全文获取类型
收费全文 | 794篇 |
免费 | 40篇 |
专业分类
电工技术 | 12篇 |
综合类 | 3篇 |
化学工业 | 172篇 |
金属工艺 | 24篇 |
机械仪表 | 11篇 |
建筑科学 | 69篇 |
矿业工程 | 4篇 |
能源动力 | 24篇 |
轻工业 | 172篇 |
水利工程 | 4篇 |
无线电 | 45篇 |
一般工业技术 | 123篇 |
冶金工业 | 94篇 |
原子能技术 | 1篇 |
自动化技术 | 76篇 |
出版年
2023年 | 4篇 |
2021年 | 20篇 |
2020年 | 18篇 |
2019年 | 22篇 |
2018年 | 22篇 |
2017年 | 24篇 |
2016年 | 17篇 |
2015年 | 25篇 |
2014年 | 28篇 |
2013年 | 67篇 |
2012年 | 39篇 |
2011年 | 54篇 |
2010年 | 40篇 |
2009年 | 30篇 |
2008年 | 38篇 |
2007年 | 31篇 |
2006年 | 42篇 |
2005年 | 26篇 |
2004年 | 23篇 |
2003年 | 16篇 |
2002年 | 17篇 |
2001年 | 13篇 |
2000年 | 9篇 |
1999年 | 8篇 |
1998年 | 16篇 |
1997年 | 14篇 |
1996年 | 7篇 |
1995年 | 14篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 11篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 11篇 |
1985年 | 5篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1978年 | 5篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1959年 | 3篇 |
排序方式: 共有834条查询结果,搜索用时 15 毫秒
51.
This study investigated the enactment effect from the perspective of the item-order hypothesis (e.g., M. Serra & J. S. Naime, 1993). The authors assumed that in subject-performed tasks (SPTs), item encoding is improved but order encoding is disrupted compared with experimenter-performed tasks (EPTs), that order encoding of EPTs is only better in pure lists, and that the item-order hypothesis is confined to short lists. Item information was tested in recognition memory tests, order information in order reconstruction tasks, and both item and order information in free-recall tests. The results of 5 experiments using short (8 items) and long lists (24 items) in a design with list type (pure, mixed) and encoding condition (EPT, SPT) as factors supported the hypotheses. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
52.
Harald A. Øye Barry J. Welch 《JOM Journal of the Minerals, Metals and Materials Society》1998,50(2):18-23
There have been tremendous advances in the materials, knowledge, design, and construction of cathodes; however, widelydivergent cell operations and operating conditions present a challenge for selecting the right materials and lining design for good cell life. Cathode wear is frequently becoming the life-determining step, and, although there are questions still to be answered, it is probable that particulate detachment (physical wear) plays an important role in parallel with carbide dissolution. If wear cannot be controlled by smart design and operations, coating technology may offer benefits for extending the life of cathode linings by reducing or eliminating wear. Thus, it would also enable softer graphitic materials to be utilized more readily, and this advantage will become more important if the trend toward higher current density continues. 相似文献
53.
Hepatitis C (HCV) is a serious infection caused by a blood-borne virus. It is a contagious disease spreading via a variety
of transmission mechanisms including contaminated tattoo equipment. Effectively regulating commercial tattoo parlours can
greatly reduce this risk. This paper models the cost-effectiveness and optimal timing of such interventions, and parameterises
the model with data for Vienna, Austria. This dynamic model of the contagious spread of HCV via tattooing and other mechanisms
accounts for secondary infections and shows that regulating tattoo parlours as done in Vienna, Austria in 2003, is a cost-saving
intervention. 相似文献
54.
György Csaba Paolo Lugli Markus Becherer Doris Schmitt-Landsiedel Wolfgang Porod 《Journal of Computational Electronics》2008,7(3):454-457
This paper presents a computational study of ion-beam patterned cobalt-platinum multilayers, which could be used for field-coupled
computing. We use micromagnetic simulations to reproduce measured hysteresis curves. This parameterized micromagnetic simulator
then will be used for simulating interacting magnetic dots. We demonstrate how logic gates can be built from such coupled
dots. We also show how electrical wires—placed beneath or above the magnetic dots—can provide a magnetic field, which propagates
the magnetic signals. 相似文献
55.
