全文获取类型
| 收费全文 | 3632112篇 |
| 免费 | 247579篇 |
| 国内免费 | 9329篇 |
专业分类
| 耳鼻咽喉 | 49042篇 |
| 儿科学 | 120025篇 |
| 妇产科学 | 99378篇 |
| 基础医学 | 508640篇 |
| 口腔科学 | 102291篇 |
| 临床医学 | 331945篇 |
| 内科学 | 706776篇 |
| 皮肤病学 | 85437篇 |
| 神经病学 | 293514篇 |
| 特种医学 | 137293篇 |
| 外国民族医学 | 941篇 |
| 外科学 | 540633篇 |
| 综合类 | 77828篇 |
| 现状与发展 | 8篇 |
| 一般理论 | 1393篇 |
| 预防医学 | 277299篇 |
| 眼科学 | 84046篇 |
| 药学 | 264514篇 |
| 96篇 | |
| 中国医学 | 7996篇 |
| 肿瘤学 | 199925篇 |
出版年
| 2021年 | 28497篇 |
| 2019年 | 29697篇 |
| 2018年 | 40991篇 |
| 2017年 | 31139篇 |
| 2016年 | 35454篇 |
| 2015年 | 40168篇 |
| 2014年 | 55584篇 |
| 2013年 | 83031篇 |
| 2012年 | 111917篇 |
| 2011年 | 118464篇 |
| 2010年 | 70943篇 |
| 2009年 | 67351篇 |
| 2008年 | 110320篇 |
| 2007年 | 117436篇 |
| 2006年 | 119062篇 |
| 2005年 | 114208篇 |
| 2004年 | 109893篇 |
| 2003年 | 105687篇 |
| 2002年 | 102080篇 |
| 2001年 | 175751篇 |
| 2000年 | 179891篇 |
| 1999年 | 151296篇 |
| 1998年 | 42995篇 |
| 1997年 | 37871篇 |
| 1996年 | 37997篇 |
| 1995年 | 36846篇 |
| 1994年 | 33682篇 |
| 1993年 | 31564篇 |
| 1992年 | 117098篇 |
| 1991年 | 112941篇 |
| 1990年 | 109323篇 |
| 1989年 | 105610篇 |
| 1988年 | 96572篇 |
| 1987年 | 94590篇 |
| 1986年 | 88807篇 |
| 1985年 | 84786篇 |
| 1984年 | 63210篇 |
| 1983年 | 53637篇 |
| 1982年 | 31461篇 |
| 1979年 | 55915篇 |
| 1978年 | 39253篇 |
| 1977年 | 33403篇 |
| 1976年 | 31144篇 |
| 1975年 | 32957篇 |
| 1974年 | 39317篇 |
| 1973年 | 37579篇 |
| 1972年 | 35095篇 |
| 1971年 | 32576篇 |
| 1970年 | 30103篇 |
| 1969年 | 28772篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
11.
D. Medenwald A. Kluttig M.E. Lacruz J. Schumann 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2019,29(2):152-158
Background and Aims
Diet is known to play a decisive role in the development of coronary heart disease (CHD). One factor believed to decrease lifetime risk of CHD is the consumption of omega-3 fatty acids. Yet, conclusive evidence regarding the potential cardioprotective effects of fatty acids is far from being reached. The present study aimed to provide further evidence on the association of serum fatty acid profiles with CHD risk.Methods and Results
The CARdio-vascular Disease, Living and Ageing in Halle study (CARLA study) is an observational cohort study comprising an older adult's general population with a high level of cardiovascular risk factors. In a matched case–control design the serum fatty acid concentrations of 73 subjects with an incident fatal or nonfatal CHD event were compared to 146 controls matched for sex and age. Our data show that the participants of the CARLA study are underserved in unsaturated fatty acids with respect to current dietary recommendations. In addition, the ratio of omega-6 to omega-3 fatty acids was determined to be 8:1 which underlines the consumption of a Western-style diet enriched in omega-6 fatty acids. There were no significant differences in fatty acid patterns between cases and controls. Thus, no clear association of particular serum fatty acid levels with cardiovascular risk was found.Conclusion
Our results support the conclusion that in populations with a homogenous low level of omega-3 polyunsaturated fatty acids consumption, serum fatty acid levels are not associated with CHD risk. 相似文献12.
