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   290篇
  免费   13篇
耳鼻咽喉   2篇
儿科学   8篇
妇产科学   2篇
基础医学   67篇
口腔科学   5篇
临床医学   28篇
内科学   47篇
皮肤病学   4篇
神经病学   29篇
特种医学   12篇
外科学   35篇
综合类   3篇
预防医学   21篇
眼科学   1篇
药学   17篇
肿瘤学   22篇
  2023年   3篇
  2022年   3篇
  2021年   7篇
  2020年   2篇
  2019年   5篇
  2018年   5篇
  2017年   6篇
  2016年   4篇
  2015年   7篇
  2014年   11篇
  2013年   15篇
  2012年   25篇
  2011年   32篇
  2010年   17篇
  2009年   16篇
  2008年   28篇
  2007年   23篇
  2006年   12篇
  2005年   13篇
  2004年   18篇
  2003年   19篇
  2002年   7篇
  2001年   1篇
  2000年   2篇
  1998年   2篇
  1997年   2篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1993年   3篇
  1992年   3篇
  1990年   1篇
  1988年   1篇
  1987年   3篇
  1984年   3篇
  1961年   1篇
排序方式: 共有303条查询结果,搜索用时 15 毫秒
241.
This study evaluated whether first-pass perfusion cardiovascular magnetic resonance (FP-CMR) could predict the hemodynamic significance of epicardial coronary artery stenosis as defined by invasively determined fractional flow reserve at coronary angiography. In 19 patients with known coronary artery disease (CAD), the hemodynamic relevance of 22 stenoses (mean angiographic severity 73 +/- 9%) was determined using fractional flow reserve measurements (cutoff 0.75). Results were compared with a territorial index of myocardial perfusion reserve (MPR) derived from FP-CMR. In addition, 9 age-matched patients with low prevalence of risk factors and without CAD at angiography served as a control group. A cutoff of 1.5 for MPR separated hemodynamically relevant from nonrelevant stenoses with a sensitivity and specificity of 92% and 92%, respectively. The area under the receiver-operator characteristic curve was 0.97. In the patient group, territories supplied by arteries without significant stenosis (相似文献   
242.
243.
244.
Human and mouse studies indicate distinct roles of selected chemokines for monocyte subset attraction. We therefore analyzed the still unknown sensitivity and response of bovine monocyte subsets toward two monocyte-attracting chemokines (CCL2, CCL5). Only CCL5 induced a significant Ca2+influx and migration response in bovine monocytes, with classical and intermediate monocytes being significantly stimulated and attracted compared to nonclassical monocytes. The presence of CCL5 during in vitro macrophage differentiation did not alter their capacity to phagocytize or to generate reactive oxygen species upon stimulation with E. coli. However, macrophages differentiated in the presence of CCL5 displayed an altered phenotype with significantly less expressed CD14 and MHC class II molecules, whereas CD16 was upregulated. Moreover, CCL5-differentiated macrophages displayed a reduced upregulation of CXCL8, ARG1, IL6 and IL10 mRNA. Taken together, CCL5 but not CCL2 mainly attract bovine classical monocytes and promote their differentiation into LPS-hypo-responsive macrophages.  相似文献   
245.
Abstract

Reanimation of paralysed facial muscles by electrical stimulation has been studied extensively in animal models, but human studies in this field are largely lacking. Twenty-four subjects with a peripheral facial nerve palsy with a median duration of three years were enrolled. We studied activations of four facial muscles with electrical stimulation using surface electrodes. In subjects whose voluntary movement was severely impaired or completely absent, the electrical stimulation produced a movement that was greater in amplitude compared with the voluntary effort in 10 out of 18 subjects in the frontalis muscle, in 5 out of 14 subjects in the zygomaticus major muscle, and in 3 out of 8 subjects in the orbicularis oris muscle. The electrical stimulation produced a stronger blink in 8 subjects out of 22 compared with their spontaneous blinks. The stimulation could produce a better movement even in cases where the muscles were clinically completely paretic, sometimes also in palsies that were several years old, provided that the muscle was not totally denervated. Restoring the function of paralysed facial muscles by electrical stimulation has potential as a therapeutic option in cases where the muscle is clinically paretic but has reinnervation.  相似文献   
246.
An open,noncomparative, Nordic multicenter study was carried out during 1991–1992 to evaluate the 5-HT3 receptor antagonist tropisetron (Navoban) as an antiemetic agent for various types of cancer chemotherapy. A total of 630 patients were recruited from 15 centers in Sweden, Denmark, and Finland. Gynecological cancers (60%), breast cancer (15%), and lung cancer (10%) were the main diagnoses. Prior experience of chemotherapy was documented in 338 patients (54%). In 260 patients (41%), cisplatin was part of the cytostatic regimen. Carboplatin (23%), doxorubicin (27%), and epidoxorubicin (24%) were also frequently included. In all, 23 cytostatic agents were used in various combinations. The mean number of courses studied was 4.6 (range 1–19). Altogether, 394 of 619 evaluable patients (64%) were completely protected from acute nausea and vomiting during the first course of chemotherapy. Delayed nausea and vomiting were completely prevented in 45%–73% (days 2–6) in the complete series. Treatment efficacy remained stable (60%–79%) during ten consecutive courses of chemotherapy. With noncisplatin regimens, complete protection from acute nausea and vomiting was achieved in 72% compared with 52% for cisplatin regimens (P<0.0001). Patients without prior experience of chemotherapy had higher control rates of acute nausea and vomiting (72%) compared to patients treated before (57%) during the first course,but not later on. There were no differences in delayed nausea and vomiting. Sex and age were significant prognostic factors with regard to antiemetic response. Adverse events were recorded in 19%–37% of the cases during long-term follow-up. Headache (18%) and constipation (8%) were most frequent. The side effects were mild, however, and tropisetron (Navoban) was a safe drug and was well tolerated by the patients.  相似文献   
247.
Children with certain risk factors, such as comorbidities or severe obstructive sleep apnea syndrome (OSAS) are known to require extended postoperative monitoring after adenotonsillectomy. However, there are no recommendations available for diode-laser-assisted tonsillotomy. A retrospective chart review of 96 children who underwent diode-laser-assisted tonsillotomy (07/2011–06/2013) was performed. Data for general and sleep apnea history, power of the applied diode-laser (λ = 940 nm), anesthesia parameters, the presence of postoperative respiratory complications and postoperative healing were evaluated. After initially uncomplicated diode-laser-assisted tonsillotomy, an adjustment of post-anesthesia care was necessary in 16 of 96 patients due to respiratory failure. Respiratory complications were more frequent in younger children (3.1 vs. 4.0 years, p = 0.049, 95 % CI ?1.7952 to ?0.0048) and in children who suffered from nocturnal apneas (OR = 5.00, p < 0.01, 95 % CI 1.4780–16.9152) or who suffered from relevant comorbidities (OR = 4.84, p < 0.01, 95 % CI 1.5202–15.4091). Moreover, a diode-laser power higher than 13 W could be identified as a risk factor for the occurrence of a postoperative oropharyngeal edema (OR = 3.45, p < 0.01, 95 % CI 1.3924–8.5602). Postoperative respiratory complications should not be underestimated in children with sleep-disordered breathing (SDB). Therefore, children with SDB, children with comorbidities or children younger than 3 years should be considered “at risk” and children with confirmed moderate to severe OSAS should be referred to a PICU following diode-laser-assisted tonsillotomy. We recommend a reduced diode-laser power (<13 W) to reduce oropharyngeal edema.  相似文献   
248.

