全文获取类型
收费全文 | 4227篇 |
免费 | 18篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 15篇 |
综合类 | 3篇 |
化学工业 | 254篇 |
金属工艺 | 59篇 |
机械仪表 | 22篇 |
建筑科学 | 20篇 |
矿业工程 | 2篇 |
能源动力 | 19篇 |
轻工业 | 118篇 |
水利工程 | 14篇 |
石油天然气 | 4篇 |
无线电 | 69篇 |
一般工业技术 | 226篇 |
冶金工业 | 3295篇 |
原子能技术 | 25篇 |
自动化技术 | 101篇 |
出版年
2023年 | 8篇 |
2022年 | 9篇 |
2021年 | 10篇 |
2020年 | 8篇 |
2016年 | 10篇 |
2014年 | 23篇 |
2013年 | 49篇 |
2012年 | 41篇 |
2011年 | 46篇 |
2010年 | 41篇 |
2009年 | 37篇 |
2008年 | 37篇 |
2007年 | 35篇 |
2006年 | 36篇 |
2005年 | 32篇 |
2004年 | 39篇 |
2003年 | 35篇 |
2002年 | 38篇 |
2001年 | 23篇 |
2000年 | 24篇 |
1999年 | 112篇 |
1998年 | 923篇 |
1997年 | 514篇 |
1996年 | 331篇 |
1995年 | 210篇 |
1994年 | 162篇 |
1993年 | 228篇 |
1992年 | 49篇 |
1991年 | 63篇 |
1990年 | 59篇 |
1989年 | 72篇 |
1988年 | 58篇 |
1987年 | 64篇 |
1986年 | 64篇 |
1985年 | 75篇 |
1984年 | 15篇 |
1983年 | 12篇 |
1982年 | 25篇 |
1981年 | 47篇 |
1980年 | 36篇 |
1979年 | 14篇 |
1978年 | 15篇 |
1977年 | 122篇 |
1976年 | 264篇 |
1975年 | 19篇 |
1974年 | 15篇 |
1973年 | 14篇 |
1972年 | 8篇 |
1970年 | 7篇 |
1966年 | 8篇 |
排序方式: 共有4246条查询结果,搜索用时 396 毫秒
1.
Thioux Marc; Stark David E.; Klaiman Cheryl; Schultz Robert T. 《Canadian Metallurgical Quarterly》2006,32(5):1155
Some individuals are able to determine the weekday of a given date in a few seconds (finding for instance that June 12, 1900, was a Tuesday). This ability has fascinated scientists for many years because it is predominantly observed in people with limited intelligence and may appear very early in life. Exceptional visual memory, exceptional concentration abilities, or privileged access to lower levels of information not normally available through introspection have been advanced to explain such phenomena. In the present article, the authors show that a simple cognitive model can explain all aspects of the performance of Donny, a young autistic savant who is possibly the fastest and most accurate calendar prodigy ever described. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
2.
RE Vlietstra 《Canadian Metallurgical Quarterly》1993,16(10):2073-2074
3.
BF Habbick JL Nanson RE Snyder RE Casey AL Schulman 《Canadian Metallurgical Quarterly》1996,87(3):204-207
Ethers and thioethers of monosaccharides have been synthesised which show potent toxicity to mouse (LD50 > or = 4 g.kg-1 O.W. and 0.2 to 1.5 g.kg-1 I.P.W.). A study of calcium antagonist activity for the full series of compounds indicated that the activity was similar for both O- and S- ethers and maximum activities were observed for monoacetoneglucose ethers possessing carbon chain close to 8 carbons. 相似文献
4.
