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   159篇
  免费   11篇
  国内免费   3篇
电工技术   1篇
化学工业   30篇
金属工艺   1篇
机械仪表   2篇
建筑科学   13篇
能源动力   3篇
轻工业   21篇
水利工程   1篇
无线电   17篇
一般工业技术   36篇
冶金工业   20篇
自动化技术   28篇
  2023年   1篇
  2022年   4篇
  2020年   8篇
  2019年   2篇
  2018年   4篇
  2017年   3篇
  2016年   9篇
  2015年   6篇
  2014年   6篇
  2013年   12篇
  2012年   11篇
  2011年   10篇
  2010年   15篇
  2009年   10篇
  2008年   6篇
  2007年   5篇
  2006年   11篇
  2005年   5篇
  2004年   4篇
  2003年   5篇
  2002年   8篇
  2001年   4篇
  2000年   2篇
  1999年   5篇
  1998年   1篇
  1997年   1篇
  1996年   2篇
  1995年   4篇
  1994年   2篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1989年   1篇
  1988年   2篇
排序方式: 共有173条查询结果,搜索用时 16 毫秒
11.
Wind Gate     
Temporality came into play at a number of levels in this project. Programmatically a temporary, festival construction, the project worked with the reflective possibilities given in such structures. Contingent upon environmental and viewing conditions for its phenomenal character, the project also opened up critical issues about temporality as a "site" of perception and conception, and about the changes that take place in the latter as architectural works assume their place in the quotidian.  相似文献   
12.
Evidence for a short-range sex pheromone in female Maladera matrida beetle   总被引:3,自引:0,他引:3  
Laboratory studies with live and frozen Maladera matrida female and male beetles showed that males were attracted to chemical substances emanating from the females at dusk. Beetles exhibited sexual activity (including mating) at dusk towards frozen females but not towards frozen males. Frozen females that had been extracted with methanol together with either hexane or dichloromethane or with a mixture of all three solvents did not elicit male sexual activity. Activity was fully restored when a concentrate of the extract was applied to the previously extracted frozen females. Males also responded with vigorous sexual activity to frozen males to which female extract had been applied. Deterrent chemicals appear to be absent from the male body. Males exposed to females that had been frozen during the morning displayed weak sexual activity, indicating that females lack active semiochemicals. Differences between dusk and morning extracts were found with respect to more than 20 compounds, some of which were present in much higher concentrations at dusk than in the morning, while others were not detected in the morning extract. The active component(s) of the short-range sex pheromone of female M. matrida is (are) presumably to be found among these compounds.  相似文献   
13.
14.
15.
We examined 393 African American married couples assigned to (a) a culturally sensitive version of a widely disseminated relationship enhancement program (CS-PREP); (b) a similar version of the same program that also included a focus on prayer (PFP condition); or (c) an information-only control condition in which couples received a self-help version of the same program. Husbands averaged 40.5 years of age and wives averaged 38.9 years. We found a significant interaction between intervention and time of assessment, reflecting group differences in linear trends for the three conditions, with the two intervention conditions performing better than the control condition, and PFP producing superior outcomes to CS-PREP only for wives at post and marginally better results at 12-month follow-up. Results support continued exploration of the adjunctive use of prayer in the context of relationship enhancement programs where appropriate to make them more culturally sensitive. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
16.
Polycrystalline sample of (Na0.5Bi0.5)ZrO3 was prepared using a high-temperature solid-state reaction technique. XRD analysis indicated the formation of a single-phase orthorhombic structure. Dielectric study revealed the diffuse phase transition at 425 °C. AC impedance plots were used as tools to analyse the electrical behaviour of the sample as a function of frequency at different temperatures. The ac impedance studies revealed the presence of grain boundary effect at and above 350 °C. Complex impedance analysis indicated non-Debye type dielectric relaxation and negative temperature coefficient of resistance (NTCR) character of (Na0.5Bi0.5)ZrO3. AC conductivity data were used to evaluate the density of states at Fermi level and activation energy of the compound. DC electrical and thermal conductivities of grain and grain boundary have been assessed.  相似文献   
17.
18.
In this paper, we address a research lacuna in the area of human experience of, and interaction with, nature. We focus on women in an urbanized setting, exploring their actual and desired experiences of the natural world, using Singapore as a case study. Our intention is to contribute to both the evolving theoretical and empirical discussions on this subject. Based on data collected from focus group discussions and household questionnaires, we conclude that women's relationships with nature in Singapore are underscored by a strong inclination towards nurturing: teaching, tending and caring, in a way that is not as apparent in men's relationships with nature. Women's relationships with nature may also be conceptualized in terms of 'danger' and 'delight', a fine balance between ambivalent experiences of fear and enjoyment. In comparing results based on the Singapore context with those in Britain, sources of enjoyment appear to be similar, but the different social situations have resulted in different sources of fear. We conclude by putting forward some recommendations for planning and designing green areas that may enhance women's use and enjoyment of nature areas.  相似文献   
19.
Despite advances in cancer diagnosis and treatment, ovarian cancer remains one of the most fatal cancer types. The development of targeted nanoparticle imaging probes and therapeutics offers promising approaches for early detection and effective treatment of ovarian cancer. In this study, HER‐2 targeted magnetic iron oxide nanoparticles (IONPs) are developed by conjugating a high affinity and small size HER‐2 affibody that is labeled with a unique near infrared dye (NIR‐830) to the nanoparticles. Using a clinically relevant orthotopic human ovarian tumor xenograft model, it is shown that HER‐2 targeted IONPs are selectively delivered into both primary and disseminated ovarian tumors, enabling non‐invasive optical and MR imaging of the tumors as small as 1 mm in the peritoneal cavity. It is determined that HER‐2 targeted delivery of the IONPs is essential for specific and sensitive imaging of the HER‐2 positive tumor since we are unable to detect the imaging signal in the tumors following systemic delivery of non‐targeted IONPs into the mice bearing HER‐2 positive SKOV3 tumors. Furthermore, imaging signals and the IONPs are not detected in HER‐2 low expressing OVCAR3 tumors after systemic delivery of HER‐2 targeted‐IONPs. Since HER‐2 is expressed in a high percentage of ovarian cancers, the HER‐2 targeted dual imaging modality IONPs have potential for the development of novel targeted imaging and therapeutic nanoparticles for ovarian cancer detection, targeted drug delivery, and image‐guided therapy and surgery.  相似文献   
20.
The temperature profiles associated with the passage of self-propagating combustion waves during the synthesis of MoSi2 and Ti5Si3 were determined. From these profiles, kinetic analyses of the combustion synthesis process for these two silicides were made. The synthesis is associated with high heating rates: 1.3 × 104 and 4.9 × 104 K·s−1 for MoSi2 and Ti5Si3, respectively. The width of the combustion zone was determined as 1.3 and 1.8 mm for the silicides of Mo and Ti, respectively. The degree of conversion, η, and its spatial distribution and the conversion rate, ∂η/∂t, were determined. However, because of the inherent characteristics of wave propagation in MoSi2, only in the case of Ti5Si3 could the activation energy be calculated. An average value of 190 kJ μ mol1 was determined for titanium suicide.  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