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   8525篇
  免费   419篇
  国内免费   119篇
耳鼻咽喉   45篇
儿科学   401篇
妇产科学   947篇
基础医学   1335篇
口腔科学   45篇
临床医学   405篇
内科学   462篇
皮肤病学   40篇
神经病学   1278篇
特种医学   81篇
外科学   496篇
综合类   658篇
预防医学   1500篇
眼科学   198篇
药学   695篇
  4篇
中国医学   146篇
肿瘤学   327篇
  2023年   132篇
  2022年   272篇
  2021年   352篇
  2020年   333篇
  2019年   304篇
  2018年   257篇
  2017年   275篇
  2016年   293篇
  2015年   284篇
  2014年   495篇
  2013年   588篇
  2012年   474篇
  2011年   538篇
  2010年   377篇
  2009年   451篇
  2008年   420篇
  2007年   399篇
  2006年   336篇
  2005年   258篇
  2004年   230篇
  2003年   187篇
  2002年   146篇
  2001年   117篇
  2000年   106篇
  1999年   71篇
  1998年   71篇
  1997年   75篇
  1996年   64篇
  1995年   70篇
  1994年   54篇
  1993年   58篇
  1992年   54篇
  1991年   49篇
  1990年   37篇
  1989年   36篇
  1988年   25篇
  1987年   26篇
  1986年   37篇
  1985年   83篇
  1984年   66篇
  1983年   69篇
  1982年   83篇
  1981年   62篇
  1980年   61篇
  1979年   51篇
  1978年   52篇
  1977年   36篇
  1976年   39篇
  1975年   28篇
  1974年   23篇
排序方式: 共有9063条查询结果,搜索用时 15 毫秒
1.
《Cancer radiothérapie》2022,26(4):611-615
In order to provide more convenient irradiation regimens for patient comfort, radiation facility organization and health expenses, new hypofractionated protocols have been evaluated. Moderately (dose/fraction: 2.3 to 3 Gy), then ultra (dose/fraction: 5.2 to 6.1 Gy) hypofractionated irradiations were first validated. The current question is: is it possible to go forward using extreme hypofractionated regimens (EHR) based on 1 to 3 fractions. Different irradiation techniques are under investigation. However, brachytherapy remains the smartest way to deliver a high dose in a small volume. We report prospective and retrospective study results which evaluated EHR for breast and prostate brachytherapy. While oncological outcome and toxicity profile appear extremely encouraging for low-risk breast cancer after a 1 to 4 fractions (6.25 to 20 Gy/fraction), the use of a single fraction of 19 to 23 Gy appears debatable for prostate cancer. Brachytherapy represents an emblematic example of EHR but longer follow-up and more mature results are awaited in order to specify the right indications and refine the EQD2 calculation method including new biological and technical factors.  相似文献   
2.
《Vaccine》2022,40(52):7604-7612
Background and ObjectiveVaccine uptake during pregnancy remains low. Our objectives were to describe 1) development and adaptation of a clinician communication training intervention for maternal immunizations and 2) obstetrics and gynecology (ob-gyn) clinician and staff perspectives on the intervention and fit for the prenatal care context.MethodsDesign of the Motivational Interviewing for Maternal Immunizations (MI4MI) intervention was based on similar communication training interventions for pediatric settings and included presumptive initiation of vaccine recommendations (“You’re due for two vaccines today”) combined with motivational interviewing (MI) for hesitant patients. Interviews and focus group discussions were conducted with ob-gyn clinicians and staff in five Colorado clinics including settings with obstetric physicians, certified nurse midwives (CNMs), and clinician-trainees. Participants were asked about adapting training to the ob-gyn setting and their implementation experiences. Feedback was incorporated through iterative changes to training components.ResultsInterview and focus group discussion results from participants before (n = 3), during (n = 11) and after (n = 25) implementation guided intervention development and adaptation. Three virtual, asynchronous training components were created: a video and two interactive modules. This virtual format was favored due to challenges attending group meetings; however, participants noted opportunities to practice skills through role-play were lacking. Training modules were adapted to include common challenging vaccine conversations and live-action videos. Participants liked interactive training components and use of adult learning strategies. Some participants initially resisted the presumptive approach but later found it useful after applying it in their practices. Overall, participants reported that MI4MI training fit well with the prenatal context and recommended more inclusion of non-clinician staff.ConclusionsMI4MI training was viewed as relevant and useful for ob-gyn clinicians and staff. Suggestions included making training more interactive, and including more complex scenarios and non-clinician staff.  相似文献   
3.
