首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   339篇
  免费   20篇
  国内免费   1篇
儿科学   15篇
妇产科学   3篇
基础医学   37篇
口腔科学   4篇
临床医学   30篇
内科学   82篇
皮肤病学   6篇
神经病学   26篇
特种医学   17篇
外科学   61篇
综合类   6篇
预防医学   19篇
眼科学   11篇
药学   29篇
肿瘤学   14篇
  2024年   1篇
  2023年   4篇
  2022年   16篇
  2021年   21篇
  2020年   6篇
  2019年   15篇
  2018年   22篇
  2017年   10篇
  2016年   11篇
  2015年   12篇
  2014年   15篇
  2013年   22篇
  2012年   19篇
  2011年   28篇
  2010年   11篇
  2009年   17篇
  2008年   14篇
  2007年   18篇
  2006年   22篇
  2005年   4篇
  2004年   11篇
  2003年   9篇
  2002年   7篇
  2001年   1篇
  2000年   3篇
  1998年   2篇
  1997年   2篇
  1995年   2篇
  1994年   2篇
  1993年   2篇
  1992年   7篇
  1991年   2篇
  1990年   5篇
  1989年   1篇
  1985年   1篇
  1981年   2篇
  1979年   3篇
  1977年   2篇
  1974年   3篇
  1973年   2篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
排序方式: 共有360条查询结果,搜索用时 11 毫秒
101.
102.
BackgroundPreviously the Centers for Disease Control and Prevention (CDC) recommended targeted hepatitis C virus (HCV) screening for adults born between 1945 and 1965 and individuals with HCV risk factors. In April 2020, the CDC updated their recommendations to now include all individuals 18 years of age and older in settings with HCV prevalence > 0.1%. Few emergency departments (EDs) currently employ this nontargeted screening approach.ObjectivesWe examined how a shift from targeted to nontargeted screening might affect HCV case identification. We hypothesized that nontargeted screening could improve HCV case identification in our ED.MethodsRetrospective review of prospectively collected nontargeted screening data from June 6, 2018 to June 5, 2019 in a large urban academic ED. Patients 18 years of age and older, triaged to the adult or pediatric ED and able to provide consent for HCV testing, were eligible for study inclusion.ResultsThere were 83,864 ED visits and 40,282 unique patients deemed eligible for HCV testing. Testing occurred in 10,630 (26.4%) patients, of which 638 (6%) had positive HCV antibody (Ab+) tests and 214 (2%) had a positive viral load (VL+). Birth cohort-targeted screening would have identified 48% of the patients with Ab+ tests and 47% of those who were VL+. Risk-based targeted screening would increase the number of Ab+ patients to 67% and VL+ to 72%.ConclusionsNontargeted ED-based HCV screening can identify a large number of patients with HCV infection. A shift from targeted to nontargeted screening may result in fewer missed infections but requires further study.  相似文献   
103.
AIM: To determine the prevalence of unsuspected thyroid nodules on contrast enhanced 16and 64-modified discrete cosine transform (MDCT) of the chest, in a population of adult outpatients imaged for indications other than thyroid disease. METHODS: This retrospective study involved review of intravascular contrast-enhanced MDCT scans of the chest from 3077 consecutive adult outpatients, to identify unsuspected thyroid nodules. Exclusion criteria included history of thyroid cancer, known thyroid nodules or thyroid disease and risk factors for thyroid cancer, as evidenced by their medical records. One of 9 radiologists recorded number of nodules, location and bidirectional measurement of largest nodule, as well as amount of thyroid visualized on the chest computed tomography (CT). Presence of nodule was correlated with age, gender, race and percentage of thyroid imaged. RESULTS: A total of 2510 (2510/3077 or 81.6%) study subjects were included in the data analysis; among them,one or more nodules were identified in 629 subjects (629/2510 or 25.1%), with 242 (242/629 or 38.5%) having multiple nodules. Patients with nodule(s) were significantly older than those without (64 ± 13 years vs 58 ± 14 years, P < 0.0001), and female gender was associated with presence of nodule(s) (373/1222 or 30.5% vs 256/1288 or 19.9%, P < 0.0001). Women were also more likely having multiple nodules (167/373 or 44.8%) compared to men (75/256 or 29.3%, P < 0.0001). The majority of nodules (427/629 or 67.9%) were less than 1 cm. CONCLUSION: This retrospective review revealed a prevalence of 25.1% for unsuspected thyroid nodules on contrast-enhanced chest CT.  相似文献   
104.
This is a case report of small cell lung cancer (SCLC) that underwent spontuneous regression. This was associated with severe neuropathy, which was unresponsive to therapy, including corticosteroids andplasmapheresis. We present here the case report and a brief review of the literature.  相似文献   
