全文获取类型
收费全文 | 30439篇 |
免费 | 3257篇 |
国内免费 | 1791篇 |
专业分类
耳鼻咽喉 | 325篇 |
儿科学 | 452篇 |
妇产科学 | 121篇 |
基础医学 | 1830篇 |
口腔科学 | 493篇 |
临床医学 | 3586篇 |
内科学 | 2609篇 |
皮肤病学 | 331篇 |
神经病学 | 567篇 |
特种医学 | 1507篇 |
外科学 | 2893篇 |
综合类 | 8256篇 |
现状与发展 | 13篇 |
预防医学 | 3712篇 |
眼科学 | 431篇 |
药学 | 3651篇 |
49篇 | |
中国医学 | 3397篇 |
肿瘤学 | 1264篇 |
出版年
2024年 | 174篇 |
2023年 | 456篇 |
2022年 | 1164篇 |
2021年 | 1357篇 |
2020年 | 1215篇 |
2019年 | 699篇 |
2018年 | 649篇 |
2017年 | 910篇 |
2016年 | 670篇 |
2015年 | 1251篇 |
2014年 | 1538篇 |
2013年 | 1973篇 |
2012年 | 2959篇 |
2011年 | 2971篇 |
2010年 | 2725篇 |
2009年 | 2423篇 |
2008年 | 2483篇 |
2007年 | 2244篇 |
2006年 | 2008篇 |
2005年 | 1618篇 |
2004年 | 1044篇 |
2003年 | 915篇 |
2002年 | 645篇 |
2001年 | 624篇 |
2000年 | 470篇 |
1999年 | 131篇 |
1998年 | 26篇 |
1997年 | 26篇 |
1996年 | 24篇 |
1995年 | 15篇 |
1994年 | 13篇 |
1993年 | 14篇 |
1992年 | 7篇 |
1991年 | 14篇 |
1990年 | 9篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 5篇 |
1982年 | 1篇 |
1959年 | 2篇 |
1956年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
目的针对一例无症状的8号染色体三体的患者,研究其8号染色体的来源机制和作用机制。方法利用患者外周血进行淋巴细胞培养及G显带技术分析,以确定淋巴细胞核型;利用患者外周血总DNA进行SNP微阵列技术分析,以确定各类有核细胞的分子核型。结果患者外周血淋巴细胞核型为47,XX,+8;患者外周血各种有核细胞总DNA基因型为47,XX,+8。结论确诊患者外周血有核细胞的核型均为47,XX,+8,并且多出来的那条染色体可能由于第二次减数分裂不分离而导致的,尚不能明确该患者没有明显临床症状的机制。 相似文献
73.
74.
目的:探讨Geminin基因沉默对人脑胶质瘤细胞恶性生物学行为的影响及可能的发生机制.方法:选取南通大学附属医院脑外科2018-2019年手术切除的20例神经胶质瘤患者的新鲜标本,qRT-PCR结合基因表达谱数据动态分析(gene expression profilling interactive analysis,G... 相似文献
75.
