全文获取类型
收费全文 | 2261篇 |
免费 | 38篇 |
专业分类
电工技术 | 9篇 |
综合类 | 4篇 |
化学工业 | 147篇 |
金属工艺 | 19篇 |
机械仪表 | 14篇 |
建筑科学 | 43篇 |
矿业工程 | 2篇 |
能源动力 | 28篇 |
轻工业 | 126篇 |
水利工程 | 15篇 |
石油天然气 | 33篇 |
无线电 | 105篇 |
一般工业技术 | 177篇 |
冶金工业 | 1420篇 |
原子能技术 | 13篇 |
自动化技术 | 144篇 |
出版年
2022年 | 8篇 |
2019年 | 12篇 |
2018年 | 15篇 |
2017年 | 13篇 |
2016年 | 13篇 |
2015年 | 15篇 |
2014年 | 26篇 |
2013年 | 69篇 |
2012年 | 19篇 |
2011年 | 27篇 |
2010年 | 38篇 |
2009年 | 31篇 |
2008年 | 46篇 |
2007年 | 36篇 |
2006年 | 57篇 |
2005年 | 26篇 |
2004年 | 34篇 |
2003年 | 38篇 |
2002年 | 36篇 |
2001年 | 27篇 |
2000年 | 21篇 |
1999年 | 67篇 |
1998年 | 388篇 |
1997年 | 237篇 |
1996年 | 172篇 |
1995年 | 99篇 |
1994年 | 74篇 |
1993年 | 88篇 |
1992年 | 40篇 |
1991年 | 40篇 |
1990年 | 32篇 |
1989年 | 33篇 |
1988年 | 27篇 |
1987年 | 25篇 |
1986年 | 25篇 |
1985年 | 30篇 |
1984年 | 9篇 |
1983年 | 17篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 18篇 |
1979年 | 8篇 |
1978年 | 16篇 |
1977年 | 33篇 |
1976年 | 80篇 |
1975年 | 13篇 |
1974年 | 8篇 |
1973年 | 9篇 |
1972年 | 9篇 |
1969年 | 7篇 |
排序方式: 共有2299条查询结果,搜索用时 15 毫秒
1.
DC Reynolds CE Leak KK Bajaj CE Stutz RL Jones KR Evans PW Yu WM Theis 《Canadian Metallurgical Quarterly》1989,40(9):6210-6217
2.
The atomistic structure and energies of high-index interphase boundaries are explored using a combination of molecular statics
and dynamics simulations with embedded atom potentials. We investigate planar boundaries between the α2 and γ phases in the Ti−Al system. The class of boundaries considered has a high-index boundary orientation; the orientation
relationship between the α2 and γ phases also is high index, and a set of planes from each phase meet edge to edge at the boundary plane. For the particular
case of a boundary that is commensurate in one direction and coincides with a moiré plane given by the so-called “Δg” diffraction condition, the boundary is not structurally singular, but it is energetically stable and does not appear to
dissociate into other low-energy configurations. Misfit compensating defects are not observed; misfit in directions other
than the commensurate one appears to be distributed uniformly. The boundary energy is evaluated as a function of the orientation
of the boundary plane, and the edge-to-edge (moiré) boundary is found to lie in an energy cusp.
This article is based on a presentation made in the “Hume-Rothery Symposium on Structure and Diffusional Growth Mechanisms
of Irrational Interphase Boundaries,” which occurred during the TMS Winter meeting, March 15–17, 2004, in Charlotte, NC, under
the auspices of the TMS Alloy Phases Committee and the co-sponsorship of the TMS-ASM Phase Transformations Committee. 相似文献
3.
The goal of the PMS project is to produce an environment in which the intelligent online assessment of the design for large-scale ADA programming projects is provided. The focus is on the representation of knowledge about the design process for an individual module. Changes in pseudocode complexity are measured in terms of partial metrics. These metrics can take the designers inferences about the pseudocode program structure into account when assessing module complexity. Next, a model of the stepwise refinement process is given which demonstrates how pseudocode elaboration decisions can be modelled in partial metric terms. Finally, the decisions associated with each refinement step for 17 example refinements taken from the computer science literature are described using partial metrics. 相似文献
4.
