全文获取类型
收费全文 | 2918篇 |
免费 | 234篇 |
国内免费 | 58篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 150篇 |
妇产科学 | 20篇 |
基础医学 | 250篇 |
口腔科学 | 22篇 |
临床医学 | 182篇 |
内科学 | 641篇 |
皮肤病学 | 39篇 |
神经病学 | 143篇 |
特种医学 | 45篇 |
外国民族医学 | 1篇 |
外科学 | 96篇 |
综合类 | 420篇 |
预防医学 | 489篇 |
眼科学 | 38篇 |
药学 | 395篇 |
1篇 | |
中国医学 | 179篇 |
肿瘤学 | 90篇 |
出版年
2024年 | 5篇 |
2023年 | 46篇 |
2022年 | 103篇 |
2021年 | 118篇 |
2020年 | 117篇 |
2019年 | 227篇 |
2018年 | 232篇 |
2017年 | 155篇 |
2016年 | 147篇 |
2015年 | 78篇 |
2014年 | 227篇 |
2013年 | 244篇 |
2012年 | 159篇 |
2011年 | 230篇 |
2010年 | 184篇 |
2009年 | 141篇 |
2008年 | 140篇 |
2007年 | 125篇 |
2006年 | 95篇 |
2005年 | 81篇 |
2004年 | 73篇 |
2003年 | 53篇 |
2002年 | 44篇 |
2001年 | 42篇 |
2000年 | 22篇 |
1999年 | 22篇 |
1998年 | 18篇 |
1997年 | 20篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 6篇 |
1986年 | 1篇 |
1985年 | 7篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有3210条查询结果,搜索用时 31 毫秒
41.
42.
43.
目的 调查芜湖市主城区大气 PM2.5中多环芳烃(PAHs)污染特征及其人群健康风险。方法 2020年6月至2021年5月,每月10至16日采集芜湖市主城区大气PM2.5样品,检测和分析其中16种优先控制PAHs浓度及组成特征,并利用特征比值法和物质结构判断PM2.5中PAHs来源,采用US EPA健康风险模型评估其人群健康风险。结果 大气PM2.5浓度均值为49.2μg/m3,范围为7~151μg/m3;16种PAHs均有不同程度检出,总浓度均值为6.85ng/m3,范围为0.13~31.62ng/m3;PM2.5与16种PAHs各月份日均浓度变化存在相关性(R=0.867,P<0.001);16种PAHs季节变化为冬季>秋季>春季>夏季,构成均以4~6 环为主;大气PM2.5中PAHs主要来源为机动车排放和燃煤。PM2.5中16种PAHs的总致癌风险值(Risk)为2.20×10-7,低于1×10-6,致癌风险可忽略;非致癌风险危害商值(HQ)为0.49,小于1,非致癌健康风险低。结论 芜湖市主城区大气PM2.5中PAHs污染较轻,无明显健康风险。 相似文献
44.
The susceptibility and severity of periodontal diseases is made more severe by diabetes, with the impact on the disease process inversely proportional to the level of glycemic control. Although type 1 diabetes mellitus and type 2 diabetes mellitus have different etiologies, and their impact on bone is not identical, they share many of the same complications. Studies in animals and humans agree that both forms of diabetes increase inflammatory events in periodontal tissue, impair new bone formation, and increase expression of RANKL in response to bacterial challenge. High levels of glucose, reactive oxygen species, and advanced glycation end-products are found in the periodontium of diabetic individuals and lead to increased activation of nuclear factor-kappa B and expression of inflammatory cytokines such as tumor necrosis factor and interleukin-1. Studies in animals, moreover, suggest that there are multiple cell types in periodontal tissues that are affected by diabetes, including leukocytes, vascular cells, mesenchymal stem cells, periodontal ligament fibroblasts, osteoblasts, and osteocytes. The etiology of periodontal disease involves the host response to bacterial challenge that is affected by diabetes, which increases the expression of RANKL and reduces coupled bone formation. In addition, the inflammatory response also modifies the oral microbiota to render it more pathogenic, as demonstrated by increased inflammation and bone loss in animals where bacteria are transferred from diabetic donors to germ-free hosts compared with transfer from normoglycemic donors. This approach has the advantage of not relying upon limited knowledge of the specific bacterial taxa to determine pathogenicity, and examines the overall impact of the microbiota rather than the presumed pathogenicity of a few bacterial groups. Thus, animal studies have provided new insights into pathogenic mechanisms that identify cause-and-effect relationships that are difficult to perform in human studies. 相似文献
45.
46.
