全文获取类型
收费全文 | 22324篇 |
免费 | 1686篇 |
国内免费 | 1074篇 |
专业分类
耳鼻咽喉 | 304篇 |
儿科学 | 211篇 |
妇产科学 | 237篇 |
基础医学 | 2016篇 |
口腔科学 | 685篇 |
临床医学 | 2988篇 |
内科学 | 2254篇 |
皮肤病学 | 156篇 |
神经病学 | 1085篇 |
特种医学 | 540篇 |
外国民族医学 | 6篇 |
外科学 | 1549篇 |
综合类 | 5248篇 |
现状与发展 | 5篇 |
预防医学 | 1926篇 |
眼科学 | 404篇 |
药学 | 2179篇 |
34篇 | |
中国医学 | 2192篇 |
肿瘤学 | 1065篇 |
出版年
2024年 | 44篇 |
2023年 | 352篇 |
2022年 | 952篇 |
2021年 | 1060篇 |
2020年 | 1099篇 |
2019年 | 772篇 |
2018年 | 820篇 |
2017年 | 684篇 |
2016年 | 761篇 |
2015年 | 877篇 |
2014年 | 1635篇 |
2013年 | 1415篇 |
2012年 | 1849篇 |
2011年 | 1958篇 |
2010年 | 1603篇 |
2009年 | 1329篇 |
2008年 | 951篇 |
2007年 | 1382篇 |
2006年 | 1320篇 |
2005年 | 871篇 |
2004年 | 657篇 |
2003年 | 368篇 |
2002年 | 328篇 |
2001年 | 290篇 |
2000年 | 233篇 |
1999年 | 249篇 |
1998年 | 187篇 |
1997年 | 170篇 |
1996年 | 118篇 |
1995年 | 95篇 |
1994年 | 120篇 |
1993年 | 46篇 |
1992年 | 101篇 |
1991年 | 92篇 |
1990年 | 86篇 |
1989年 | 29篇 |
1988年 | 38篇 |
1987年 | 34篇 |
1986年 | 40篇 |
1985年 | 14篇 |
1984年 | 17篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 11篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
目的 对比研究朝鲜淫羊藿酸性多糖酯化还原前后的理化特性,并探讨其改善油酸诱导的肝癌HepG2细胞脂质堆积活性的差异。方法 采用高效凝胶渗透色谱法测定朝鲜淫羊藿酸性多糖(EFPA)的均一性和分子量,高效液相色谱法测定EFPA和酯化还原后朝鲜淫羊藿酸性多糖(EFPA-R)的单糖组成;采用油酸(OA)处理HepG2细胞诱导建立脂质蓄积模型,不同浓度EFPA与EFPA-R(10、30、100、300 μg·mL-1)分别和OA共同作用于细胞24 h,采用CCK-8试剂盒测定细胞存活率,油红O染色观察细胞内脂滴蓄积情况,并采用试剂盒测定细胞内总胆固醇(TC)、甘油三酯(TG)含量。结果 EFPA为成分均一的多糖组分,分子量为125.8 kDa,由甘露糖、葡萄糖、半乳糖、葡萄糖醛酸和阿拉伯糖组成,摩尔比为1.7∶7.4∶1.4∶1.8∶1.0,葡萄糖占比最大,EFPA-R由甘露糖、葡萄糖、半乳糖和阿拉伯糖组成,摩尔比为0.8∶10.6∶2.1∶1.0;在10-300 μg·mL-1范围内,EFPA和EFPA-R对HepG2细胞的抑制作用较弱,作为给药浓度;与空白组相比,模型组细胞中TC、TG含量显著升高(P < 0.01),细胞内红色脂滴显著增多,与模型组相比,EFPA可显著降低细胞中TC、TG含量(P < 0.01),明显减少细胞内红色脂滴(P < 0.05或P < 0.01),EFPA-R干预后细胞则无明显变化。结论 EFPA可明显改善HepG2细胞脂质堆积情况,且呈现剂量依赖性,而半乳糖醛酸(GalA)的存在可能是其抑制HepG2细胞脂质蓄积的关键因素。 相似文献
2.
《HPB : the official journal of the International Hepato Pancreato Biliary Association》2022,24(5):681-690
BackgroundThe American Joint Committee on Cancer (AJCC) made improvements for staging pancreatic neuroendocrine tumors (pNETs) in its 8th Edition; however, multicenter studies were not included.MethodsWe collected multicenter datasets (n = 1,086, between 2004 and 2018) to validate the value of AJCC 8 and other coexisting staging systems through univariate and multivariate analysis for well-differentiated (G1/G2) pNETs.ResultsCompared to other coexisting staging systems, AJCC 7 only included 12 (1.1%) patients with stage III tumors. Patients with European Neuroendocrine Tumor Society (ENETS) stage IIB disease had a higher risk of death than patients with stage IIIA (hazard ratio [HR]: 4.376 vs. 4.322). For the modified ENETS staging system, patients with stage IIB disease had a higher risk of death than patients with stage III (HR: 6.078 vs. 5.341). According to AJCC 8, the proportions of patients with stage I, II, III, and IV were 25.7%, 40.3%, 23.6%, and 10.4%, respectively. As the stage advanced, the median survival time decreased (NA, 144.7, 100.8, 72.0 months, respectively), and the risk of death increased (HR: II = 3.145, III = 5.925, and IV = 8.762).ConclusionThese findings suggest that AJCC 8 had a more reasonable proportional distribution and the risk of death was better correlated with disease stage. 相似文献
3.