M Fornerod J van Deursen S van Baal A Reynolds D Davis KG Murti J Fransen G Grosveld 《Canadian Metallurgical Quarterly》1997,16(4):807-816
The oncogenic nucleoporin CAN/Nup214 is essential in vertebrate cells. Its depletion results in defective nuclear protein import, inhibition of messenger RNA export and cell cycle arrest. We recently found that CAN associates with proteins of 88 and 112 kDa, which we have now cloned and characterized. The 88 kDa protein is a novel nuclear pore complex (NPC) component, which we have named Nup88. Depletion of CAN from the NPC results in concomitant loss of Nup88, indicating that the localization of Nup88 to the NPC is dependent on CAN binding. The 112 kDa protein is the human homologue of yeast CRM1, a protein known to be required for maintenance of correct chromosome structure. This human CRM1 (hCRM1) localized to the NPC as well as to the nucleoplasm. Nuclear overexpression of the FG-repeat region of CAN, containing its hCRM1-interaction domain, resulted in depletion of hCRM1 from the NPC. In CAN-/- mouse embryos lacking CAN, hCRM1 remained in the nuclear envelope, suggesting that this protein can also bind to other repeat-containing nucleoporins. Lastly, hCRM1 shares a domain of significant homology with importin-beta, a cytoplasmic transport factor that interacts with nucleoporin repeat regions. We propose that hCRM1 is a soluble nuclear transport factor that interacts with the NPC. 相似文献
5.
Ten groups of 14 immunosuppressed NMRI-mice (nu/nu) were raised and kept under germ-reduced conditions. The control animals were fed a germ-reduced diet, nine other groups received the same diet with selegiline (CAS 14611-51-9, Deprenyl) or lipoic acid (thioctic acid, CAS 62-46-4) admixed at various amounts. The 50% survival rate, the total life span of each group and the areas under the curves were determined to evaluate life expectancy as compared to the controls. The racemate of lipoic acid at high dosage (350 mg/kg body weight) reduced the life span significantly. The S(-)-enantiomer of lipoic acid (75 mg/kg body weight) increased the 50% survival rate, whereas the physiologic R(+)-enantiomer (9 mg/kg body weight) expanded the total life span of its group. Alteration of only one out of three parameters was not considered significant. All other groups except for one did not differ from controls: only animals which obtained 75 micrograms selegiline per kg of body weight and per day exerted increased life expectancies by all three parameters. This group exhibited also in statistical evaluation a significantly (p < 0.05) prolongated survival time up to about 200% as compared to the control animals. 相似文献
6.
DI Timokhin AV Istomin TS Shushkova TG Voronel' IG Mikha?lov 《Canadian Metallurgical Quarterly》1997,(2):19-21
Based on generalization and analysis of instructions and guidelines for therapeutical and prophylactic diets of workers, ways of its optimization were proposed, by using bifide-containing acid dairy products as a preventive agent against possible occupational diseases caused by occupational factors. 相似文献
7.
Cancer statistics, 1993 总被引:1,自引:0,他引:1
8.
9.
In target detection tasks, responses are faster when displays have 2 targets (redundant-targets effect; RTE) and slower when they have no targets (nontargets effect; NTE) relative to displays with a single target. The psychological refractory period paradigm was used to localize these effects. In Experiment 1, participants classified tones as high or low and then classified letters as targets or nontargets after a short or long stimulus onset asynchrony (SOA). The magnitudes of the RTE and NTE did not depend on SOA. In Experiment 2, the order of the tasks was reversed, and at short SOAs the RTE and NTE had similar magnitudes for both tone discrimination and target detection responses. These findings suggest that the RTE and NTE arise during response selection. Interactive effects of tone pitch with the number and type of target features were also observed, and these were tentatively interpreted as synesthetic effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.