全文获取类型
收费全文 | 274篇 |
免费 | 26篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 96篇 |
金属工艺 | 2篇 |
机械仪表 | 9篇 |
建筑科学 | 19篇 |
能源动力 | 7篇 |
轻工业 | 47篇 |
水利工程 | 5篇 |
无线电 | 11篇 |
一般工业技术 | 47篇 |
冶金工业 | 26篇 |
原子能技术 | 3篇 |
自动化技术 | 25篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 20篇 |
2021年 | 34篇 |
2020年 | 15篇 |
2019年 | 10篇 |
2018年 | 13篇 |
2017年 | 11篇 |
2016年 | 7篇 |
2015年 | 9篇 |
2014年 | 19篇 |
2013年 | 8篇 |
2012年 | 18篇 |
2011年 | 19篇 |
2010年 | 18篇 |
2009年 | 16篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 12篇 |
2005年 | 7篇 |
2004年 | 10篇 |
2003年 | 6篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1980年 | 1篇 |
排序方式: 共有301条查询结果,搜索用时 15 毫秒
41.
Water Resources Management - The long-term success of water service reforms depends on sufficient revenues being collected from users to allow access to be extended and quality of service to be... 相似文献
42.
Eva Olivia Leontien Lantsoght Rutger T. Koekkoek Dick Hordijk Ane de Boer 《Structure and Infrastructure Engineering》2018,14(3):365-380
Proof load tests of bridges can be very useful for structures with a lack of information, or for structures of which the effect of material degradation is difficult to assess. Contrary to diagnostic load testing, proof load testing is not well-defined in current standards in terms of required load and analysis of measurements. The risk related to the high loads used in proof load testing requires standardisation for these tests. The paper highlights important considerations for proof load testing that may lead to the development of guidelines in the Netherlands, by illustrating a pilot study on the viaduct Zijlweg in the Netherlands. This reinforced concrete bridge rates too low in shear. Topics of interest are the required load that the bridge has to withstand to be approved by the load test and the interpretation of the measurements during the test to avoid permanent damage to the structure. These measurements were compared to the stop criteria from existing codes for buildings, to examine if recommendations for the use with bridges can be formulated. The final result of the test on this case study is that the capacity of the viaduct is proven to be sufficient for shear and bending moment. 相似文献
43.
44.
Deborah G. Martin Azadeh Hadizadeh Esfahani Olivia R. Williams Richard Kruger Joseph Pierce James DeFilippis 《Housing Studies》2020,35(3):395-414
AbstractDiscourses regarding homeownership in the United States emphasize housing as an economic investment. This focus fosters a number of problems, including inflated housing values, increased segregation, economic divisions, and the foreclosure crisis. Community land trusts (CLTs) put land in a non-profit trust to keep it affordable long-term. We examine CLTs as affordable housing organizations where individual residents own homes in the trust and lease the land underneath from the CLT. Interviews of CLT homeowners and staff in Minnesota, USA, show that the use value of CLT housing creates opportunities for different life choices. CLT homeowners cite stability and autonomy as the primary benefits of homeownership. They expressed newfound confidence and freedom to pursue personal goals and live less restricted lives after moving into CLT homes, a finding also emphasized by CLT staff. Limited equity housing such as CLTs can both reinforce dominant meanings of homeownership as providing security and autonomy, while also fostering access and affordability for low-income residents. 相似文献
45.
Marivee Borges-Rodriguez Corbin A. Shields Olivia K. Travis Robert W. Tramel Cedar H. Baik Chelsea A. Giachelli Geilda A. Tardo Jan Michael Williams Denise C. Cornelius 《International journal of molecular sciences》2021,22(19)
Platelets, cellular mediators of thrombosis, are activated during sepsis and are increasingly recognized as mediators of the immune response. Platelet activation is significantly increased in sepsis patients compared to ICU control patients. Despite this correlation, the role of activated platelets in contributing to sepsis pathophysiology remains unclear. We previously demonstrated NOD-like receptor protein 3 inflammasome (NLRP3) inflammasome activation in sepsis-induced platelets from cecal-ligation puncture (CLP) rats. Activated platelets were associated with increased pulmonary edema and glomerular injury in CLP vs. SHAM controls. In this study, we investigated whether inhibition of platelet activation would attenuate NLRP3 activation and renal and pulmonary injury in response to CLP. CLP was performed in male and female Sprague Dawley (SD) rats (n = 10/group) to induce abdominal sepsis and SHAM rats served as controls. A subset of CLP animals was treated with Clopidogrel (10 mg/kg/day, CLP + CLOP) to inhibit platelet activation. At 72 h post-CLP, platelet activation and NLRP3 inflammasome assembly were evaluated, IL-1β and IL-18 were measured in plasma, and tissues, renal and pulmonary pathology, and renal function were assessed. Activated platelets were 7.8 ± 3.6% in Sham, 22 ± 6% in CLP and significantly decreased to 14.5 ± 0.6% in CLP + CLOP (n = 8–10/group, p < 0.05). NLRP3 inflammasome assembly was inhibited in platelets of CLP + CLOP animals vs. CLP. Significant increases in plasma and kidney IL-1β and IL-18 in response to CLP were decreased with Clopidogrel treatment. Renal injury, but not lung histology or renal function was improved in CLP + CLOP vs. CLP. These data provide evidence that activated platelets may contribute to sepsis-induced renal injury, possibly via NLRP3 activation in platelets. Platelets may be a therapeutic target to decrease renal injury in septic patients. 相似文献
46.
