全文获取类型
收费全文 | 8603篇 |
免费 | 753篇 |
国内免费 | 352篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 230篇 |
妇产科学 | 207篇 |
基础医学 | 1462篇 |
口腔科学 | 173篇 |
临床医学 | 542篇 |
内科学 | 1002篇 |
皮肤病学 | 102篇 |
神经病学 | 245篇 |
特种医学 | 136篇 |
外国民族医学 | 2篇 |
外科学 | 1529篇 |
综合类 | 1313篇 |
现状与发展 | 1篇 |
预防医学 | 292篇 |
眼科学 | 76篇 |
药学 | 689篇 |
2篇 | |
中国医学 | 182篇 |
肿瘤学 | 1479篇 |
出版年
2024年 | 25篇 |
2023年 | 128篇 |
2022年 | 327篇 |
2021年 | 487篇 |
2020年 | 330篇 |
2019年 | 379篇 |
2018年 | 298篇 |
2017年 | 341篇 |
2016年 | 302篇 |
2015年 | 383篇 |
2014年 | 491篇 |
2013年 | 491篇 |
2012年 | 388篇 |
2011年 | 525篇 |
2010年 | 457篇 |
2009年 | 400篇 |
2008年 | 385篇 |
2007年 | 437篇 |
2006年 | 396篇 |
2005年 | 369篇 |
2004年 | 370篇 |
2003年 | 292篇 |
2002年 | 243篇 |
2001年 | 212篇 |
2000年 | 186篇 |
1999年 | 188篇 |
1998年 | 133篇 |
1997年 | 108篇 |
1996年 | 89篇 |
1995年 | 79篇 |
1994年 | 52篇 |
1993年 | 49篇 |
1992年 | 30篇 |
1991年 | 17篇 |
1990年 | 24篇 |
1989年 | 16篇 |
1988年 | 27篇 |
1987年 | 12篇 |
1986年 | 12篇 |
1985年 | 26篇 |
1984年 | 32篇 |
1983年 | 28篇 |
1982年 | 31篇 |
1981年 | 16篇 |
1980年 | 24篇 |
1979年 | 21篇 |
1978年 | 13篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 8篇 |
排序方式: 共有9708条查询结果,搜索用时 15 毫秒
41.
目的基于引入注意力机制的长短期记忆网络(long short-term memory,LSTM)和L1正则化的Logistic回归筛选变量,再通过传统的Logistic回归建立重症监护病房(intensive care unit,ICU)脑卒中患者院内死亡风险预测模型并评价模型效果。方法选取重症医学信息数据库(Medical Information Mart for Intensive Care-Ⅳ,MIMIC-Ⅳ)中的脑卒中患者作为研究对象,以是否发生院内死亡作为结局变量,备选预测因子包括人口学特征、合并症、入院48 h内实验室检查和生命体征检查等。将数据根据结局指标以8 ∶2的比例随机进行10次训练集和测试集的划分,在训练集上构建LSTM和L1正则化的Logistic回归模型,在测试集上选取重要程度排名前10的变量的并集纳入Logistic回归建立预测模型,以受试者工作特征曲线下面积(area under curve, AUC)、灵敏度、特异度、预测准确度为指标对模型进行评价,并与未预先进行变量筛选的前进法Logistic回归模型的预测效果进行比较。结果共纳入2 755例脑卒中患者的2 979条ICU入院记录,其中院内死亡记录占17.66%。两个变量筛选模型中,L1正则化的Logistic回归模型的AUC显著优于LSTM模型(0.819±0.031 vs. 0.760±0.018, P < 0.001),两个模型中重要程度均位于前10的变量包括年龄、血糖和尿素氮。最终预测模型的AUC为0.85,灵敏度为85.98%,特异度为71.74%,预测准确率为74.26%,优于未预先进行变量筛选的前进法Logistic回归模型。结论用引入注意力机制的LSTM和L1正则的Logistic回归筛选出的变量的预测效果较好,具有一定的临床价值。 相似文献
42.