Jennifer M. Sasaki Russell Gregory A. Chinn Deenu Maharjan Yasmine Eichbaum Jeffrey W. Sall 《British journal of anaesthesia》2019,122(4):490-499
Background
The factors determining peak susceptibility of the developing brain to anaesthetics are unclear. It is unknown why postnatal day 7 (P7) male rats are more vulnerable to anaesthesia-induced memory deficits than littermate females. Given the precocious development of certain regions in the female brain during the neonatal critical period, we hypothesised that females are susceptible to anaesthetic brain injury at an earlier time point than previously tested.Methods
Female rats were exposed to isoflurane (Iso) 1 minimum alveolar concentration or sham anaesthesia at P4 or P7. Starting at P35, rats underwent a series of behavioural tasks to test their spatial and recognition memory. Cell death immediately after anaesthesia was quantified by Fluoro-Jade C staining in select brain regions, and developmental expression of the chloride transporters KCC2 and NKCC1 was analysed by immunoblotting in male and female rats at P4 and P7.Results
Female rats exposed to Iso at P4 displayed impaired spatial, object-place, -context, and social recognition memory, and increased cell death in the hippocampus and laterodorsal thalamus. Female rats exposed at P7 exhibited only decreased performance in object-context compared with control. The ratio of NKCC1/KCC2 expression in cerebral cortex was higher in P4 females than in P7 females, and similar to that in P7 males.Conclusions
Female rats exposed to Iso at P4 are sensitive to anaesthetic injury historically observed in P7 males. This is consistent with a comparably immature developmental state in P4 females and P7 males. The window of anaesthetic vulnerability correlates with sex-specific cortical expression of chloride transporters NKCC1 and KCC2. These findings suggest that both sex and developmental age play important roles in determining the outcome after early anaesthesia exposure. 相似文献13.
Background
Total knee arthroplasty is a treatment option for debilitating arthritis. In the postoperative period, patients experience moderate to severe pain affecting the rehabilitation, hospital stay, and patient satisfaction. This study aims at utilizing current best evidence to determine whether adductor canal block (ACB) or periarticular injection (PAI) is a better modality for managing short-term postoperative pain and opioid consumption.Methods
Embase, MEDLINE, HealthStar, Emcare, and PubMed were searched for randomized controlled trials from 1946 to August 2018, for literature addressing the comparison of ACB and PAI for pain management in the setting of total knee arthroplasty. A systematic review and meta-analysis were performed.Results
Six studies were included in our meta-analysis. When examining the combined visual analog scale (VAS) pain values for each group, analysis demonstrated greater reduction in scores for the PAI group, and the difference was statistically significant (P = .001). When comparing the VAS scores of subgroups analyzed at specific periods in time, there was a trend toward lower VAS scores in subgroups analyzed at 24 hours and 48 hours postoperatively (at rest and at movement) in the PAI group. Overall opioid consumption was lower in the PAI group, with demonstrated statistical significance (P = .03). When comparing the postoperative subgroups, there was a trend toward decreased opioid use in the PAI group, with 13.25% less opioid use at 48 hours and 9.5% less opioid use at 24 hours.Conclusion
PAI could significantly improve postoperative pain and opioid consumption when compared with ACB. Additional, high-quality studies are required to further address this topic. 相似文献14.
