全文获取类型
收费全文 | 91245篇 |
免费 | 10763篇 |
国内免费 | 2652篇 |
专业分类
耳鼻咽喉 | 520篇 |
儿科学 | 1810篇 |
妇产科学 | 1573篇 |
基础医学 | 8711篇 |
口腔科学 | 2604篇 |
临床医学 | 10013篇 |
内科学 | 14819篇 |
皮肤病学 | 853篇 |
神经病学 | 6640篇 |
特种医学 | 2454篇 |
外国民族医学 | 3篇 |
外科学 | 8687篇 |
综合类 | 12125篇 |
现状与发展 | 13篇 |
一般理论 | 9篇 |
预防医学 | 14588篇 |
眼科学 | 1452篇 |
药学 | 8602篇 |
98篇 | |
中国医学 | 3203篇 |
肿瘤学 | 5883篇 |
出版年
2024年 | 300篇 |
2023年 | 2150篇 |
2022年 | 2844篇 |
2021年 | 5346篇 |
2020年 | 4759篇 |
2019年 | 4103篇 |
2018年 | 4018篇 |
2017年 | 4031篇 |
2016年 | 3931篇 |
2015年 | 3895篇 |
2014年 | 6510篇 |
2013年 | 7792篇 |
2012年 | 5311篇 |
2011年 | 5899篇 |
2010年 | 4510篇 |
2009年 | 4591篇 |
2008年 | 4588篇 |
2007年 | 4357篇 |
2006年 | 3780篇 |
2005年 | 3365篇 |
2004年 | 2682篇 |
2003年 | 2290篇 |
2002年 | 1839篇 |
2001年 | 1659篇 |
2000年 | 1404篇 |
1999年 | 1171篇 |
1998年 | 967篇 |
1997年 | 857篇 |
1996年 | 715篇 |
1995年 | 660篇 |
1994年 | 592篇 |
1993年 | 539篇 |
1992年 | 460篇 |
1991年 | 370篇 |
1990年 | 340篇 |
1989年 | 298篇 |
1988年 | 254篇 |
1987年 | 228篇 |
1986年 | 177篇 |
1985年 | 233篇 |
1984年 | 189篇 |
1983年 | 99篇 |
1982年 | 130篇 |
1981年 | 98篇 |
1980年 | 92篇 |
1979年 | 70篇 |
1978年 | 42篇 |
1977年 | 40篇 |
1976年 | 30篇 |
1974年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
61.
《The Journal of thoracic and cardiovascular surgery》2023,165(1):149-158.e4
BackgroundCoronary artery bypass grafting (CABG) improves survival in patients with heart failure and severely reduced left ventricular systolic function (LVEF). Limited data exist regarding adverse cardiovascular event rates after CABG in patients with heart failure with midrange ejection fraction (HFmrEF; LVEF > 40% and < 55%).MethodsWe analyzed data on isolated CABG patients from the Veterans Affairs national database (2010-2019). We stratified patients into control (normal LVEF and no heart failure), HFmrEF, and heart failure with reduced LVEF (HFrEF) groups. We compared all-cause mortality and heart failure hospitalization rates between groups with a Cox model and recurrent events analysis, respectively.ResultsIn 6533 veterans, HFmrEF and HFrEF was present in 1715 (26.3%) and 566 (8.6%) respectively; the control group had 4252 (65.1%) patients. HFrEF patients were more likely to have diabetes mellitus (59%), insulin therapy (36%), and previous myocardial infarction (31%). Anemia was more prevalent in patients with HFrEF (49%) as was a lower serum albumin (mean, 3.6 mg/dL). Compared with the control group, a higher risk of death was observed in the HFmrEF (hazard ratio [HR], 1.3 [1.2-1.5)] and HFrEF (HR, 1.5 [1.2-1.7]) groups. HFmrEF patients had the higher risk of myocardial infarction (subdistribution HR, 1.2 [1-1.6]; P = .04). Risk of heart failure hospitalization was higher in patients with HFmrEF (HR, 4.1 [3.5-4.7]) and patients with HFrEF (HR, 7.2 [6.2-8.5]).ConclusionsHeart failure with midrange ejection fraction negatively affects survival after CABG. These patients also experience higher rates myocardial infarction and heart failure hospitalization. 相似文献
62.
