全文获取类型
收费全文 | 6048篇 |
免费 | 192篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 86篇 |
综合类 | 4篇 |
化学工业 | 711篇 |
金属工艺 | 63篇 |
机械仪表 | 99篇 |
建筑科学 | 102篇 |
矿业工程 | 8篇 |
能源动力 | 118篇 |
轻工业 | 493篇 |
水利工程 | 16篇 |
石油天然气 | 14篇 |
无线电 | 181篇 |
一般工业技术 | 772篇 |
冶金工业 | 3125篇 |
原子能技术 | 10篇 |
自动化技术 | 440篇 |
出版年
2023年 | 21篇 |
2021年 | 59篇 |
2020年 | 56篇 |
2019年 | 66篇 |
2018年 | 115篇 |
2017年 | 108篇 |
2016年 | 139篇 |
2015年 | 101篇 |
2014年 | 144篇 |
2013年 | 326篇 |
2012年 | 205篇 |
2011年 | 217篇 |
2010年 | 181篇 |
2009年 | 127篇 |
2008年 | 137篇 |
2007年 | 120篇 |
2006年 | 96篇 |
2005年 | 57篇 |
2004年 | 35篇 |
2003年 | 54篇 |
2002年 | 41篇 |
2001年 | 31篇 |
2000年 | 38篇 |
1999年 | 142篇 |
1998年 | 1025篇 |
1997年 | 608篇 |
1996年 | 399篇 |
1995年 | 197篇 |
1994年 | 214篇 |
1993年 | 205篇 |
1992年 | 46篇 |
1991年 | 33篇 |
1990年 | 39篇 |
1989年 | 40篇 |
1988年 | 39篇 |
1987年 | 27篇 |
1986年 | 24篇 |
1985年 | 49篇 |
1984年 | 35篇 |
1983年 | 34篇 |
1982年 | 45篇 |
1981年 | 53篇 |
1980年 | 54篇 |
1979年 | 26篇 |
1978年 | 31篇 |
1977年 | 104篇 |
1976年 | 180篇 |
1975年 | 16篇 |
1973年 | 15篇 |
1972年 | 14篇 |
排序方式: 共有6242条查询结果,搜索用时 15 毫秒
1.
I. Budić-Leto T. Lovrić J. Gajdoš Kljusurić I. Pezo U. Vrhovšek 《European Food Research and Technology》2006,222(3-4):397-402
Identification of anthocyanins in the wine made of the Croatian autochthonous grape variety of Babić (Vitis vinifera L.) was carried out and their profile was determined by means of high-performance liquid chromatography with diode array
and mass spectrometric detection. Dependence of anthocyanins content and profile on maceration treatment conditions was investigated.
Statistically significant differences of anthocyanins concentration in wines Babić produced by various maceration treatments
were confirmed by the use of multivariate analysis of variances. The investigation results indicated that the maceration temperature
exerts higher influence on anthocyanins concentration than the duration of maceration. In addition, on the basis of anthocyanin
composition and using different multivariate statistical analyses, differentiation of wines Babić according to maceration
treatments was procured. 相似文献
2.
Math1 is essential for genesis of cerebellar granule neurons 总被引:1,自引:0,他引:1
N Ben-Arie HJ Bellen DL Armstrong AE McCall PR Gordadze Q Guo MM Matzuk HY Zoghbi 《Canadian Metallurgical Quarterly》1997,390(6656):169-172
3.
4.
ZnO-based varistor samples were prepared by the direct mixing of the constituent phases (DMCP) and sintering at 1100 °C for 2 h. The influence of the starting powder mixture's composition – the amounts of the pre-reacted varistor compounds and their composition – and its preparation, either with or without mechano-chemical activation (MCA), on the microstructure, phase composition and electrical characteristics of the varistor samples was studied. It showed that MCA improved the density and microstructural homogeneity of the varistor samples. MCA strongly affected the grain growth: it enhanced the nucleation of inversion boundaries (IBs) in the ZnO grains and the IBs-induced grain-growth mechanism resulted in uniform grain growth and hence a microstructure with smaller ZnO grains and a narrower grain size distribution. The final phase composition of the samples prepared by the DMCP method mainly depended on the presence of varistor dopants that can prevent the formation of the pyrochlore phase, especially Cr2O3, while MCA can affect it mostly by providing a homogeneous distribution of those dopants. The DMCP varistor samples prepared with MCA had much better current–voltage characteristics than the samples of the same composition prepared from unactivated powders. 相似文献
5.
