全文获取类型
| 收费全文 | 2236308篇 |
| 免费 | 168312篇 |
| 国内免费 | 7371篇 |
专业分类
| 耳鼻咽喉 | 29870篇 |
| 儿科学 | 71645篇 |
| 妇产科学 | 60260篇 |
| 基础医学 | 310350篇 |
| 口腔科学 | 62269篇 |
| 临床医学 | 201079篇 |
| 内科学 | 444180篇 |
| 皮肤病学 | 52332篇 |
| 神经病学 | 178380篇 |
| 特种医学 | 90913篇 |
| 外国民族医学 | 472篇 |
| 外科学 | 345609篇 |
| 综合类 | 49601篇 |
| 现状与发展 | 3篇 |
| 一般理论 | 675篇 |
| 预防医学 | 170071篇 |
| 眼科学 | 49195篇 |
| 药学 | 166200篇 |
| 44篇 | |
| 中国医学 | 4573篇 |
| 肿瘤学 | 124270篇 |
出版年
| 2018年 | 22781篇 |
| 2017年 | 17998篇 |
| 2016年 | 21179篇 |
| 2015年 | 23595篇 |
| 2014年 | 32621篇 |
| 2013年 | 48413篇 |
| 2012年 | 62051篇 |
| 2011年 | 66175篇 |
| 2010年 | 40415篇 |
| 2009年 | 38913篇 |
| 2008年 | 61807篇 |
| 2007年 | 65985篇 |
| 2006年 | 67435篇 |
| 2005年 | 64687篇 |
| 2004年 | 61943篇 |
| 2003年 | 60093篇 |
| 2002年 | 57562篇 |
| 2001年 | 112463篇 |
| 2000年 | 115836篇 |
| 1999年 | 96730篇 |
| 1998年 | 26996篇 |
| 1997年 | 24027篇 |
| 1996年 | 24782篇 |
| 1995年 | 24349篇 |
| 1994年 | 22525篇 |
| 1993年 | 21241篇 |
| 1992年 | 77233篇 |
| 1991年 | 74915篇 |
| 1990年 | 72687篇 |
| 1989年 | 69787篇 |
| 1988年 | 63966篇 |
| 1987年 | 62667篇 |
| 1986年 | 59089篇 |
| 1985年 | 56467篇 |
| 1984年 | 42125篇 |
| 1983年 | 35460篇 |
| 1982年 | 21145篇 |
| 1981年 | 18725篇 |
| 1980年 | 17719篇 |
| 1979年 | 37894篇 |
| 1978年 | 26662篇 |
| 1977年 | 23054篇 |
| 1976年 | 20696篇 |
| 1975年 | 22362篇 |
| 1974年 | 26143篇 |
| 1973年 | 25131篇 |
| 1972年 | 23530篇 |
| 1971年 | 21867篇 |
| 1970年 | 20026篇 |
| 1969年 | 19008篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
21.
22.
Aasha I. Hoogland Hailey W. Bulls Brian D. Gonzalez Brent J. Small Lianqi Liu Joseph Pidala Heather S.L. Jim Asmita Mishra 《Journal of pain and symptom management》2019,57(5):952-960.e1
Context
Quality of life (QoL) is increasingly recognized as an important outcome of cancer treatment. Previous studies have examined clinical predictors of QoL, but with the increasing prevalence of wearable sensors that monitor sleep and activity patterns, further investigation into whether these behaviors are predictive of post-treatment QoL is now feasible. Among patients receiving aggressive cancer treatment such as hematopoietic cell transplantation (HCT), analysis of circadian rhythms (24-hour patterns of sleep and activity) via wearable sensors is limited.Objective
To evaluate the relationship between overall QoL and circadian rhythms in patients receiving allogeneic HCT.Methods
Patients wore an ActiGraph GT3X (Pensacola, FL) activity monitor for at least 72 hours before the initiation of conditioning chemotherapy and transplantation and completed a QoL (Functional Assessment of Cancer Therapy-General [FACT-G]) assessment. QoL assessments were also completed 1, 3, and 6 months after HCT.Results
Patients (n = 45, M age = 55) were mostly male (66%) with a total FACT-G score of 80.96 (SD = 16.05) before HCT. Mixed models revealed robust cross-sectional associations between overall QoL and multiple circadian rhythmicity parameters, including durations of high physical activity, overall circadian rhythmicity, and earlier starts of daily activity (P's < .01). Recovery of QoL after transplant was predicted by longer pre-transplant durations of high physical activity (P = .04) and earlier evening retirement (P = .04).Conclusion
Our findings suggest that wearable sensor information is a promising method of predicting recovery of QoL after HCT. Additional studies are needed to confirm these findings in a larger sample. 相似文献23.
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24.
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25.
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26.
