全文获取类型
收费全文 | 3854篇 |
免费 | 383篇 |
国内免费 | 297篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 101篇 |
妇产科学 | 24篇 |
基础医学 | 507篇 |
口腔科学 | 192篇 |
临床医学 | 195篇 |
内科学 | 1348篇 |
皮肤病学 | 41篇 |
神经病学 | 207篇 |
特种医学 | 15篇 |
外科学 | 212篇 |
综合类 | 213篇 |
现状与发展 | 4篇 |
预防医学 | 896篇 |
眼科学 | 20篇 |
药学 | 250篇 |
中国医学 | 157篇 |
肿瘤学 | 141篇 |
出版年
2024年 | 50篇 |
2023年 | 255篇 |
2022年 | 641篇 |
2021年 | 667篇 |
2020年 | 465篇 |
2019年 | 331篇 |
2018年 | 235篇 |
2017年 | 243篇 |
2016年 | 192篇 |
2015年 | 175篇 |
2014年 | 240篇 |
2013年 | 302篇 |
2012年 | 108篇 |
2011年 | 74篇 |
2010年 | 55篇 |
2009年 | 57篇 |
2008年 | 61篇 |
2007年 | 45篇 |
2006年 | 47篇 |
2005年 | 37篇 |
2004年 | 35篇 |
2003年 | 23篇 |
2002年 | 18篇 |
2001年 | 14篇 |
2000年 | 11篇 |
1999年 | 19篇 |
1998年 | 13篇 |
1997年 | 14篇 |
1996年 | 12篇 |
1995年 | 8篇 |
1994年 | 9篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1968年 | 1篇 |
1907年 | 1篇 |
排序方式: 共有4534条查询结果,搜索用时 15 毫秒
71.
Q. R. Li C. Y. Wang C. Tang Q. He N. Li J. S. Li 《American journal of transplantation》2013,13(4):899-910
It has been known that the gut microbiota plays a central role in shaping normal mucosal immunity, however, little information is available whether the variability of mucosal lymphocytes impacts the commensal flora. Here, we applied a cynomolgus monkey model to characterize the structure and composition of the gut microbiota in response to lymphocyte depletion and to determine their potential association. Molecular profiling of 16S rDNA showed that the intestinal microbiota composition was perturbed after the depletion of mucosal lymphocytes and were recovered following the repopulation. Some specific bacteria from the orders Lactobacillales, Enterobacteriales and Clostridiales, and the genus Prevotella and Faecalibacterium, were primarily responsible for the variations of the gut microbiota after lymphocyte depletion. Interestingly, the species richness of the ileal mucosal microbiota was associated the proportions of TCRαβ+ or TCRγδ+ T cells (p < 0.01). We demonstrate for the first time the feature of intestinal microbiota composition after lymphocyte depletion and provide novel evidence that the perturbation of gut microbiota is associated with lymphocyte depletion. It may contribute to understand the relationship between gut commensal microbiota and mucosal immune system. Study results provide insight into biological activity of alemtuzumab in intestinal barrier in organ transplantation. 相似文献
72.
73.
目的 观察新生儿口腔微生物的早期定植情况 ,确定健康新生儿口腔正常微生物群的组成以及新生儿口腔中的优势细菌。方法 对 2 2名健康新生儿口腔进行棉拭子取样 ,在需氧、兼性厌氧、厌氧条件下培养 ,培养均采用成品培养基和培养盒 ,培养结果作微生物的形态学及生化鉴定。结果 90 .9%的刚出生健康新生儿口腔中无菌 ;4 5 .5 %的新生儿出生第 2天即可检出 Streptococcus salivarius(S.salivarius) ,2 7.3%可检出 Streptococ-cus mitis(S.mitis) ,到出生后第 2 8天这两种菌的检出率分别达 86 .4 %和 81.8% ;Candida albicans(C.albicans)在1月龄新生儿口腔中检出率为 2 2 .7% ;母乳喂养与人工喂养的新生儿口腔正常微生物群之间无明显差异 (P>0 .0 5 )。结论 在早期定植于健康新生儿口腔生态区的正常微生物中 ,S.salivarius和 S.mitis为其优势细菌 ,C.albi-cans为优势真菌。不同喂养方式对新生儿口腔优势菌群的组成和数量无明显影响。 相似文献
74.
