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   180篇
  免费   9篇
  国内免费   4篇
化学工业   33篇
金属工艺   3篇
机械仪表   4篇
建筑科学   4篇
能源动力   12篇
轻工业   19篇
水利工程   2篇
石油天然气   3篇
无线电   34篇
一般工业技术   43篇
冶金工业   18篇
原子能技术   2篇
自动化技术   16篇
  2023年   4篇
  2022年   6篇
  2021年   23篇
  2020年   12篇
  2019年   8篇
  2018年   13篇
  2017年   9篇
  2016年   21篇
  2015年   5篇
  2014年   6篇
  2013年   8篇
  2012年   4篇
  2011年   6篇
  2010年   8篇
  2009年   5篇
  2008年   6篇
  2007年   4篇
  2006年   3篇
  2005年   4篇
  2004年   3篇
  2003年   2篇
  2002年   3篇
  2001年   3篇
  2000年   4篇
  1999年   1篇
  1998年   4篇
  1997年   3篇
  1996年   2篇
  1995年   3篇
  1993年   3篇
  1991年   2篇
  1990年   1篇
  1988年   2篇
  1984年   1篇
  1976年   1篇
排序方式: 共有193条查询结果,搜索用时 312 毫秒
61.
Job insecurity research has focused primarily on attitudinal (e.g., job satisfaction), behavioral (e.g., employee turnover), and health outcomes. Moreover, research in the area of workplace safety has largely focused on ergonomic factors and personnel selection and training as primary antecedents of safety. Two cross-sectional structural equational modeling analyses and 1 longitudinal regression analysis of 237 food-processing plant employees unite these 2 disparate areas of research by exploring the relatively uncharted relationship between job insecurity and safety outcomes. Results indicate that employees who report high perceptions of job insecurity exhibit decreased safety motivation and compliance, which in turn are related to higher levels of workplace injuries and accidents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
62.
The novel coronavirus disease, coined as COVID-19, is a murderous and infectious disease initiated from Wuhan, China. This killer disease has taken a large number of lives around the world and its dynamics could not be controlled so far. In this article, the spatio-temporal compartmental epidemic model of the novel disease with advection and diffusion process is projected and analyzed. To counteract these types of diseases or restrict their spread, mankind depends upon mathematical modeling and medicine to reduce, alleviate, and anticipate the behavior of disease dynamics. The existence and uniqueness of the solution for the proposed system are investigated. Also, the solution to the considered system is made possible in a well-known functions space. For this purpose, a Banach space of function is chosen and the solutions are optimized in the closed and convex subset of the space. The essential explicit estimates for the solutions are investigated for the associated auxiliary data. The numerical solution and its analysis are the crux of this study. Moreover, the consistency, stability, and positivity are the indispensable and core properties of the compartmental models that a numerical design must possess. To this end, a nonstandard finite difference numerical scheme is developed to find the numerical solutions which preserve the structural properties of the continuous system. The M-matrix theory is applied to prove the positivity of the design. The results for the consistency and stability of the design are also presented in this study. The plausibility of the projected scheme is indicated by an appropriate example. Computer simulations are also exhibited to conclude the results.  相似文献   
63.
Mounting‐up economic losses to annual crops yield due to micronutrient deficiency, fertiliser inefficiency and increasing microbial invasions (e.g. Xanthomonas cempestri attack on tomatoes) are needed to be solved via nano‐biotechnology. So keeping this in view, the authors’ current study presents the new horizon in the field of nano‐fertiliser with highly nutritive and preservative effect of green fabricated zinc oxide‐nanostructures (ZnO‐NSs) during Lycopersicum esculentum (tomato) growth dynamics. ZnO‐NS prepared via green chemistry possesses highly homogenous crystalline structures well‐characterised through ultraviolet and visible spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction and scanning electron microscope. The ZnO‐NS average size was found as small as 18 nm having a crystallite size of 5 nm. L. esculentum were grown in different concentrations of ZnO‐NS to examine the different morphological parameters includes time of seed germination, germination percentage, the number of plant leaves, the height of the plant, average number of branches, days count for flowering and fruiting time period along with fruit quantity. Promising results clearly predict that bio‐fabricated ZnO‐NS at optimum concentration resulted as growth booster and dramatically triggered the plant yield.Inspec keywords: zinc compounds, II‐VI semiconductors, wide band gap semiconductors, nanostructured materials, nanofabrication, ultraviolet spectra, visible spectra, Fourier transform infrared spectra, X‐ray diffraction, scanning electron microscopy, crystallites, biomedical materials, nanomedicineOther keywords: ZnO‐nanofertiliser, green chemistry, boosted growth dynamics, L. esculentum, mounting‐up economic losses, micronutrient deficiency, fertiliser inefficiency, microbial invasions, Xanthomonas cempestri, nanobiotechnology, zinc oxide‐nanostructures, Lycopersicum esculentum, high‐homogenous crystalline structures, ultraviolet spectroscopy, visible spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, crystallite size, morphological parameters, seed germination, germination percentage, plant leaves, ZnO  相似文献   
64.
This paper presents a scheme for ranking of spelling error corrections for Urdu. Conventionally spell-checking techniques do not provide any explicit ranking mechanism. Ranking is either implicit in the correction algorithm or corrections are not ranked at all. The research presented in this paper shows that for Urdu, phonetic similarity between the corrections and the erroneous word can serve as a useful parameter for ranking the corrections. This combined with a new technique Shapex that uses visual similarity of characters for ranking gives an improvement of 23% in the accuracy of the one-best match compared to the result obtained when the ranking is done on the basis of word frequencies only.
