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   1345篇
  免费   57篇
  国内免费   6篇
耳鼻咽喉   8篇
儿科学   67篇
妇产科学   9篇
基础医学   85篇
口腔科学   33篇
临床医学   89篇
内科学   362篇
皮肤病学   44篇
神经病学   116篇
特种医学   29篇
外科学   223篇
综合类   8篇
一般理论   2篇
预防医学   32篇
眼科学   145篇
药学   78篇
中国医学   1篇
肿瘤学   77篇
  2024年   1篇
  2023年   19篇
  2022年   35篇
  2021年   96篇
  2020年   43篇
  2019年   56篇
  2018年   79篇
  2017年   35篇
  2016年   36篇
  2015年   43篇
  2014年   66篇
  2013年   84篇
  2012年   111篇
  2011年   131篇
  2010年   83篇
  2009年   47篇
  2008年   101篇
  2007年   82篇
  2006年   72篇
  2005年   59篇
  2004年   35篇
  2003年   23篇
  2002年   22篇
  2001年   5篇
  2000年   6篇
  1999年   3篇
  1998年   4篇
  1997年   1篇
  1996年   3篇
  1994年   3篇
  1993年   1篇
  1992年   2篇
  1991年   4篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1987年   2篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1979年   1篇
  1974年   1篇
  1972年   1篇
  1971年   1篇
  1970年   2篇
  1969年   1篇
排序方式: 共有1408条查询结果,搜索用时 15 毫秒
41.
42.
43.
Invasive Salmonella has been reported to induce apoptosis of macrophages as a part of its infection process, which may allow it to avoid detection by the innate immune system. However, the bacterial components capable of inducing apoptosis, particularly under the environments offered by the host have not been fully identified. Therefore, in the present study, attempts were made to evaluate the apoptotic potential of Salmonella enterica serovar Typhi (S. typhi) outer membrane protein expressed under stress conditions like iron, oxidative and anaerobic simulating the in vivo situations encountered by the pathogen. Analysis of data revealed that a coordinately expressed 69kDa outer membrane protein (OMP) expressed with enhanced intensity under iron, oxidative and anaerobic stress conditions caused apoptotic cell death in 51% of macrophages, whereas OMPs of S. typhi extracted under normal conditions accounted for apoptotic cell death in only 31% of macrophages. A significantly enhanced activity of caspase-3 was observed during macrophage-apoptosis induced by this protein. A significant increase in the extent of lipid peroxidation (levels of oxidant) and decrease in the activities of antioxidants was also observed which correlated with the increased generation of tumor necrosis factor-alpha, interleukine-1alpha and interleukine-6. These results suggest that caspase-3 and tumor necrosis factor-alpha in conjunction with other cytokines may induce apoptotic cell death through the up-regulation of oxidants and down-regulation of antioxidants. These findings may be relevant for the better understanding of the disease pathophysiology and for the future developments of diagnostic and preventive strategies during the host-pathogen interactions.  相似文献   
44.

Gastro-oesophageal reflux disease (GORD) after one anastomosis gastric bypass (OAGB) remains a concern. We reviewed the current literature on revisional surgery after OAGB for GORD. MEDLINE, EMBASE, and PubMed databases were searched. We identified 21 studies, appraising 13,658 OAGB patients. A total of 230 (1.6%) patients underwent revisional surgery for GORD. Revision to Roux-en-Y configuration was performed in 211 (91.7%) patients. Six (2.6%) patients had a Braun entero-enterostomy added to the OAGB. Thirteen (5.6%) patients underwent excluded stomach fundoplication (ESF). Reflux symptoms resolved in 112 (48.6%) patients, persisted in 13 (5.6%) patients, and were not reported in 105 (45.6%) patients. Revisional surgery after OAGB for GORD appears to be rare, and when required, conversion to Roux-en-Y configuration is the commonest choice.