Yoshio Suzuki Taisei Miyahara Minami Jinnouchi Yoshiki Miura Hikari Taka Naoko Kaga Akiko Ohara-Takada 《Nutrients》2022,14(9)
We previously reported that healthy adult males who consumed coix seeds for 1 week demonstrated an increased intestinal abundance of Faecalibacterium prausnitzii and altered peripheral lymphocyte subset percentages. However, the mechanism underlining these effects has not been elucidated. Therefore, cytokines and metabolites in plasma obtained in this study are comprehensively analyzed. A total of 56 cytokines and 52 metabolites in the plasma are quantified. Among them, 14 cytokines and 9 metabolites show significant changes in their levels following coix seed consumption. We examine the relationship between these changes and those in peripheral lymphocyte subset percentages and intestinal abundance of F. prausnitzii, which is also considerably altered following coix seed consumption. The galectin-9 concentration considerably decreased after coix seed consumption, and these changes correlate with those in cytotoxic T cells and pan T cells. Therefore, galectin-9 is possibly involved in the changes in peripheral lymphocyte subset percentages induced by coix seed consumption. 相似文献
75.
Manoj Kumar Namrata Pal Poonam Sharma Manoj Kumawat Devojit Kumar Sarma Bilkees Nabi Vinod Verma Rajnarayan R. Tiwari Swasti Shubham Bahram Arjmandi Ravinder Nagpal 《Nutrients》2022,14(9)
Type-2 diabetes mellitus (T2DM) is often linked with hyperglycemia, disturbed lipid profiles, inflammation, and gut dysbiosis. Omega-3 fatty acid supplementation has a vital role in the management of T2DM. As a result, a better understanding of the potential role of omega-3 fatty acids in the development and progression of T2DM by influencing the intestinal microflora will help to improve the therapeutic intervention for T2DM and related complications. Focusing on the molecular mechanisms and signaling pathways induced by omega-3 fatty acids, this paper attempts to comprehensively review and discuss the putative associations between omega-3 fatty acids, gut dysbiosis, and the pathophysiology of T2DM and its related comorbidities. In addition, we contemplate the importance of gut microbiota in T2DM prevention and treatment and ponder the role of omega-3 fatty acids in T2DM by positively modulating gut microbiota, which may lead to discovery of novel targets and therapeutic strategies thereby paving way for further comprehensive, mechanistic, and clinical studies. 相似文献
76.
Ins Reigada Karmen Kapp Claire Maynard David Weinkove Marta Sofía Valero Elisa Langa Leena Hanski Carlota Gmez-Rincn 《Nutrients》2022,14(9)
Guarana (Paullinia cupana) is a widely consumed nutraceutical with various health benefits supported by scientific evidence. However, its indirect health impacts through the gut microbiota have not been studied. Caenorhabditis elegans is a useful model to study both the direct and indirect effects of nutraceuticals, as the intimate association of the worm with the metabolites produced by Escherichia coli is a prototypic simplified model of our gut microbiota. We prepared an ethanoic extract of guarana seeds and assessed its antioxidant capacity in vitro, with a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and in vivo, utilizing C. elegans. Additionally, we studied the impact of this extract on C. elegans lifespan, utilizing both viable and non-viable E. coli, and assessed the impact of guarana on E. coli folate production. The extract showed high antioxidant capacity, and it extended worm lifespan. However, the antioxidant and life-extending effects did not correlate in terms of the extract concentration. The extract-induced life extension was also less significant when utilizing dead E. coli, which may indicate that the effects of guarana on the worms work partly through modifications on E. coli metabolism. Following this observation, guarana was found to decrease E. coli folate production, revealing one possible route for its beneficial effects. 相似文献
77.
目的研究丹参注射液对术后完全肠外营养(TPN)患者肠道功能的影响。方法将24例术后TPN患者随机分为对照组(12例)和中药组(12例),对照组给予常规TPN治疗,中药组在常规TPN治疗同时给予丹参注射液静滴,分别观察两组术后第1天、第3天及第7天的二胺氧化酶(DAO)和循环D-乳酸(D-Lac)的变化。结果对照组与中药组患者术后第3天与术后1 d比较,DAO和D-Lac均升高(P〈0.05),但两组比较差异无统计学意义(P〉0.05);对照组术后第7天较术后第3天DAO和D-Lac显著升高(P〈0.05);而中药组术后第7天较术后第3天明显降低(P〈0.01),且DAO、D-Lac均显著低于对照组(P〈0.01)。结论丹参可以明显改善腹部术后长期TPN患者肠黏膜通透性,提高肠道屏障功能,修复肠道黏膜受损细胞,消除肠功能障碍。 相似文献
78.
