全文获取类型
收费全文 | 132篇 |
免费 | 8篇 |
专业分类
电工技术 | 4篇 |
综合类 | 4篇 |
化学工业 | 6篇 |
金属工艺 | 1篇 |
机械仪表 | 16篇 |
建筑科学 | 20篇 |
矿业工程 | 1篇 |
能源动力 | 21篇 |
轻工业 | 19篇 |
水利工程 | 19篇 |
石油天然气 | 6篇 |
无线电 | 1篇 |
一般工业技术 | 9篇 |
冶金工业 | 5篇 |
自动化技术 | 8篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 3篇 |
2020年 | 13篇 |
2019年 | 10篇 |
2018年 | 15篇 |
2017年 | 9篇 |
2016年 | 11篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 7篇 |
2012年 | 5篇 |
2011年 | 4篇 |
2010年 | 8篇 |
2008年 | 3篇 |
2007年 | 7篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有140条查询结果,搜索用时 15 毫秒
1.
Pakistan's bedwear industry contributes significantly to Pakistan's industry in general and to its textile industrial output and exports in particular. The exports of bedwear have increased steadily. However, its key basis of competitive advantage has been low cost. After greater liberalization from 2005 onwards and due to tariffication of quotas, the bedwear industry will not only have to scale higher tariff walls but will be more exposed to the threat of anti-dumping duties as it relies primarily on low prices to penetrate the export markets. To enhance its competitiveness, it will have to combine better quality with low costs and quick response. Research in quality management in Pakistan's bedwear industry was, therefore, undertaken. A postal self-completion questionnaire was mailed to 38 members of Pakistan Bedwear Manufacturers' and Exporters' Association (PBMEA). The response rate was almost 79%. It was found that this industrial segment was in various stages of development. This study demonstrates both the effectiveness and the limits of quality assurance in improving the levels of quality which remain a moving target in a dynamic liberalizing international trade environment that is more competitive since 2005. The bedwear industry, therefore, needs to graduate to advanced practices in quality management in order to remain competitive in rapidly changing times. 相似文献
2.
随着市场经济的快速发展,越来越多的中国企业到海外开拓市场。但由于工程建设周期长,受当地政策、自然灾害、物价上涨等不确定因素的影响,工程成本会发生变化,承包商为维护自身权益,必然会依据合同提出索赔,因而索赔工作尤为重要。对巴基斯坦阿莱瓦水电站在土建与金结合同执行全过程中,遭遇的所有干扰事件进行了描述,并对索赔依据、索赔计算和索赔金额进行了全面介绍,提供了一个完整的在严重受干扰项目中成功进行全过程索赔的典型案例。索赔经验可为类似工程提供参考。 相似文献
3.
关煜颖 《湖南工业职业技术学院学报》2014,(6):46-50
巴基斯坦作为当代与中国关系较为亲密稳固的国家之一,同时亦有着"宗教国家"与"美国旧盟友"的双重身份。从两极格局时的紧张对立到新世纪的紧密合作,中巴关系在国家利益与友谊的牵引下不断摸索着、发展着、巩固着。巴基斯坦作为宗教大国,对我们而言探究中巴关系变迁可以为当代中国进一步拓展与伊斯兰国家的关系找到突破口,加快与这些国家交往的步伐;同时,它对提高中国在伊斯兰国家的影响力也是有重大意义的,具有研究价值。 相似文献
4.
5.
Pollen morphology of 11 species of family Fabaceae that is, Trifolium alexandrinum, Trifolium resupinatum, Arachis hypogaea, Lathyrus aphaca, Medicago lupulina, Vicia sativa, Lathyrus odoratus, Pongamia pinnata, Melilotus indicus, Medicago polymorpha, Medicago sativa from Pakistan has been investigated by light and scanning electron microscopy. Pollen were generally tricolporate, radially symmetrical, isopolar, elliptic in equatorial view and triangular in polar view under LM. Results showed that pollens were per‐prolate (T. alexandrinum), prolate (T. resupinatum, V. sativa, L. odoratus, Melilotus indicus, M. polymorpha, M. sativa) and sub‐prolate (A. hypogaea, L. aphaca, M. lupulina, P. pinnata). The larger polar/equatorial (P/E) ratio was found in T. alexandrinum (2.26 μm) and the smallest was found in M. lupulina (1.21 μm). The exine of T. resupinatum was 3.00 μm in thickness while others posses smaller exine thickness. The larger pore diameter was found in P. pinnata (16.01 μm) while others have smaller. The length of colpi was larger in Arachis hypogaea (32.24) while others posses smaller. Eight types of surface ornamentation (Psilate, faintly rugulate). Perforate and rugulate to verrucate have been observed under SEM. The pollens were europalynous type. Pollen morphology proved to be useful for the specific delimitation and serve as a tool for the identification and classification of taxa at specific and generic levels and can also be used as a key for the taxonomic features. Diversity in exine sculpture is helpful indicative characters for the isolation of closely related species. Hence, it is clear that both qualitative and quantitative characters of pollen can be useful for differentiating between taxa at specific level. 相似文献
6.
