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   21591篇
  免费   2202篇
  国内免费   1243篇
耳鼻咽喉   198篇
儿科学   276篇
妇产科学   417篇
基础医学   1987篇
口腔科学   433篇
临床医学   2855篇
内科学   2796篇
皮肤病学   251篇
神经病学   952篇
特种医学   691篇
外国民族医学   8篇
外科学   1428篇
综合类   4457篇
现状与发展   10篇
一般理论   1篇
预防医学   1957篇
眼科学   549篇
药学   2734篇
  16篇
中国医学   1711篇
肿瘤学   1309篇
  2024年   18篇
  2023年   300篇
  2022年   557篇
  2021年   933篇
  2020年   810篇
  2019年   592篇
  2018年   630篇
  2017年   684篇
  2016年   614篇
  2015年   971篇
  2014年   1226篇
  2013年   1280篇
  2012年   1834篇
  2011年   1923篇
  2010年   1467篇
  2009年   1242篇
  2008年   1476篇
  2007年   1365篇
  2006年   1312篇
  2005年   1116篇
  2004年   803篇
  2003年   716篇
  2002年   667篇
  2001年   500篇
  2000年   409篇
  1999年   310篇
  1998年   168篇
  1997年   186篇
  1996年   135篇
  1995年   140篇
  1994年   101篇
  1993年   67篇
  1992年   88篇
  1991年   78篇
  1990年   63篇
  1989年   53篇
  1988年   47篇
  1987年   34篇
  1986年   35篇
  1985年   17篇
  1984年   11篇
  1983年   7篇
  1982年   7篇
  1981年   7篇
  1977年   5篇
  1976年   3篇
  1975年   3篇
  1974年   3篇
  1973年   4篇
  1972年   4篇
排序方式: 共有10000条查询结果,搜索用时 23 毫秒
1.
2.
Background: Considering the poor prognosis of non-small cell lung cancer (NSCLC), the objective of this study was to examine the potential of plasma-derived vesicles as a source of lung cancer-specific proteins. Extracellular vesicle (EV) cargos are specific to the source cells, hence they have the potential of being a source of cancer-specific proteins.  Methods: The proteins differently expressed in cancer were determined and derived from EVs isolated from the plasma of NSCLC patients at the National Lung Hospital. To this end, purification was done using gel filtration chromatography and ultracentrifugation. In addition, nano liquid chromatography mass spectrometry (LC–MS/MS) was used for analyzing. Results: Fifty-seven EV-derived proteins related to NSCLC were highlighted in this research. Some of them have not been addressed before, such as EEF1A1 (elongation factor 1-α1), KPNB1 (Importin subunit beta 1), SRC (proto-oncogene tyrosine-protein kinase) and ACTC1 (actin, alpha cardiac muscle 1). This list was further confirmed through a comparison with ExoCarta and Vesiclepedia. Conclusion: This study is the first work to show the involvement of several novel proteins of small EV (EEF1A1, KPNB1, SRC, and ACTC1) in the progression of NSCLC. The results suggested that they could serve as novel biomarkers for non-small cell lung cancer in the future.  相似文献   
3.
4.
5.
IntroductionThe coronavirus disease 2019 (COVID-19) pandemic was expected to have a negative impact on organ donation. With the differences in health care systems and lockdown policies in various regions, the pandemic's effect on organ donation and transplant service may vary. Most of the deceased donor organ referrals in our hospital came from non–intensive care units (ICUs). The objective of this study is to report our experience and quantify the effects of the COVID-19 pandemic on deceased donor organ donation in our center.MethodsThis was a retrospective observational study comparing the deceased donor organ donation activity during the period January 23 to November 30, 2020 with the same period in 2018 in Queen Elizabeth Hospital, Hong Kong.ResultsThere was a 26.9% reduction in deceased donor organ donor referral in 2020 compared with 2018. No significant difference in the proportion of referrals from ICU or non-ICU areas between the 2 time periods was observed. The brain death confirmation rate was significantly higher in 2020 (40.8% vs 20.2%, P = .003). Nine patients had family consent for organ donation in 2020 (vs 7 patients in the same period in 2018). There were no significant differences in consent rate and number of recovered organs between the 2 periods.ConclusionsWith effective measures to limit the spread of COVID-19 in a community, it is possible to support the needs of both patients with COVID-19 and deceased donor organ donation services.  相似文献   
6.
