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   26269篇
  免费   3290篇
  国内免费   960篇
耳鼻咽喉   240篇
儿科学   600篇
妇产科学   416篇
基础医学   3599篇
口腔科学   722篇
临床医学   2709篇
内科学   4434篇
皮肤病学   284篇
神经病学   1728篇
特种医学   1053篇
外科学   4774篇
综合类   3206篇
一般理论   5篇
预防医学   2032篇
眼科学   375篇
药学   1792篇
  8篇
中国医学   843篇
肿瘤学   1699篇
  2024年   84篇
  2023年   478篇
  2022年   791篇
  2021年   903篇
  2020年   907篇
  2019年   1374篇
  2018年   1912篇
  2017年   849篇
  2016年   782篇
  2015年   817篇
  2014年   1671篇
  2013年   1630篇
  2012年   1411篇
  2011年   1660篇
  2010年   1340篇
  2009年   1376篇
  2008年   1424篇
  2007年   1388篇
  2006年   1166篇
  2005年   1231篇
  2004年   894篇
  2003年   710篇
  2002年   628篇
  2001年   444篇
  2000年   568篇
  1999年   508篇
  1998年   454篇
  1997年   315篇
  1996年   276篇
  1995年   215篇
  1994年   263篇
  1993年   261篇
  1992年   332篇
  1991年   135篇
  1990年   206篇
  1989年   80篇
  1988年   168篇
  1987年   113篇
  1986年   103篇
  1985年   107篇
  1984年   101篇
  1983年   51篇
  1982年   84篇
  1981年   32篇
  1980年   47篇
  1979年   36篇
  1978年   20篇
  1977年   33篇
  1976年   40篇
  1974年   26篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
目的 观察结肠癌HCT116细胞健脾消癌方的条件培养液对HUVEC细胞管腔形成的影响,从PI3K/Akt生物轴调控角度探讨其作用机制。方法 培养HCT116细胞,细胞设3组:对照组,健脾消癌方组(加入15%健脾消癌方含药血清)及人参皂苷Rg3组;制备HCT116细胞健脾消癌方条件培养液(分组及制备方法见实验方法),用条件培养液干预HUVEC(脐静脉内皮细胞,Human Umbilical Vein Endothelial Cells),Matrigel基质胶法检测HCT116细胞健脾消癌方条件培养液对HUVEC小管形成的影响。随后采用蛋白免疫印迹法(Western blot)检测各组HCT116细胞磷脂酰肌醇3-激酶(PI3K)、蛋白激酶B(Akt)、p-Akt、VEGF(血管内皮生长因子,Vascular endothelial growth factor)蛋白表达。最后在结肠癌HCT116荷瘤小鼠中验证健脾消癌方对肿瘤生长速度的影响,并经瘤组织VEGF蛋白表达、CD31免疫组化染色检测肿瘤内血管生成情况。结果 模型组HUVEC细胞管腔形成较空白血清组显著增加(P<0.05);健脾消癌方组及人参皂苷Rg3组较模型组HUVEC细胞管腔形成显著减少(P<0.01)。p-Akt和VEGF蛋白表达水平模型组高于空白血清组(P<0.05),健脾消癌方组及人参皂苷Rg3组显著低于模型组(P<0.01);PI3K、Akt蛋白表达量组间差异无统计学意义。与对照组比较,模型组荷瘤小鼠肿瘤体积显著性增大,瘤组织内VEGF表达、CD31阳性面积显著性增加,差异有统计学意义(P<0.05);与模型组比较,健脾消癌方组及人参皂苷Rg3组荷瘤小鼠肿瘤体积显著减小,瘤组织内VEGF表达、CD31阳性面积降低,差异有统计学意义(P<0.05)。结论 健脾消癌方可抑制肿瘤的血管生成和生长,其作用机制可能与PI3K/Akt生物轴调控VEGF表达有关。  相似文献   
2.
3.
4.
5.
6.
BackgroundWhile hyperglycemia has a key role in the pathogenesis of microvascular complications of diabetes, it is just one of the many factors contributing to macrovascular damage. The aim of the present study is to investigate the link between serum pentosidine and sRAGE levels and vascular complications in patients with prediabetes compared to normal glucose tolerance controls with obesity.MethodsIn this study were included 76 patients with mean age 50.7 ± 10.7 years, divided into two age and BMI-matched groups – group 1 with obesity without glycemic disturbances (n = 38) and group 2 with obesity and prediabetes (n = 38).ResultsThere was no significant difference in pentosidine and sRAGE levels between patients with obesity and prediabetes. Patients with hypertension had lower levels of sRAGE compared to nonhypertensive subjects. sRAGE showed a weak negative correlation to blood glucose on 60th min of OGTT and HOMA index. There was no correlation between sRAGE and pentosidine levels and the markers of micro- and macrovascular complications. There was no difference in sRAGE and pentosidine levels between patients with and without endothelial dysfunction.Conclusions: sRAGE and pentosidine levels are similar in patients with obesity with and without prediabetes and do not correlate to the markers of micro- and macrovascular complications.  相似文献   
7.