105.
OBJECTIVE: The characteristics of intracranial tuberculoma on computed tomography (CT) and magnetic resonance imaging (MRI) are not well known. The authors reviewed the features of tuberculoma on CT scans and MRI. The authors also correlated the MRI characteristics on various pulse sequences with neuropathological findings. METHODS: The charts of patients with intracranial tuberculoma were consecutively reviewed during the period from 1988 to 1999. The diagnosis of tuberculoma was based on pathology (n = 19), clinical or neuroimaging response to tuberculous chemotherapy (n = 57), or evidence of systemic tuberculosis (n = 24). Neuropathological specimens of tuberculoma were graded for the amount of fibrosis, gliosis, necrosis, and cell types (lymphocytes, macrophages, plasma cells). RESULTS: One hundred patients (43 men) were identified. The age range was 1 to 75 years (mean = 30 y). The number of lesions ranged from 1 to > 100 (mean = 4.5 lesions/patient). Thirty-one patients had solitary lesions, whereas 69 had multiple lesions. Thirty-seven patients had hydrocephalus. After contrast administration, > 450 lesions were seen on CT and MRI images in all 100 scans. The diameter of these enhancing lesions ranged from 1 mm to 5 cm. Lesions > 1 cm showed varied enhancement, including irregular shapes, ringlike shapes, open rings, and lobular patterns. Targetlike lesions were seen in only 2 patients. Other features included cortical and subcortical infarcts (12 patients), calcification (10% of lesions), edema (33 patients), meningeal enhancement (12 patients), mass effect, and/or midline shift (18 patients). A hypointense core with a hyperintense rim was the most common signal characteristic on T2-weighted MRI. The central hypointensity on T2-weighted and fluid-attenuated inversion recovery (FLAIR) images reflected extensive necrosis and hypercellularity. CONCLUSION: Multiple tuberculomas and infratentorial locations were more common in the authors' patient population than in previous reports. The MRI signal characteristics of intracranial tuberculoma are extremely diverse. An isointense or hypointense core with a hyperintense rim on T2-weighted and FLAIR images is the most common presentation. Core hypointensity of lesions on these images is related to necrosis and the large number of cells.  相似文献   
106.
Thiazide diuretic (TZ) use is associated with higher bone mineral density, whereas loop diuretic (LD) use is associated with lower bone density and incident fracture. Dihydropyridine‐sensitive calcium channels are expressed on parathyroid cells and may play a role in parathyroid hormone (PTH) regulation. The potential for diuretics and calcium‐channel blockers (CCBs) to modulate PTH and calcium homeostasis may represent a mechanism by which they influence skeletal outcomes. We hypothesized that the use of LD and dihydropyridine CCBs is associated with higher PTH, and TZ use is associated with lower PTH. We conducted cross‐sectional analyses of participants treated for hypertension in the Multi‐Ethnic Study of Atherosclerosis who did not have primary hyperparathyroidism or chronic kidney disease (n = 1888). We used adjusted regression models to evaluate the independent association between TZ, LD, and CCB medication classes and PTH. TZ use was associated with lower PTH when compared with non‐TZ use (44.4 versus 46.9 pg/mL, p = 0.02), whereas the use of LD and CCBs was associated with higher PTH when compared with non‐users of each medication class (LD: 60.7 versus 45.5 pg/mL, p < 0.0001; CCB: 49.5 versus. 44.4 pg/mL, p < 0.0001). Adjusted regression models confirmed independent associations between TZ use and lower PTH (β = –3.2 pg/mL, p = 0.0007), and LD or CCB use and higher PTH (LD: β = +12.0 pg/mL, p < 0.0001; CCB: +3.7 pg/mL, p < 0.0001). Among CCB users, the use of dihydropyridines was independently associated with higher PTH (β = +5.0 pg/mL, p < 0.0001), whereas non‐dihydropyridine use was not (β = +0.58 pg/mL, p = 0.68). We conclude that in a large community‐based cohort with normal kidney function, TZ use is associated with lower PTH, whereas LD and dihydropyridine CCB use is associated with higher PTH. These associations may provide a mechanistic explanation linking use of these medications to the development of skeletal outcomes. © 2016 American Society for Bone and Mineral Research.  相似文献   
107.