PurposeAccording to the social determinants of health framework, income inequality is a potential risk factor for adverse mental health. However, few studies have explored the mechanisms suspected to mediate this relationship. The current study addresses this gap through a mediation analysis to determine if social support and community engagement act as mediators linking neighbourhood income inequality to maternal anxiety and depressive symptoms within a cohort of new mothers living in the City of Calgary, Canada.MethodsData collected at three years postpartum from mothers belonging to the All Our Families (AOF) cohort were used in the current study. Maternal data were collected between 2012 and 2015 and linked to neighbourhood socioeconomic data from the 2006 Canadian Census. Income inequality was measured using Gini coefficients derived from 2006 after-tax census data. Generalized structural equation models were used to quantify the associations between income inequality and mental health symptoms, and to assess the potential direct and indirect mediating effects of maternal social support and community engagement.ResultsIncome inequality was not significantly associated with higher depressive symptoms (β = 0.32, 95%CI = −0.067, 0.70), anxiety symptoms (β = 0.11, 95%CI = −0.39, 0.60), or lower social support. Income inequality was not associated with community engagement. For the depression models, higher social support was significantly associated with lower depressive symptoms (β = −0.13, 95%CI = −0.15, −0.097), while community engagement was not significantly associated with depressive symptoms (β = 0.059, 95%CI = −0.15, 0.27). Similarly, for the anxiety models, lower anxiety symptoms were significantly associated with higher levels of social support (β = −0.17, 95%CI = −0.20, −0.13) but not with higher levels of community engagement (β = 0.14, 95%CI = −0.14, 0.41).ConclusionThe current study did not find clear evidence for social support or community engagement mediating the relationship between neighbourhood income inequality and maternal mental health. Future investigations should employ a broader longitudinal approach to capture changes in income inequality, potential mediators, and mental health symptomatology over time.  相似文献   
4.
目的:探讨脑出血对酵母沉默信息调节因子2(Sirt2)和炎症的影响。方法:将胶原酶Ⅳ注入SD大鼠右侧 纹状体中建立脑出血模型,通过免疫印迹和ELISA 等方法测定大鼠脑出血后48 h 的Sirt2 的表达及炎症变化。利 用Hemin 诱导PC12 细胞损伤模拟体外脑出血模型,并检测Sirt2 及炎症变化;采用短发夹RNA(shRNA)-Sirt2 沉 默Sirt2 在PC12 细胞中的表达及对炎症的影响。结果:手术后48 h 脑出血行为学评分最低。脑出血组Sirt2 的表达 显著高于假手术组。脑出血组IL-6、IL-1β 表达显著升高。结论:脑出血可以促进Sirt2 的表达和炎症反应,降低 Sirt2 的表达可减缓炎症反应。 关键词 脑出血;沉默信息调节  相似文献   
5.
《Vaccine》2020,38(1):20-28
During the last few decades, maternal immunization as a strategy to protect young infants from infectious diseases has been increasingly recommended, yet some issues have emerged. Studies have shown that for several vaccines, such as live attenuated, toxoid and conjugated vaccines, high maternal antibody titers inhibit the infant’s humoral immune response after infant vaccination. However, it is not clear whether this decreased antibody titer has any clinical impact on the infant’s protection, as the cellular immune responses are often equally important in providing disease protection and may therefore compensate for diminished antibody levels. Reports describing the effect of maternal antibodies on the cellular immune response after infant vaccination are scarce, probably because such studies are expensive, labor intensive and utilize poorly standardized laboratory techniques. Therefore, this review aims to shed light on what is currently known about the cellular immune responses after infant vaccination in the presence of high (maternal) antibody titers both in animal and human studies. Overall, the findings suggest that maternally derived antibodies do not interfere with the cellular immune responses after infant vaccination. However, more research in humans is clearly needed, as most data originate from animal studies.  相似文献   
6.
