全文获取类型
收费全文 | 23463篇 |
免费 | 1517篇 |
国内免费 | 58篇 |
专业分类
电工技术 | 324篇 |
综合类 | 30篇 |
化学工业 | 5441篇 |
金属工艺 | 923篇 |
机械仪表 | 1408篇 |
建筑科学 | 447篇 |
矿业工程 | 6篇 |
能源动力 | 940篇 |
轻工业 | 2080篇 |
水利工程 | 94篇 |
石油天然气 | 16篇 |
无线电 | 3964篇 |
一般工业技术 | 4966篇 |
冶金工业 | 1587篇 |
原子能技术 | 311篇 |
自动化技术 | 2501篇 |
出版年
2024年 | 22篇 |
2023年 | 295篇 |
2022年 | 427篇 |
2021年 | 739篇 |
2020年 | 524篇 |
2019年 | 534篇 |
2018年 | 753篇 |
2017年 | 733篇 |
2016年 | 850篇 |
2015年 | 675篇 |
2014年 | 1044篇 |
2013年 | 1516篇 |
2012年 | 1590篇 |
2011年 | 1936篇 |
2010年 | 1395篇 |
2009年 | 1425篇 |
2008年 | 1305篇 |
2007年 | 1009篇 |
2006年 | 879篇 |
2005年 | 766篇 |
2004年 | 701篇 |
2003年 | 647篇 |
2002年 | 651篇 |
2001年 | 554篇 |
2000年 | 480篇 |
1999年 | 454篇 |
1998年 | 734篇 |
1997年 | 438篇 |
1996年 | 413篇 |
1995年 | 269篇 |
1994年 | 177篇 |
1993年 | 156篇 |
1992年 | 117篇 |
1991年 | 104篇 |
1990年 | 83篇 |
1989年 | 94篇 |
1988年 | 82篇 |
1987年 | 70篇 |
1986年 | 55篇 |
1985年 | 47篇 |
1984年 | 38篇 |
1983年 | 30篇 |
1982年 | 31篇 |
1981年 | 27篇 |
1980年 | 32篇 |
1979年 | 13篇 |
1977年 | 23篇 |
1976年 | 33篇 |
1975年 | 18篇 |
1974年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 22 毫秒
91.
Jae-Hee Han Su Hong Lee A.S. Berdinsky Yong Weon Kim Ji-Beom Yoo Chong-Yun Park Jin Ju Choi Taewon Jung In Taek Han Jong Min Kim 《Diamond and Related Materials》2005,14(11-12):1891
In this report, the FE characteristics of carbon nanotubes (CNTs) treated using both thermal annealing and mechanical coatings on the as-grown CNTs systematically studied. It was found that in the high temperature annealed samples, CNTs were attacked at its root during annealing due to a small amount of oxygen, and were pulled out of the substrate in places after FE measurements because of the contact resistance. However, for the mechanically coated samples both with spin on glass (SOG) and polymethyl methacrylate (PMMA), CNTs were found to be nearly intact after FE measurements and showed reliable FE characteristics over repeatable voltage scan. The reliability of CNTs during FE could be owing to the strong adhesion of CNTs to the substrate both by SOG and PMMA coatings. 相似文献
92.
It has been well recognized that a diagnosis procedure that allows operators to successfully identify the nature of an on-going event is inevitable for an effective and appropriate recovery. Unfortunately, studies for a framework that can suggest a unified and consistent process in constructing a serviceable diagnosis procedure seem to be scant. Thus, Park et al. have suggested a systematic framework that can be used to construct a useful diagnosis procedure. In addition, the diagnosis procedure that is currently in use at the reference nuclear power plant (NPP) is reformed in order to demonstrate the appropriateness of the suggested framework. However, the necessity of a well-designed experiment is proposed to confirm the appropriateness of the suggested framework.In this regard, in this study, an experiment is conducted using a full-scope simulator of the reference NPP. From the experiment, two sets of operators' diagnosis performance data are collected, and then they are compared to investigate the change of an operator's diagnosis performance with respect to two types of diagnosis procedures.As a result, it is shown that an operator's diagnosis performance is improved when the revised diagnosis procedure is used. Therefore, it is reasonable to conclude that the suggested framework is useful in constructing an effective diagnosis procedure. 相似文献
93.
Jin-Woo Park Jae Yeong Park Yeun-Ho Joung Allen M.G. 《Components and Packaging Technologies, IEEE Transactions on》2002,25(1):106-111
A new process for the fabrication of high current and very low profile micromachined inductors has been developed. This process involves the combination of mechanical lamination and electrodeposition of copper windings by means of LIGA-like lithography through thick epoxy photoresists. The dimension of the fabricated inductor is 16 mm×19 mm×1 mm. The fabricated inductor has an inductance value of 1.2 μH with DC saturation current of 3 A and an electrical resistance of less than 30 mΩ at 10 kHz 相似文献
94.
