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   74篇
  免费   4篇
电工技术   2篇
化学工业   13篇
建筑科学   1篇
能源动力   1篇
轻工业   5篇
无线电   18篇
一般工业技术   4篇
冶金工业   31篇
自动化技术   3篇
  2021年   1篇
  2020年   3篇
  2018年   4篇
  2017年   1篇
  2016年   1篇
  2013年   1篇
  2012年   2篇
  2011年   4篇
  2010年   2篇
  2009年   7篇
  2008年   3篇
  2006年   3篇
  2005年   3篇
  2004年   2篇
  2003年   1篇
  2002年   3篇
  1999年   1篇
  1998年   12篇
  1997年   9篇
  1996年   6篇
  1995年   4篇
  1992年   1篇
  1984年   1篇
  1982年   2篇
  1977年   1篇
排序方式: 共有78条查询结果,搜索用时 15 毫秒
1.
Proliferation and apoptosis of neoplastic cells are prognostic biomarkers in plasma cell neoplasms (PCNs). The prognostic capacity of proliferation to apoptosis ratio (Ratio-PA) in the era of immunomodulatory treatments is re-evaluated in 316 gammopathy of undetermined significance (MGUS), 57 smoldering multiple myeloma (SMM), and 266 multiple myeloma (MM) patients. Ratio-PA of 0.77 ± 0.12, 1.94 ± 0.52, and 11.2 ± 0.7 (p < 0.0001) were observed in MGUS, SMM, and MM patients. Ten-year overall survival (10y-OS) rates for patients with low/high Ratio-PA were 93.5%/77.3% p < 0.0001) for MGUS, 82.5%/64.7% (p < 0.05) for SMM, and 62.3%/47.0% (p < 0.05) for MM. For patients with low, intermediate, and high risk, 10y-OS for low/high Ratio-PA were 95.5%/72.9% (p < 0.0001), 74.2%/50.4% (p < 0.0001), and 35.3%/20.0% (p = 0.836), respectively. Ratio-PA was an independent prognostic factor for OS (HR = 2.119, p < 0.0001, Harrell-C-statistic = 0.7440 ± 0.0194) when co-analyzed with sex, age, and standard risk. In patients with Ratio-PAhigh, only first-line therapy with VRd/VTd, but not PAD/VCD, coupled with ASCT was associated with high 10y-OS (82.7%). Tumor cell Ratio-PA estimated at diagnosis offers a prognostic biomarker that complements standard risk stratification and helps to guide the clinical management of pre-malignant and symptomatic PCNs. Every effort should be made to provide first-line therapies including VTd or VRd associated with ASCT to patients with Ratio-PAhigh at higher risk of progression and death.  相似文献   
2.
Melanoma is the most deathful of all skin cancers and the number of cases grows every year. The extirpation in early phases implies a high degree of survival so it is fundamental to diagnose it as soon as possible. In this paper we present a clinical decision support system for melanoma diagnosis using as input an image set of the skin lesion to be diagnosed. The system analyses the image sequence to extract the affected area, determinates the characteristics which indicate the degree of damage and, according to them, it makes a decision. Several methods of classification are proposed: a multilayered perceptron, a Bayesian classifier and the algorithm of the K nearest neighbours. These methods work independently and also in combination making a collaborative decision support system. The classification rates obtained are around 87%.  相似文献   
3.
Photoreflectance (PR) measurements were performed on specific structures grown by molecular-beam epitaxy on different substrate orientations: 111B, 111B 2° off, 111A and 100. A strained In0.2Ga0.8As quantum well was grown in the space charge layer of an undoped GaAs layer. On a polar substrate orientation 111, the strain-induced piezoelectric field in the quantum well modifies the field in the space charge layer. PR spectra recorded in such structures exhibit Franz Keldysh oscillations from which we can measure the internal electric field. The piezoelectric field is then deduced from a comparison between two structures differing only by the presence of the strained quantum well. Experimental values ranged between 110 kV/cm and 150 kV/cm, and were used to determine experimentally the piezoelectric constant e14 in In0.2Ga0.8As.  相似文献   
4.
R. Berenguer  C. Quijada  E. Morallón 《Carbon》2010,48(10):2734-2745
The electrochemical regeneration of phenol-saturated activated carbon has been carried out in a filter-press electrochemical cell. The feasibility of the electrochemical regeneration has been assessed by monitoring the regeneration efficiency and the textural properties of a phenol-saturated granular activated carbon (GAC) electrolysed in NaOH medium. The influence of the following factors: (i) the electrolysis treatment (either anodic or cathodic); (ii) the separation of compartments; (iii) applied current and (iv) electrolysis time has been studied. Basing on the obtained results, an overall phenomenological mechanism for the electrochemical regeneration has been proposed. The general worse performance of anodic regenerations can be attributed to an important surface blockage of the GAC by reaction products such as quinones, phenolic oligomers and polymers coming from phenol electrooxidation. The cathodic regeneration in NaOH medium, where phenolate desorption is favoured, and in an undivided configuration, where surface blockage is minimized, produces a significant recovery of the porosity of the original GAC, in agreement with the highest RE values (close to 80%).  相似文献   
5.
