. p ]Although the principleis clear-cut, there will need to be more investigations and, ultimately, procedural guidelines to assist in optimizing acquisition and processing parametes in relation to different hardware and radiopharmaceuticals. This is a first step in a new and expanding direction for myocardial perfusion scintigraphy. Timothy M. Bateman, MD President American Society of Nuclear Cardiology  相似文献   
58.
59.
Recent serologic, immunoprotection, and pathogenesis studies identified the Lig proteins as key virulence determinants in interactions of leptospiral pathogens with the mammalian host. We examined the sequence variation and recombination patterns of ligA, ligB, and ligC among 10 pathogenic strains from five Leptospira species. All strains were found to have intact ligB genes and genetic drift accounting for most of the ligB genetic diversity observed. The ligA gene was found exclusively in L. interrogans and L. kirschneri strains, and was created from ligB by a two-step partial gene duplication process. The aminoterminal domain of LigB and the LigA paralog were essentially identical (98.5 ± 0.8% mean identity) in strains with both genes. Like ligB, ligC gene variation also followed phylogenetic patterns, suggesting an early gene duplication event. However, ligC is a pseudogene in several strains, suggesting that LigC is not essential for virulence. Two ligB genes and one ligC gene had mosaic compositions and evidence for recombination events between related Leptospira species was also found for some ligA genes. In conclusion, the results presented here indicate that Lig diversity has important ramifications for the selection of Lig polypeptides for use in diagnosis and as vaccine candidates. This sequence information will aid the identification of highly conserved regions within the Lig proteins and improve upon the performance characteristics of the Lig proteins in diagnostic assays and in subunit vaccine formulations with the potential to confer heterologous protection.  相似文献   
60.
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