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   361篇
  免费   18篇
  国内免费   2篇
耳鼻咽喉   6篇
儿科学   27篇
妇产科学   24篇
基础医学   38篇
口腔科学   3篇
临床医学   22篇
内科学   73篇
皮肤病学   34篇
神经病学   16篇
特种医学   7篇
外科学   46篇
综合类   15篇
预防医学   30篇
眼科学   3篇
药学   16篇
中国医学   2篇
肿瘤学   19篇
  2024年   1篇
  2023年   2篇
  2022年   9篇
  2021年   8篇
  2020年   2篇
  2019年   14篇
  2018年   13篇
  2017年   8篇
  2016年   11篇
  2015年   24篇
  2014年   16篇
  2013年   29篇
  2012年   24篇
  2011年   31篇
  2010年   17篇
  2009年   15篇
  2008年   17篇
  2007年   27篇
  2006年   21篇
  2005年   23篇
  2004年   11篇
  2003年   10篇
  2002年   14篇
  2001年   5篇
  2000年   3篇
  1999年   6篇
  1998年   4篇
  1996年   3篇
  1995年   3篇
  1992年   1篇
  1991年   1篇
  1989年   1篇
  1988年   1篇
  1986年   4篇
  1985年   2篇
排序方式: 共有381条查询结果,搜索用时 15 毫秒
1.
AIM: Experiential studies suggest that re-expansion of a collapsed lung may result in pulmonary ischaemia-reperfusion injury. We aimed to evaluate the effect of lung re-expansion on urinary lipid peroxidation products in neonates with pneumothorax. METHODS: This study included 20 mechanically ventilated neonates with pneumothorax, and 18 healthy neonates (controls). A chest tube was inserted immediately following the diagnosis of pneumothorax. Urine samples were obtained just before tube thoracostomy (first period), after one hour (second period), every 12 hours by complete reexpansion (third period). Vital signs and ventilatory parameters were recorded. Urinary lipid peroxidation was evaluated by measurement of thiobarbituric acid-reacting substances (TBARS). RESULTS: No significant difference was found between urinary TBARS concentrations in the first, second and third periods (4.08 +/- 2.4 nmol/L, 2.8 +/- 2.3 nmol/L and 3.3 +/- 2.1 nmol/L, respectively). Control TBARS levels (4.1 +/- 2.1 nmol/L) did not significantly differ from those of the neonates with pneumothorax (p > 0.05). The neonates with pneumothorax had higher heart rates compared to the controls (p < 0.01). When compared with controls, the systolic pressure was lower in all periods (p < 0.01), and diastolic blood pressure was lower only in the first and second period (p < 0.05). Oxygen saturation significantly decreased in the first period compared to saturation of the second period and of controls (p < 0.01). Ventilatory parameters did not show any significant difference between the periods. CONCLUSIONS: This prospective study showed that re-expansion of the lung did not significantly affect urinary TBARS concentration in neonatal pneumothorax. Indirectly, short-term lung collapse followed by re-expansion might not cause a clinically significant reperfusion injury in newborns.  相似文献   
2.
Primary salivary gland carcinoma with neuroendocrine differentiation is of rare occurrence, especially so in the parotid gland. Amongst the various reported primary tumors with neuroendocrine differentiation, acinic cell carcinoma (ACC) one such tumor. A 48 year old lady presented with a gradually increasing right infra-auricular swelling for a period of 1 year which enlarged suddenly in a short period. Contrast Enhanced Computed Tomography (CECT) suggested diagnosis of Pleomorphic Adenoma. Fine Needle Aspiration Cytology (FANC) yielded a cystic fluid suggesting a possibility of Warthin’s tumor or Oncocytic lesion. Intraoperative findings were suggestive of a Warthin’s tumor. Initial histopathological examination of the tumor was suggestive of neuroendocrine carcinoma. However, extensive sectioning revealed peripheral islands of ACC. Immunoexpression of S-100, Neuron specific Enolase (NSE), Chromogranin A and Synaptophysin confirmed the diagnosis. The possibility of neuroendocrine differentiation in a primary salivary gland tumor should be kept in mind whenever a salivary gland tumor shows only neuroendocrine histology.  相似文献   
3.