Conall T. Morgan Brigitte Mueller Varsha Thakur Vitor Guerra Callaghan Jull Luc Mertens Mark Friedberg Fraser Golding Mike Seed Steven E.S. Miner Edgar T. Jaeggi Cedric Manlhiot Lynne E. Nield 《The Canadian journal of cardiology》2019,35(4):453-461
Background
The purpose of the study was to evaluate the association between fetal echocardiographic measurements and the need for intervention (primary coarctation repair, staged coarctation repair, or catheter intervention) in prenatally diagnosed coarctation of the aorta.Methods
A single-centre retrospective cohort study (2005-2015) of 107 fetuses diagnosed with suspected coarctation of the aorta in the setting of an apex-forming left ventricle and antegrade flow across the mitral and aortic valves.Results
Median gestational age at diagnosis was 32 weeks (interquartile range, 23-35 weeks). Fifty-six (52%) did not require any neonatal intervention, 51 patients (48%) underwent a biventricular repair. In univariable analysis, an increase in ascending aorta (AAo) peak Doppler flow velocity (odds ratio [OR], 1.40 [95% confidence interval [CI], 1.05-1.91] per 20 cm/s; P = 0.03) was associated with intervention. No intervention was associated with larger isthmus size (OR, 0.23; P < 0.001), transverse arch diameter (OR, 0.23; P < 0.001), and aortic (OR, 0.72; P = 0.02), mitral (OR, 0.58; P = 0.001), and AAo (OR, 0.53; P < 0.001) z-scores. In multivariable analysis, higher peak AAo Doppler (OR, 2.51 [95% CI, 1.54-4.58] per 20 cm/s; P = 0.001) and younger gestational age at diagnosis (OR, 0.81 [95% CI, 0.70-0.93] per week; P = 0.005) were associated with intervention, whereas a higher AAo z-score (OR, 0.65 [95% CI, 0.43-0.94] per z; P = 0.029) and transverse arch dimension (OR, 0.44 [95% CI, 0.18-0.97]; P = 0.05) decreased the risk of intervention.Conclusions
In prenatally suspected coarctation, the variables associated with intervention comprised smaller AAo and transverse arch size, earlier gestational age at diagnosis, and the additional finding of a higher peak AAo Doppler. 相似文献15.
Daniel S. Tsze Sharon S. Pan Kerrin C. DePeter Anju M. Wagh Stephen L. Gordon Peter S. Dayan 《The American journal of emergency medicine》2019,37(6):1128-1132
ObjectivesWe aimed to describe the analgesic efficacy, duration of analgesia, and adverse event profile associated with intranasal hydromorphone in children with acute pain presenting to an emergency department.MethodsProspective dose titration pilot study of otherwise healthy children 4 to 17-years-old with moderate to severe pain who required a parenteral opioid. All patients received an initial intranasal hydromorophone dose of 0.03 mg/kg. The need for additional analgesia was assessed at 15 and 30 min; an additional 0.015 mg/kg was given at each assessment, if required. Need for rescue analgesic, pain intensity and adverse events were assessed until 6 h after hydromorphone administration or until patients were discharged, underwent a procedure to treat their painful condition, or received a rescue analgesic.ResultsWe enrolled 35 children. Fifteen, 11, and 9 children required a total dose of 0.03, 0.045, and 0.06 mg/kg, respectively. Patients in each dose group experienced an absolute decrease in pain score of ≥3/10 and percent reduction >40% within 5–15 min of completing dose-titration administration of hydromorphone. Duration of analgesia (i.e. time until rescue analgesic administered) >1 h was observed in 85.7% of patients. Patients not requiring rescue analgesics had mild or no pain until discharged or their painful conditions were treated. Three (8.6%) patients required a rescue analgesic <1 h after hydromorphone administration. There were no major adverse events.ConclusionsIntranasal hydromorphone led to rapid, clinically significant and frequently sustained decreases in pain intensity in children. No major adverse events were observed in this preliminary sample.Clinical Trials Registration Number: NCT02437669 相似文献
16.
