全文获取类型
| 收费全文 | 1333772篇 |
| 免费 | 89099篇 |
| 国内免费 | 3878篇 |
专业分类
| 耳鼻咽喉 | 19041篇 |
| 儿科学 | 40808篇 |
| 妇产科学 | 36208篇 |
| 基础医学 | 190150篇 |
| 口腔科学 | 37702篇 |
| 临床医学 | 116903篇 |
| 内科学 | 255934篇 |
| 皮肤病学 | 30324篇 |
| 神经病学 | 100529篇 |
| 特种医学 | 51654篇 |
| 外国民族医学 | 284篇 |
| 外科学 | 202353篇 |
| 综合类 | 29716篇 |
| 现状与发展 | 2篇 |
| 一般理论 | 318篇 |
| 预防医学 | 87359篇 |
| 眼科学 | 31841篇 |
| 药学 | 107188篇 |
| 31篇 | |
| 中国医学 | 4497篇 |
| 肿瘤学 | 83907篇 |
出版年
| 2021年 | 9917篇 |
| 2019年 | 9970篇 |
| 2018年 | 14747篇 |
| 2017年 | 11498篇 |
| 2016年 | 12757篇 |
| 2015年 | 14320篇 |
| 2014年 | 19551篇 |
| 2013年 | 27846篇 |
| 2012年 | 38085篇 |
| 2011年 | 40010篇 |
| 2010年 | 23653篇 |
| 2009年 | 22212篇 |
| 2008年 | 36879篇 |
| 2007年 | 39671篇 |
| 2006年 | 40070篇 |
| 2005年 | 37745篇 |
| 2004年 | 35920篇 |
| 2003年 | 34488篇 |
| 2002年 | 33217篇 |
| 2001年 | 76941篇 |
| 2000年 | 78932篇 |
| 1999年 | 65449篇 |
| 1998年 | 16155篇 |
| 1997年 | 14024篇 |
| 1996年 | 13600篇 |
| 1995年 | 12709篇 |
| 1994年 | 11448篇 |
| 1993年 | 10802篇 |
| 1992年 | 47943篇 |
| 1991年 | 45597篇 |
| 1990年 | 44667篇 |
| 1989年 | 42998篇 |
| 1988年 | 38928篇 |
| 1987年 | 37761篇 |
| 1986年 | 35473篇 |
| 1985年 | 33144篇 |
| 1984年 | 23768篇 |
| 1983年 | 19864篇 |
| 1982年 | 10801篇 |
| 1979年 | 20877篇 |
| 1978年 | 13835篇 |
| 1977年 | 12387篇 |
| 1976年 | 10519篇 |
| 1975年 | 12048篇 |
| 1974年 | 13971篇 |
| 1973年 | 13476篇 |
| 1972年 | 12855篇 |
| 1971年 | 12188篇 |
| 1970年 | 11141篇 |
| 1969年 | 10784篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
11.
T. Maishman H. Sheikh P. Boger J. Kelly K. Cozens A. Bateman S. Davies M. Fay D. Sharland A. Jackson 《Clinical oncology (Royal College of Radiologists (Great Britain))》2021,33(5):e225-e231
AimsSelf-expanding metal stents provide rapid improvement of dysphagia in oesophageal cancer but are associated with complications. The aim of the present study was to test the effectiveness of an alternative treatment of combining biodegradable stents with radiotherapy.Materials and methodsA Simon two-stage single-arm prospective phase II trial design was used to determine the efficacy of biodegradable stents plus radiotherapy in patients with dysphagia caused by oesophagus cancer who were unsuitable for radical treatment. Fourteen patients were recruited and data from 12 were included in the final analyses.ResultsFive of 12 patients met the primary end point: one stent-related patient death; four further interventions for dysphagia within 16 weeks of stenting (41.7%, 95% confidence interval 15.2–72.3%). The median time to a 10-point deterioration of quality of life was 2.7 weeks. Nine patients died within 52 weeks of registration. The median time to death from any cause was 15.0 weeks (95% confidence interval 9.6–not reached).ConclusionThe high re-intervention observed, which met the pre-defined early stopping criteria, meant that the suggested alternative treatment was not sufficiently effective to be considered for a larger scale trial design. Further work is needed to define the place of biodegradable stents in the management of malignant oesophageal strictures. 相似文献
12.
<正>Norepinephrine (NE; also known as noradrenaline) is the body's primary adrenergic neurotransmitter which belongs to the catecholamine family. Norepinephrine has pharmacologic effects on theα1 (Suita et al.,2015),α2 (Schwartz,1997),β1,β2 andβ3(Tsukada et al., 2003) adrenoceptors. In the brain, norepinephrine increases arousal and alertness, promotes vigilance, enhances formation and retrieval of memory, and focuses attention. It also increases restlessness and anxiety. In the remainder of the body, 相似文献
13.
