全文获取类型
收费全文 | 874篇 |
免费 | 74篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 5篇 |
妇产科学 | 8篇 |
基础医学 | 119篇 |
口腔科学 | 68篇 |
临床医学 | 138篇 |
内科学 | 182篇 |
皮肤病学 | 6篇 |
神经病学 | 27篇 |
特种医学 | 34篇 |
外科学 | 125篇 |
综合类 | 9篇 |
一般理论 | 2篇 |
预防医学 | 89篇 |
眼科学 | 2篇 |
药学 | 47篇 |
中国医学 | 1篇 |
肿瘤学 | 76篇 |
出版年
2022年 | 7篇 |
2021年 | 18篇 |
2020年 | 14篇 |
2019年 | 16篇 |
2018年 | 21篇 |
2017年 | 15篇 |
2016年 | 17篇 |
2015年 | 24篇 |
2014年 | 31篇 |
2013年 | 34篇 |
2012年 | 51篇 |
2011年 | 58篇 |
2010年 | 35篇 |
2009年 | 17篇 |
2008年 | 35篇 |
2007年 | 28篇 |
2006年 | 38篇 |
2005年 | 38篇 |
2004年 | 31篇 |
2003年 | 26篇 |
2002年 | 38篇 |
2001年 | 22篇 |
2000年 | 41篇 |
1999年 | 19篇 |
1997年 | 10篇 |
1996年 | 7篇 |
1995年 | 10篇 |
1993年 | 5篇 |
1992年 | 17篇 |
1991年 | 19篇 |
1990年 | 14篇 |
1989年 | 8篇 |
1988年 | 18篇 |
1987年 | 12篇 |
1986年 | 16篇 |
1985年 | 11篇 |
1984年 | 14篇 |
1983年 | 10篇 |
1982年 | 8篇 |
1981年 | 4篇 |
1979年 | 9篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1973年 | 5篇 |
1972年 | 5篇 |
1968年 | 3篇 |
1967年 | 5篇 |
1966年 | 7篇 |
1965年 | 3篇 |
1916年 | 4篇 |
排序方式: 共有950条查询结果,搜索用时 531 毫秒
31.
Introduction
Sodium hypochlorite (NaOCl) irrigation is critical to endodontic success, and several new methods have been developed to improve irrigation efficacy (eg, passive ultrasonic irrigation [PUI] and EndoActivator [EA]). Using a novel spectrophotometric method, this study evaluated NaOCl irrigant extrusion during canal irrigation.Methods
One hundred fourteen single-rooted extracted teeth were decoronated to leave 15 mm of the root length for each tooth. Cleaning and shaping of the teeth were completed using standardized hand and rotary instrumentation to an apical file size #40/0.04 taper. Roots were sealed (not apex), and 54 straight roots (n = 18/group) and 60 curved roots (>20° curvature, n = 20/group) were included. Teeth were irrigated with 5.25% NaOCl by 1 of 3 methods: passive irrigation with needle, PUI, or EA irrigation. Extrusion of NaOCl was evaluated using a pH indicator and a spectrophotometer. Standard curves were prepared with known amounts of irrigant to quantify amounts in unknown samples.Results
Irrigant extrusion was minimal with all methods, with most teeth showing no NaOCl extrusion in straight or curved roots. Minor NaOCl extrusion (1–3 μL) in straight roots or curved roots occurred in 10%–11% of teeth in all 3 irrigant methods. Two teeth in both the syringe irrigation and the EA group extruded 3–10 μL of NaOCl.Conclusions
The spectrophotometric method used in this study proved to be very sensitive while providing quantification of the irrigant levels extruded. Using the PUI or EA tip to within 1 mm of the working length appears to be fairly safe, but apical anatomy can vary in teeth to allow extrusion of irrigant. 相似文献32.
