全文获取类型
收费全文 | 275715篇 |
免费 | 24135篇 |
国内免费 | 16990篇 |
专业分类
耳鼻咽喉 | 2542篇 |
儿科学 | 3333篇 |
妇产科学 | 5148篇 |
基础医学 | 31450篇 |
口腔科学 | 4774篇 |
临床医学 | 35015篇 |
内科学 | 43896篇 |
皮肤病学 | 3179篇 |
神经病学 | 14973篇 |
特种医学 | 10027篇 |
外国民族医学 | 105篇 |
外科学 | 30795篇 |
综合类 | 41483篇 |
现状与发展 | 60篇 |
一般理论 | 47篇 |
预防医学 | 17832篇 |
眼科学 | 7416篇 |
药学 | 28056篇 |
195篇 | |
中国医学 | 13503篇 |
肿瘤学 | 23011篇 |
出版年
2024年 | 893篇 |
2023年 | 4194篇 |
2022年 | 10312篇 |
2021年 | 13458篇 |
2020年 | 10015篇 |
2019年 | 8761篇 |
2018年 | 9178篇 |
2017年 | 8207篇 |
2016年 | 7721篇 |
2015年 | 11775篇 |
2014年 | 14674篇 |
2013年 | 14036篇 |
2012年 | 20382篇 |
2011年 | 22263篇 |
2010年 | 13971篇 |
2009年 | 11273篇 |
2008年 | 14812篇 |
2007年 | 14837篇 |
2006年 | 14133篇 |
2005年 | 14070篇 |
2004年 | 9651篇 |
2003年 | 8501篇 |
2002年 | 7367篇 |
2001年 | 6578篇 |
2000年 | 6628篇 |
1999年 | 6887篇 |
1998年 | 3890篇 |
1997年 | 3906篇 |
1996年 | 2968篇 |
1995年 | 2748篇 |
1994年 | 2371篇 |
1993年 | 1558篇 |
1992年 | 2369篇 |
1991年 | 2073篇 |
1990年 | 1740篇 |
1989年 | 1510篇 |
1988年 | 1312篇 |
1987年 | 1207篇 |
1986年 | 961篇 |
1985年 | 758篇 |
1984年 | 506篇 |
1983年 | 383篇 |
1982年 | 235篇 |
1981年 | 211篇 |
1980年 | 192篇 |
1979年 | 249篇 |
1978年 | 152篇 |
1977年 | 117篇 |
1976年 | 100篇 |
1974年 | 120篇 |
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
981.
982.
目的:探讨影像组学方法在术前预测直肠非黏液性腺癌淋巴结转移中的价值。方法:回顾性分析91例手术病理切片证实为直肠非黏液性腺癌患者的影像学资料,其中61例为训练样本,30例为验证样本。基于全瘤体积,从每个原发病灶术前高分辨T2加权成像(T2-weighted imaging,T2WI)图像中提取影像组学特征1 301个。基于训练样本,利用最小绝对收缩和选择算子(the least absolute shrinkage and selection operator,LASSO)逻辑回归方法筛选关键特征并构建影像组学分类器。采用受试者工作特征(receiver operating characteristic,ROC)曲线评价影像组学分类器的辨别效能,并将其与形态学标准进行比较。在验证样本中验证影像组学分类器的价值。结果:由5个影像组学特征构建的分类器与淋巴结转移状态有关(P<0.001)。在训练样本和验证样本中,影像组学分类器诊断淋巴结转移的曲线下面积分别为0.874(95% CI:0.787~0.960)和0.878(95% CI:0.727~1.000),形态学标准诊断淋巴结转移的曲线下面积分别为0.619(95% CI:0.487~0.752)和0.556(95% CI:0.355~0.756)。无论是训练样本还是验证样本,影像组学分类器的诊断效能均高于形态学标准(均P<0.05)。结论:影像组学分类器可术前个体化预测直肠非黏液性腺癌淋巴结转移,而且其诊断效能高于形态学标准。 相似文献
983.
血小板的种系发生提示其在免疫炎症中起重要作用,近年来发现血小板活化与炎症性肠病的活动性密切
相关,活化的血小板可以释放炎症介质,表达介导炎症反应的表面分子,可与白细胞和内皮细胞发生相互作用,这
为抗血小板药物治疗炎症性肠病提供了理论依据。 相似文献
984.