In the framework of context awareness within the home, our team is currently assessing the unobtrusive detection of inhabitants' activity through the monitoring of their use and consumption of electricity. The objective is to develop a system for the remote monitoring of large populations of elderly people living independently at home. To be readily deployable on the field, such a system must be minimally intrusive both for the home environment and for the field professionals (paramedics and social workers) visiting the patients at home. We carried out two successive field experiments to evaluate and to improve our system designed to deliver a single index of daily activity. The first experiment involved 13 elderly persons over a nine-month period (84,240 h data recorded) and the second one 12 elderly over six months (51,840 h). We evaluated both the relevance of the index and the acceptability of the system as a whole. We discovered that electrical activity is a kind of unique "signature" of each person's activity. Moreover, this profile provides unexpected information on the health status of the subject. We confirmed that the system was unobtrusive and well accepted both by the subjects and by the professionals involved. Our unique index of activity, and its trend over time, can provide timely information to the professionals on the patient.  相似文献   
6.
The effects of smoking on the onset and clinical course of inflammatory bowel disease (IBD) have been widely debated. Although smoking appears to have a clearly unfavorable effect on the course in Crohn's Disease (CD), the relationship between smoking and localization of the disease is less clear. AIM: To evaluate, in our group of patients, the relationship between smoking and the development of ulcerative colitis (UC) or CD, and between smoking and the localization of CD in the large bowel or in other sites. PATIENTS AND METHODS: The smoking habits of 171 patients at the time of diagnosis were assessed with a questionnaire. Subjects were classified into three subgroups as smokers, nonsmokers and ex-smokers. Current smokers were grouped according to their level of consumption as those who smoked fewer than or more than 10 cigarettes per day. A total of 161 patients were studied (UC n = 69, CD n = 92). Patients with CD were divided into those with colonic disease and those with no colonic involvement. We evaluated the relationship between smoking and the form of IBD, localization (colonic or noncolonic) and the presence of perianal disease (PAD) in CD. The results were analyzed with the chi-squared test. RESULTS: Smoking was more frequent in patients with CD than in those with UC (72.8% vs 31.9%). Among patients with CD, more patients without colonic involvement were smokers (84.6% vs 64.2%). However, among patients with CD involving the colon, smoking was significantly more common (64.2%) than among patients who had UC (31.9%). CONCLUSIONS: Our findings confirm a relationship between smoking and CD. Smoking seems to be associated with some degree of protection of the colonic mucosa, especially in heavy smokers.  相似文献   
7.
We propose a state-based PM policy based on a stopping rule for an imperfectly monitored two-unit parallel system consisting of s-dependent units. The observed failure rate of the system is proposed as an efficient tool to integrate the imperfect monitoring information in the maintenance decision process : the possible nondetection of the failure of a unit and the monitoring quality are explicitly taken into account when optimizing the maintenance decisions. Using classical martingale results, a stochastic cost model is developed to assess the performance of the monitoring-maintenance policy for this system. Numerical experiments show that the PM policy based on the observed failure rate of the system is more robust to defective monitoring information and that it performs better than a policy which discards completely this imperfect information.  相似文献   
8.
The aim of this study was to know the prevalence of cholelithiasis (C) in the El Real-Gandia (Spain) as well as the degree of the response of the population. Health examinations were performed in 1,803 adults from El Real (2,000 inhabitants) and Gandia (54,000 inhabitants) using abdominal echography as the screening technique. Cholelithiasis was defined as the presence of biliary lithiasis (BL) or previous cholecystectomy (PC). Of 1,268 (70.3%) participants in the study, C was found in 126 cases (BL in 102 and P in 24) representing a standardized prevalence of around 15% in women and 5% in men. Cholelithiasis was more frequent in females (13.8%) than in males (5.7%) (p < 0.001) increasing linearly with age (p < 0.005). The proportion of PC was significantly higher in women (23.9%) than in men (5.9%) (p < 0.05) and in Gandia (34.4%) than in El Real (13.8%) (p < 0.02). The prevalence of biliary mud and polyps was of 0.3% and 1.1%, respectively. Working obligations (35.4%) and fear of hospitals (22.4%) were the most frequent causes for no response (NR). Males with more than primary a school education originating from outside the Valencian community (VC) were significantly associated with NR in multivariant analysis.  相似文献   
9.
The aim of this study was to assess the relationship between bulky DNA adducts in white blood cells (WBC) and lifestyle factors in a sample from the Spanish cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC). 296 subjects aged between 35 and 64 years, from five regions, were included. Food intake was estimated with a computerized version of dietary history questionnaire. Daily intake of polycyclic aromatic hydrocarbons (PAH) was estimated using a database with information on food content of potential carcinogens. Data on lifestyle and health factors were collected and DNA adducts measured using the nuclease P1 32P-postlabelling technique. Geometric means of adducts were similar for men and women (4.11/109 and 3.94/109 nucleotides, respectively). Highest levels of adduct were observed in non-smokers and non-occupationally exposed. Meat intake, oils and fats were associated with higher levels of adducts, but all non-statistically significant. Higher intakes of calcium, sodium and phosphorus were associated with lower adducts levels. Summarising, our study shows that bulky adducts measured by 32P-postlabelling in DNA from WBC do not correlate with the usual diet of healthy Spanish adults. Although it has been proposed that diet be the main source of PAH in nonsmokers without occupational exposure, DNA adducts do not seem to be suitable biomarkers of dietary PAH in general population.  相似文献   
10.
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