全文获取类型
收费全文 | 2480篇 |
免费 | 309篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 66篇 |
妇产科学 | 40篇 |
基础医学 | 234篇 |
口腔科学 | 44篇 |
临床医学 | 350篇 |
内科学 | 650篇 |
皮肤病学 | 32篇 |
神经病学 | 230篇 |
特种医学 | 115篇 |
外科学 | 451篇 |
综合类 | 25篇 |
预防医学 | 190篇 |
眼科学 | 42篇 |
药学 | 137篇 |
中国医学 | 2篇 |
肿瘤学 | 210篇 |
出版年
2023年 | 19篇 |
2022年 | 28篇 |
2021年 | 48篇 |
2020年 | 38篇 |
2019年 | 25篇 |
2018年 | 49篇 |
2017年 | 57篇 |
2016年 | 72篇 |
2015年 | 111篇 |
2014年 | 179篇 |
2013年 | 204篇 |
2012年 | 130篇 |
2011年 | 113篇 |
2010年 | 151篇 |
2009年 | 145篇 |
2008年 | 93篇 |
2007年 | 86篇 |
2006年 | 96篇 |
2005年 | 84篇 |
2004年 | 76篇 |
2003年 | 86篇 |
2002年 | 77篇 |
2001年 | 69篇 |
2000年 | 40篇 |
1999年 | 50篇 |
1998年 | 46篇 |
1997年 | 57篇 |
1996年 | 46篇 |
1995年 | 44篇 |
1994年 | 23篇 |
1993年 | 19篇 |
1992年 | 22篇 |
1991年 | 19篇 |
1990年 | 22篇 |
1989年 | 18篇 |
1988年 | 19篇 |
1987年 | 14篇 |
1986年 | 21篇 |
1985年 | 25篇 |
1983年 | 23篇 |
1982年 | 16篇 |
1980年 | 12篇 |
1979年 | 14篇 |
1978年 | 23篇 |
1977年 | 14篇 |
1976年 | 15篇 |
1975年 | 14篇 |
1973年 | 13篇 |
1972年 | 14篇 |
1971年 | 16篇 |
排序方式: 共有2835条查询结果,搜索用时 15 毫秒
71.
Wesley E. Shankland II 《Cranio : the journal of craniomandibular practice》2013,31(4):269-278
Migraine and tension-type headaches have always plagued mankind. In spite of all the research dollars spent trying to determine the etiologies of these headaches, the neurology community still has not established a known cause of migraine and tension type headaches. This paper describes a study that was conducted for the U.S. Food and Drug Administration in which the efficacy of the Nociceptive Trigeminal Inhibition Tension Suppression System was evaluated and proved safe and efficacious in the reduction of medically diagnosed migraine and tension-type headache. 相似文献
72.
Wesley E. Shankland II 《Cranio : the journal of craniomandibular practice》2013,31(4):295-303
Jaw-deviation dystonia is characterized by the lateral shift of the mandible due to involuntary masticatory muscle contraction, causing difficulties in speech or mastication. We evaluated a patient with jaw-deviation dystonia by recording movement-related cortical potentials (MRCPs) and treated with muscle afferent block (MAB). MRCP associated with mandibular movements (mouth opening, closing, and left and right lateral movements) was recorded in the patient and ten age-matched healthy subjects. In the control subjects, the amplitude of Bereitschaftspotential (BP)/negative slope (NS') was significantly higher for left lateral movements than for the mouth closing. The cortical map of BP/NS' prior to mouth opening and closing showed symmetric distribution, whereas those of lateral movements showed a slight predominance in the ipsilateral hemisphere. The patient showed lower amplitude as compared with control subjects. The right lateral movement (homonymous task) showed task-specific markedly reduced potentials. After MAB by intramuscular injection of lidocaine and ethanol to the inferior head of the left lateral pterygoid muscle, the deviation abolished and severity in speech and mastication was significantly improved. This study suggests that jaw-deviation dystonia might have the same etiology as other focal dystonias. 相似文献
73.
74.