目的 建立同时测定四逆散水提液中16种化学成分含量的方法。方法 应用UHPLC-QqQ-MS技术,采用负离子模式进行扫描,以MRM配对离子方式进行定量。结果 柴胡皂苷A、柴胡皂苷B2、柴胡皂苷C、柴胡皂苷D、橙皮素、儿茶素、甘草苷、甘草酸、甘草素、绿原酸、没食子酸、芍药苷、芍药内酯苷、异甘草素、异绿原酸A、橙皮苷在负离子模式下响应良好。结论 本实验所建立的同时测定四逆散水提液中16种化学成分含量的分析方法专属性强、快速、灵敏且准确可靠,在完成含量测定的同时又可以准确给出化合物质量数信息,从而达到成分鉴别的效果,该方法可以为四逆散水提液的全面质量控制提供技术支持。 相似文献
985.
Association between interleukin-10 genetic polymorphisms and risk of primary open angle glaucoma in a Chinese Han population: a case-control study 下载免费PDF全文
AIM: To investigate the association between interleukin-10 (IL-10) genetic polymorphisms and risk of POAG through a case-control study in a Han population of China.
METHODS: A total of 210 patients with POAG and 420 normal subjects were recruited during the period from Dec. 2013 to Dec. 2016. The IL-10 -1082A>G (rs1800870), -819T>C (rs1800871) and -592C>A (rs1800872) polymorphisms were determined using iPlex GOLD SNP genotyping analysis (the SequenomMassARRAY® System, Sequenom, San Diego, USA). The association between IL-10 -1082A>G (rs1800870), -819T>C (rs1800871), and -592C>A (rs1800872) polymorphisms and risk of POAG was assessed by singlelogistic regression analysis.
RESULTS: We observed that those carrying the CC genotype of rs1800871 was associated with an increased risk of POAG when compared with those harboring the TT genotype (OR=1.84, 95%CI=1.01-3.38). Those with AA genotype of rs1800872 had a 10.62 fold risk of POAG in comparison to the CC genotype (OR=10.62, 95%CI, 3.41-33.09). A completely linkage disequilibrium was found between IL-10 rs1800871-rs1800872 (D’=1.00, r2=0.16). The A-C-A (OR=2.60, 95%CI, 1.48-4.58) and G-T-A (OR=2.34, 95%CI, 1.42-3.86) haplotypes were associated with an increased risk of POAG, while the A-T-C haplotype showed a decreased risk of POAG (OR=0.63, 95%CI, 0.49-0.81).
CONCLUSION: Our data suggest that IL-10 rs1800871 and rs1800872 can be predictive factors for the pathogenesis of POAG in the Chinese population. 相似文献
986.
目的 观察改良可视双腔支气管导管(Visual Double-Lumen Tube,VDLT)塑形方法在胸外科手术单肺通气中的应用效果。方法 选取2020-08至2021-08我院胸外科择期手术单肺通气患者60例,美国麻醉医师协会(American Society of Anesthesiologists,ASA)分级I~Ⅲ级,年龄24~80岁,性别不限,BMI 19~28 kg/m2。采用随机数字表法将患者分为传统塑形组(Tsaditional Shaping,TS组)和改良塑形组(Isproved Shaping,IS组),每组30例。记录麻醉诱导前(T1)、麻醉诱导后即刻(T2)、插管后1 min(T3)的心率(Heart Rate,HR)及平均动脉血压(Mean Arterial Pressure,MAP);记录插管时间、插管次数、支气管定位情况;记录术后咽喉部疼痛、声音嘶哑等并发症情况。结果 TS组插管时间(67.1±23.8)s明显长于IS组(38.9±10.0)s;TS组插管次数1.3±0.4次明显多于IS组1.0±0.0次(P<0.05),两组可视双腔支气管导管支... 相似文献
987.
Hui Qiu Qing-Gong Ma Xue-Ting Chen Xin Wen Nie Zhang Wan-Ming Liu Ting-Ting Wang Long-Zhen Zhang 《American journal of cancer research》2022,12(7):3175
It has been reported that antibiotics (ATBs) have adverse effect on the efficacy of treatment with immune checkpoint inhibitors (ICIs) in cancer patients. Since different classes of ATBs have different antibacterial spectrum, we aimed to study whether all ATBs had similar or different negative effects on the clinical outcomes of ICIs in patients with advanced non-small cell lung cancer (NSCLC). Patients with advanced NSCLC who received ICIs were included in this retrospective study and grouped by the class of ATBs they had used around the ICIs treatment time. The overall survival (OS) and the progression free survival (PFS) of patients among these groups were compared using Kaplan-Meier method and Cox proportional hazards model. A total of 148 eligible patients were enrolled, and 80 patients used ATBs. The results indicated that quinolones had no significant negative consequence on the clinical outcomes, while β-lactams significantly shortened the OS and PFS of patients. Furthermore, patients exposed to the combination of β-lactams and quinolones suffered the worst OS and PFS. Moreover, the subgroup analysis of β-lactams revealed that only penicillins, but not carbapenems and cephalosporins, markedly reduced both OS and PFS. In addition to the class of ATBs used, the time frame of ATBs used also affected the clinical outcomes of ICIs therapy. Patients receiving ATBs within 60 days prior to and 30 days after the initiation of ICI treatment had significantly shorter OS and PFS compared with those who did not use ATBs. This study demonstrated that different classes of ATBs had disparate negative impacts on the clinical outcomes, and the use of β-lactams, especially penicillins, should be avoided in advanced NSCLC patients who are receiving or scheduled to receive ICIs within 60 days. 相似文献
988.