7.
《Vaccine》2019,37(21):2814-2820
BackgroundVaccinations in pregnancy are recommended for the potential benefits of preventing severe pertussis disease in newborns and for preventing the impact of influenza on the pregnant woman, her foetus in utero and, the newborn in the first six months of life. Published data in Australia suggested that coverage rates were sub-optimal so the reasons for this were reviewed.MethodsA cross-sectional survey of 1014 postnatal women, aged 18 years and older, who had given birth in the previous six months was undertaken on the Gold Coast in Queensland, Australia. Participants completed a brief questionnaire on provided smart tablets at public vaccination clinics or with a researcher by phone or via an on-line link.ResultsJust over 85% of survey respondents received a pertussis booster with many of those not receiving vaccine having had it in a recent pregnancy. Only 36.7% of respondents had an influenza vaccine in pregnancy with key barriers being belief in influenza vaccine, seasonality of parturition and a lack of recommendation from the attending obstetric carers.DiscussionWhile maternal pertussis vaccine programs are a success, work needs to be done to improve the public perception of the risk benefit equation surrounding influenza vaccine in general, and particularly its use in pregnancy. Research is required into approaches to altering practitioner attitudes as well as how to alter public perceptions.  相似文献   
8.
BackgroundFrom birth to young adulthood, health and development of young people are strongly linked to their living situation, including their family’s socioeconomic position (SEP) and living environment. The impact of regional characteristics on development in early childhood beyond family SEP has been rarely investigated. This study aimed to identify regional predictors of global developmental delay at school entry taking family SEP into consideration.MethodWe used representative, population-based data from mandatory school entry examinations of the German federal state of Brandenburg in 2018/2019 with n=22,801 preschool children. By applying binary multilevel models, we hierarchically analyzed the effect of regional deprivation defined by the German Index of Socioeconomic Deprivation (GISD) and rurality operationalized as inverted population density of the children’s school district on global developmental delay (GDD) while adjusting for family SEP (low, medium and high).ResultsFamily SEP was significantly and strongly linked to GDD. Children with the highest family SEP showed a lower odds for GDD compared to a medium SEP (female: OR=4.26, male: OR=3.46) and low SEP (female: OR=16.58, male: OR=12.79). Furthermore, we discovered a smaller, but additional and independent effect of regional socioeconomic deprivation on GDD, with a higher odds for children from a more deprived school district (female: OR=1.35, male: OR=1.20). However, rurality did not show a significant link to GDD in preschool children beyond family SEP and regional deprivation.ConclusionFamily SEP and regional deprivation are risk factors for child development and of particular interest to promote health of children in early childhood and over the life course.  相似文献   
9.
Background/purposePertussis incidence markedly decreased due to universal vaccination, but outbreaks had been noted worldwide in recent decade. This study was conducted to know the epidemiology of pertussis and its impact on infants in Taiwan.MethodsEpidemiologic parameters for confirmed pertussis cases were collected from the Taiwan Centers for Disease Control. The incidence of each age group over years was calculated using population data. We also did retrospective reviews of laboratory-confirmed pertussis cases in NTUH to analyze clinical characteristics and disease severity.ResultsA total of 668 confirmed pertussis cases were obtained from the Taiwan CDC open database between 2003 and 2017. There was higher incidence during the period 2009–2015, with a mean incidence of 0.27 cases per 100,000 population, about 2-fold increase compared with mean incidence of 0.12 cases per 100,000 population during the period 2003–2008. Infants accounted for the highest proportion of all cases (49.8%), with mean incidence of 16.1 cases per 100,000 people per year during 2009–2015, and a trend of increase was found from 2003 to 2015. In NTUH, a total of 17 laboratory-confirmed pertussis cases were diagnosed during 2012–2016, and 14 cases were young infants. Among them, 9 infants had been admitted to intensive care unit and 2 infant needed invasive ventilator support.ConclusionThere was a resurgence of pertussis during 2009–2015 and it had significant impact on infants. Young infants with pertussis may be severe and need intensive care, so preventive strategy may be advocated for them.  相似文献   
10.
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