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   297篇
  免费   50篇
  国内免费   2篇
耳鼻咽喉   8篇
儿科学   15篇
妇产科学   3篇
基础医学   35篇
口腔科学   10篇
临床医学   38篇
内科学   66篇
皮肤病学   10篇
神经病学   22篇
特种医学   65篇
外科学   40篇
综合类   3篇
预防医学   7篇
眼科学   5篇
药学   5篇
中国医学   1篇
肿瘤学   16篇
  2024年   2篇
  2023年   13篇
  2022年   2篇
  2021年   9篇
  2020年   5篇
  2019年   2篇
  2018年   8篇
  2017年   12篇
  2016年   12篇
  2015年   10篇
  2014年   15篇
  2013年   20篇
  2012年   7篇
  2011年   5篇
  2010年   11篇
  2009年   22篇
  2008年   9篇
  2007年   7篇
  2006年   4篇
  2005年   4篇
  2004年   1篇
  2003年   6篇
  2002年   2篇
  2001年   8篇
  2000年   5篇
  1999年   6篇
  1998年   15篇
  1997年   13篇
  1996年   14篇
  1995年   5篇
  1994年   10篇
  1993年   7篇
  1992年   1篇
  1991年   2篇
  1990年   6篇
  1989年   11篇
  1988年   8篇
  1987年   3篇
  1986年   9篇
  1985年   7篇
  1984年   5篇
  1983年   4篇
  1982年   4篇
  1980年   3篇
  1979年   1篇
  1978年   5篇
  1977年   3篇
  1976年   5篇
  1975年   1篇
排序方式: 共有349条查询结果,搜索用时 171 毫秒
31.
OBJECTIVE: To characterize the acute clinical course and economic burden of nonpolio enteroviral (NPEV) illness in the summer/fall season as seen in private pediatric practice. METHODS: We prospectively studied 380 children aged 4 to 18 years with systemic NPEV syndromes presenting to private suburban pediatric practices. Seventy-three asymptomatic controls were concurrently enrolled. Clinical diagnosis of NPEV illness was based on the presence of fever plus at least one of the following: headache and stiff neck (n = 2); myalgia and malaise (n = 105); nonpuritic maculopapular rash (n = 10); papulovesicular stomatitis (n = 214); papular rash of the hands, feet, and mouth (H/F/M) (n = 30); or pleurodynia (n = 11). Study participants were enrolled during a 4-month time span (July-October, 1994) and followed daily for 14 days. A parent symptom diary card and twice weekly phone contacts by study nurses characterized the illness to include the frequency of health care contacts, the necessity for laboratory tests, medication use, and school/work absenteeism. RESULTS: Three hundred seventy-two (98%) children completed the study; 122 (33%) of the patients were confirmed to be infected with NPEV. Confirmed NPEV infection was more frequently observed in Rochester, NY (85/147 = 58%) than in Scottsdale, AZ (32/224 = 14%). The age group 4 to 12 years comprised 79% to 90% of the enrollees, depending on the syndrome. Median duration of illness and median number of missed days of school/summer camp/work for the enrolled patients was: meningitis (7 days ill, 2 days missed), myalgia/malaise (9 days ill, 3 days missed), rash (6 days ill, 4 days missed), stomatitis (7 days ill, 2 days missed), H/F/M (7 days ill, 1 day missed), and pleurodynia (8 days ill, 3 days missed). Direct medical costs varied from $69 per case to $771 per case and indirect costs, attributable primarily to parent missed work and/or sick-child care, varied from $63 per case to $422 per case for H/F/M and meningitis, respectively. In households, H/F/M spread to 50% of siblings and 25% of parents. CONCLUSIONS: In our study population, NPEV infection: 1) caused sufficient illness to prompt physician visits in summer and fall; 2) occurred more frequently in 4 to 12 year olds than in adolescents; 3) produced various clinical syndromes concurrently during the same months in the same season of a given year; 4) varied in occurrence geographically; 5) was characterized by numerous symptoms of longer duration than previously recognized; and 6) produced a significant economic impact by generating both direct and indirect costs.  相似文献   
32.
33.
