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   525篇
  免费   40篇
  国内免费   12篇
耳鼻咽喉   1篇
儿科学   13篇
妇产科学   8篇
基础医学   49篇
口腔科学   25篇
临床医学   68篇
内科学   208篇
皮肤病学   3篇
神经病学   10篇
特种医学   74篇
外科学   22篇
综合类   24篇
预防医学   36篇
眼科学   1篇
药学   22篇
中国医学   1篇
肿瘤学   12篇
  2023年   4篇
  2022年   4篇
  2021年   5篇
  2020年   5篇
  2019年   6篇
  2018年   11篇
  2017年   4篇
  2016年   11篇
  2015年   7篇
  2014年   10篇
  2013年   16篇
  2012年   6篇
  2011年   10篇
  2010年   17篇
  2009年   26篇
  2008年   9篇
  2007年   26篇
  2006年   16篇
  2005年   14篇
  2004年   24篇
  2003年   19篇
  2002年   12篇
  2001年   15篇
  2000年   9篇
  1999年   10篇
  1998年   33篇
  1997年   33篇
  1996年   30篇
  1995年   25篇
  1994年   20篇
  1993年   19篇
  1992年   9篇
  1991年   5篇
  1990年   13篇
  1989年   14篇
  1988年   21篇
  1987年   21篇
  1986年   9篇
  1985年   6篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1981年   2篇
  1980年   3篇
  1979年   1篇
  1978年   1篇
  1977年   5篇
  1976年   3篇
  1975年   3篇
排序方式: 共有577条查询结果,搜索用时 15 毫秒
11.
Evolutionary silencing of the human elastase I gene (ELA1)   总被引:6,自引:0,他引:6  
  相似文献   
12.
PurposeWe aimed to assess the prognostic value of Neutrophil to Lymphocyte Ratio (NLR) on long-term outcomes and graft dysfunction after lung transplantation.MethodsWe retrospectively reviewed all patients receiving a lung transplant at our institution from 2011 to 2014. The primary exposure was elevated NLR at the time of transplant, defined by NLR>4. The primary outcomes were graft failure and three-year all-cause mortality. Multivariate logistic regression and Kaplan-Meier survival analysis were used to analyze outcomes.Results95 patients were included. 40 patients (42%) had an elevated NLR. Elevated NLR was associated with graft failure (OR: 4.7 [1.2–18.8], p = 0.02), and three-year mortality (OR: 5.4 [1.3–23.2], p = 0.03) on multivariate logistic regression. Patients with elevated NLR demonstrated significantly lower survival on Kaplan-Meier analysis (50% versus 74%, p = 0.02). The c-statistic for our multivariate model was 0.91.ConclusionElevated neutrophil to lymphocyte ratio is associated with poor long-term survival and graft failure after lung transplantation.  相似文献   
13.
OBJECTIVE: To compare the effectiveness of three new topical anesthetics that do not contain cocaine (prilocaine-phenylephrine, tetracaine-phenylephrine [tetraphen], and tetracaine-lidocaine-phenylephrine) to that of tetracaine-adrenaline-cocaine (TAC) during laceration repair in children. DESIGN: Prospective, randomized, double-blind clinical trial. SETTING: The emergency department of an urban children's hospital. PARTICIPANTS: Children 1 year of age or older with a laceration /= 5 years of age using a visual analogue scale (VAS). Suture technicians, research assistants, and parents also scored pain using a seven-point Likert scale. In addition, suture technicians completed an anesthetic effectiveness scale. RESULTS: There was consistently no difference demonstrated between the effectiveness of tetraphen and that of TAC for each outcome measure of each observer group. A statistically significant difference was seen among anesthetics when comparing VAS and Likert scale scores of suture technicians and Likert scale scores of research assistants. Based on post hoc analyses, these statistically significant differences were between TAC and prilocaine-phenylephrine (suture technician VAS and Likert scale) and between TAC and tetracaine-lidocaine-phenyl-ephrine (suture technician Likert scale), but not between TAC and tetraphen. When power analyses were performed using alpha = 0.05 and beta = 0.20, it was possible to detect a difference of 1.2 VAS units for each of the observer groups. Based on anesthetic effectiveness scale scores, the three new topical preparations collectively performed significantly better on the face and scalp than on the extremities (relative risk = 1.83; 95% confidence interval 1.20 < relative risk < 2.79). CONCLUSION: This study demonstrated the effectiveness and safety of three new non-cocaine-containing topical anesthetics. Consistently, there was no statistical difference demonstrated between the effectiveness of tetraphen and that of TAC for each outcome measure of each observer group. Tetraphen offers an effective alternative to TAC during laceration repair in children.  相似文献   
14.