阐述当前“人工智能+X”背景下市场对医学信息管理专业人才能力的需求,分析医学信息管理专业人才培养现状,提出从重塑学科人才培养目标、优化课程内容与课程设置、建设“双师型”导师队伍、搭建多方协同共建共享在线平台及设立“政用产学研”联合培养基地等方面探索医学信息管理专业研究生培养模式,以期培养适应人工智能时代发展,具备学科优势特色的高层次、高水平、高质量的复合型、应用型、创新型人才。 相似文献
63.
器官移植术是20世纪出现的针对器官功能衰竭的最有效治疗方法,每年拯救全球超过12万例患者。但供器官短缺的现状,与器官移植技术和辅助药物的发展不匹配,制约了器官移植事业的发展。我国自2015年起已成为全球器官捐献和移植大国之一,2017年公民逝世后器官捐献数量超过5 000例,占全球捐献总量的15%以上。黄洁夫教授总结的器官捐献与移植"中国模式"得到了世界卫生组织、国际移植界的高度重视和充分肯定。本文通过整理全球及各国的器官捐献与移植数据,剖析全球现状与发展趋势,进一步探索我国公民器官捐献的影响因素并提出针对性的应对策略,以期实现我国器官捐献和移植的"自给自足"。 相似文献
64.
65.
目的:探讨早产儿消化道穿孔的病因,分析影响早产儿消化道穿孔短期预后不良的危险因素。方法:回顾性分析山西省
儿童医院新生儿外科2015年1月—2021 年5月诊治的89 例早产儿消化道穿孔的临床资料。根据术后3 个月时结局分为生存
组和预后不良组。比较两组术前、术中及术后与早产儿消化道穿孔预后不良相关的因素,采用Logistic 回归分析筛选早产儿消
化道穿孔预后不良的危险因素。结果:早产儿消化道穿孔的病死率为25.84%,坏死性小肠结肠炎(NEC)和胃壁肌层缺损是早产
儿消化道穿孔常见的病因。单因素分析显示生存组患儿从发现气腹至手术时间在8 h 之内的比例显著高于预后不良组
(χ2=15.22,P<0.01)。预后不良组合并脓毒性休克的比例显著高于生存组(χ2=33.19,P<0.01)。预后不良组术后合并需非计划二次
手术的并发症比例显著高于生存组(χ2=7.24,P<0.01)。Logistic 回归分析显示脓毒性休克(OR=0.06,95%CI:0.02~0.21,P<0.01)和
气腹至手术时间大于8 h(OR=0.23,95%CI:0.07~0.81,P<0.05)是早产儿消化道穿孔短期预后不良的危险因素。结论:NEC 和胃
壁肌层缺损是早产儿消化道穿孔的主要病因,脓毒性休克和从气腹发生至手术时间大于8 h 是早产儿消化道穿孔短期预后
不良的危险因素。 相似文献
66.
目的:探讨二补助育汤对胚胎着床障碍模型小鼠子宫内膜形态及血管生成素-1(Ang-1)mRNA、血管内皮生长因子(VEGF)mRNA的表达和定位的影响。方法:24只ICR雌性小鼠随机分为空白组、模型组、戊酸雌二醇组、二补助育汤组,每组6只,用米非司酮建立胚胎着床障碍动物模型,各组给予相应药物灌胃,妊娠第5天处死小鼠后,检测各组妊娠率、平均着床位点数、子宫内膜Ang-1和VEGF mRNA表达量及其蛋白定位。结果:模型组小鼠平均胚胎着床位点数、Ang-1 mRNA、VEGF mRNA表达量明显低于空白组(均P<0.05);与模型组比较,二补助育汤组平均胚胎着床位点数、Ang-1 mRNA、VEGF mRNA表达量显著提高(均P<0.05)。结论:二补助育汤可提高子宫内膜Ang-1和VEGF蛋白表达量,促进子宫内膜血管生成,从而提高子宫内膜容受性。 相似文献
67.
