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   235篇
  免费   14篇
儿科学   5篇
妇产科学   4篇
基础医学   39篇
口腔科学   1篇
临床医学   31篇
内科学   41篇
皮肤病学   3篇
神经病学   14篇
特种医学   20篇
外科学   44篇
综合类   3篇
预防医学   8篇
眼科学   8篇
药学   8篇
肿瘤学   20篇
  2023年   2篇
  2022年   6篇
  2021年   8篇
  2020年   6篇
  2019年   9篇
  2018年   8篇
  2017年   6篇
  2015年   4篇
  2014年   6篇
  2013年   5篇
  2012年   19篇
  2011年   8篇
  2010年   5篇
  2009年   2篇
  2008年   6篇
  2007年   7篇
  2006年   10篇
  2005年   13篇
  2004年   5篇
  2003年   7篇
  2002年   5篇
  2001年   1篇
  2000年   3篇
  1999年   5篇
  1997年   2篇
  1994年   1篇
  1992年   9篇
  1990年   7篇
  1989年   1篇
  1988年   1篇
  1987年   3篇
  1986年   3篇
  1985年   2篇
  1984年   2篇
  1983年   3篇
  1982年   3篇
  1980年   3篇
  1979年   6篇
  1978年   5篇
  1976年   2篇
  1975年   7篇
  1974年   6篇
  1973年   6篇
  1972年   4篇
  1971年   7篇
  1970年   2篇
  1969年   3篇
  1968年   1篇
  1967年   2篇
  1965年   1篇
排序方式: 共有249条查询结果,搜索用时 15 毫秒
91.
92.
In a randomized, prospective study, single-drug antibiotic therapy with cefoxitin (CFX) was compared to combination therapy with gentamicin and clindamycin (G/C) as definitive treatment for acute colonic diverticulitis. Excluding individuals requiring immediate operation, 51 patients with a clinical diagnosis of diverticulitis, who were hospitalized at five different medical centers, were randomized to receive CFX (30 patients) or G/C (21 patients). Age, sex, and the severity of diverticulitis were similar in the two groups. The cure rates of 90% and 85.7% observed for CFX and G/C, respectively, did not differ significantly. Leukocytosis resolved in a shorter time period in patients treated with CFX than in those treated with G/C (2.5 +/- 0.4 vs 4.1 +/- 0.6 days, respectively) (P = 0.03, Student's t test, unpaired data). Two cases of possibly antibiotic-related toxicity occurred in the CFX group versus three cases in the G/C group. The average cost of a course of CFX therapy was $417 compared with $488 for G/C. In this study, cefoxitin demonstrated efficacy and tolerability similar to that of gentamicin-clindamycin in the treatment of acute colonic diverticulitis and may be preferred in view of its narrower antimicrobial spectrum and lower cost.  相似文献   
93.
94.
OBJECTIVE: Nitric oxide is an important participant in septic shock. For example, it causes profound vasodilation and hypotension. Despite their potent antiinflammatory properties, glucocorticoids are not routinely used in septic shock. Some studies show that antiinflammatory doses of glucocorticoids can be beneficial, but other studies do not indicate their use in this situation. We have previously shown the inhibitory effect of nitric oxide on glucocorticoid receptor binding in vitro. Nitric oxide donors decreased the binding of immunoprecipitated glucocorticoid receptor obtained from mouse L929 fibroblasts. These in vitro findings prompted us to study whether in vivo manipulations of the nitric oxide system would interfere with the glucocorticoid receptor binding. DESIGN: Prospective, experimental study. SETTING: Research laboratory at a university. SUBJECTS: Female Wistar rats. INTERVENTIONS: Injection of bacterial lipopolysaccharide, anesthesia, cardiovascular perfusion, and organ removal for biochemical assays. MEASUREMENTS AND MAIN RESULTS: Following lipopolysaccharide injection, plasma nitrate + nitrite increased and inducible nitric oxide synthase activity was stimulated in several organs, the highest rates being in the lung and spleen. If dexamethasone was injected before lipopolysaccharide, it completely blocked inducible nitric oxide synthase induction and the increase in plasma nitrate + nitrite. On the other hand, if dexamethasone was injected after lipopolysaccharide, it failed to affect both inducible nitric oxide synthase induction and increased plasma nitrate + nitrite levels. Lipopolysaccharide also caused an inhibition of glucocorticoid receptor binding in lung and spleen. Previous administration of a nitric oxide synthase inhibitor prevented both lipopolysaccharide-induced decrease in glucocorticoid receptor binding and the increase in plasma nitrate + nitrite. Injection of a nitric oxide donor into naive animals significantly decreased glucocorticoid receptor binding activity and prevented dexamethasone-induced increase in liver tyrosine aminotransferase activity. CONCLUSIONS: The results indicate that the failure of glucocorticoids to exhibit their antiinflammatory effects when administered to endotoxemic rats may be explained, at least in part, by the nitric oxide-induced inhibition of glucocorticoid receptor binding ability, thus precluding the expression of the antiinflammatory effects of both exogenous and endogenous corticosteroids.  相似文献   
95.