Non-typhoid Salmonella gastroenteritis   总被引:2,自引:0,他引:2  
  相似文献   
15.
PURPOSE: We hypothesized that obese adults with coronary heart disease, obstructive lung disease, or depression would report greater impairments in health-related quality of life owing to their angina, dyspnea, or depressive symptoms as compared with persons with normal body weight. METHODS: We analyzed cross-sectional data from the Ambulatory Care Quality Improvement Project, a multicenter study of veterans enrolled in general internal medicine clinics. Health-related quality of life was assessed using the Medical Outcomes Study Short Form-36, the Seattle Angina Questionnaire, the Seattle Obstructive Lung Disease Questionnaire, and the Hopkins Symptom Checklist for Depression. RESULTS: Compared with patients of normal weight (body mass index: 18.5 to 24.9 kg/m2), underweight patients (body mass index <18.5 kg/m2) reported health-related quality-of-life scores that were at least 5% lower (worse) in all 15 quality-of-life domains examined. Patients with class III obesity (body mass index > or =40 kg/m2) reported quality-of-life scores that were at least 5% lower than those of normal weight patients in eight domains. Scores of overweight patients (body mass index: 25 to 29.9 kg/m2) were higher (better) than those of normal weight patients in 11 domains. CONCLUSION: Body mass index was strongly associated with generic- and condition-specific health-related quality of life. Our results suggest that, when considering health-related quality-of-life outcomes among veterans, the optimal body mass index may be above the "normal" range. Further research should test the validity of the 1998 National Institutes of Health body mass index categories as predictors of health outcomes among veterans.  相似文献   
16.
Hafenrichter  DG; Wu  X; Rettinger  SD; Kennedy  SC; Flye  MW; Ponder  KP 《Blood》1994,84(10):3394-3404
Hepatic gene therapy could be used to treat a number of inherited blood diseases such as hemophilia or thrombophilia. Although liver-directed retroviral transduction can result in long-term gene expression in vivo, the low level of protein production has limited its clinical application. We reasoned that the insertion of liver-specific promoters into retroviral vectors would increase gene expression in vivo. The 347- bp human alpha 1-antitrypsin (hAAT), the 810-bp murine albumin (mAIb), the 490-bp rat phosphoenolpyruvate carboxykinase (rPECK), and the 596- bp rat liver fatty acid binding protein promoters were inserted into a Moloney murine leukemia retroviral backbone containing the hAAT reporter gene. Vectors that produced appropriately sized RNA and hAAT protein in vitro were tested in vivo by transducing regenerating rat livers. Long-term serum expression of the hAAT reporter gene was normalized to retroviral transduction efficiency as determined by using a polymerase chain reaction-based assay of genomic DNA from transduced rat livers. The hAAT, mAIb, and rPEPCK promoters were, respectively, 35- , 8-, and 0.02-fold as strong as the previously studied constitutive Pol-II promoter. We conclude that the hAAT promoter resulted in the highest expression from a retroviral vector and may result in therapeutically significant expression of other clinically significant blood proteins.  相似文献   
17.