目的总结单中心低龄婴儿双供肾移植给成人的临床效果。方法回顾性纳入2013年7月至2017年10月华中科技大学同济医学院附属同济医院实施的所有儿童双供肾移植给成人受者共22例临床资料和随访数据。22例供者年龄(2.9±1.7)个月,体重(4.9±1.4)kg,其中15例小于3月龄。受者多为低体重女性成人,体重(46.3±5.6)kg。总结早期移植失败及随访期间移植肾失功或受者死亡原因。根据是否发生单侧移植肾血栓,移植肾功能恢复者又进一步分为双肾存活组和单肾存活组,比较移植肾中-长期功能。结果4例受者在术后早期出现移植失败,包括双肾血栓2例、移植肾破裂切除1例和受者多器官功能衰竭死亡1例。18例受者移植肾功能恢复出院,随访期间因移植肾新生肿瘤切除双肾1例、因复杂全身原因死亡1例、因间质性肺炎死亡1例,余15例受者双肾均存活者10例(中位随访59个月),单肾存活者5例(中位随访48个月)。移植1年时双肾存活组估算肾小球滤过率为(95±27)ml/(min·1.73 m2),显著高于单肾存活组(61±24)ml/(min·1.73 m2)(P<0.05),但3年时分别为(95±21)ml/(min·1.73 m2)和(69±31)ml/(min·1.73 m2),差异缩小,差异无显著统计学意义(P=0.12)。结论低龄婴儿双供肾移植虽然可以扩大供肾来源,但发生早期移植失败和单肾栓塞的风险较高。在单肾存活的情况下,受者仍具有相对满意的中-长期移植效果。  相似文献   
4.
Three patients with patent ductus arteriosus and moderate aortic stenosis had a marked reduction in aortic valve gradient following transcatheter ductal occlusion. The hemodynamic effects of an aortopulmonary shunt on the severity of left ventricular outflow obstruction and the implications on intervention are discussed.  相似文献   
5.
Quantitative measurement of left ventricular (LV) volumes, mass, and function is one of the most common and important indications for echocardiography. These measurements are among the most powerful tools for diagnosis and prognosis of congenital and acquired heart diseases and for assessment of medical, percutaneous, and surgical interventions. Awareness is also growing of the importance of right ventricular (RV) volume, mass, and function in many cardiopulmonary diseases. Furthermore, there are challenges and opportunities to measure the volume, mass, and function of complex chambers such as the left atrium, right atrium, and the univentricular heart. As echocardiography continues to be the imaging modality of choice for these measurements, the strengths and limitations of M‐mode, two‐dimensional (2D), and recently three‐dimensional (3D) echocardiographic (3DE) methodologies for accurate and reproducible measurement of these indices have been extensively investigated for congenital and acquired heart diseases. Evidence suggests that 3DE provides improved accuracy and reproducibility over 2D methods for measurement of LV volume and function calculation in adults and in children. Data have accumulated on the utility of 3DE for measuring chamber volumes and function for the RV and for the single ventricle, which may become more widely used in clinical and research arenas in the future. Finally, new advanced modes of analysis such as 3D strain and synchrony analysis by 3DE are promising methodologies that warrant further investigation.  相似文献   
6.
7.
8.
