全文获取类型
收费全文 | 110篇 |
免费 | 11篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 38篇 |
机械仪表 | 4篇 |
建筑科学 | 3篇 |
能源动力 | 1篇 |
轻工业 | 37篇 |
水利工程 | 1篇 |
无线电 | 7篇 |
一般工业技术 | 4篇 |
冶金工业 | 5篇 |
原子能技术 | 2篇 |
自动化技术 | 18篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 1篇 |
2014年 | 6篇 |
2013年 | 9篇 |
2012年 | 7篇 |
2011年 | 4篇 |
2010年 | 8篇 |
2009年 | 6篇 |
2008年 | 10篇 |
2007年 | 3篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1993年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1963年 | 2篇 |
1962年 | 2篇 |
排序方式: 共有121条查询结果,搜索用时 31 毫秒
1.
Children, teenagers, and adults abundantly use the Web to search for information. Yet this high frequency of use stands in marked contrast with the users’ relatively low awareness and mastery of metacognitive skills to search the Web effectively and efficiently. This paper provides a review of five different studies that sought to overcome these skill deficiencies by various kinds of instructional and environmental support. Following a discussion on the use of cognitive models of the search process in designing Web searching instruction and support, the studies’ findings are considered in view of their aim and approach in supporting metacognition. 相似文献
2.
Ard RW 《Environmental science & technology》1976,10(3):239-242
3.
Thorsteinn Astradsson Felix Sellberg Ylva Tiblom Ehrsson Karl Sandstrm Gran Laurell 《International journal of molecular sciences》2022,23(11)
In this real-world study, the aims were to prospectively evaluate the expression of inflammatory proteins in serum collected from head and neck cancer patients before and after treatment, and to assess whether there were differences in expression associated with treatment modalities. The mixed study cohort consisted of 180 patients with head and neck cancer. The most common tumor sites were the oropharynx (n = 81), the oral cavity (n = 53), and the larynx (n = 22). Blood tests for proteomics analysis were carried out before treatment, 7 weeks after the start of treatment, and 3 and 12 months after the termination of treatment. Sera were analyzed for 83 proteins using an immuno-oncology biomarker panel (Olink, Uppsala, Sweden). Patients were divided into four treatment groups: surgery alone (Surg group, n = 24), radiotherapy with or without surgery (RT group, n = 94), radiotherapy with concomitant cisplatin (CRT group, n = 47), and radiotherapy with concomitant targeted therapy (RT Cetux group, n = 15). For the overall cohort, the expression levels of 15 of the 83 proteins changed significantly between the pretreatment sample and the sample taken 7 weeks after the start of treatment. At 7 weeks after the start of treatment, 13 proteins showed lower expression in the CRT group compared to the RT group. The majority of the inflammatory proteins had returned to their pretreatment levels after 12 months. It was clearly demonstrated that cisplatin-based chemoradiation has immunological effects in patients with head and neck cancer. This analysis draws attention to several inflammatory proteins that are of interest for further studies. 相似文献
4.
Dr. Pablo Valverde J. Daniel Martínez Prof. F. Javier Cañada Dr. Ana Ardá Prof. Jesús Jiménez-Barbero 《Chembiochem : a European journal of chemical biology》2020,21(21):2999-3025
Carbohydrates play a pivotal role in intercellular communication processes. In particular, glycan antigens are key for sustaining homeostasis, helping leukocytes to distinguish damaged tissues and invading pathogens from healthy tissues. From a structural perspective, this cross-talk is fairly complex, and multiple membrane proteins guide these recognition processes, including lectins and Toll-like receptors. Since the beginning of this century, lectins have become potential targets for therapeutics for controlling and/or avoiding the progression of pathologies derived from an incorrect immune outcome, including infectious processes, cancer, or autoimmune diseases. Therefore, a detailed knowledge of these receptors is mandatory for the development of specific treatments. In this review, we summarize the current knowledge about four key C-type lectins whose importance has been steadily growing in recent years, focusing in particular on how glycan recognition takes place at the molecular level, but also looking at recent progresses in the quest for therapeutics. 相似文献
5.
The minimalist approach (Carroll, 1990a) advocates the development of a radically different type of manual when compared to a conventional one. For example, the manual should proceed almost directly to procedural skills development rather than building a conceptual model first. It ought to focus on authentic tasks practised in context, as opposed to mock exercises and isolated practice. In addition, it should stimulate users to exploit their knowledge and thinking, as opposed to imposing the writer's view and discussing everything that users should see or know.
