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   1496篇
  免费   80篇
  国内免费   2篇
电工技术   23篇
化学工业   489篇
金属工艺   37篇
机械仪表   43篇
建筑科学   59篇
矿业工程   1篇
能源动力   31篇
轻工业   96篇
水利工程   2篇
石油天然气   6篇
武器工业   1篇
无线电   77篇
一般工业技术   354篇
冶金工业   77篇
原子能技术   11篇
自动化技术   271篇
  2023年   11篇
  2022年   71篇
  2021年   87篇
  2020年   35篇
  2019年   45篇
  2018年   65篇
  2017年   52篇
  2016年   43篇
  2015年   64篇
  2014年   68篇
  2013年   111篇
  2012年   87篇
  2011年   96篇
  2010年   75篇
  2009年   75篇
  2008年   59篇
  2007年   72篇
  2006年   50篇
  2005年   28篇
  2004年   29篇
  2003年   22篇
  2002年   36篇
  2001年   10篇
  2000年   17篇
  1999年   6篇
  1998年   14篇
  1997年   15篇
  1996年   15篇
  1995年   10篇
  1994年   11篇
  1993年   18篇
  1992年   11篇
  1991年   6篇
  1989年   6篇
  1988年   8篇
  1987年   9篇
  1986年   8篇
  1985年   5篇
  1984年   7篇
  1983年   7篇
  1982年   4篇
  1981年   16篇
  1980年   11篇
  1979年   11篇
  1978年   6篇
  1977年   7篇
  1976年   11篇
  1975年   10篇
  1974年   4篇
  1973年   9篇
排序方式: 共有1578条查询结果,搜索用时 15 毫秒
991.
992.
ABSTRACT

The study explores the relation between participants’ level of self-criticism, self-reassurance, and eye gaze when looking at photographs of primary emotions. Participants completed The Forms of Self-Criticising/Attacking & Self-Reassuring Scale (FSCRS) and then a facial-emotion expression task while their eye movements were being recorded by an eye-tracker. The results indicate differences in people’s eye-gaze patterns when viewing facial-emotion expressions in relation to the level of self-criticism and self-reassurance. Specifically, participants with higher self-reassurance look more frequently at the eye region and less frequently at other facial areas and beyond the emotional faces. However, individuals with higher self-hatred look at the outside of the face more frequently than at the eyes area, and higher self-inadequacy predicted the individual would look more frequently at the eyes than at other facial areas. The results are important for understanding the role of self-criticism in relation to facial-emotion expressions and gazing, as self-criticism is a key underlying factor of all kinds of psychopathologies. Following further research, the results could be used to develop more objective diagnostics for self-criticism screening than the existing self-rating scales.  相似文献   
993.
The generalized spin-one-half Falicov-Kimball model with Hund and Hubbard coupling is used to examine effects of spin ordering on superconducting correlations in the strongly correlated electron and spin systems. It is found that the ferromagnetic spin clusters (lines, bands, domains) suppress the superconducting correlations in the d-wave channel, while the antiferromagnetic ones have the fully opposite effect. The enhancement of the superconducting correlations due to the antiferromagnetic spin ordering is by factor 3 in the axial striped phase and even by the factor 8 in the phase segregated phase.  相似文献   
994.
995.
996.
Although the debates about access to services of general interest have been at the core of the EU territorial cohesion discourse since the late 1990s, the impact of unequal accessibility to living conditions has yet be the subject of close inspection. The paper examines the relationship between the accessibility of services of general interest and demographic and socio‐economic conditions in a specific Czech region. The analysis reveals inter‐municipal disparities and identifies spatially excluded areas. Despite the negative association of insufficient access with education and depopulation characteristics, the results suggest that demographic and socio‐economic development stems from a more complex set of factors.  相似文献   
997.
The thermal conductivity of a brick block with internal cavities is studied using a steady-state experiment in semi-scale conditions. A system of two climatic chambers separated by a connecting tunnel for sample positioning is applied in the measurements. The brick block is provided with necessary temperature- and heat flux sensors, thermally insulated and placed in the tunnel between the climatic chambers, where different temperatures are set. After achieving steady-state heat fluxes on both surfaces of the brick block, the calculation of the thermal conductivity is done using the measured data. The obtained results represent valuable information for the practical application of the studied brick block in building practice.  相似文献   
998.
Surface sulfation and Eu3+ doping of 0.2–2 µm anatase aggregates prepared by precipitation significantly increased their porosity, specific surface, crystallinity and photocatalytic activity in phenol photo-mineralization. Such large, porous clusters of photocatalysts containing nanocrystals with well developed crystallinity which sediment more quickly than nanopowder suspensions are advantageous in water treatment applications. Sulfated anatase co-doped with Eu3+ exhibited the highest photoactivity. This is composed of well developed crystallites in the 31–55 nm size-range, with evident faceting. Although the investigated powders showed very weak photo-disinfectant activity against Gram-negative Escherichia coli rods, they exhibit moderate efficacy against Gram-positive bacterial strains of methicillin resistant Staphylococcus aureus (MRSA) and Enterococcus faecalis. The investigated powders, especially the Eu3+ doped ones, are highly active in elimination of the eukaryotic Candida albicans.  相似文献   
999.
Essential oils (EOs) have a long history as food preservatives and many advantages compared to synthetic preservatives. The major limitation of EOs as antimicrobial agents incorporated into a polymeric matrix is their low thermal stability and their high volatility from polymers. This study suggests a new methodology approach to bypass the key limitations of adding EOs into active packaging, as food preservatives. Antimicrobial active films based on linear low density polyethylene (LLDPE) and Montmorillonite (MMT) were produced by incorporating the EO thymol in a stepwise procedure. The production of the film composites, containing thymol, has been conducted, under a protocol of three stages: (1) production of a highly porous nano composite master batch; (2) impregnation of thymol into the master batch; and (3) cast film extrusion. Adding MMT incorporated together with a foaming agent at stage‐(1) increased significantly the heat stability of the EO during melt processing at stage‐(3). Finally, the film obtained showed a high antimicrobial activity. The results obtained have proven the synergistic interaction between MMT, foaming agent and thymol. As the MMT content in the film increased, the loss of EO in the processing decreased, leading to a natural antimicrobial film with improved antibacterial properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40564.  相似文献   
1000.
This work presents a model to predict the alkalinity, pH, and Langelier Saturation Index (LSI) in heterotrophic and H2-based autotrophic denitrification systems. The model can also be used to estimate the amount of acid, e.g. HCl, added to the influent (method 1) or the pH set point in the reactor (method 2: pH can be maintained stable by CO2-sparge using a pH-control loop) to prevent the pH from exceeding the optimal range for denitrification and to prevent precipitation from occurring. The model was tested with two pilot plants carrying out denitrification of groundwater with high hardness: a heterotrophic system using ethanol as the electron donor and an H2-based autotrophic system. The measured alkalinity, pH, and LSI were consistent with the model for both systems. This work also quantifies: (1) how the alkalinity and pH in Stage-1 significantly differ from those in Stage-2; (2) how the pH and LSI differ significantly in the two denitrification systems while the alkalinity increase is about the same; and (3) why CO2 addition is the preferred method for autotrophic system, while HCl addition is the preferred method for the heterotrophic system.  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