全文获取类型
收费全文 | 51778篇 |
免费 | 5450篇 |
国内免费 | 1929篇 |
专业分类
耳鼻咽喉 | 373篇 |
儿科学 | 529篇 |
妇产科学 | 590篇 |
基础医学 | 6315篇 |
口腔科学 | 1471篇 |
临床医学 | 4944篇 |
内科学 | 6321篇 |
皮肤病学 | 429篇 |
神经病学 | 3826篇 |
特种医学 | 1708篇 |
外国民族医学 | 2篇 |
外科学 | 4702篇 |
综合类 | 8361篇 |
现状与发展 | 5篇 |
预防医学 | 7593篇 |
眼科学 | 847篇 |
药学 | 5581篇 |
78篇 | |
中国医学 | 2922篇 |
肿瘤学 | 2560篇 |
出版年
2024年 | 342篇 |
2023年 | 1308篇 |
2022年 | 2473篇 |
2021年 | 2928篇 |
2020年 | 2414篇 |
2019年 | 1956篇 |
2018年 | 1824篇 |
2017年 | 2024篇 |
2016年 | 1870篇 |
2015年 | 2028篇 |
2014年 | 3296篇 |
2013年 | 3820篇 |
2012年 | 2971篇 |
2011年 | 3363篇 |
2010年 | 2594篇 |
2009年 | 2715篇 |
2008年 | 2677篇 |
2007年 | 2639篇 |
2006年 | 2249篇 |
2005年 | 2017篇 |
2004年 | 1595篇 |
2003年 | 1402篇 |
2002年 | 1069篇 |
2001年 | 952篇 |
2000年 | 881篇 |
1999年 | 744篇 |
1998年 | 585篇 |
1997年 | 539篇 |
1996年 | 469篇 |
1995年 | 420篇 |
1994年 | 398篇 |
1993年 | 334篇 |
1992年 | 308篇 |
1991年 | 243篇 |
1990年 | 241篇 |
1989年 | 202篇 |
1988年 | 175篇 |
1987年 | 165篇 |
1986年 | 125篇 |
1985年 | 163篇 |
1984年 | 133篇 |
1983年 | 76篇 |
1982年 | 91篇 |
1981年 | 74篇 |
1980年 | 69篇 |
1979年 | 56篇 |
1978年 | 36篇 |
1977年 | 31篇 |
1976年 | 26篇 |
1975年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
目的 建立大鼠颈总动脉与颈外静脉吻合高血流性肺动脉高压模型。方法 健康雄性SD大鼠45只分为分流组、结扎组和假手术组(n=15)。12 周后检查大鼠一般状态;超声心动图观察心脏情况、心排量及分流通畅情况;右心导管检查右心室收缩压,抽血气分析计算肺循环/体循环血流量比值(Qp/Qs); 右心室肥厚指数;肺组织HE染色及弹力纤维EVG染色。统计数据采用SPSS 16.0软件,对各组数据进行单因素方差验分析。结果 各组体重增加未见明显差异,吻合通畅率84.6%。分流组大鼠心脏明显增大,与假手术组、结扎组相比心排量明显增加[(309.8±33.1)mL/min·kg比(245.6±31.9)mL/min·kg,(240.8±30.9)mL/min·kg相比,P<0.05];分流组Qp/Qs 为2.16±0.38,右心室收缩压增加至(35.8±4.9)mmHg。分流组右心室肥厚指数0.3263±0.0342,比其它两组增加明显。与假手术组相比,分流组肺动脉中膜厚度明显增加[(22.3±1.7)% 比(10.6±1.7)%, P<0.05]。结论 大鼠颈总动脉与颈外静脉吻合法可以建立良好的高肺血流肺动脉高压模型。 相似文献
992.
本文介绍了预测模型研究的偏倚风险和适用性评估工具PROBAST(Prediction model Risk Of Bias ASsessment Tool)的主要内容、评价步骤和相关注意事项。PROBAST从研究对象、预测因素、结局和分析4个领域共20个信号问题对原始研究的设计、实施和分析过程中可能产生的偏倚风险和适用性进行评价。通过综合分析,对原始研究每个领域和整体的偏倚风险和适用性做出判断,分为高、低或不清楚。PROBAST为个体预测模型开发、验证和更新提供了可靠的新评价工具,它不仅可以用于预测模型的系统综述,也可作为预测模型研究通用的方法学评价工具。 相似文献
993.
