全文获取类型
收费全文 | 1231篇 |
免费 | 116篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 51篇 |
妇产科学 | 23篇 |
基础医学 | 160篇 |
口腔科学 | 44篇 |
临床医学 | 156篇 |
内科学 | 209篇 |
皮肤病学 | 66篇 |
神经病学 | 33篇 |
特种医学 | 158篇 |
外科学 | 173篇 |
综合类 | 30篇 |
预防医学 | 65篇 |
眼科学 | 15篇 |
药学 | 81篇 |
中国医学 | 4篇 |
肿瘤学 | 83篇 |
出版年
2023年 | 12篇 |
2021年 | 16篇 |
2020年 | 15篇 |
2019年 | 16篇 |
2018年 | 26篇 |
2017年 | 17篇 |
2016年 | 18篇 |
2015年 | 28篇 |
2014年 | 45篇 |
2013年 | 53篇 |
2012年 | 55篇 |
2011年 | 70篇 |
2010年 | 53篇 |
2009年 | 73篇 |
2008年 | 67篇 |
2007年 | 58篇 |
2006年 | 50篇 |
2005年 | 55篇 |
2004年 | 56篇 |
2003年 | 38篇 |
2002年 | 39篇 |
2001年 | 30篇 |
2000年 | 36篇 |
1999年 | 33篇 |
1998年 | 27篇 |
1997年 | 42篇 |
1996年 | 41篇 |
1995年 | 29篇 |
1994年 | 25篇 |
1993年 | 20篇 |
1992年 | 13篇 |
1991年 | 9篇 |
1990年 | 14篇 |
1989年 | 20篇 |
1988年 | 11篇 |
1987年 | 7篇 |
1986年 | 13篇 |
1985年 | 13篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 11篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1973年 | 5篇 |
1971年 | 5篇 |
1970年 | 6篇 |
1968年 | 4篇 |
1966年 | 9篇 |
排序方式: 共有1356条查询结果,搜索用时 31 毫秒
1.
2.
Brenda Happell RN Cert Psych Nurs BA DipEd MEd PhD FACMHN Shifra Waks BA MIHP B Int Global Stud Aine Horgan PhD MSc BNS PGCert T&L RPN Sonya Greaney DipSPH PG Cert Peer Support Fionnuala Manning John Goodwin MA PGDip Bsc BA ALCM DipMgmt RPN Julia Bocking BPhil B Soc & Comm Stud Brett Scholz BHSci PhD Elisabeth Hals MA Arild Granerud PhD Rory Doody B.Soc.Sc. Chris Platania-Phung BA PhD Martha Griffin H. Dip in Community Youth Work Siobhan Russell BSc RPN PhD Liam MacGabhann BSc MSc DrNursSci Jarmo Pulli Annaliina Vatula BA Graeme Browne RN MHN PhD FACMHN Kornelis Jan van der Vaart BN MSci Jerry Allon Einar Bjornsson Heikki Ellilä RN MNSc PhD Mari Lahti MNSc PhD Pall Biering PhD 《Perspectives in psychiatric care》2020,56(4):811-819
3.
4.
Whang CZ Bister D Sherriff M 《European journal of orthodontics》2011,33(6):732; author reply 732-732; author reply 733
This study compared peak insertion torque values of six commercially available self-drilling mini-implants [Mini Spider? screw (1.5 × 8 mm), Infinitas? (1.5 × 9 mm), Vector TAS? (1.4 × 8 mm), Dual Top? (1.6 × 8 mm), Tomas Pin? (1.6 × 8 mm), and Ortho-Easy? (1.7 × 6, 8, and 10 mm)]. Twenty implants each were drilled into acrylic rods at a speed of 8 rpm using a motorized torque measurement stand, and the values were recorded in Newton centimetres (Ncm). A further 20 Ortho-Easy? implants with a length of 6 and 10 mm were tested at 8 rpm; 20 implants of 6 mm length were also tested at 4 rpm. Kaplan-Meier estimates of the peak torque values were compared using the log-rank test with multiple comparisons evaluated by Sidak's test. There were significant differences in the maximum torque values for different mini-implants with the same length. The Mini Spider? screw and Infinitas? showed the lowest average torque values (6.5 and 12.4 Ncm) compared with Vector TAS?, Dual ToP?, Tomas Pin?, and Ortho-Easy? (30.9, 29.4, 25.4, and 24.8 Ncm, respectively). There was no correlation between the diameter of the implants and torque values. The Tomas Pin? showed the largest standard deviation (7.7 Ncm) and the Dual Top? implant the smallest (0.6 Ncm). Different insertion speeds did not result in significant differences in peak torque values but the 6 mm mini-implants showed significantly higher torque values than the 8 and 10 mm implants. Using a 'torque limiting' screwdriver or pre-drilling cortical bone to reduce insertion, torque appears justified for some of the tested implants. 相似文献
5.
OBJECTIVE: To assess the feasibility of using archival oral mucosal tissue to examine gene expression at the ribonucleic acid (RNA) level.
MATERIALS AND METHODS: We describe the isolation of RNA from 8 nm sections of formalin-fixed paraffin-embedded oral mucosal tissue. RNA was reverse transcribed and three candidate genes amplified by polymerase chain reaction (PCR). The ribosomal protein S14 gene is a housekeeping gene which has been used as an internal standard in several quantitative PCR protocols. The thymidine kinase (TK) gene is expressed at low levels in most tissues and, with a well-documented genomic organisation, is a useful tool for discrimination between genomic DNA and cDNA. The RIa gene is reported to be overexpressed in many cancer cell lines, in malignant tissue and in vitro transformed cellS. RESULTS: The S14 gene, the TK gene and the RIα gene of the cAMP-dependent protein kinase (PKA) were amplified successfully from formalin-fixed paraffin-embedded tissue sections. The TK primer pair is a useful additional tool in the unambiguous identification of RNA-derived species.
