全文获取类型
收费全文 | 63974篇 |
免费 | 5875篇 |
国内免费 | 2618篇 |
专业分类
电工技术 | 12423篇 |
技术理论 | 8篇 |
综合类 | 4619篇 |
化学工业 | 4799篇 |
金属工艺 | 1792篇 |
机械仪表 | 1971篇 |
建筑科学 | 11416篇 |
矿业工程 | 4210篇 |
能源动力 | 1723篇 |
轻工业 | 5393篇 |
水利工程 | 4496篇 |
石油天然气 | 2992篇 |
武器工业 | 507篇 |
无线电 | 3176篇 |
一般工业技术 | 3667篇 |
冶金工业 | 2215篇 |
原子能技术 | 1332篇 |
自动化技术 | 5728篇 |
出版年
2024年 | 250篇 |
2023年 | 678篇 |
2022年 | 1583篇 |
2021年 | 2003篇 |
2020年 | 1979篇 |
2019年 | 1397篇 |
2018年 | 1357篇 |
2017年 | 1699篇 |
2016年 | 1998篇 |
2015年 | 2205篇 |
2014年 | 5117篇 |
2013年 | 3690篇 |
2012年 | 5272篇 |
2011年 | 5365篇 |
2010年 | 4116篇 |
2009年 | 4091篇 |
2008年 | 3703篇 |
2007年 | 4518篇 |
2006年 | 4148篇 |
2005年 | 3338篇 |
2004年 | 2696篇 |
2003年 | 2493篇 |
2002年 | 1988篇 |
2001年 | 1615篇 |
2000年 | 1333篇 |
1999年 | 1003篇 |
1998年 | 596篇 |
1997年 | 494篇 |
1996年 | 395篇 |
1995年 | 346篇 |
1994年 | 231篇 |
1993年 | 162篇 |
1992年 | 121篇 |
1991年 | 94篇 |
1990年 | 68篇 |
1989年 | 59篇 |
1988年 | 74篇 |
1987年 | 30篇 |
1986年 | 26篇 |
1985年 | 30篇 |
1984年 | 32篇 |
1983年 | 16篇 |
1982年 | 7篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1973年 | 3篇 |
1959年 | 7篇 |
1951年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
1.
2.
3.
文章通过对黑龙江省高效节水现状,存在问题的分析,结合黑龙江省高效节水发展的支撑能力,阐述黑龙江省节水增粮目标、任务及总体布局,为黑龙江省2012—2015年节水增粮实施提供依据。 相似文献
4.
从电焊机自身电气特点及建筑工地工作环境入手,探讨电焊机安全技术的实施方法。分析电焊机安全隐患及事故的分类以及电焊机在使用过程中产生危险的原因。介绍电焊机在安装以及作业过程中的安全措施。 相似文献
5.
Health information technology (IT) is a promising way to achieve safer medication management in the delivery of healthcare. However, human factors/ergonomics dictates that in order to make the complex, cognitive work of healthcare delivery safer, health IT must properly support human cognition. This means, for example, that new health IT must reduce, not increase, workload during safety-critical tasks. The present study was the first to quantitatively assess the short- and long-term impact of bar coded medication administration (BCMA) IT on nurses' mental workload as well as on perceived medication safety. One-hundred seventy registered nurses across 3 dissimilar clinical units at an academic, freestanding pediatric hospital in the Midwest US participated in surveys administered before, 3 months after, and 12 months after the hospital implemented BCMA. Nurses rated their external mental workload (interruptions, divided attention, being rushed) and internal mental workload (concentration, mental effort) during medication administration tasks as well as the likelihood of each of three medication safety events: medication administration errors, medication errors on the clinical unit, and clinical unit-level adverse drug events. Clinical unit differences were assessed. Findings generally confirmed the hypothesis that external but not internal mental workload was associated with the perceived likelihood of a medication safety event. Comparisons of mental workload from pre- to post-BCMA revealed statistically significant changes in the critical care unit only. Medication safety appeared to improve over the long term in the hematology/oncology unit only. In the critical care and medical/surgical units, medication safety exhibited short-term improvements that were eliminated over time. Changes in mental workload and medication safety, two classically microergonomic constructs, were deeply embedded in macroergonomic phenomena. These included the fit between the BCMA system and the nature of nursing work, the process of BCMA implementation, and BCMA interactions with concurrent changes occurring in the hospital. Findings raise questions about achieving sustainable performance improvement with health IT as well as the balance between micro- and macroergonomic approaches to studying technology change.Relevance to industryDesigners must consider how technology changes cognitive work, including mental workload. Hospitals and other implementers of technology must ensure that new technology fits its users, their tasks, and the context of use, which may entail tailoring implementation, for example, to specific clinical units. Evaluators must look over time to assess both changes in cognitive work and implementation issues. Healthcare practitioners must also recognize that new technology means a complex transformation to an already complex sociotechnical system, which calls for a macroergonomic approach to design and analysis. 相似文献
6.
《Food Control》2015
This study aims to assess the degree of HACCP implementation in small business butcher shops and understand which factors most influence butchers' intention to fully implement it, through the application of the Theory of Planned Behaviour. One hundred and one butchers managing or owning small butcher's responded to the interview regarding their Attitudes, Subjective Norm, Perceived Behavioural Control, Personal Norm, and Knowledge with regard to their Intention to fully implement a HACCP system in their shops. Before the interviews, a certified veterinarian visited all the shops. Visits included an inspection of the establishments using the Official Portuguese Control Plan checklist for meat retailers. Conformance level measured past performance regarding food safety practices. Based on past performance, butchers were divided into “high performers” and “low performers”. “High performers” yielded high values of Attitude and Intention towards the Behaviour. For these, Attitude and Personal Norm emerge as predictors of the Intention to fully implement a HACCP system. For “low performers”, Personal Norm was the strongest predictor of Intention, with results pointing to the need for an intervention from the authorities to promote increased conformance to food safety practices. For both groups, neither Social Norm nor Perceived Behavioural Control acted as significant predictors of Intention. 相似文献
8.
9.
A double optimal projection method that involves projections for intra-cluster and inter-cluster dimensionality reduction are proposed for video fingerprinting. The video is initially set as a graph with frames as its vertices in a high-dimensional space. A similarity measure that can compute the weights of the edges is then proposed. Subsequently, the video frames are partitioned into different clusters based on the graph model. Double optimal projection is used to explore the optimal mapping points in a low-dimensional space to reduce the video dimensions. The statistics and geometrical fingerprints are generated to determine whether a query video is copied from one of the videos in the database. During matching, the video can be roughly matched by utilizing the statistics fingerprint. Further matching is thereafter performed in the corresponding group using geometrical fingerprints. Experimental results show the good performance of the proposed video fingerprinting method in robustness and discrimination. 相似文献
10.
Nilesh P. Vanikar Shantipal S. Ohol Saeede Goldar 《International Journal of Cast Metals Research》2018,31(4):249-259
Bottom pour ladles with stopper rod systems are commonly used in the metal casting industry. However, stopper rod bottom-pouring systems have not yet been developed for the lower thermal masses of alloys typically used in the investment casting industry. Large thermal masses used with bottom pour systems are typically limited for ladles larger than 700 kg and to certain alloys with higher fluidity and longer solidification time like cast iron, aluminum alloys etc. In this study, bottom pour ladle designs and low thermal mass refractory systems have been developed and evaluated in production investment foundry trials with 300 kg pouring ladle. The ladles system and pouring practices used will be described along with the results from the pouring trials for SS304 that represents typical alloys used in Investment casting industries. Optimization of the variables used in an experimentation using Genetic algorithm is also explained. 相似文献