Polly Yeung Joanne Allen Hazel K. Godfrey Fiona Alpass Christine Stephens 《Aging & mental health》2019,23(8):992-999
Objectives: To compare indicators relating to aging and health among veterans and non-veterans, and identify factors associated with subjective wellbeing (SWB) of older New Zealand veterans.
Methods: Self-reported data were obtained from participants in a longitudinal cohort study of New Zealand older adults. Responses from 352 veterans and 1500 non-veterans (age range of 55–86 and gender matched) were selected as a comparison group on indicators related to health and aging. The association of these indicators with veterans’ SWB were assessed using hierarchical regression.
Results: Apart from being older, smoking more, and having more chronic conditions, veterans did not differ from non-veterans on indicators of health and wellbeing. Mental health, physical health, purpose in life, housing satisfaction, and capabilities (choice and freedom) accounted for a significant amount of variance in veterans’ SWB.
Conclusion: Our results suggest that older veterans do not differ greatly on indices of health and aging from their non-veteran peers. Results support previous findings that lower mental and physical health is associated with lower SWB for veterans. Building upon prior findings, the current results demonstrate that interventions focusing on enhancing a sense of purpose in life, supporting one's capability to achieve, and strengthening social and physical environment through social connectedness, may serve as protective factors for SWB in veterans. 相似文献
14.
B. Kowall N. Lehmann A.A. Mahabadi S. Moebus R. Erbel K.H. Jöckel A. Stang 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2019,29(3):228-235
Background and aims
There is controversy on the potentially benign nature of metabolically healthy obesity (MHO), i.e., obese persons with few or no metabolic abnormalities. So far, associations between MHO and coronary artery calcification (CAC), a measure of subclinical atherosclerosis, have mainly been studied cross-sectionally in Asian populations. We assessed cross-sectional and longitudinal MHO CAC associations in a Caucasian population.Methods and results
In the Heinz Nixdorf Recall Study, a population-based cohort study in Germany, CAC was assessed by electron-beam tomography at baseline and at 5-year follow-up. For cross-sectional and longitudinal analyses, we included 1585 participants free of coronary heart disease at baseline, with CAC measurements at baseline and at follow-up, and with either normal weight (BMI 18.5–24.9 kg/m2) or obesity (BMI ≥30.0 kg/m2) at baseline. We used four definitions of MHO. In our main analysis, we defined obese persons as metabolically healthy if they met ≤1 of the NCEP ATP III criteria for the definition of the metabolic syndrome – waist circumference was not taken into account because of collinearity with BMI.Persons with MHO had a higher prevalence of CAC than metabolically healthy normal weight (MHNW) persons (prevalence ratio = 1.59 (95% confidence interval 1.38–1.84) for the main analysis). Persons with MHO had slightly larger odds of CAC progression than persons with MHNW (odds ratios ranged from 1.17 (0.69–1.99) to 1.48 (1.02–2.13) depending on MHO definition and statistical approach).Conclusion
Our analyses on MHO CAC associations add to the evidence that MHO is not a purely benign health condition. 相似文献15.
16.
Evangelia Liouta Vasileios K Katsaros George Stranjalis Edyta Leks Uwe Klose Sotirios Bisdas 《Journal of neuroradiology. Journal de neuroradiologie》2019,46(3):199-206
Background and purpose
Evidence of pre-operative resting state functional magnetic resonance (RS-fMRI) validation by correlating it with clinical pre-operative status in brain tumor patients is scarce. Our aim was to validate the functional relevance of RS-fMRI by investigating the association between RS-fMRI and pre-operative motor and language function performance in patients with brain tumor.Materials and methods
Sixty-nine patients with brain tumors were prospectively recruited. Patients with tumors near precentral gyrus (n?=?49) underwent assessment for apparent (paresis) and subtle (finger tapping) deficits. Patients with left frontal tumors in the vicinity of the inferior frontal gyrus (n?=?29) underwent assessment for gross (aphasia) and mild language (phonological verbal fluency) deficits. RS-fMRI results were extracted by spatial independent component analysis (ICA).Results
Motor group: paretic patients showed significantly (P?=?0.01) decreased BOLD signal in ipsilesional precentral gyrus when compared to contralesional one. Significantly (P?<?0.01) lower BOLD signal was also observed in ipsilesional precentral gyrus of paretics when compared with the non-paretics. In asymptomatic patients, a strong positive correlation (r?=?0.68, P?<?0.01) between ipsilesional motor cortex BOLD signal and contralesional finger tapping performance was observed. Language group: patients with aphasia showed significantly (P?=?0.01) decreased RS-fMRI BOLD signal in left BA 44 when compared with non- aphasics. In asymptomatic patients, a strong positive correlation (r?=?0.72, P?<?0.01) between BA 44 BOLD signal and phonological fluency performance was observed.Conclusions
Our results showed that RS-fMRI BOLD signal of motor and language networks were significantly affected by the tumors implying the usefulness of the method for assessment of the underlying functions in brain tumors patients. 相似文献17.