In the first part of the paper the construction of a tutorial based on the minimalist principles is described. A parallel is drawn with constructivism with which minimalism shares important notions of instruction. In the second part, an experiment is described in which the minimal manual was tested against a conventional one. The outcome favoured the new manual. For example, minimal manual users completed about 50% more tasks successfully on a performance test and displayed significantly more self-reliance (e.g. more self-initiated error-recoveries, and fewer manual consultations). 相似文献
6.
The chemical composition of the water-soluble extracts of mature Cheddar cheese were identified, with the emphasis on understanding the interplay of compounds contributing to the savoury taste in Cheddar. The ultra-filtered water-soluble extracts of two mature Cheddar cheeses were fractionated by gel permeation chromatography (GPC). By sensory evaluation, two taste-active GPC fractions were identified from each cheese. On the basis of chemical profiling of these fractions, aqueous model tastant mixtures were prepared and sensory omission tests carried out. Glutamic acid, organic acids and mineral salts were the main tastants, whereas the other amino acids had a limited impact on taste. The characteristic umami taste was explained by a synergistic effect of glutamic acid and salts. Matching umami taste intensities were obtained from different concentrations of glutamic acid and salts. Unmasking of a bitter or sweet taste from mixtures of sub-threshold concentrations of amino acids without glutamic acids was also observed. 相似文献
7.
8.
Montserrat Pinent Anna Castell Isabel Baiges Gemma Montagut Lluís Arola Anna Ardévol 《Comprehensive Reviews in Food Science and Food Safety》2008,7(4):299-308
ABSTRACT: Flavonoids are usually found in fruits and other plant organs and therefore widely consumed. They are antioxidants, anti‐inflammatory, anticarcinogenic, and protective against coronary disease and metabolic disorders. These beneficial effects make them good candidates for the development of new functional foods with potential protective/preventive properties against several diseases. We must consider that this fact could lead to a higher intake of some of these flavonoids. Most of the studies concerning their beneficial effects showed peripheral activity of these molecules, but there is no clear information about their central effects on a key organ on metabolic control: the endocrine pancreas. The pancreas has an endocrine function of major importance to regulate nutrient metabolism, such as control of glucose homeostasis via insulin and glucagon secretion. Its importance in whole body nutrient equilibrium is highlighted by the fact that several pathologies, such as type 1 and/or 2 diabetes, are related at some point to a pancreatic cell deregulation. In this review, we compile the most relevant results concerning the effects of flavonoids on several aspects of pancreatic functionality. Studies using animals with drug‐induced diabetes support the hypothesis that flavonoids can ameliorate this pathogenesis. The great diversity of flavonoid structures makes it difficult to establish common effects in the pancreas. Published data suggest that there might be direct effects of flavonoids on insulin secretion, as well as on prevention of beta‐cell apoptosis, and they could even act via modulation of proliferation. The mechanisms of action involve mainly their antioxidant properties, but other pathways might also take place. 相似文献
9.
Ylva Hillbur Ashraf El-Sayed Marie Bengtsson Jan Löfqvist Anthony Biddle Ernst Plass Wittko Francke 《Journal of chemical ecology》2000,26(8):1941-1952
Behavioral activity of the recently identified sex pheromone components of the pea midge, Contarinia pisi, (2S,11S)-diacetoxytridecane, (2S,12S)-diacetoxytridecane, and 2-acetoxytridecane, was tested in wind tunnel and field-trapping experiments. In the wind tunnel, the attractancy of the three-component blend in a 7 : 10 : 0.1 ratio (following the above order, mimicking the ratios found in gland extract) did not differ significantly from female gland extract, whereas a mixture of the two major components (7 : 10) only attracted 2% of the males to the source. In the field, traps baited with the three-component blend caught by far the largest number of males. Traps baited with the two major components only caught slightly more than the blank traps, and catches in traps baited with 2-acetoxytridecane alone did not differ from catches in the blank traps. Traps baited with the racemate of all three components did not catch more than the blank traps, indicating that some of the enantiomers are inhibitory. 相似文献
10.
Milk subjected to instant infusion pasteurization (IIP) at 72 °C, 100 °C and 120 °C (holding time 0.2 s) exhibited increased rennet coagulation time and decreased curd firming rate for increasing heat treatment temperature, when compared with raw or high temperature short time pasteurized (HTST) milk. However, addition of 4.5 mm or 9.0 mm of calcium restored the impaired rennet coagulation ability. Open texture cheeses produced from IIP milk (100 °C and 120 °C) contained significantly more moisture, had lower pH and shorter texture than similar cheese from IIP at 72 °C and HTST pasteurized milk. Cheese ripening was also affected by heat treatment, and different patterns of casein breakdown and peptide formation resulted from cheeses made from milk treated to IIP at 100 °C and 120 °C compared with cheeses made using IIP at 72 °C or HTST. 相似文献