Jonathan M. Evans Carolyn A. Bowles Johannes Bjornsson Charles J. Mullany Gene G. Hunder 《Arthritis \u0026amp; Rheumatology》1994,37(10):1539-1547
Objective. To determine the features and outcomes of patients with giant cell arteritis (GCA) who have aneurysms or rupture of the thoracic aorta. Methods. Patients with GCA seen over a 40-year period who had aneurysms and/or rupture of the thoracic aorta were identified by assistance of a computerized indexing system. The presence of thoracic aortic aneurysms (TAA), with or without aortic valve insufficiency (AI), was determined by radiographs, computed tomography scans, and ultrasound studies of the thorax, angiograms of the aorta, and postmortem examination. Results. Ten men and 31 women with GCA were found to have TAA and/or rupture. Three developed TAA before GCA was diagnosed, 5 developed aortic findings near the time of the diagnosis, and 33 after the diagnosis of GCA (median of 7 years after diagnosis). Sixteen patients developed acute aortic dissection, which caused death in 8. Nineteen patients also had AI due to aortic root dilation, 15 of whom developed congestive heart failure. Eighteen patients underwent 21 surgical procedures for TAA resection and/or aortic valve replacement or repair. Aortitis was documented histologically in 10 cases. Conclusion. Thoracic aortic complications in GCA are associated with serious outcomes that have been underrecognized and may be fatal. Physicians should be alert to the development of these complications at any time in the course of GCA, even many years after usual symptoms have subsided. 相似文献
33.
Jamie A. Moore Jayna J. Mistry Charlotte Hellmich Rebecca H. Horton Edyta E. Wojtowicz Aisha Jibril Matthew Jefferson Thomas Wileman Naiara Beraza Kristian M. Bowles Stuart A. Rushworth 《The Journal of clinical investigation》2022,132(5)
The bone marrow (BM) microenvironment regulates acute myeloid leukemia (AML) initiation, proliferation, and chemotherapy resistance. Following cancer cell death, a growing body of evidence suggests an important role for remaining apoptotic debris in regulating the immunologic response to and growth of solid tumors. Here, we investigated the role of macrophage LC3–associated phagocytosis (LAP) within the BM microenvironment of AML. Depletion of BM macrophages (BMMs) increased AML growth in vivo. We show that LAP is the predominate method of BMM phagocytosis of dead and dying cells in the AML microenvironment. Targeted inhibition of LAP led to the accumulation of apoptotic cells (ACs) and apoptotic bodies (ABs), resulting in accelerated leukemia growth. Mechanistically, LAP of AML-derived ABs by BMMs resulted in stimulator of IFN genes (STING) pathway activation. We found that AML-derived mitochondrial damage–associated molecular patterns were processed by BMMs via LAP. Moreover, depletion of mitochondrial DNA (mtDNA) in AML-derived ABs showed that it was this mtDNA that was responsible for the induction of STING signaling in BMMs. Phenotypically, we found that STING activation suppressed AML growth through a mechanism related to increased phagocytosis. In summary, we report that macrophage LAP of apoptotic debris in the AML BM microenvironment suppressed tumor growth. 相似文献
34.
Bassem Amr Golnaz Shahtahmassebi Christopher D. Briggs Matthew J. Bowles Somaiah Aroori David A. Stell 《HPB : the official journal of the International Hepato Pancreato Biliary Association》2016,18(4):354-359
BackgroundDelay between diagnosis of peri-ampullary cancer (PC) and surgery may allow tumour progression and affect outcome. The aim of this study was to explore associations of interval to surgery (IS) with pathological outcomes and survival in patients with PC.MethodA database review of all patients undergoing surgery between 2006 and 2014 was undertaken. IS was measured from diagnosis by imaging. Potential association between IS and survival was measured using Cox regression analysis, and between IS and pathological outcome with multivariate logistic analysis.Results388 patients underwent surgery. The median IS was 49 days (1–551 days), and was not associated with any of the evaluated outcomes in patients with pancreatic (149) or distal bile duct (46) cancer. For patients with ampullary cancer (71) longer IS was associated with improved survival, with median survival of 27.5 months for patients waiting ≤ median IS (35) and 38.3 months for patients waiting > median IS (36) for surgery (p = 0.041). A higher rate of margin positivity (31.4%) was also noted among patients who waited less than the median IS compared to those waiting longer than this interval (11.4%) (p = 0.032).ConclusionFor patients with ampullary cancer there is a paradoxical improvement in outcome among those with a longer IS, which may be explained by progression to inoperability of more aggressive lesions. 相似文献
35.