Palyno‐morphological characteristics of gymnosperm flora of pakistan and its taxonomic implications with LM and SEM methods 下载免费PDF全文
Raees Khan Sheikh Zain Ul Abidin Mushtaq Ahmad Muhammad Zafar Jie Liu Hafiza Amina 《Microscopy research and technique》2018,81(1):74-87
The present study is intended to assess gymnosperms pollen flora of Pakistan using Light Microscope (LM) and Scanning Electron Microscopy (SEM) for its taxonomic significance in identification of gymnosperms. Pollens of 35 gymnosperm species (12 genera and five families) were collected from its various distributional sites of gymnosperms in Pakistan. LM and SEM were used to investigate different palyno‐morphological characteristics. Five pollen types (i.e., Inaperturate, Monolete, Monoporate, Vesiculate‐bisaccate and Polyplicate) were observed. Six In equatorial view seven types of pollens were observed, in which ten species were sub‐angular, nine species were Traingular, six species were Perprolate, three species were Rhomboidal, three species were semi‐angular, two species were rectangular and two species were prolate. While five types of pollen were observed in polar view, in which ten species were Spheroidal, nine species were Angular, eight were Interlobate, six species were Circular, two species were Elliptic. Eighteen species has rugulate and 17 species has faveolate ornamentation. Eighteen species has verrucate and 17 have gemmate type sculpturing. The data was analysed through cluster analysis. The study showed that these palyno‐morphological features have significance value in classification and identification of gymnosperms. Based on these different palyno‐morphological features, a taxonomic key was proposed for the accurate and fast identifications of gymnosperms from Pakistan. 相似文献
7.
Intizar Hussain Muhammad Mudasser Munir A. Hanjra Upali Amrasinghe David Molden 《国际水》2013,38(2):189-200
Abstract Increasing water scarcity, degradation of land and water resources, continuing low agricultural productivity, and increasing populations are posing the largest ever challenges for development of agricultural economies in many developing countries including Pakistan. Using panel data from irrigated settings in Chaj sub-basin of the Indus basin in Pakistani Punjab, we attempt to: (a) analyze the causes of low productivity; (b) disentangle factors (both land, water and other factors) contributing to productivity variations; and (c) identify limits and opportunities for narrowing productivity gaps and increasing overall wheat production, with a view to enhance food security for the poor. The results of the study indicate that locational inequities in distribution of canal water, use of groundwater of varying quality, differences in use of seed varieties, and other inputs lead to significant variations in wheat productivity. Key implications are that large gains in wheat productivity are possible by (a) improving the production environment at the tail-end through integrated water management practices; (b) adjusting the mix of canal and groundwater use; and (c) using technological interventions to improve the adoption of modern wheat varieties and dissemination of knowledge on planting dates and timings and application rates of inputs, especially water and fertilizer. Not only such interventions are economically, financially, and environmentally desirable, they are also pro-poor. What is needed is a strong political will and commitment. 相似文献
8.
Javaid Akhtar Muhammad Imran Yaqub Javed Iqbal Naseer Sheikh Tanzila Saba 《国际自然能源杂志》2018,39(8):904-908
In this review the energy potential of Pakistan from hydro, coal, wind, solar and nuclear sources has been discussed. The new projects that are being commissioned on coal, wind, solar, hydel and nuclear-based technologies have also been mentioned. The review has also explored the future prospects of the country’s energy requirements. Pakistan has potential to produce 100,000?MW of electricity from Thar coal for 20 years, 56,000?MW of hydroelectricity, 150,000?MW of wind energy and ~50,000?MW from solar sources. The coal-fired power generation is expected to 11,500?MW in period 2017–2019. The country is moving in the right direction to cater its energy needs. However, there is a need to find local and foreign investment in the country to meet high energy demands in the country in future. 相似文献
9.
Erika von Schneidemesser Tauseef A. Quraishi James J. Schauer 《The Science of the total environment》2010,408(7):1640-1648
Aerosol mass (PM10 and PM2.5) and detailed elemental composition were measured in monthly composites during the calendar year of 2007 at a site in Lahore, Pakistan. Elemental analysis revealed extremely high concentrations of Pb (4.4 μg m− 3), Zn (12 μg m− 3), Cd (0.077 μg m− 3), and several other toxic metals. A significant fraction of the concentration of Pb (84%), Zn (98%), and Cd (90%) was contained in the fine particulate fraction (PM2.5 and smaller); in addition, Zn and Cd were largely (≥ 60%) water soluble. The 2007 annual average PM10 mass concentration was 340 μg m− 3, which is well above the WHO guideline of 20 μg m− 3. Dust sources were found to contribute on average (maximum) 41% (70%) of PM10 mass and 14% (29%) of PM2.5 mass on a monthly basis. Seasonally, concentrations were found to be lowest during the monsoon season (July-September). Principle component analysis identified seven factors, which combined explained 91% of the variance of the measured components of PM10. These factors included three industrial sources, re-suspended soil, mobile sources, and two regional secondary aerosol sources likely from coal and/or biomass burning. The majority of the Pb was found to be associated with one industrial source, along with a number of other toxic metals including As and Cr. Cadmium, another toxic metal, was found at concentrations 16 times higher than the maximum exposure level recommended by the World Health Organization, and was concentrated in one industrial source that was also associated with Zn. These results highlight the importance of focusing control strategies not only on reducing PM mass concentration, but also on the reduction of toxic components of the PM as well, to most effectively protect human health and the environment. 相似文献
10.
针对Naltar河道推移质对取水方式的影响,通过比较常规闸坝,结合引水方式的优缺点,在巴基斯坦北部地区首次应用了底栏栅坝式取水型式,实践证明该引水方式是成功的。同时提出了底栏栅坝应用于山区多泥沙河流设计中应注意的问题。 相似文献