全文获取类型
收费全文 | 621篇 |
免费 | 53篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 17篇 |
妇产科学 | 21篇 |
基础医学 | 101篇 |
口腔科学 | 8篇 |
临床医学 | 70篇 |
内科学 | 123篇 |
皮肤病学 | 25篇 |
神经病学 | 38篇 |
特种医学 | 25篇 |
外科学 | 53篇 |
综合类 | 1篇 |
一般理论 | 1篇 |
预防医学 | 87篇 |
眼科学 | 3篇 |
药学 | 60篇 |
肿瘤学 | 37篇 |
出版年
2024年 | 2篇 |
2023年 | 11篇 |
2022年 | 14篇 |
2021年 | 25篇 |
2020年 | 17篇 |
2019年 | 21篇 |
2018年 | 39篇 |
2017年 | 21篇 |
2016年 | 23篇 |
2015年 | 33篇 |
2014年 | 23篇 |
2013年 | 32篇 |
2012年 | 61篇 |
2011年 | 67篇 |
2010年 | 26篇 |
2009年 | 25篇 |
2008年 | 39篇 |
2007年 | 31篇 |
2006年 | 33篇 |
2005年 | 33篇 |
2004年 | 23篇 |
2003年 | 16篇 |
2002年 | 12篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1969年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有675条查询结果,搜索用时 953 毫秒
1.
2.
Ragnhild B. Wijma Marloes Emous Merel van den Broek Anke Laskewitz Anneke C. Muller Kobold André P. van Beek 《Surgery for obesity and related diseases》2019,15(1):73-81
Background
Early dumping is a poorly defined and incompletely understood complication after Roux-en-Y gastric (RYGB).Objective
We performed a mixed-meal tolerance test in patients after RYGB to address the prevalence of early dumping and to gain further insight into its pathophysiology.Setting
The study was conducted in a regional hospital in the northern part of the Netherlands.Methods
From a random sample of patients who underwent primary RYGB between 2008 and 2011, 46 patients completed the mixed-meal tolerance test. The dumping severity score for early dumping was assessed every 30 minutes. A sum score at 30 or 60 minutes of ≥5 and an incremental score of ≥3 points were defined as indicating a high suspicion of early dumping. Blood samples were collected at baseline, every 10 minutes during the first half hour, and at 60 minutes after the start.Results
The prevalence of a high suspicion of early dumping was 26%. No differences were seen for absolute hematocrit value, inactive glucagon-like peptide-1, and vasoactive intestinal peptide between patients with or without early dumping. Patients at high suspicion of early dumping had higher levels of active glucagon-like peptide-1 and peptide YY.Conclusion
The prevalence of complaints at high suspicion of early dumping in a random population of patients after RYGB is 26% in response to a mixed-meal tolerance test. Postprandial increases in both glucagon-like peptide-1 and peptide YY are associated with symptoms of early dumping, suggesting gut L-cell overactivity in this syndrome. 相似文献3.
Tumor necrosis factor-related apoptosis-inducing ligand can induce apoptosis in subsets of premalignant cells 总被引:2,自引:0,他引:2 下载免费PDF全文
Lu X Arbiser JL West J Hoedt-Miller M Sheridan A Govindarajan B Harral JW Rodman DM Fouty B 《The American journal of pathology》2004,165(5):1613-1620
During the transformation from a normal to a malignant cell, several mutations are required to bypass the pathways responsible for controlling proliferation. Premalignant cells have acquired some, but not all of these mutations and consequently have not yet attained a malignant phenotype characterized by tumor formation in vivo. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can induce apoptosis in malignant cells while sparing normal ones and is currently being considered as adjuvant therapy for various human malignancies. Whether TRAIL is effective in inducing apoptosis in premalignant cells is unclear, however. We studied the effect of TRAIL on two human premalignant cell lines the SV7tert and HA1E cells. Both cell lines had been immortalized by the addition of simian virus 40 large T antigen and the telomerase subunit hTERT, but had not been transformed into malignant cells. TRAIL initiated apoptosis by activating both the mitochondrial-independent and -dependent apoptotic pathways in both cell lines at relatively low doses whereas it had no effect on normal human pulmonary artery smooth muscle cells even at high doses. These results suggest that TRAIL can induce apoptosis in premalignant cells and suggests a novel therapy for the treatment of premalignant lesions in vivo. 相似文献
4.
Geskus RB Meyer L Hubert JB Schuitemaker H Berkhout B Rouzioux C Theodorou ID Delfraissy JF Prins M Coutinho RA 《Journal of acquired immune deficiency syndromes (1999)》2005,39(3):321-326
OBJECTIVE: To investigate the causal pathways by which age and the CCR5-Delta32, CCR2-64I, and SDF-1 3'A alleles influence progression to AIDS. DESIGN: Analysis of follow-up data from 2 cohort studies among homosexual men (n=400), having >10 years of follow-up. METHODS: The effects of the 4 cofactors on the CD4 and HIV-1 RNA trajectories after seroconversion were modeled in a random-effects model. A proportional hazards model was used to investigate their effect on the risk of AIDS after correction for CD4 cell count and RNA level. This approach allows investigation as to whether they influence AIDS progression by affecting CD4 count and RNA level or by other pathways. RESULTS: Persons of younger age or having the CCR2-64I or SDF-1 3'A mutation have significantly higher CD4 levels. Persons with the CCR5-Delta32 deletion or CCR2-64I mutation have significantly lower RNA levels. After correction for both CD4 count and RNA level, only the SDF-1 3'A mutation significantly increases the AIDS risk. CONCLUSIONS: Age and the CCR5-Delta32 deletion and CCR2-64I mutation influence AIDS progression by affecting CD4 and HIV-1 RNA. The SDF-1 3'A allele increases the AIDS risk, but this effect is countered by its effect on CD4 and HIV-1 RNA level. 相似文献
5.