  相似文献   
45.
Purpose:Vitreoretinal lymphoma (VRL) is the most common intraocular lymphoma (IOL). This can be either primary or secondary to the central nervous system lymphoma. The diagnosis of primary intraocular lymphoma (PIOL) currently relies on clinical diagnosis and cytological analysis of the vitreous or subretinal biopsy. Although most cases are diagnosed without much issue, the limited amount of vitreous fluid, subjectivity in cytological reporting, and special expertise in ocular pathology make the diagnosis challenging. MYD88 L265P mutation has been implicated to have diagnostic utility in PIOL. In this study, we screened consecutive vitreous biopsies for the presence of MYD88 L265P mutation to understand its diagnostic utility compared to conventional cytological analysis.Methods:Cytological analysis and MYD88 L265P mutation by PCR-based sequencing and restriction fragment length polymorphism (RFLP) were carried out on consecutive vitreous and subretinal biopsies collected from 21 patients. The diagnostic utility of the cytology and MYD88 L265P mutation analysis were compared.Results:Out of the 21 patients, 15 had clinical suspicion of having PIOL. Out of these suspected cases of PIOL, nine were confirmed on follow-up, while six were diagnosed as other intraocular pathologies. Diagnostic utility of MYD88 L265P mutation analysis revealed a sensitivity of 88.9%, specificity of 91.6%, positive and negative predictive value of 88.9% and 91.7%, respectively. Diagnostic accuracy of 90.5% was achieved with the mutation analysis that shows the superiority of MYD88 in both ruling in and ruling out PIOL. The diagnostic utility of MYD88 L265P mutation was superior to conventional cytological analysis.Conclusion:The analysis of MYD88 L265P mutation is reliable and efficient in the diagnosis of PIOL.  相似文献   
46.
Purpose

Patients with chronic kidney disease are predisposed to heart rhythm disorders including atrial fibrillation (AF). Several studies have suggested that radiofrequency catheter ablation of AF improves renal function. However, little data exists for pulmonary vein isolation with cryoballoon ablation (CBA). The purpose of this study is to assess change in renal function following CBA for AF.

Method

This is a single-center retrospective study that included patients who underwent CBA for AF between 2011 and 2016. Patients were grouped by baseline-estimated glomerular filtration rate (eGFR): ≥?90 (Stage G1), 60–89.9 (Stage G2), and 30–59.9 mL/min/1.73 m2 (Stage G3). Change in eGFR was assessed >?3 months post-ablation.

Results

A total of 306 patients with both pre- and post-ablation serum creatinine measurements available were included. Baseline eGFRs for Stages G1, G2, and G3 patients were 103.5?±?12.9 (n?=?82), 74.7?±?8.2 (n?=?184), and 52.6?±?6.6 mL/min/1.73 m2 (n?=?40), respectively. Renal function was assessed 310.8?±?104.2 days post-ablation. Average intra-procedural contrast use was 58.4?±?23.8 mL. There was no significant change in eGFR following CBA in Stage G1 patients (p?=?0.10). For those with Stages G2 and G3 renal function, eGFR improved by 6.1% (4.2 mL/min/1.73 m2, p?<?0.01) and 13.8% (7.2 mL/min/1.73 m2, p?<?0.01), respectively. This improvement was seen regardless of the presence or absence of recurrent atrial arrhythmias.

Conclusions

CBA for AF may be associated with an improvement in renal function, particularly among those with a reduced baseline eGFR despite recurrence of atrial arrhythmias and intra-procedural contrast use.

  相似文献   
47.
48.
49.
50.

Objective

To assess, by socioeconomic setting, the effect of nationwide vaccination against species A rotavirus (RVA) on childhood diarrhoea-related hospitalizations in Mexico.

Methods

Data on children younger than 5 years who were hospitalized for diarrhoea in health ministry hospitals between 1 January 2003 and 31 December 2011 were collected from monthly discharge reports. Human development indexes were used to categorize the states where hospitals were located as having generally high, intermediate or low socioeconomic status. Annual rates of hospitalization for diarrhoea – per 10 000 hospitalizations for any cause – were calculated. Administrative data were used to estimate vaccine coverage.

Findings

In the states with high, intermediate and low socioeconomic status, coverage with a two-dose monovalent RVA vaccine – among children younger than 5 years – had reached 93%, 86% and 71%, respectively, by 2010. The corresponding median annual rates of hospitalization for diarrhoea – per 10 000 admissions – fell from 1001, 834 and 1033 in the “prevaccine” period of 2003–2006, to 597, 497 and 705 in the “postvaccine” period from 2008 to 2011, respectively. These decreases correspond to rate reductions of 40% (95% confidence interval, CI: 38–43), 41% (95% CI: 38–43) and 32% (95% CI: 29–34), respectively. Nationwide, RVA vaccination appeared to have averted approximately 16 500 hospitalizations for childhood diarrhoea in each year of the postvaccine period.

Conclusion

Monovalent RVA vaccination has substantially reduced childhood diarrhoea-related hospitalizations for four continuous years in discretely different socioeconomic populations across Mexico.  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