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   182篇
  免费   10篇
  国内免费   1篇
耳鼻咽喉   10篇
儿科学   2篇
基础医学   27篇
口腔科学   1篇
临床医学   18篇
内科学   59篇
皮肤病学   1篇
神经病学   4篇
特种医学   9篇
外科学   14篇
综合类   3篇
预防医学   24篇
药学   16篇
肿瘤学   5篇
  2021年   1篇
  2020年   1篇
  2019年   2篇
  2018年   5篇
  2017年   1篇
  2016年   1篇
  2015年   4篇
  2014年   5篇
  2013年   5篇
  2012年   11篇
  2011年   6篇
  2010年   3篇
  2009年   2篇
  2008年   11篇
  2007年   7篇
  2006年   13篇
  2005年   10篇
  2004年   8篇
  2003年   7篇
  2002年   2篇
  2001年   4篇
  2000年   7篇
  1999年   3篇
  1998年   1篇
  1997年   1篇
  1995年   3篇
  1994年   2篇
  1993年   1篇
  1992年   4篇
  1991年   11篇
  1990年   1篇
  1989年   5篇
  1988年   2篇
  1987年   1篇
  1986年   3篇
  1985年   4篇
  1983年   1篇
  1979年   2篇
  1978年   4篇
  1976年   3篇
  1975年   4篇
  1973年   4篇
  1972年   1篇
  1971年   4篇
  1970年   1篇
  1969年   3篇
  1968年   2篇
  1967年   2篇
  1966年   1篇
  1965年   2篇
排序方式: 共有193条查询结果,搜索用时 15 毫秒
1.
BACKGROUND: Apple allergy is dominated by IgE antibodies against Mal d 1 in areas where birch pollen is endemic. Apples with significantly decreased levels of Mal d 1 would allow most patients in these areas to eat apples without allergic reactions. OBJECTIVE: The aim of this study was to inhibit the expression of Mal d 1 in apple plants by RNA interference. METHODS: In vitro -grown apple plantlets were transformed with a construct coding for an intron-spliced hairpin RNA containing a Mal d 1-specific inverted repeat sequence separated by a Mal d 1-specific intron sequence. The presence of the construct in transformants was checked by PCR. Expression of Mal d 1 in leaves was monitored by prick-to-prick skin testing in 3 patients allergic to apples and by immunoblotting with a Mal d 1-reactive mAb and with IgE antibodies against Mal d 1. RESULTS: After transformation, plantlets were selected on the basis of having a normal phenotype and growth rate. With PCR, in 6 of 9 selected plantlets, the presence of the gene-silencing construct was demonstrated. By skin prick test it was shown that a wild-type plantlet had significantly ( P < .05) higher allergenicity than 5 of the transformants. Reduction of expression of Mal d 1 was confirmed by immunoblotting. In wild-type and unsuccessful transformants, a strong band was detected with Mal d 1-reactive mAb 5H8 at the expected apparent M r of 17 kDa. This band was virtually absent in the transformants that carried the gene-silencing construct. With human IgE antibodies, the same observations were made. CONCLUSIONS: Mal d 1 expression was successfully reduced by RNA interference. This translated into significantly reduced in vivo allergenicity. These observations support the feasibility of the production by gene silencing of apples hypoallergenic for Mal d 1.  相似文献   
2.
3.
4.
