全文获取类型
收费全文 | 5738篇 |
免费 | 312篇 |
国内免费 | 15篇 |
专业分类
电工技术 | 93篇 |
综合类 | 39篇 |
化学工业 | 1063篇 |
金属工艺 | 193篇 |
机械仪表 | 102篇 |
建筑科学 | 247篇 |
矿业工程 | 24篇 |
能源动力 | 155篇 |
轻工业 | 492篇 |
水利工程 | 53篇 |
石油天然气 | 8篇 |
无线电 | 416篇 |
一般工业技术 | 1117篇 |
冶金工业 | 1160篇 |
原子能技术 | 15篇 |
自动化技术 | 888篇 |
出版年
2023年 | 83篇 |
2022年 | 134篇 |
2021年 | 201篇 |
2020年 | 141篇 |
2019年 | 129篇 |
2018年 | 170篇 |
2017年 | 183篇 |
2016年 | 217篇 |
2015年 | 169篇 |
2014年 | 223篇 |
2013年 | 301篇 |
2012年 | 330篇 |
2011年 | 362篇 |
2010年 | 223篇 |
2009年 | 223篇 |
2008年 | 240篇 |
2007年 | 180篇 |
2006年 | 165篇 |
2005年 | 98篇 |
2004年 | 102篇 |
2003年 | 97篇 |
2002年 | 91篇 |
2001年 | 75篇 |
2000年 | 51篇 |
1999年 | 78篇 |
1998年 | 377篇 |
1997年 | 199篇 |
1996年 | 156篇 |
1995年 | 96篇 |
1994年 | 93篇 |
1993年 | 81篇 |
1992年 | 26篇 |
1991年 | 41篇 |
1990年 | 31篇 |
1989年 | 44篇 |
1987年 | 32篇 |
1986年 | 21篇 |
1985年 | 33篇 |
1984年 | 22篇 |
1983年 | 31篇 |
1982年 | 30篇 |
1981年 | 23篇 |
1980年 | 21篇 |
1979年 | 25篇 |
1978年 | 17篇 |
1977年 | 31篇 |
1976年 | 75篇 |
1975年 | 19篇 |
1919年 | 18篇 |
1910年 | 23篇 |
排序方式: 共有6065条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
B. Schönfelder G. Gottstein L. S. Shvindlerman 《Metallurgical and Materials Transactions A》2006,37(6):1757-1771
While the motion of twist boundaries can be readily studied by atomistic simulations with molecular dynamics (MD) under the
action of an elastic driving force, the approach fails for tilt boundaries. This is due to the interaction of the elastic
stress with the grain boundary (GB) structure, which causes plastic strain by GB sliding. A novel concept, the orientation
correlated driving force, is introduced to circumvent this problem. It is shown that this concept can be successfully applied
to the study of the migration of tilt boundaries. The migration behavior of several twist and tilt GBs was investigated. The
transition from low-to high-angle boundaries can be captured, and a structural transition of tilt boundaries was found at
high temperatures, which also affected the migration behavior. The results compare well with experimental results of the motion
high-angle boundaries, but for low-angle boundaries, the agreement is poor.
This article is based on a presentation made in the “Hillert Symposium on Thermodynamics & Kinetics of Migrating Interfaces
in Steels and Other Complex Alloys,” December 2–3, 2004, organized by The Royal Institute of Technology in Stockholm, Sweden. 相似文献
5.
6.
7.
Requirements engineering in health care: the example of chemotherapy planning in paediatric oncology
Health care is characterized by highly complex processes of patient care that require unusual amount of communication between different health care professionals of different institutions. Sub-optimal processes can significantly impact on the patient’s health, increase the consumption of services and resources and in severe cases can lead to the patient death. For these reasons, requirements engineering for the development of information technology in health care is a complex process as well: without constant and rigorous evaluation, the impact of new systems on the quality of care is unknown and it is possible that badly designed systems significantly harm patients. To overcome these limitations, we present and discuss an approach to requirements engineering that we applied for the development of applications for chemotherapy planning in paediatric oncology. Chemotherapy planning in paediatric oncology is complex and time-consuming and errors must be avoided by all means. In the multi-hospital/multi-trial-centre environment of paediatric oncology, it is especially difficult and time-consuming to analyse requirements. Our approach combines a grounded theory approach with evolutionary prototyping based on the constant development and refinement of a generic domain model, in this case a domain model for chemotherapy planning in paediatric oncology. The prototypes were introduced in medical centres and final results show that the developed generic domain model is adequate. 相似文献
8.
A modified natural surfactant was administered to a patient with life-threatening adult respiratory distress syndrome caused by viral pneumonia. Subsequently, there was a marked improvement in gas exchange. In order to assess the mechanism for improved oxygenation, computed tomography of the lungs was done. Quantitative analysis of the scans taken before and after surfactant administration indicates that improvement in gas exchange was largely due to the expansion of underinflated and collapsed lung areas. Although this is a single case report, it provides insight into the possible beneficial effect of instilled surfactant in severe respiratory distress from viral pneumonia. 相似文献
9.
In the oxidation of TiAl alloys, the role of scale-growth stresses formed during oxidation has, thus far, been unknown. In the present paper the oxide-growth stresses were investigated by the deflection-test method in monofacial oxidation (DTMO) accompanied by acoustic-emission measurements. On unmodified surfaces the growth stresses are compressive and reach levels of around –100 MPa. At the same time, significant acoustic emission occurs indicating that even under isothermal conditions, stresses are relieved by a scale-cracking mechanism. For oxide scales on TiAl surfaces, which had been ion implanted with chlorine before oxidation, a very thin protective alumina layer is formed which, however, develops growth stresses in the range of several GPa, accompanied by intensive acoustic emission. In all stress–time curves, a dynamic situation is observed. This consists of phases of stress relief by scale microcracking and phases of stresses increase due to crack healing and further oxide growth. As a result, the level of stress as a function of oxidation time, is characterized by an oscillating course. 相似文献
10.
Jürgen Schönbeçk 《NTM》2004,12(2):80-99
Thomas Fincke (January 6th, 1561–April 24th, 1656), born in Flensburg (Germany), was one of the very most important and significant scientists in Denmark during the
seventeenth century, a mathematician and astrologer and physician in the beginning of modern science, a representative of
humanism and an influentual academic organizer. He studied in Strasbourg (since 1577) and Padua (since 1583) and received
his M.D. in Basel (1587), he practised as a physician throughout his life (since 1587 or 1590) and became a professor at Copenhagen
(1591). But he was best known because of his Geometriae rotundi libri XIIII (1583), a famous book on plane and spherical trigonometry, based not on Euclid but on Petrus Ramus. In this influentual work,
in which Fincke introduced the terms tangent and secant and probable first noticed the Law of Tangents and the so-called Newton-Oppel-Mauduit-Simpson-Mollweide-Gauss-formula,
he showed himself to be „abreast of the mathematics of his time“.
相似文献