BACKGROUND: IgE-mediated hypersensitivity to latex proteins has become a significant clinical problem over the last decade. Nursing and medical staff are at risk because of their occupational exposure to latex. AIMS: To determine the prevalence of type I hypersensitivity to latex allergens in the nursing staff of an Australian hospital. METHODS: A questionnaire which asked about symptoms associated with the use of latex gloves was completed by 140 nurses working in the Alfred Hospital (72 in general medical wards, 68 in intensive care units). Skin prick tests with eluates of five different types of latex glove as well as common aeroallergens (rye pollen and house dust mite) and banana extract were performed. RESULTS: Thirty-one nurses (22%) were skin prick test positive to at least one of the five latex glove eluates. All of these nurses were atopic, having positive skin prick tests to rye pollen or house dust mite. Symptoms of local dryness, itch and erythema associated with glove use were reported by more than half the study group, but not more frequently by those who were skin prick test positive to latex. Urticaria associated with glove use was reported more frequently by those with positive latex skin prick tests (13% vs 4%, p = 0.05). Eighty-seven per cent of the nurses who were latex skin test positive were also positive to banana extract. CONCLUSIONS: IgE-mediated hypersensitivity to latex is common in nurses working in an Australian hospital. Glove associated symptoms were frequently reported, but in most cases the symptoms were more typical of irritant or contact dermatitis rather than type I hypersensitivity reactions. However, the extent of subclinical sensitisation to latex found in this study suggests that symptomatic latex allergy is likely to emerge as an increasing problem for nursing staff in this country. 相似文献
5.
6.
RE O'Carroll A Moffoot KP Ebmeier C Murray GM Goodwin 《Canadian Metallurgical Quarterly》1993,23(2):341-347
Eighteen patients suffering from Alcoholic Korsakoff's Syndrome participated in a placebo-controlled double-blind cross-over trial of clonidine 0.3 mg b.d. for two weeks versus matched placebo for two weeks. A detailed neuropsychological assessment was carried out at the end of each treatment phase and staff ratings of behaviour were also obtained. Clonidine treatment resulted in no significant improvement over placebo on any of the cognitive measures employed. The results contradict previous smaller studies which had suggested that chronic treatment with clonidine had a memory-enhancing effect in Korsakoff's syndrome. 相似文献
7.
The phenotypic characteristics of three Serpulina pilosicoli strains isolated from humans with diarrhoea (WesB, Kar, Hrm7) and two porcine S. pilosicoli strains isolated from pigs with intestinal spirochaetosis (1648, 3295), were compared with the type strain of the species P43/6/78T (T = type strain) and other intestinal spirochaetes within the genus Serpulina. All S. pilosicoli strains had a characteristic ultrastructural appearance, displayed similar growth rates, hydrolysed hippurate, lacked beta-glucosidase activity, utilised D-ribose as a growth substrate, and had similar sensitivities to rifampicin and spiramycin. The only consistent phenotypic characteristic that differentiated human strains from porcine strains of S. pilosicoli was that the human strains all utilised the pentose sugar D-xylose. These distinguishing phenotypic traits appear useful for identifying S. pilosicoli. 相似文献
8.
9.
M. Calin H. Grahl M. Adam J. Eckert L. Schultz 《Journal of Materials Science》2004,39(16-17):5295-5298
In this work the Al85Ni9Nd4Co2 alloy was used as a starting point for examining the possibility of forming bulk glassy Al-based materials by combining rapid quenching and ball milling techniques. Fine glassy powders were obtained by ball milling melt-spun amorphous ribbons using a severe cryogenic processing regime. The thermal stability data of the powders as obtained by constant-rate heating and isothermal DSC experiments together with viscosity measurements are discussed with respect to feasible consolidation conditions. The powder compaction was done by two methods (uni-axial hot pressing and extrusion) at 513 K for up to 15 min. Only the uni-axial hot pressing led to bulk Al85Ni9Nd4Co2 samples with similar glassy structure and Vickers microhardness values comparable to those of the initial melt-spun ribbons. 相似文献
10.
The Metaflow architecture, a unified approach to maximizing the performance of superscalar microprocessors, is introduced. The Metaflow architecture exploits inherent instruction-level parallelism in conventional sequential programs by hardware means, without relying on optimizing compilers. It is based on a unified structure, the DRIS (deferred-scheduling, register-renaming instruction shelf), that manages out-of-order execution and most of the attendant problems. Coupling the DRIS with a speculative-execution mechanism that avoids conditional branch stalls results in performance limited only be inherent instruction-level parallelism and available execution resources. Although presented in the context of superscalar machines, the technique is equally applicable to a superpipelined implementation. Lightning, the first implementation of the Metaflow architecture, which executes the Sparc RISC instruction set is described 相似文献