全文获取类型
收费全文 | 33781篇 |
免费 | 2456篇 |
国内免费 | 1387篇 |
专业分类
耳鼻咽喉 | 148篇 |
儿科学 | 374篇 |
妇产科学 | 389篇 |
基础医学 | 6787篇 |
口腔科学 | 539篇 |
临床医学 | 2672篇 |
内科学 | 5489篇 |
皮肤病学 | 533篇 |
神经病学 | 3156篇 |
特种医学 | 703篇 |
外国民族医学 | 12篇 |
外科学 | 2939篇 |
综合类 | 4690篇 |
现状与发展 | 12篇 |
预防医学 | 1493篇 |
眼科学 | 457篇 |
药学 | 3101篇 |
8篇 | |
中国医学 | 694篇 |
肿瘤学 | 3428篇 |
出版年
2024年 | 23篇 |
2023年 | 407篇 |
2022年 | 538篇 |
2021年 | 1010篇 |
2020年 | 922篇 |
2019年 | 905篇 |
2018年 | 913篇 |
2017年 | 889篇 |
2016年 | 930篇 |
2015年 | 1081篇 |
2014年 | 1745篇 |
2013年 | 1979篇 |
2012年 | 1674篇 |
2011年 | 1978篇 |
2010年 | 1601篇 |
2009年 | 1665篇 |
2008年 | 1751篇 |
2007年 | 1797篇 |
2006年 | 1627篇 |
2005年 | 1568篇 |
2004年 | 1341篇 |
2003年 | 1180篇 |
2002年 | 1134篇 |
2001年 | 996篇 |
2000年 | 838篇 |
1999年 | 764篇 |
1998年 | 646篇 |
1997年 | 582篇 |
1996年 | 520篇 |
1995年 | 508篇 |
1994年 | 490篇 |
1993年 | 456篇 |
1992年 | 384篇 |
1991年 | 325篇 |
1990年 | 346篇 |
1989年 | 246篇 |
1988年 | 224篇 |
1987年 | 178篇 |
1986年 | 188篇 |
1985年 | 292篇 |
1984年 | 223篇 |
1983年 | 157篇 |
1982年 | 142篇 |
1981年 | 134篇 |
1980年 | 100篇 |
1979年 | 78篇 |
1978年 | 47篇 |
1977年 | 37篇 |
1976年 | 38篇 |
1974年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
11.
《Vaccine》2022,40(33):4889-4896
BackgroundDuring the COVID-19 pandemic, the number of hepatitis B virus (HBV) vaccinations among men who have sex with men (MSM) has been considerably lower than before the pandemic. Moreover, less frequent HBV testing and a reduction in numbers of sex partners have been reported. We assessed the impact of these COVID-19-related changes on HBV transmission among MSM in the Netherlands.MethodsWe estimated the changes in sexual activity, HBV testing, and HBV vaccination among MSM during the pandemic from Dutch data. We used a deterministic compartmental model and investigated scenarios with small or large declines in sexual activity, testing, and vaccination for the current phase of the pandemic (without available data). We examined the increase in HBV vaccinations needed to prevent further increase in HBV incidence.ResultsWith a decrease in numbers of sex partners of 15–25% during the first lockdown and 5% during the second lockdown, we found a decline of 6.6% in HBV incidence in 2020, despite a >70% reduction in HBV testing and vaccination during the first lockdown. With numbers of sex partners rebounding close to pre-pandemic level in 2021, and a reduction of 15% in testing and 30% in vaccination in 2021, we found an increase of 1.4% in incidence in 2021 and 3.1% in 2026. With these changes, an increase of ≥60% in HBV vaccinations in 2022 would be needed to bring the HBV incidence in 2023 back to the level that it would have had if the COVID-19-related changes had not occurred.ConclusionsDespite reductions in sexual activity during the COVID-19 pandemic, the decrease in HBV vaccinations may result in a small increase in HBV incidence after 2021, which may persist for years. It is important to restore the vaccination level and limit further increase in HBV transmission among MSM. 相似文献
12.
《Drug discovery today》2022,27(5):1367-1380
The tremendous advances in genomics, recombinant DNA technology, bioengineering and nanotechnology, in conjunction with the development of high-end computations, have been instrumental in the process of rational design of peptide-based vaccines. The use of peptide vaccines was limited owing to their inherent instability when systemically administered; however, advanced formulation techniques have been developed for their systemic delivery, thereby overcoming their degradation, clearance, cellular uptake and off-target effects. With the rise of sophisticated immunological predictors and experimental techniques, several methodological advances have occurred in this field. This review examines contemporary methods to identify and optimize epitopes, engineer their immunogenic properties and develop their safe and efficient delivery into the host. 相似文献
13.
