全文获取类型
收费全文 | 51146篇 |
免费 | 2678篇 |
国内免费 | 423篇 |
专业分类
耳鼻咽喉 | 542篇 |
儿科学 | 961篇 |
妇产科学 | 1433篇 |
基础医学 | 6221篇 |
口腔科学 | 1874篇 |
临床医学 | 3901篇 |
内科学 | 14180篇 |
皮肤病学 | 1035篇 |
神经病学 | 4386篇 |
特种医学 | 1414篇 |
外科学 | 7722篇 |
综合类 | 341篇 |
一般理论 | 10篇 |
预防医学 | 2882篇 |
眼科学 | 792篇 |
药学 | 2869篇 |
中国医学 | 197篇 |
肿瘤学 | 3487篇 |
出版年
2023年 | 337篇 |
2022年 | 671篇 |
2021年 | 1653篇 |
2020年 | 881篇 |
2019年 | 1285篇 |
2018年 | 1734篇 |
2017年 | 1157篇 |
2016年 | 1272篇 |
2015年 | 1472篇 |
2014年 | 1988篇 |
2013年 | 2614篇 |
2012年 | 4041篇 |
2011年 | 4000篇 |
2010年 | 2286篇 |
2009年 | 2006篇 |
2008年 | 3407篇 |
2007年 | 3544篇 |
2006年 | 3298篇 |
2005年 | 3264篇 |
2004年 | 2962篇 |
2003年 | 2709篇 |
2002年 | 2400篇 |
2001年 | 443篇 |
2000年 | 362篇 |
1999年 | 437篇 |
1998年 | 439篇 |
1997年 | 383篇 |
1996年 | 329篇 |
1995年 | 314篇 |
1994年 | 253篇 |
1993年 | 204篇 |
1992年 | 206篇 |
1991年 | 155篇 |
1990年 | 149篇 |
1989年 | 124篇 |
1988年 | 94篇 |
1987年 | 79篇 |
1986年 | 104篇 |
1985年 | 100篇 |
1984年 | 96篇 |
1983年 | 76篇 |
1982年 | 107篇 |
1981年 | 74篇 |
1980年 | 77篇 |
1979年 | 55篇 |
1978年 | 63篇 |
1977年 | 44篇 |
1976年 | 42篇 |
1974年 | 34篇 |
1973年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
981.
982.
Antonio Piralla Ana Moreno Maria Ester Orlandi Elena Percivalle Chiara Chiapponi Fausto Vezzoli Fausto Baldanti the Influenza Surveillance Study Group 《Emerging infectious diseases》2015,21(7):1189-1191
Because swine influenza virus infection is seldom diagnosed in humans, its frequency might be underestimated. We report a immunocompromised hematologic patient with swine influenza A(H3N2) virus in 2014 in Italy. Local pigs were the source of this human infection. 相似文献
983.
984.
Brianna Lindsay Joe Oundo M. Anowar Hossain Martin Antonio Boubou Tamboura Alan W. Walker Joseph N. Paulson Julian Parkhill Richard Omore Abu S.G. Faruque Suman Kumar Das Usman N. Ikumapayi Mitchell Adeyemi Doh Sanogo Debasish Saha Samba Sow Tamer H. Farag Dilruba Nasrin Shan Li Sandra Panchalingam Myron M. Levine Karen Kotloff Laurence S. Magder Laura Hungerford Halvor Sommerfelt Mihai Pop James P. Nataro O. Colin Stine 《Emerging infectious diseases》2015,21(2):242-250
Pathogens in the gastrointestinal tract exist within a vast population of microbes. We examined associations between pathogens and composition of gut microbiota as they relate to Shigella spp./enteroinvasive Escherichia coli infection. We analyzed 3,035 stool specimens (1,735 nondiarrheal and 1,300 moderate-to-severe diarrheal) from the Global Enteric Multicenter Study for 9 enteropathogens. Diarrheal specimens had a higher number of enteropathogens (diarrheal mean 1.4, nondiarrheal mean 0.95; p<0.0001). Rotavirus showed a negative association with Shigella spp. in cases of diarrhea (odds ratio 0.31, 95% CI 0.17–0.55) and had a large combined effect on moderate-to-severe diarrhea (odds ratio 29, 95% CI 3.8–220). In 4 Lactobacillus taxa identified by 16S rRNA gene sequencing, the association between pathogen and disease was decreased, which is consistent with the possibility that Lactobacillus spp. are protective against Shigella spp.–induced diarrhea. Bacterial diversity of gut microbiota was associated with diarrhea status, not high levels of the Shigella spp. ipaH gene. 相似文献
985.
