全文获取类型
收费全文 | 589篇 |
免费 | 12篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 73篇 |
金属工艺 | 15篇 |
机械仪表 | 8篇 |
建筑科学 | 16篇 |
矿业工程 | 2篇 |
能源动力 | 10篇 |
轻工业 | 53篇 |
水利工程 | 9篇 |
无线电 | 60篇 |
一般工业技术 | 79篇 |
冶金工业 | 196篇 |
原子能技术 | 4篇 |
自动化技术 | 72篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 7篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 8篇 |
2017年 | 6篇 |
2016年 | 6篇 |
2015年 | 4篇 |
2014年 | 9篇 |
2013年 | 20篇 |
2012年 | 20篇 |
2011年 | 18篇 |
2010年 | 13篇 |
2009年 | 15篇 |
2008年 | 16篇 |
2007年 | 14篇 |
2006年 | 20篇 |
2005年 | 19篇 |
2004年 | 19篇 |
2003年 | 6篇 |
2002年 | 13篇 |
2001年 | 13篇 |
2000年 | 8篇 |
1999年 | 12篇 |
1998年 | 68篇 |
1997年 | 39篇 |
1996年 | 18篇 |
1995年 | 16篇 |
1994年 | 16篇 |
1993年 | 14篇 |
1992年 | 10篇 |
1991年 | 9篇 |
1990年 | 2篇 |
1989年 | 15篇 |
1988年 | 12篇 |
1987年 | 14篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 14篇 |
1975年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有601条查询结果,搜索用时 31 毫秒
81.
Structural stereopsis for 3-D vision 总被引:1,自引:0,他引:1
Boyer K.L. Kak A.C. 《IEEE transactions on pattern analysis and machine intelligence》1988,10(2):144-166
82.
Raymond F. Boyer 《Polymer Engineering and Science》1979,19(10):732-748
The accomplishments of Borden Award Winner John K. Gillham and his colleagues using Torsional Braid Analysis (TBA) and Differential Scanning Calorimetry (DSC) to investigate the Tg and T > Tg or Tu regions of anionic and thermal poly styrenes (PS) are evaluated and related to work on PS and other polymers and to controversies surrounding TBA and the Tu transition. Arguments are presented to refute the contention that Tu by TBA is an artifact produced by the braid and the contention that Tu has a relaxational nature but no thermodynamic basis. Two distinct behavior patterns are found for Tu vs log M?n plots: quasi-static methods such as DSC on fused films show Tu to level off above Mc and approach an asymptotic value of ~435K; dynamic methods involving melt flow show that Tu increases without limit above Mc because of entanglements. A compilation is presented of 25 investigations of Tu on polybutadiene, poly(methyl methacrylate) (PMMA), PS, plasticized PS, and atactic polypropylene, involving twenty experimental techniques. The behavior of zero shear melt viscosity for PS is summarized. Gillham's work has not only led to clarification of many isolated papers in the literature but has also inspired various parallel experimental and literature studies on Tu. We conclude that Tu is a molecular level transition which, like Tg, exhibits both kinetic (relaxational) and thermodynamic aspects. It is shown that heat capacity should be a more sensitive method than dilatometry for studying the Tu transition. 相似文献
83.
B Wang J Boyer V Srikantan L Coney R Carrano C Phan M Merva K Dang M Agadjanan L Gilbert 《Canadian Metallurgical Quarterly》1993,12(9):799-805
DNA, or genetic, inoculation mimics aspects of attenuated vaccines in that synthesis of specific foreign proteins is accomplished in the host. These proteins can be processed and presented on the relevant major histocompatibility complex (MHC) antigens and ultimately become the subject of immune surveillance. Very recently, we have described the use of the new technology to generate immune responses in mice against the human immunodeficiency virus type 1 (HIV-1) envelope using a gp160 DNA construct. Further analysis of this technology specifically in regard to HIV vaccine design is clearly important. In this report, we describe the analysis of additional HIV constructs as immunogens in both mice and report the use of this genetic immunization technology in nonhuman primates. In these studies, successful seroconversion occurs in more than 70% of the mice following the second immunization with 100 micrograms of construct DNA; three and four immunizations result in routinely 100% seroconversion of the mice. Furthermore, the same strategy has successfully seroconverted primates following their second inoculation, resulting in the generation of both antiviral and neutralizing antibodies in this animal species. These studies are the first report of which we are aware that demonstrate successful immunization of nonhuman primates through genetic vaccination technology and the first to describe genetic immunization of primates against HIV antigens. This technology has relevance for the development of safe and efficacious immunization strategies against HIV because it provides for relevant antigen production in vivo without the use of infectious agents. 相似文献
84.