目的探讨术前外周血炎症指标对舌鳞状细胞癌(TSCC)患者预后的预测价值。方法回顾性分析2010年1月至2017年12月于郑州大学第一附属医院因TSCC行根治性切除术的210例患者的临床病理资料,应用临床诊断性能曲线确定血小板/淋巴细胞比值(PLR)、中性粒细胞/淋巴细胞比值(NLR)的最佳截断值。生存单因素分析应用Kaplan-Meier法和Log-rank检验,多因素分析应用Cox比例风险回归模型,基于Cox回归模型筛选的独立危险因素构建Nomogram模型。结果单因素分析显示,PLR、NLR、肿瘤分化程度、T分期、N分期和TNM分期为影响TSCC预后的危险因素(P<0.05);多因素分析显示,PLR、N分期和TNM分期为独立危险因素(P<0.05)。Nomogram模型的C指数为0.701(95%CI:0.651~0.752),校准曲线表明Nomogram模型预测无进展生存率与实际无进展生存率具有较好的一致性。结论术前外周血炎症指标对TSCC术后患者的预后可能有一定的预测作用。 相似文献
43.
Xiaoyi Hu Qian Wang Hui Zhao Wenhui Wu Qinhua Zhao Rong Jiang Jinming Liu Lan Wang Ping Yuan 《动物模型与实验医学(英文)》2022,5(3):217
BackgroundAberrant expression of microRNAs (miRNAs) has been associated with the pathogenesis of pulmonary hypertension (PH). It is, however, not clear whether miRNAs are involved in estrogen rescue of PH.MethodsFresh plasma samples were prepared from 12 idiopathic pulmonary arterial hypertension (IPAH) patients and 12 healthy controls undergoing right heart catheterization in Shanghai Pulmonary Hospital. From each sample, 5 μg of total RNA was tagged and hybridized on microRNA microarray chips. Monocrotaline‐induced PH (MCT‐PH) male rats were treated with 17β‐estradiol (E2) or vehicle. Subgroups were cotreated with estrogen receptor (ER) antagonist or with antagonist of miRNA.ResultsMany circulating miRNAs, including miR‐21‐5p and miR‐574‐5p, were markedly expressed in patients and of interest in predicting mean pulmonary arterial pressure elevation in patients. The expression of miR‐21‐5p in the lungs was significantly upregulated in MCT‐PH rats compared with the controls. However, miR‐574‐5p showed no difference in the lungs of MCT‐PH rats and controls. miR‐21‐5p was selected for further analysis in rats as E2 strongly regulated it. E2 decreased miR‐21‐5p expression in the lungs of MCT‐PH rats by ERβ. E2 reversed miR‐21‐5p target gene FilGAP downregulation in the lungs of MCT‐PH rats. The abnormal expression of RhoA, ROCK2, Rac1 and c‐Jun in the lungs of MCT‐PH rats was inhibited by E2 and miR‐21‐5p antagonist.ConclusionsmiR‐21‐5p level was remarkably associated with PH severity in patients. Moreover, the miR‐21‐5p/FilGAP signaling pathway modulated the protective effect of E2 on MCT‐PH through ERβ. 相似文献
44.
目的观察一次性皮肤拉拢装置治疗难闭性皮肤软组织缺损的疗效。方法回顾分析2021年7月—2022年2月符合选择标准的13例采用一次性皮肤拉拢装置治疗的难闭性皮肤软组织缺损患者临床资料。其中男9例,女4例;年龄15~71岁,平均39.8岁。致伤原因:摔伤5例,交通事故伤5例,高处坠落伤3例。皮肤软组织缺损原因:开放骨折4例,伤口感染4例,骨髓炎3例,脱套伤1例,植皮坏死1例。损伤部位:小腿8例,跟骨3例,骨盆1例,足底1例。皮肤软组织缺损范围为5.0 cm×2.0 cm~10.5 cm×6.5 cm。记录伤口情况(包括伤口闭合和伤口愈合)及有无并发症等情况。结果13例患者均获随访,随访时间32~225 d,中位时间164 d。伤口闭合时间5~14 d,平均8.8 d;伤口闭合速度0.7~13.7 cm2/d,平均3.6 cm2/d。所有伤口均甲级愈合,均未发生皮缘损伤、伤口坏死、感染、裂开、水肿等并发症,患者均未诉疼痛不适等,随访时未发现明显瘢痕形成等情况。伤口愈合时间17~28 d,平均21.7 d。其中1例使用该装置后因肺癌病情变化转科,术后17 d随访时伤口未经缝合已直接愈合。 结论一次性皮肤拉拢装置治疗难闭性皮肤软组织缺损疗效确切,伤口闭合时间短,并发症少,操作简便。 相似文献
45.
