全文获取类型
收费全文 | 44903篇 |
免费 | 3841篇 |
国内免费 | 2131篇 |
专业分类
耳鼻咽喉 | 151篇 |
儿科学 | 375篇 |
妇产科学 | 215篇 |
基础医学 | 3607篇 |
口腔科学 | 548篇 |
临床医学 | 4500篇 |
内科学 | 7755篇 |
皮肤病学 | 578篇 |
神经病学 | 1834篇 |
特种医学 | 1230篇 |
外国民族医学 | 41篇 |
外科学 | 5320篇 |
综合类 | 8383篇 |
现状与发展 | 3篇 |
一般理论 | 1篇 |
预防医学 | 2836篇 |
眼科学 | 646篇 |
药学 | 4719篇 |
43篇 | |
中国医学 | 2441篇 |
肿瘤学 | 5649篇 |
出版年
2024年 | 99篇 |
2023年 | 737篇 |
2022年 | 1155篇 |
2021年 | 1722篇 |
2020年 | 1552篇 |
2019年 | 1407篇 |
2018年 | 1310篇 |
2017年 | 1587篇 |
2016年 | 1747篇 |
2015年 | 1747篇 |
2014年 | 2778篇 |
2013年 | 3476篇 |
2012年 | 2545篇 |
2011年 | 2849篇 |
2010年 | 2192篇 |
2009年 | 2101篇 |
2008年 | 2174篇 |
2007年 | 2273篇 |
2006年 | 1969篇 |
2005年 | 1884篇 |
2004年 | 1517篇 |
2003年 | 1344篇 |
2002年 | 1187篇 |
2001年 | 1228篇 |
2000年 | 1036篇 |
1999年 | 834篇 |
1998年 | 787篇 |
1997年 | 664篇 |
1996年 | 584篇 |
1995年 | 605篇 |
1994年 | 548篇 |
1993年 | 431篇 |
1992年 | 383篇 |
1991年 | 367篇 |
1990年 | 336篇 |
1989年 | 295篇 |
1988年 | 275篇 |
1987年 | 216篇 |
1986年 | 140篇 |
1985年 | 126篇 |
1984年 | 133篇 |
1983年 | 89篇 |
1982年 | 80篇 |
1981年 | 72篇 |
1980年 | 69篇 |
1979年 | 49篇 |
1978年 | 44篇 |
1977年 | 40篇 |
1976年 | 33篇 |
1975年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
目的探究老年胃癌患者术前血清白细胞介素6 (IL-6)、胃蛋白酶原(PG)Ⅰ、Ⅱ及PG-Ⅰ/Ⅱ比值在患者预后评估中的意义。方法选择2016年1月—2017年1月南通大学附属海安医院收治的101例外科手术治疗的老年胃癌患者为研究对象。收集患者的临床病理资料,检测血清IL-6和PG-Ⅰ/Ⅱ水平。以全因死亡为随访终点,使用Kaplan-Meier曲线明确患者预后与各指标间的关系。结果受试者工作特征曲线提示,IL-6、PG-Ⅰ和PG-Ⅰ/Ⅱ比值在最佳切割值为10.23pg/mL、30.65μg/L和2.44时,可评估患者的预后,而PG-Ⅱ则无法评估患者的预后。与IL-6≤10.23pg/mL组相比,IL-6> 10.23pg/mL组的肿瘤细胞分化更差、TNM分期Ⅲ期比例明显升高。Kaplan-Meier曲线结果表明,IL-6> 10.23pg/mL组的中位生存期显著短于IL-6≤10.23pg/mL组(28个月vs47个月,P<0.001);PG-Ⅰ≤30.65μg/L组的中位生存期显著短于PG-Ⅰ>30.65μg/L组(34个月vs49个月,P=0.008);PG-Ⅰ/Ⅱ≤2.44组的中位生存期显著短于PG-Ⅰ/Ⅱ> 2.44组(29个月vs56个月,P=0.02)。多因素Cox回归分析表明,肿瘤分化程度、TNM分期、IL-6及PG-Ⅰ/Ⅱ比值是影响患者生存率的独立危险因素。结论术前检测IL-6及PG-Ⅰ/Ⅱ比值有助于评估老年胃癌患者的预后。 相似文献
2.
3.
4.
《Molecular therapy》2022,30(8):2856-2867
- Download : Download high-res image (173KB)
- Download : Download full-size image
5.
《Diagnostic Histopathology》2022,28(11):493-500
After decades of relative stagnation lung cancer is emerging as a disease type where rapid progress is being made in diagnosis and therapy, as well as in our understanding of disease biology. Much of this progress is of immediate impact to diagnosticians, and more is likely to affect diagnostic practice in the near future. In this review we seek to briefly summarize several key areas of active research of immediate or probable imminent value to trainee and consultant pulmonary pathologists alike. We cover some major changes in tumour classification, grading, and patient stratification, as well as considering the state of the art in machine-assisted interpretation of lung cancer histology, and the use of genetically modified lung cancer models. 相似文献
6.
