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   155178篇
  免费   13650篇
  国内免费   6607篇
耳鼻咽喉   1341篇
儿科学   4630篇
妇产科学   2912篇
基础医学   21893篇
口腔科学   3382篇
临床医学   11903篇
内科学   23229篇
皮肤病学   2486篇
神经病学   9533篇
特种医学   3190篇
外国民族医学   48篇
外科学   15266篇
综合类   24027篇
现状与发展   27篇
预防医学   7385篇
眼科学   4468篇
药学   19564篇
  44篇
中国医学   7430篇
肿瘤学   12677篇
  2024年   180篇
  2023年   2098篇
  2022年   3241篇
  2021年   5768篇
  2020年   4885篇
  2019年   5081篇
  2018年   5204篇
  2017年   5708篇
  2016年   5504篇
  2015年   6161篇
  2014年   10157篇
  2013年   11313篇
  2012年   10224篇
  2011年   11465篇
  2010年   9209篇
  2009年   8846篇
  2008年   8676篇
  2007年   8279篇
  2006年   7331篇
  2005年   6374篇
  2004年   5498篇
  2003年   4719篇
  2002年   3728篇
  2001年   3166篇
  2000年   2664篇
  1999年   2191篇
  1998年   1936篇
  1997年   1780篇
  1996年   1342篇
  1995年   1443篇
  1994年   1244篇
  1993年   1101篇
  1992年   947篇
  1991年   813篇
  1990年   755篇
  1989年   639篇
  1988年   504篇
  1987年   454篇
  1986年   451篇
  1985年   701篇
  1984年   662篇
  1983年   423篇
  1982年   521篇
  1981年   403篇
  1980年   344篇
  1979年   266篇
  1978年   206篇
  1977年   190篇
  1976年   205篇
  1975年   126篇
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
1.
《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   
2.
3.
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   
4.
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   
5.
《Cancer cell》2022,40(3):318-334.e9
  1. Download : Download high-res image (268KB)
  2. Download : Download full-size image
  相似文献   
6.
目的:探讨消化道肿瘤中同源重组修复相关基因(homologous recombination repair related gene,HRR)突变的发生情况及临床意义。方法:共92例消化道肿瘤患者,79例患者进行了血液标本HRR检测,53例患者进行了组织标本HRR检测,40例患者同时行血液和组织的HRR基因检测,收集患者基因检测结果及临床相关资料。结果:在79例患者血液标本检测中发现10例(12.6%)有临床意义HRR突变,在53例患者组织标本检测中发现9例(17.0%)有临床意义HRR突变。40例同时行血液和组织的HRR基因检测患者中常见的有临床意义HRR突变为CDK12突变4例(10.0%)、ATM突变3例(7.5%)、BRCA1突变2例(5.0%)。13例有临床意义HRR突变患者中常见共存突变为TP53突变10例(76.9%)、APC突变5例(38.5%)、PIK3CA突变4例(30.8%)。40例患者中13例患者血液和/或组织中有临床意义HRR突变,27例患者血液和组织中均无任何临床意义HRR突变且两组相比,有临床意义HRR突变组肿瘤突变负荷(tumor mutational burden,TMB)为6.17(2.24~11.52),而未携带HRR突变组TMB为0.4(0~3.75),差异有统计学意义(P<0.05)。40例患者组织检测中7例HRR有临床意义的突变,33例无HRR突变,血液检测中10例HRR有临床意义的突变,30例无HRR突变,一致性检验的Kappa值为0.333(P=0.031)。结论:携带有临床意义HRR突变的消化道肿瘤患者TMB更高,血液和组织检测HRR突变有较好的一致性。  相似文献   
7.
8.
Bortezomib is a novel proteasome inhibitor, which has been successfully used to treat mantle cell lymphoma and multiple myeloma. However, the direct effects of bortezomib on acute promyelocytic leukaemia (APL) have not been fully investigated. In the present study, the WST-8 assay, western blotting, flow cytometry, monodansylcadaverine staining and transmission electron microscopy were performed. It was demonstrated that bortezomib treatment induced a time- and dose-dependent decrease in the viability of NB4 cells. Bortezomib treatment induced cell apoptosis in NB4 cells, as assessed by Annexin V/propidium iodide analysis, and the detection of cleaved caspase-3, cleaved poly(ADP-ribose) polymerase, Bax and Bcl-2 expression. Furthermore, bortezomib treatment induced autophagy in NB4 cells, as indicated by autophagosome formation, p62 degradation, LC3-I to LC3-II conversion and formation of acidic autophagic vacuoles. Notably, autophagy induced by bortezomib was initiated prior to apoptosis. Inhibition of autophagy by knocking down Beclin-1 expression increased bortezomib-induced apoptosis in NB4 cells. Therefore, the present study revealed that the combination of bortezomib and autophagy inhibition may be a potential treatment strategy for APL.  相似文献   
9.
《Digestive and liver disease》2022,54(11):1486-1493
BackgroundCold snare polypectomy (CSP) is a promising technique for the removal of sessile serrated polyps (SSPs) ≥ 10 mm. However, the efficacy and safety of this technique remain undetermined.AimsWe aimed to comprehensively evaluate the efficacy and safety of CSP for SSPs ≥ 10 mm.MethodsPubMed, EMBASE, Web of Science and Cochrane Library were searched up to January 2021.ResultsA total of 10 studies consisting of 1727 SSPs (range, 10–40 mm) from 1021 patients were included. The overall rates of technical success, adverse events (AEs) and residual SSPs were 100%, 0.7% and 2.9%, respectively. Subgroup analysis showed that the rates of technical success and AEs were comparable between CSP and cold endoscopic mucosal resection (EMR) (99.9% vs. 100% and 1.3% vs. 0.5%, respectively), between the proximal and distal colon (100% vs. 99.9% and 0.3% vs. 0, respectively), and between polyps of 10–19 mm and ≥20 mm (99.8% vs. 100% and 0.9% vs. 0, respectively). However, subgroup analysis showed that the rate of residual SSPs was slightly lower in CSP compared with cold EMR (1.3% vs. 3.9%), as well as in polyps of 10–19 mm compared with those ≥20 mm (3.1% vs. 4.7%).ConclusionCSP was an effective and safe technique for removing SSPs ≥ 10 mm.  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