全文获取类型
收费全文 | 16054篇 |
免费 | 895篇 |
国内免费 | 98篇 |
专业分类
耳鼻咽喉 | 191篇 |
儿科学 | 294篇 |
妇产科学 | 275篇 |
基础医学 | 2086篇 |
口腔科学 | 887篇 |
临床医学 | 1386篇 |
内科学 | 3741篇 |
皮肤病学 | 254篇 |
神经病学 | 1588篇 |
特种医学 | 421篇 |
外科学 | 2565篇 |
综合类 | 80篇 |
一般理论 | 8篇 |
预防医学 | 1059篇 |
眼科学 | 281篇 |
药学 | 933篇 |
中国医学 | 52篇 |
肿瘤学 | 946篇 |
出版年
2023年 | 131篇 |
2022年 | 274篇 |
2021年 | 518篇 |
2020年 | 300篇 |
2019年 | 417篇 |
2018年 | 499篇 |
2017年 | 377篇 |
2016年 | 373篇 |
2015年 | 444篇 |
2014年 | 637篇 |
2013年 | 803篇 |
2012年 | 1273篇 |
2011年 | 1262篇 |
2010年 | 703篇 |
2009年 | 638篇 |
2008年 | 1041篇 |
2007年 | 1029篇 |
2006年 | 943篇 |
2005年 | 895篇 |
2004年 | 782篇 |
2003年 | 693篇 |
2002年 | 661篇 |
2001年 | 197篇 |
2000年 | 170篇 |
1999年 | 188篇 |
1998年 | 151篇 |
1997年 | 99篇 |
1996年 | 101篇 |
1995年 | 76篇 |
1994年 | 76篇 |
1993年 | 67篇 |
1992年 | 107篇 |
1991年 | 93篇 |
1990年 | 82篇 |
1989年 | 92篇 |
1988年 | 79篇 |
1987年 | 68篇 |
1986年 | 75篇 |
1985年 | 66篇 |
1984年 | 42篇 |
1983年 | 33篇 |
1982年 | 28篇 |
1981年 | 34篇 |
1980年 | 30篇 |
1979年 | 38篇 |
1977年 | 21篇 |
1975年 | 30篇 |
1974年 | 34篇 |
1973年 | 21篇 |
1972年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
Willy Baccaglini Felipe A. Glina Cristiano Linck Pazeto Luis G. Medina Fernando Korkes Wanderley M. Bernardo Rene Sotelo Sidney Glina Giancarlo Marra Marco Moschini Xavier Cathelineau Rafael Sanchez-Salas 《Clinical genitourinary cancer》2021,19(1):3-11.e1
This meta-analysis focuses on the accuracy of upgrading to clinically significant prostate cancer (PCa) by multiparametric magnetic resonance imaging-targeted biopsy (MRI-TB) versus systematic biopsy (SB). We searched the Medline, Embase, Cochrane Central Register of Controlled Trials, Web of Science, Scopus, and Literatura Latino Americana em Ciências da Saúde databases through January 2020 for comparative, retrospective/prospective, paired-cohort, and randomized clinical trials with paired comparisons. The population consisted of patients with low-risk PCa in active surveillance with at least 1 index lesion on imaging. We evaluated the quality of evidence by using the Quality Assessment of Diagnostic Accuracy Studies-2 score. Group comparisons considered the differences between the area under the curve summary receiver operating characteristic curve in a 2-tailed method. We also compared the positive predictive value of the best single method (MRI-TB or SB) and the referral study test (combined biopsy, a combination of MRI-TB and SB). The meta-analysis included 6 studies enrolling 741 patients. The pooled sensitivity for the 2 groups was 0.79 (95% confidence interval, 0.74-0.83; I2 = 75%) and 0.67 (95% confidence interval, 0.63-0.74; I2 = 55.4%), respectively. The area under the curve for the MRI-TB and SB groups were 0.99 and 0.92 (P < .001), respectively. The positive predictive value for the MRI-TB and combined biopsy groups were similar. The accumulated evidence suggests better results for MRI-TB compared with SB. Therefore, use of MRI-TB alone may be preferable in patients in active surveillance harboring low-risk PCa. 相似文献
3.
Del Lama Rafael Silva Candido Raquel Mariana Chiari-Correia Natália Santana Nogueira-Barbosa Marcello Henrique de Azevedo-Marques Paulo Mazzoncini Tinós Renato 《Journal of digital imaging》2022,35(3):446-458
Journal of Digital Imaging - Vertebral Compression Fracture (VCF) occurs when the vertebral body partially collapses under the action of compressive forces. Non-traumatic VCFs can be secondary to... 相似文献
4.
5.
