全文获取类型
收费全文 | 1616篇 |
免费 | 91篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 27篇 |
综合类 | 1篇 |
化学工业 | 616篇 |
金属工艺 | 23篇 |
机械仪表 | 24篇 |
建筑科学 | 45篇 |
矿业工程 | 8篇 |
能源动力 | 68篇 |
轻工业 | 179篇 |
水利工程 | 6篇 |
石油天然气 | 6篇 |
无线电 | 102篇 |
一般工业技术 | 252篇 |
冶金工业 | 67篇 |
原子能技术 | 3篇 |
自动化技术 | 281篇 |
出版年
2024年 | 5篇 |
2023年 | 14篇 |
2022年 | 116篇 |
2021年 | 167篇 |
2020年 | 58篇 |
2019年 | 59篇 |
2018年 | 74篇 |
2017年 | 64篇 |
2016年 | 93篇 |
2015年 | 54篇 |
2014年 | 105篇 |
2013年 | 119篇 |
2012年 | 73篇 |
2011年 | 82篇 |
2010年 | 62篇 |
2009年 | 66篇 |
2008年 | 73篇 |
2007年 | 60篇 |
2006年 | 43篇 |
2005年 | 37篇 |
2004年 | 44篇 |
2003年 | 30篇 |
2002年 | 27篇 |
2001年 | 17篇 |
2000年 | 15篇 |
1999年 | 13篇 |
1998年 | 9篇 |
1997年 | 13篇 |
1996年 | 7篇 |
1995年 | 12篇 |
1994年 | 6篇 |
1993年 | 7篇 |
1992年 | 6篇 |
1991年 | 10篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有1708条查询结果,搜索用时 15 毫秒
11.
New Hormaphididae(Hemiptera,Aphidomorpha)from the Baltic Amber and its Palaeogeographic Significance
The present study describes a new genus and species Unicohormaphis sorini, which belongs to the subfamily Cerataphidinae. The contemporary distribution of aphids belonging to the Hormaphididae family is summarized and analyzed. According to the obtained data, the climate warming in Eocene was conducive to the expansion of the family over the areas of Europe. Subsequent climate changes, resulting from epeirogenic and orogenic movements towards the end of Eocene, led to a considerable cooling and drying of climate in the northern hemisphere. These processes contributed to the shrinking down of areas covered by subtropical forests, which constituted the habitat of Hormaphididae (Cerataphidinae). Retaining their way of life, the Cerataphidinae were forced to limit their distribution, and the representatives of the family in Europe became completely extinct. 相似文献
12.
Lopes da Silva FH Blanes W Kalitzin SN Parra J Suffczynski P Velis DN 《IEEE transactions on bio-medical engineering》2003,50(5):540-548
In this overview, we consider epilepsies as dynamical diseases of brain systems since they are manifestations of the property of neuronal networks to display multistable dynamics. To illustrate this concept we may assume that at least two states of the epileptic brain are possible: the interictal state characterized by a normal, apparently random, steady-state electroencephalography (EEG) ongoing activity, and the ictal state, that is characterized by paroxysmal occurrence of synchronous oscillations and is generally called, in neurology, a seizure. The transition between these two states can either occur: 1) as a continuous sequence of phases, like in some cases of mesial temporal lobe epilepsy (MTLE); or 2) as a sudden leap, like in most cases of absence seizures. In the mathematical terminology of nonlinear systems, we can say that in the first case the system's attractor gradually deforms from an interictal to an ictal attractor. The causes for such a deformation can be either endogenous or external. In this type of ictal transition, the seizure possibly may be anticipated in its early, preclinical phases. In the second case, where a sharp critical transition takes place, we can assume that the system has at least two simultaneous interictal and ictal attractors all the time. To which attractor the trajectories converge, depends on the initial conditions and the system's parameters. An essential question in this scenario is how the transition between the normal ongoing and the seizure activity takes place. Such a transition can occur either due to the influence of external or endogenous factors or due to a random perturbation and, thus, it will be unpredictable. These dynamical changes may not be detectable from the analysis of the ongoing EEG, but they may be observable only by measuring the system's response to externally administered stimuli. In the special cases of reflex epilepsy, the leap between the normal ongoing attractor and the ictal attractor is caused by a well-defined external perturbation. Examples from these different scenarios are presented and discussed. 相似文献
13.
