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   306篇
  免费   28篇
  国内免费   13篇
儿科学   13篇
妇产科学   2篇
基础医学   33篇
口腔科学   5篇
临床医学   74篇
内科学   67篇
皮肤病学   2篇
神经病学   9篇
特种医学   81篇
外科学   12篇
综合类   2篇
预防医学   12篇
眼科学   2篇
药学   17篇
中国医学   1篇
肿瘤学   15篇
  2020年   2篇
  2019年   4篇
  2018年   2篇
  2017年   7篇
  2016年   2篇
  2015年   2篇
  2014年   3篇
  2013年   9篇
  2012年   5篇
  2011年   11篇
  2010年   8篇
  2009年   4篇
  2008年   4篇
  2007年   13篇
  2006年   6篇
  2005年   11篇
  2004年   1篇
  2003年   3篇
  2002年   8篇
  2001年   6篇
  2000年   6篇
  1999年   10篇
  1998年   22篇
  1997年   20篇
  1996年   17篇
  1995年   14篇
  1994年   11篇
  1993年   10篇
  1991年   1篇
  1990年   5篇
  1989年   15篇
  1988年   21篇
  1987年   9篇
  1986年   9篇
  1985年   4篇
  1984年   6篇
  1983年   4篇
  1982年   13篇
  1981年   5篇
  1980年   6篇
  1979年   4篇
  1978年   3篇
  1977年   8篇
  1976年   6篇
  1975年   5篇
  1973年   1篇
  1909年   1篇
排序方式: 共有347条查询结果,搜索用时 15 毫秒
11.
12.
Feeding problems in young PKU children   总被引:3,自引:0,他引:3  
Behavioural feeding problems were found to be more prevalent in a group of 15 PKU children aged 1-5 years when compared to non-PKU controls. The parents of PKU children identified poorer appetites ( p < 0.01), a more limited range of foods consumed ( p < 0.03) and more gastrointestinal symptoms such as vomiting and constipation ( p < 0.03) than control children. The children were slower to feed ( p < 0.03), were more likely to dislike sweet foods and some ate separately from the rest of the family at mealtime ( p < 0.03). The effects on normal feeding behaviour should be considered when advocating strict diet therapy for young PKU children.  相似文献   
13.
14.
The objective of this study was to derive a simple equation to convert distances between air miles traveled by a helicopter and ground miles traveled by an ambulance. We performed a retrospective analysis of a convenience sampling of 245 "lights and sirens" ground ambulance transports between 1993 and 1997. Ground distances were recorded from odometer miles for each transport. Air miles were calculated using the Global Positioning System (GPS), measuring the distance in a straight line from the scene to the hospital. Air and ground distances were entered into a computerized spreadsheet, and the correlation coefficient and regression equation were derived. A simple approximation equation was developed and compared against the derived regression equation. There was a strong linear correlation between ground miles and air miles at virtually all distances studied (R = 0.932, R(2) = 0.869). Regression analysis revealed the following relationship: Ground miles = 0.94 + 1.25 (air miles). This was simplified to an approximation of: Ground miles = 1.3 (air miles). The approximation equation yielded an answer within 1 mile of the regression equation for distances up to 40 air miles. It is concluded that in a mixed rural and urban EMS system, one may convert air and ground mileage estimates by using the simple relationship: Ground miles = 1.3 (air miles). This conversion coefficient may prove useful for EMS personnel in designing reasonable helicopter utilization policies, making accurate transport decisions and conducting research.  相似文献   
15.
To determine the accuracy of the Esophageal Detector Bulb (EDB) in the aeromedical setting, we conducted a prospective, observational study of all intubated patients transported by an aeromedical program over two years. Flight personnel recorded the results of the EDB, clinical examination, pulse oximetry, and capnography (ETCO(2)). Endotracheal tube position was confirmed by prehospital ETCO(2) or by the receiving emergency physician. There were 104 EDB assessments in 53 patients. The EDB correctly identified four of five esophageal intubations and 96 of 99 tracheal intubations. The sensitivity and specificity of the EDB in the detection of an esophageal intubation were 80% (95% CI, 38-96%) and 97% (95% CI, 92-99%), respectively, and the overall accuracy was 96% (95% CI, 90-98%). The EDB augments the ability of an aeromedical crew to determine endotracheal tube position, but its results must be carefully interpreted in the context of other available means of confirmation of endotracheal tube position.  相似文献   
16.