Jie LIU Xin-Xing FENG Yan-Feng DUAN Jun-Hao LIU Ce ZHANG Lin JIANG Lian-Jun XU Jian TIAN Xue-Yan ZHAO Yin ZHANG Kai SUN Bo XU Wei ZHAO Ru-Tai HUI Run-Lin GAO Ji-Zheng WANG Jin-Qing YUAN Xin HUANG Lei SONG 《老年心脏病学杂志》2022,19(5):367
BACKGROUNDThree-vessel disease (TVD) with a SYNergy between PCI with TAXus and cardiac surgery (SYNTAX) score of ≥ 23 is one of the most severe types of coronary artery disease. We aimed to take advantage of machine learning to help in decision-making and prognostic evaluation in such patients.METHODSWe analyzed 3786 patients who had TVD with a SYNTAX score of ≥ 23, had no history of previous revascularization, and underwent either coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) after enrollment. The patients were randomly assigned to a training group and testing group. The C4.5 decision tree algorithm was applied in the training group, and all-cause death after a median follow-up of 6.6 years was regarded as the class label.RESULTSThe decision tree algorithm selected age and left ventricular end-diastolic diameter (LVEDD) as splitting features and divided the patients into three subgroups: subgroup 1 (age of ≤ 67 years and LVEDD of ≤ 53 mm), subgroup 2 (age of ≤ 67 years and LVEDD of > 53 mm), and subgroup 3 (age of > 67 years). PCI conferred a patient survival benefit over CABG in subgroup 2. There was no significant difference in the risk of all-cause death between PCI and CABG in subgroup 1 and subgroup 3 in both the training data and testing data. Among the total study population, the multivariable analysis revealed significant differences in the risk of all-cause death among patients in three subgroups.CONCLUSIONSThe combination of age and LVEDD identified by machine learning can contribute to decision-making and risk assessment of death in patients with severe TVD. The present results suggest that PCI is a better choice for young patients with severe TVD characterized by left ventricular dilation.Coronary artery disease (CAD) is the leading cause of death and disability worldwide.[1] Three-vessel disease (TVD) is the most severe form of CAD and is characterized by significant stenosis in all three major coronary arteries. The application of myocardial revascularization techniques, including coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI), has significantly improved the clinical outcomes of patients with severe CAD. CABG has traditionally been the standard therapy for complex coronary lesions, including TVD.[2] In recent years, with the advancements in PCI technology and the accumulation of operators’ experience, the incidence of periprocedural and long-term adverse events of PCI has substantially decreased, and PCI has been gradually applied in the treatment of TVD.[3,4] Current guidelines recommend use of the SYNergy between PCI with TAXus and cardiac surgery (SYNTAX) score and diabetes status to guide the revascularization strategy for patients with TVD.[5,6] Current practice guidelines do not recommend PCI for patients with TVD with a SYNTAX score of ≥ 23. However, using the SYNTAX score to guide clinical decision-making between PCI and CABG remains controversial, and its reasonability has been questioned since a newly published meta-analysis showed no significant association between the SYNTAX score and the comparative effectiveness of PCI and CABG.[7] Moreover, the SYNTAX score is a quantitative indicator of the anatomical complexity of TVD and does not include clinical variables that may have significant effects on the patient’s prognosis. Whether some patients with specific clinical characteristics can obtain a comparable or even greater survival benefit from PCI than from CABG is unclear. Moreover, risk assessment for patients with TVD after revascularization therapy remain challenging.[8–10]Machine learning has recently emerged as an important research method and has been successfully applied in many scientific fields, including clinical medicine.[11–13] The decision tree algorithm, a common approach in machine learning, can handle non-linearity, heterogeneous effects, and high-dimensional features and partition a trial population into subgroups characterized by multiple simultaneous characteristics.[14] In the present study involving a large cohort of patients with TVD with a SYNTAX score of ≥ 23, we employed a decision tree algorithm to generate specific subgroups, compared the long-term prognosis between patients who underwent PCI or CABG in each subgroup, and conducted a comparative analysis of the long-term prognosis between subgroups generated by machine learning. We evaluated whether machine learning can help in selecting the optimal revascularization method and assessing risk in patients with severe TVD. 相似文献
76.
目的了解宝鸡市乙型肝炎发病情况及流行病学特征,为制定控制策略和措施提供科学依据。方法采用描述流行病学方法,对2000-2007年宝鸡市乙型肝炎疫情资料进行统计分析。结果2000~2004年各年龄组发病率呈上升趋势,2005年起各年龄组发病率均有所下降,特别是14岁以下儿童发病率下降比较明显。农村发病明显高于城区。发病构成中农民所占比例最高,占乙型肝炎发病总数的51.85%,幼托儿童和散居儿童发病构成呈下降趋势。结论14岁以下儿童乙肝免疫防治策略已初见成效。应在加强新生儿及儿童乙型肝炎免疫接种工作的同时,加大对中青年及农村劳动人口乙型肝炎疫苗的免疫接种工作。 相似文献
77.