Lytton  SD; Mester  B; Libman  J; Shanzer  A; Cabantchik  ZI 《Blood》1994,84(3):910-915
Iron chelation treatment of red blood cells infected with Plasmodium falciparum selectively intervenes with iron-dependent metabolism of malaria parasites and inhibits their development. Highly permeant hydroxamate iron chelator RSFileum2 affects all parasite stages when cultures are continuously exposed to drug, but affects primarily ring stages when assessed for irreversible effects, ie, sustained inhibition remaining after drug removal. On the other hand, the hydrophilic and poorly permeant desferrioxamine (DFO) affects primarily trophozoite/schizont stages when tested either in the continuous mode or irreversible mode. Unlike parasites, mammalian cells subjected to similar drug treatment show complete growth recovery once drugs are removed. Our studies indicate that parasites display a limited capacity to recover from intracellular iron depletion evoked by iron chelators. Based on these findings we provide a working model in which the irreversible effects of RSFs on rings are explained by the absence of pathways for iron acquisition/utilization by early forms of parasites. Trophozoite/schizonts can partially recover from RSFileum2 treatments, but show no DNA synthesis following DFO treatment even after drug removal and iron replenishment by permeant iron carriers. At trophozoite stage, the parasite uses a limited pathway for refurnishing its iron-containing enzymes, thus overcoming iron deprivation caused by permeant RSFileum2, but not by DFO because this latter drug is not easily removable from parasites. Their DNA synthesis is blocked by the hydroxamate iron chelators probably by affecting synthesis of ribonucleotide reductase (RNRase). Presumably in parasites, prolonged repression of the enzyme leads also to irreversible loss of activity. The action profiles of RSFileum2 and DFO presented in this study have implications for improved chemotherapeutic performance by combined drug treatment and future drug design based on specific intervention at parasite DNA synthesis.  相似文献   
18.
19.
20.
OBJECTIVE: To compare self-administered versions of three questionnaires for detecting heavy and problem drinking: the CAGE, the Alcohol Use Disorders Identification Test (AUDIT), and an augmented version of the CAGE. DESIGN: Cross-sectional surveys. SETTING: Three Department of Veterans Affairs general medical clinics. PATIENTS: Random sample of consenting male outpatients who consumed at least 5 drinks over the past year (“drinkers”). Heavy drinkers were oversampled. MEASUREMENTS: An augmented version of the CAGE was included in a questionnaire mailed to all patients. The AUDIT was subsequently mailed to “drinkers.” Comparison standards, based on the tri-level World Health Organization alcohol consumption interview and the Diagnostic Interview Schedule, included heavy drinking (>14 drinks per week typically or ≥5 drinks per day at least monthly) and active DSM-IIIR alcohol abuse or dependence (positive diagnosis and at least one alcohol-related symptom in the past year). Areas under receiver operating characteristic curves (AUROCs) were used to compare screening questionnaires. MAIN RESULTS: Of 393 eligible patients, 261 (66%) returned the AUDIT and completed interviews. For detection of active alcohol abuse or dependence, the CAGE augmented with three more questions (AUROC 0.871) performed better than either the CAGE alone or AUDIT (AUROCs 0.820 and 0.777, respectively). For identification of heavy-drinking patients, however, the AUDIT performed best (AUROC 0.870). To identify both heavy drinking and active alcohol abuse or dependence, the augmented CAGE and AUDIT both performed well, but the AUDIT was superior (AUROC 0.861). CONCLUSIONS: For identification of patients with heavy drinking or active alcohol abuse or dependence, the self-administered AUDIT was superior to the CAGE in this population. This research was supported by Department of Veteran Affairs, Hines Center for Cooperative Studies in Health Services Research, grant 91-007, and Health Services Research and Development, grant SDR 96-002, Ambulatory Care Quality Improvement Project (ACQUIP); a grant from the University of Washington Alcohol and Drug Abuse Institute; and the Health Services Research and Development Field Program and Medical Service, Seattle Division, VA Pudget Sound Health Care System.  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