Toxicity resulting from off-target effects, beyond acetylcholine esterase inhibition, for the commonly used organophosphate (OP) insecticides chlorpyrifos (CPS) and malathion (MA) was investigated using Saccharomyces cerevisiae and Caenorhabditis elegans model systems. Mitochondrial damage and dysfunction were observed in yeast following exposure to CPS and MA, suggesting this organelle is a major target. In the C. elegans model, the mitochondrial unfolded protein response pathway showed the most robust induction from CPS and MA treatment among stress responses examined. GABAergic neurodegeneration was observed with CPS and MA exposure. Impaired movement observed in C. elegans exposed to CPS and MA may be the result of motor neuron damage. Our analysis suggests that stress from CPS and MA results in mitochondrial dysfunction, with GABAergic neurons sensitized to these effects. These findings may aid in the understanding of toxicity from CPS and MA from high concentration exposure leading to insecticide poisoning. 相似文献
4.
We report a Chinese family with members affected by epidermolytic ichthyosis (EI), caused by KRT gene mutations. The proband was a 14‐year‐old boy who had simultaneous appearance of nephroblastoma and epidermolytic ichthyosis (EI). Both the patient and his mother exhibited the specific clinical and pathological manifestations of EI. We analysed all exons and flanking sequences of the KRT1 and KRT10 genes using PCR, and found that the proband and his mother had a G>C transition at nucleotide position 1432 in exon 7 of KRT1, resulting in an amino acid substitution of glutamate (GAA) to glutamine (CAA) at codon 478 (E478Q). The KRT10 gene had no mutations. 相似文献
5.
目的探讨分诊安全管理结合风险管理提高急诊科护理质量评分的作用。方法该院于2018年6月起加强对急诊科的分诊安全管理结合风险管理,以于2017年6月—2019年6月在该院急诊科就诊的患者为研究对象,评价管理策略实施前后护理风险发生率、护理质量评分以及患者满意度等评价指标变化情况。结果实施后基础护理、实践操作、消毒隔离、急救药品、护理文件方面的护理质量评分均较实施前显著提高(P<0.05);实施后护理差错、护理缺陷、护理投诉的发生率分别为0.26%、0.58%、0.19%,均较实施前显著降低(P<0.05);实施后护理总满意率为94.92%,较实施前显著提高(P<0.05)。结论分诊安全管理结合风险管理有效提高了急诊科护理质量,提升了患者满意度,减少了护理风险事件的发生。 相似文献
6.
7.
Zheng Xingming Ding Yanling Zhao Xiaowei Bai Yu Li Xiaofeng Zhao Kai 《Remote sensing letters.》2019,10(6):563-572
Vegetation water content (VWC) is the key input parameter for a soil moisture retrieval algorithm based on microwave remote sensing, and VWC uncertainty can limit the estimated accuracy of soil moisture. There has been little research on VWC algorithm development and validation in China, and the uncertainty of the VWC estimation method has not been well evaluated. Therefore, the aim of this study is to evaluate the uncertainty of the VWC estimation method used in the SMAP (Soil Moisture Active Passive) algorithm on three spatial scales (the point-scale, 30 m scale, and 1 km scale) for maize in northeast China. Results from three ground experimental datasets showed that the SMAP VWC estimation method was strongly biased with an average overestimation of 1.16 kg m?2,1.04 kg m?2, and 1.13 kg m?2 for the point-scale, 30 m scale, and 1 km scale respectively, and maximum bias occurred in the mid-stage of maize. Also, a new power relationship between NDVI (Normalized Difference Vegetation Index) and VWC was proposed for the 30 m scale based on Sentinel 2 NDVI and field VWC values from 2017 experiment, with respective R2 (coefficient of determination) and Root Mean Squared Error (RMSE) values of 0.80 and 0.67 kg m?2. The results confirmed that this power relationship was still suitable for VWC estimation at the 1 km scale, and it has smaller bias than the original SMAP VWC method. Future work will be carried out to evaluate the applicability of this VWC estimation method over a lager region. It is expected that it can improve the accuracy of soil moisture by providing high precision VWC input parameters. 相似文献
8.
9.
10.
目的分析护士分层级管理的实施对急性肝炎患者护理满意度的影响。方法该院自2018年3月起实施护士分层级管理,以该院10名肝病科护理人员为研究对象,其中2017年3月—2018年2月实施前(对照组)及2018年3月—2019年2月实施后(研究组)的管理效果。结果与对照组比较,研究组患者的病房管理、患者护理、文书书写、基础护理、入院宣教方面的护理质量评分均明显升高(P<0.05);与对照组82.29%的护理总满意率比较,研究组护理总满意率显著升高,达到了97.92%(P<0.05);与对照组工作自我满意度比较,研究组患者的自我价值体现等方面的工作自我满意度评分均明显升高(P<0.05)。结论护士分层级管理策略的实施,有效提高了急性肝炎患者护理满意度,提升了科室护理质量。 相似文献