全文获取类型
收费全文 | 5774篇 |
免费 | 406篇 |
国内免费 | 220篇 |
专业分类
耳鼻咽喉 | 99篇 |
儿科学 | 96篇 |
妇产科学 | 115篇 |
基础医学 | 1041篇 |
口腔科学 | 759篇 |
临床医学 | 430篇 |
内科学 | 543篇 |
皮肤病学 | 233篇 |
神经病学 | 297篇 |
特种医学 | 243篇 |
外国民族医学 | 1篇 |
外科学 | 382篇 |
综合类 | 790篇 |
预防医学 | 217篇 |
眼科学 | 189篇 |
药学 | 414篇 |
中国医学 | 114篇 |
肿瘤学 | 437篇 |
出版年
2023年 | 69篇 |
2022年 | 95篇 |
2021年 | 171篇 |
2020年 | 152篇 |
2019年 | 132篇 |
2018年 | 143篇 |
2017年 | 147篇 |
2016年 | 151篇 |
2015年 | 187篇 |
2014年 | 346篇 |
2013年 | 399篇 |
2012年 | 327篇 |
2011年 | 366篇 |
2010年 | 296篇 |
2009年 | 275篇 |
2008年 | 280篇 |
2007年 | 263篇 |
2006年 | 256篇 |
2005年 | 216篇 |
2004年 | 213篇 |
2003年 | 198篇 |
2002年 | 157篇 |
2001年 | 118篇 |
2000年 | 119篇 |
1999年 | 129篇 |
1998年 | 88篇 |
1997年 | 102篇 |
1996年 | 78篇 |
1995年 | 87篇 |
1994年 | 67篇 |
1993年 | 68篇 |
1992年 | 61篇 |
1991年 | 48篇 |
1990年 | 43篇 |
1989年 | 45篇 |
1988年 | 39篇 |
1987年 | 43篇 |
1986年 | 38篇 |
1985年 | 47篇 |
1984年 | 66篇 |
1983年 | 25篇 |
1982年 | 57篇 |
1981年 | 36篇 |
1980年 | 44篇 |
1979年 | 28篇 |
1978年 | 23篇 |
1977年 | 16篇 |
1976年 | 12篇 |
1975年 | 7篇 |
1973年 | 8篇 |
排序方式: 共有6400条查询结果,搜索用时 62 毫秒
1.
2.
《Clinical breast cancer》2022,22(6):507-514
Breast cancer (BC) is a highly metastatic, pathological cancer that significantly affects women worldwide. The mortality rate of BC is related to its heterogeneity, aggressive phenotype, and metastasis. Recent studies have highlighted that the tumor microenvironment (TME) is critical for the interplay between metastasis mediators in BC. BC stem cells, tumor-derived exosomes, circulatory tumor cells (CTCs), and signaling pathways dynamically remodel the TME and promote metastasis. This review examines the cellular and molecular mechanisms governing the epithelial to mesenchymal transition (EMT) that facilitate metastasis. This review also discusses the role of cancer stem cells (CSCs), tumor-derived exosomes, and CTs in promoting BC metastasis. Furthermore, the review emphasizes major signaling pathways that mediate metastasis in BC. Finally, the interplay among CSCs, exosomes, and CTCs in mediating metastasis have been highlighted. Therefore, understanding the molecular cues that mediate the association of CSCs, exosomes, and CTCs in TME helps to optimize systemic therapy to target metastatic BC. 相似文献
3.
4.
《Vaccine》2021,39(14):1933-1942
The genetic and antigenic drift associated with the high pathogenicity avian influenza (HPAI) viruses of Goose/Guangdong (Gs/GD) lineage and the emergence of vaccine-resistant field viruses underscores the need for a broadly protective H5 influenza A vaccine. Here, we tested experimental vector herpesvirus of turkey (vHVT)-H5 vaccines containing either wild-type clade 2.3.4.4A-derived H5 inserts or computationally optimized broadly reactive antigen (COBRA) inserts with challenge by homologous and genetically divergent H5 HPAI Gs/GD lineage viruses in chickens. Direct assessment of protection was confirmed for all the tested constructs, which provided clinical protection against the homologous and heterologous H5 HPAI Gs/GD challenge viruses and significantly decreased oropharyngeal shedding titers compared to the sham vaccine. The cross reactivity was assessed by hemagglutinin inhibition (HI) and focus reduction assay against a panel of phylogenetically and antigenically diverse H5 strains. The COBRA-derived H5 inserts elicited antibody responses against antigenically diverse strains, while the wild-type-derived H5 vaccines elicited protection mostly against close antigenically related clades 2.3.4.4A and 2.3.4.4D viruses. In conclusion, the HVT vector, a widely used replicating vaccine platform in poultry, with H5 insert provides clinical protection and significant reduction of viral shedding against homologous and heterologous challenge. In addition, the COBRA-derived inserts have the potential to be used against antigenically distinct co-circulating viruses and future drift variants. 相似文献
5.
