全文获取类型
收费全文 | 4450篇 |
免费 | 88篇 |
国内免费 | 317篇 |
专业分类
安全科学 | 196篇 |
废物处理 | 210篇 |
环保管理 | 475篇 |
综合类 | 946篇 |
基础理论 | 1295篇 |
污染及防治 | 1167篇 |
评价与监测 | 292篇 |
社会与环境 | 246篇 |
灾害及防治 | 28篇 |
出版年
2024年 | 5篇 |
2023年 | 31篇 |
2022年 | 72篇 |
2021年 | 63篇 |
2020年 | 47篇 |
2019年 | 35篇 |
2018年 | 154篇 |
2017年 | 180篇 |
2016年 | 230篇 |
2015年 | 109篇 |
2014年 | 96篇 |
2013年 | 190篇 |
2012年 | 529篇 |
2011年 | 335篇 |
2010年 | 119篇 |
2009年 | 111篇 |
2008年 | 150篇 |
2007年 | 166篇 |
2006年 | 152篇 |
2005年 | 468篇 |
2004年 | 589篇 |
2003年 | 460篇 |
2002年 | 107篇 |
2001年 | 122篇 |
2000年 | 66篇 |
1999年 | 67篇 |
1998年 | 17篇 |
1997年 | 33篇 |
1996年 | 13篇 |
1995年 | 23篇 |
1994年 | 15篇 |
1993年 | 8篇 |
1992年 | 14篇 |
1991年 | 20篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1979年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1966年 | 2篇 |
1957年 | 1篇 |
排序方式: 共有4855条查询结果,搜索用时 109 毫秒
981.
Kuo-Shuh Fan Tien Chin Chang Shih-Piao Ni Ching-Hwa Lee 《Waste management & research》2005,23(6):505-513
Mixed metal-containing waste, polychlorinated biphenyls (PCB) containing capacitors, printed circuit boards, steel mill dust and metal sludge were among the most common wastes exported from Taiwan. Before the implementation of the self-monitoring model programme of the Basel Convention (secretariat of the Basel Convention 2001) in the Asia region, Taiwan conducted a comprehensive 4-year follow-up project involving government authorities and the waste disposal facilities of the importing countries. A total of five countries and nine plants were visited in 2001-2002. The following outcomes can be drawn from these investigations. The Chinese government adopts the strategies of 'on-site processing' and 'relative centralization' on the waste management by tightening permitting and increasing site inspection. A three-level reviewing system is adopted for the import application. The United States have not signed the Basel Convention yet; the procedures of hazardous waste import rely on bilateral agreements. Importers are not required to provide official notification from the waste exporting countries. The operation, administration, monitoring and licensing of waste treatment plants are governed by the state environmental bureau. Finland, France and Belgium are members of the European Union. The procedures and policies of waste import are similar. All of the documents associated with transboundary movement require the approval of each government involved. Practically, the notification forms and tracking forms effectively manage the waste movement. 相似文献
982.
983.
Environmental fungi become a potential Indoor Air Quality (IAQ) problem when adequate moisture and nutrients are present in building materials. Because of their potential to rapidly spread contamination throughout a building, ventilation system materials are of particular significance as potential microbial contamination sources. Current recommendations are to discard fibrous glass insulation that appears to be wet or moldy. Unfortunately, this advice is not always followed. Instead, cleaning is sometimes being used in buildings to remediate fibrous glass duct liner that is already contaminated with microbial growth. The objectives of this research program were to: 1) determine, under dynamic test conditions, whether fungal spore levels on heating, ventilating, and air-conditioning (HVAC) duct material surfaces could be substantially reduced by thorough vacuum cleaning, 2) evaluate whether subsequent fungal growth could be limited or contained by mechanical cleaning, and 3) provide data concerning the advisability of cleaning duct materials. The constant high relative humidity (RH) environment to which the test materials were exposed during this study was selected as a favorable growth environment that is frequently found in Southeastern United States HVAC systems. The results showed that, following cleaning, the levels of the two test fungi, A. versicolor and P. chrysogenum, recovered to preclean levels within 6 weeks. Therefore, mechanical cleaning by contact vacuuming alone was able to only temporarily reduce the surface fungal load. The current guidelines to discard contaminated materials should be followed. 相似文献
984.