Background:Chronic non-atrophic gastritis is the most common type of chronic gastritis. Even if treated with current standard pharmacotherapy, the efficacy is not very satisfactory due to many factors. Traditional Chinese Medicine decoctions are increasingly used in the treatment of chronic gastritis, and many studies have shown that Xiangsha Liujunzi decoction is effective and safe in the treatment of chronic non-atrophic gastritis. However, it is controversy if Xiangsha Liujunzi decoction can provide an evidence-based clinical efficacy and safety in the treatment of chronic non-atrophic gastritis.Methods:We will go through 8 databases, and conduct a systematic review of Xiangsha Liujunzi decoction and health-related outcomes in chronic non-atrophic gastritis patients according to the Preferred Reporting Items for Systematic Reviews. The primary objective is to assess the impact of Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines on clinical outcomes relevant to chronic non-atrophic gastritis patients, such as clinical effective rate,Helicobacter pylori eradication rate, efficacy under endoscopy, 1-year recurrent rate, and number of reported adverse events. Cochrane Risk Assessment Tool will be used to assess the quality of eligible studies according to the Cochrane handbook.Results:The results of this systematic review will provide a synthesis of current evidence of Xiangsha Liujunzi decoction and we have a specific opportunity to determine the efficacy and safety of it.Conclusion:This study will explore whether or not Xiangsha Liujunzi decoction can be used as one of the complementary and alternative therapies in the treatment of chronic non-atrophic gastritis.Registration number:Identifier: DOI 10.17605/OSF.IO/TX27U (https://osf.io/tx27u/).  相似文献   
7.
目的了解某三甲综合医院患者门诊预约精准性及其影响因素,比较正确预约与错误预约患者在预约可及性因素上的差异,寻找提高门诊预约精准性的干预点。方法采用现场调查法,于2021年6月14—21日在四川省成都市某三甲综合医院对70例门诊患者进行面访调查。结果门诊预约精准性低,错误预约患者占36.75%。单因素分析显示,预约精准性正向影响因素包括医疗保险保障度(P=0.004)、线下信息可及度(P=0.049)以及医务人员推荐依从度(P<0.001),负向影响因素包括网络信息依从度(P=0.012)、传统媒体信息可及度(P=0.024)以及自媒体推荐依从度(P<0.001);二分类非条件logistic回归分析显示,预约精准性与听从医务人员推荐正相关(P=0.002),与听从自媒体推荐负相关(P=0.014)。结论医疗机构需要加强宣传力度、丰富宣传内容,提高患者就诊的可及性;建议加强网络及传统媒体虚假医疗信息整治力度能改变门诊患者预约精准性低的现况。  相似文献   
8.
目的 Dof(DNA binding with one finger)家族是高等植物中特有的一类转录因子家族,参与植物中光、激素、非生物胁迫等多种胁迫响应调控。本研究基于全基因组数据对黄花蒿Dof(AaDof)转录因子家族进行鉴定及表达模式分析,探究Dof家族基因在青蒿素合成调控中的作用。方法 经PFAM数据库鉴定获得AaDof序列,通过生物信息学软件分析其理化性质、亚细胞定位、基因结构、蛋白保守结构以及启动子序列结合元件等,并基于赤霉素(Gibberellic acid, GA)、紫外线B(UV-B)及二者协同胁迫下黄花蒿转录组数据对其表达模式进行分析。结果 本研究从全基因组水平共鉴定出51个AaDof基因,均含有保守的C2-C2单锌指结构,依据系统发育分析分为8个亚族,同一亚族内基因结构与蛋白保守结构域相对保守。亚细胞定位预测显示12个AaDof蛋白定位在细胞外,其余均定位在细胞核。启动子元件分析发现AaDof家族基因启动子区富含光、激素等多种响应元件。对AaDof在GA、UV-B和GA+UV-B处理下的表达模式分析发现,AaDof基因对GA胁迫处理响应较弱,仅有少量基因敏感,其表达主要受到UV-B胁迫影响。C1及C2.1亚族大部分基因在UV-B胁迫下上调表达,而A亚族大部分基因在UV-B胁迫下下调表达。qRT-PCR验证表明AaDof1AaDof17AaDof44在GA和UV-B处理下表达量显著上调,推测其可能通过参与GA和UV-B调控网络,正向调控青蒿素生物合成。结论 本研究系统鉴定了黄花蒿AaDof家族基因并筛选了3个可能正向调控青蒿素生物合成的候选AaDof基因,为黄花蒿Dof家族基因功能研究及其在青蒿素生物合成中的调控机制解析奠定基础。  相似文献   
9.
背景 结核病是导致人免疫缺陷病毒/获得性免疫缺陷综合征(HIV/AIDS)患者死亡的首要原因,而HIV感染也是导致结核潜伏感染(LTBI)发展为结核病的主要危险因素。因此,对HIV/AIDS患者进行LTBI筛查和治疗是预防该类人群结核病的发生从而减少其死亡的重要举措。 目的 对宁夏回族自治区银川市市区内HIV/AIDS患者进行LTBI筛查,并分析其影响因素,识别高危人群,为HIV/AIDS患者结核病的预防性治疗提供科学依据。 方法 选取2021年3—8月于宁夏回族自治区银川市市区内定点管理单位治疗的546例HIV/AIDS患者为研究对象。通过现场问卷调查及查阅患者管理档案的方式收集HIV/AIDS患者的一般资料,其中一般人口学特征包括性别、年龄、民族、学历、婚姻状况、家庭人均年收入、职业类型、体质指数(BMI)、吸烟情况、饮酒情况等;临床资料包括慢性病患病情况、与结核病患者密切接触情况、HIV/AIDS确诊时长、抗病毒治疗时长、合并其他感染情况、近期CD4+ T淋巴细胞计数(CD4)等。通过结核菌素皮肤试验(TST)对研究对象进行LTBI筛查,根据TST结果将546例HIV/AIDS患者分为非LTBI组(TST阴性413例)和LTBI组(TST阳性133例)。比较两组患者的一般资料,采用多因素Logistic回归分析探讨HIV/AIDS患者发生LTBI的影响因素,并利用R软件建立限制性立方样条模型拟合CD4与LTBI风险之间的量效关系。 结果 银川市市区内HIV/AIDS患者的TST阳性率为24.4%。已婚〔OR=0.544,95%CI(0.321,0.922),P<0.05〕是HIV/AIDS患者发生LTBI的保护因素;吸烟〔OR=1.919,95%CI(1.213,3.037),P<0.05〕、与结核病患者有过密切接触〔OR=11.100,95%CI(2.889,42.648),P<0.05〕是HIV/AIDS患者发生LTBI的危险因素。限制性立方样条模型拟合结果显示,HIV/AIDS患者的CD4与LTBI风险呈近似"n"形的非线性关系(非线性检验χ2=29.080,P<0.001)。 结论 应重点关注HIV/AIDS患者中未婚、吸烟、与结核病患者有过密切接触人群LTBI的发生情况,并及时进行预防性治疗;对于CD4较低的患者,建议采用多种方法进行LTBI筛查。  相似文献   
10.