《Saudi Pharmaceutical Journal》2022,30(6):669-678
BackgroundIschemia reperfusion (I/R) play an imperative role in the expansion of cardiovascular disease. Sinomenine (SM) has been exhibited to possess antioxidant, anticancer, anti-inflammatory, antiviral and anticarcinogenic properties. The aim of the study was scrutinized the cardioprotective effect of SM against I/R injury in rat.MethodsRat were randomly divided into normal control (NC), I/R control and I/R + SM (5, 10 and 20 mg/kg), respectively. Ventricular arrhythmias, body weight and heart weight were estimated. Antioxidant, inflammatory cytokines, inflammatory mediators and plasmin system indicator were accessed.ResultsPre-treated SM group rats exhibited the reduction in the duration and incidence of ventricular fibrillation, ventricular ectopic beat (VEB) and ventricular tachycardia along with suppression of arrhythmia score during the ischemia (30 and 120 min). SM treated rats significantly (P < 0.001) altered the level of antioxidant parameters. SM treatment significantly (P < 0.001) repressed the level of creatine kinase MB (CK-MB), creatine kinase (CK) and troponin I (Tnl). SM treated rats significantly (P < 0.001) repressed the tissue factor (TF), thromboxane B2 (TXB2), plasminogen activator inhibitor 1 (PAI-1) and plasma fibrinogen (Fbg) and inflammatory cytokines and inflammatory mediators.ConclusionOur result clearly indicated that SM plays anti-arrhythmia effect in I/R injury in the rats via alteration of oxidative stress and inflammatory reaction. 相似文献
6.
《Pancreatology》2019,19(6):819-827
BackgroundPeriprocedural intravenous hydration is suggested to decrease the risk of post-ERCP pancreatitis (PEP). However, quality of evidence supporting this suggestion remains poor. Here we hypothesized that aggressive hydration(AH) could be an effective preventive measure.MethodsPubmed, EMBASE, CINAHL, Google Scholar, Clinical Trials. gov, Clinical Key, International Standard Randomized Trial Number registry as well as secondary sources were searched through January 2019 to identify randomized controlled studies comparing AH to standard hydration (SH) for prevention of PEP. Pooled odds ratio (OR) and 95% confidence intervals (CIs) were calculated using the random-effects model. RevMan 5.3 was used for analysis.ResultsA total of 9 RCTs, with 2094 patients, were included in the meta-analysis. AH reduced incidence of PEP by 56% compared to SH (OR = 0.44, CI:0.28–0.69; p = 0.0004). The incidence of post-ERCP hyperamylasemia also decreased with AH compared to SH (OR = 0.51; p = 0.001). Length of stay decreased by 1 day with AH (Mean Difference (MD): −0.89 d; p = 0.00002). There was no significant difference in adverse events related to fluid overload between two groups (OR:1.29; p = 0.81) and post-ERCP abdominal pain (OR:0.35; p = 0.17). Numbers of patient to be treated with AH to prevent one episode of PEP was 17. Final results of the meta-analysis were not affected by alternative effect measures or statistical models of heterogeneity.ConclusionAggressive hydration is associated with a significantly lower incidence of PEP and it appears to be an effective and safe strategy for the prevention of Post ERCP pancreatitis. 相似文献
7.
目的 研究不同照射方式下核黄素-A波紫外线兔巩膜胶原交联术对兔巩膜成纤维细胞生物力学特性的影响。方法 取健康新西兰大白兔24只,随机将兔平均分为A、B两组,每组选取左眼为实验眼,右眼为对照眼。麻醉后暴露左眼鼻上方巩膜。在该处巩膜滴加5-磷酸核黄素5 min后,用波长为370 nm的紫外线灯照射。A组的照射时间为30 min,能量密度为3.0 mW·cm-2;B组的照射时间为9 min,能量密度为10.0 mW·cm-2。照射期间,每2 min滴加1次5-磷酸核黄素溶液,以保持巩膜的湿润。术后60 d,处死实验兔,培养实验眼交联部位及对照眼相应部位的巩膜成纤维细胞,用细胞微管吸吮实验检测巩膜成纤维细胞的杨氏模量、表观黏性。结果 A、B两组实验眼巩膜细胞的杨氏模量、表观黏性均较各自对照眼显著增强,差异均有统计学意义(均为P<0.05);而A、B两组实验眼间、及对照眼间巩膜细胞的杨氏模量、表观黏性差异无统计学意义(均为P>0.05)。以上结果表明,交联术后巩膜细胞的黏弹性发生了明显的变化,黏弹性显著升高。而两种照射方式之间巩膜细胞的黏弹性无显著差异。结论 两种不同的照射方式,均能使巩膜成纤维细胞的生物力学性能发生显著增强,而两种照射方式之间并未见明显的差别。 相似文献
8.
《Vaccine》2019,37(31):4382-4391
Cancer-associated fibroblasts (CAFs), major components of the tumor microenvironment (TME), promote tumor growth and metastasis and inhibit the anti-tumor immune response. We previously constructed a DNA vaccine expressing human FAPα, which is highly expressed by CAFs, to target these cells in the TME, and observed limited anti-tumor effects in the 4T1 breast cancer model. When the treatment time was delayed until tumor nodes formed, the anti-tumor effect of the vaccine completely disappeared. In this study, to improve the safety and efficacy, we constructed a new FAPα-targeted vaccine containing only the extracellular domain of human FAPα with a tissue plasminogen activator signal sequence for enhanced antigen secretion and immunogenicity. The number of CAFs was more effectively reduced by CD8+ T cells induced by the new vaccine. This resulted in decreases in CCL2 and CXCL12 expression, leading to a significant decrease in the ratio of myeloid-derived suppressor cells in the TME. Moreover, when mice were treated after the establishment of tumors, the vaccine could still delay tumor growth. To facilitate the future application of the vaccine in clinical trials, we further optimized the gene codons and reduced the homology between the vaccine and the original sequence, which may be convenient for evaluating the vaccine distribution in the human body. These results indicated that the new FAPα-targeted vaccine expressing an optimized secreted human FAPα induced enhanced anti-tumor activity by reducing the number of FAPα+ CAFs and enhancing the recruitment of effector T cells in the 4T1 tumor model mice. 相似文献
9.
10.