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81.
气候变化和人类活动对塔里木盆地绿洲演化的影响 总被引:17,自引:4,他引:13
通过对不同时间尺度下气候变化和人类活动对塔里木盆地绿洲形成与演化的影响分析。认为水文状况的变化是决定绿洲演化的首要因素,气候变化与人类活动也正是通过直接或间接地对绿洲水文状况产生影响而导致绿洲演化的。人类活动对绿洲演化的影响是局部的、阶段性的,而气候变化对绿洲演化的影响则是宏观的、连续性的。 相似文献
82.
A numerical experiment study for effects of the grassland desertification on summer drought in North China 总被引:2,自引:2,他引:0
1IntroductionDManyobservationsandstudiesindicatethatthesummerrainfallinNorthChinadecreasessignificantlyduringrecenttwentyyears.Theobviousreductiontendencycanbeseenfromthevariationofpercentageofsummerrainfallanomaly(June--August)intheplainofNorthChina... 相似文献
83.
吉林省西部荒漠化发展的陆地卫星遥感监测分析 总被引:25,自引:2,他引:23
依据1996年8~10月和1988年8~10月两个时期的LANDSATTM遥感信息静态反演,对两个时期TM资料采用图像增强处理和计算机监督分类进行荒漠化(侧重乾安县盐渍化)解译和动态量变分析,并与1976年和1981年的卫片进行对比分析,研究结果表明,吉林省西部的生态环境在恶化,主要表征为荒漠化发展并向东扩张,已波及吉林省中部松辽平原。大安县是吉林省盐渍化面积最多的县份,已占全县总面积的50%以上;乾安县是盐渍化面积漫延较快的县份,盐渍化面积8a增加了269.77km2,增加量占总面积的7.87%。 相似文献
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Many cosmic facts , such as the earth orbit, the activity of the sun, the moon and the planet orbits and so on,may effect on geological processes on the earth including precipitation. It is a serious problem that the human being is facing with water deficiency. Global cooling and tectonic activity are the major factors of desertification and human action aggravates this process. It is time to do something to prevent the acceleration in the mature and artificial hazards. We must keep the balance of nature for sustainable development. 相似文献
87.
Xiaoan Zuo Halin Zhao Xueyong Zhao Yirui Guo Jianying Yun Shaokun Wang Takafumi Miyasaka 《Environmental Geology》2009,58(6):1227-1237
The Horqin Sandy Land is one of the most severely desertified regions in northern China. Plant communities and soil conditions
at five stages of grassland desertification (potential, light, moderate, severe and very severe) were selected for the study
of vegetation pattern variation relating to soil degradation. The results showed that vegetation cover, species richness and
diversity, aboveground biomass (AGB), underground biomass, litter, soil organic carbon (C), total nitrogen (N), total phosphorus
(P), electrical conductivity, very fine sand (0.1–0.05 mm) content and silt (0.05–0.002 mm) content decreased with the desertification
development. Plant community succession presented that the palatable herbaceous plants gave place to the shrub species with
asexual reproduction and sand pioneer plants. The decline of vegetation cover and AGB was positively related to the loss of
soil organic C and total N with progressive desertification (P < 0.01). The multivariate statistical analysis showed that plant community distribution, species diversity and ecological
dominance had the close relationship with the gradient of soil nutrients in the processes of grassland desertification. These
results suggest that grassland desertification results in the variation of vegetation pattern which presents the different
composition and structure of plant community highly influenced by the soil properties. 相似文献
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T. Miyasaka T. OkuroH. Zhao X. ZhaoX. Zuo K. Takeuchi 《Journal of Arid Environments》2011,75(11):1155-1163
We examined changes in soil properties, crop biomass, and weed communities in the Horqin Sandy Land of China to elucidate cropland degradation. We studied three local cropland types having periods of cultivation of up to 20 years: maize cropland on lowlands without irrigation (nonirrigated lowland), maize cropland on flat sandy lands with irrigation (irrigated flatland), and bean-centered cropland on sand dunes without irrigation (nonirrigated dunes). Soil properties and crop biomass were more degraded in nonirrigated lowland and nonirrigated dunes than in irrigated flatland. Weed communities in the nonirrigated croplands were the type that become established in drier conditions, whereas wetland weeds were more abundant on irrigated flatland. Trends of change in each indicator did not always occur in parallel and differed statistically among the cropland types. Monitoring these indicators within the context of local land-use systems can provide scientific evidence on which to base local management practices or recommendations for change. 相似文献
90.
《Climate Policy》2013,13(2-3):129-144
Abstract Climate change does not yet feature prominently within the environmental or economic policy agendas of developing countries. Yet evidence shows that some of the most adverse effects of climate change will be in developing countries, where populations are most vulnerable and least likely to easily adapt to climate change, and that climate change will affect the potential for development in these countries. Some synergies already exist between climate change policies and the sustainable development agenda in developing countries, such as energy efficiency, renewable energy, transport and sustainable land-use policies. Despite limited attention from policy-makers to date, climate change policies could have significant ancillary benefits for the local environment. The reverse is also true as local and national policies to address congestion, air quality, access to energy services and energy diversity may also limit GHG emissions. Nevertheless there could be significant trade-offs associated with deeper levels of mitigation in some countries, for example where developing countries are dependent on indigenous coal and may be required to switch to cleaner yet more expensive fuels to limit emissions. The distributional impacts of such policies are an important determinant of their feasibility and need to be considered up-front. It follows that future agreements on mitigation and adaptation under the convention will need to recognise the diverse situations of developing countries with respect to their level of economic development, their vulnerability to climate change and their ability to adapt or mitigate. Recognition of how climate change is likely to influence other development priorities may be a first step toward building cost-effective strategies and integrated, institutional capacity in developing countries to respond to climate change. Opportunities may also exist in developing countries to use regional economic organisations to assist in the design of integrated responses and to exploit synergies between climate change and other policies such as those designed to combat desertification and preserve biodiversity. © 2002 Elsevier Science Ltd. All rights reserved. 相似文献