目的:探索放大肠镜在重症急性胰腺炎(SAP)早期肠黏膜屏障功能障碍导致的结肠黏膜损伤诊断中的价值。方法:对35例早期SAP病人进行放大肠镜检查,观察结肠黏膜有无损害,并取活检进行病理学光镜和电镜检查,同时对其进行APACHEⅡ评分、胃肠功能评分、胰周组织感染发生率统计。结果:71.4%(25/35)的早期SAP病人在放大肠镜检查中发现有结肠黏膜损伤,包括黏膜水肿、出血、糜烂。77.1%(27/35)的病人活检组织病理检查发现异常,包括黏膜上皮脱落、紧密连接缩短、细胞间分离。放大肠镜发现结肠黏膜损伤的病人其病理检查异常率、APACHEⅡ评分、胃肠功能评分、胰周感染发生率均高于未发现结肠黏膜损伤的病人。结论:对早期SAP病人进行放大肠镜检查,能够评估病人疾病的严重程度,预测病程进展中发生胰周感染的概率。 相似文献
79.
Fenglian Ma Mengying Sun Yinglong Song Arong Wang Shujuan Jiang Fang Qian Guangqing Mu Yanfeng Tuo 《Nutrients》2022,14(9)
In our previous research, Lactiplantibacillus plantarum-12 alleviated inflammation in dextran sodium sulfate (DSS)-induced mice by regulating intestinal microbiota and preventing colon shortening (p < 0.05). The purpose of the present study was to evaluate whether L. plantarum-12 could ameliorate the colon cancer symptoms of azoxymethane (AOM)/DSS-treated C57BL/6 mice. The results showed that L. plantarum-12 alleviated colonic shortening (from 7.43 ± 0.15 to 8.23 ± 0.25) and weight loss (from 25.92 ± 0.21 to 27.75 ± 0.88) in AOM/DSS-treated mice. L. plantarum-12 oral administration down-regulated pro-inflammatory factors TNF-α (from 350.41 ± 15.80 to 247.72 ± 21.91), IL-8 (from 322.19 ± 11.83 to 226.08 ± 22.06), and IL-1β (111.43 ± 8.14 to 56.90 ± 2.70) levels and up-regulated anti-inflammatory factor IL-10 (from 126.08 ± 24.92 to 275.89 ± 21.87) level of AOM/DSS-treated mice. L. plantarum-12 oral administration restored the intestinal microbiota dysbiosis of the AOM/DSS treated mice by up-regulating beneficial Muribaculaceae, Lactobacillaceae, and Bifidobacteriaceae levels and down-regulating pathogenic Proteobacteria, Desulfovibrionaceae, and Erysipelotrichaceae levels. As a result, the fecal metabolites of the AOM/DSS-treated mice were altered, including xanthosine, uridine, 3,4-methylenesebacic acid, 3-hydroxytetradecanedioic acid, 4-hydroxyhexanoylglycine, beta-leucine, and glycitein, by L. plantarum-12 oral administration. Furthermore, L. plantarum-12 oral administration significantly ameliorated the colon injury of the AOM/DSS-treated mice by enhancing colonic tight junction protein level and promoting tumor cells death via down-regulating PCNA (proliferating cell nuclear antigen) and up-regulating pro-apoptotic Bax. (p < 0.05). Taken together, L. plantarum-12 oral administration could ameliorate the colon cancer burden and inflammation of AOM-DSS-treated C57BL/6 mice through regulating the intestinal microbiota, manipulating fecal metabolites, enhancing colon barrier function, and inhibiting NF-κB signaling. These results suggest that L. plantarum-12 might be an excellent probiotic candidate for the prevention of colon cancer. 相似文献
80.
目的 探讨人工生物膜对大鼠肠缺血再灌注所致小肠及肝脏损伤的保护作用。方法 选用健康Wistar大鼠32只,随机分成假手术对照组、缺血灌注组(I/R)、缺血前给药组和再灌注时给药组。夹闭大鼠肠系膜上动脉(SMA)60min造成缺血,再灌2h后分别取出小肠、肝组织制成匀浆,测定超氧化物歧化酶(SOD)、谷胱甘肽过氧化酶(GSH-PX)、丙二醛(MDA)、Ca^2 -Mg^2 -ATPase的含量。结果 缺血前给药组和再灌注时给药组小肠、肝组织MDA含量明显低于缺血再灌注组(P<0.01),SOD、GSH-PX、Ca^2 -Mg^2 -ATPase的含量均明显高于缺血再灌注组(P<0.01),而缺血前给药组和再灌注时给药组各项指标比较无明显差异(P>0.05)。结论 人工生物膜能减少大鼠脂质过氧化,改善ATPase功能,减轻大鼠肠缺血再灌注所致小肠及肝损伤。 相似文献