全文获取类型
收费全文 | 2599624篇 |
免费 | 201663篇 |
国内免费 | 6359篇 |
专业分类
耳鼻咽喉 | 34906篇 |
儿科学 | 86193篇 |
妇产科学 | 73006篇 |
基础医学 | 375223篇 |
口腔科学 | 74932篇 |
临床医学 | 241491篇 |
内科学 | 500396篇 |
皮肤病学 | 54246篇 |
神经病学 | 213514篇 |
特种医学 | 99228篇 |
外国民族医学 | 804篇 |
外科学 | 378202篇 |
综合类 | 62472篇 |
现状与发展 | 4篇 |
一般理论 | 958篇 |
预防医学 | 212791篇 |
眼科学 | 59054篇 |
药学 | 194578篇 |
9篇 | |
中国医学 | 5462篇 |
肿瘤学 | 140177篇 |
出版年
2018年 | 27433篇 |
2017年 | 21044篇 |
2016年 | 23213篇 |
2015年 | 26671篇 |
2014年 | 36778篇 |
2013年 | 56764篇 |
2012年 | 77229篇 |
2011年 | 81871篇 |
2010年 | 48045篇 |
2009年 | 45080篇 |
2008年 | 76577篇 |
2007年 | 80868篇 |
2006年 | 81499篇 |
2005年 | 79110篇 |
2004年 | 76711篇 |
2003年 | 73181篇 |
2002年 | 71536篇 |
2001年 | 116994篇 |
2000年 | 120894篇 |
1999年 | 102055篇 |
1998年 | 28854篇 |
1997年 | 26231篇 |
1996年 | 25960篇 |
1995年 | 25085篇 |
1994年 | 23566篇 |
1993年 | 22261篇 |
1992年 | 83419篇 |
1991年 | 81625篇 |
1990年 | 79449篇 |
1989年 | 76295篇 |
1988年 | 70972篇 |
1987年 | 69643篇 |
1986年 | 66416篇 |
1985年 | 63953篇 |
1984年 | 48091篇 |
1983年 | 41304篇 |
1982年 | 24693篇 |
1981年 | 21985篇 |
1979年 | 45122篇 |
1978年 | 31714篇 |
1977年 | 26536篇 |
1976年 | 25346篇 |
1975年 | 26570篇 |
1974年 | 32470篇 |
1973年 | 31441篇 |
1972年 | 28938篇 |
1971年 | 27170篇 |
1970年 | 25043篇 |
1969年 | 23257篇 |
1968年 | 21754篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Rebecca Robillard Karianne Dion Marie‐Helene Pennestri Elizaveta Solomonova Elliott Lee Mysa Saad Anthony Murkar Roger Godbout Jodi D. Edwards Lena Quilty Alexander R. Daros Raj Bhatla Tetyana Kendzerska 《Journal of sleep research》2021,30(1):e13231
This study aimed to evaluate changes in sleep during the COVID‐19 outbreak, and used data‐driven approaches to identify distinct profiles of changes in sleep‐related behaviours. Demographic, behavioural and psychological factors associated with sleep changes were also investigated. An online population survey assessing sleep and mental health was distributed between 3 April and 24 June 2020. Retrospective questions were used to estimate temporal changes from before to during the outbreak. In 5,525 Canadian respondents (67.1% females, 16–95 years old: Mean ± SD = 55.6 ± 16.3 years), wake‐up times were significantly delayed relative to pre‐outbreak estimates (p < .001, = 0.04). Occurrences of clinically meaningful sleep difficulties significantly increased from 36.0% before the outbreak to 50.5% during the outbreak (all p < .001, g ≥ 0.27). Three subgroups with distinct profiles of changes in sleep behaviours were identified: “Reduced Time in Bed”, “Delayed Sleep” and “Extended Time in Bed”. The “Reduced Time in Bed” and “Delayed Sleep” subgroups had more adverse sleep outcomes and psychological changes during the outbreak. The emergence of new sleep difficulties was independently associated with female sex, chronic illnesses, being employed, family responsibilities, earlier wake‐up times, higher stress levels, as well as heavier alcohol use and television exposure. The heterogeneity of sleep changes in response to the pandemic highlights the need for tailored interventions to address sleep problems. 相似文献
22.
23.
24.
