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   1948篇
  免费   123篇
  国内免费   8篇
耳鼻咽喉   69篇
儿科学   29篇
妇产科学   29篇
基础医学   299篇
口腔科学   178篇
临床医学   129篇
内科学   462篇
皮肤病学   31篇
神经病学   198篇
特种医学   27篇
外科学   145篇
综合类   1篇
预防医学   143篇
眼科学   41篇
药学   178篇
中国医学   21篇
肿瘤学   99篇
  2024年   2篇
  2023年   16篇
  2022年   24篇
  2021年   73篇
  2020年   45篇
  2019年   69篇
  2018年   92篇
  2017年   48篇
  2016年   62篇
  2015年   70篇
  2014年   129篇
  2013年   158篇
  2012年   198篇
  2011年   218篇
  2010年   84篇
  2009年   82篇
  2008年   142篇
  2007年   122篇
  2006年   125篇
  2005年   90篇
  2004年   85篇
  2003年   70篇
  2002年   44篇
  2001年   3篇
  2000年   4篇
  1999年   3篇
  1998年   5篇
  1997年   2篇
  1996年   1篇
  1995年   6篇
  1994年   1篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1987年   1篇
  1986年   1篇
  1984年   1篇
排序方式: 共有2079条查询结果,搜索用时 62 毫秒
1.

Background

Vaccination of children with 13-valent pneumococcal conjugate vaccine (PCV13) led to declines in vaccine-type pneumococcal nasopharyngeal carriage among adults through indirect effects. In August 2014, PCV13 immunization of all U.S. adults ≥65?years of age was recommended. This study sought to define prevalence and serotype distribution of pneumococcal carriage among adults ≥65?years of age and to describe risk factors for colonization soon after introduction of PCV13 in adults.

Methods

A cross-sectional survey of non-institutionalized U.S. adults ≥65?years of age was conducted in four states in 2015–2016. Demographic information, risk factors for disease, PCV13 vaccination history, and nasopharyngeal (NP) and oropharyngeal (OP) swabs were collected. NP and OP swabs were processed separately and pneumococcal isolates were serotyped by Quellung reaction. Antimicrobial susceptibility of pneumococcal isolates was performed. NP swabs also underwent real-time PCR for pneumococcal detection and serotyping.

Results

Of 2989 participants, 45.3% (1354/2989) had been vaccinated with PCV13. Fifty-five (1.8%) carried pneumococcus (45 identified by culture and 10 by real-time PCR only) and PCV13 serotypes were found in eight (0.3%) participants. Almost half (22/45) of pneumococcal isolates were not susceptible to at least one of the antibiotics tested. Vaccine-type carriage among vaccinated and unvaccinated individuals was similar (0.2% vs. 0.1%, respectively). Respiratory symptoms were associated with higher odds of pneumococcal colonization (adjusted OR: 2.1; 95% CI?=?1.1–3.8).

Conclusions

Pneumococcal carriage among non-institutionalized adults ≥65?years of age was very low. Less than 0.5% of both vaccinated and unvaccinated individuals in our study carried vaccine-type serotypes. Over a decade of PCV vaccination of children likely led to indirect effects in adults. However, given the low vaccine-type carriage rates we observed in an already high PCV13 adult coverage setting, it is difficult to attribute our findings to the direct versus indirect effects of PCV13 on adult carriage.  相似文献   
2.
3.
4.
5.
6.
7.
Unresectable neuroendocrine neoplasms (NENs) often poorly respond to standard therapeutic approaches. Alkylating agents, in particular temozolomide, commonly used to treat high-grade brain tumors including glioblastomas, have recently been tested in advanced or metastatic NENs, where they showed promising response rates. In glioblastomas, prediction of response to temozolomide is based on the assessment of the methylation status of the MGMT gene, as its product, O6 -methylguanine-DNA methyltransferase, may counteract the damaging effects of the alkylating agent. However, in NENs, such a biomarker has not been validated yet. Thus, we have investigated MGMT methylation in 42 NENs of different grades and from various sites of origin by two different approaches: in contrast to methylation-specific PCR (MSP), which is commonly used in glioblastoma management, amplicon bisulfite sequencing (ABS) is based on high-resolution, next-generation sequencing and interrogates several additional CpG sites compared to those covered by MSP. Overall, we found MGMT methylation in 74% (31/42) of the NENs investigated. A higher methylation degree was observed in welldifferentiated tumors and in tumors originating in the gastrointestinal tract. Comparing MSP and ABS results, we demonstrate that the region analyzed by the MSP test is sufficiently informative of the MGMT methylation status in NENs, suggesting that this predictive parameter could routinely be interrogated also in NENs.  相似文献   
8.
9.
10.

Objectives

Translate, cross-culturally adapt and validate the Rapid Geriatric Assessment (RGA) for Brazilian community-dwelling adults.

Design

Cross-sectional study, using a quantitative approach.

Setting

Urban population from the city of São Carlos, located in the interior of São Paulo State, Brazil. Participants: 148 individuals aged 60 or over.

Measurements

Participants were assessed using the RGA, Fried Frailty Phenotype, International Physical Activity Questionnaire - long version, Addenbrooke´s Cognitive Exam - Revised Version, Mini Nutritional Assessment, short Form - 36, EuroQol 5-Dimension, Geriatric Depression Scale - short version, in addition to performing Dual Energy X-ray Absorptiometry to diagnose sarcopenia, according to the criteria established by the European Working Group on Sarcopenia in Older People.

Results

In the translation and adaption process of the RGA, steps recommended by the literature were followed: initial translation, synthesis of translations, backward translation, evaluation from the panel of judges, and pre-test. When evaluating the psychometric properties of the scale, satisfactory reliability (internal consistency and stability) and validity (content, concurrent criterion and convergent, divergent and discriminant construct) were verified.

Conclusion

The Brazilian version of the RGA is reliable and valid, and can be used in the Brazilian context to evaluate the elderly population.
  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