M. R. Allen N. X. Chen V. H. Gattone II X. Chen A. J. Carr P. LeBlanc D. Brown S. M. Moe 《Osteoporosis international》2013,24(4):1471-1481
Summary
Bisphosphonates reduce skeletal loss and fracture risk, but their use has been limited in patients with chronic kidney disease. This study shows skeletal benefits of zoledronic acid in an animal model of chronic kidney disease.Introduction
Bisphosphonates are routinely used to reduce fractures but limited data exists concerning their efficacy in non-dialysis chronic kidney disease. The goal of this study was to test the hypothesis that zoledronic acid produces similar skeletal effects in normal animals and those with kidney disease.Methods
At 25 weeks of age, normal rats were treated with a single dose of saline vehicle or 100 μg/kg of zoledronic acid while animals with kidney disease (approximately 30 % of normal kidney function) were treated with vehicle, low dose (20 μg/kg), or high dose (100 μg/kg) zoledronic acid, or calcium gluconate (3 % in the drinking water). Skeletal properties were assessed 5 weeks later using micro-computed tomography, dynamic histomorphometry, and mechanical testing.Results
Animals with kidney disease had significantly higher trabecular bone remodeling compared to normal animals. Zoledronic acid significantly suppressed remodeling in both normal and diseased animals yet the remodeling response to zoledronic acid was no different in normal and animals with kidney disease. Animals with kidney disease had significantly lower cortical bone biomechanical properties; these were partially normalized by treatment.Conclusions
Based on these results, we conclude that zoledronic acid produces similar amounts of remodeling suppression in animals with high turnover kidney disease as it does in normal animals, and has positive effects on select biomechanical properties that are similar in normal animals and those with chronic kidney disease. 相似文献75.
Howard I. Pryor II Adam Singleton Elissa Lin Paul Lin Khashayar Vaziri 《Surgical endoscopy》2013,27(3):843-848
Background
In the morbidly obese population that undergoes bariatric surgery, venous thromboembolism (VTE) is the leading cause of morbidity and mortality. Certain factors place a patient at higher risk for VTE. No consensus exists on VTE screening or prophylaxis for the high-risk patient. This report describes the results of a survey on VTE screening and prophylaxis patterns in high-risk bariatric surgery.Methods
Members of the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) were queried on factors that identified bariatric patients as high risk for VTE and on routine screening and prophylaxis practices. This included mechanical and chemical prophylaxis, duration of therapy, and use of inferior vena cava (IVC) filters.Results
Of the 385 surgeons who responded to the survey, 81 % were bariatric surgeons, and the majority managed more than 50 cases annually. One or more of the following risk factors qualified patients as high risk: history of VTE, hypercoagulable status, body mass index (BMI) exceeding 55 kg/m2, partial pressure of arterial oxygen (PaO2) lower than 60 mmHg, and severe immobility. Preoperative screening of patients for VTE was practiced routinely by 56 % of the surgeons, and 92.4 % used preoperative chemoprophylaxis. The most common agent used preoperatively was heparin (48 %), and Lovenox was most commonly used postoperatively (49 %). Whereas 48 % of the patients discontinued chemoprophylaxis at discharge, 43 % continued chemoprophylaxis as outpatients, and 47 % routinely screened for VTE postoperatively. Use of IVC filters was routine for 28 % of the patients, who most commonly removed them after 1–3 months.Conclusions
This study describes current practice patterns of VTE screening and prophylaxis in high-risk bariatric surgery. Nearly all surgeons agree on risk factors that qualify patients as high risk, but only half routinely screen patients preoperatively. Preoperative VTE chemoprophylaxis is used by nearly all surgeons, but the duration of therapy varies. Use of IVC filters is not routine, and postoperative screening was performed by less than half of the respondents. An understanding of current practice patterns yields insight into the rates of VTE and shows variability in the need for evidence-based prophylaxis and standardized screening. 相似文献76.