Curcumin (CRM) is a natural polyphenol with antioxidative, anti-inflammatory, and anticancer therapeutic properties. However, CRM therapeutic potential is limited by low water solubility and bioavailability. Intraliposomal remote loading describes the retention of drugs in liposome cores in response to transmembrane pH gradient. The current study describes for the first time the remote loading of CRM into liposomes using secondary (E-βCD) and tertiary (D-βCD) amino-modified β-cyclodextrins (βCDs) as carriers and solubilizers. βCDs were chemically modified to prepare the ionizable weak base functional group followed by forming a guest-host complex of CRM in the modified βCDs hydrophobic cavities via a solvent evaporation encapsulation technique. These complexes were then actively loaded into preformed liposomes, composed of DPPC/cholesterol (65/35 molar ratio) via pH gradient. The formation of CRM-βCDs inclusion complexes was characterized using UV-Vis spectroscopy, thermal analysis, and NMR spectroscopy. The complex stoichiometric ratio was determined to be 1 : 1 of CRM-βCDs based on Job''s plot which was also confirmed by the modified Benesi–Hildebrand equation with increasing probability of forming the 1 : 2 ratio of CRM-βCDs. The apparent formation constants (Kf) of 51.6, 100.9 and 55.4 mM−2 were determined for CRM-βCD, CRM-E-βCD, and CRM-D-βCD complexes, respectively. Liposome size, charge and polydispersity index indicate the presence of a homogeneous population before and after active loading. The encapsulation efficiencies of CRM-βCD complexes into pH gradient preformed liposomes were 16.5, 51.1, and 41.7 for CRM-βCD, CRM-E-βCD, and CRM-D-βCD, respectively, showing more than 5 fold increase compared to normal liposomes. The current study provides a novel remote loading approach utilizing chemically modified cyclodextrins to incorporate hydrophobic drugs into liposomes.

The current study provides a novel remote loading approach utilizing chemically modified cyclodextrins to incorporate hydrophobic drugs into liposomes.  相似文献   
9.
To present three rare mimics of primary angiitis of the central nervous system (PACNS). We describe 3 patients with rare diseases that can mimic PACNS at clinical presentation and neuroimaging. We describe the clinical course of these patients and also present a review of the literature regarding these three diagnoses. All 3 patients presented with neurological symptoms and had abnormal findings on neuroimaging suggestive of PACNS. After detailed history, careful review of systems, thorough laboratory workup and consideration of lack of a response to immunosuppressive therapy, PACNS was ruled out with identification of an alternative diagnosis. PACNS is a rare disease and a diagnostic challenge with many differentials. A thorough investigation and awareness of unusual disorders is critical in avoiding misdiagnosis.  相似文献   
10.
The neodymium/yttrium–aluminum–garnet (Nd/YAG) laser has been suggested to repair broken prostheses in the mouth. This study investigated the effects of different dentin thicknesses and air cooling on pulpal temperature rise during laser welding. Three intact human maxillary molars were prepared for full-veneer crown. For each tooth, dentin thicknesses in mesiobuccal cusp was 2, 3, or 4 mm. Twenty dies were duplicated from each of the prepared teeth. For metal copings with 0.5-mm thickness, wax patterns were prepared with dip wax technique directly onto each of dies. All patterns were sprued and invested. The castings were made using a nickel–chromium alloy (Nicromed Premium, Neodontics). A hole with 0.5-mm diameter was prepared on the mesiobuccal cusp of each crown. The Nd/YAG laser (9.85 W; 1 Hz repetition rate; fluence, 1.230 J/cm2; Fidelis Plus 3, Fotona) was used for welding with or without air cooling (n?=?10). The temperature rise was measured in pulpal chamber with a J-type thermocouple wire that was connected to a data logger. Differences between start and highest temperature reading were taken, and temperature rise values were compared using two-way analysis of variance and Tukey’s honestly significant difference tests (α?=?.05). Pulpal temperature rise varied significantly depending on the dentin thickness and air cooling (p?<?0.05). The non-air cooling group induced significantly the highest temperature increases. There were no significant differences between 2- and 3-mm dentin thicknesses groups (p?>?0.05); however, pulpal temperature rise was the lowest for 4-mm dentin thickness group (p?<?0.05). The highest values of thermal increase were found in the pulp chamber (6.8°C) when no air cooling was used in 2-mm dentin thickness group. Laser welding on base metal castings with Nd/YAG laser can be applied with air cooling to avoid temperature rises known to adversely affect pulpal health when dentin thickness is 2 or 3 mm.  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