Boyer K.L. Sarkar S. 《IEEE transactions on pattern analysis and machine intelligence》1994,16(1):106-108
Tagare and deFigueiredo (see ibid., vol. 12, p. 1186-1189, 1990 ) present a localization performance measure for edge detectors. They correctly point out a flaw in Canny's formulation of the localization criterion, which was subsequently adopted by Sarkar and Boyer (1991). They motivate their form of the localization criterion along a different line of reasoning. In this comment, the authors show that although Canny's derivation was in error, the final form of his criterion is adequate and can, in fact, be derived from Tagare and deFigueiredo's formulation of the problem. The authors also point out some problems with Tagare and deFigueiredo's localization criterion 相似文献
85.
GS Dean L Pusztai FJ Xu K O'Briant K DeSombre M Conaway CM Boyer J Mendelsohn RC Bast 《Canadian Metallurgical Quarterly》1998,4(10):2545-2550
Approximately 30% of ovarian and breast cancers overexpress p185(c-erbB-2) with as many as 10(6) receptors/cell. Normal cells have as few as 10(4) receptors/cell. We have examined the susceptibility of SKOv3 human ovarian cancer cells to anti-c-erbB2 antibodies and immunotoxins as a function of c-erbB-2 density on the cell surface. A panel of SKOv3 clones that expressed different densities of p185(c-erbB-2) receptor were generated through transfection with the c-erbB-2 gene. A significant correlation was found between p185(c-erbB-2) density and susceptibility to killing by anti-p185(c-erbB-2)-ricin A chain (anti-p185(c-erbB-2)-RTA) immunotoxins. With 10(5) copies/cell of p185(c-erbB-2), <10% of clonogenic ovarian cancer cells could be eliminated, whereas in clones that expressed 10(6) copies/cell of p185(c-erbB-2), 99.9% of clonogenic tumor cells were killed. In cell lines that overexpressed p185(c-erbB-2) and also expressed p170(EGFR), anti-p185(cerbB-2)-RTA and anti-p170(EGFR)-RTA immunotoxins exerted synergistic cytotoxicity. Treatment with the two immunotoxins could eliminate 99.99% of clonogenic cells. Importantly, tumor cells that had survived first treatment with anti-p185(c-erbB2)-RTA alone still retained sensitivity to repeat treatment with the same immunotoxin and also proved susceptible to the synergistic cytotoxicity of anti-p185(cerbB-2)-RTA in combination with anti-p170(EGFR)-RTA. Growth characteristics of the clones expressing various levels of p185(c-erbB-2) were also studied. No correlation was found between p185(c-erbB-2) expression levels and the rate of anchorage-dependent growth, anchorage-independent growth, or in vivo growth in nude mice. 相似文献
86.
87.
This paper describes a first attempt to base a paraphrase generation system upon Meľčuk and Žolkovskij's linguistic meaning-text (MT) model whose purpose is to establish correspondences between meanings, represented by networks, and (ideally) all synonymous texts having this meaning. The system described here contains a Prolog implementation of a small explanatory and combinatorial dictionary (the MT lexicon) and, using unification and backtracking, generates from a given network the sentences allowed by the dictionary and the lexical transformations of the model. The passage from a net to the final texts is done through a series of transformations of intermediary structures that closely correspond to MT utterance representations (semantic, deep-syntax, surface-syntax, and morphological representations). These are graphs and trees with labeled arcs. The Prolog unification (equality predicate) was extended to extract information from these representations and build new ones. The notion of utterance path, used by many authors, is replaced by that of covering by defining subnetworks. 相似文献
88.
RA Nicholas ER Lazarowski WC Watt Q Li J Boyer TK Harden 《Canadian Metallurgical Quarterly》1996,16(6):319-323
An autopsy case of a 67-year-old man with typical clinical features of progressive supranuclear palsy (PSP) characterized by impairment of vertical ocular pursuit movement, pseudobulbar palsy, nuchal stiffness, parkinsonism, and dementia is described. In addition to typical pathological changes of PSP, the present case showed fronto-temporal cortical atrophy, accompanied with various Gallyas/tau-positive neuronal and glial structures such as neurofibrillary tangles, pretangle neurons, glial coiled bodies, astrocytic plaques and argyrophilic threads in the cerebral cortex and subcortical nuclei, and many senile plaques throughout the whole cerebral cortex. The present report suggests that PSP and corticobasal degeneration share a common background in neuronal and glial pathologies, that pathological changes of PSP and Alzheimer's disease are mixed in the entorhinal cortex, amygdala. Meynert nucleus, and hypothalamus, and that dementia with frontal lobe-like syndrome in PSP is related to the frontal and temporal cortical pathologies, and is cortical dementia as well as subcortical dementia. 相似文献
89.
90.
By starting from the theory of Mayadas and Shatzkes, a model for the effect of grain boundaries on the electrical conductivity of an intrinsic semimetal is proposed. The influence of the size of crystallites on the electrical conductivity of polycrystalline antimony films is studied theoretically and experimentally.
Excellent agreement is obtained over a large temperature range (10–500 K) for various sizes of crystallites (100–2000 Å). 相似文献