全文获取类型
收费全文 | 24732篇 |
免费 | 1206篇 |
国内免费 | 656篇 |
专业分类
电工技术 | 2775篇 |
技术理论 | 10篇 |
综合类 | 2789篇 |
化学工业 | 2136篇 |
金属工艺 | 497篇 |
机械仪表 | 582篇 |
建筑科学 | 6036篇 |
矿业工程 | 2002篇 |
能源动力 | 1230篇 |
轻工业 | 842篇 |
水利工程 | 1657篇 |
石油天然气 | 1417篇 |
武器工业 | 29篇 |
无线电 | 425篇 |
一般工业技术 | 922篇 |
冶金工业 | 1881篇 |
原子能技术 | 56篇 |
自动化技术 | 1308篇 |
出版年
2024年 | 16篇 |
2023年 | 108篇 |
2022年 | 363篇 |
2021年 | 425篇 |
2020年 | 558篇 |
2019年 | 365篇 |
2018年 | 336篇 |
2017年 | 394篇 |
2016年 | 571篇 |
2015年 | 664篇 |
2014年 | 2320篇 |
2013年 | 1557篇 |
2012年 | 1964篇 |
2011年 | 2124篇 |
2010年 | 1838篇 |
2009年 | 1690篇 |
2008年 | 1333篇 |
2007年 | 1578篇 |
2006年 | 1414篇 |
2005年 | 1203篇 |
2004年 | 1059篇 |
2003年 | 952篇 |
2002年 | 847篇 |
2001年 | 617篇 |
2000年 | 557篇 |
1999年 | 419篇 |
1998年 | 273篇 |
1997年 | 233篇 |
1996年 | 172篇 |
1995年 | 128篇 |
1994年 | 108篇 |
1993年 | 60篇 |
1992年 | 62篇 |
1991年 | 64篇 |
1990年 | 37篇 |
1989年 | 27篇 |
1988年 | 28篇 |
1987年 | 13篇 |
1986年 | 10篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1979年 | 8篇 |
1963年 | 5篇 |
1960年 | 5篇 |
1958年 | 7篇 |
1957年 | 6篇 |
1956年 | 6篇 |
1955年 | 6篇 |
1954年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
给水管道在使用过程中很容易受到人为外力、管道材质、地下水、周围空气、土壤等因素的影响而腐蚀,影响了管道的使用质量和寿命,也带来较大的安全隐患。本文主要是从给水管道腐蚀原因出发,并探讨防护措施。 相似文献
2.
Arturo B. Soro Paul Whyte Declan J. Bolton Brijesh K. Tiwari 《Comprehensive Reviews in Food Science and Food Safety》2020,19(4):1353-1377
Campylobacteriosis is one of the most common bacterial infections worldwide causing economic costs. The high prevalence of Campylobacter spp. in poultry meat is a result of several contamination and cross‐contamination sources through the production chain. Moreover, survival mechanisms, such as biofilm formation, viable but nonculturable state, and antimicrobial resistance, enable its persistence during food processing. Therefore, mitigation strategies are necessary in order to avoid and/or inactivate Campylobacter at farm, abattoir, industry, and retail level. In this review, a number of potential strategies and novel technologies that could reduce the prevalence of Campylobacter in poultry meat have been identified and evaluated to provide a useful overview. At farm level for instance, biosecurity, bacteriocins, probiotics, feed and water additives, bacteriophages, and vaccination could potentially reduce colonization in chicken flocks. However, current technologies used in the chicken slaughter and processing industry may be less effective against this foodborne pathogen. Novel technologies and strategies such as cold plasma, ultraviolet light, high‐intensity light pulses, pulsed electric fields, antimicrobials, and modified atmosphere packaging are discussed in this review for reducing Campylobacter contamination. Although these measures have achieved promising results, most have not been integrated within processing operations due to a lack of knowledge or an unwillingness to implement these into existing processing systems. Furthermore, a combination of existing and novel strategies might be required to decrease the prevalence of this pathogen in poultry meat and enhance food safety. Therefore, further research will be essential to assess the effectiveness of all these strategies. 相似文献
3.
