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   22篇
  免费   0篇
  国内免费   1篇
儿科学   1篇
临床医学   1篇
内科学   2篇
特种医学   2篇
外科学   9篇
预防医学   6篇
药学   1篇
肿瘤学   1篇
  2015年   2篇
  2011年   4篇
  2010年   1篇
  2007年   2篇
  2006年   1篇
  2005年   1篇
  2004年   3篇
  2003年   1篇
  2002年   1篇
  1999年   1篇
  1998年   1篇
  1979年   1篇
  1970年   1篇
  1969年   2篇
  1962年   1篇
排序方式: 共有23条查询结果,搜索用时 15 毫秒
1.
2.
Both trauma-associated and medical emergency situations in children are often associated with significant pain. Therefore, appropriate pain management is an important clinical issue for emergency medical services (EMS). A number of authors have also documented that children pose significant cognitive and therapeutic challenges for EMS providers. For example, routes of administration, drug dosing, and perceived discomfort with the care of an injured child are all barriers to administration of analgesia in children. A noninvasive route, e.g. rectal or intranasal, is a promising alternative in emergency situations until an intravenous line is achieved. For the intravenous use of analgesics, ketamine, midazolam, and various opioids are available.  相似文献   
3.
BACKGROUND: Tracheomalacia is associated with esophageal atresia (EA), but may go unnoticed from external splinting forces. Intra-operative dissection with fistula division releases external splinting, revealing tracheomalacia only post-operatively. Analysis of surgical technique may disclose an iatrogenic etiology. METHODS: From 1995 - 2004, 44 neonates underwent surgery for EA. All patients underwent pre-, intra- and postoperative bronchoscopy. Operative and bronchoscopic notes were studied for malacia, and extensive dissection of the esophagus and fistula from the trachea. RESULTS: Surgical mortality was 6.8 %. Pre-operative tracheomalacia was diagnosed in 3 patients, who eventually fared well. In 17 other patients, the pre-operative bronchoscopy was negative, but airway obstruction developed post-operatively. Tracheomalacia was documented at the site of the former fistula and surgical release maneuvers. Aortopexy was required in 5 instances, whereas 12 others with malacia were managed conservatively. CONCLUSIONS: Mediastinal connective tissue and the fistula may splint open the marginally diseased airway in patients with EA, the lack of which may disclose previously unknown tracheomalacia after repair. When aggressive release maneuvers have been required, early aortopexy may be preferred to ventilator dependency.  相似文献   
4.

Organophosphate pesticides (OPs), in particular diazinon and chlorpyrifos, have frequently been detected in toxic concentrations in waterways draining agricultural and urban areas in California’s Sacramento and San Joaquin River watersheds (US Geological Survey 1997, Werner et al. 2000). Toxicity has in part been linked to stormwater runoff of OP pesticides applied during the dormant season on stonefruit and almond orchards (Foe and Sheipline 1993; Kuivila and Foe 1995). State Water Quality Plans have now been implemented by regulatory agencies to prevent movement of OPs into surface water, and growers have reduced the application of OPs. Simultaneously, the use of so-called reduced-risk alternatives, such as pyrethroid insecticides and Bacillus thuringiensis bloom sprays, has increased dramatically (Epstein et al. 2000).

Best management practices (BMPs) are aimed at reducing off-site movement of pesticides into surface waters. Pyrethroid pesticides, among them the widely used esfenvalerate (Asana®) are considerably more hydrophobic (solubility in water: 0.4 μg/L) than the relatively soluble OP pesticide diazinon (solubility in water: 40,000 μg/L; Extoxnet 2001). Although runoff of pyrethroids is believed to be minimal thus reducing pesticide impact on surface waters, esfenvalerate has been shown to be toxic to fish at extremely low concentrations (≤ 1 ug/L; Haya 1989; Clark et al. 1989; Lozano et al. 1992), and potentially poses a significantly higher risk to these organisms than OP pesticides. In addition, its potential to bioaccumulate and bioconcentrate is high (Smith and Stratton 1986). A second recommended method for reducing toxic runoff from orchards is the use of different orchard floor cover crops. Cover crops are believed to enhance water infiltration (Hargrove 1991).

This study was performed to measure the effectiveness of these two BMPs in reducing the toxicity of Stormwater runoff. Experiments were carried out in a French prune orchard at the Talbot-Vereschagin Ranch, Glenn County, California.