Franz Ferdinand Reinthaler Gebhard Feierl Herbert Galler Doris Haas Eva Leitner Franz Mascher Angelika Melkes Josefa Posch Ingrid Winter Gernot Zarfel Egon Marth 《Water research》2010,44(6):1981-1985
The aim of this study was to investigate the degree of contamination of sewage sludge with ESBL-producing Escherichia coli strains and the effectiveness of different sewage sludge treatment methods.Monthly sewage sludge samples were collected between January and September 2009 in 5 different sewage treatment plants and tested for the presence of ESBL E. coli. In addition, the number of colony forming units (CFU) of E. coli and coliform bacteria before and after the different sludge treatment methods (aerobic/anaerobic digestion, lime stabilization, and thermal treatment) was investigated.Of the 72 sewage sludge samples investigated, ESBL-positive E. coli were found in 44 (61.1%) sewage sludge samples. The classification of β-lactamase groups was carried out in 15 strains resulting in the detection of 2 different groups (CTX-M and TEM) of bla genes. All 15 of them had a CTX-M gene and 4 of these strains furthermore carried a TEM gene.With regard to the CFU of E. coli and coliform bacteria, thermal treatment and lime stabilization following dehydration sufficiently reduced pathogen concentrations. The plants using merely stabilization and dehydration showed an increase of E. coli and coliform bacteria and thus also an increase in ESBL-producing E. coli. 相似文献
56.
57.
58.
Element contents in leaves of four plant species (birch, mountain ash, fern and spruce) along anthropogenic and geogenic concentration gradients 总被引:2,自引:0,他引:2
Reimann C Arnoldussen A Boyd R Finne TE Koller F Nordgulen Ø Englmaier P 《The Science of the total environment》2007,377(2-3):416-433
Forty samples each of leaves of birch (Betula pubescens Ehrh.), European mountain ash (Sorbus aucuparia (L.)) and bracken fern (Pteridium aquilinum (L.) Kuhn) as well as spruce needles (Picea abies (L.) Karsten) were collected along a 120 km south-north transect running through Norway's largest city, Oslo. Concentrations of 25 chemical elements (Ag, Au, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sr, Ti, and Zn) as well as loss on ignition for the 4 sample materials are reported. The decline of input of sea spray with distance from the coast, geology, pH and anthropogenic contamination all played a role for the observed element concentrations in the leaves. Although growing under exactly the same natural conditions each plant species displayed quite unique uptake characteristics. Plant-species dependency and individual differences in the reaction of the plant leaves to different element sources make the investigated species of very limited value as bioindicators of anthropogenic activities. Anthropogenic contamination influences plant-leaf element content within a limited distance ( approximately 20 km) from the source. 相似文献
59.
Østlie HM Eliassen L Florvaag A Skeie S 《International journal of food microbiology》2004,94(3):287-299
Microbiological sampling of Norvegia cheese from three cheese factories was done during ripening. The evolution of aerobic mesophilic bacteria, lactococci, lactobacilli, enterococci, presumptive leuconostoc and pediococci was investigated after 30, 90, 180 and 270 days of ripening. Isolates (135) of non-starter lactic acid bacteria (NSLAB) from nine Norvegia cheeses after 90, 180 and 270 days of ripening were examined. The isolates were tested by physiological and biochemical assays, species-specific PCR and 16S rDNA sequencing. After 90 days of ripening Leuconostoc spp., most probably from the starter, and the NSLAB specie Lactobacillus paracasei dominated among the isolates, however, after longer ripening Lb. paracasei dominated. The development and evolution of the microflora in Norvegia varied according to dairy and ripening time. 相似文献
60.
Michael C. H. Hui Doris Yau 《Frontiers of Architecture and Civil Engineering in China》2011,5(4):405-414
The first “modern” type of vehicular bridge was built in Hong Kong China in the 1920s. The need for an efficient transportation
system to cope with population growth and enable economic development has demanded the construction of more and more bridges
since the middle of the 20th century. By 2007, Hong Kong had a total of about 1300 vehicular bridges. Four of these bridges,
including the Tsing Ma Bridge, Kap Shui Mun Bridge, Ting Kau Bridge, and the cable-stayed bridge on the Hong Kong-Shenzhen
Western Corridor, are considered to be major bridges supported by cables. Currently, the Stonecutters Bridge on Route No.
8 is under construction and is expected to be completed in late 2009. At the same time, the Hong Kong-Zhuhai-Macao Bridge
will be in its detailed design stage soon. While efforts have been made by bridge builders to construct these giant structures,
the upkeeping of these valuable assets at a high standard and ensuring their continuous functioning and performance during
their intended lifespans will be another important task for bridge engineers. Wind and structural health monitoring system
(WASHMS) will play a key role in this respect. 相似文献