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   227篇
  免费   9篇
  国内免费   2篇
电工技术   16篇
综合类   12篇
化学工业   34篇
金属工艺   7篇
机械仪表   6篇
建筑科学   18篇
能源动力   4篇
轻工业   9篇
水利工程   1篇
石油天然气   2篇
无线电   32篇
一般工业技术   48篇
冶金工业   29篇
原子能技术   4篇
自动化技术   16篇
  2024年   1篇
  2023年   1篇
  2021年   5篇
  2020年   3篇
  2019年   8篇
  2018年   1篇
  2017年   6篇
  2016年   4篇
  2015年   2篇
  2014年   7篇
  2013年   12篇
  2012年   16篇
  2011年   35篇
  2010年   12篇
  2009年   9篇
  2008年   10篇
  2007年   11篇
  2006年   12篇
  2005年   7篇
  2004年   5篇
  2003年   3篇
  2002年   10篇
  2001年   1篇
  2000年   4篇
  1999年   9篇
  1998年   7篇
  1997年   6篇
  1996年   9篇
  1995年   3篇
  1994年   8篇
  1993年   2篇
  1992年   2篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1980年   1篇
  1976年   1篇
  1964年   1篇
排序方式: 共有238条查询结果,搜索用时 31 毫秒
1.
Colorectal cancer (CRC) is the third most deadly cancer worldwide, and inflammatory bowel disease (IBD) is one of the critical factors in CRC carcinogenesis. IBD is responsible for an unphysiological and sustained chronic inflammation environment favoring the transformation. MicroRNAs (miRNAs) belong to a class of highly conserved short single-stranded segments (18–25 nucleotides) non-coding RNA and have been extensively discussed in both CRC and IBD. However, the role of miRNAs in the development of colitis-associated CRC (CAC) is less clear. The aim of this review is to summarize the major upregulated (miR-18a, miR-19a, miR-21, miR-31, miR-155 and miR-214) and downregulated (miR-124, miR-193a-3p and miR-139-5p) miRNAs in CAC, and their roles in genes’ expression modulation in chronic colonic-inflammation-induced carcinogenesis, including programmed cell-death pathways. These miRNAs dysregulation could be applied for early CAC diagnosis, to predict therapy efficacy and for precision treatment.  相似文献   
2.
用Nardini-Brebbia边界元法计算了动载荷下的应力强度因子,与解析解及有限元解相比较,效果较好。最后对计算结果进行了分析讨论。  相似文献   
3.
We have solved both steady state and transient problems on the biofiltration of toluene vapor. The effect of inlet toluene concentration and inlet gas-flow rate on the removal rate of toluene and the elimination capacity of a lab-scale biofilter has been investigated. In this study, the effectiveness factor was a function of pollutant concentration. The dynamic solutions show good agreement with experimental results. At an inlet toluene concentration of 100 ppm, the diffusion of toluene into biofilm was obviously a rate determining step. Above 200 ppm, however, biofilm already showed full activity. The steady-state simulation confirmed that the change of elimination capacity obtained by increasing only inlet toluene concentration was the same as that obtained by increasing only flow rate of contaminated air. The maximum possible performance is about 20 g/m3h with no addition of nutrients.  相似文献   
4.
Partnering has been advocated for use in construction as a project-delivery approach to curb dispute and enable a cooperative contracting environment. Successful construction partnering is perceived to derive benefits to both developers and contractors. In view of significant implications to successful project delivery, there has been a surge of research and studies on construction partnering. These studies typically focus on the partnering process as well as the identification of critical success factors. Among the various success factors that underpin partnering success, establishing trust among partners is considered the most important. Moreover, skeptics have been swift to point out that establishing trust in construction is daunting. A better understanding of the role of trust and its manifestation in partnering efforts is therefore of both academic and practical value. In this study, motivating trust in construction partnering is described within the classic framework of “the prisoner’s dilemma,” which suggests the trust cycle can be kick-started if construction partners put cooperation before competition and self-interest. This paper reports a study that is designed to suggest a suitable candidate for the trust initiator. As such, the critical trust factors for two groups of construction partners in Hong Kong—developers/consultants and contractors—are first identified. It is found that “performance” and “permeability” of partners are the two most critical trust factors. “Performance” describes the partner’s competence and problem-solving ability as perceived by their counterpart. “Permeability” reflects the partner’s openness in sharing information. The result of a multiple-regression analysis further suggests that the contractor is in a position to initiate trust through competent performance and maintaining effective communication with the client. In this manner, the trust cycle can expand with reciprocal trustworthiness from the client.  相似文献   
5.
