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   1561篇
  免费   50篇
  国内免费   1篇
电工技术   13篇
综合类   1篇
化学工业   327篇
金属工艺   21篇
机械仪表   18篇
建筑科学   89篇
矿业工程   3篇
能源动力   29篇
轻工业   197篇
水利工程   9篇
石油天然气   1篇
无线电   134篇
一般工业技术   240篇
冶金工业   364篇
原子能技术   18篇
自动化技术   148篇
  2023年   24篇
  2022年   33篇
  2021年   54篇
  2020年   26篇
  2019年   34篇
  2018年   34篇
  2017年   27篇
  2016年   33篇
  2015年   43篇
  2014年   51篇
  2013年   71篇
  2012年   73篇
  2011年   90篇
  2010年   70篇
  2009年   48篇
  2008年   82篇
  2007年   65篇
  2006年   63篇
  2005年   39篇
  2004年   24篇
  2003年   33篇
  2002年   36篇
  2001年   19篇
  2000年   21篇
  1999年   28篇
  1998年   88篇
  1997年   58篇
  1996年   50篇
  1995年   25篇
  1994年   24篇
  1993年   21篇
  1992年   15篇
  1991年   17篇
  1990年   11篇
  1989年   17篇
  1988年   11篇
  1987年   7篇
  1986年   10篇
  1985年   5篇
  1984年   8篇
  1983年   7篇
  1982年   10篇
  1980年   8篇
  1978年   10篇
  1977年   6篇
  1976年   13篇
  1974年   9篇
  1972年   7篇
  1969年   4篇
  1909年   4篇
排序方式: 共有1612条查询结果,搜索用时 15 毫秒
991.
Point-of-care (POC) diagnostic tests for the rapid detection of individuals infected with Mycobacterium leprae, the causative pathogen of leprosy, represent efficient tools to guide therapeutic and prophylactic treatment strategies in leprosy control programs, thus positively contributing to clinical outcome and reducing transmission of this infectious disease. Levels of antibodies directed against the M. leprae-specific phenolic glycolipid I (PGL−I) closely correlate with an individual's bacterial load and a higher risk of developing leprosy. We describe herein the assembly of a set of PGL glycans carrying the characteristic phenol aglycon and featuring different methylation patterns. The PGL trisaccharides were applied to construct neoglycoproteins that were used to detect anti-PGL IgM antibodies in leprosy patients. ELISAs and quantitative lateral-flow assays based on up-converting nanoparticles (UCP-LFAs) showed that the generated PGL−I and PGL-II trisaccharide neoglycoconjugates can be applied for the detection of anti M. leprae IgM antibodies in POC tests.  相似文献   
992.
993.
The patient‐centered care model supports patients actively engaging in their care. Typically this involves collecting patient‐reported outcomes and priorities that may not be part of the routine practice. There is a research gap related to whether there is time available within the routine orthopedic medical practice to collect patient‐centered data for immediate use without delaying the overall clinical processes or influencing patient clinical experiences. A time study was conducted to quantify the current patient processes at an orthopedic clinic, and a statistical simulation model was used to evaluate potential changes in patients’ clinical process if a patient‐centered survey were to be implemented. The proportion of simulated patients who would experience delays due to the survey, the durations of their delays, and the average duration of the patient process delay were recorded at each step in the clinical process. The results are presented in terms of the relationship between the time devoted to collecting data and the impact on the patient experience for various survey durations at various process points. This study demonstrates an approach to evaluate how introducing a patient priorities survey (for collecting both patient‐reported outcomes and priorities), which could be used in the same patient visit, might impact the clinical process and introduce process delays.  相似文献   
994.
After a straw‐fired power plant in Denmark had been in operation for 16 years with 93,815 hr operation, there was a need for overlay welding repair of the grate due to a decrease in wall thickness from erosion/corrosion. The grate consisted of 15Mo3 (Werkstoff nr. 1.5415) tubes where water/steam flows through, which were welded together with fins, and where one side faced the combustion zone coming into contact with the fuel (the side that required weld overlay). The water/steam temperature was 320°C and the surface metal temperature was estimated to be 350°C. However, there were difficulties when trying to overlay weld the grate as the weld pool was unstable. The microhardness measurements on cross‐sections of the tubes revealed a higher hardness of the tube facing the combustion zone compared to opposite the combustion zone. In addition, there was higher hardness adjacent to the combustion side than the steam/water side. Analysis of etched cross‐sections with light optical and scanning electron microscopy revealed the presence of acicular structures at the convex surface. Further analysis has been conducted with X‐ray diffraction and a LECO nitrogen analyser indicating the presence of iron nitrides. Reasons for their evolution and implications for the repair welding are discussed.  相似文献   
995.
996.
997.
998.
999.
Overbagged udders are commonly seen at dairy cow shows due to prolonged milking intervals. The aims of this study were to describe the prevalence of udder edema in dairy cows at shows as determined by sonography and to suggest a sonographic scoring system, which was evaluated for reproducibility and repeatability. At 4 highly competitive Swiss dairy cow shows, 319 cows of various breeds were examined. Sonographic scans—1 from each fore quarter and 1 from the rear, representing both hind quarters—were collected by 3 experienced veterinarians at defined positions predisposed to overbagging edema. Sonographic scans were scored with the aid of a newly suggested scoring system (score 0 = no edema, grade 1 = slight edema, grade 2 = moderate edema, grade 3 = severe edema). Further, 139 video sequences from behind while the cows were walking and the same number of photographs of the udder each from the left, right, and behind were selected. The photographs and video sequences were visually scored for different parameters as 0 = not present or 1 = present except for abduction, which was scored on a visual analog scale (0 = no abduction; 100 = maximal imaginable abduction). Visual scores were then compared with the sonographic scoring (Pearson's chi-squared). The prevalence of udder edema scores 1, 2, and 3 was 14.0, 6.5, and 2.3%, respectively. Interobserver reliability for objective sonographic scoring (κ = 0.815) and intraobserver agreement (κ = 0.90 and 0.85 for 2 different observers) was estimated as “almost perfect.” Interobserver agreements for visual parameters were κ = 0.40 or less except for teat shape (κ = 0.52). Classification of the videos resulted in better interobserver agreement; when rating hind limb abduction, Spearman correlation coefficient was 0.61, whereas κ = 0.61 for absence of udder movement. Udder movement and teat shape were significantly associated with the edema score. The higher inter- and intraobserver reliability of the sonographic edema scoring compared with the visual scoring system indicates that the newly suggested scoring system might be used in the future to objectively identify udder edema in cows at dairy shows.  相似文献   
1000.
Multibody System Dynamics - In multibody dynamics, the Euler parameters are often used for the numerical simulation of rigid body rotations because they lead to a relatively simple form of the...  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