目的:探讨姑息性胃切除联合术后化疗评分在腹膜转移的胃癌患者预后评估中的临床意义。方法:回顾性分析2010年1月至2016年12月7年间收治的287例发生腹膜转移的胃癌患者的临床病理资料。通过χ2检验分析评分与患者临床病理因素间的关系。通过Kaplan-Meier法绘制生存曲线,Log-rank检验比较患者生存率的差异;采用Cox比例风险回归模型对患者进行预后分析。结果:与评分中得分为2分和1分的患者相比,得分为0分的患者肿瘤侵润至T4b 期的患者较少[31%(18/58)比50.8%(63/124)、56.2%(59/105),P=0.039]。全组患者的中位生存时间仅为8.7月。对患者进行单因素预后分析结果显示,血清白蛋白浓度(≤40 g/L),腹水,腹膜转移范围较大,肿瘤T分期较晚,评分得分较高的患者预后较差(均P<0.05)。将上述因素纳入Cox多因素分析结果显示:评分[HR(95%CI):1.384(1.165~1.644),P=0.000],血清白蛋白浓度[HR(95%CI):0.759(0.593~0.971),P=0.028],肿瘤T分期[HR(95%CI):1.493(1.216~1.832),P=0.000]是患者预后的独立危险因素。结论:评分对于胃癌伴腹膜转移患者的预后生存评估具有重要的临床意义。 相似文献
7.
目前临床研究已证实腹腔镜胃癌根治术治疗早期胃癌的安全性、可行性和有效性。基于此,第4版日本《胃癌治疗指南》推荐腹腔镜手术治疗临床Ⅰ期远端胃癌。然而,腹腔镜胃癌手术治疗进展期胃癌的有效性和安全性仍存争议。中国腹腔镜胃肠外科研究组(CLASS研究组)发起的CLASS-01研究顺利完成,提供了全球首个局部进展期胃癌腹腔镜手术安全性和疗效的前瞻性多中心证据。胃癌外科的主流方向在从“大切口和扩大化手术切除”逐渐向“微创、精准化手术”转变,以使手术安全性和病人术后生活质量最优化。 相似文献
8.
Ehsan Zarei Elmira Madarshahian Adeleh Nikkhah Soheila Khodakarim 《Journal of tissue viability》2019,28(2):70-74
Background and objective
Pressure ulcer (PU) is one of the important and frequent complications of hospitalization, associated with high treatment costs. The present study was conducted to determine the incidence of PU and its direct treatment costs for patients in intensive care unit (ICU) in Iran.Material and methods
In this retrospective study, medical records of 643 discharged patients from ICU of two selected hospitals were examined. The demographic and clinical data of all patients and data of resources and services usage for patients with PU were extracted through their records. Data analysis was done using logistic regression tests in SPSS 22 software. The cost of PU treatment was calculated for each grade of ulcer.Results
The findings showed that 8.9% of patients developed PU during their stay in ICU. Muscular paralysis (OR?=?5.1), length of stay in ICU (OR?=?4.0), diabetes (OR?=?3.5) age (OR?=?2.9), smoking (OR?=?2.1) and trauma (OR?=?1.4) were the most important risk factors of PU. The average cost of PU treatment varied from USD 12 for grade I PU to USD 66?834 for grade IV PUs. The total treatment costs for all studied patients with PU was estimated at USD 519?991.Conclusion
The cost of PU treatment is significant. Since the preventive measures are more cost-effective than therapeutic measures, therefore, effective preventive interventions are recommended. 相似文献9.
Unconditional Positivity-Preserving and Energy Stable Schemes for a Reduced Poisson-Nernst-Planck System
下载免费PDF全文
![点击此处可从《Communications In Computational Physics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Hailiang Liu & Wumaier Maimaitiyiming 《Communications In Computational Physics》2020,27(5):1505-1529
The Poisson-Nernst-Planck (PNP) system is a widely accepted model for
simulation of ionic channels. In this paper, we design, analyze, and numerically validate a second order unconditional positivity-preserving scheme for solving a reduced
PNP system, which can well approximate the three dimensional ion channel problem.
Positivity of numerical solutions is proven to hold true independent of the size of time
steps and the choice of the Poisson solver. The scheme is easy to implement without
resorting to any iteration method. Several numerical examples further confirm the
positivity-preserving property, and demonstrate the accuracy, efficiency, and robustness of the proposed scheme, as well as the fast approach to steady states. 相似文献
10.
BackgroundEpidemiological studies on peptic ulcer disease (PUD) have shown a recent decrease in hospital admissions in Western countries.ObjectiveThis paper aimed to study the current status and risk factors of PUD in a Nigerian metropolis.MethodsA cross-sectional study of symptomatic patients at upper gastrointestinal (GI) endoscopy diagnosed with PUD from February 2014 to September 2019 at a referral endoscopy facility in Port Harcourt, Niger delta region of Nigeria. The variables studied included demographics, symptoms and duration, blood group, chronic non-steroidal anti-inflammatory (NSAID) use, smoking, endoscopic and histology findings. Statistical analysis was performed using SPSS version 20.ResultsA total of 434 upper GI endoscopies were performed during the study period with thirty-one diagnosis of PUD made. The mean age of gastric ulcer (GU) and duodenal ulcer (DU) cases were 54.4 ± 20.2yrs and 48.1 ± 14.5yrs respectively (p = 0.367). GU to DU ratio was 1.4:1. H. pylori infection, chronic NSAID use and blood group O were seen in 7(22.5%), 8(25.8%) and 18(72.0%) respectively. Major indication in 21(67.7%) cases was gastrointestinal bleeding.ConclusionThere is a low diagnostic rate of PUD (6.7%) with pre-pyloric antral gastric ulcers as most common type and multifactorial aetiology. 相似文献