Jina Pakpoor Micheal Raad Andrew Harris Varun Puvanesarajah Joseph K. Canner Rohini Nadgir Amit Jain 《Journal of the American College of Radiology》2019,16(11):1522-1527
ObjectiveHigh-value care guidelines from multiple medical societies recommend against imaging for the initial evaluation of low back pain in the absence of red flag symptoms. We aimed to determine the current temporal and geographic landscape of imaging ordering patterns for this indication among US primary care providers.MethodsUsing a national commercial insurance claims database, we identified patients between 18 and 64 years old who presented to a primary care provider for an initial evaluation of low back pain between 2011 and 2016. Patients were identified via International Classification of Diseases codes, and the use of diagnostic imaging was identified by Current Procedural Terminology codes. Geographic regions were based on the location of patient residence.ResultsOverall, 627,118 encounters met inclusion criteria. Imaging acquisitions increased over time, from 14% of encounters in 2011 to 16% in 2016 (P < .01). Radiographs represented 96% of ordered imaging, CT 2%, and MRI 3%. The likelihood of having any imaging for low back pain varied significantly by US census region and by US state (P < .01). The greatest use of imaging was in the Midwest (13.9%) and the South (18.5%), and lowest in the Northeast and West (6.2% and 13.6%).DiscussionImaging utilization for the initial evaluation of low back pain by primary care providers has increased on a national level from 2011 to 2016, largely represented by radiographs. Significant regional variation also exists. Encouragingly, the use of advanced imaging has remained at a low level in the primary care setting (<1.0%). 相似文献
77.
Segmentation of 4D cardiac MR images using a probabilistic atlas and the EM algorithm 总被引:3,自引:0,他引:3
Lorenzo-Valdés M Sanchez-Ortiz GI Elkington AG Mohiaddin RH Rueckert D 《Medical image analysis》2004,8(3):255-265
In this paper an automatic atlas-based segmentation algorithm for 4D cardiac MR images is proposed. The algorithm is based on the 4D extension of the expectation maximisation (EM) algorithm. The EM algorithm uses a 4D probabilistic cardiac atlas to estimate the initial model parameters and to integrate a priori information into the classification process. The probabilistic cardiac atlas has been constructed from the manual segmentations of 3D cardiac image sequences of 14 healthy volunteers. It provides space and time-varying probability maps for the left and right ventricles, the myocardium, and background structures such as the liver, stomach, lungs and skin. In addition to using the probabilistic cardiac atlas as a priori information, the segmentation algorithm incorporates spatial and temporal contextual information by using 4D Markov Random Fields. After the classification, the largest connected component of each structure is extracted using a global connectivity filter which improves the results significantly, especially for the myocardium. Validation against manual segmentations and computation of the correlation between manual and automatic segmentation on 249 3D volumes were calculated. We used the 'leave one out' test where the image set to be segmented was not used in the construction of its corresponding atlas. Results show that the procedure can successfully segment the left ventricle (LV) (r = 0.96), myocardium (r = 0.92) and right ventricle (r = 0.92). In addition, 4D images from 10 patients with hypertrophic cardiomyopathy were also manually and automatically segmented yielding a good correlation in the volumes of the LV (r = 0.93) and myocardium (0.94) when the atlas constructed with volunteers is blurred. 相似文献
78.
79.
Pure Erythroid Leukemia Mimicking Ewing Sarcoma/Primitive Neuroectodermal Tumor in an Infant 下载免费PDF全文
Razvan Lapadat MD Richard L. Tower MD MS II Wayne Tam MD PhD Attilio Orazi MD Gabriela Gheorghe MD 《Pediatric blood & cancer》2016,63(5):935-937
Pure erythroid leukemia (PEL) is a rare type of acute myeloid leukemia (AML) with a very aggressive clinical course. Presentation as a myeloid/erythroid sarcoma is exceedingly rare. We describe an infantile PEL presenting as a multifocal myeloid sarcoma, clinically and pathologically mimicking Ewing sarcoma/PNET family of tumors. The patient died 8 weeks after the initial presentation due to widespread disease. Our case shows that PEL needs to be considered in the differential diagnosis of small round blue cell tumors in infancy. A meticulous workup including immunohistochemistry, flow cytometry, molecular, and cytogenetic studies was required to reach the diagnosis. 相似文献
80.