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   14339篇
  免费   2178篇
  国内免费   297篇
耳鼻咽喉   9篇
儿科学   204篇
妇产科学   185篇
基础医学   1484篇
口腔科学   56篇
临床医学   1199篇
内科学   3739篇
皮肤病学   81篇
神经病学   369篇
特种医学   418篇
外国民族医学   1篇
外科学   409篇
综合类   930篇
现状与发展   6篇
预防医学   6358篇
眼科学   72篇
药学   722篇
  4篇
中国医学   89篇
肿瘤学   479篇
  2024年   51篇
  2023年   720篇
  2022年   996篇
  2021年   1042篇
  2020年   1440篇
  2019年   884篇
  2018年   863篇
  2017年   742篇
  2016年   898篇
  2015年   1078篇
  2014年   1229篇
  2013年   934篇
  2012年   955篇
  2011年   781篇
  2010年   853篇
  2009年   754篇
  2008年   361篇
  2007年   428篇
  2006年   368篇
  2005年   254篇
  2004年   204篇
  2003年   199篇
  2002年   129篇
  2001年   78篇
  2000年   57篇
  1999年   93篇
  1998年   74篇
  1997年   60篇
  1996年   80篇
  1995年   49篇
  1994年   31篇
  1993年   21篇
  1992年   19篇
  1991年   14篇
  1990年   10篇
  1989年   12篇
  1988年   19篇
  1987年   18篇
  1986年   14篇
  1984年   1篇
  1968年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
目的:研究分析放射治疗对乳腺癌患者免疫系统相关指标的影响。方法:选取在医院就诊的6例病理诊断为乳腺癌Ⅱ~Ⅲ期患者,将所有患者放射治疗前(0 Gy)静脉血样本定义为对照组、放射治疗20 Gy和50 Gy照射后静脉血样本分别定义为20 Gy组和50 Gy组,于放射治疗10次后、25次后采集不同放射治疗累积剂量24 h后静脉血8 ml;采用流式细胞术检测所有受检者不同剂量放射治疗后外周血淋巴细胞亚群百分数、外周血淋巴细胞凋亡及细胞周期的改变;实时荧光定量聚合酶链反应(q RT-PCR)法检测外周血淋巴细胞微小核糖核酸(miRNA)的改变。结果:乳腺癌患者20 Gy组和50 Gy组照射后与对照组比较,淋巴细胞亚群CD3+、CD4+/CD8-和CD4+/CD8+表达水平均呈下调趋势,CD4-/CD8+呈上升趋势,但差异均无统计学意义;20 Gy组T细胞抗原受体(TCR)/CD3明显下调,与对照组比较差异有统计学意义(Z=-2.008,P<0.05),50 Gy组TCR/CD3有所回升,但差异无统计学意义。不同剂量的两组照射后乳腺癌患者mi RNA-150、mi RNA-210表达水平随剂量增加呈降低趋势,50 Gy组表达水平明显降低,与对照组相比差异有统计学意义(Z=-2.242,Z=-2.402;P<0.05)。结论:放射治疗未引起乳腺癌患者明显的免疫功能抑制,可能是通过改变mi RNA-150、mi RNA-210的通路而抑制肿瘤的生长。  相似文献   
112.
目的 了解2016-2017年江苏省儿童青少年膳食及血清锌状况,探索其与营养相关心血管疾病代谢危险因素之间可能存在的关系。 方法 采用多阶段分层随机抽样的方法,2016-2017年从江苏省12个监测点抽取1 251名6~17岁儿童青少年进行体格测量(身高、体重、腰围)、血液生化检验(血清锌、空腹血糖、血脂),并采用连续3 d 24 h膳食回顾法对其进行膳食调查。统计学方法采用Pearson χ2检验、Kruskal-Wallis检验及线性回归分析。 结果 最终有1 122名6~17岁儿童青少年纳入本研究。其膳食锌摄入低于平均需要量(EAR)比例为39.39%,其中13~17岁年龄组、一般农村的被调查对象比例较高,分别为56.7%和54.8%;血清锌水平低于参考值的比例较低,为0.5%,但在不同性别、地区间存在差异,其中男性、大城市儿童青少年血清锌水平较高。线性回归分析结果表明,膳食锌与血清锌无线性关系;膳食锌与高密度脂蛋白呈正相关(β=0.072,95%CI: 0.034~0.111,P<0.001);血清锌与空腹血糖呈负相关(β=-0.506,95%CI:-0.575~-0.437,P<0.001)。 结论 江苏省儿童青少年存在膳食锌摄入不足风险的比例依然较高,充足的膳食锌摄入及较高的血清锌水平与儿童青少年良好的代谢状况有关。  相似文献   
113.