Sandrine F. Chebekoue 《Journal of occupational and environmental hygiene》2019,16(4):308-319
This study aimed at deriving occupational thresholds of toxicological concern for inhalation exposure to systemically-acting organic chemicals using predicted internal doses. The latter were also used to evaluate the quantitative relationship between occupational exposure limit and internal dose. Three internal dose measures were identified for investigation: (i) the daily area under the venous blood concentration vs. time curve, (ii) the daily rate of the amount of parent chemical metabolized, and (iii) the maximum venous blood concentration at the end of an 8-hr work shift. A dataset of 276 organic chemicals with 8-hr threshold limit values-time-weighted average was compiled along with their molecular structure and Cramer classes (Class I: low toxicity, Class II: intermediate toxicity, Class III: suggestive of significant toxicity). Using a human physiologically-based pharmacokinetic model, the three identified dose metrics were predicted for an 8-hr occupational inhalation exposure to the threshold limit value for each chemical. Distributional analyses of the predicted dose metrics were performed to identify the percentile values corresponding to the occupational thresholds of toxicological concern. Also, simple linear regression analyses were performed to evaluate the relationship between the 8-hr threshold limit value and each of the predicted dose metrics, respectively. No threshold of toxicological concern could be derived for class II due to few chemicals. Based on the daily rate of the amount of parent chemical metabolized, the proposed internal dose-based occupational thresholds of toxicological concern were 5.61?×?10?2 and 9?×?10?4 mmol/d at the 10th percentile level for classes I and III, respectively, while they were 4.55?×?10?1 and 8.5?×?10?3 mmol/d at the 25th percentile level. Even though high and significant correlations were observed between the 8-hr threshold limit values and the predicted dose metrics, the one with the rate of the amount of chemical metabolized was remarkable regardless of the Cramer class (r2 = 0.81; n = 276). The proposed internal dose-based occupational thresholds of toxicological concern are potentially useful for screening-level assessments as well as prioritization within an integrated occupational risk assessment framework. 相似文献
68.
Ryo Tanaka Kenta Hirohama Junya Ozawa 《Revista brasileira de fisioterapia (S?o Carlos (S?o Paulo, Brazil))》2019,23(3):266-272
ObjectiveTo verify if the relationship between pain catastrophizing and pain worsening would be mediated by muscle weakness and disability in patients with symptomatic knee osteoarthritis.MethodsThis was a cross-sectional study in a hospital out-patient setting. Convenience sampling was used with a total of 50 participants with symptomatic knee osteoarthritis. Pain and the activities of daily livings (ADL) were assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale. Pain catastrophizing was assessed using the Coping Strategy Questionnaire (CSQ) subscale. Muscle strength of knee extension and 30-s chair stand test (30CST) were also assessed. Path analysis was performed to test the hypothetical model. Goodness of fit of models were assessed by using statistical parameters such as the chi-square value, goodness of fit index (GFI), adjusted goodness of fit index (AGFI), comparative fit index (CFI), and root mean square error of approximation (RMSEA).ResultsThe chi-square values were not significant (chi-square = 0.283, p = 0.594), and the indices of goodness of fit were high, implying a valid model (GFI = 1.000; AGFI = 0.997; CFI = 1.000; RMSEA = 0.000). Pain was influenced significantly by muscle strength and ADL; muscle strength was influenced significantly by ADL via 30CST; ADL was influenced by pain catastrophizing.ConclusionThe relationship between pain catastrophizing with pain worsening are mediated by muscle weakness and disability. 相似文献
69.
70.