目的 比较Victoria blue法(A组)和Verhoeff法(B组)弹力纤维染色在染色过程、染色时间、染色效果方面对肺癌胸膜侵犯和结直肠癌浆膜或静脉侵犯判读的差异。方法 A组、B组均分别纳入肺癌怀疑胸膜侵犯标本50例和结直肠癌怀疑浆膜或静脉侵犯标本20例,进行弹力纤维染色。对比2组染色过程、染色时间、染色效果;根据染色稳定性、清晰度、对比度等综合评价胸膜侵犯和浆膜或静脉侵犯情况,并对染色质量及判读准确性进行评分。结果 A组比B组操作简单,染色质量稳定,肿瘤细胞与脏层胸膜、浆膜或静脉的关系显示更清晰。A组判读评分高于B组,差异有统计学意义(P<0.05)。结论 Victoria blue法染色有助于准确评估肺癌的胸膜侵犯和结直肠癌浆膜或静脉的侵犯,提高判读准确性。 相似文献
78.
中医学重视人体正气在恶性肿瘤防治中的关键作用,强调"调和阴阳,以平为期",刘嘉湘教授创建"以人为本"、"顾护正气"为核心特征的"扶正治癌"学术体系,强调调控机体内在抵抗力(含免疫功能)以防治恶性肿瘤;肿瘤免疫治疗的疗效已经在泛癌种范围内得以确认,被认为是"最有可能治愈癌症"的疗法.从肿瘤免疫学角度深入研究人体"正气"的... 相似文献
79.
目的:探讨经皮腔内血管成形术(PTA)结合支架植入术对股胭动脉TASCⅡ-C、D级病变的技术方法和治疗效果.方法:回顾性分析我院从2008年9月~2010年5月对股腘动脉硬化闭塞症TASC Ⅱ-C、D级病变的52例患者(60条肢体).采用顺行或逆行股动脉穿刺途径,通过常规技术或内膜下血管成形术(SIA)通过狭窄或闭塞性病变.进行球囊扩张成形,部分患者行支架植入,分析介入治疗技术、临床症状改善情况、并发症发生情况及随访情况.结果:56条肢体获得技术成功,成功率为93.3%(56/60),无围手术期死亡者,并发症发生率为6.67%(4/60),主要有导丝穿破血管壁及穿刺点血肿等,根据情况给予相应处理.术后第1周踝/肱指数(ABI)由术前的0.42士0.11增至术后7d的0.85士0.18(t=15.79 P <0.001).术后随访45例患者(51条肢体)6~22个月(平均10.7个月).术后6个月、12个月肢体一期通畅率分别为94.1%(48/51)和73.7%(28/38).术后l2个月肢体保全率和存活率分别为I00%(38/38)和89 5%(34/38).结论:血管腔内介入治疗TASCⅡ-C、D级股腘动脉硬化闭塞症的临床成功率高、并发症少、救肢率高,是安全有效的治疗方法,近期效果确切,其长期疗效尚须进一步观察. 相似文献
80.
目的 探讨增殖细胞核抗原在不同病理类型髓母细胞瘤中的表达差异和临床意义.方法 对34例髓母细胞瘤(经典型61.8%,促硬纤维增生型38.2%)进行增殖细胞核抗原的免疫组化染色,测定不同类型髓母细胞瘤的增殖细胞核抗原指数.结果 经典型髓母细胞瘤的增殖细胞核抗原指数为(81.45±9.29)%,促硬纤维增生型髓母细胞瘤增殖细胞核抗原指数为(39.86±8.37)%,不同髓母细胞瘤亚型的增殖细胞核抗原指数值存在显著差异(P<0.01).结论 增殖细胞核抗原的表达差异,为不同亚型髓母细胞瘤的生物行为学差异提供了病理学依据,增殖细胞核抗原指数可以作为髓母细胞瘤恶性程度及患者预后判断指标. 相似文献