Patients with underlying cardiovascular conditions are particularly vulnerable to severe COVID-19. In this project, we aimed to characterize similarities in dysregulated immune pathways between COVID-19 patients and patients with cardiomyopathy, venous thromboembolism (VTE), or coronary artery disease (CAD). We hypothesized that these similarly dysregulated pathways may be critical to how cardiovascular diseases (CVDs) exacerbate COVID-19. To evaluate immune dysregulation in different diseases, we used four separate datasets, including RNA-sequencing data from human left ventricular cardiac muscle samples of patients with dilated or ischemic cardiomyopathy and healthy controls; RNA-sequencing data of whole blood samples from patients with single or recurrent event VTE and healthy controls; RNA-sequencing data of human peripheral blood mononuclear cells (PBMCs) from patients with and without obstructive CAD; and RNA-sequencing data of platelets from COVID-19 subjects and healthy controls. We found similar immune dysregulation profiles between patients with CVDs and COVID-19 patients. Interestingly, cardiomyopathy patients display the most similar immune landscape to COVID-19 patients. Additionally, COVID-19 patients experience greater upregulation of cytokine- and inflammasome-related genes than patients with CVDs. In all, patients with CVDs have a significant overlap of cytokine- and inflammasome-related gene expression profiles with that of COVID-19 patients, possibly explaining their greater vulnerability to severe COVID-19.  相似文献   
5.
Pulmonary embolism in respiratory failure   总被引:1,自引:0,他引:1  
A Neuhaus  R R Bentz  J G Weg 《Chest》1978,73(4):460-465
The occurrence of pulmonary emboli in 617 patients admitted to a respiratory intensive care unit was studied. Pulmonary emboli were found in 18 (27 percent) of 66 autopsies. Half of these pulmonary emboli were not diagnosed before death, despite persistent aggressive attempts to document pulmonary emboli. In this subpopulation of patients with respiratory failure, the usual clinical manifestations of pulmonary emboli (symptoms, signs, chest x-ray film, electrocardiogram, and changes in arterial blood gas levels) frequently are already present, due to the severe underlying pulmonary disease, and any superimposed manifestations of pulmonary emboli are often inapparent. In this group under study, the ventilation/perfusion lung scan correlated poorly with pulmonary angiographic results and with examinations at autopsy; the scan generally was inadequate to rule in or rule out pulmonary emboli. Again, this was due to the distortion of both ventilation and perfusion by the severe underlying pulmonary disease. Currently, pulmonary angiographic studies remain the only reliable technique to confirm or exclude pulmonary emboli in patients with respiratory failure.  相似文献   
6.
OBJECTIVE: To examine differences in resting energy expenditure (REE) between black and white smokers in order to determine whether REE might contribute to postcessation weight gain. DESIGN: Cross-sectional and prospective investigation of ethnic differences in REE. Differences in REE between black and white smokers were examined at baseline while all participants were smoking, and again during 2 weeks of abstinence from smoking. SETTING: Memphis, Tennessee, USA. SUBJECTS: Sixty-six black and 112 white smokers (age 30.4 y; cigarettes per day 21.4; weight 71.7 kg; body mass index 24.5 kg/m2). RESULTS: Black smokers had a significantly lower baseline REE after adjusting for gender and body weight. Changes in REE following smoking cessation did not differ by ethnicity. CONCLUSIONS: These results suggest that black smokers may be more energy efficient, which could contribute to ethnic differences in postcessation weight gain.  相似文献   
7.
Comparison of weight status among two cohorts of US Air Force recruits   总被引:2,自引:0,他引:2  
BACKGROUND: Overweight and obesity are increasing rapidly in the US and the Department of Defense (DoD). We examined whether weight trends evidenced in the general population and DoD are occurring among individuals entering US Air Force (USAF) Basic Military Training (BMT). METHODS: Individuals entering the USAF in 1996 (AF1996; N = 29,036) and 2000 (AF2000; N = 31,080), ages 17-29 years were surveyed. The two recruit cohorts were compared to age-matched individuals from the 1996 (N = 22,153) and 2000 (N = 31,861) Behavioral Risk Factor Surveillance System Survey (BRFSS). RESULTS: Crude rates for all age groups and age- and gender-standardized prevalence rates reflected significant increases in overweight/obesity among recruits. The direct standardized prevalence of overweight/obesity increased nearly 24%, from 14.8% in AF1996 to 18.3% in AF2000. The increase in overweight/obesity was particularly large among male recruits ages 25-29 (i.e., from 36.4% to 44.5%) between 1996 and 2000. CONCLUSIONS: USAF cohorts were less likely to be overweight than corresponding BRFSS samples. There were 19.1 and 20.2 percentage point differences between overall crude rates of overweight/obesity between AF1996 and BRFSS 1996 and AF2000 and BRFSS 2000, respectively. Nevertheless, overall rates of overweight and obesity are increasing among young recruits in the USAF at a fairly marked rate (approximately one percentage point per year).  相似文献   
8.