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
Objective
Arteriovenous fistulas created in patients with chronic kidney disease often lose patency and fail to become usable. This prospective trial evaluated the efficacy of vonapanitase, a recombinant human elastase, in promoting radiocephalic fistula patency and use for hemodialysis.Methods
PATENCY-1 was a double-blind, placebo-controlled trial that enrolled 349 patients on or approaching hemodialysis and being evaluated for radiocephalic arteriovenous fistula creation. Of these, 313 were randomized and 311 treated. Patients were assigned to vonapanitase (n = 210) or placebo (n = 103). The study drug solution was applied topically to the artery and vein for 10 minutes immediately after fistula creation. The primary and secondary end points were primary patency (time to first thrombosis or corrective procedure) and secondary patency (time to abandonment). Tertiary end points included use of the fistula for hemodialysis, fistula maturation by ultrasound, and procedure rates.Results
The Kaplan-Meier estimates of 12-month primary patency were 42% (95% confidence interval [CI], 35-49) and 31% (95% CI, 21-42) for vonapanitase and placebo (P = .25). The Kaplan-Meier estimates of 12-month secondary patency were 74% (95% CI, 68-80) and 61% (95% CI, 51-71) for vonapanitase and placebo (P = .048). The proportions of vonapanitase and placebo patients were 39% and 25% (P = .035) with unassisted use for hemodialysis and 64% and 44% (P = .006) with unassisted plus assisted use.Conclusions
Vonapanitase treatment did not significantly improve primary patency but was associated with increased secondary patency and use for hemodialysis. Further research is needed to evaluate these end points. 相似文献27.
S. Kim M.J. Graham R.G. Lee L. Yang S. Kim V. Subramanian J.D. Layne L. Cai R.E. Temel D. Shih A.J. Lusis J.A. Berliner S. Lee 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2019,29(3):306-315
Background and aims
Heparin-binding EGF-like growth factor (HB-EGF) is a representative EGF family member that interacts with EGFR under diverse stress environment. Previously, we reported that the HB-EGF-targeting using antisense oligonucleotide (ASO) effectively suppressed an aortic aneurysm in the vessel wall and circulatory lipid levels. In this study, we further examined the effects of the HB-EGF ASO administration on the development of hyperlipidemia-associated atherosclerosis using an atherogenic mouse model.Methods and results
The male and female LDLR deficient mice under Western diet containing 21% fat and 0.2% cholesterol content were cotreated with control and HB-EGF ASOs for 12 weeks. We observed that the HB-EGF ASO administration effectively downregulated circulatory VLDL- and LDL-associated lipid levels in circulation; concordantly, the HB-EGF targeting effectively suppressed the development of atherosclerosis in the aorta. An EGFR blocker BIBX1382 administration suppressed the hepatic TG secretion rate, suggesting a positive role of the HB-EGF signaling for the hepatic VLDL production. We newly observed that there was a significant improvement of the insulin sensitivity by the HB-EGF ASO administration in a mouse model under the Western diet as demonstrated by the improvement of the glucose and insulin tolerances.Conclusion
The HB-EGF ASO administration effectively downregulated circulatory lipid levels by suppressing hepatic VLDL production rate, which leads to effective protection against atherosclerosis in the vascular wall. 相似文献28.
P. Mendogni S. Henchi L.C. Morlacchi D. Tosi M. Nosotti P. Tarsia A.I. Gregorini L. Rosso 《Transplantation proceedings》2019,51(1):194-197
Background
Solid organ transplantation is associated with a higher risk of Epstein-Barr virus (EBV)–related lymphoproliferative disease due to immunosuppressive regimen. Little evidence is currently available on post-transplant lymphoproliferative disorders (PTLDs) in the lung transplant (LuTx) setting, particularly in cystic fibrosis (CF) recipients.Methods
We retrospectively analyzed all the cases of PTLDs that occurred in our LuTx center between January 2015 and December 2017. We reviewed clinical and radiologic data, donor and recipient EBV serostatus, immunosuppressive therapy, histologic data, and follow-up of these patients.Results
A total of 77 LuTxs were performed at our center in the study period; 39 (50.6%) patients had CF; 4 developed EBV-related PTLDs. They were all young (17–26 years) CF patients with high serum EBV DNA load. Disease onset was within the first 3 months after LuTx. In 3 cases presentation was associated with fever and infection-like symptoms, whereas in 1 case radiologic suspicion arose unexpectedly from a CT scan performed for different clinical reasons. Diagnosis was reached through lung biopsy in all cases. All patients received rituximab,?cyclophosphamide, doxorubicin hydrochloride (hydroxydaunomycin), vincristine sulfate (Oncovin), and prednisone with variable response and complications.Conclusion
In our experience, the early development of EBV-related PTLD was a highly aggressive, life-threatening condition, which exclusively affected young CF patients in the early post-transplant period. The rate of this complication was relatively high in our population.Diagnosis with lung biopsy is crucial in all suspected cases and regular monitoring of EBV DNA levels is of utmost importance given the high correlation with PTLDs in patients at increased risk. 相似文献29.
Neuroinflammation is initiated as a result of traumatic brain injury and can exacerbate evolving tissue pathology. Immune cells respond to acute signals from damaged cells, initiate neuroinflammation, and drive the pathological consequences over time. Importantly, the mechanism(s) of injury, the location of the immune cells within the brain, and the animal species all contribute to immune cell behavior following traumatic brain injury. Understanding the signals that initiate neuroinflammation and the context in which they appear may be critical for understanding immune cell contributions to pathology and regeneration.Within this paper, we review a number of factors that could affect immune cell behavior acutely following traumatic brain injury. 相似文献
30.
Andreu Porta-Sánchez Andrew C.T. Ha Xuesong Wang Fahad Almehmadi Peter C. Austin Hadas D. Fischer Atif Al-Qubbany Diego Chemello Vijay Chauhan Eugene Downar Douglas S. Lee Kumaraswamy Nanthakumar 《The Canadian journal of cardiology》2019,35(2):169-177