Echocardiographic assessment of flow across continuous-flow ventricular assist devices at low speeds
36.
M. S. Yeoman B. D. Reddy H. C. Bowles P. Zilla D. Bezuidenhout T. Franz 《Annals of biomedical engineering》2009,37(11):2266-2287
The mechanics of arteries result from the properties of the soft tissue constituents and the interaction of the wall layers,
predominantly media and adventitia. This concept was adopted in this study for the design of a tissue regenerative vascular
graft. To achieve the desired structural properties of the graft, most importantly a diametric compliance of 6%/100 mmHg,
finite element methods and genetic algorithms were used in an integrated approach to identify the mechanical properties of
an adventitial fabric layer that were required to optimally complement an intimal/medial polyurethane layer with interconnected
porosity of three different size classes. The models predicted a compliance of 16.0, 19.2, and 31.5%/100 mmHg for the non-reinforced
grafts and 5.3, 5.5, and 6.0%/100 mmHg for the fabric-reinforced grafts. The latter, featuring fabrics manufactured according
to the required non-linear mechanical characteristics numerically predicted, exhibited an in vitro compliance of 2.1 ± 0.8, 3.0 ± 2.4, and 4.0 ± 0.7% /100 mmHg. The combination of finite element methods and genetic algorithms
was shown to be able to successfully optimize the mechanical design of the composite graft. The method offers potential for
the application to alternative concepts of modular vascular grafts and the incorporation of tissue ingrowth and biodegradation. 相似文献
37.
Catrine Tudor-Locke Hidde P van der Ploeg Heather R Bowles Michael Bittman Kimberly Fisher Dafna Merom Jonathan Gershuny Adrian Bauman Muriel Egerton 《The international journal of behavioral nutrition and physical activity》2007,4(1):45-9
Background
The American Heritage Time Use Study (AHTUS) represents a harmonised historical data file of time use by adults, amalgamating surveys collected in 1965–66, 1975–76, 1985, 1992–94, and 2003. The objectives of time-use studies have ranged from evaluating household and other unpaid production of goods and services, to monitoring of media use, to comparing lifestyles of more and less privileged social groups, or to tracking broad shifts in social behaviour. The purpose of this paper is to describe the process and utility of identifying and compiling data from the AHTUS to describe a range of walking behaviours collected using time-use survey methods over almost 40 years in the USA. 相似文献38.
The authors detail the process of developing four specific tools for student evaluation of faculty performance at the master's and baccalaureate levels. To accomplish the desired goal of improving instruction, these authors believe student evaluation tools should be tailor-made to the educational setting and mode of delivery. The tools described in this article were developed to evaluate faculty performance in clinical-direct, on-campus laboratory, clinically precepted, and didactic settings. 相似文献
39.
40.
Alpha adrenergic agonists (e.g. vasoconstrictors) represent one of the most commonly used drug classes in dentistry. Although adrenergic agonists have potent vascular effects, recent studies suggest that capsaicin-sensitive nociceptors may express adrenoceptors, suggesting that these drugs may directly modulate the function of an important class of pain-signaling neurons in peripheral tissues. In this study, we tested the hypothesis that adrenergic agonists inhibit activation of peripheral terminals of capsaicin-sensitive fibers innervating dental pulp. Pretreatment with epinephrine or clonidine significantly inhibited capsaicin-evoked release of immunoreactive calcitonin gene-related peptide from superfused bovine dental pulp. These studies suggest that adrenergic agonists may reduce postoperative pain in part via a direct inhibition of capsaicin-sensitive nociceptors. This finding may lead to the development of selective, peripherally acting, adrenergic analgesics. Moreover, because neuropeptide release alters blood flow, it is possible that the vascular effects of these drugs are caused by both vasoconstriction and inhibition of peripheral neuropeptide release. 相似文献