全文获取类型
收费全文 | 852篇 |
免费 | 66篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 25篇 |
妇产科学 | 10篇 |
基础医学 | 116篇 |
口腔科学 | 5篇 |
临床医学 | 111篇 |
内科学 | 196篇 |
皮肤病学 | 13篇 |
神经病学 | 107篇 |
特种医学 | 21篇 |
外科学 | 75篇 |
综合类 | 7篇 |
一般理论 | 2篇 |
预防医学 | 123篇 |
眼科学 | 16篇 |
药学 | 37篇 |
肿瘤学 | 56篇 |
出版年
2024年 | 2篇 |
2023年 | 27篇 |
2022年 | 43篇 |
2021年 | 99篇 |
2020年 | 55篇 |
2019年 | 64篇 |
2018年 | 67篇 |
2017年 | 33篇 |
2016年 | 31篇 |
2015年 | 23篇 |
2014年 | 31篇 |
2013年 | 48篇 |
2012年 | 75篇 |
2011年 | 66篇 |
2010年 | 25篇 |
2009年 | 23篇 |
2008年 | 45篇 |
2007年 | 37篇 |
2006年 | 32篇 |
2005年 | 30篇 |
2004年 | 16篇 |
2003年 | 13篇 |
2002年 | 16篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1977年 | 1篇 |
1964年 | 1篇 |
1962年 | 1篇 |
1960年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有922条查询结果,搜索用时 281 毫秒
71.
Chloe E.H. Scott Matilda F.R. Powell-Bowns Deborah J. MacDonald Philip M. Simpson Frazer A. Wade 《The Journal of arthroplasty》2018,33(7):2203-2209
Background
The aim of this study is to investigate differences in implant requirement, outcomes, and re-revision when total knee arthroplasty (TKA) was performed following unicompartmental knee arthroplasties (UKAs) with metal-backed (MB) compared to all-polyethylene (AP) tibial components.Methods
Retrospective study of 60 UKAs converted to 60 TKAs at mean 7.3 years (0.1 to 17) after implantation in 55 patients (mean age, 64 [49-83]; 44% male): 44 MB and 16 AP. TKA implant requirement was investigated in addition to mode of failure, Oxford Knee Score, and TKA survival at mean 5.4 years (0.5 to 17).Results
Progression of osteoarthritis was the commonest mode of failure in MB UKAs (P = .03) and unexplained pain in AP (P = .011) where revisions were performed earlier (4.8 ± 3.2 vs 8.2 ± 4.5, P = .012). In 56 of 60 (93%) cases, unconstrained TKA implants were used. The use of standard cruciate-retaining TKAs without augments or stems was less likely following MB UKA compared to AP (12 of 38 [32%] vs 10/14 [71%], P = .013). Specifically MB UKA implants were associated with more tibial stem use (P = .04) and more use of cruciate-substituting polyethylene (P = .05). There was no difference in the use of constrained implants. Multivariate analysis showed tibial resection depth to predict stem requirement. Seven were re-revised giving 7-year TKA survival: from MB UKA 70.3 (95% CI, 47.0 to 93.6) and from AP UKA 87.5 (95% CI, 64.6 to 100; P = .191).Conclusion
MB UKA implants increase the chances of a complex revision requiring tibial stems and cruciate substitution but reduce the chances of early revision compared to AP UKA which often fail early with pain. 相似文献72.
Seerat Aziz MD Richard C. Cho MD Diana B. Baker MD Chloe Chhor MD Roy A. Filly MD 《Journal of ultrasound in medicine》2008,27(11):1559-1561
Objective. The purpose of this study was to assess outcomes in embryos with a crown‐rump length (CRL) of 5 mm or less without embryonic cardiac activity (ECA) among pregnant women with vaginal bleeding in the first trimester. Methods. A retrospective study of all first‐trimester sonograms in women with vaginal bleeding from 1999 to 2002 was conducted. Results. Thirty‐seven embryos without detectable ECA that had a CRL of 5 mm or less were identified. All resulted in pregnancy failure. The breakdown of these embryos by CRL was as follows: 13 were 5 mm; 10 ranged from 4 to 4.9 mm; 11 ranged from 3 to 3.9 mm; and 3 ranged from 2 to 2.9 mm. Conclusions. In pregnant women with vaginal bleeding, embryos of 5 mm and smaller without a heartbeat all resulted in pregnancy failure. 相似文献
73.
74.
Image distortion correction in fMRI: A quantitative evaluation 总被引:7,自引:0,他引:7
A well-recognized problem with the echo-planar imaging (EPI) technique most commonly used for functional magnetic resonance imaging (fMRI) studies is geometric distortion caused by magnetic field inhomogeneity. This makes it difficult to achieve an accurate registration between a functional activation map calculated from an EPI time series and an undistorted, high resolution anatomical image. A correction method based on mapping the spatial distribution of field inhomogeneities can be used to reduce these distortions. This approach is attractive in its simplicity but requires postprocessing to improve the robustness of the acquired field map and reduce any secondary artifacts. Furthermore, the distribution of the internal magnetic field throughout the head is position dependent resulting in an interaction between distortion and head motion. Therefore, a single field map may not be sufficient to correct for the distortions throughout a whole fMRI time series. In this paper we present a quantitative evaluation of image distortion correction for fMRI at 2T. We assess (i) methods for the acquisition and calculation of field maps, (ii) the effect of image distortion correction on the coregistration between anatomical and functional images, and (iii) the interaction between distortion and head motion, assessing the feasibility of using field maps to reduce this effect. We propose that field maps with acceptable noise levels can be generated easily using a dual echo-time EPI sequence and demonstrate the importance of distortion correction for anatomical coregistration, even for small distortions. Using a dual echo-time series to generate a unique field map at each time point, we characterize the interaction between head motion and geometric distortion. However, we suggest that the variance between successively measured field maps introduces additional unwanted variance in the voxel time-series and is therefore not adequate to correct for time-varying distortions. 相似文献
75.