Background

Post-operative pain relief in chronic pancreatitis (CP) is variable. Our objective was to determine clinical imaging or histopathologic predictor(s) of post-operative pain relief in CP patients undergoing the Whipple or Frey procedure.

Methods

All patients who underwent a Whipple (n?=?30) or Frey procedure (n?=?30) for painful CP between January 2003 and September 2013 were evaluated. A toxic etiology was defined as a history of alcohol use and/or smoking. The pre-operative abdominal CT was evaluated for calcification(s) and main pancreatic duct (MPD) dilation (≥5 mm). The post-operative histopathology was evaluated for severe fibrosis. Clinical imaging and histopathologic features were evaluated as predictors of post-operative pain relief using univariable and multivariable regression analysis.

Results

A total of 60 patients (age 51.6 years, 53 % males) were included in our study, of whom 42 (70 %) reported post-operative pain relief over a mean follow-up of 1.1 years. There were 37 (62 %) patients with toxic etiology, 36 (60 %) each with calcification(s) and MPD dilation. A toxic etiology, calcifications, and severe fibrosis were associated with post-operative pain relief on univariable analysis (all p?<?0.01). However, only a toxic etiology was an independent predictor of post-operative pain relief (OR 5.7, 95 % CI 1.3, 24.5, p?=?0.02).

Conclusion

Only a toxic etiology, and not imaging or histopathologic findings, independently predicts post-operative pain relief in CP patients undergoing the Whipple or Frey procedure.
  相似文献   
108.
Introduction: The re-purposing of the anti-anginal drug perhexiline (PHX) has resulted in symptomatic improvements in heart failure (HF) patients. The inhibition of carnitine palmitoyltransferase-1 (CPT-1) has been proposed as the primary mechanism underlying the therapeutic benefit of PHX. This hypothesis is contentious.

Areas covered: We reviewed the primary literature and patent landscape of PHX from its initial development in the 1960s through to its emergence as a drug beneficial for HF. We focused on its physico-chemistry, molecular targets, tissue accumulation and clinical dosing.

Expert opinion: Dogma that the beneficial effects of PHX are due primarily to potent myocardial CPT-1 inhibition is not supported by the literature and all available evidence point to it being extremely unlikely that the major effects of PHX occur via this mechanism. In vivo PHX is much more likely to be an inhibitor of surface membrane ion channels and also to have effects on other components of cellular metabolism and reactive oxygen species (ROS) generation across the cardiovascular system. However, the possibility that minor effects of PHX on CPT-1 underpin disproportionately large effects on myocardial function cannot be entirely excluded, especially given the massive accumulation of the drug in heart tissue.  相似文献   
109.
110.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号