全文获取类型
收费全文 | 11785篇 |
免费 | 907篇 |
国内免费 | 235篇 |
专业分类
耳鼻咽喉 | 129篇 |
儿科学 | 140篇 |
妇产科学 | 108篇 |
基础医学 | 2008篇 |
口腔科学 | 192篇 |
临床医学 | 1388篇 |
内科学 | 1389篇 |
皮肤病学 | 126篇 |
神经病学 | 687篇 |
特种医学 | 567篇 |
外国民族医学 | 3篇 |
外科学 | 587篇 |
综合类 | 1356篇 |
预防医学 | 1549篇 |
眼科学 | 182篇 |
药学 | 1452篇 |
15篇 | |
中国医学 | 292篇 |
肿瘤学 | 757篇 |
出版年
2023年 | 249篇 |
2022年 | 283篇 |
2021年 | 511篇 |
2020年 | 584篇 |
2019年 | 410篇 |
2018年 | 347篇 |
2017年 | 405篇 |
2016年 | 441篇 |
2015年 | 470篇 |
2014年 | 871篇 |
2013年 | 823篇 |
2012年 | 735篇 |
2011年 | 822篇 |
2010年 | 603篇 |
2009年 | 601篇 |
2008年 | 603篇 |
2007年 | 527篇 |
2006年 | 438篇 |
2005年 | 403篇 |
2004年 | 353篇 |
2003年 | 311篇 |
2002年 | 265篇 |
2001年 | 224篇 |
2000年 | 157篇 |
1999年 | 130篇 |
1998年 | 117篇 |
1997年 | 105篇 |
1996年 | 82篇 |
1995年 | 106篇 |
1994年 | 105篇 |
1993年 | 66篇 |
1992年 | 81篇 |
1991年 | 70篇 |
1990年 | 69篇 |
1989年 | 49篇 |
1988年 | 59篇 |
1987年 | 62篇 |
1986年 | 33篇 |
1985年 | 70篇 |
1984年 | 61篇 |
1983年 | 47篇 |
1982年 | 38篇 |
1981年 | 34篇 |
1980年 | 34篇 |
1979年 | 18篇 |
1978年 | 8篇 |
1977年 | 6篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1974年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Mathew Vithayathil Scott Smith Mingyang Song 《International journal of cancer. Journal international du cancer》2023,152(6):1085-1094
Serrated polyps (SPs) are precursors to one-third of colorectal cancers (CRCs), with histological subtypes: hyperplastic polyps (HPs), sessile serrated lesions (SSLs) and traditional serrated adenomas (TSAs). The incidence of early-onset CRC before the age of 50 is increasing, with limited understanding of SPs in younger cohorts. Using a large colonoscopy-based cohort, we characterized epidemiologic profiles of SP subtypes, compared to conventional adenomas, with secondary analysis on early-onset polyps. Ninety-four thousand four hundred and twenty-seven patients underwent screening colonoscopies between 2010 and 2018. Demographic, endoscopic and histopathologic characteristics of each polyp subtype were described. High-risk polyps included SSLs ≥10 mm/with dysplasia and conventional adenomas ≥10 mm/with tubulovillous/villous histology/high-grade dysplasia. We examined polyp prevalence with age and compared early- (age < 50) and late-onset polyps (age ≥ 50). Eighteen thousand one hundred and twenty-five patients had SPs (4357 SSLs, 15 415 HPs, 120 TSAs) and 26 699 had conventional adenomas. High-risk SSLs were enriched in the ascending colon (44.1% vs 2.6-35.8% for other locations; P < .003). Early- and late-onset SPs had similar subsite distribution. Early-onset conventional adenomas were more enriched in the distal colon/rectum (51.8% vs 43.4%, P < .001). Multiple conventional adenomas were more represented in late-onset groups (40.8% vs 33.8%, P < .001), with no difference in SSLs. The prevalence of conventional adenomas/high-risk conventional adenomas increased continuously with age, whereas the prevalence of SSLs/high-risk SSLs was stable from age 40 years onwards. A higher proportion of women were diagnosed with early-onset than late-onset SSLs (62.9% vs 57.6%, P = .03). Conventional adenomas, SSLs, early- and late-onset polyps have distinct epidemiology. The findings have implications for improved colonoscopy screening and surveillance and understanding the etiologic heterogeneity of CRC. 相似文献
2.