Symielle A. Gaston Nicolle S. Tulve 《International journal of hygiene and environmental health》2019,222(2):195-204
Objective
There is limited research on the association between phthalates and metabolic syndrome (MetS). Among adolescents, phthalate exposure, which can occur from multiple sources, has been linked to several risk factors for MetS. The objective was to investigate the association between urinary phthalate metabolite concentrations (i.e., mono-ethyl phthalate (MEP), mono-n-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP), mono-benzyl phthalate (MBzP), mono-(3-carboxylpropyl) phthalate (MCPP), and di(2-ethylhexyl phthalate (DEHP)) and MetS in adolescents aged 12–19 years using the National Health and Nutrition Examination Survey (NHANES) data (2003–2014). A secondary aim was to assess if observed associations varied by a measure of socioeconomic status, economic adversity, which was defined using parental income and educational attainment as well as household food security.Methods
We used NHANES data which included physical examination, laboratory urinalysis and fasting blood profiles, and self-reported health characteristics and demographics. Physical examination and laboratory data were used to obtain values of MetS components and urinary phthalate metabolites. We created age-, sex-, and survey year-specific tertiles of creatinine-corrected urinary phthalate metabolites. Analysis was performed using appropriate weighting procedures that accounted for NHANES' complex sampling design. After univariate and bivariate analyses, we performed adjusted logistic regressions to test for associations between individual phthalate metabolites and MetS as well as MetS components and number of MetS components, separately, using the lowest tertile as the reference category. A cross-product term (phthalate metabolite*economic adversity) was subsequently added to adjusted models.Results
Among 918 participants (mean age 16 years, 45% female, 18% with economic adversity), the prevalence of MetS was 5.3%. Prior to adjustment, adolescents with MetS had marginally higher concentrations of phthalate metabolites than adolescents without MetS. There was a suggestive positive association between intermediate concentrations of MnBP and odds of MetS after adjustment (T2: Odds Ratio (OR)?=?2.66 (95% confidence interval: 0.98–7.24); T3: OR?=?2.11 (0.71–6.27)). Males with higher MnBP concentrations had higher odds of dyslipidemia; however, associations were mostly non-significant for females. Relationships between MiBP concentrations and odds of MetS varied by sex. Males with higher concentrations of MnBP and MiBP had greater odds of having a higher number of MetS components. Relationships between phthalate metabolites and MetS did not vary by economic adversity.Conclusion
There was a suggestive positive association between MnBP and MetS among adolescents. Associations between phthalate metabolites and MetS as well as MetS components may vary by sex, but may not vary by economic adversity. Further research of the relationships between phthalate exposures, MetS, and potential interactions with socioeconomic factors is warranted. 相似文献47.
Yiping Li Siqi He Chuanyin Li Keyu Shen Man Yang Wenyu Tao Ying Yang Li Shi Yufeng Yao 《International journal of medical sciences》2021,18(2):356
Background: Type 2 diabetes mellitus (T2DM) is a complex chronic metabolic disorder triggered by insulin resistance in peripheral tissues. Evidence has shown that lipid metabolism and related genetic factors lead to insulin resistance. Hence, it is meaningful to investigate the association between single-nucleotide polymorphisms (SNPs) in lipid metabolism-related genes and T2DM.Methods: A total of 1,194 subjects with T2DM and 1,274 Non-diabetic subjects (NDM) were enrolled. Five SNPs in three genes (rs864745 in JAZF1, rs35767 in IGF1, and rs4376068, rs4402960, and rs6769511 in IGF2BP2) that contribute to insulin resistance involving lipid metabolism were genotyped using the MassArray method in a Chinese population.Results: The allele and genotypes of rs6769511 in IGF2BP2 were associated with T2DM (P=0.009 and P=0.002, respectively). In inheritance model analysis, compared with the T/T-C/T genotype, the C/C genotype of rs6769511 in IGF2BP2 was a risk factor for the development of T2DM (P<0.001, odds ratio [OR] =1.76; 95% confidence interval [CI]: 1.29-2.42). Haplotype analysis revealed associations of the rs4376068-rs4402960-rs6769511 haplotypes in IGF2BP2 with the development of T2DM (P=0.015). Additionally, rs4376068C-rs4402960T-rs6769511C was a risk haplotype for T2DM (OR=1.179; 95% CI: 1.033-1.346).Conclusion: The rs6769511 in IGF2BP2 was associated with T2DM susceptibility, and the rs4376068-rs4402960-rs6769511 haplotypes in IGF2BP2 was associated with the development of T2DM in a Chinese population. 相似文献
48.
49.
Manan Pareek Philip R. Schauer Lee M. Kaplan Lawrence A. Leiter Francesco Rubino Deepak L. Bhatt 《Journal of the American College of Cardiology》2018,71(6):670-687
The alarming rise in the worldwide prevalence of obesity is paralleled by an increasing burden of type 2 diabetes mellitus. Metabolic surgery is the most effective means of obtaining substantial and durable weight loss in individuals with obesity. Randomized trials have recently shown the superiority of surgery over medical treatment alone in achieving improved glycemic control, as well as a reduction in cardiovascular risk factors. The mechanisms seem to extend beyond the magnitude of weight loss alone and include improvements in incretin profiles, insulin secretion, and insulin sensitivity. Moreover, observational data suggest that the reduction in cardiovascular risk factors translates to better patient outcomes. This review describes commonly used metabolic surgical procedures and their current indications and summarizes the evidence related to weight loss and glycemic outcomes. It further examines their potential effects on cardiovascular outcomes and mortality and discusses future perspectives. 相似文献
50.
《Vaccine》2017,35(37):4966-4973
Porcine reproductive and respiratory syndrome virus (PRRSV) causes major economic losses in the swine industry worldwide. Vaccination is the most effective method to control the disease. In a previous study, a chimeric PRRSV named as K418 which had a genome composed of ORF 1 from the FL12 strain and ORF 2-7 from the Korean representative LMY strain was created. We constructed K418DM, K418 with deglycosylated glycoprotein 5 (GP5), to improve its humoral immunity. In the follow-up on in vivo and in vitro virological and serological tests, no back mutation in amino acids of GP5 associated with deglycosylation was shown after 9 passages on MARC-145 cells, whereas only one case of back mutation was detected after single passage in pig. In serological study, K418DM induced higher serum neutralization (SN) antibody and more limited viremia compared with those of K418 virus. In clinical trial and economic analysis, the K418DM elicited SN antibody titers and PRRSV-specific IgG over protection limit. From the economic viewpoint, there was statistically significant reduction in percentage of weak pigs. These results indicated that vaccination with the K418DM may provide enhanced protection for pigs in PRRS endemic situation and increase growth performance in commercial pig farms. 相似文献