Eytan M. Debbi Benjamin Bernfeld Amir Herman Moshe Salai Yocheved Laufer Alon Wolf 《The Journal of arthroplasty》2019,34(1):47-55
Background
Biomechanics after total knee arthroplasty (TKA) often remain abnormal and may lead to prolonged postoperative recovery. The purpose of this study is to assess a biomechanical therapy after TKA.Methods
This is a randomized controlled trial of 50 patients after unilateral TKA. One group underwent a biomechanical therapy in which participants followed a walking protocol while wearing a foot-worn biomechanical device that modifies knee biomechanics and the control group followed a similar walking protocol while wearing a foot-worn sham device. All patients had standard physical therapy postoperatively as well. Patients were evaluated throughout the first postoperative year with clinical measures and gait analysis.Results
Improved outcomes were seen in the biomechanical therapy group compared to the control group in pain scores (88% vs 38%, P = .011), function (86% vs 21%, P = .001), knee scores (83% vs 38%, P = .001), and walking distance (109% vs 47%, P = .001) at 1 year. The therapy group showed healthier biomechanical gait patterns in both the sagittal and coronal planes at 1 year.Conclusion
A postoperative biomechanical therapy improves outcomes following TKA and should be considered as an additional therapy postoperatively. 相似文献17.
Sophia A. Traven Russell A. Reeves Molly G. Sekar Harris S. Slone Zeke J. Walton 《The Journal of arthroplasty》2019,34(1):140-144
Background
While the 11-factor modified frailty index (mFI) has been shown to predict adverse outcomes in patients undergoing total joint arthroplasty, the 5-factor index has not been evaluated in this patient population. The goal of this study was to evaluate the utility of the mFI-5 as a predictor of morbidity and mortality in patients undergoing primary total hip and knee arthroplasty.Methods
A retrospective analysis of the American College of Surgeons National Surgical Quality Improvement Program's database for patients undergoing total hip arthroplasty and total knee arthroplasty between the years 2005 and 2016 was conducted. The 5-factor score, which includes the presence of comorbid diabetes, hypertension, congestive heart failure, chronic obstructive pulmonary disease, and functional status, was calculated for each patient. Multivariate logistic regression models were used to assess the relationship between the mFI-5 and postoperative complications while controlling for demographic variables.Results
One hundred forty thousand one hundred fifty-eight patients undergoing total hip arthroplasty and 226,398 patients undergoing total knee arthroplasty were identified. After adjusting for demographic variables and comorbid conditions, logistic regression analyses revealed that the mFI-5 was a strong predictor for total complications, Clavien-Dindo grade IV complications (cardiac arrest, myocardial infarction, septic shock, pulmonary embolism, postoperative dialysis, reintubation, and prolonged ventilator requirement), surgical site infections, readmission, and 30-day mortality (P < .001).Conclusions
The mFI-5 is an independent predictor of postoperative complications including life-threatening medical complications, surgical site infections, hospital readmission, and 30-day mortality after primary hip and knee arthroplasty. This clinical tool can be used to identify high-risk surgical patients and guide preoperative counseling to optimize outcomes.Level of Evidence
III. 相似文献18.
Arne de Niet Michel M.P.J. Reijnen Clark J. Zeebregts 《Journal of vascular surgery》2019,69(2):348-356
Objective
The objective of this study was to investigate the feasibility of a specific custom-made fenestrated aortic cuff in the treatment of complex abdominal aortic aneurysms (AAAs).Methods
Between 2013 and 2016, a total of 57 custom-made Fenestrated Anaconda (Vascutek, Inchinnan, Scotland, UK) aortic cuffs were placed in 38 centers worldwide. All centers were invited to participate in this retrospective analysis. Postoperative and follow-up data included the presence of adverse events, necessity for reintervention, and renal function.Results
