全文获取类型
收费全文 | 350篇 |
免费 | 10篇 |
专业分类
电工技术 | 3篇 |
综合类 | 1篇 |
化学工业 | 76篇 |
金属工艺 | 8篇 |
机械仪表 | 6篇 |
建筑科学 | 1篇 |
能源动力 | 1篇 |
轻工业 | 10篇 |
水利工程 | 1篇 |
无线电 | 59篇 |
一般工业技术 | 75篇 |
冶金工业 | 92篇 |
原子能技术 | 3篇 |
自动化技术 | 24篇 |
出版年
2023年 | 3篇 |
2021年 | 3篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2015年 | 2篇 |
2014年 | 5篇 |
2013年 | 12篇 |
2012年 | 14篇 |
2011年 | 10篇 |
2010年 | 11篇 |
2009年 | 8篇 |
2008年 | 14篇 |
2007年 | 18篇 |
2006年 | 16篇 |
2005年 | 11篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 3篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 24篇 |
1997年 | 12篇 |
1996年 | 13篇 |
1995年 | 7篇 |
1994年 | 11篇 |
1993年 | 11篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 6篇 |
1988年 | 8篇 |
1987年 | 3篇 |
1986年 | 7篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1968年 | 1篇 |
1967年 | 2篇 |
1966年 | 2篇 |
1965年 | 2篇 |
1964年 | 1篇 |
排序方式: 共有360条查询结果,搜索用时 15 毫秒
1.
Examining a curvilinear relationship between communication frequency and team performance in cross-functional project teams 总被引:3,自引:0,他引:3
Patrashkova-Volzdoska R.R. McComb S.A. Green S.G. Compton W.D. 《Engineering Management, IEEE Transactions on》2003,50(3):262-269
The performance of a cross-functional team depends on the skillful and innovative combination of information and expertise from all team members. Communication is the medium through which team members share the information required for successful amalgamation. In this work, we postulate that both high and low levels of team communication can impede team performance, thus leading to a curvilinear relationship between team performance and team communication. To test this hypothesis, the relationships between face-to-face, e-mail, and telephone communication and team performance were examined for 60 cross-functional project teams. E-mail and face-to-face communication were curvilinearly associated with performance, but telephone communication was not. Further analysis of the communication frequency between colocations showed that e-mail is the only medium for which usage increased with distance. 相似文献
2.
The design, fabrication and characterisation of GaAs Schottky-barrier photodiodes with evaporated, free-standing-metal airbridges is reported. The photodiodes were fabricated using all dry-etching techniques. Anisotropic chemically assisted ion beam etching was used to etch vertical sidewall mesas, and isotropic reactive ion etching was used to etch a lateral tunnel. A free-standing-metal airbridge created by the lateral tunnel etch results in isolation of the active area at the same time providing free-standing-metal interconnection to the contact pad.<> 相似文献
3.
The optical properties of gold nanoparticles have been known for a number of years and recent advances in laser power have now allowed the non-linear optical properties to be studied. In this short review paper, the various theories that have been used to describe the optical properties of gold nanoparticles are presented. Methods of preparing gold nanoparticles in glasses are explained briefly, as well as characterization techniques. The optical properties of gold nanoparticles are reviewed, as well as the effects of particle size, shape, concentration and c. 相似文献
4.
The theory of EC reactions at a wall-jet electrode is developed using a computational procedure based on the Backwards Implicit Method. In particular, for the case of a reversible electron transfer, it is shown that the variation of the halfwave potential with solution flow rate provides a means of characterizing the EC mechanism. A working curve is presented which permits the analysis of experimental data and the deduction of the rate constant for the following chemical reaction.Nomenclature
a
diameter of the jet
- a
j
matrix element (j = 2,3,...,
)
- b
j
matrix element (j = 1,2,...,
)
-
C
j
matrix element (j = 1,2,...,
)
-
D
diffusion coefficient
-
d
j
vector element (j = 1,2,...,
)
-
E
electrode potential
-
E
0
standard electrode potential of A/B couple
-
F
Faraday constant
-
g(A)
normalized concentration of A
-
g(B)
normalized concentration of B
-
I
current
-
I
LIM
transport limited curren
-
J
number of points inr-direction on finite difference grid
-
j
conter,j=1, 2,...,J
-
K
Number of points inz-direction on finite difference grid
-
K
j,k+1
normalized rate constant (Equation 23)
-
k
counter,k=1, 2,...,K
-
k
counter,k=1, 2,...,K
-
k
c
experimental constant
-
first order rate constant
-
M
constant defined byM =k
c
4
V
f
3
/23a2
-
R
electrode radius
-
r
radial coordinate
-
u
j
vector element (j = 1,2,...,
)
-
V
volume flow rate (cm3 s–1)
- r
solution velocity inr-direction
- z
solution velocity inz-direction
-
z
coordinate normal to electrode surface
-
dimensionless distance parameter (see Equation 5)
-
dimensionless variable (Equation 25)
-
normalized electrode potential
- 1/2
normalized halfwave potential
-
kinematic viscosity (cm2 s–1)
-
dimensionless variable (Equation 26)
- {d}
k
vector{d
1,k
,d
2,k
,...d
j–1,k}
- {u}
k
vector {u
1,k+1,u
2,k+1,...,u
j–1,k+1} 相似文献
5.