Arianna Aprile Giovanna Palermo Antonio De Luca Roberta Pinalli Enrico Dalcanale Pasquale Pagliusi 《RSC advances》2018,8(29):16314
Reliable chemical sensors with high selectivity and sensitivity toward specific target molecules require rational synthesis of receptors, in-depth characterization of their complexation abilities and highly efficient transduction of the molecular recognition event. Here we report a steady-state and time-resolved fluorescence investigation of EtQxBox, a fluorescent conformationally blocked quinoxaline-based cavitand, aimed at assessing its selectivity toward aromatic versus non-aromatic analytes in solution. Fluorescence quenching of the EtQxBox in acetone is observed at increasing concentration of both aromatic (i.e. benzonitrile) and aliphatic (i.e. acetonitrile) compounds. The combination with fluorescence lifetime measurements permits to discriminate the predominantly static quenching of the aromatic analyte, due to non-fluorescent host–guest complex formation, from the mostly dynamic quenching of the non-aromatic compound, resulting from aspecific diffusive collisions between the fluorophore and the quencher. The equilibrium association constants for both the complexes have been estimated using Stern–Volmer model.We investigate the role of combined static and dynamic quenching in fluorescence transduction of benzonitrile and acetonitrile complexation by a rigid quinoxaline-based cavitand. 相似文献
986.
Ji-Hyeon Park R. Nandi Jae-Kwan Sim Dae-Young Um San Kang Jin-Soo Kim Cheul-Ro Lee 《RSC advances》2018,8(37):20585
III-Nitride nanowires are currently considered as next generation photovoltaic materials due to their excellent physical properties together with reduced dislocation densities, increased surface area and thus enhanced light absorption and direct path for carrier transport. Here, we investigate the photovoltaic characteristics of a solar cell fabricated from a novel hybrid nanostructure comprising uniaxial and coaxial InGaN/GaN multi-quantum wells (MQWs) along with an InGaN nano-cap layer. Various characterization methods were employed to study the optical and structural properties of the hybrid nanostructure. Transmission electron microscopy images revealed the hybrid nanostructure consists of distinct uniaxial and coaxial InGaN/GaN MQWs along with the InGaN nano-cap layer. The InGaN/GaN MQW architectures have a significant effect on the performance of the photovoltaic device. The solar cell fabricated with the hybrid nanostructure exhibits superior photovoltaic performance compared to the uniaxial as well as the coaxial InGaN/GaN nanowire MQW structures. The improved photovoltaic characteristic is primarily attributed to the considerably larger InGaN active area grown in the hybrid nanostructure. A conversion efficiency of 1.16% along with a fill factor of 70% was obtained for the device fabricated with the hybrid nanostructure. This study provides an experimental demonstration of the improvement of III-nitride nanowire based solar cells incorporating uniaxial and coaxial InGaN/GaN MQWs.Solar cells fabricated with hybrid nanowires comprising InGaN/GaN uniaxial and coaxial multi-quantum wells with an InGaN nano-cap layer. 相似文献
987.
目的分析北京某城区2011—2013年感染性腹泻患者致病菌分布及脉冲场凝胶电泳(PFGE)图谱特征,为感染溯源提供依据。方法收集2011年1月—2013年12月该区域肠道门诊感染性腹泻患者粪便标本1 179份,对其培养分离的致病菌进行血清分型及PFGE分析。结果 1 179份标本,共培养肠道病原菌330株,其中检出居前4位的肠道致病菌依次为志贺菌属93株(28.18%)、沙门菌属69株(20.91%)、副溶血性弧菌44株(13.33%)及致泻性大肠埃希菌11株(3.33%)。18株宋内志贺菌PFGE分为8个型别,聚类相似度接近88%;69株沙门菌属细菌分为18个血清型,共41种PFGE型别,其中山夫登堡沙门菌和肠炎沙门菌具有明显的优势带型;23株副溶血性弧菌PFGE型别较为分散。结论 3年间感染性腹泻患者致病菌的血清型和PFGE带型分布较为广泛,应注意沙门菌属和志贺菌属细菌的PFGE优势菌型,警惕其引发的感染性腹泻暴发流行。 相似文献
988.
Rodolfo Gonzalez Camargo Daniela Mendes dos Reis Riccardi Henrique Quintas Teixeira Ribeiro Luiz Carlos Carnevali Jr. Emidio Marques de Matos-Neto Lucas Enjiu Rodrigo Xavier Neves Joanna Darck Carola Correia Lima Raquel Galv?o Figuerêdo Paulo Sérgio Martins de Alcantara Linda Maximiano José Otoch Miguel Luiz Batista Jr. Gerhard Püschel Marilia Seelaender 《Nutrients》2015,7(6):4465-4479
989.
Are 5‐HT3 antagonists effective in obsessive–compulsive disorder? A systematic review of literature 下载免费PDF全文
Daniele Serata Georgios D. Kotzalidis Chiara Rapinesi Delfina Janiri Simone Di Pietro Gemma Callovini Daria Piacentino Carlotta Gasperoni Roberto Brugnoli Vittoria Rachele Ferri Nicoletta Girardi Roberto Tatarelli Stefano Ferracuti Gloria Angeletti Paolo Girardi Antonio Del Casale 《Human psychopharmacology》2015,30(2):70-84
990.
Increased plasma levels of soluble TNF receptors 1 and 2 in bipolar depression and impact of lithium treatment 下载免费PDF全文