D. Gareth Evans Kelly-Anne Phillips Roger L. Milne Robert Fruscio Cezary Cybulski Jacek Gronwald Jan Lubinski Tomasz Huzarski Zerin Hyder Claire Forde Kelly Metcalfe Leigha Senter Jeffrey Weitzel Nadine Tung Dana Zakalik Maria Ekholm Ping Sun Steven A. Narod kConFab Investigators Polish Hereditary
Breast Cancer Consortium Hereditary Breast Cancer Clinical Study Group 《British journal of cancer》2021,124(9):1524
Background The impact of various breast-cancer treatments on patients with a BRCA2 mutation has not been studied. We sought to estimate the impact of bilateral oophorectomy and other treatments on breast cancer-specific survival among patients with a germline BRCA2 mutation.Methods We identified 664 women with stage I–III breast cancer and a BRCA2 mutation by combining five different datasets (retrospective and prospective). Subjects were followed for 7.2 years from diagnosis to death from breast cancer. Tumour characteristics and cancer treatments were patient-reported and derived from medical records. Predictors of survival were determined using Cox proportional hazard models, adjusted for other treatments and for prognostic features.Results The 10-year breast-cancer survival for ER-positive patients was 78.9% and for ER-negative patients was 82.3% (adjusted HR = 1.23 (95% CI, 0.62–2.45, p = 0.55)). The 10-year breast-cancer survival for women who had a bilateral oophorectomy was 89.1% and for women who did not have an oophorectomy was 59.0% (adjusted HR = 0.45; 95% CI, 0.28–0.72, p = 0.001). The adjusted hazard ratio for chemotherapy was 0.83 (95% CI, 0.65–1.53: p = 0.56).Conclusions For women with breast cancer and a germline BRCA2 mutation, positive ER status does not predict superior survival. Oophorectomy is associated with a reduced risk of death from breast cancer and should be considered in the treatment plan.Subject terms: Targeted therapies, Breast cancer 相似文献
25.
Roberto L. Cazzato Pierre De Marini Ian Leonard-Lorant Danoob Dalili Guillaume Koch Pierre A. Autrusseau Theo Mayer Julia Weiss Pierre Auloge Julien Garnon Afshin Gangi 《Diagnostic and interventional imaging》2021,102(6):355-361
PurposeTo retrospectively report on safety, pain relief and local tumor control achieved with percutaneous ablation of sacral bone metastases.Materials and methodsFrom February 2009 to June 2020, 23 consecutive patients (12 women and 11 men; mean age, 60 ± 8 [SD] years; median, 60; range: 48-80 years) with 23 sacral metastases underwent radiofrequency (RFA) or cryo-ablation (CA), with palliative or curative intent at our institution. Patients’ demographics and data pertaining to treated metastases, procedure-related variables, safety, and clinical evolution following ablation were collected and analyzed. Pain was assessed with numerical pain rating scale (NPRS).ResultsSixteen (70%) patients were treated with palliative and 7 (30%) with curative intent. Mean tumor diameter was 38 ± 19 (SD) mm (median, 36; range: 11-76). External radiation therapy had been performed on five metastases (5/23; 22%) prior to ablation. RFA was used in 9 (39%) metastases and CA in the remaining 14 (61%). Thermo-protective measures and adjuvant bone consolidation were used whilst treating 20 (87%) and 8 (35%) metastases, respectively. Five (22%) minor complications were recorded. At mean 31 ± 21 (SD) (median, 32; range: 2-70) months follow-up mean NPRS was 2 ± 2 (SD) (median, 1; range: 0–6) vs. 5 ± 1 (median, 5; range: 4–8; P < 0.001) at the baseline. Three metastases out of 7 (43%) undergoing curative ablation showed local progression at mean 4 ± 4 (SD) (median, 2; range: 1-8) months follow-up.ConclusionPercutaneous ablation of sacral metastases is safe and results in significant long-lasting pain relief. Local tumor control seems sub-optimal; however, further investigations are needed to confirm these findings due to paucity of data. 相似文献
26.
