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561.
C. Kapsalis B. Sagebiel 《经济导报》2010,(1):66-68
对于海上结构物而言。其所处的飞溅区是腐蚀最为严重的区域,而铜镍合金已经在该区域的海上结构物防护中获得了成功。其中合金400(N04400,NiCu7030)的应用历史最长 相似文献
562.
V.N. Agostini A.N. Hendrix A.B. Hollowed C.D. Wilson S.D. Pierce R.C. Francis 《Journal of Marine Systems》2008,71(3-4):237
Climate forcing of the California Current has been known to impact the distribution and abundance of a number of local fish populations, but the mechanisms involved remain poorly understood. Climate metrics such as the Pacific Decadal Oscillation (PDO) and the El Niño Southern Oscillation (ENSO) are usually used to represent climate processes and direct links are made between climate forcing and production variability. This involves aggregation of impacts across large spatial scales and range of species. However, fluctuations in productivity are often the result of changes in physical habitat. In order to fully understand the relationship between climate and productivity, habitat changes should be addressed. In this study we use a geostatistical approach to quantify adult Pacific hake habitat during different climate regimes. Several authors have suggested that the distribution and intensity of the sub-surface poleward flow (the undercurrent) plays a key role in defining adult hake habitat along the west coast of North America. Here we build a model designed to predict hake habitat distribution in space based on sub-surface poleward flow distribution and bottom depth. Our results show that hake habitat expands in 1998 El Niño year compared to 1995. Given the important predatory role that hake plays in the CC, the amount and distribution of adult hake habitat has large implications for the Pacific Northwest food web and could thus serve as an ecosystem indicator representing important physical–biological interactions. Spatially based ecosystem indicators such as the one we develop here address two important yet neglected areas in the ‘Ecosystem Indicators debate’: the importance of developing metrics explicitly representing spatial and environmental processes shaping ecosystem structure. Without these, our power to fully describe ecosystems will be limited. 相似文献
563.
C. Raick A. Alvera-Azcarate A. Barth J.M. Brankart K. Soetaert M. Grgoire 《Journal of Marine Systems》2007,65(1-4):561
The Singular Evolutive Extended Kalman (SEEK) filter has been implemented to assimilate in-situ data in a 1D coupled physical-ecosystem model of the Ligurian Sea. The biogeochemical model describes the partly decoupled nitrogen and carbon cycles of the pelagic food web. The GHER hydrodynamic model (1D version) is used to represent the physical forcings. The data assimilation scheme (SEEK filter) parameterizes the error statistics by means of a set of empirical orthogonal functions (EOFs). Twin experiments are first performed with the aim to choose the suitable experimental protocol (observation and estimation vectors, number of EOFs, frequency of the assimilation,…) and to assess the SEEK filter performances. This protocol is then applied to perform real data assimilation experiments using the DYFAMED data base. By assimilating phytoplankton observations, the method has allowed to improve not only the representation of the phytoplankton community, but also of other variables such as zooplankton and bacteria that evolve with model dynamics and that are not corrected by the data assimilation scheme. The validation of the assimilation method and the improvement of model results are studied by means of suitable error measurements. 相似文献
564.
In this paper time series univariate forecast methods and analysis of time series is used in an innovative way, with the intention
of assisting the flag state administrators to map and predefine their shipping quality policy. In general, given the number
of ships detained by Port State Control (PSC) and corresponding inspections of the flag fleet for the same period of time,
one is able to forecast the Paris Memorandum of Understanding (Paris MoU) excess factor of any flag state for a selected time
window. Thus, depending on the goals of each flag state administration, one can judge their feasibility (e.g. remain in the
Paris MOU White List or achieve an excess factor of —1 etc) and determine whether to enhance the safety measures or not. The
method is first developed and discussed on an abstract basis to set the theoretical background, a combination of time series
analysis and practical engineering philosophy. Then the study focuses upon the Cyprus Flag figures in Paris MOU ports, only
to demonstrate its effectiveness but can in any case be applied upon any given flag. The application of the method suggested,
combined with expert judgment, could result in a significant improvement of the flag quality. 相似文献
565.
Intelligent Transport Systems (ITS) have a wide range of applications. They range from the more traditional signal coordination system to concepts such as smart cars and smart roads. This paper describes transit‐based ITS measures in Singapore. The island‐state has plans to double the current 90 km rail network over the next ten years and has also implemented or committed to implement many ITS initiatives that impact upon the public transport systems. The aim of these investments is to achieve a high transit modal share using a comprehensive transit network. ITS measures that can promote this aim include: automatic vehicle location systems for buses and taxis, integrated transit fare systems using contactless smart cards, rail information systems, multi‐modal travel guides on Internet and electronic road pricing. The potential impacts of these measures are delay reduction, more comfort, productivity gain and better network accessibility. ITS measures do not necessarily add physical capacity to a public transport system but are excellent supporting measures to encourage the modal shift to transit, particularly if a quality transit system is already in place. 相似文献
566.
