全文获取类型
收费全文 | 1084篇 |
免费 | 38篇 |
专业分类
电工技术 | 9篇 |
综合类 | 1篇 |
化学工业 | 192篇 |
金属工艺 | 26篇 |
机械仪表 | 45篇 |
建筑科学 | 48篇 |
矿业工程 | 3篇 |
能源动力 | 18篇 |
轻工业 | 141篇 |
水利工程 | 8篇 |
石油天然气 | 3篇 |
无线电 | 55篇 |
一般工业技术 | 156篇 |
冶金工业 | 296篇 |
原子能技术 | 8篇 |
自动化技术 | 113篇 |
出版年
2023年 | 6篇 |
2022年 | 20篇 |
2021年 | 19篇 |
2020年 | 18篇 |
2019年 | 14篇 |
2018年 | 15篇 |
2017年 | 20篇 |
2016年 | 31篇 |
2015年 | 26篇 |
2014年 | 27篇 |
2013年 | 54篇 |
2012年 | 36篇 |
2011年 | 51篇 |
2010年 | 50篇 |
2009年 | 33篇 |
2008年 | 42篇 |
2007年 | 44篇 |
2006年 | 30篇 |
2005年 | 23篇 |
2004年 | 21篇 |
2003年 | 17篇 |
2002年 | 28篇 |
2001年 | 12篇 |
2000年 | 17篇 |
1999年 | 32篇 |
1998年 | 82篇 |
1997年 | 41篇 |
1996年 | 33篇 |
1995年 | 25篇 |
1994年 | 24篇 |
1993年 | 27篇 |
1992年 | 15篇 |
1991年 | 15篇 |
1990年 | 8篇 |
1989年 | 12篇 |
1987年 | 7篇 |
1986年 | 13篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1982年 | 9篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 10篇 |
1978年 | 11篇 |
1977年 | 12篇 |
1976年 | 16篇 |
1975年 | 8篇 |
1974年 | 5篇 |
1966年 | 5篇 |
1965年 | 4篇 |
排序方式: 共有1122条查询结果,搜索用时 15 毫秒
11.
Mobile learning is increasing in popularity, but not all university students have mobile devices to support it. Our study investigated cross-platform software that has the potential to allow education practitioners to provide mobile support to their students’ learning, while offering similar functionality to non-mobile users via more traditional computing platforms. Undergraduate students were trained in the use of multi-platform cloud-based note-taking software (Evernote), and used the software in independent study for 8 weeks. Data show adoption for a range of functions, particularly gathering and managing information, organisation and planning, and the recording of ideas. Multimedia functions were also adopted innovatively by some students. Use for reflection was rare. Non-adopters were in a minority, giving low utility appraisals and difficulty in changing habits as reasons. Subjective evaluations and recommendations showed that a majority of students felt positive about the software and found it quick and easy to use. Mobile and non-mobile users only differed on the number of locations in which they used the software, and the proportion of notes classified as ideas, both being higher in mobile users. The data provide decision support for education practitioners who wish to provide mobile learning to their students alongside traditional platforms. 相似文献
12.
13.
Eric N. Hanson I.-Cheng Chen Roxana Dastur Kurt Engel Vijay Ramaswamy Wendy Tan Chun Xu 《The VLDB Journal The International Journal on Very Large Data Bases》1998,7(1):12-24
A software architecture is presented that allows client application programs to interact with a DBMS server in a flexible
and powerful way, using either direct, volatile messages, or messages sent via recoverable queues. Normal requests from clients
to the server and replies from the server to clients can be transmitted using direct or recoverable messages. In addition,
an application event notification mechanism is provided, whereby client applications running anywhere on the network can register
for events, and when those events are raised, the clients are notified. A novel parameter passing mechanism allows a set of
tuples to be included in an event notification. The event mechanism is particularly useful in an active DBMS, where events
can be raised by triggers to signal running application programs.