Breast cancer (BC) is the most common malignancy among women in Canada. Adjuvant treatment in early BC can reduce the risk of BC recurrence. Historically, the decision for adjuvant chemotherapy for early BC was made only based on clinical and tumour characteristics. In recent years, there has been an effort toward developing genomic assays as a predictive and prognostic tool to improve precision in estimating disease recurrence, sensitivity to systemic treatment and ultimately with clinical utility for guidance regarding adjuvant systemic treatment(s). There are various commercial genomic tests available for early-stage ER+/HER-2 negative BC. This paper will review the Oncotype DX 21-gene Recurrence Score (RS), MammaPrint, EndoPredict, Prosigna®, and Breast Cancer Index (BCI) genomic assays. We will also focus on these genomic assays’ clinical application and utility in node-positive early-stage BC based on the most recent evidence and guidance recommendations. 相似文献
46.
Xiaoxi Lv Chang Liu Shanshan Liu Yunxuan Li Wanyu Wang Ke Li Fang Hua Bing Cui Xiaowei Zhang Jiaojiao Yu Jinmei Yu ZhuoWei Hu 《药学学报(英文版)》2022,12(2):735-746
The cell cycle inhibitor P21 has been implicated in cell senescence and plays an important role in the injury–repair process following lung injury. Pulmonary fibrosis (PF) is a fibrotic lung disorder characterized by cell senescence in lung alveolar epithelial cells. In this study, we report that P21 expression was increased in alveolar epithelial type 2 cells (AEC2s) in a time-dependent manner following multiple bleomycin-induced PF. Repeated injury of AEC2s resulted in telomere shortening and triggered P21-dependent cell senescence. AEC2s with elevated expression of P21 lost their self-renewal and differentiation abilities. In particular, elevated P21 not only induced cell cycle arrest in AEC2s but also bound to P300 and β-catenin and inhibited AEC2 differentiation by disturbing the P300–β-catenin interaction. Meanwhile, senescent AEC2s triggered myofibroblast activation by releasing profibrotic cytokines. Knockdown of P21 restored AEC2-mediated lung alveolar regeneration in mice with chronic PF. The results of our study reveal a mechanism of P21-mediated lung regeneration failure during PF development, which suggests a potential strategy for the treatment of fibrotic lung diseases. 相似文献
47.
BackgroundLung cancer is one of the most common malignancies globally and a significant component of cancer‐related deaths. The lack of early diagnosis accounts for detecting approximately 75% of cancer patients at an intermediate to an advanced stage, with a low 5‐year survival rate. Therefore, a more comprehensive understanding of the molecular mechanisms of lung cancer development is necessary to find reliable and effective therapeutic and diagnostic biomarkers.Methodscirc_SAR1A, miR‐21‐5p, and TXNIP in lung cancer tissues, animal xenografts, and cell lines were validated by qRT‐PCR and western blotting analyses. RNase R digestion and nuclear/cytoplasm fractionation experiments were utilized to determine the stability and localization of circ_SAR1A in lung cancer cells. The binding between miR‐21‐5p and circ_SAR1A or TXNIP was confirmed by luciferase reporter, RNA pull‐down, Spearman''s correlation, and rescue assays. CCK‐8, colony formation, flow cytometry, Transwell, and western blotting were utilized to illustrate the malignant behavior of lung cancer cells.Resultscirc_SAR1A and TXNIP were down‐regulated while miR‐21‐5p was up‐regulated in lung cancer samples and cells. circ_SAR1A was located predominantly in the cytoplasm; it inhibited lung cancer growth in vitro and in vivo by sponging to miR‐21‐5p. miR‐21‐5p silencing suppressed lung cancer malignancy by targeting TXNIP.Conclusionscirc_SAR1A is a critical negative regulator of lung carcinogenesis. circ_SAR1A/miR‐21‐5p/TXNIP attenuation inhibited lung cancer progression, presenting an ideal diagnostic and a potential therapeutic target. 相似文献
48.
