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   321篇
  免费   17篇
电工技术   3篇
化学工业   65篇
金属工艺   6篇
机械仪表   2篇
建筑科学   18篇
矿业工程   1篇
能源动力   15篇
轻工业   101篇
水利工程   2篇
石油天然气   1篇
无线电   9篇
一般工业技术   38篇
冶金工业   59篇
原子能技术   2篇
自动化技术   16篇
  2023年   2篇
  2022年   5篇
  2021年   10篇
  2020年   3篇
  2019年   11篇
  2018年   4篇
  2017年   7篇
  2016年   9篇
  2015年   8篇
  2014年   9篇
  2013年   18篇
  2012年   22篇
  2011年   25篇
  2010年   10篇
  2009年   14篇
  2008年   21篇
  2007年   16篇
  2006年   7篇
  2005年   7篇
  2004年   6篇
  2003年   18篇
  2002年   8篇
  2001年   4篇
  2000年   4篇
  1999年   7篇
  1998年   13篇
  1997年   9篇
  1996年   6篇
  1995年   6篇
  1994年   4篇
  1993年   2篇
  1992年   3篇
  1990年   5篇
  1986年   3篇
  1985年   2篇
  1984年   4篇
  1982年   4篇
  1978年   1篇
  1976年   1篇
  1974年   1篇
  1968年   1篇
  1966年   1篇
  1965年   1篇
  1961年   1篇
  1960年   2篇
  1959年   2篇
  1957年   1篇
  1956年   2篇
  1955年   3篇
  1954年   1篇
排序方式: 共有338条查询结果,搜索用时 31 毫秒
11.
The natural antimicrobial compound allyl isothiocyanate (AITC), found in mustard oil, is effective against cheese-related fungi both on laboratory media and cheese. Penicillium commune, Penicillium roqueforti, and Aspergillus flavus were more sensitive to AITC when it was added just after the spores had completed 100% germination and branching had started on Czapek yeast extract agar than were spores in the dormant phase. The use of 1 AITC label (Wasaouro interior labels, LD30D, 20 by 20 mm) in combination with atmospheric air in the packaging extended the shelf life of Danish Danbo cheese from 4 1/2 to 13 weeks. Two AITC labels extended the shelf life from 4 1/2 to 28 weeks. Both 1 and 2 labels in combination with modified atmosphere packaging extended the shelf life of the cheese from 18 to 28 weeks. This study showed that AITC was absorbed in the cheese, but it was not possible to detect any volatile breakdown products from AITC in the cheese. Cheese stored for up to 12 weeks with an AITC label had an unacceptable mustard flavor. The mustard flavor decreased to an acceptable level between weeks 12 and 28. Cheese stored in atmospheric air had a fresher taste without a CO2 off-flavor than did cheese stored in modified atmosphere packaging. AITC may be a good alternative to modified atmosphere packaging for cheese. The extended shelf life of cheese in the package is very desirable: the cheese can be transported longer distances, and the packaging can be used for the final maturing of the cheese. Furthermore, AITC can address problems such as pinholes and leaking seals in cheese packaging.  相似文献   
12.
Mycoplasma bovis is an important pathogen causing disease and substantial economic losses in cattle. However, knowledge of the dynamics of antibody responses in individual cows in the face of an outbreak is currently extremely limited. The use of commercial antibody tests to support clinical decision-making and for surveillance purposes is therefore challenging. Our objective was to describe the dynamics of M. bovis antibody responses in 4 Danish dairy herds experiencing an acute outbreak of M. bovis-associated disease, and to compare the antibody dynamics between dairy cows with different disease manifestations. A total of 120 cows were examined using a standardized clinical protocol and categorized into 4 disease groups: “mastitis,” “systemic,” “nonspecific,” and “none.” Paired blood and milk samples were collected and tested using a commercial M. bovis antibody–detecting ELISA. Plots of raw data and generalized additive mixed models with cow and herd as random effects were used to describe serum and milk antibody dynamics relative to the estimated time of onset of clinical disease. Cows with mastitis had high optical density measurement (ODC%) of antibodies in both milk and serum at disease onset. The estimated mean ODC% in milk was below the manufacturer's cut-off for the other groups for the entire study period. The estimated mean serum ODC% in the “systemic” group was high at onset of disease and stayed above the cut-off until 65 d after disease onset. However, the lower 95% confidence interval (CI) for the mean ODC% was only above the manufacturer's cut-off between 7 and 17 d after onset of disease. The CI of the “systemic” and “none” groups did not overlap at any time between the day of disease onset and 65 d after disease onset, and the estimated mean ODC% for both the “nonspecific” and “none” groups were generally below the cut-off for the majority of the study period. In conclusion, the serum antibody responses were highly dynamic and showed a high level of variation between individual cows. This strongly suggests that serology is unlikely to be useful for individual diagnosis of M. bovis-associated disease in dairy cows. However, it might still be useful for herd- or group-level diagnosis. Antibodies in milk were only increased in cows with M. bovis mastitis, indicating that milk antibody measurements only have diagnostic utility for cows with mastitis.  相似文献   
13.