目的 比较龋蚀检知液Caries detector和10% 优碘对离体牙龋坏牙体组织的检测效果,为临床应用提供实验室依据。 方法 选择有龋坏的离体牙80颗,分为Caries detector组和10% 优碘组,每组各40颗,再按龋坏深度分为Caries detector浅龋组,Caries detector深龋组,10%优碘浅龋组及10%优碘深龋组,每组20颗。分别记录各离体牙原始质量为G1,使用挖匙去腐后,再次记录各离体牙质量为G2,分别涂布Caries detector与10%优碘,使用挖匙去腐后再次记录离体牙质量为G3。观察各组腐质去除情况,计算并比较各组腐质清除率。 结果 Caries detector或是10%优碘都有明显的染色效果,Caries detector的染色范围大于10%优碘,并且在清除染色牙本质后仍有不易移除的残留染剂在更深层的牙本质中。Caries detector浅龋组腐质清除率高于10%优碘浅龋组,差异有统计学意义(P<0.05); Caries detector深龋组染色后腐质清除率高于10%优碘深龋组,差异有统计学意义(P<0.001)。 结论 Caries detector在浅龋的腐质去除上有着卓越的染色效果,但是对于患有深龋的牙齿,建议使用10%的优碘,会有较好的效果。 相似文献
3.
目的研究免疫学检验联合检测诊断类风湿关节炎(RA)的临床价值。方法40例进行体检的健康人员作为参照组,同期40例类风湿关节炎患者作为研究组。两组受检者均接受免疫学检验联合检测,分析检验结果。比较两组类风湿因子(RF)、抗环瓜氨酸多肽抗体(抗CCP)、抗角蛋白抗体(AKA)阳性检出率,免疫球蛋白G(IgG)、补体C3、补体C4水平。结果研究组的RF、抗CCP、AKA阳性检出率分别为85.00%、62.50%、85.00%,均高于参照组的2.50%、5.00%、0,差异具有统计学意义(P<0.05)。研究组的IgG为(15.64±4.71)g/L、补体C3为(0.68±0.25)g/L、补体C4为(0.14±0.05)g/L,参照组的IgG为(10.47±3.08)g/L、补体C3为(1.23±0.31)g/L、补体C4为(0.29±0.17)g/L。研究组的IgG高于参照组,补体C3、补体C4低于参照组,差异具有统计学意义(P<0.05)。结论采用免疫学检验联合检测诊断类风湿关节炎的准确率较高,临床可以将其作为类风湿关节炎诊断的有效方案,为患者的疾病治疗提供参考。 相似文献
4.
5.
《Archivos de bronconeumología》2022,58(5):406-411
IntroductionLung cancer (LC) is usually diagnosed at advanced stages with only a 12% 5-year survival. Trials as NLST and NELSON show a mortality decrease, which justifies implementation of lung cancer screening in risk population. Our objective was to show survival results of the largest LC screening program in Spain with low dosage computed tomography (LDCT).MethodsClinical records from International Early Lung Cancer Detection Program (IELCAP) at Valencia, Spain were analysed. This program recruited volunteers, ever-smokers aged 40-80 years, since 2008. Results are compared to those from other similar sizeable programs.ResultsA total of 8278 participants were screened with at least two-rounds until November 2020. A mean of 6 annual screening rounds were performed. We detected 239 tumours along 12-year follow-up. Adenocarcinoma was the most common histology, being 61.3% at stage I. The lung cancer prevalence and incidence proportion was 1.5% and 1.4%, respectively with an annual detection rate of 0.17. One-year survival and 10-year survival were 90% and 80.1%, respectively. Adherence was 96.84%.ConclusionLargest lung cancer screening in Spain shows that survival is improved when is performed in multidisciplinary team experienced in management of LC, and is comparable to similar screening programs. 相似文献
6.
背景:肺是原发性肺癌,乳腺癌,肝癌,结直肠癌、食管癌转移的目标器官之一。尽管计算机断层扫描(CT)是检查肺部转移最广泛的应用方法,但发现早期的肺转移灶仍具有非常大的挑战性。如果能在最早的时间点上,经胸部CT扫描而发现肺转移,可能会改变癌症的分期,并且该信息可能会影响临床治疗决策,将使患者受益。本研究的目的是探究CT扫描是否可以在比当前更早的时间节点上发现肺转移。
方法:于2016年1月至2020年1月随机选择120例肺转移患者的CT检查影像及临床病史资料,并回顾性分析扫描结果。这120例患者患有原发性肺癌、食道癌、肠癌及肝癌。经过后来CT扫描证实有肺部转移的患者均进行了多次胸部CT检查(包括术前胸部CT)。检查早期的CT扫描以确定是否在相同位置的肺转移灶已被诊断或漏诊。根据原发癌的类型和邻近血管的分类对肺转移的漏诊进行统计分析。
结果:漏诊的肺转移病例为42/120(35%),其中单发转移为21例,多发转移为21例。遗漏转移的地方,在肺段区域中分布有统计学差异(P <0.01)。临近血管、胸膜或叶间裂似乎是漏诊肺转移的重要因素(P <0.01)。
结论:在CT扫描中出现的早期肺转移有相当一部分被放射科医生漏诊。通过培训改进以及技术发展(例如计算机辅助检测),CT扫描可以在更早的时间节点上诊断出肺转移,为临床治疗方案制定提供依据,从而使患者受益。 相似文献
7.