Introduction

The purpose of this study was to evaluate MR imaging characteristics with conventional and advanced MR imaging techniques in patients with IIDL.

Methods

MR images of the brain in 42 patients (20 male, 22 female) with suspected or known multiple sclerosis (MS) from four institutions were retrospectively analyzed. Lesions were classified into five different subtypes: (1) ring-like lesions; (2) Balo-like lesions; (3) diffuse infiltrating lesions; (4) megacystic lesions; and (5) unclassified lesions.The location, size, margins, and signal intensities on T1WI, T2WI, and diffusion-weighted images (DWI), and the ADC values/ratios for all lesions, as well as the contrast enhancement pattern, and the presence of edema, were recorded.

Results

There were 30 ring-like, 10 Balo-like, 3 megacystic-like and 16 diffuse infiltrating-like lesions were detected. Three lesions were categorized as unclassified lesions.Of the 30 ring-like lesions, 23 were hypointense centrally with a hyperintense rim. The mean ADC, measured centrally, was 1.50 ± 0.41 × 10−3 mm2/s. The mean ADC in the non-enhancing layers of the Balo-like lesions was 2.29 ± 0.17 × 10−3 mm2/s, and the mean ADC in enhancing layers was 1.03 ± 0.30 × 10−3 mm2/s. Megacystic lesions had a mean ADC of 2.14 ± 0.26 × 10−3 mm2/s. Peripheral strong enhancement with high signal on DWI was present in all diffuse infiltrating lesions. Unclassified lesions showed a mean ADC of 1.43 ± 0.13 mm2/s.

Conclusion

Restriction of diffusion will be seen in the outer layers of active inflammation/demyelination in Balo-like lesions, in the enhancing part of ring-like lesions, and at the periphery of infiltrative-type lesions.  相似文献   
249.
The cause of Bell's palsy remains unknown even though available evidence suggests that infection could be a factor. In recent studies, Chlamydia pneumoniae has been associated with neurologic diseases such as multiple sclerosis. In the present study, the association of C pneumoniae with Bell's palsy was studied with the use of serology and polymerase chain reaction to test tear fluid and peripheral blood mononuclear cells from 21 patients with Bell's palsy and 21 control subjects. C pneumoniae DNA was detected from tear fluid samples in 1 patient with Bell's palsy and in 2 healthy control subjects. Whether this indicates earlier disease or subclinical infection remains to be studied. However, an association between Bell's palsy and acute C pneumoniae infection could not be shown.  相似文献   
250.
Confocal laser scanning microscopy (CLSM) was introduced and examined as a novel technique for imaging film-core interface and surface defects of film-coated tablets. Tablets of acetylsalicylic acid, microcrystalline cellulose (MCC) and lactose monohydrate were film-coated with aqueous hydroxypropyl methylcellulose using an instrumented side-vented pan coater. The film coatings were applied using 100- and 500-kPa spraying air pressures. The CLSM images of the coating surface were compared with surface roughness measurements using a laser profilometer and an optical roughness analyzer. The spraying air pressure affected the film-core interface and the occurrence of coating defects. With the lower spraying pressure the aqueous coating solution penetrated into the tablet core, the core components migrated to the coating layer, and the film coating surface was clearly rougher compared to the higher spraying pressure. Storage at 25 degrees C/60% RH or 40 degrees C/75% RH for 3 months expanded the MCC-containing tablet core impaired the film structure and increased the film roughness. Based on the present results, CLSM is an effective tool for imaging film-core interface and surface defects of film-coated tablets. The CLSM images are supported by the results obtained with the other surface roughness measuring techniques.  相似文献   
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