Fifteen clinics participated, leading to 29 cases. Median age at operation was 74 years (interquartile range [IQR], 71-78 years); five patients were female. Two patients were treated for a para-anastomotic AAA after open AAA repair, 19 patients were treated because of a complicated course after primary endovascular AAA repair, and 8 cases were primary procedures for AAA. A total of 76 fenestrations (mean, 2.6 per case) were used. Four patients needed seven adjunctive procedures. Two patients underwent conversion, one because of a dissection of the superior mesenteric artery and one because of perforation of a renal artery. Median operation time was 225 minutes (IQR, 150-260 minutes); median blood loss, 200 mL (IQR, 100-500 mL); and median contrast volume, 150 mL (IQR, 92-260 mL). Primary technical success was achieved in 86% and secondary technical success in 93%. The 30-day morbidity was 7 of 29 with a mortality rate of 4 of 29. Estimated glomerular filtration rate remained unchanged before and after surgery (76 to 77 mL/min/m2). Between preoperative and median follow-up of 11 months, estimated glomerular filtration rate was reduced statistically significantly (76 to 63 mL/min/m2). During follow-up, 9 cases had an increase in aneurysm sac diameter (5 cases >5 mm); 14 cases had a stable or decreased aneurysm sac diameter; and in 2 cases, no aneurysm size was reported. No type I endoleak was reported, and two cases with a type III endoleak were treated by endovascular means during follow-up. Survival, reintervention-free survival, and target vessel patency at 1 year were 81% ± 8%, 75% ± 9%, and 99% ± 1%, respectively. After 2 years, these numbers were 81% ± 8%, 67% ± 11%, and 88% ± 6%, respectively. During follow-up, the two patients with a type III endoleak needed endograft-related reinterventions.Conclusions
Treatment with this specific custom-made fenestrated aortic cuff is feasible after complicated previous (endovascular) aortic repair or in complex AAAs. The complexity of certain AAA cases is underlined in this study, and the Fenestrated Anaconda aortic cuff is a valid option in selected cases in which few treatment options are left. 相似文献19.
Javed Butler Mei Yang Massimiliano Alfonzo Manzi Gregory P. Hess Mahesh J. Patel Thomas Rhodes Michael M. Givertz 《Journal of the American College of Cardiology》2019,73(8):935-944
Background
Epidemiology of patients with worsening heart failure and reduced ejection fraction (HFrEF) in the real-world setting is not well described.Objectives
The purpose of this study was to describe incidence, clinical characteristics, treatment, and outcomes of patients with HFrEF who develop worsening heart failure (HF) in the real-world setting.Methods
Data on patients with incident HFrEF from the National Cardiovascular Data Registry PINNACLE were linked to pharmacy, private practitioner, and hospital claims databases. Incidence, clinical characteristics, treatment (angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, beta-blocker, and mineralocorticoid receptor antagonist) and outcomes of patients with worsening HF, defined as ≥90 days of stable HF with subsequent worsening requiring intravenous diuretic agents, were assessed.Results
Of 11,064 HFrEF patients, 1,851 (17%) developed worsening HF on average 1.5 years following initial HF diagnosis. Patients who developed worsening HF were more likely to be African American, be octogenarians, and have higher comorbidity burden (p < 0.001). At the onset of worsening HF, 42.4% of patients were on monotherapy, 43.4% were on dual therapy, and 14.1% were on triple therapy. A total of 48%, 61%, and 98% of patients were on >50% target dose for angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, beta-blocker, and mineralocorticoid receptor antagonist, respectively. The 2-year mortality rate was 22.5%, and 56% of patients were rehospitalized within 30 days of the worsening HF event.Conclusions
In the real-world setting, 1 in 6 patients with HFrEF develop worsening HF within 18 months of HF diagnosis. These patients have a high risk for 2-year mortality and recurrent HF hospitalizations. The use of standard-of-care therapies both before and after the onset of worsening HF is low. With high unmet medical need, patients with worsening HF require novel treatment strategies as well as greater optimization of existing guideline-directed therapy. 相似文献20.
Andrea Garatti Andrea Daprati Marzia Cottini Claudio F. Russo Margherita Dalla Tomba Giovanni Troise Antonio Salsano Francesco Santini Roberto Scrofani Francesca Nicolò Elisa Mikus Alberto Albertini Luca Di Marco Davide Pacini Marco Picichè Loris Salvador Guglielmo M. Actis Dato Paolo Centofanti Lorenzo Menicanti 《The Annals of thoracic surgery》2021,111(4):1242-1251
- Download : Download high-res image (165KB)
- Download : Download full-size image