Effect of wave boundary layer on sea-to-air dimethylsulfide transfer velocity during typhoon passage
A full-spectral third-generation ocean wind–wave model (Wavewatch-III) implemented in the South China Sea is used to investigate the effects of the wave boundary layer on the drag coefficient and the sea-to-air transfer velocity of dimethylsulfide (DMS) during passage of Typhoon Wukong (September 5–11, 2000) with a maximum sustained wind speed of 38 m s− 1. The model is driven by the reanalyzed surface winds (1° × 1°, four times daily) from the National Centers for Environmental Prediction. It is found that the wave boundary layer evidently enhances (16.5%) the drag coefficient (in turn increases the momentum flux across the air–sea interface), and reduces (13.1%) the sea-to-air DMS transfer velocity (in turn decreases the sea-to-air DMS flux). This indicates the possibility of important roles of wave boundary layer in atmospheric DMS contents and global climate system. 相似文献
567.
J. Gonzalez-Feliu C. Ambrosini F. Henriot J. -L. Routhier 《Recherche - Transports - Sécurité》2012,28(2):88-100
In this paper, we are putting forward a methodology and results from a simulation of different town development scenarios, aimed at reducing the impact of greenhouse gas production from the exchange of goods by 75%. The state-of-the-art scenarios are designed based on combining elements relating to recent planning work on town transport systems in France, and empirical results based on surveys and urban logistics modelling work. It shows a set of relevant determinants of potential changes in the formation of goods flows within the town. Based on the fact that, in France, more than half of the car-equivalent vehicle-km produced by the transportation of goods are as a result of households using their cars to go shopping, the scenarios are designed according to a systematic approach to urban mobility of goods and people. They bring together organisational aspects (changes to the urban goods movement system) and aspects of planning and land use, especially with regard to flow generators such as factories, warehouses, shops and households. The calculations, allowing the measurement of the impact of these scenarios on the production of greenhouse gases, are carried out using a model that combines the changes between economic production activities on the one hand, and the changes to household purchases on the other. As a result, organisational changes are proving to be an essential addition to a policy for increasing the density of the urban fabric. 相似文献
568.
Adjo A. Amekudzi C. Jotin Khisty Meleckidzedeck Khayesi 《Transportation Research Part A: Policy and Practice》2009,43(4):339-348
A review of the sustainability literature reveals the lack of viable frameworks and management tools that can be used to accommodate both spatial and temporal variability in how stakeholder entities meet their sustainable development goals, taking into account the fact that different entities may need to pursue different priorities and also deal with different constraints and schedules at different stages of their development. This paper presents a sustainability footprint framework and model that may be used in analyzing the impacts of transportation and other infrastructure systems on regional sustainable development. A specific application of the framework is in the quality of life contributions that transportation systems may make to communities as a function of their impacts on natural assets that contribute inputs and absorb the byproducts of development. The application is illustrated in a case study that uses data from the Atlanta and Chicago Metropolitan Areas to demonstrate how this model may be applied in real life situations. The implications of this model for transport systems research, policy and practice are discussed. The value of this framework and model lie in introducing both spatial and temporal flexibility that may enable stakeholders with widely different priorities to reach consensus on interim goals for sustainable development to ultimately attain sustainability. 相似文献
569.
Kaviyarasu Yellappan Kulanthayan K.C. Mani Shamsul Bahri Md. Tamrin 《国际交通安全学会研究报告》2019,43(3):153-160
This study aims to identify the determinants of certified helmet use among postal delivery riders (PDRs) in rural areas of Peninsular Malaysia. A cross-sectional study was done among 269 PDRs from 50 postal distribution centres (DC) nationwide. Data collection was achieved through observation of the helmets and a questionnaire. The quality of the motorcycle helmets was determined by the presence of the certification label issued by the Standards and Industrial Research Institute of Malaysia (SIRIM). The response rate was 99.3%. The odds of full-shell helmets having the SIRIM label were 37.1 times more than that of the half-shell helmets. The odds of non-purchased helmets having the SIRIM label were 14.9 times more than that of the purchased helmets. The odds of expensive helmets having the SIRIM label were 4.4 times more than that for cheaper motorcycle helmets. The odds of helmets owned by riders without a previous crash history having the SIRIM label were 1.9 times more than helmets owned by riders with a crash history. Full-shell helmets with SIRIM standard certification, non-purchased helmets, helmet price of US$11.00 or more, and motorcycle riders without any previous crash history were determinants that contributed towards the use of a certified motorcycle helmet. Multiple logistic regression indicated that two variables significantly predicted the use of a certified motorcycle helmet among PDRs – helmet type and cost. An employer that provides the employees with full-shell motorcycle helmets with SIRIM standard certification label that costs at least US$11.00 and hiring motorcycle riders without any previous crash history gives a higher chance of compliance with standard certified motorcycle helmet usage. 相似文献
570.