6.
Responses of fig wasps to host plant volatile cues 总被引:4,自引:0,他引:4
Fig wasps (Chalcidoidea; Agaonidae) are intimately associated with the 750 or so species of fig trees (Ficus, Moraceae). Each tree species is usually pollinated by a single species of wasp belonging to the subfamily Agaoninae, while other wasps of the family are parasitoids or seed predators. Previous experiments have shown that the wasps are attracted to the trees by volatiles emanating from the figs. Using fig-bearing trees and arrays of sticky traps baited with figs, we investigated the specificity of wasp attraction and its timing. The pollinators of two closely relatedFicus species were specifically attracted to figs of their host species and only at the time when figs were ready to be pollinated. Some nonpollinating fig wasps appear to respond to the same volatile cues. 相似文献
7.
Ian Streeter Gregory G. Lidong Richard G. Compton 《Sensors and actuators. B, Chemical》2008,133(2):462-466
Cyclic voltammetry is recorded of the oxidation of ferrocyanide on a glassy carbon electrode modified with multiple layers of single-walled carbon nanotubes. The current response is interpreted in terms of semi-infinite planar diffusion towards the macro-electrode surface and in terms of oxidation of the electroactive species trapped in pockets in between the nanotubes. A thin layer model is used to illustrate the effects of diffusion within a porous layer. It is found that a semi-infinite planar diffusion model alone is not appropriate for interpreting the kinetics of the electron transfer at this electrode surface. In particular, caution should be exercised in respect of comparing voltammetric peak-to-peak potential separations between naked electrodes and nanotube-modified electrodes for the inference of electrocatalysis via electron transfer via the nanotubes. 相似文献
8.
Electrochemical Behavior of Single CuO Nanoparticles: Implications for the Assessment of their Environmental Fate 下载免费PDF全文
Giorgia Zampardi Jorg Thöming Hendrik Naatz Hatem M. A. Amin Suman Pokhrel Lutz Mädler Richard G. Compton 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(32)
The electrochemical behavior of copper oxide nanoparticles is investigated at both the single particle and at the ensemble level in neutral aqueous solutions through the electrode‐particle collision method and cyclic voltammetry, respectively. The influence of Cl? and NO3? anions on the electrochemical processes occurring at the nanoparticles is further evaluated. The electroactivity of CuO nanoparticles is found to differ between the two types of experiments. At the single‐particle scale, the reduction of the CuO nanoparticles proceeds to a higher extent in the presence of chloride ion than of nitrate ion containing solutions. However, at the multiparticle scale the CuO reduction proceeds to the same extent regardless of the type of anions present in solution. The implications for assessing realistically the environmental fate and therefore the toxicity of metal‐based nanoparticles in general, and copper‐based nanoparticles in particular, are discussed. 相似文献
9.
10.
The reduction of pyrene (Py) at a mercury channel electrode is studied in acetonitrile solution, both in the dark and under conditions where the pyrene radical anion (Py−.) is photoexcited, using a wavelength of 501.7 nm. In the dark a reversible one-electron process occurs forming the radical anion. However, upon photoexcitation of the electrogenerated radical anion, photocurrents are observed, and the precise electrode mechanism is shown to be:
The photocurrent arising from further reduction of Py, since rapid homogeneous reactions of Py−2 give electroinactive products. With this scheme an “effective” second order decay of Py−√ is observed, RATE = −keff[Py−√]p2 where keff is proportional to k3 I/kf. keff has been evaluated from analysis of the limiting current-flow rate behaviour at the channel electrode at the channel electrode. This was found to be 4.0 ± 0.1 × 103 mol−1 dm3 s−1 at a light intensity of 0.30 W cm−2 and a pyrene concentyration of 2.97 mM. 相似文献