14.
The power systems in Denmark, Spain, Ireland, and New Zealand have some of the highest wind penetrations in the world (see Table 1). The management of the different power systems to date, with increasing amounts of wind energy, has been successful. There have been no incidents in which the wind has directly or indirectly been a major factor causing operational problems for the system. However, there are a number of parameters that are being monitored that indicate the need for active management in the near future (and in some cases already today). In this article, we briefly describe the situations in these four countries, giving special emphasis to the market integration of wind power, the use of wind forecasting, and curtailment experience. The final section provides an overview of the main wind forecasting methodologies and challenges.  相似文献   
15.
16.
A novel approach was applied in this study to directly evaluate the effect of muscle fiber type on postmortem protein degradation. Porcine muscle fibers were isolated from longissimus muscle at day 1, 3, and 6 postmortem. Fibers were sorted by immunochemical myosin heavy chain isoform typing. Western blot analysis of fibers pooled separately into type I or IIb showed that the relative amounts of 39- and 50-kDa desmin degradation fragments at day 6, and 28- to 31-kDa fragments of troponin T fast type isoform (fTnT) at day 1 and 6 postmortem were higher in type IIb than in type I fibers. At day 6 troponin T slow type isoform (sTnT) was less degraded than fTnT in type I fibers. These results indicated greater rate and extent of proteolysis in type IIb than in type I fibers and higher susceptibility of fTnT to proteolysis than that of sTnT isoform.  相似文献   
17.
Nachdruck:     
Alexander Mette 《NTM》2010,18(3):337-355
  相似文献   
18.
Towards the first generation micro bulk forming system   总被引:3,自引:0,他引:3  
The industrial demand for micro mechanical components has surged in the later years with the constant introduction of more integrated products. The micro bulk forming process holds a promising pledge of delivering high quality micro mechanical components at low cost and high production rates. This work describes a number of prototype system units, which collectively form a desktop sized micro forming production system. The system includes a billet preparation module, an integrated transfer system, a temperature controlled forming tool, including process simulation, and a dedicated micro forming press. The system is demonstrated on an advanced micro forming case where a dental component is formed in medical grade Titanium.  相似文献   
19.
20.
The aim of this study was to provide valid data on the demography, medical history and clinical findings among adult women presenting with urinary incontinence to general practitioners. In a rural community in Norway, all women > 20 years who consulted their general practitioner for urinary incontinence during a 3 year period were included in a prospective study. A thorough medical history and both a general and focused clinical examination were undertaken. Gynecological examination, stress provocation test, and 48 h frequency/volume chart and pad weighing test were also performed. 105 women were included (4.4% of women > 20 years in the total population). Mean age was 57 years, 64% were postmenopausal. A lot of comorbidity was reported. Duration of incontinence was > 5 years in 49%. By a severity index, 64% were classified as severe, 28% as moderate and 8% as having slight incontinence. 59% were using protective pads or garments. Mean leakage per 24 h was 31 g. 38% had significant genital prolapse. Contractility of the pelvic floor muscles was weak in 28%. Diagnostic classification revealed 50% stress incontinence, 10% urge and 40% mixed incontinence. 42% of the patients were a great deal or much bothered by their incontinence. Patients with stress incontinence were less bothered than others. Women presenting with urinary incontinence at a primary care level are prevalent, and often have significant incontinence. It is a challenge for the general practitioners to investigate and treat these patients optimally.  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