BACKGROUND: An infection control problem in dental operatories which is not fully controlled is waterline contamination by heterotrophic mesophilic bacteria. These bacteria are present in water supplies as a planktonic phase and adhere to the lumen of tubings as a biofilm comprised of their external cell surface glycocalyx and by production of extracellular carbohydrate polymers. The adherent film is most difficult to remove. The accumulated planktonic phase can be reduced significantly by flushing water from the lines before use in patient treatment, but will return when the equipment is idle through the accumulation of more planktonic phase and by slough of the biofilm surface-adsorbed phase not yet enmeshed in the carbohydrate matrix. Chlorine dioxide has antimicrobial activity against many bacteria, spores, and viruses. It is used in water supply treatment as a disinfectant and slime preventive and has an advantage over chlorine in that carcinogenic trihalomethanes are not generated. METHODS: This study compared use of phosphate buffer-stabilized chlorine dioxide (0.1%) mouthrinse as a lavage in ultrasonic dental scaler units with the use of tap water as a control. Sterile water flushed through the units onto heterotrophic plate count (HPC) sampler plates was cultured 7 days at room temperature and colonies were counted at 12x. One test and one control unit were used for biopsy of internal tubing and scanning electron microscopy imaging. RESULTS: The HPC counts, in colony forming units (CFU)/ml, were reduced 3- to 5-fold by flushing tap water through the units, but they returned after units were idle overnight. When phosphate-buffered chlorine dioxide mouthrinse was used as a lavage, CFU/ml were reduced 12- to 20-fold. Holding chlorine dioxide in waterlines overnight reduced recurrent buildup compared to water (P <0.05). Scanning electron microscopy images indicated a significant reduction of biofilm coverage by chlorine dioxide as compared to water (P<0.001). CONCLUSIONS: Phosphate-buffered chlorine dioxide mouthrinse was effective in these short-term trials for control of waterline contamination in ultrasonic dental scaling units. It should prove as useful in dental professional waterline applications as it has in industrial uses for biofilm control.  相似文献   
17.
目的快速鉴定血培养中的金黄色葡萄球菌和凝固酶阴性葡萄球菌(CoNS),结合临床快速判定是否为污染菌。方法采用荧光原位杂交法鉴定血培养中的金黄色葡萄球菌和CoNS,杂交结果若为CoNS,根据临床资料进行判断,并与文献推荐的污染判断法进行结果比较。结果探针的特异性经由标准菌株和临床分离菌株证实。金黄色葡萄球菌探针的特异性和敏感性均为100%,GoNS探针的特异性和敏感性分别为100%和95.5%。179株CoNS中117株判断为污染菌,污染率为68%,与文献推荐的污染判断方法一致。结论荧光原位杂交法适用于血培养中的金黄色葡萄球菌和CoNS的快速鉴定,以排除CoNS污染。  相似文献   
18.
A multicenter clinical study was conducted using iohexol, a second-generation nonionic contrast medium, for excretory urography performed in 130 children. Doses of iohexol (300 mg iodine/ml) ranged between 150 and 660 mgI/kg (0.5 and 2.2 ml/kg). Iohexol was tolerated well, and no significant adverse reactions occurred. Sixty-five iohexol urograms were evaluated to determine the minimum dose for adequate visualization of the kidneys and collecting systems. A dose greater than 300 mgI/kg (1.0 ml/kg) always resulted in a urogram of diagnostic quality, while visualization was insufficient for diagnosis in 10% of studies done with doses of 150-300 mgI/kg (0.5-1.0 ml/kg). Another 65 iohexol urograms were compared in a blinded manner with a similar number of studies performed using iothalamate meglumine at comparable iodine concentration and dose. Visualization of calyces and pelvoinfundibular structures achieved with iohexol was rated better with statistical significance, but there was no difference in visualization of the renal parenchyma or ureters. Use of iohexol in excretory urography may be advantageous in children who are at greatest risk for an adverse reaction to contrast media or in those most likely to benefit from use of a low osmolality contrast agent.  相似文献   
19.
Interobserver variation in the interpretation of abdominal radiographs   总被引:2,自引:0,他引:2  
A total of 140 sets of abdominal radiographs were reviewed independently by four qualified diagnostic radiologists. The degree of interobserver agreement was determined by calculating kappa values for 19 commonly used radiographic signs and diagnoses. There was fair to excellent interobserver agreement for 11 signs and diagnoses and poor agreement for the remaining eight. The signs and diagnoses for which agreement is poor cannot be considered reliable and include particularly large bowel obstruction and nonspecific gas pattern.  相似文献   
20.
Knee injuries: high-resolution MR imaging   总被引:5,自引:0,他引:5  
Gallimore  GW  Jr; Harms  SE 《Radiology》1986,160(2):457-461
Recent technologic advances have made high-resolution magnetic resonance (MR) imaging of the knee a clinical reality. Ten healthy volunteers and 30 patients with suspected knee injuries were imaged using receive-only surface coils and two-dimensional multisection or three-dimensional selective acquisition techniques. Arthroscopic and/or surgical correlation was available in 15 patients. Tears of the cruciate ligament, medial collateral ligament, and meniscus are illustrated. Nonorthogonal views of the anterior cruciate ligament are useful for demonstrating both femoral and tibial attachments in the same section. The posterior cruciate ligament is usually well seen on sagittal views. T2-weighted images are helpful for demonstrating collateral ligament tears and meniscal tears when joint effusion is present. Thin sections (1-5 mm) are necessary to define many meniscal and cruciate tears. High-resolution, thin-section MR imaging can be used to diagnose soft-tissue injuries of the knee and has the potential to become a major imaging method in the evaluation of knee injuries.  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