In the case of a previous offspring with trisomy 21, recurrence risk for Down syndrome is about 1%. It may be due to chance, but the possibility of germline mosaicism for trisomy 21 in one of the parents has important implications for the recurrence. Here we report a young healthy mother, who has a second pregnancy of trisomy 21.[第一段] 相似文献
49.
目的构建稳定过表达硫氧还蛋白还原酶1(TrxR1)的HEK293细胞株,为TrxR1的功能研究以及靶向TrxR1药物筛选提供细胞模型。方法通过PCR扩增,连接转化以及Sanger双脱氧测序构建并筛选出TrxR1的重组慢病毒表达载体pLVX-PuroTXNRD1,转染HEK293细胞,经嘌呤霉素筛选获得稳定转染细胞株。后续研究分为3组进行:①TrxR1过表达HEK293细胞:pLVX-Puro-TXNRD1载体稳定转染细胞;②对照HEK293细胞:pLVX-Puro空载病毒载体稳定转染细胞;③正常HEK293细胞;通过RT-qPCR、Western blot实验检测上述3组细胞中TrxR1的mRNA以及蛋白表达情况;通过胰岛素终点法以及TRFS-green探针成像检测上述3种细胞内TrxR1的酶活力;通过CCK8实验检测上述3种细胞对TrxR1特异性抑制剂auranofin的敏感性。结果构建载体经DNA测序,成功获得插入TrxR1的重组慢病毒表达载体pLVX-Puro-TXNRD1。与HEK293以及HEK293-NC细胞相比,HEK293-TrxR1-OE细胞中TrxR1的mRNA和蛋白高表达,且酶活力也同样显著上升(P<0.005);而与HEK293以及HEK293-NC细胞相比,auranofin对HEK293-TrxR1-OE细胞中TrxR1酶活力以及细胞增殖的抑制效率均显著下降(P<0.005)。结论通过构建pLVX-Puro-TXNRD1慢病毒载体,成功获得过表达TrxR1酶的HEK293细胞株,该细胞对特异性靶向TrxR1的抑制剂的抗增殖作用具有抵抗,因而可用于靶向TrxR1药物的筛选。 相似文献
50.
目的构建和验证腹膜透析相关性腹膜炎(PDAP)患者治疗失败的风险预测模型。方法对2013年1月1日~2019年12月31日在吉林省3个腹膜透析中心发生PDAP的腹膜透析(PD)患者进行了回顾性分析。收集入选者基线临床资料,主要研究终点为治疗失败。根据腹膜透析中心地域的不同,将数据分为训练集(吉林大学第二医院、吉林大学第一医院二部)和验证集(吉林市中心医院)。采用Logistic风险回归模型筛选影响PDAP治疗失败的危险因素,用Stata建立预测模型;用ROC曲线和校准曲线评估模型的区分度和准确性,并以DCA曲线评估列线图的临床有效性。结果共纳入977例次PDAP,训练集中625例次,其中78例治疗失败,验证集中352例次,其中35例治疗失败。建模队列多因素Logistic回归分析结果显示,血清白蛋白、第5天腹透液白细胞计数、透析龄和致病微生物类型是治疗失败的独立危险因素,在训练集中的C统计量为0.827(95% CI:0.784–0.871)。在验证集中,C统计量为0.825(95%CI:0.743-0.908)。预测模型在训练和验证集的校准方面都表现良好。结论基于血清白蛋白、第5天腹透液白细胞计数、透析龄和致病微生物类型构建了预测模型,性能良好。 相似文献