47.
Faces and objects of expertise compete for early perceptual processes and holistic processing resources (Gauthier, Curran, Curby, & Collins, 2003). Here, we examined the nature of interference on holistic face processing in working memory by comparing how various types of loads affect selective attention to parts of face composites. In dual tasks, all loads impaired overall performance on face judgment compared with no load. However, a face load reduced holistic face processing (Experiment 1) whereas an object load did not, regardless of expertise (Experiments 2 and 3). Also, 2 types of faces produced asymmetrical interference on each other (Experiment 4), refuting the hypothesis that any faces would produce equal interference. Thus, the interference on holistic face processing in working memory does not depend on overlap in expertise or face processing, but may be modulated by limitations in encoding or maintenance of highly similar representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
48.
Previous research shows that factors such as time, temperature, nutritional make‐up of a liquid, and type of thickening agent can significantly alter the resulting thickness of liquids. This study sought to determine the effect of three distinct mixing methods on the resulting thickness of ready to feed infant formulas mixed to Mildly and Moderately Thick (International Dysphagia Diet Standardization Initiative [IDDSI] Levels 2 and 3) with three different thickening agents. Eight commercially available infant formulas were mixed with three different thickening agents by three different mixing methods. The IDDSI Syringe Flow Test was used to categorize the thickened formulas. Chi square analyses were completed to determine the impact of mixing method on the thickened formulas. The majority (94%) of thickened formula combinations prepared to a target Mildly Thick consistency produced thickened formula that was thinner or thicker than the target. In contrast, the majority (76%) of thickened formula combinations prepared to a target Moderately Thick (IDDSI Level 3) consistency produced thickened formula that was equivalent to the target consistency. A statistically significant relationship was found between mixing methods and resulting IDDSI category for samples mixed to a target of Moderately Thick. The thickening agent and method of mixing must be considered carefully when preparing infant formulas to Mildly and Moderately Thick target IDDSI categories. Based on results of this study, it is recommended that providers utilize a clinical testing method, such as the IDDSI Syringe Flow Test, when attempting to create a Mildly Thick formula consistency. 相似文献
49.
Kanakala R Escudero R Rojas-George G Ramisetty M Graeve OA 《ACS applied materials & interfaces》2011,3(4):1093-1100
We present an analysis of the combustion synthesis mechanisms for the preparation of hexaboride materials using three compounds as model systems: EuB(6), YbB(6), and YB(6). These three hexaborides were chosen because of the differences in ionic radii between Eu(3+), Yb(3+), and Y(3+), which is a factor in their stability. The powders were prepared using metal nitrates, carbohydrazide, and two different boron precursor powders. The resulting materials were analyzed by X-ray diffraction, which showed that combustion synthesis is effective for the synthesis of EuB(6), since the Eu(3+) ion has an ionic radius greater than ~1 ?. The synthesis of YbB(6) and YB(6) is not as effective because of the small size of the Yb(3+) and Y(3+) ions, making the hexaborides of these metals less stable and resulting in the synthesis of borates due to the presence of oxygen during the combustion process. Scanning electron microscopy and dynamic light scattering of the EuB(6) powders shows that the particle size of the hexaboride product is dependent on the particle size of the boron precursor. The magnetic susceptibility of our EuB(6) powders manifests irreversible behavior at low applied fields, which disappears at higher fields. This behavior can be attributed to the increase in size and number of magnetic polarons with increasing magnetic field. 相似文献
50.
Córdova MO Flores Ramírez CI Bejarano BV Arroyo Razo GA Pérez Flores FJ Tellez VC Ruvalcaba RM 《International journal of molecular sciences》2011,12(12):8575-8580
In this work, the results of a study comparing the use of irradiation from different regions of the infrared spectrum for the promotion of several organic reactions, are presented and discussed. This use of eco-conditions provides a green approach to chemical synthesis. A set of ten different organic reactions were evaluated, including the Knoevenagel, Hantzsch, Biginelli and Meldrum reactions. It is important to highlight the use of a commercial device that produces infrared irradiation in the near infrared region and its distribution by convection providing heating uniformity, significantly reducing reaction times, achieving good yields and proceeding in the absence of solvent. It is also worth noting that a variety of different reactions may be performed at the same time. Finally, the products obtained were identified using TLC, together with corresponding MS-data, complementarily in comparison of NMR (1)H and (13)C data with literature information. 相似文献