Background

Pregnant women are at increased risk of hospitalization, serious complications, poor pregnancy outcomes, and mortality from influenza. Prior research suggests that there are racial/ethnic disparities in vaccination coverage and that a healthcare provider vaccination recommendation is associated with significantly higher vaccine uptake than without such a recommendation. The purpose of this study is to examine racial/ethnic disparities in healthcare providers’ recommendations for pregnant women to receive the influenza vaccine and in vaccine uptake.

Methods

This cross-sectional population-based study analyzed data from the Centers for Disease Control and Prevention’s Pregnancy Risk Assessment Monitoring System (PRAMS) during 2012–2015 (n?=?130161). Both healthcare provider recommendation and vaccine uptake were assessed dichotomously. Logistic regression was conducted to ascertain adjusted odds ratios and 95% confidence intervals, controlling for maternal age, marital status, education, prenatal care utilization, and smoking status.

Results

Influenza vaccine uptake during pregnancy ranged from 39.1% among non-Hispanic (NH) Black women to 55.4% among NH Asian women. In the adjusted analysis, NH Black and NH Asian women had 19% (95% CI 0.75–0.86) and 34% (95% CI 0.61–0.72) decreased odds of receiving a provider recommendation for influenza vaccine during pregnancy, respectively, compared to NH White women. For influenza vaccine uptake, NH Black women were 30% less likely (95% CI 0.65–0.74) to receive influenza vaccine during pregnancy compared to NH White women.

Conclusions

Our findings indicate that there are racial/ethnic disparities in healthcare provider recommendation and influenza vaccine uptake among pregnant women in the United States. Targeted efforts toward providers and interventions focusing on pregnant women may be warranted to reduce the disparity.  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