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31.
32.
紫坪铺泄洪洞穿越断层段新奥法设计与数值仿真分析 总被引:1,自引:0,他引:1
本文基于新奥法的基本原理 ,对紫坪铺水利工程 1 # 泄洪洞穿越 F3断层段的支护设计方案进行了有限元数值仿真分析和优化设计。分析结果表明 ,按照常规的支护不能保证围岩、支护的稳定。本文经过 4个支护方案的设计与仿真分析 ,提出了较为理想的支护方案 ;该支护方案已为工程实际所采用 ,取得了良好的实际效果。 相似文献
33.
石坚 《建筑科学与工程学报》1995,(3)
通过对原状、挤密黄土地基的有限元法计算及分析,探讨了原状黄土地基的变形、强度特征以及挤密对它的影响,得到了一些有益的结论。 相似文献
34.
Vizard CG Rimmer DL Pless-Mulloli T Singleton I Air VS 《The Science of the total environment》2006,370(1):61-69
A study of soil polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) concentrations was undertaken in the vicinity of a municipal solid waste incinerator (MSWI) in Newcastle upon Tyne as a result of concerns raised by local residents about potential contamination from fugitive and stack emissions. The study area was divided into four sectors (north-east (NE), south-east (SE), north-west (NW) and south-west (SW)) around the MSWI, and sampling sites were located up to a distance of 2.25 km. Based on air dispersion modelling, the sampling density was four times greater in the NE (downwind) sector compared to the SW (upwind) direction, and twice as great in the NW and SE sectors. PCDD/F concentrations found in soil samples ranged from 6 to 1911 ng I-TEQ/kg DW with a median of 32 ng I-TEQ/kg DW. There was no evidence of elevated concentrations downwind of the MSWI compared to other directions, nor of any trend in concentration at increasing distance from the MSWI. We concluded, therefore, that the MSWI fugitive and stack emissions were not a major source of PCDD/F contamination. Analysis of PCDD/F homologue profiles showed that samples exhibiting furan-dominated and OCDD-dominated profiles and a profile characteristic of the MSWI ash occurred in distinct clusters. Those samples showing the furan-dominated profile had the largest PCDD/F concentrations measured as I-TEQ, followed by samples with the incinerator profile, the deposition profile, and the OCDD-dominated profile. We identified some contamination hotspots located in the SW and SE sampling sectors (upwind of the MSWI), and potential sources for these hotspots were sought by using historic land use data from maps of the locality dating back to 1856. We concluded that the cluster of very high concentrations of PCDD/F in soils showing the furan homologue profile were most likely to have resulted from the disposal of graphite electrode sludges from brine electrolysis carried out at a chemical works between the 1890s and the 1930s. 相似文献
35.
Statistics is a branch of mathematics concerned with the collection, quantification, analysis, interpretation, and presentation
of real-world data, and the use of probability theory to estimate population parameters with these data. Spatial statistics is a subset of statistics that is concerned with handling the special problems associated with geographically distributed
data, which include spatial point patterns, regional and lattice measurement aggregations, irregularly spaced site-specific
measurements on a surface, and image analysis. Meanwhile, econometrics is concerned with the application of statistical methods
to the study of economic data and problems. When coining the term spatial econometrics in 1979, Paelinck and Klaassen characterized it as a subset of econometrics that is concerned with the role of spatial dependence
in regional economic model response and explanatory variables, asymmetries in spatial relationships, the specification of
geographic structure governing spatial interactions, and the explicit modeling of space. We outline and discuss principal
similarities (e.g., testing for the presence of spatial autocorrelation) and differences (e.g., map generalization) between
spatial statistics and spatial econometrics. In doing so, our goal is to help clarify past, present, and future relationships
between these two subfields. 相似文献
36.
Humic acid, which is a typical microbially refractory organic substance, was extracted from a landfill leachate. The humic acid solution (COD = 367 mg 1−1; TOC = 293 mg 1−1; BOD = 27 mg 1−1) was applied to a batch scale activated sludge treatment after the modification of its biodegradability by γ-ray irradiation. The BOD increased to 64 mg 1−1 by irradiation of 15 kGy (1.5 Mrad), while the COD and TOC decreased to 231 and 230 mg 1−1, respectively. When the irradiated sample was treated with an activated sludge, the BOD decreased rapidly in 2–3 h to about 15 mg 1−1 which was a similar value as the unirradiated sample was treated. The elimination efficiency of TOC by the sludge treatment was approximately equal to that obtained by irradiation of 15 kGy. These facts suggest a utility of applying microbial processes after radiation treatment of microbially refractory wastewaters. 相似文献
37.
On the measurement of comparative advantage 总被引:5,自引:0,他引:5
This paper shows that the standard measure of revealed comparative advantage (RCA), ranging from 0 to ∞, has problematic properties. Due to its multiplicative specification, it has a moving mean larger than its expected value of 1, while its distribution strongly depends on the number of countries and industries. These properties make its outcomes incomparable across time and place and its economic interpretation problematic. We propose an alternative measure, the additive RCA, ranging from −1 to +1, with a symmetric distribution that centers on a stable mean of zero, independent of the classifications used. Statistical tests show the distribution of the additive index to be more stable. Besides, we propose an aggregate RCA, a regional specialization index, ranging from 0 for pure intra-industry trade to 1 for pure inter-industry trade. The same conclusions and proposals hold for the multiplicative location quotient (LQ), which is used as a measure for the revealed locational attractiveness of certain regions or countries for certain types of industry.
相似文献
Jan OosterhavenEmail: |
38.
This paper extends the empirical literature on the effects of trade liberalization on regional disparities within a country. Studying the case of the Central and Eastern European countries, we find significant convergence of real wages in Poland and Bulgaria, only. Furthermore, countries with a faster growing export openness in the period 1991–1998 experienced larger increases in their regional disparities. Especially, intermediate goods trade seems to have been a main driving force. Our estimates suggest that the long run impact of rising intermediate goods export openness in the last decade was a 23% increase in the average economys variance of real wages.Received: December 2002/Accepted: January 2004The authors are grateful to two anonymous referees for their helpful suggestions. 相似文献
39.
Lubica Sobotova Jana Jurkovicova Ludmila Sevcikova 《The Science of the total environment》2010,408(6):1264-1270
Objective
The objective of our study was to investigate and evaluate the relationship between road traffic noise and cardiovascular risk.Methods
The study sample (n = 659; 36.9% male, 63.1% female university students, mean age 22.83 ± 1.58 years) included a group exposed to road traffic noise (n = 280, Leq,24 h = 67 ± 2 dB(A)) and a control group (n = 379, Leq,24 h = 58.7 ± 6 dB(A)). Subjective response was determined by a validated noise annoyance questionnaire. The ten year risk of developing a coronary heart disease event was quantified as an evaluation of cardiovascular risk (SCORE60, Framingham 10-year risk estimation and projection to the age of 60, relative risk SCORE chart).Results
Cardiovascular risk scores were significantly higher in the exposed group based on the Framingham scores projected to the age of 60, SCORE60 (AOR = 2.72 (95% CI = 1.21-6.15)) and the relative risk SCORE chart (AOR = 2.81 (1.46-5.41)).Conclusions
These findings highlight the association between road traffic noise and cardiovascular risk. 相似文献40.