Sarmad HussainEmail:
  相似文献   
65.
This research reconciled disparate findings regarding the relationship between job insecurity and safety by examining organizational safety climate as a potential moderator. It was predicted that a strong organizational safety climate would attenuate the negative effects of job insecurity on self-reported safety outcomes such as safety knowledge, safety compliance, accidents, and injuries. Data collected from 136 manufacturing employees were consistent with these predictions. Results are discussed in light of escalating interest in how organizational factors can affect employee safety. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
66.
Naseem R  Tahir SS 《Water research》2001,35(16):3982-3986
The ability of bentonite clay to remove Pb(II) from aqueous solutions and from nitric acid, hydrochloric acid and perchloric acid solutions (1.0-1 x 10(-5)) has been studied at different optimized conditions of concentrations, amount of adsorbent, temperature, concentration of electrolyte and pH. Maximum adsorption of Pb(II), i.e. > 98% has been achieved in aqueous solutions, while 86% is achieved from 1.0 x 10(-5) M HCl using 0.5 g of bentonite. The adsorption decreases by increasing the concentration of electrolytes. Flame atomic absorption spectrometer was used for measuring lead concentration. Isotherm analysis of adsorption data obtained at 25 degrees C, 30 degrees C, 40 degrees C and 50 degrees C showed that the adsorption pattern of lead on bentonite followed the langmuir isotherm and freundlich isotherm, respectively. DeltaH(o) and deltaS(o) were calculated from the slope and intercept of ln K(D) vs. I/T plots.  相似文献   
67.
Benzoins are selectively oxidized to benzils in the presence of covalently anchored metal complexes onto silica by stirring in toluene at 100 °C in air atmosphere. Silica functionalized metal complexes have been prepared by the complexation of organically modified silica (imine) with Pd(OAc)2 (Cat 1), Co(OAc)2 (Cat 2) and Ni(OAc)2 (Cat 3). Cat 1, 2 and 3 have been characterized by FTIR, thermal analysis and AAS analysis. Cat 1 was found to be most active, stable and recyclable under the reaction conditions. It was also characterized by SEM and TEM.  相似文献   
68.
The main objective of this research was to identify factors that affected worker productivity, occupational health and safety in selected industries in a developing country. Fifty production managers participated in the study. Fifty-four percent of the managers reported hot environmental conditions, 28% a noisy environment, and 26% a lack of resources and facilities. Managers received worker complaints of fatigue, back pain, upper-body pain, hand and wrist pain and headaches. Management (88%) acknowledged not having knowledge or access to ergonomics information. Ninety-four percent of the companies did not carry out ergonomic assessments. A significant correlation (p<0.01) was found among productivity indicators and health and organizational attributes. Lack of skills in ergonomics and training, communication and resources are believed to be some of the factors contributing to the poor ergonomic conditions and consequent loss of worker productivity and reduced health and safety in these industries.  相似文献   
69.
The influence of autoclaved fungal materials such as culture filtrate, freeze-dried mycelium (FDM), mycelium suspension, and spore suspension (SS) on the growth, morphogenesis, and carvone production of spearmint (Mentha spicata L.) plants was studied. Fungal materials were either applied as a drench or spray on the plants. Spearmint plants (cv. “294099”) drenched with SS (1 × 108 spores/ml) of Trichoderma reesei showed no significant differences in leaf numbers, root numbers, or shoot numbers compared with nontreated controls. However, significantly higher fresh weights and carvone levels were observed in plants drenched with T. reesei SS compared with the untreated controls. Fungal materials derived from Aspergillus sp., Fusarium graminearum, F. sporotrichoides, Penicillium sp., P. acculeatum, Rhizopus oryzae, and T. reesei were sprayed on spearmint foliage. F. graminearum, F. sporotrichoides, or R. oryzae elicited no enhanced growth, morphogenesis, or secondary metabolism responses. The best growth and morphogenesis responses were obtained employing Aspergillus sp., Penicillium sp., or T. reesei foliar sprays. For example, spearmint cv. “557807” plants sprayed with 100 mg/l FDM T. reesei isolate NRRL 11460 C30 stimulated higher fresh weights (75%), shoot numbers (39%), leaf numbers (57%), and root numbers (108%) compared with untreated plants. This effect was not dose-dependent because similar growth and morphogenesis responses were obtained by testing 10, 100, or 1000 mg/l FDM concentrations. Carvone levels in fungal-treated foliar-sprayed plants were comparable to nontreated controls. However, total carvone levels per plant were higher in fungal-treated plants because of their increased fresh weight.Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable.  相似文献   
70.
The circuit boards of many mixed-signal and digital systems are now dominated by individually placed discrete passive (DP) components. This article looks at thin-film integrated passives (IPs) as an alternative to DPs in the effort to save board space and improve electrical performance and system reliability. Integrated passive components have been utilized successfully with ceramic substrate technology for over 50 years in the form of thick-film resistive and dielectric firable pastes. However, this considerable infrastructure cannot be transferred to FR4 and flex substrates due to the high firing temperatures required, and these board materials make up the vast majority of interconnect substrates, in consumer and commercial systems. Mmat has been lacking is thin-film IP materials and fabrication processes that are compatible with organic boards  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