由于经方由药材构成,药材又由成分组成,成分和靶点在靶点数据库中可以建立直接联系.因此先提取经方配方和经方成分;然后进行靶点提取,借助靶点数据库构建靶点筛选模型;最后将不同来源的靶点汇总,计算靶点置信度,绘制经方靶点预测.根据经方到靶点的不同路径建立从经方到靶点之间的联系,构建经方靶点预测模型,并以芍药甘草汤和大黄黄连泄... 相似文献
994.
目的 根据脑血管血液动力学参数(CVHI)和脑卒中的主要危险因素建立脑卒中预测模型。方法 选择全国六大行政区脑卒中研究队列人群25355例,将基线调查时的CVHI检测结果 进行主成分分析,再以各主成分和主要脑卒中危险因素为自变量,以随访中脑卒中发病为应变量进行回归分析,根据回归系数建立脑卒中预测模型,计算发病概率,绘制ROC曲线,确定最佳截断点,评价预测模型的预测效能。结果 四个主成分的累积贡献率依次为58.1%、79.4%、88.4%和94.6%,被筛检进入logistic回归方程的变量分别为第一至第四主成分、高血压病史、年龄和性别,ROC曲线下面积为0.855,最佳截断点为预测概率≥0.05,预测脑卒中的敏感度、特异度和准确度分别为踟.7%,78.5%,78.5%。结论 通过主成分回归分析,可以建立具有良好效能的脑卒中预测模型。 相似文献
995.
996.
Yu Lei Xin Zhang Wei Ni Heng Yang Jia-Bin Su Bin Xu Liang Chen Jin-Hua Yu Yu-Xiang Gu Ying Mao 《中国神经再生研究》2021,16(5):830
Although intracranial hemorrhage in moyamoya disease can occur repeatedly, predicting the disease is difficult. Deep learning algorithms developed in recent years provide a new angle for identifying hidden risk factors, evaluating the weight of different factors, and quantitatively evaluating the risk of intracranial hemorrhage in moyamoya disease. To investigate whether convolutional neural network algorithms can be used to recognize moyamoya disease and predict hemorrhagic episodes, we retrospectively selected 460 adult unilateral hemispheres with moyamoya vasculopathy as positive samples for diagnosis modeling, including 418 hemispheres with moyamoya disease and 42 hemispheres with moyamoya syndromes. Another 500 hemispheres with normal vessel appearance were selected as negative samples. We used deep residual neural network(Res Net-152) algorithms to extract features from raw data obtained from digital subtraction angiography of the internal carotid artery, then trained and validated the model. The accuracy, sensitivity, and specificity of the model in identifying unilateral moyamoya vasculopathy were 97.64 ± 0.87%, 96.55 ± 3.44%, and 98.29 ± 0.98%, respectively. The area under the receiver operating characteristic curve was 0.990. We used a combined multi-view conventional neural network algorithm to integrate age, sex, and hemorrhagic factors with features of the digital subtraction angiography. The accuracy of the model in predicting unilateral hemorrhagic risk was 90.69 ± 1.58% and the sensitivity and specificity were 94.12 ± 2.75% and 89.86 ± 3.64%, respectively. The deep learning algorithms we proposed were valuable and might assist in the automatic diagnosis of moyamoya disease and timely recognition of the risk for re-hemorrhage. This study was approved by the Institutional Review Board of Huashan Hospital, Fudan University, China(approved No. 2014-278) on January 12, 2015. 相似文献
997.
目的 基于超高效液相色谱-四极杆-飞行时间串联质谱(UPLC-Q-TOF-MS)指纹图谱和分子对接技术,确定藿香正气水(Huoxiang Zhengqi Shui,HZS)抗新型冠状病毒(SARS-CoV-2)的潜在质量标志物(quality markers,Q-Marker)。方法 对27批HZS样品建立UPLC-Q-TOF-MS指纹图谱,结合化学计量学方法,筛选出HZS的差异性成分;以瑞德西韦为阳性对照,将HZS的差异性成分与SARS-CoV-2主蛋白酶(main protease,Mpro)进行分子对接,进一步确定HZS的潜在Q-Marker。结果 通过建立27批HZS样品的UPLC-Q-TOF-MS指纹图谱,标定了27种共有化合物;结合层次聚类分析(hierarchical clustering analysis,HCA)和主成分分析(principal component analysis,PCA),确定了其中14种共有化合物在27批HZS样品中具有较大的差异性,并鉴定出了橙皮苷、氧化前胡素、新比克白芷内脂、甜橙素、甘草酸、3,5,6,7,8,3'',4''-七甲氧基黄酮、桔皮素、欧前胡素、珊瑚菜素9种差异性化合物;9种差异性化合物的分子对接结果显示,橙皮苷、氧化前胡素、新比克白芷内脂、甘草酸、欧前胡素、珊瑚菜素6种化合物能与SARS-CoV-2 Mpro的活性氨基酸结合,具有抑制SARS-CoV-2 Mpro的潜能,可作为HZS的潜在Q-Marker。结论 将UPLC-Q-TOF-MS指纹图谱、化学计量学分析和分子对接技术交叉使用,确定了HZS的潜在Q-Marker,该方法为药物成分鉴定、同一类药物成分差异性分析,及其功效研究方面提供一定参考。 相似文献
998.