Chancellor F. Gray Hernan A. Prieto Justin T. Deen Hari K. Parvataneni 《The Journal of arthroplasty》2019,34(2):206-210
Background
Revision total joint arthroplasty (TJA) is associated with increased readmissions, complications, and expense compared to primary TJA. Bundled payment methods have been used to improve value of care in primary TJA, but little is known of their impact in revision TJA patients. The purpose of this study is to evaluate the impact of a care redesign for a bundled payment model for primary TJA on quality metrics for revision patients, despite absence of a targeted intervention for revisions.Methods
We compared quality metrics for all revision TJA patients including readmission rate, use of post–acute care facility after discharge, length of stay, and cost, between the year leading up to the redesign and the 2 years following its implementation. Changes in the primary TJA group over the same time period were also assessed for comparison.Results
Despite a volume increase of 37% over the study period, readmissions declined from 8.9% to 5.8%. Use of post–acute care facilities decreased from 42% to 24%. Length of stay went from 4.84 to 3.92 days. Cost of the hospital episode declined by 5%.Conclusion
Our health system experienced a halo effect from our bundled payment-influenced care redesign, with revision TJA patients experiencing notable improvements in several quality metrics, though not as pronounced as in the primary TJA population. These changes benefitted the patients, the health system, and the payers. We attribute these positive changes to an altered institutional mindset, resulting from an invested and aligned care team, with active physician oversight over the care episode. 相似文献18.
19.
David C. Johnson Steven S. Raman Sohrab A. Mirak Lorna Kwan Amirhossein M. Bajgiran William Hsu Cleo K. Maehara Preeti Ahuja Izak Faiena Aydin Pooli Amirali Salmasi Anthony Sisk Ely R. Felker David S.K. Lu Robert E. Reiter 《European urology》2019,75(5):712-720
Background
Multiparametric magnetic resonance imaging (mpMRI) undoubtedly affects the diagnosis and treatment of localized prostate cancer (CaP). However, clinicians need a better understanding of its accuracy and limitations in detecting individual CaP foci to optimize management.Objective
To determine the per-lesion detection rate for CaP foci by mpMRI and identify predictors of tumor detection.Design, setting, and participants
We carried out a retrospective analysis of a prospectively managed database correlating lesion-specific results from mpMRI co-registered with whole-mount pathology (WMP) prostatectomy specimens from June 2010 to February 2018. Participants include 588 consecutive patients with biopsy-proven CaP undergoing 3-T mpMRI before radical prostatectomy at a single tertiary institution.Outcome measurements and statistical analysis
We measured mpMRI sensitivity in detecting individual CaP and clinically significant (any Gleason score ≥7) CaP foci and predictors of tumor detection using multivariate analysis.Results and limitations
The final analysis included 1213 pathologically confirmed tumor foci in 588 patients with primarily intermediate- (75%) or high-risk (12%) CaP. mpMRI detected 45% of all lesions (95% confidence interval [CI] 42–47%), including 65% of clinically significant lesions (95% CI 61–69%) and nearly 80% of high-grade tumors. Some 74% and 31% of missed solitary and multifocal tumors, respectively, were clinically significant. The majority of missed lesions were small (61.1% ≤1 cm); 28.3% were between 1 and 2 cm, and 10.4% were >2 cm. mpMRI missed at least one clinically significant focus in 34% of patients overall, and in 45% of men with multifocal lesions. On multivariate analysis, smaller, low-grade, multifocal, nonindex tumors with lower prostate-specific antigen density were more likely to be missed. Limitations include selection bias in a prostatectomy cohort, lack of specificity data, an imperfect co-registration process, and uncertain clinical significance for undetected lesions.Conclusions
mpMRI detects less than half of all and less than two-thirds of clinically significant CaP foci. The moderate per-lesion sensitivity and significant proportion of men with undetected tumor foci demonstrate the current limitations of mpMRI.Patient summary
Magnetic resonance imaging of the prostate before surgical removal for prostate cancer finds less than half of all individual prostate cancer tumors. Large, solitary, aggressive tumors are more likely to be visualized on imaging. 相似文献20.
Anthony J. Bleyer Vincent A. Scavo Samuel E. Wilson Barry J. Browne Brian L. Ferris C. Keith Ozaki Timmy Lee Eric K. Peden Bradley S. Dixon Rick Mishler Timothy P. O&#x;Connor Kendrah Kidd Steven K. Burke 《Journal of vascular surgery》2019,69(2):507-515