Received July 21, 1995 / Accepted May 30, 1996 相似文献
14.
Controlling Spin Qubits in Quantum Dots 总被引:1,自引:0,他引:1
Hans-Andreas Engel L. P. Kouwenhoven Daniel Loss C. M. Marcus 《Quantum Information Processing》2004,3(1-5):115-132
We review progress on the spintronics proposal for quantum computing where the quantum bits (qubits) are implemented with electron spins. We calculate the exchange interaction of coupled quantum dots and present experiments, where the exchange coupling is measured via transport. Then, experiments on single spins on dots are described, where long spin relaxation times, on the order of a millisecond, are observed. We consider spin-orbit interaction as sources of spin decoherence and find theoretically that also long decoherence times are expected. Further, we describe the concept of spin filtering using quantum dots and show data of successful experiments. We also show an implementation of a read out scheme for spin qubits and define how qubits can be measured with high precision. Then, we propose new experiments, where the spin decoherence time and the Rabi oscillations of single electrons can be measured via charge transport through quantum dots. Finally, all these achievements have promising applications both in conventional and quantum information processing.
PACS: 03.67.Lx, 03.67.Mn, 73.23.Hk, 85.35.Be 相似文献
15.
Molten salt reactors (MSR) have many non-proliferation attributes. They can operate on the thorium-uranium fuel cycle which protects the fissile material by the daughter products of the inseparable U-232. MSRs can completely fission all plutonium and HEU, and as desired, ‘convert’ them to U-233. This also results in high, and efficient resource utilization, while diminishing the plutonium stock. On line processing, when applied, could free the waste from all fissile material. The fuel in the reactor stays protected by the intense radiation of the fission products. Fuel can also be protected in the reactor as well as outside the reactor by denaturing with natural uranium. A wide variety of MSRs are available, from ‘once through’ minimum processing reactors to ones with fuel processing which can breed fuel for converters. MSRs are extremely safe and simple reactors with good economic potential. 相似文献
16.
17.
Paola C. Bello-Medina Karina Corona-Cervantes Norma Gabriela Zavala Torres Antonio Gonzlez Marcel Prez-Morales Diego A. Gonzlez-Franco Astrid Gmez Jaime García-Mena Sofía Díaz-Cintra Gustavo Pacheco-Lpez 《International journal of molecular sciences》2022,23(15)
Alzheimer’s disease (AD) is a multifactorial pathology characterized by β-amyloid (Aβ) deposits, Tau hyperphosphorylation, neuroinflammatory response, and cognitive deficit. Changes in the bacterial gut microbiota (BGM) have been reported as a possible etiological factor of AD. We assessed in offspring (F1) 3xTg, the effect of BGM dysbiosisdysbiosis in mothers (F0) at gestation and F1 from lactation up to the age of 5 months on Aβ and Tau levels in the hippocampus, as well as on spatial memory at the early symptomatic stage of AD. We found that BGM dysbiosisdysbiosis with antibiotics (Abx) treatment in F0 was vertically transferred to their F1 3xTg mice, as observed on postnatal day (PD) 30 and 150. On PD150, we observed a delay in spatial memory impairment and Aβ deposits, but not in Tau and pTau protein in the hippocampus at the early symptomatic stage of AD. These effects are correlated with relative abundance of bacteria and alpha diversity, and are specific to bacterial consortia. Our results suggest that this specific BGM could reduce neuroinflammatory responses related to cerebral amyloidosis and cognitive deficit and activate metabolic pathways associated with the biosynthesis of triggering or protective molecules for AD. 相似文献
18.
项目名称:德国弗莱堡医疗诊所北区扩建工程-弗莱堡大学诊所急救中心业主:RegionofBaden-Wü rttem berg represented by University Construction Office建设地点:德国弗莱堡设计单位:KSP尤尔根·恩格尔事务所建筑面积:2.04万m2病床数量:56床建筑层数:3层地上,2层地下 相似文献
19.
20.