4.
5.
为了提高煤油气共生矿井油型气灾害治理的科学性,以黄陵二矿为例,采用现场测试、钻探取芯、跟踪观测、地质分析等多种方法,研究了采掘工作面煤层底板油型气分布特征、涌出规律和运移机理,并初步探讨了底板油型气体灾害防治措施。结果表明:底板油型气涌出点多位于底板砂岩储层上倾尖灭端和砂岩透镜体附近,呈现不连续区带状分布特征,涌出的油型气主要来自富县组砂岩层,涌出的动力主要为地层流体压力差,底板油型气通过地层中存在大量的断裂和裂缝、微裂缝系统进入采掘空间,采掘扰动是底板油型气异常涌出的工程诱导因素。建议加强油型气综合探查技术、油型气灾害预测预报技术、油型气综合抽采技术和智能化矿井建设等方面的研究。 相似文献
6.
近年来,我市因雷击而导致搅拌站系统瘫痪停产、影响工程进度的事件时有发生,在针对混凝土搅拌站配料秤的实际检定工作中,也常发现配料秤的称重传感器因雷击损坏而影响计量准确性。因此,对混凝土搅拌站防雷的研究具有重要意义。本文阐述了雷电对混凝土搅拌站的主要危害,分析了混凝土搅拌站常见的雷击原因及其防护措施,旨在引起生产方、安装方以及使用方对混凝土搅拌站防雷的共同重视。 相似文献
7.
为了给辉县景区减灾防灾提供地质依据,根据实际工程概况,研究了辉县部分景区地质灾害危险性预测评估及防治措施,预测评估了工程建设中、建设后可能引发或加剧地质灾害危险性,建设工程自身可能遭受已存在地质灾害危险性;评估了地质灾害危险性综合分区以及根据地质灾害危险性、防治难度和防治效益,对评估区适宜性作出评价,提出了防治地质灾害的措施和建议。 相似文献
8.
9.
This research supports the cross-modal correspondence between the shape of the bottle and consumers’ perception of sweetness and price using physical measures of beverage bottles. Images that add visual weight to the lower section of a package increase the perception of attributes associated with sweetness. In terms of price, the shape of the bottle is informative about its volume, which is the cue predictor of price. Through a within-subject experiment, we evaluated consumers’ perceptions of sweetness and price for a sample of 15 soft drink bottle silhouettes. These perceptions were correlated with the psychophysical characteristics of the silhouettes. Results reveal that sweetness has a negative correlation with height and the visual weight towards the bottom of the bottle. Instead, the price has a positive correlation with the area, width, height, lid, and variance of the bottle shape. Practical implications support having a package design that is consistent with product positioning and attributes. 相似文献
10.
Olga Filippova Yu Xiao Michael Rehm Jason Ingham 《Building Research & Information》2018,46(7):711-724
The marked increase in the awareness of earthquake risk following the Canterbury earthquakes in New Zealand offered a unique opportunity to investigate the economic effect of disaster-mitigation regulations on the commercial building stock. A difference-in-differences (DD) framework was used to determine whether earthquake risk has been capitalized into the property prices of buildings constructed prior to 1976, as a response to the national policy requiring assessment and strengthening (or demolition) of the existing earthquake-prone building stock. A negative externality is found in the policy announcement on affected (pre-1970s) office and retail buildings which caused office buildings to suffer a 12.5% stigma discount. However, retail properties were less impacted suffering a 2.3% stigma loss. The value of the commercial building stock has been affected by the policy. These findings provide policy-makers with timely evidence as to the economic effects of New Zealand’s earthquake-prone buildings policy. Facing losses in property value and financial responsibility for retrofitting their assets, building owners will be looking for a workable set of regulatory and non-regulatory incentives to encourage disaster risk management and protect the built environment. 相似文献