96.
For several years, Virginia Tech and other schools have measured the frequency and severity of head impacts sustained by collegiate American football players in real time using the Head Impact Telemetry (HIT) System of helmet-mounted accelerometers. In this study, data from 37,128 head impacts collected at Virginia Tech during games from 2006 to 2010 were analyzed. Peak head acceleration exceeded 100 g in 516 impacts, and the Head Injury Criterion (HIC) exceeded 200 in 468 impacts. Four instrumented players in the dataset sustained a concussion. These data were used to develop risk curves for concussion as a function of peak head acceleration and HIC. The validity of this biomechanical approach was assessed using epidemiological data on concussion incidence from other sources. Two specific aspects of concussion incidence were addressed: the variation by player position, and the frequency of repeat concussions. The HIT System data indicated that linemen sustained the highest overall number of head impacts, while skill positions sustained a higher number of more severe head impacts (peak acceleration > 100 g or HIC > 200). When weighted using injury risk curves, the HIT System data predicted a higher incidence of concussion in skill positions compared to linemen at rates that were in strong agreement with the epidemiological literature (Pearson’s r = 0.72–0.87). The predicted rates of repeat concussions (21–39% over one season and 33–50% over five seasons) were somewhat higher than the ranges reported in the epidemiological literature. These analyses demonstrate that simple biomechanical parameters that can be measured by the HIT System possess a high level of power for predicting concussion.  相似文献   
97.
AIDS is the first international mass media disease. Throughout the world, most people have learned more about AIDS from radio, television and the press than from personal contacts with health professionals. Mass media AIDS materials influence behavior most when they are designed and developed for different segments of the audience, with the specific needs and concerns of those segments in mind. In the past mass media evoked fear, anxiety and other negative emotional responses to AIDS and didn't proposed practical and realistic ways of action. The journalists made frequently distinctions between innocent victims of HIV, that are infants and recipients of infected blood or blood products through health care, and other "guilty" infected people such as gays, sex workers or african people. Mass media can change behavior and if journalists accept their responsibility in presenting the news, the publicity about AIDS may have a great and positive impact in HIV/AIDS.  相似文献   
98.
99.
The intraoperative changes in extravascular lung water (EVLW) were studied in 40 patients undergoing aortic-coronary bypass grafting. The patients were divided into two groups on the basis of preoperative ejection fraction (EF) values (group I: EF greater than 45%; group II: EF less than 45%). EVLW was measured using the double-indicator dilution method (thermo/dye). In a control study, changes in transthoracic impedance (ZoTh) were recorded. The initial EVLW value in group I was 4.3 +/- 0.4 ml/kg body wt. and in group II, 4.4 +/- 0.3 ml/kg body wt. After extracorporeal circulation, significant changes in EVLW could be observed (group I: from 4.5 +/- 0.5 ml/kg body wt. to 7.0 +/- 0.2 ml/kg body wt.; group II: from 5.1 +/- 0.8 ml/kg body wt. to 7.8 +/- 0.9 ml/kg body wt. (p less than 0.001). At the end of the operation, no changes in EVLW were observed in group I. However, in group II EVLW was significantly different to initial values (6.3 +/- 1.0 ml/kg body wt., p less than 0.01). The results obtained using the double-indicator method were identical with those obtained using the transthoracic impedance method. A marked correlation could be seen between length of ECC recording and EVLW values at the end of the operation, especially when the ECC time was 90 min or more (r = 0.84). Based on our results, it must be assumed that intraoperative damage to capillary membranes occurs if the ECC time is above 90 min.  相似文献   
100.
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