In April 2017, surveillance detected a surge in severe acute respiratory infections (SARI) in Bangladesh. We collected specimens from SARI patients and asymptomatic controls for analysis with multipathogen diagnostic tests. Influenza A(H1N1)pdm09 was associated with the SARI epidemic, suggesting that introducing vaccines and empiric antiviral drugs could be beneficial.  相似文献   
114.
To limit the spread of severe acute respiratory syndrome coronavirus 2, the government of China has been monitoring infected travelers and minimizing cold-chain contamination. However, other factors might contribute to recurring outbreaks. We analyze the role of undocumented migrants as potential transmitters of severe acute respiratory syndrome coronavirus 2 in China.  相似文献   
115.
BackgroundTo support the early identification of childhood obesity, Head Start (HS) implemented a body mass index screening program. This program provides opportunities for HS to communicate with families about children's weight status. Limited research is available describing the methods used to communicate this information.ObjectiveExplore common experiences of HS health/nutrition managers (HNM) when communicating information to families about children's weight status.Study Design, Settings, and ParticipantsTwenty-eight in-depth telephone interviews with HNM across North Carolina (n = 15) and Ohio (n = 13).Study Design/AnalysisPhenomenology guided the study design and analysis. The themes focused on HNM's lived experiences with their body mass index screening program. Interviews were recorded and transcribed verbatim.ResultsFour emergent themes identified: (1) strategies for communicating weight status to families; (2) family response to communication strategies; (3) educational, staff support, and counseling opportunities for families; and (4) challenges engaging families in childhood obesity prevention efforts.Conclusions and ImplicationsHead Start programs acknowledged the importance of communicating children's weight status; however, there are inconsistencies in methods used and information communicated across programs. Head Start programs have community partners who support obesity prevention efforts; however, these partnerships may be underused. More research is needed to explore effective and sensitive communication methods for HS families regarding children's weight status.  相似文献   
116.
ObjectivesHospitalized patients with dementia transitioning to post-acute care may be particularly vulnerable to changes in post-acute care utilization driven by payment reforms; however, use of post-acute care in this population is incompletely understood. We sought to describe post-acute care utilization in skilled nursing facilities (SNFs) and from home health (HH) agencies among Medicare beneficiaries with a diagnosis of dementia.DesignRetrospective, observational study using 100% sample of Medicare beneficiaries from 2013 to 2016.Setting and ParticipantsWe identified hospitalizations and diagnoses using Medicare Provider Analysis and Review (MedPAR), SNF stays using the Minimum Data Set, HH episodes using the Outcome and Assessment Information Set, and dementia diagnoses using the Medicare Beneficiary Summary File Chronic Conditions segment.MethodsWe calculated overall utilization and trends in post-acute care use over time, stratified by dementia diagnosis, type of post-acute care (SNF vs HH), and payer (fee-for-service vs Medicare Advantage).ResultsOf the 9,762,208 Medicare fee-for-service beneficiaries who received post-acute care from 2013 to 2016, 3,155,560 (32.3%) carried a diagnosis of dementia. Rates of post-acute care use were similar over time. More beneficiaries with a diagnosis of dementia received post-acute care (44.2% vs 27.7%) and proportionally more SNF care (71.7% vs 49.6%). Overall use and trends were similar in the Medicare Advantage population.Conclusions and ImplicationsOne-third of all fee-for-service Medicare beneficiaries receiving post-acute care have a diagnosis of dementia, and more than 7 in 10 receive this care in an SNF. These findings serve as a foundation for needed evaluations of how best to meet the post-hospital needs of older adults with dementia.  相似文献   
117.