Understanding laboratory testing in diagnostic uncertainty: a qualitative study in general practice. 总被引:2,自引:0,他引:2 下载免费PDF全文
Trudy van der Weijden Marloes A van Bokhoven Geert-Jan Dinant Cathelijne M van Hasselt Richard P T M Grol 《The British journal of general practice》2002,52(485):974-980
BACKGROUND: Better knowledge of the professional's motives for ordering laboratory tests in the case of diagnostic uncertainty may lead to interventions directed at reducing unnecessary testing. AIM: To gain insight into the general practitioner's (GP's) motives for ordering laboratory tests for patients presenting with unexplained complaints. DESIGN OF STUDY: Semi-structured interviews based on surgery observations. SETTING: Twenty-one general practices in rural and urban areas of The Netherlands. METHOD: Investigation of the GP's perception of determinants of test-ordering behaviour in the situation of diagnostic uncertainty. The interviews were structured by evaluating the consultations and test-ordering performance of that day. RESULTS: Dutch GPs vary considerably in their motives for ordering tests. Numerous motives emerged from the data. Some examples of important themes include: personal routines; tolerance of diagnostic uncertainty; time pressure; and tactical motives for test ordering. Complying with the perceived needs of the patient for reassurance through testing is seen as an easy, cost- and time-effective strategy. A clear hierarchy in the determinants was not found. CONCLUSION: The decision to request laboratory testing is the result of a complex interaction of considerations that are often conflicting. Designers of interventions meant to improve the ordering of tests should be aware of the numerous determinants, and take contextual variables into account. 相似文献
6.
Camilla Audia Frans Berkhout George Owusu Zahidul Quayyum Samuel Agyei-Mensah 《Journal of urban health》2021,98(3):394
This paper sets out a structured process for the co-production of knowledge between researchers and societal partners and illustrates its application in an urban health equity project in Accra, Ghana. The main insight of this approach is that research and knowledge co-production is always partial, both in the sense of being incomplete, as well as being circumscribed by the interests of participating researchers and societal partners. A second insight is that project-bound societal engagement takes place in a broader context of public and policy debate. The approach to co-production described here is formed of three recursive processes: co-designing, co-analysing, and co-creating knowledge. These ‘co-production loops’ are themselves iterative, each representing a stage of knowledge production. Each loop is operationalized through a series of research and engagement practices, which we call building blocks. Building blocks are activities and interaction-based methods aimed at bringing together a range of participants involved in joint knowledge production. In practice, recursive iterations within loops may be limited due of constraints on time, resources, or attention. We suggest that co-production loops and building blocks are deployed flexibly. 相似文献
7.
8.
R C Hoogeveen P J Guicherit S R Gopie P F van der Stelt W E R Berkhout 《Dento maxillo facial radiology》2014,43(3)
The use of an anatomically shaped cranial collimator (ACC) to reduce patient dose in orthodontic lateral cephalography was investigated in this study. The aim was to evaluate the potential interference of the ACC on landmark identification for orthodontic cephalometry. Consecutive orthodontic patients underwent a total of 100 cephalograms using an ACC mounted on a Veraviewepocs® 3D X550 (J. Morita Co., Kyoto, Japan) X-ray unit. 10 observers were asked whether the identification of 5 landmarks close to the collimated area was hindered or rendered impossible by the presence of the collimator. Of the 500 landmarks that were judged by the 10 observers, 496 (99.2%) were reported to lack hindrance. In three landmarks, a minority of the observers reported hindrance. In 1 landmark, 8 of the 10 observers reported hindrance by the collimator. In no instance did the observers state that the identification of landmarks was impossible as a result of the collimation. Application of the ACC on the cephalostat of the X-ray unit is a viable way of reducing patient dose, as it only marginally interferes with the diagnostic yield of the exposure. The need to retake images when the ACC is applied was found to be extremely low. 相似文献
9.
10.
W E R Berkhout A Suomalainen D Brüllmann R Jacobs K Horner H C Stamatakis 《Dento maxillo facial radiology》2015,44(6)
Handheld portable X-ray devices are increasingly used for intraoral radiography. This development introduces new challenges to staff and patient safety, for which new or revised risk assessments must be made and acted upon prior to use. Major issues might be: difficulties in using rectangular collimation with beam aiming devices, more complex matching of exposure settings to the X-ray receptor used (e.g. longer exposure times), movements owing to the units'' weight, protection of the operator and third persons, and the use in uncontrolled environments. These problems may result in violation of the “as low as reasonably achievable’’, that is, ALARA principle by an increase in (re)exposures compared with the other available intraoral X-ray devices. Hence, the use of handheld portable X-ray devices should be considered only after careful and documented evaluation (which might be performed based on medical physics support), when there is evidence that handheld operation has benefits over traditional modalities and when no new risks to the operators and/or third parties are caused. It is expected that the use of handheld portable X-ray devices will be very exceptional, and for justified situations only. Special attention should be drawn to beam-aiming devices, rectangular collimation, the section of the X-ray receptor, focus–skin distance, and backscatter shielding, and that the unit delivers reproducible dose over the full set of environmental conditions (e.g. battery status and temperature). 相似文献