Dragan Simić Svetlana Simić 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2007,11(12):1185-1192
A concept of business intelligent system for financial prediction is considered in this paper. It provides data needed for
fast, precise and good business decision support to all levels of management. The aim of the project is the development of
a new online analytical processing oriented on case-based reasoning (CBR) where a previous experience for every new problem
is taken into account. Methodological aspects have been tested in practice as a part of the management information system
development project of “Novi Sad Fair”. A case study of an improved application of CBR in prediction of future payments is
discussed in the paper.
This paper is originally presented at The International Conference on Hybrid Information Technology 2006, at the special session
on “Intelligent Information Systems for Financial Engineering”, November 2006 in Cheju Island, Korea. 相似文献
6.
PURPOSE: The purpose of this analysis was to appreciate the management of visually handicaped children outside specialized structures. We also assessed relays between primary physicians, hospitals and specialized structures. METHOD: A 12-question survey was sent to 144 liberal ophthalmologists of the North of France. The questionnary included 12 questions. We compared the results to litterature. RESULTS: The response-rate was 59.6%. This study indicated that the observed children by the liberal ophtalmologists had more simple diseases than in specialized structures. In hospitals, it seemed that the ophtalmologists diagnosed more severe diseases. These practitioners diagnosed some of these diseases. However some of diagnosis were to late. This study showed that specialized structures were not enough known by the practitioners who detected this handicap and that the families prefered the taking in charge near their home. CONCLUSION: We demonstrated the necessary organisation of precocious and systematic detection, and the necessary information to all practitioners on specialized structures. 相似文献
7.
8.
Flow cytometry is a unique technology useful in the examination of effects of immunotoxic agents on target cells of the immune system. The purpose of this workshop was to provide an overview of the use of flow cytometry in new and established models of immunotoxicity, with emphasis on the potential applications, assay validation, and potential pitfalls. This overview begins with a discussion of methods useful in the assessment of Ca2+-dependent mechanisms of lymphoid cell activation in surface marker-defined human B cells, T cells, and monocytes. A discussion of the use of flow cytometry in analysis of apoptosis is also presented in this paper. The second paper presents data on the development and use of flow cytometry as an alternative to a Cr51 release assay for an assessment of cytotoxic T cell activation. The use of surface markers for characterizing and distinguishing the effects of chemical irritants from sensitizers is next presented, followed by an overview of the use of fluorescent probes to assess cell thiol status and overall oxidant-induced injury to lymphoid cells. Finally, an interlaboratory study designed to compare and evaluate the use of flow cytometry procedures in rat splenic cell subtyping is presented. Overall, these studies demonstrate the utility of flow cytometry assays in immunotoxicologic research, but further efforts are needed in the validation of many of these assays for routine use in immunotoxicologic testing. 相似文献
9.
O Hanisch CA Cortella MM Boskovic RA James J Slots UM Wikesj? 《Canadian Metallurgical Quarterly》1997,68(1):59-66
Factor V Leiden mutation was initially detected in thrombophilic patients and relatives by PCR RFLP (Restriction Fragment Length Polymorphism) according to Bertina (1). This technique presents some drawbacks and the current trend is to simplify the diagnosis. We describe a technique of Allele Specific Amplification (ASA) which is optimized in terms of reliability: an additional mismatch in antepenultimate position enables to obtain the same specificity as PCR RFLP. Furthermore, coamplification of internal control warrants an optimal sensitivity. All the PCR have been simplified: the DNA extraction improvement allows to analyse the genotype with only a few microliters of whole blood whatever the anticoagulant and the procedure of preservation (freezing, dried blood spots, storage at +4 degrees C for several days). This technique saves time. Moreover, full automation of the ASA technique may be shortened thanks to the lack of extraction and the positive/negative reading of the PCR signal. 相似文献
10.