Purpose: To retrospectively examine the optic disc photographs of a glaucoma population for optic disc haemorrhages, vascular occlusions and vascular abnormalities. Methods: The optic disc photographs of 906 eyes of glaucoma and suspect glaucoma patients were examined. Optic disc photographs were taken annually, where possible, with the follow-up period varying between 1 and 14 years duration (mean, 2.89). Glaucoma patients are regularly reviewed every 4–6 months and glaucoma suspects every 1–2 years, depending on the ophthalmologist. Low-tension glaucoma patients were reviewed more frequently (mean, every 2.6 months). The results of the findings were compared to a control group of 39 subjects with a mean follow-up period of 7 years, using Fisher's exact test. Results: It was found that during the period under review, 7.4% (n= 67) of eyes had optic disc haemorrhages. The highest frequency of optic disc haemorrhages (37.5%) was found in the low tension glaucoma group (P= 0.0001) followed by 11.4% of primary open-angle glaucoma eyes (P= 0.03). In the normal group there were three eyes with optic disc haemorrhages and one with a disc collateral, which constitutes 5.1% vascular changes in this sub-group. Of the study eyes 2.8% had central retinal vein occlusions, 1.3% branch vein occlusion, 1.2% disc vessel abnormalities (loops) and 1.1% disc collaterals. Discrete nerve fibre layer haemorrhages and microaneurysms were found in 0.8% and 1.8% of eyes, respectively. Conclusions: A total of 16.8% of the eyes observed in this study had either disc haemorrhages or vascular changes. The underlying trend of vascular and haemorrhagic changes in glaucoma are demonstrated in this sample, which is in general agreement with previous studies. The high percentage of optic disc haemorrhages in low tension glaucoma is highlighted. The presence of microaneurysms and nerve fibre layer haemorrhages is interesting but of unknown significance.  相似文献   
34.
35.
36.
Mitropoulos  KA; Martin  JC; Reeves  BE; Esnouf  MP 《Blood》1989,73(6):1525-1533
The endogenous, negatively charged surface that induces activation of the contact coagulation factors was investigated in plasmas taken from women in late pregnancy and control subjects of child-bearing age. The plasmas from the two groups of subjects were incubated at 4 degrees C for 24 hours either in plastic or in glass tubes and the factor VII coagulant activity (VIIc) was assayed in the treated plasmas. The activation of factor VII under these conditions involves the generation of enzymes derived from factor XII (XIIa). The contact surface is rate- limiting for the activation of factor VII in the plasmas in both groups of subjects and can be supplemented by large multilamellar liposomal vesicles carrying the appropriate density of negative charge. The size of these vesicles is within the range of sizes of the large lipoprotein particles (chylomicrons, very low and intermediate-density lipoproteins). The relationship between the density of negative charge on the liposomal vesicles and VIIc was similar in the late pregnancy and the control plasmas incubated in plastic tubes. At a saturating density of negative charge the observed relative VIIc was similar in both sets of plasmas. The incubation of late pregnancy or control plasma in plastic tubes in the presence of sodium stearate caused VIIc to increase with increasing concentration of the added fatty acid. These results suggest that large lipoprotein particles carrying the appropriate free fatty acid at a sufficient density of negative charge could provide the contact surface that induces the generation of factor XIIa and the subsequent activation of factor VII. Moreover, plasmas from women in late pregnancy have a higher concentration of potential surface and a higher density of negative charge than the plasmas from nonpregnant women.  相似文献   
37.
38.
39.
This study examined the use of cutaneous reactive hyperemia as a means for noninvasive assessment of wound severity of newly formed temperature-modulated pressure injuries in a porcine model. Two methods to quantify the extent of the reactive hyperemic reflex were developed. First, color image analysis was used to measure the hue of injured tissue. The specific hue of the skin surface of the wounded site was found to provide an indication of the severity of the wounds. Second, infrared imaging, coupled with computer image processing, was used to detect differences in skin temperature. The relative surface temperature of the wounds showed a strong correlation with the presence or absence of deep tissue injury. Both techniques correlated with the severity of the injuries as determined by a histologic assessment of biopsied tissue, but infrared imaging provided the better means to assess wound depth.  相似文献   
40.
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