爱立信IMS weShare业务有20%的开发与用户视觉体验相关(用户界面、图标、标签以及进度条),其它的80%则主要致力于设备间的系统.与此相对比,用户的体验则完全(100%)有赖于其可接触的事物. 相似文献
14.
15.
In recent years there has been a fast grow of various electronic services.Each service requires specif-ic credentials for authenticating and authorizing user ac-cess or specific subset of user's personal information for transactions the service offers.Such a situation causes problems with remembering multiple,service-specific authentication data,with controlling user's personal data spread across different services-problems with managing user's identities.This paper is an overview on Identity Management(IdM... 相似文献
16.
Piotr Choida 《Communications Letters, IEEE》2007,11(2):200-200
For original paper by D.A. Schupke see ibid., vol.9, no 4, p.360-2, April 2005. It is shown that in the above letter by Schupke corollaries related to a necessary condition on the network to ensure that a set of Hamiltonian p-cycles is able to reach the theoretical logical redundancy bound are wrongly calculated 相似文献
17.
Micha? Zaborowski Daniel Tomaszewski Piotr Dumania Piotr Grabiec 《Microelectronics Reliability》2011,51(7):1162-1165
Development of Si nanowire-based FETs, suitable for sensor applications is reported. Process sequences for SOI and bulk p-channel FinFETs are described. SEM observations of the fabricated devices (180 nm wide, 87 nm or 175 nm high) are presented and discussed. Electrical characteristics measurements and basic characterisation results obtained for these devices are described. A procedure for serial resistance extraction has been mentioned in more detail, due to its high value inherent in the process used. Several aspects of the device sensitivity to front- and back-gate control have been discussed from the point of view of its application in biochemical detectors. 相似文献
18.
Hillock growth kinetics and size distribution were investigated in Al, Al:Si 1% and Al:Si1%:Cu 0.5% layers. Metallization surface was examined by optical, SEM and TEM microscopy, stylus profiling and an automatic method of hillock recognition from a microscope image. The method allowed for counting hillocks in a desired range of their diameter d. Surface density of hillocks was measured as a function of time of furnace annealing at 400°C and as a function of temperature of RTP annealing. A maximum hillock size was found to increase linearly with metallization layer thickness and with logarithm of annealing time. A total area occupied by hillocks was evaluated. Hillock density decreased versus 1/T with an activation energy of 0.28 eV for Al and 0.31 eV for Al:Si. It was found, that a normalized hillock density N may be expressed by a formula N=N0 exp(−cd). Values for N0 and c are given together with a short discussion. 相似文献
19.
Achim Streit Piotr Bala Alexander Beck-Ratzka Krzysztof Benedyczak Sandra Bergmann Rebecca Breu Jason Milad Daivandy Bastian Demuth Anastasia Eifer André Giesler Björn Hagemeier Sonja Holl Valentina Huber Nadine Lamla Daniel Mallmann Ahmed Shiraz Memon Mohammad Shahbaz Memon Michael Rambadt Morris Riedel Mathilde Romberg Bernd Schuller Tobias Schlauch Andreas Schreiber Thomas Soddemann Wolfgang Ziegler 《电信纪事》2010,65(11-12):757-762
UNICORE is a European Grid Technology with more than 10 years of history. Originating from the Supercomputing domain, the latest version UNICORE 6 has turned into a general-purpose Grid technology that follows established standards and offers a rich set of features to its users. The paper starts with an architectural insight into UNICORE 6, highlighting the workflow features, standards and the different clients. Next, the current state of advancement is presented by describing recent developments. The paper closes with an outlook on future planned developments. 相似文献
20.
Energy Harvesting: Electric Field Assisted Microfluidic Platform for Generation of Tailorable Porous Microbeads as Cell Carriers for Tissue Engineering (Adv. Funct. Mater. 20/2018) 下载免费PDF全文