近年来中国职业卫生与职业病研究取得了长足的发展,以职业暴露人群为研究中心,针对职业病的病因、发病机制、人群易感性生物标志物以及风险评估等方面开展了大量的研究,填补了中国甚至世界范围内诸多职业卫生与职业病方面的空缺,具有重要的公共卫生意义。目前中国处于高速发展阶段,大批新兴的、创新的技术正应用于各个领域,推动着中国的产业结构、生产方式和生产技术发生巨大变革,新兴领域的高速发展对职业卫生提出了新的挑战,表现为传统的职业性有害因素带来的职业卫生问题逐渐减少,新的问题不断出现。职业卫生和职业医学也迫切需要将医学科学的新理念、新技术应用于本学科,建立新型健康风险评价体系,进而满足职业人群健康监护和职业病诊断治疗的需求。  相似文献   
118.
  目的  分析青海省学生肺结核患者治疗转归的现况及其影响因素,为完善学校肺结核防控策略提供依据。  方法  收集青海省2015—2019年学生肺结核流行病学信息并分析描述其治疗转归现况,通过构建二元logistic回归分析模型分析影响学生肺结核患者治疗转归的相关因素。  结果  学生肺结核患者治疗成功率为89.08%,呈逐年上升趋势(χ2 =120.630, P < 0.001)。不同市(州)学生肺结核患者治疗成功率差异有统计学意义(χ2 =67.866, P < 0.001)。多因素分析结果显示少数民族、发生就诊延迟、复治和非全程督导管理是影响治疗转归的危险因素。  结论  学生肺结核患者治疗成功率较高,但受多种因素影响,应加强关注、采取有效措施进一步提升。  相似文献   
119.
BackgroundKnowledge of adverse childhood events (ACEs), the associated access to healthcare and unmet needs among children and youth with special health care needs (CYSHCN) is limited.ObjectivesOur objectives were to compare the likelihood of CYSHCN versus non-CYSHCN experiencing one or more ACEs and document differences in receipt of recommended and needed health care among CYSHCN with and without ACEs.MethodsWe combined two years of data from the 2016 and 2017 National Survey of Children's Health (N = 71,181), providing a sample of 16,304 CYSHCN. Our primary outcome measures included eight adverse childhood events, compared to singular and aggregated ACEs among non-CYSHCN. We calculated associations between ACEs and secondary outcome measures for six components of well-functioning systems of care and unmet need for different types of health care using bivariate and multivariate analyses.ResultsCYSHCN were more likely to have each of the ACEs measured and were likelier to experience aggregated levels of ACEs compared to non-CYSHCN. The likelihood of CYSHCN having a medical home with family-centered and coordinated care decreased with increased ACEs, while one or more ACES increased the likelihood of having unmet needs for mental health care.ConclusionThe findings of the current study extend our understanding of the additional adverse event burden associated with special health care needs status, the accompanying limitations in access to family-centered and coordinated care in a medical home and unmet need for mental health care, indicating that much work remains in establishing appropriate care systems for this very vulnerable population.  相似文献   
120.
BackgroundChildren with disabilities present with high obesity rates.ObjectiveThis study explored the parental experience of adopting healthy lifestyle choices, for children with disabilities, who received dietetic weight management advice.MethodsSemi-structured qualitative interviews were carried out with eight parents/carers in their own homes or healthcare setting in an inner London locality, or by telephone. Data was analyzed using an interpretative phenomenological analysis (IPA) approach.ResultsFive superordinate themes emerged: 1. Strategies to promote healthy lifestyles: encouraging physical activity, limiting access to food and taking a gradual approach to making lifestyle changes. 2. Challenges to adopting healthy lifestyles: selective eating patterns, the high cost of healthy foods and parental/carer lack of time. 3. The role of healthcare professionals (HCPs): revealed that not all parents/carers received advice or support, prior to dietetic referral, when managing their child's weight. Feeling reassured by HCPs was valued. Parents/carers reported a positive experience of seeing the dietitian, as they appreciated receiving practical and individualized advice. 4. Support needs: family support and support from families with children with disabilities was explored. 5. Parent/carer wellbeing: such as stress was found to have a detrimental impact on parents making healthy lifestyle changes.ConclusionsAdopting a healthy lifestyle involved a variety of strategies and challenges, some of which are specific to this population group and should be considered by HCPs, when having weight-related discussions and offering advice. Parental/carer support needs and wellbeing should also be taken into consideration when planning weight management services for this population group.  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