BACKGROUND AND PURPOSE: Surgical treatment of traumatic spinal injury should include fast and complete decompression of spinal cord and radices wits reduction of broken vertebral body, restoration of physiological spinal curvatures and spondylodesis of injured segments. Restoration of natural spinal curvatures is only possible when the height of broken vertebral body is reconstructed. MATERIAL AND METHODS: Between 1992 and 2001, 75 patients were operated on because of traumatic injuries of thoracolumbar spine in the Ortopaedic and Traumatology Department Skubiszewski Medical University of Lublin. 48 patients had broken vertebral body reduction with simultaneous filling of bone loss with autogenic bone grafts inserted through pediculum. Only in 4 cases posterior spondylodesis was carried out on arches and spinous processes. Transpedicular plasty of 44 broken vertebral bodies was connected with posterior interbody fusion with PLIF technique using graft application to interbody space. RESULTS: The operative protocol presented above allowed for the height of the anterior vertebral wall to be restored on average to 81.5% of the original height. We did not observe either fatigue breakage of the screws or screws loosening with kyphosis recurrence. We did not note serious postoperative complications, including neurological compromise. The operative procedure did not significantly change the neurological status of the patients. In 9 cases we noted neurological improvement: usually by 1 or 2 grades in Frankel's score. CONCLUSIONS: Restoration of the fractured vertebral body with bone grafts combined with posterior interbody spondylodesis effectively prevents the recurrence of the kyphotic deformation.  相似文献   
9.
BACKGROUND: Smoking prevalence rates remain high among women and smoking initiation has increased for young adults. Little is known about the unique patterns of smoking, risk factors, and correlates of quitting in Black versus White women of child-bearing age. METHOD: This study examined the relationships among smoking, ethnicity, socioeconomic status (SES), and lifestyle variables among 715 women (43.6% Blacks and 56.4% Whites). Stringent inclusion criteria were used for ethnicity, which allows for distinct comparisons but may reduce generalizability of results. RESULTS: Black current smokers smoked fewer cigarettes per day and reported initiating smoking at a later age than Whites. Current versus never smoking was associated with income, education, and caffeine intake. There was a significant ethnicity by alcohol interaction (at lower levels of alcohol intake Whites were more likely to smoke but at higher levels of alcohol there were no ethnic differences). Former smoking versus current smoking was associated with alcohol intake, education, and pack years of smoking. CONCLUSIONS: The results of the study suggest several ethnic differences in smoking patterns as well as several correlates of smoking status. These results have implications for the tailoring of interventions and illustrate the association of other health risk factors with smoking status.  相似文献   
10.
Over the last four decades there have been remarkable advances in the diagnosis and treatment of venous thromboembolism (VTE)-pulmonary embolism (PE) and deep venous thrombosis (DVT). We have moved from no objective documentation to a plethora of ever improving imaging studies. Evolving treatment modalities have reduced the mortality due to PE to approximately 2%. Shorter hospitalizations followed by outpatient therapy are a growing reality. The use of primary prophylaxis is increasing, but more widespread use must be encouraged. Despite the many accomplishments, too many patients with VTE with its high mortality without treatment remain undiagnosed. There is a critical need to improve the role of the patient's history in identifying patients who warrant objective testing. The ideal would be the development of a biological marker of VTE, similar to the creatinine kinase-MB, creatinine kinase-MM, or troponin I in acute myocardial infarction.  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