Pineapple pomace fibre (PF, containing 70.2% total dietary fibre) can be added to increase dietary fibre of wheat bread. This study was performed to evaluate effects of PF added at 0, 5 or 10% (wheat flour‐basis) on physicochemical properties of the composite flour (wheat flour as the control, CPF‐5 and CPF‐10, respectively) and its dough, to evaluate consumer acceptance of CPF breads and to identify factors affecting willingness to purchase of CPF breads. Incorporating PF affected rheological and pasting properties of CPF. Water‐ and oil‐holding capacity of CPF increased (< 0.05) as PF levels increased. Bread made with CPF‐5 was more acceptable than that with CPF‐10; however, it was not significantly different from the control, having similar specific volume and texture, but having about three times higher total dietary fibre than the control (4.4% vs. 1.5%). Product label and health benefit information potentially affected consumers' willingness to purchase of fibre‐enriched bread.  相似文献   
6.
随着汽车电子设备的不断增多,汽车系统设计复杂度也在不断提升。为应对日趋复杂的汽车车门控制设计,本文介绍了安森美半导体提供的器件选型及系统解决方案。  相似文献   
7.
In response to the increasing public concern over the effects of construction waste on the environment, a performance assessment system has been designed to provide an instant, online assessment of how well a construction site performs environmentally, e.g. measuring the level of pollution generated from a construction site. Through the use of both Internet and database technologies, it is possible to collect and present data that are essential for environmental management online. To achieve this, a set of environmental performance parameters was derived through a postal questionnaire survey and interviews with experts in the field. A conceptual framework was developed, of which the key components were: template, knowledge base, output data and benchmark group. In combination, these factors provide a system that enables speedy assessment and effective management of environmental performance on construction sites, hence prompt decisions can be made and corrective actions can be taken before potential hazards turn into real disasters.  相似文献   
8.
An acidogenic reactor with a 0.5-L working volume and a methanogenic digester with a 5-L of working volume were operated for 150 days on a continuous mode to investigate the structure of a microbial community during food wastewater treatment. During the steady state of anaerobic digestion, volatile solids (VS) removal efficiency in the pilot plant was approximately 65%. The bacterial population was higher than any other methanogens detected during the entire anaerobic process and treatment of raw food wastewater. Methanomicrobiales (MMB), Methanosarcinales (MSL), and Methanobacteriales (MBT) were detected during digestion. The methanogenic population present in the acidogenic reactor was directly affected by the archaeal community in raw food wastewater. However, the shift of microbial community in the methanogenic digester was relatively gradual. The performance of methanogenic digester might be more related to the change of microbial metabolism affected by the physicochemical properties of the input substrate.  相似文献   
9.
台阶深孔微差爆破是一种大规模、快速的土石方施工方法。本文就连云港庙岭开山填海建港工程中,台阶深孔微差爆破技术的应用情况、多年来的施工经验体会作了介绍,并对一些爆破理论进行了讨论。另外,就爆破工作在管理上存在的问题和改善管理后取得的效果作了分析。  相似文献   
10.
Hydrogen peroxide (H2O2) is one of essential oxygen metabolites in living organisms, but is generated in large amounts during inflammatory responses. Therefore, H2O2 has great potential as diagnostic and therapeutic markers of several inflammatory and life‐threatening diseases. Here, chemiluminescent and antioxidant micelles are reported as novel theranostic agents for H2O2‐associated inflammatory diseases. The chemiluminescent micelles composed of amphiphilic block copolymer Pluronic F‐127, hydroxybenzyl alcohol‐incorporated copolyoxalate (HPOX) and fluorescent dyes perform peroxalate chemiluminescence reactions to detect H2O2 as low as 100 nM and image H2O2 generated in inflamed mouse ankles. The micelles encapsulating HPOX reduce the generation of reactive oxygen species in lipopolysaccharide (LPS)‐activated macrophages by scavenging overproduced H2O2 and releasing antioxidant hydroxybenzyl alcohol (HBA). They also exert inhibitory effects on H2O2‐induced apoptosis. HPOX‐based chemiluminescent and antioxidant micelles have great potential as a theranostic agent for H2O2‐associated inflammatory diseases.  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