Young-Taek Lee Jong-Sik Lim Jun-Seok Park Ahn D. Sangwook Nam 《Microwave and Wireless Components Letters, IEEE》2002,12(2):39-41
A new technique to reduce the phase noise in microwave oscillators is developed using the resonant characteristic of the defected ground structure (DGS). Two kinds of oscillators have been designed and measured for the examination of the reduction of phase noise by the DGS. The first adopts the DGS section under the microstrip line at the gate circuit, while the second has only the conventional microstrip line. Measurement shows reduced phase noise by 10-15 dB in the oscillator with the DGS compared to the conventional one 相似文献
95.
Public participation is essential in each step of the nuclear-related decision-making process. Recently, the electronic systems using the Internet have become quite popular, and have emerged as a good medium for communicating with the public. In this study, a comprehensive utilization of electronic public participation was used to analyze public opinion on a given nuclear-related decision-making process. The degree of deliberation and meditation of the public participating in an electronic poll survey was evaluated, and the decision-making factors representing the personal characteristics of the poll respondents such as age, income, education, residence, degree of knowledge and concern were carefully incorporated when preparing the poll-survey questionnaire for its evaluation. Fuzzy analysis was used to assess and aggregate the responses to each decision-making factor. As a case study, this procedure was used to analyzing public opinion on the location of a low-level radioactive waste disposal facility on the campus of Seoul National University. The results show that there is a tendency of respondents who are on the negative side of the argument to be more deliberate and meditative in their decision-making process than those on the positive side. Knowledge and residence were found to be important decision-making factors. 相似文献
96.
RM Bionta G Blewitt CB Bratton D Casper A Ciocio R Claus M Crouch ST Dye S Errede GW Foster W Gajewski KS Ganezer M Goldhaber TJ Haines TW Jones D Kielczewska WR Kropp JG Learned JM LoSecco J Matthews HS Park LR Price F Reines J Schulz S Seidel E Shumard D Sinclair HW Sobel JL Stone L Sulak R Svoboda G Thornton van der Velde JC C Wuest 《Canadian Metallurgical Quarterly》1987,36(1):30-36
97.
Zhihui Zhang Bing Q. Han Kyung H. Chung Enrique J. Lavernia 《Metallurgical and Materials Transactions A》2006,37(7):2265-2273
The current study aims to provide fundamental insight into the behavior of microstructures containing grain sizes that span
multiple length scales. A commercial 5083 Al alloy was selected as the material of interest to facilitate comparison with
recently published data. The materials studied here were prepared via the thermal consolidation of powders that were cryomilled
for different times (i.e., 0, 2, 4, and 8 hours). Following consolidation, the resultant microstructure was characterized by an equiaxed grain morphology
with a size distribution centered around 200∼300 nm. Dispersed among the 200- to 300-nm grains were coarse-grained regions
or ligaments with a grain size ranging from 600 nm to 2 μm. The occurrence of coarse-grained regions is rationalized on the
basis of recrystallization or subgrain coarsening, whereas the occurrence of equiaxed fine regions is proposed to be a result
of continuous grain growth. Two types of microstructures were selected for study, containing coarse-grained volumes of approximately
28 pct and 43 pct that corresponded to an ultimate tensile strength (UTS) of 566 MPa and 535 MPa, and a fracture strain of
3.2 pct and 3.5 pct, respectively. The observed ductility and the relevant toughening mechanisms were discussed in light of
the presence of multiple length scales. 相似文献
98.
Characterisation of a BioFET for detection of albumin in a mixture of human urine is presented. To avoid electrolyte effect of the urine, it was measured in PBS (phosphate buffer saline) at a fixed pH after albumin binding. The drain current was modulated by the albumin bound to the anti-albumin immobilised on the gate surface of the BioFET. The current variation ratio was likely to be proportional to the concentration of the albumin in the range 50-250 mg/1. The results show the feasibility of the BioFET as a urinary albumin sensor. 相似文献
99.
100.
Sang C. Park 《The Visual computer》2003,19(1):38-49
A sweeping operation called polygonal extrusion is defined to improve the modeling power of CSG-based modeling. It is assumed that a 2D cross-sectional polygon (sweeping
polygon) moves in space while its containing plane is kept orthogonal to the tangent direction of the trajectory curve, a planar
polygonal chain having no self-intersections. The objective of the paper is to compute the boundary of the swept volume of
the sweeping polygon as a set of polygons (or triangles). The most significant challenge to accomplishing this objective is
the problem of trimming the swept volume. To solve the trimming problem, 2D-curve offsetting methods are employed. Two algorithms
are presented for polygonal extrusion that are based on different offsetting methods, the Voronoi diagram and PWID offset.
The proposed algorithms have been implemented and tested with various examples.
Published online: 28 January 2003 相似文献