  相似文献   
5.
BACKGROUND: Fiberoptic tracheoscopy assisted repair of tracheoesophageal fistula (TARTEF) has been reported to be useful for the surgeon with regards to identification of the fistula and proper fistula ligation. The aim of this article is to report our 10-year experience using TARTEF with intermittent positive pressure ventilation (IPPV) during tracheoesophageal fistula (TEF) repair in newborns. METHODS: With ethical committee approval, we included all patients undergoing TARTEF from 1995-2005. Variables of interest were (1) respiratory deterioration caused by gastric inflation because of IPPV during surgery and endoscopy; (2) detection of additional airway anomalies; (3) success of intubation of the fistula; (4) other side effects or adverse events. Data are given in median and range. RESULTS: Forty-seven neonates with TARTEF were included. Mean gestational age was 37 weeks (31-42) and mean weight was 2.5 kg (1.1-3.8). The patients were intubated with tracheal tubes size 2.5-3.5 mm ID. Appropriately sized fiberoptic bronchoscopes with an outer diameter of 2.0, 2.4 and 2.8 mm were used; passed through the lumen of the tracheal tube (TT) thereby requiring the use of IPPV to ensure adequate ventilation. No respiratory deterioration was noted as a consequence of intraoperative fiberoptic manipulation within the trachea or because of gastric hyperinflation with IPPV. In all patients, the TEF was successfully penetrated with the fiberscope and this clearly helped the surgeon to rapidly identify and dissect the fistula. In two patients a tracheal bronchus was identified. In two patients accidental extubation occurred during endoscopic confirmation of successful fistula repair. CONCLUSIONS: While fiberoptic TARTEF through the tracheal tube with IPPV did expedite and facilitate surgery, it did not cause clinically relevant impairment of ventilation. Careful manipulation during fiberoptic assessment is required to avoid tube displacement.  相似文献   
6.
California (USA) agriculture employs pyrethroid and organophosphate insecticides to control insects in orchards and other crops. Diazinon and esfenvalerate were selected for this study because of their application overlaps. Toxicological and biochemical responses of larval fathead minnows (Pimephales promelas) exposed singly and in combinations to esfenvalerate and diazinon were determined. Exposures were 96-h static renewal tests that used standard U.S. Environmental Protection Agency acute toxicity test methods. After pesticide exposures, larvae were evaluated for carboxylesterase and acetylcholinesterase activity, and histopathological effects. Carboxylesterase activity was examined because of its potential influence on the toxicity of both organophosphates and pyrethroids. In vivo studies demonstrated that diazinon significantly inhibited carboxylesterase activity at nominal water concentrations as low as 50 microg/L. However, esfenvalerate did not affect carboxylesterase activity at any concentration tested. Liver glycogen depletion was the only histopathological effect observed; this effect was demonstrated with the individual pesticides and pesticide combinations (i.e., mixtures). The combinations of diazinon and esfenvalerate causing acute toxicity to fathead minnow larvae appeared to be greater than additive (i.e., synergistic) in all three tests.  相似文献   
7.
Background: The effect of vasoconstrictors on intracerebral hemodynamics in anesthetized patients is controversial. The influence of phenylephrine and norepinephrine on the cerebral circulation was investigated in isoflurane- or propofol-anesthetized patients using transcranial Doppler ultrasonography.

Methods: Forty patients were randomly assigned to have vasoconstrictor tests with norepinephrine or phenylephrine during either isoflurane or propofol anesthesia. Blood flow velocities were simultaneously measured in the middle cerebral artery and ipsilateral extracranial internal carotid artery. Baseline recordings were done during stable anesthesia in a supine position (test 0). A second series of measurements were performed after norepinephrine or phenylephrine had increased mean arterial blood pressure by about 20% (test 1). With maintained norepinephrine or phenylephrine infusion, a final series of results were obtained after the increased mean arterial blood pressure was counteracted by a slightly head-up patient position (test 2).

Results: Both vasoconstrictors significantly increased mean flow velocities in the middle cerebral artery (norepinephrine: 43 +/- 11 cm/s to 49 +/- 11 cm/s; phenylephrine: 43 +/- 8 cm/s to 48 +/- 9 cm/s; +/- SD) and internal carotid artery (norepinephrine: 27 +/- 7 cm/s to 31 +/- 8 cm/s; phenylephrine: 27 +/- 9 cm/s to 31 +/- 10 cm/s) in the isoflurane-but not in the propofol-anesthetized patients. In the head-up position, only small and insignificant flow velocity changes were observed in both cerebral arteries independent of the vasoconstrictor or background anesthetic.  相似文献   

8.

Objective

To evaluate the possible relationship between industrial air pollution and oxidative stress in schoolchildren by comparing parameters from children residing in two nearby localities with contrasting environmental conditions.

Participants

42 schoolchildren (12–15 years) from Pancevo (site of Serbia’s largest petrochemical installation) formed the exposed group. 82 schoolchildren from Kovacica village, located 30 km north of Pancevo, formed the non-exposed group.

Methods

Oxidative stress status, anti-oxidative defense parameters, paraoxonase-1 status, lipid status, glucose concentration and leukocyte counts were compared in two groups.

Results

The children from Pancevo showed higher level of oxidative stress demonstrated by an elevated malondialdehyde concentration (P <0.001) and decreased superoxide dismutase activity (P<0.01) in comparison to the non-exposed group.

Conclusions

The results suggested a relationship between the presence of air pollutants and increased oxidative stress in schoolchildren residing in an industrial environment.  相似文献   
9.
Effluents from Walker Mine and its tailings pile have resulted in toxic concentrations of metals in Dolly and Little Grizzly Creeks. Recent remedial structures have greatly reduced metal loading, however the need to assess recovery of the receiving aquatic ecosystem exists so that future remediation priorities can be established. The objective was to contribute to this assessment using Toxicity Identification Evaluation procedures. Water samples were collected at several sites in Dolly and Little Grizzly Creeks. Untreated samples and samples passed through ion exchange columns, which remove cationic metals, were compared in side-by-side bioassays using Pimephales promelas, Ceriodaphnia dubia, and Selenastrum capricornutum. Samples were analyzed for total and dissolved copper, cadmium, zinc, and iron. Copper was the element responsible for toxicity. Toxicity was detected in the mine discharge and immediately downstream from the tailings where dissolved copper concentrations were 250 μg/L and 415 μg/L, respectively. Toxicity decreased at downstream sites but extended at least 6.4 km downstream. Improvement in bioassay performance by the treated waters verified metal toxicity. The results indicate that the mine effluent and tailings pile currently have the heaviest impact on Dolly and Little Grizzly Creeks and should be given the highest priority in future remedial programs. Received: 16 January 1998/Accepted: 10 July 1998  相似文献   
10.
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