Daniel J. Snyder Thomas R. Kroshus Aakash Keswani Evan B. Garden Karl M. Koenig Kevin J. Bozic David S. Jevsevar Jashvant Poeran Calin S. Moucha 《The Journal of arthroplasty》2019,34(4):613-618
Background
Nursing Home Compare (NHC) ratings, created and maintained by Medicare, are used by both hospitals and consumers to aid in the skilled nursing facility (SNF) selection process. To date, no studies have linked NHC ratings to actual episode-based outcomes. The purpose of this study was to evaluate whether NHC ratings are valid predictors of 90-day complications, readmission, and bundle costs for patients discharged to an SNF after primary total joint arthroplasty (TJA).Methods
All SNF-discharged primary TJA cases in 2017 at a multihospital academic health system were queried. Demographic, psychosocial, and clinical variables were manually extracted from the health record. Medicare NHC ratings were then collected for each SNF. For patients in the Medicare bundle, postacute and total bundle cost was extracted from claims.Results
Four hundred eighty-eight patients were discharged to a total of 105 unique SNFs. In multivariate analysis, overall NHC rating was not predictive of 90-day readmission/major complications, >75th percentile postacute cost, or 90-day bundle cost exceeding the target price. SNF health inspection and quality measure ratings were also not predictive of 90-day readmission/major complications or bundle performance. A higher SNF staffing rating was independently associated with a decreased odds for >75th percentile 90-day postacute spend (odds ratio, 0.58; P = .01) and a 90-day bundle cost exceeding the target price (odds ratio = 0.69; P = .02) but was similarly not predictive of 90-day readmission/complications.Conclusion
Results of our study suggest that Medicare's NHC tool is not a useful predictor of 90-day costs, complications, or readmissions for SNFs within our health system. 相似文献27.
Background
Highly cross-linked polyethylene (HXLPE) liners in total hip arthroplasty (THA) have demonstrated decreased wear rates, resilience to cup orientation, and reduced osteolysis compared to conventional polyethylene. Sequential irradiation and annealing below the melting temperature is unique compared to most HXLPE which is irradiated and remelted. This study purpose is to provide minimum 5-year femoral head penetration rates of sequentially annealed HXLPE in primary THA.Methods
A retrospective review of a prospectively collected database identified 198 consecutive, cementless primary THAs utilizing sequentially annealed HXLPE (X3; Stryker, Mahwah, NJ). Operative technique was standardized. Radiographs were analyzed utilizing the Martell method with minimum 5-year and 1-year radiographs as baseline to minimize the initial bedding-in period.Results
Seventy-seven hips with minimum 5-year follow-up were analyzed. Mean steady state linear and volumetric head penetration rates were 0.095 mm/y and 76 mm3/y, respectively. Volumetric head penetration was significantly less for 32-mm compared to 36-mm (P = .028). In addition, less head penetration was observed for ceramic 32-mm heads at nearly half the rate compared to cobalt-chromium 36-mm heads (P ≥ .092). No correlations existed between penetration rates and age, body mass index, University of California Los Angeles Activity Level, polyethylene thickness, cup inclination, or anteversion (P ≥ .10). No radiographic osteolysis was observed.Conclusion
Surprisingly, linear head penetration rates of sequentially annealed HXLPE were nearly identical to the osteolysis threshold for conventional polyethylene and greater than reports of irradiated and remelted HXLPE. Furthermore, these data corroborate reports that HXLPE is resilient to cup orientation and demographic variables. Longer term follow-up is recommended. 相似文献28.
29.
Kyle E. Embertson Diann M. Krywko Eric R. Bunch 《The American journal of emergency medicine》2019,37(5):1005.e3-1005.e4
Nephrolithiasis is a common pathology encountered in the primary care and emergency department (ED) setting. In 2009 alone, there were over one million ED visits related to nephrolithiasis Higa et al. (2017) [1]. Emergent treatment options range from non-invasive pain control and patient education to lithotripsy and other invasive urologic procedures depending on stone location and related pathology. Urethral calculi are estimated to represent 0.3% of all urinary stone diseases Verit et al. (2006) [2]. There are very few case reports documenting distal urethral stone removal in the ED. Here we present a case of distal urethral stone impaction and the removal of this stone by ED providers, leading to expedited care and prevention of consultation and possible admission. 相似文献
30.
Umesh Wadgave Mahesh R. Khairnar Tanvi S. Kadu Yogesh Wadgave 《Acta odontologica Scandinavica》2019,77(3):181-183
Introduction: Significance testing for comparison of the baseline differences between the intervention arms has received a strong condemnation. The goal of this study was to assess the prevalence of randomized controlled trials (RCTs) comparing the baseline characteristics between intervention groups using significance tests in top ten impact factor dental journals.Materials and methods: RCTs published in 10 high impact factor dental journals were searched in PubMed database. Literature search was limited to time duration of 5 years from September 2012 to August 2017.Results: We analysed 521 RCTs after excluding 47 non-RCT articles from the total of 568 articles. Baseline demographic characteristics table was not reported in 45.9% of the RCTs and 26.2% of the RCTs did not report table of baseline clinical characteristics. In 38.9% of the studies, significance testing was employed to compare baseline differences between the intervention arms.Conclusions: Many trials published in the reputed dental journals failed to follow the recommendations of CONSORT statement regarding reporting of baseline tables and avoiding comparison of baseline differences with significance test. 相似文献