William Bonadio Syeda Shahid Lior Vardi Carly Buckingham Allison Kornblatt Chloe Free Peter Homel 《Journal of pediatric surgery》2018,53(3):441-445
Importance
Appendicitis is a common, potentially serious pediatric disease. An important factor in determining management strategy [whether/when to perform appendectomy, duration of antibiotic therapy/hospitalization, etc.] and predicting outcome is distinguishing whether perforation is present.Objective
The objective was to determine efficacy of commonly assessed pre-operative variables in stratifying perforation risk in children with appendicitis.Design
A retrospective analysis of consecutive cases was performed.Setting
The setting was a large urban hospital pediatric emergency department.Participants
Four hundred forty-eight consecutive cases of CT [computerized tomography]-confirmed pediatric appendicitis during a 6-year period in an urban pediatric ED [emergency department]: 162 with perforation and 286 non-perforated.Main outcome(s) and measure(s)
To determine efficacy of clinical and laboratory variables with distinguishing perforation outcome in children with appendicitis.Results
Regression analysis identified 3 independently significant variables associated with perforation outcome – and determined their ideal threshold values: duration of symptoms > 1 day; ED-measured fever [body temperature > 38.0 °C]; CBC WBC absolute neutrophil count > 13,000/mm3. The resulting multivariate ROC [receiver operating characteristic] curve after applying these threshold values gave an AUC [area under curve] of 89% for perforation outcome [p < 0.001]. Risk for perforation was additive with each additional predictive variable exceeding its threshold value, linearly increasing from 7% with no variable present to 85% when all 3 variables are present.Conclusions
A pre-operative scoring system comprised of 3 commonly assessed clinical/laboratory variables is useful in stratifying perforation risk in children with appendicitis.Physicians can utilize these factors to gauge pre-operative risk for perforation in children with appendicitis, which can potentially aid in planning subsequent management strategy.Level of evidence
III. 相似文献76.
Paul D.E Miller Thushan I. de Silva Hayley Leonard Chloe Anthias Katja Hoschler Kathryn Goddard Karl Peggs Alejandro Madrigal John A. Snowden 《Vaccine》2019,37(3):452-457
Traditionally, immune response to influenza vaccines has been measured using the haemagglutination inhibition (HAI) assay. A broader repertoire of techniques including the sensitive viral microneutralization (VMN) assay is now recommended by the European Medicines Agency (EMA). Comparing HAI and VMN, we determined immune response to a trivalent 2015–2016 seasonal inactivated influenza vaccine (SIIV) administered to 28 recipients of allogeneic haematopoietic stem cell transplant (HSCT). Vaccination was within the first-year post-transplant at a median of 78.5 (24–363) days. The proportion of patients with baseline and post-vaccination HAI titres?≥?1:40 were 28.6% and 25% for A(H1N1)pdm09, 14.3% at both timepoints for A(H3N2), and 32.1% and 25% for B(Phuket). Pre and Post-vaccination geometric mean titres(GMT) were higher by VMN than HAI for A(H1N1)pdm09 and A(H3N2), but lower for B(Phuket)(p=<0.05). Geometric mean ratios(GMR) of baseline and post-vaccination titres were similar by HAI and VMN(p?>?0.05) for all components. A single seroconversion to A(H1N1) was detected by ELISA-VMN. None of patient age, lymphocyte count, days from transplant to vaccination, donor type, or graft-versus-host disease (GVHD) or immunosuppressive therapy (IST) at vaccination correlated with baseline or post-vaccination titres by either assay. This absence of seroresponse to SIIV in the first-year post HSCT highlights the need for novel immunogenic vaccination formulations and schedules in this high-risk population. 相似文献
77.
78.
79.
Chloe Christina Kimball Christine Ida Nichols Joshua Greene Vose Anne Warren Peled 《Annals of surgical oncology》2018,25(13):3867-3873
Background
Oncoplastic breast surgery aims to optimize efficacy of surgical resection and cosmesis to maximize patient satisfaction; however, despite the benefits, oncoplastic techniques have not been widely adopted in the US. This study examined trends in the incidence of lumpectomy (partial mastectomy) with or without oncoplastic techniques from 2011 to 2016.Methods
This was a retrospective analysis of claims from the Optum Clinformatics database (January 2010–March 2017). Female patients with no history of breast surgery in the prior year were categorized into three independent cohorts: isolated lumpectomy (Lx), lumpectomy with tissue transfer (LxTT), or lumpectomy with mammaplasty and/or mastopexy (LxMM). Oncoplastic techniques (in cohorts two and three) were performed at either time of the initial lumpectomy or during 90-day follow-up.Results
Overall, 19,253 patients met the inclusion criteria (91.1% Lx, 5.2% LxTT, and 3.7% LxMM). Significantly fewer patients with Lx had a family history of breast cancer compared with patients with oncoplastic techniques (26.4% vs. 33.7% and 37.9%, respectively; p?<?0.001). The incidence of Lx declined significantly from 2011 (92.9%) to 2016 (88.1%), while LxTT and LxMM increased from 4.2 to 7.2% and 2.8 to 4.7%, respectively (both p?<?0.001). The greatest utilization of oncoplastic techniques was observed in the Pacific census division (19.2%), while lowest utilization was in the East South Central division (3.2%; p?<?0.001).Conclusions
While increased adoption of oncoplastic techniques was observed, the compound annual growth rate remained below 10% and varied significantly by region. Further adoption of oncoplastic techniques is necessary to improve cosmetic outcomes and patient satisfaction following breast-conserving surgery.80.