Miguel A. Sanz Pau Montesinos Haesook T. Kim Guillermo J. Ruiz-Argüelles María S. Undurraga María R. Uriarte Lem Martínez Rafael H. Jacomo Homero Gutiérrez-Aguirre Raul A. M. Melo Rosane Bittencourt Ricardo Pasquini Katia Pagnano Evandro M. Fagundes Edo Vellenga Alexandra Holowiecka Ana J. González-Huerta Pascual Fernández Javier De la Serna Salut Brunet Elena De Lisa José González-Campos José M. Ribera Isabel Krsnik Arnold Ganser Nancy Berliner Raul C. Ribeiro Francesco Lo-Coco Bob L?wenberg Eduardo M. Rego 《Annals of hematology》2015,94(8):1347-1356
6.
The difficulty of diagnosing NCSE in clinical practice; external validation of the Salzburg criteria
Rianne J. M. Goselink Jeroen J. van Dillen Marjolein Aerts Johan Arends Charlotte van Asch Inge van der Linden Jaco Pasman Christiaan G. J. Saris Machiel Zwarts Nens van Alfen 《Epilepsia》2019,60(8):e88-e92
To improve the diagnostic accuracy of electroencephalography (EEG) criteria for nonconvulsive status epilepticus (NCSE), external validation of the recently proposed Salzburg criteria is paramount. We performed an external, retrospective, diagnostic accuracy study of the Salzburg criteria, using EEG recordings from patients with and without a clinical suspicion of having NCSE. Of the 191 EEG recordings, 12 (12%) was classified as an NCSE according to the reference standard. In the validation cohort, sensitivity was 67% and specificity was 89%. The positive predictive value was 47% and the negative predictive value was 95%. Ten patients in the control group (n = 93) were false positive, resulting in a specificity of 89.2%. The interrater agreement between the reference standards and between the scorers of the Salzburg criteria was moderate; disagreement occurred mainly in patients with an epileptic encephalopathy. The Salzburg criteria showed a lower diagnostic accuracy in our external validation study than in the original design, suggesting that they cannot replace the current practice of careful weighing of both clinical and EEG information on an individual basis. 相似文献
7.
Zinc sulfate addition to glass-ionomer-based cements: influence on physical and antibacterial properties, zinc and fluoride release. 总被引:5,自引:0,他引:5
Prudencio W R Osinaga Rosa Helena M Grande Rafael Y Ballester Maria Regina L Simionato Célia Regina M Delgado Rodrigues Antonio Muench 《Dental materials》2003,19(3):212-217
OBJECTIVES: The aim of this study is to evaluate the effect of ZnSO(4) addition to a conventional glass ionomer and a resin-modified glass ionomer on solubility, flexural strength, zinc and fluoride (F) release, and Streptococcus mutans growth inhibition. METHODS: 5 or 10% ZnSO(4) was added to Vitremer and Ketac-Fil powders. Solubility test was performed based on ISO 7489. Flexural strength was determined by 3-point bending test based on ISO 4049. Zn release/uptake was determined by atomic emission spectrometry; F release/uptake was measured using a F-specific electrode. Both release measurements were performed for 15 d before and 15 d after recharging. Antibacterial test was conducted according to agar plate methods against S. mutans, by measuring the inhibition halos in 1-h and 15-d specimens. Data were analyzed by ANOVA. RESULTS: Solubility increased with higher ZnSO(4) content, but remained below the ISO 7489 limit. Flexural strength was not affected by ZnSO(4) addition, and Vitremer performed better than Ketac-Fil. The control materials released no zinc. Vitremer with 10% ZnSO(4) released the highest amount of zinc. Fluoride release was similar for Ketac-Fil and Vitremer. In both cases, the highest amounts were released in the first 24 h. The growth inhibition halo of S. mutans was similar for both materials with highest content of ZnSO(4) and occurred only with 1-h specimens. SIGNIFICANCE: Zinc addition decreased microorganisms growth and improved fluoride release, without significantly affecting the materials' flexural strength and solubility. 相似文献
8.
9.
To improve the appropriateness and efficiency of diagnostic serological tests and subsequent antibiotic treatment, clinical data from 102 patients with unclassified arthritis were analysed to investigate whether the presence of positive IgG antibodies to Borrelia burgdorferi could be predicted. The clinical data were blindly ranked from 1 to 4 (1, Lyme arthritis unlikely; 4, Lyme arthritis very likely). Antibodies to B burgdorferi were positive in nine of 102 patients (9%). Six of 15 (40%) patients with rank numbers 3 and 4 were positive for antibodies to B burgdorferi, in contrast with only three of 87 (3%) patients with rank numbers 1 and 2. The likelihood ratio of positive Lyme serology for patients ranked 3 and 4 was 12.0, for patients ranked 2 to 4, 4.5, and for patients with arthritis of the knee, 3.0. These likelihood ratios were associated with a post-test probability of 55, 30, and 20% respectively. The clinical history in patients with unclassified arthritis can largely predict the presence of antibodies to B burgdorferi. The absolute value of a likelihood ratio can be a contributing factor in deciding to request tests for antibodies to B burgdorferi in patients with unclassified arthritis. 相似文献
10.