CONCLUSION: RNA suitable for reverse transcribed (RT)-PCR was extracted from archival oral mucosal tissue. This should permit rapid sequence analysis of transcribed tumor suppressor genes and oncogenes in this material. Furthermore, the RT-PCR approach described may allow quantification of gene expression in oral mucosal archival material processed in a standard fashion. 相似文献
MATERIALS AND METHODS: We describe the isolation of RNA from 8 nm sections of formalin-fixed paraffin-embedded oral mucosal tissue. RNA was reverse transcribed and three candidate genes amplified by polymerase chain reaction (PCR). The ribosomal protein S14 gene is a housekeeping gene which has been used as an internal standard in several quantitative PCR protocols. The thymidine kinase (TK) gene is expressed at low levels in most tissues and, with a well-documented genomic organisation, is a useful tool for discrimination between genomic DNA and cDNA. The RIa gene is reported to be overexpressed in many cancer cell lines, in malignant tissue and in vitro transformed cellS. RESULTS: The S14 gene, the TK gene and the RIα gene of the cAMP-dependent protein kinase (PKA) were amplified successfully from formalin-fixed paraffin-embedded tissue sections. The TK primer pair is a useful additional tool in the unambiguous identification of RNA-derived species.
CONCLUSION: RNA suitable for reverse transcribed (RT)-PCR was extracted from archival oral mucosal tissue. This should permit rapid sequence analysis of transcribed tumor suppressor genes and oncogenes in this material. Furthermore, the RT-PCR approach described may allow quantification of gene expression in oral mucosal archival material processed in a standard fashion. 相似文献
6.
Aetiological factors for oral manifestations of HIV 总被引:2,自引:0,他引:2
GD Palmer PG Robinson SJ Challacombe W Birnbaum D Croser PL Erridge T Hodgson D Lewis A McLaren JM Zakrzewska 《Oral diseases》1996,2(3):193-197
OBJECTIVES: Describe the oral diseases in HIV-infected individuals in London, UK and identify social and medical factors related to the presence of specific oral diseases.
DESIGN: Cross-sectional analytic study.
SETTING: Dental clinics.
SUBJECTS: Consecutive sample of 456 patients with HIV infection.
METHODS: Social and medical history and clinical examinations. Univariate and logistic regression analysis.
OUTCOMES: Presence of HIV-associated oral disease.
RESULTS: 80% of patients with AIDS and 50% of patients with HIV had a specific oral disease. The most common diseases were hairy leukoplakia (30%), erythematous candidiasis (24%), pseudomembranous candidiasis (14%), angular chielitis (6%), necrotising periodontal disease (8%) and non-recurrent ulceration (6%).
CONCLUSIONS: The presence of erythematous candidiasis was not related to advanced HIV disease. Pseudomembranous candidiasis, hairy leukoplakia and mucosal ulceration were significantly associated with advanced HIV disease. Smoking was also identified as a strong aetiological factor in oral diseases. Longitudinal studies are required to further explore the prognostic significance of oral diseases in HIV infection. 相似文献
DESIGN: Cross-sectional analytic study.
SETTING: Dental clinics.
SUBJECTS: Consecutive sample of 456 patients with HIV infection.
METHODS: Social and medical history and clinical examinations. Univariate and logistic regression analysis.
OUTCOMES: Presence of HIV-associated oral disease.
RESULTS: 80% of patients with AIDS and 50% of patients with HIV had a specific oral disease. The most common diseases were hairy leukoplakia (30%), erythematous candidiasis (24%), pseudomembranous candidiasis (14%), angular chielitis (6%), necrotising periodontal disease (8%) and non-recurrent ulceration (6%).
CONCLUSIONS: The presence of erythematous candidiasis was not related to advanced HIV disease. Pseudomembranous candidiasis, hairy leukoplakia and mucosal ulceration were significantly associated with advanced HIV disease. Smoking was also identified as a strong aetiological factor in oral diseases. Longitudinal studies are required to further explore the prognostic significance of oral diseases in HIV infection. 相似文献
7.
8.
Hyun Gi Kim Yong Eun Chung Young Han Lee Jin-Young Choi Mi-Suk Park Myeong-Jin Kim Ki Whang Kim 《Yonsei medical journal》2015,56(1):253-261
Purpose
To investigate the optimal blending percentage of adaptive statistical iterative reconstruction (ASIR) in a reduced radiation dose while preserving a degree of image quality and texture that is similar to that of standard-dose computed tomography (CT).Materials and Methods
The CT performance phantom was scanned with standard and dose reduction protocols including reduced mAs or kVp. Image quality parameters including noise, spatial, and low-contrast resolution, as well as image texture, were quantitatively evaluated after applying various blending percentages of ASIR. The optimal blending percentage of ASIR that preserved image quality and texture compared to standard dose CT was investigated in each radiation dose reduction protocol.Results
As the percentage of ASIR increased, noise and spatial-resolution decreased, whereas low-contrast resolution increased. In the texture analysis, an increasing percentage of ASIR resulted in an increase of angular second moment, inverse difference moment, and correlation and in a decrease of contrast and entropy. The 20% and 40% dose reduction protocols with 20% and 40% ASIR blending, respectively, resulted in an optimal quality of images with preservation of the image texture.Conclusion
Blending the 40% ASIR to the 40% reduced tube-current product can maximize radiation dose reduction and preserve adequate image quality and texture. 相似文献9.
Trends and predictors of resection of the primary tumor for patients with stage IV colorectal cancer 下载免费PDF全文
10.