全文获取类型
收费全文 | 7253篇 |
免费 | 548篇 |
国内免费 | 65篇 |
专业分类
耳鼻咽喉 | 71篇 |
儿科学 | 193篇 |
妇产科学 | 225篇 |
基础医学 | 1025篇 |
口腔科学 | 101篇 |
临床医学 | 629篇 |
内科学 | 1814篇 |
皮肤病学 | 197篇 |
神经病学 | 924篇 |
特种医学 | 265篇 |
外科学 | 648篇 |
综合类 | 13篇 |
预防医学 | 402篇 |
眼科学 | 75篇 |
药学 | 532篇 |
中国医学 | 15篇 |
肿瘤学 | 737篇 |
出版年
2023年 | 118篇 |
2022年 | 84篇 |
2021年 | 323篇 |
2020年 | 254篇 |
2019年 | 313篇 |
2018年 | 317篇 |
2017年 | 255篇 |
2016年 | 296篇 |
2015年 | 343篇 |
2014年 | 394篇 |
2013年 | 498篇 |
2012年 | 751篇 |
2011年 | 732篇 |
2010年 | 376篇 |
2009年 | 296篇 |
2008年 | 448篇 |
2007年 | 395篇 |
2006年 | 376篇 |
2005年 | 304篇 |
2004年 | 259篇 |
2003年 | 220篇 |
2002年 | 158篇 |
2001年 | 33篇 |
2000年 | 33篇 |
1999年 | 27篇 |
1998年 | 26篇 |
1997年 | 15篇 |
1996年 | 15篇 |
1995年 | 12篇 |
1994年 | 5篇 |
1993年 | 13篇 |
1992年 | 32篇 |
1991年 | 13篇 |
1990年 | 11篇 |
1989年 | 15篇 |
1988年 | 9篇 |
1987年 | 15篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1984年 | 11篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1974年 | 3篇 |
1969年 | 3篇 |
1968年 | 3篇 |
1967年 | 5篇 |
1966年 | 8篇 |
1965年 | 4篇 |
排序方式: 共有7866条查询结果,搜索用时 15 毫秒
1.
2.
3.
Marco Bologna Giuseppina Calareso Carlo Resteghini Silvana Sdao Eros Montin Valentina Corino Luca Mainardi Lisa Licitra Paolo Bossi 《NMR in biomedicine》2022,35(4):e4265
In this paper, several radiomics-based predictive models of response to induction chemotherapy (IC) in sinonasal cancers (SNCs) are built and tested. Models were built as a combination of radiomic features extracted from three types of MRI images: T1-weighted images, T2-weighted images and apparent diffusion coefficient (ADC) maps. Fifty patients (aged 54 ± 12 years, 41 men) were included in this study. Patients were classified according to their response to IC (25 responders and 25 nonresponders). Not all types of images were acquired for all of the patients: 49 had T1-weighted images, 50 had T2-weighted images and 34 had ADC maps. Only in a subset of 33 patients were all three types of image acquired. Eighty-nine radiomic features were extracted from the MRI images. Dimensionality reduction was performed by using principal component analysis (PCA) and by selecting only the three main components. Different algorithms (trees ensemble, K-nearest neighbors, support vector machine, naïve Bayes) were used to classify the patients as either responders or nonresponders. Several radiomic models (either monomodality or multimodality obtained by a combination of T1-weighted, T2-weighted and ADC images) were developed and the performance was assessed through 100 iterations of train and test split. The area under the curve (AUC) of the models ranged from 0.56 to 0.78. Trees ensemble, support vector machine and naïve Bayes performed similarly, but in all cases ADC-based models performed better. Trees ensemble gave the highest AUC (0.78 for the T1-weighted+T2-weighted+ADC model) and was used for further analyses. For trees ensemble, the models based on ADC features performed better than those models that did not use those features (P < 0.02 for one-tail Hanley test, AUC range 0.68–0.78 vs 0.56–0.69) except the T1-weighted+ADC model (AUC 0.71 vs 0.69, nonsignificant differences). The results suggest the relevance of ADC-based radiomics for prediction of response to IC in SNCs. 相似文献
4.