《Journal of vascular and interventional radiology : JVIR》2019,30(6):922-927
PurposeTo generate 3-dimensional (3D) printed ultrasound (US)-compatible vascular models (3DPVAM) and test them for noninferiority in training medical students in femoral artery access.Materials and MethodsA 3DPVAM of normal femoral artery (FA) anatomy was developed from an anonymized computerized tomography (CT) examination. Students were randomized to a 3DPVAM or a commercial model (CM) simulation experience (SE) for US-guided FA access. Students completed a pre-SE questionnaire ranking their self-confidence in accessing the artery on a 5-point Likert scale. A standardized SE was administered by interventional radiology faculty or trainees. Students completed a post-SE questionnaire ranking comfort with FA access on a Likert scale. Student questionnaire results from the 3DPVAM group were compared with those from the CM group by using chi-square, Wilcoxon signed-rank, and noninferiority analyses.ResultsTwenty-six and twenty-three students were randomized to 3DPVAM and commercial model training, respectively. A total of 76.9% of 3DPVAM trainees and 82.6% of CM trainees did not feel confident performing FA access prior to the SE. In both groups, training increased student confidence by 2 Likert points (3DPVAM: P < 0.001; CM P < 0.001). The confidence increase in 3DPVAM trainees was noninferior to that in CM trainees (P < 0.001).ConclusionsGeneration of a custom-made 3DPVAM is feasible, producing comparable subjective training outcomes to those of CM. Custom-made 3D-printed training models, including incorporation of more complex anatomical configurations, could be used to instruct medical students in procedural skills. 相似文献
999.
Rosemary Frey Deborah Balmer Jackie Robinson Merryn Gott Michal Boyd 《Journal of pain and symptom management》2019,57(3):545-555.e1
Context
In most resource-rich countries, a large and growing proportion of older adults with complex needs will die while in a residential aged care (RAC) facility.Objectives
This study describes the impact of facility size (small/large), ownership model (profit/nonprofit) and provider (independent/chain) on resident comfort, and symptom management as reported by RAC staff.Methods
This retrospective “after-death” study collected decedent resident data from a subsample of 51 hospital-level RAC facilities in New Zealand. Symptom Management at the End-of-Life in Dementia and Comfort Assessment in Dying at End of life with Dementia (SM-EOLD and CAD-EOLD, respectively) scales were used by RAC staff who were closely associated with 217 deceased residents. Data collection occurred from January 2016 to February 2017.Results
Results indicated that residents of large, nonprofit facilities experienced greater comfort at the end of life (CAD-EOLD) as indicated by a higher mean score of 37.21 (SD = 4.85, 95% CI = 34.4, 40.0) than residents of small for-profit facilities who recorded a lower mean score of 31.56 (SD = 6.20, 95% CI = 29.6, 33.4). There was also evidence of better symptom management for residents of chain facilities, with a higher mean score for symptom management (SM-EOLD total score) recorded for residents of chain facilities (mean = 28.07, SD = 7.64, 95% CI = 26.47, 29.66) than the mean score for independent facilities (mean = 23.93, SD = 8.72, 95% CI = 21.65, 26.20).Conclusion
Findings suggest that there are differences in the quality of end-of-life care given in RAC based on size, ownership model, and chain affiliation. 相似文献1000.
Kishor Devalaraja-Narashimha Karoline Meagher Yifan Luo Cong Huang Theodore Kaplan Anantharaman Muthuswamy Gabor Halasz Sarah Casanova John OBrien Rebecca Peyser Boiarsky John McWhirter Hans Gartner Yu Bai Scott MacDonnell Chien Liu Ying Hu Adrianna Latuszek Yi Wei Srinivasa Prasad Tammy Huang George Yancopoulos Andrew Murphy William Olson Brian Zambrowicz Lynn Macdonald Lori G. Morton 《Journal of the American Society of Nephrology : JASN》2021,32(1):99