BackgroundDual antiplatelet therapy (DAPT) is the cornerstone treatment of acute myocardial infarction (AMI).ObjectiveThe present study aimed to investigate the efficacy and safety of triple antiplatelet therapy (TAPT) in elderly female patients with diabetes and ST segment elevation myocardial infarction (STEMI), who had undergone percutaneous coronary intervention (PCI).MethodsWe designed a randomized, single-blind study. Control group A (97 elderly male patients with diabetes and STEMI, whose CRUSADE scores were < 30) received aspirin, ticagrelor, and tirofiban. A total of 162 elderly female patients with diabetes and STEMI were randomly divided into two groups according to CRUSADE score. Group B (69 patients with CRUSADE score > 31) received aspirin and ticagrelor. Group C (93 patients with CRUSADE score < 30) received aspirin, ticagrelor and tirofiban. P values < 0.05 were considered statistically significant.ResultsCompared to the findings in group A, post-PCI Thrombolysis in Myocardial Infarction (TIMI) grade 3 blood flow and TIMI myocardial perfusion grade 3 were significantly less prevalent in group B (p < 0.05). When compared to groups A and C, the incidence of major adverse complications was significantly higher in group B (p < 0.05).ConclusionTAPT could effectively reduce the incidence of major complications in elderly female patients with diabetes and STEMI. However, close attention should be paid to hemorrhage in patients receiving TAPT. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)  相似文献   
8.
《Vaccine》2020,38(45):7118-7128
IntroductionToward the Global Vaccine Action Plan 2020 goal, almost 90% of countries have established a National Immunization Technical Advisory Group (NITAG). However, little is known about NITAG's contributions to governance.MethodsIn 2017–2018, a two-step, qualitative retrospective study was conducted. Jordan (JO), Argentina (AR), and South Africa (SA) were selected owing to government-financed NITAGs from middle-income countries (MICs), geographic diversity, and a vaccine introduction with NITAG support. Country case studies were developed, collecting data through desk review and face-to-face key informant interviews (KIIs) from Ministry of Health (MoH) and NITAG. Case studies were analyzed together, to assess governance applying the European Observatory on Health Systems and Policies framework focusing on transparency, accountability, participation, integrity, and policy capacity (TAPIC).ResultsDocument review and 53 KII (22 AR, 20 SA, 11 JO) showed NITAGs played a pivotal role as advisors promoting a culture of evidence-informed policies. NITAGs strengthened governance, although practices varied among countries. Meetings were conducted behind-closed-doors, participation restricted to members, only in one country agendas, and recommendations were public (AR). To increase participation, policy capacity, and transparency, countries considered adding experts in communications, advocacy, and economics. AR and SA contemplated including community members. NITAGs functioned autonomously from the government, with no established internal or external monitoring or supervision. NITAG meeting minutes allowed the review of integrity, adherence to terms of reference, standard operating procedures, and conflict of interest (CoI). For the most part, NITAGs abided by their mandates. Significant issues were related to the level of MoH support and oversight of CoI declaration and documentation.ConclusionsSystematically implementing governance approaches could improve processes, better tailor policies, and implementation. The long-term survival and resilience of NITAGs in these countries showed they play a significant role in strengthening governance. Lessons learned could be useful to those promoting country-driven evidence-informed decision-making.  相似文献   
9.
10.
The Yakima Valley Farm Workers Clinic (YVFWC) is one of the largest community health centers in the country with clinics throughout south-central Washington and northern Oregon. Its dental program consists of 14 dental clinics providing general and specialty services to the low-income populations it serves. Modeling itself after the YVFWC medical managed care program; the Dental program recently added value-based metrics to its dental practice after Oregon offered a value-based dental reimbursement plan in 2019. This is the first-step YVFWC's dental program that has taken to prepare for value-based reimbursement and transform its dental practice in order to reduce the disease burden in its patient population. The purpose of this article is to describe the processes YVFWC undertook to prepare itself for the new reimbursement model, which included the development of metrics, a metric validation process, a clinical dashboard, and a method for improving metrics. It also outlines its medical/dental integration improvement brought about by embedding hygienists into the medical primary care teams.  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