989.
目的:探讨L型氨基酸转运蛋白1(L-type amino acid transporter 1,LAT)表达水平与非肌层浸润性膀胱癌患者术后复发风险的相关性。方法:选取2021年2月至2022年2月于重庆医科大学附属永川医院接受手术治疗的非肌层浸润性膀胱癌患者108例作为研究对象,采用反转录酶聚合酶链反应测定膀胱癌组织(取自肿瘤所在部位区域)和癌旁组织(取自邻近正常区域组织)LAT1表达含量,对比膀胱癌组织和癌旁组织LAT1表达水平。同时根据膀胱癌组织LAT1表达含量的二分位数将所有患者分为高表达组和低表达组,对比2组临床病理参数。随访观察12个月观察2组术后复发情况,采用Kaplan-Meier曲线分析对比2组术后复发风险,使用多变量Cox比例风险回归模型确定术后复发的影响因素。结果:膀胱癌组织LAT1表达水平(1.80±0.35)较配对的癌旁组织LAT1表达水平(1.05±0.17)高(P<0.05);LAT1高表达组吸烟史、临床分期T1占比较LAT1低表达组高(P<0.05);108例膀胱肿瘤患者术后的平均随访时间为(10.84±1.94)个月,... 相似文献
990.
Jiajia Chen Chunshuai Wu Hongxiang Hong Xiangyu Wang Jinlong Zhang Pengfei Xue Jiawei Jiang Dan Wang Zhiming Cui 《Orthopaedic Surgery》2022,14(8):1630
ObjectiveTo translate the original English version of the Spinal Instability Neoplastic Score (SINS) into simplified Chinese, adapt it cross‐culturally, validate its psychometric properties in measuring spinal instability in patients with metastatic spinal tumors in the Chinese mainland, examine the reliability and validity to demonstrate its accuracy and applicability in clinical practice.MethodsPatients diagnosed with metastatic spinal disease between January 2016 and January 2020 were recruited. The number of participants was advised to be at least 50 for appropriate analysis of reliability, construct validity, as well as ceiling or floor effects, and recruitment of 100 patients was advised for internal consistency analysis. The study was conducted in two phases: first, the SINS was translated into simplified Chinese; second, the factor structure, internal consistency, test–retest reliability, validity, and floor and ceiling effects of the SC‐SINS were assessed. The internationally recognized cross‐cultural adaptation guidelines were followed. Internal consistency was evaluated with Cronbach''s alpha. Test–retest reliability was examined among the patients with a 4‐week interval. The validity of the Chinese version of SINS (SC‐SINS) was assessed by examining its relationship with Kostuik classification. Principal component analysis was conducted to confirm the factor structure of each subscale.ResultsA total of 160 participants (88 males and 72 females) were enrolled. No major difficulties occurred in the forward and backward translations of SINS. The internal consistency of SC‐SINS was excellent (Cronbach''s α =0.857, ranging from 0.68 to 0.85). Test–retest reliability was also excellent with a value of 0.89, ranging from 0.86 to 0.95. Validity analyses indicated that the SC‐SINS was positively and significantly correlated with Kostuik classification. The correlation between “Posterolateral Involvement of Spinal Elements” and “1‐2 Partial Damage” was the highest with a correlation value of 0.792. The correlation between “Pain” and “1–2 Partial Damage” was the lowest with a value of 0.341. All items showed principal component coefficients greater than 0.4. The values of Factor 1 ranged from 0.523 to 0.681; Factor 2 ranged from 0.591 to 0.731; Factor 3 ranged from 0.613 to 0.754; Factor 4 ranged from 0.461 to 0.711; Factor 5 ranged from 0.513 to 0.701; and Factor 6 ranged from 0.501 to 0.668. In addition, neither floor nor ceiling effects were seen in the SC‐SINS.ConclusionThe SC‐SINS demonstrated high internal consistency and test–retest reliability, which has been proven valid and reliable to measure spinal stability in patients from the Chinese mainland with metastatic spinal tumor. 相似文献