全文获取类型
收费全文 | 1639篇 |
免费 | 183篇 |
国内免费 | 126篇 |
专业分类
电工技术 | 189篇 |
综合类 | 66篇 |
化学工业 | 151篇 |
金属工艺 | 29篇 |
机械仪表 | 124篇 |
建筑科学 | 163篇 |
矿业工程 | 33篇 |
能源动力 | 98篇 |
轻工业 | 101篇 |
水利工程 | 27篇 |
石油天然气 | 62篇 |
武器工业 | 6篇 |
无线电 | 162篇 |
一般工业技术 | 82篇 |
冶金工业 | 31篇 |
原子能技术 | 15篇 |
自动化技术 | 609篇 |
出版年
2024年 | 3篇 |
2023年 | 18篇 |
2022年 | 45篇 |
2021年 | 48篇 |
2020年 | 40篇 |
2019年 | 38篇 |
2018年 | 21篇 |
2017年 | 34篇 |
2016年 | 39篇 |
2015年 | 63篇 |
2014年 | 95篇 |
2013年 | 108篇 |
2012年 | 131篇 |
2011年 | 165篇 |
2010年 | 128篇 |
2009年 | 115篇 |
2008年 | 99篇 |
2007年 | 101篇 |
2006年 | 94篇 |
2005年 | 89篇 |
2004年 | 71篇 |
2003年 | 76篇 |
2002年 | 63篇 |
2001年 | 43篇 |
2000年 | 36篇 |
1999年 | 40篇 |
1998年 | 38篇 |
1997年 | 25篇 |
1996年 | 16篇 |
1995年 | 18篇 |
1994年 | 7篇 |
1993年 | 10篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1973年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有1948条查询结果,搜索用时 17 毫秒
1.
Musculoskeletal injuries are well-known disorders among the agricultural tractor operators. Overexertion is a critical factor which can agitate these injuries. Physical body characteristics should be measured for an ergonomically best-fit-optimal design for the operators. In this study, a designed setup was employed to derive the applied forces by tractor operators on the control tools. The different muscle strengths including leg/foot strength, hand push/pull strength, and torque strength applied by both hands were measured. A comparison was made for the obtained values for different strengths by considering the effects of hand dominance. The obtained data were used to estimate the maximum allowed forces in these tools. In contrast to the previous studies, the minimum allowed actuating forces of the pedals were calculated using reasonable assumptions. These values could provide more comfort and less exhaustion for the tractor operators. The obtained ranges were benchmarked against corresponding recommended values in some standards (ISO, ISIRI, and ASABE family). The results revealed the unsuitability of evaluated standards for a proper design and the excessive overestimation of those recommended values (in some cases more than 3 times). In all of the design procedure, a suitable attention was paid to accommodate it with more than 90% of target population.Relevance to industryA prosperous industry which considers ergonomic factors in the design of agricultural machine workplace can overcome the disorders and generate more comfort. Evaluating more exact mechanical forces can result in a suitable design of workplace. 相似文献
2.
针对国外变频器价格昂贵、调试周期和维修周期长等特点,我公司自主研发了可替代进口机的高性能钻机国产专用变频器。该变频器能够从零开始调速。当钻井卡钻时,能及时断开电动机,在低速提升时,能最大限度地发挥电动机的动力特性,提供220%的转矩输出。变频器具有易安装、调试、维护,性能稳定。应用中据实测数据显示,采用变频改造后,打1口井可节省柴油15t。 相似文献
3.
托盘能否有效运用对物流的畅通与否关系重大,这已经引起了国内外专家和学者们的重视,并就此制定了托盘电子信息化管理系统,旨在更合理地使用托盘,推进托盘一体化和共用系统的建立。而RFID技术在托盘的电子信息化管理的应用更将大大提高物流的效率与准确性,托盘电子信息化管理将成为今后托盘管理的趋势。 相似文献
4.
5.
Carolyn McGregor Bruce Kneale Mark Tracy 《Journal of Network and Computer Applications》2007,30(4):1309-1323
Premature and ill term babies born in regional Australia must be moved to another hospital with Neonatal Intensive Care Unit (NICU) facilities. Transferred pre-term and critically ill term babies have higher mortality rates and much higher rates of long term disability than similar babies born in hospitals with NICU facilities. This paper details the Bush Babies Broadband project that aims to significantly improve the quality of treatment for babies born in rural, remote as well as urban areas by providing the first on-demand virtual NICU architecture in Australia. Real-time data collected from medical monitors and ventilators attached to the baby, audiovisual streams and static physiological data such as X-ray images are transmitted to the consulting Neonatologist to gain a better picture of the patient's condition than is currently available. The key contribution of this significant research is the infrastructure providing a mechanism for Neonatologists to receive information directly from a regional hospital, thereby preventing, in some cases, the immediate need to move the baby. A key benefit of this framework is that it is available to link regional hospitals with the supporting NICU Neonatologist ‘on demand’ eliminating the need to establish permanent point to point connections. This paper further describes the application of that architecture to a specific pilot connecting the Bathurst regional hospital with Neonatologists within the NICU at Nepean Hospital, Penrith Australia. 相似文献
6.
Frederick Bloom 《Chemical engineering science》2003,58(2):353-365
A model for a semi-batch flotation separation process has been developed, based on available microprocess probabilities, and compared to experimental data obtained using a WEMCO laboratory flotation cell. In general, the model predicts the correct experimental trends. In many cases, the model also predicts removal efficiency very well. Parametric studies reveal that the model predictions are sensitive to a stability parameter, the turbulent energy density in the flotation cell, the contact angle between the solid particle and fluid, and the ratio of initial-to-critical film thickness. 相似文献
7.
8.
深大露天矿的间断向半连续开采工艺过渡时,合理深度及半连续开采工艺的移设步距是两个重要的开采参数,对矿山的经济效果影响巨大,本文首次提出采用组合台阶单位体的开采来分析确定这两个重要的参数,得到的结论在霍林河煤矿的应用中取得了满意的结果,对其它类似矿山具有应用价值。 相似文献
9.
Lorenzo Bardella 《International Journal of Engineering Science》2003,41(7):741-768
We discuss the consequences of a different application of the principle the Modified Secant Method is [C. R. Acad. Sci. Paris Sér. IIb 320 (1995) 563] based on. In fact, we directly compute the second-order averages of the local fields available from the linear elastic homogenization procedure exploited in order to evaluate the effective elastic moduli. This method, which can be seen either as a simplification of the Modified Secant Method or as an extension of the Secant Method [J. Mech. Phys. Solids 26 (1979) 325], may be useful for any composite whose overall elastic constants need to be estimated by modeling the microstructure through Morphologically Representative Patterns [J. Mech. Phys. Solids 44 (1996) 307], which is for instance the case of syntactic foams [Int. J. Solids and Structures 38/40-41 (2001) 7235]. In order to show the accuracy of the proposed method, we apply it to several examples and compare its results with those obtainable by means of other analytical methods available in the literature, with numerical results of Finite Element simulations, and with experimental results. Closed-form solutions are derived for the effective yield stress of porous metals and incompressible composites reinforced with rigid spheres. 相似文献
10.
单元测试是软件测试过程的第一站,高质量的单元测试是软件质量保证的必要条件,本文就单元测试的概念、测试类型及规程作了简单的阐述,同时就单元测试进行了案例分析。 相似文献