Valentina Guercio Francesca Donato Claudio Pelucchi Federica Verga Valter Passini Carlotta Galeone Eva Negri Giacomo Garzaro Paolo Boffetta Carlo La Vecchia Alessandra Tavani Enrico Pira 《La Medicina del lavoro》2019,110(5):342
Background::Soft tissue sarcoma (STS) is a heterogeneous group of rare neoplasms whose aetiology is largely unknown. Dioxin and dioxin-like compounds, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and polychlorinated biphenyls (PCBs), are potential risk factors for STS.Objectives:To investigate the relation of 17 PCBs congeners, assessed in human plasma, with STS risk.Methods:We conducted a case-control study in Italy, including 52 STS cases and 99 hospital-based controls. Selected PCB were extracted by high-performance liquid chromatography (HPLC) and measured with gas chromatography-mass spectrometry (GC-MS). Odds ratios (OR), and the corresponding 95% confidence intervals (CI), were estimated through multivariate logistic regression models.Results:The most frequently detected PCB congeners were 138, 170, 180 and 149 (detected in 40-77% of controls). The OR for the sum of all 17 PCB congeners was 1.20 (95% CI 0.50-2.92). In categorical analysis no consistent association was found for individual congeners and for groups based on Wolff’s classification or the degree of chlorination. For continuous estimates, borderline positive associations emerged for Wolff’s groups 2A (OR 1.23, 95% CI 0.97-1.55), 2B (OR 1.34, 95% CI 1.00-1.77, and 3 (OR 1.19, 95% CI 0.96-1.49), for moderately (OR 1.20, 95% CI 0.96-1.51) and highly (OR 1.18, 95% CI 0.99-1.41) chlorinated PCBs, and for congeners 170 (OR 1.26, 95% CI 0.98-1.63), 180 (OR 1.26, 95% CI 0.97-1.64) and 138 (OR 1.45, 95% CI 1.02-2.04).Discussion:Most associations between PCBs and STS risk were not significant, but, given the limited sample size, we cannot exclude moderate associations.Key words: Soft tissue sarcoma, polychlorinated biphenyls, epidemiology, environmental risk factors, chemical contaminants, case-control study 相似文献
5.
6.
Background
Many patients undergoing below knee amputations (BKA) return for subsequent unplanned operations, hospital readmission, or postoperative complications. This unplanned medical management negatively impacts both patient outcomes and our healthcare system. This study primarily investigates the risk factors for unplanned reoperation following BKA.Methods
Below knee amputations from the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database from the years 2012–2014 were identified by CPT code 27880 for amputation through the tibia and fibula. Our query identified 4631 BKA cases, including 30 day complications. Multivariate logistic regression modeling was performed on several patient demographic and disease factors to assess for independent predictors of unplanned reoperation. Secondary outcomes of unplanned and related readmissions (related to the procedure), major complications, minor complications, and mortality were also included in the analysis.Results
Of 4631 BKAs identified, 9.63% (446/4631) underwent unplanned reoperations and 8.75% (405/4631) had unplanned and related readmissions. Major complications were experienced by 12.8% (593/4631) and minor complications by 8.7% (401/4631). Thirty day mortality rate was 5.14% (238/4631). The most common procedures for unplanned operations were thigh amputations (128/446, 28.7%), debridement/secondary closure (114/446, 25.6%), and revision leg amputations (46/446, 10.32%). Factors associated with an increased risk of unplanned reoperation included patients transferred from another facility (Adjusted Odds Ratio [AOR]?=?1.28; p?=?.04), recent smokers (AOR?=?1.34; p?=?.02), bleeding disorder (AOR?=?1.30; p?=?.02), and preoperative ventilator use (AOR?=?2.38; p?=?.01).Conclusion
Patients that were ongoing/recent smokers, had diagnosed bleeding disorders, required preoperative ventilator use, or were transferred in from another facility were associated with the highest risks of reoperation following BKA. This patient population experiences high rates of reoperation, readmission, complication, and mortality. 相似文献7.
Valentina Becherucci Stefano Ermini Luisa Piccini Silvia Bisin Valentina Gori Francesca Gentile Riccardo Ceccantini Elena De Rienzo Barbara Bindi Paola Pavan Vanessa Cunial Elisa Allegro Francesca Brugnolo Daniela Maggio Daniela Calzolari Erika Maccarelli Silvia Galli Sonia Muricci Marco Berchielli Veronica Tintori Iacopo Sardi Franco Bambi 《Journal of clinical apheresis》2020,35(5):406-412
8.
9.
10.