14.
Defining con-founders that affect the reliability of diagnostic tests for coronavirus disease 2019 is vital to breaking the chain of infection. The elderly population is a higher risk group for the emerging virus. However, gender seems to exert a critical role in modifying the infection risk among women owing to hormonal changes. The menopause transition is an exceptional period for older women where the protective and immunomodulatory effects of the estrogen hormone are lost. Accordingly, attention should be given to postmenopausal women since they will have an increased risk compared to their pre-menopausal peers. 相似文献
15.
16.
17.
18.
《Human immunology》2022,83(12):803-807
We examined the correlation between class I HLA evolutionary divergence (HED), a surrogate for the capacity to present different peptides, and the outcomes of 234 adult inpatients with confirmed SARS-CoV-2 infection. Genomic DNA was extracted from peripheral blood and genotyped by next-generation sequencing (NGS). HED scores for HLA class I (HLA-A, -B, and -C) genotypes were calculated using Grantham’s distance. Higher HED scores for HLA-B, but not HLA-A or -C, are significantly associated with a decreased probability of poor outcomes including ICU admission, mechanical ventilation, and death (OR = 0.93; P = 0.04) in the univariate analysis. In the multivariate analysis, increased HLA-B HED score, younger age, and no comorbidity were independently associated with favorable outcomes (P = 0.02, P = 0.01, and P = 0.05, respectively). This finding is consistent with the notion that broader peptide repertoires presented by class I HLA may be beneficial in infection control. 相似文献
19.
《HPB : the official journal of the International Hepato Pancreato Biliary Association》2022,24(10):1780-1788
BackgroundWe assessed whether or not covalently closed circular DNA (cccDNA) levels in the background liver influence the recurrence of hepatocellular carcinoma (HCC) in patients with resolved hepatitis B virus (HBV) infection.MethodsAmong 425 patients who underwent initial hepatectomy for HCC between 2010 and 2018, a retrospective review was performed in 44 with resolved HBV infection. The clinicopathologic characteristics were analyzed for correlation with tumor recurrence. The HBV cccDNA levels were tested via a droplet digital polymerase chain reaction assay.ResultsHBV cccDNA was detected in 27 of 44 patients (61%), and the median level was 1.0 copies/1000 ng (range, 0-931.3 copies/1000 ng). Anti-HBc ≥8.9 S/CO was associated with cccDNA detection (odds ratio, 11.08; 95% confidence interval [95% CI], 2.48-49.46; P = 0.002). Twenty-eight patients (64%) developed HCC recurrence after hepatectomy. The overall 3- and 5-year recurrence-free survival rates were 45.7% and 34.3%, respectively.19 HBV cccDNA levels was not significantly associated with HCC recurrence, while the presence of multiple tumors was an independent risk fact or (hazard ratio, 6.53; 95% CI, 2.48-17.19; P < 0.001.ConclusionHBV cccDNA levels did not influence HCC recurrence after hepatectomy. Anti-HBc levels may be used as a surrogate marker for cccDNA. 相似文献
20.
《Pancreatology》2022,22(2):270-276
Backgroundand purpose: Zinc is an essential element for human health and plays an important role in metabolic, immunological and other biological processes. The present study was conducted to investigate the association between zinc deficiency (ZD) and the perioperative clinical course in patients with pancreatic ductal adenocarcinoma (PDAC).MethodsOf 216 patients with PDAC who underwent elective pancreatectomy between 2013 and 2017 at our institution, 206 patients with sufficient clinical data were retrospectively reviewed. The perioperative variables were compared and the risk factors associated with infectious complications were identified.ResultsZD was preoperatively present in 36 (17.5%) of 206 patients with PDAC. In the patients of the ZD group, a higher proportion of males, higher preoperative modified Glasgow prognostic scores, a higher neutrophil-to-lymphocyte ratio, and a higher occurrence of postoperative infectious complications after pancreatectomy were observed, compared to the non-ZD group. By a univariate analysis, three risk factors were significantly associated with infectious complications after pancreatectomy: ZD (vs non-ZD: p = 0.002), serum albumin <3.5 g/dl (vs ≥ 3.5 g/dl: p = 0.005), and the procedure of pancreaticoduodenectomy (vs others: p = 0.013). By multivariate logistic regression analysis, the occurrence of infectious complications was significantly associated with ZD (OR 3.430, 95%CI 1.570 to 7.490, p = 0.002) and the procedure of pancreaticoduodenectomy (OR 2.030, 95%CI 1.090 to 3.770, p = 0.025).ConclusionsThe current study newly demonstrated that ZD could serve as a preoperative predictor of infectious complications after pancreatectomies in the patients with PDAC. 相似文献