提出一种面向医院患者的视觉监控跌倒检测算法,解决患者由于意外跌倒不能被及时发现的问题,为医护人员快速处理患者跌倒等异常行为提供必要的技术保障。方法:首先,基于深度神经网络模型检测监控图像中人体关节点(如肩部、肘部、腕部、胯部、膝关节等)在图像中的位置,再根据亲和度向量场模型提取人体骨架,最后计算患者躯干、腿部与地面的夹角作为判别性特征,判断监控区域内是否有患者出现意外跌倒。结果:实验结果表明,本文所提算法在实际的医院监护环境中的处理速度高达25帧/s,检测准确率高达96%。结论:该方法能够实时、准确地提取医院环境下患者的行为特征,并针对意外跌倒情况发出警报,为医护人员监测患者跌倒等异常行为提供更准确、方便的计算机辅助医疗护理方法。 相似文献
8.
[摘要]?目的?结合环介导等温扩增技术(loop-mediated isothermal amplification, LAMP)和微流控芯片技术,建立一种适合现场快速检测登革病毒的方法。方法?利用RT-LAMP,针对登革病毒基因组中3’非编码区中特异性序列进行扩增,建立基于微流控芯片技术的LAMP检测方法,优化检测体系,并对该方法的灵敏性和特异性进行评估。结果?基于LAMP 和微流控芯片技术的登革病毒检测方法,通过对病毒模板进行扩增,发现与其他病毒无交叉反应,特异性良好;同时,结果显示该方法对登革病毒检测灵敏性可达61.2 pg/μl,与实时荧光定量PCR仪所达到的检测灵敏性一致。结论?基于LAMP和微流控芯片技术的登革病毒检测方法具有操作简单、快速、对设备要求低等优势,并且灵敏性、特异性均较好,是一种便于开展现场快速检测的方法。 相似文献
9.
目的 建立一种简单,快速的重组酶聚合酶核酸扩增技术检测鼠疫耶尔森氏菌的方法。方法 基于耶尔森氏菌的特异性序列设计引物及探针;通过对不同温度的检测来优化反应温度;通过对不同菌株的DNA模板进行检测评价该方法的特异性;通过对不同稀释浓度的样本DNA模板进行检测来确定灵敏性;通过模拟样品进行应用评价。结果 基于鼠疫耶尔森菌的DNA腺嘌呤甲基化酶基因设计特异性引物和探针所建立的荧光重组酶聚合酶扩增方法,35 ℃反应20 min内可成功检出低至100个拷贝的鼠疫耶尔森菌基因,而且与其他菌无交叉反应,对模拟样品的检测准确性达到98.0%。结论 重组酶聚合酶核酸扩增可广泛应用于简陋条件下鼠疫耶尔森菌的临床检测,促进鼠疫的防控。 相似文献
10.
《Journal of thoracic oncology》2022,17(1):56-66
Screening with low-dose computed tomography of high-risk individuals with a smoking history reduces lung cancer mortality. Current screening guidelines and eligibility criteria can miss more than 50% of lung cancers, and in some geographic areas, such as East Asia, a large proportion of the missed lung cancers are in never-smokers. Although randomized trials revealed the benefits of screening for people who smoke, these trials generally excluded never-smokers. Thus, the feasibility and effectiveness of lung cancer screening of individuals who never smoked are uncertain. Several known and suspected risk factors for lung cancers in never-smokers such as exposure to secondhand smoke, occupational carcinogens, radon, air pollution, and pulmonary diseases, such as chronic obstructive pulmonary disease and interstitial lung diseases, and intrinsic factors, such as age, are well noted. In this regard, knowledge of risk factors may make possible quantification and prediction of lung cancer risk in never smokers. It is worth considering if and how never smokers could be included in population-based screening programs. As the implementation of these programs is challenging in many countries owing to multiple factors and the epidemiologic differences by global regions, these issues will need to be evaluated in each country taking into account various factors, including accuracy of risk assessment and cost-effectiveness of screening in never smokers. This report aims to outline current knowledge on risk factors for lung cancer in never smokers to propose research strategies for this topic and initiate a broader discussion on lung cancer screening of never smokers. Similar considerations can be made in current and ex-smokers, which do not fulfill the current screening inclusion criteria, but otherwise are at increased risk. Although screening of never smokers may in the future be effectively conducted, current evidence to support widespread implementation of this practice is lacking. 相似文献