全文获取类型
收费全文 | 293篇 |
免费 | 9篇 |
国内免费 | 23篇 |
专业分类
安全科学 | 74篇 |
废物处理 | 6篇 |
环保管理 | 59篇 |
综合类 | 86篇 |
基础理论 | 55篇 |
污染及防治 | 10篇 |
评价与监测 | 10篇 |
社会与环境 | 6篇 |
灾害及防治 | 19篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 6篇 |
2020年 | 7篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 8篇 |
2013年 | 20篇 |
2012年 | 4篇 |
2011年 | 16篇 |
2010年 | 8篇 |
2009年 | 16篇 |
2008年 | 9篇 |
2007年 | 16篇 |
2006年 | 20篇 |
2005年 | 17篇 |
2004年 | 11篇 |
2003年 | 20篇 |
2002年 | 18篇 |
2001年 | 15篇 |
2000年 | 13篇 |
1999年 | 10篇 |
1998年 | 3篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 7篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1972年 | 4篇 |
1971年 | 4篇 |
1970年 | 2篇 |
排序方式: 共有325条查询结果,搜索用时 203 毫秒
71.
72.
73.
Summary. Allopatric populations of the leaf beetle Chrysomela lapponica are known to feed upon either willow (Salicaceae) or birch (Betulaceae). This study aimed to elucidate the differentiation
process of these allopatric populations. We investigated whether these allopatric populations specialized on different host
plants are still able to produce fertile offspring when interbreeding. Individuals from a population in Finland (willow specialists)
and one in the Czech Republic (birch specialists) were crossed in laboratory. Hybrid formation succeeded only between females
from the Czech, birch specialized population and males from the Finnish, willow specialized population, while no eggs were
produced by females of the willow specialists having mated males of the birch specialists. Behavioral, morphological, physiological,
and chemical features of the F1 hybrids were studied. The chemical composition of larval defensive secretion and feeding preferences of the resulting F1 hybrids mainly showed similarities with the paternal phenotype, while the area of black coloring on the offspring’s elytra
was intermediate between those of the parental elytra. F1 hybrids did not accept the host plant (birch) of their mothers for feeding and only survived on willow. Thus, since mothers
only lay eggs on birch, we found evidence for a postzygotic isolation mechanism between the individuals of the two investigated
populations: when having been mated with willow specialized Finnish males, the birch specialized Czech mothers place the hybrid
eggs on a plant species (birch), on which the hatching larvae cannot survive. 相似文献
74.
郭斌 《安全.健康和环境》2003,3(1):11-13
介绍了立式金属油罐容积编表计算机自动查询与计算系统的设计思想,查询计算原理,功能及实现,程序的编制及调试,应用及测试等,该系统的建立旨在克服人工查询与计算方法的计算繁琐,费时,易出差错的缺点,达到了本质安全。 相似文献
75.
公路建设项目环境影响评价软件RoadEIA介绍 总被引:2,自引:0,他引:2
介绍了公路建设项目环境影响评价软件RoadEIA的框架及软件各部分的功能,举了一个用该软件进行评价的工程实例,最后分析总结了该软件的特点。 相似文献
76.
散化码头化学品水污染危害性评估模式研究 总被引:3,自引:0,他引:3
提出散化码头三类典型液体化学品水污染危害性评估模式 ,并建立其计算扩散模型。 相似文献
77.
L.R. LITTLE R.Q. GRAFTON T. KOMPAS A.D.M. SMITH A.E. PUNT B.D. MAPSTONE 《Conservation biology》2011,25(2):333-340
Abstract: Changes in the management of the fin fish fishery of the Great Barrier Reef motivated us to investigate the combined effects on economic returns and fish biomass of no‐take areas and regulated total allowable catch allocated in the form of individual transferable quotas (such quotas apportion the total allowable catch as fishing rights and permits the buying and selling of these rights among fishers). We built a spatially explicit biological and economic model of the fishery to analyze the trade‐offs between maintaining given levels of fish biomass and the net financial returns from fishing under different management regimes. Results of the scenarios we modeled suggested that a decrease in total allowable catch at high levels of harvest either increased net returns or lowered them only slightly, but increased biomass by up to 10% for a wide range of reserve sizes and an increase in the reserve area from none to 16% did not greatly change net returns at any catch level. Thus, catch shares and no‐take reserves can be complementary and when these methods are used jointly they promote lower total allowable catches when harvest is relatively high and encourage larger no‐take areas when they are small. 相似文献
78.
Peter E. Black 《Journal of the American Water Resources Association》1980,16(5):894-899
ABSTRACT: A method, adapted to an APL interactive terminal, is described which allows the operator to thoroughly search a large set of gaged watersheds in order to find sources of comparable hydrologic data for detailed analysis. Bases of the search - and inventory - include drainage basin size and elevation, and geographical and temporal parameters, and should enhance opportunities for more reliable use of existing data. 相似文献
79.
Thomas M. Walski Anthony Pelliccia 《Journal of the American Water Resources Association》1981,17(1):49-56
ABSTRACT: In estimating the costs of a reservoir project, it is difficult to produce accurate costs without performing a detailed design and quantity takeoff. The computerized procedure presented in this article provides a method for determining these planning level costs quickly and easily, while maintaining reasonable accuracy. 相似文献
80.
Yeou-Koung Tung Larry W. Mays 《Journal of the American Water Resources Association》1981,17(2):181-189
ABSTRACT: A nonlinear hydrologic system model has been developed for analyzing the urban rainfall-runoff process. The model is formulated as a state variable model consisting of several parameters. A search technique is employed to find the set of parameters for which the model's response best fits observed data. The model could be used in either a simulation or forecasting mode. The model is applied to observed data for the Waller Creek Watershed in Austin, Texas, to develop the model parameters for various levels of urbanization of the watershed. The trend of each parameter with respect to levels of urbanization is examined. 相似文献