The expected impact of the “Peace Conduit” project (the Red Sea - Dead Sea pipeline) on the Dead Sea
Ittai?GavrieliEmail author Amos?Bein Aharon?Oren 《Mitigation and Adaptation Strategies for Global Change》2005,10(4):759-777
The Dead Sea is a severely disturbed ecosystem, greatly damaged by anthropogenic intervention in its water balance. During
the 20th century, the Dead Sea level dropped by more than 25 meters, and presently (2003) it is at about 416 meters below
mean sea level. This negative water balance is mainly due to the diversion of water from the catchment area of the lake by
Israel, Jordan and Syria. During the 2002 World Summit on Sustainable Development Israel and Jordan jointly announced their
interest in saving the Dead Sea by constructing the “Peace Conduit” that will pipe water from the Red Sea to the Dead Sea.
The inflow of seawater (or reject brine after desalinization) into the Dead Sea will have a major impact on its limnology,
geochemistry and biology. During the filling stage, relatively diluted surface water will form and the rate of evaporation
will therefore increase. Dilution of the surface water will most likely result in microbial blooming whose duration is not
known, while the lower water layer is likely to develop reducing conditions, including bacterial sulfate reduction and presence
of hydrogen sulfide (H2S). Mixing between the calcium-rich Dead Sea brine and the sulfate-rich seawater will result in gypsum precipitation (CaSO4⋅ 2H2O). Once the target level is reached, inflow will be outbalanced by evaporation and salinity of the surface water will increase
due to accumulation of seawater-salts. The water column will re-mix when the density of the surface water will equal that
of the lower water column. In spite of its large volume and high salinity relative to that of the inflowing water, over the
long run the composition of this unique lake will change. Before a decision is made on the planning and construction of the
Conduit, it is essential that the long term evolution and characteristics of the “renewed” Dead Sea be known and anticipated
changes examined. Once decided upon, the planning and construction of the Conduit should be conducted so as to minimize possible
negative impacts of seawater introduction on the Dead Sea. This can only be achieved through a thorough understanding of the
expected changes in the limnological physical/chemical characteristics of the Dead Sea and its unique brine. 相似文献
985.
Ernst Mayr: the doyen of twentieth century evolutionary biology 总被引:1,自引:0,他引:1
Hölldobler B 《Die Naturwissenschaften》2004,91(6):249-254
986.
987.
988.
Al/Si configurations in some natural and synthetic Rb-feldspars have been examined carefully by EMPA and XPS analyses. Our results indicate that a small amount of H2O and excess Si and Al are incorporated in hydrothermally synthesized Rb-feldspar. The quantities of excess Al are 0.056 atoms per formula unit and are negatively correlated with those of the Rb, suggesting the presence of excess Al occupying non-tetrahedral sites in feldspar structures. This leads to incorporation of Al(Al3Si)O8 endmember into Rb-feldspars, estimated as one appropriate endmember indication for unusual chemistry of feldspars. In addition, Si2p, Al2p and O1s XPS signals of Rb-feldspars shift drastically toward the higher energy side than those of any natural feldspars. These provide conclusive evidence not only for existence of perceptible excess Si and Al, but also for Al at both extra-framework and tetrahedral sites in feldspar structures. 相似文献
989.
The mechanism of caste differentiation in a social aphid Tuberaphis styraci, which has a sterile soldier caste in the 2nd instar, was investigated using an artificial diet rearing system. High aphid density induced soldier production. Combinatorial prenatal and postnatal density treatments revealed that (1) either prenatal high density or postnatal high density is sufficient for soldier induction; (2) thus, embryos in the maternal body and newborn 1st instar nymphs are both responsive to high density; (3) the combination of prenatal high density and postnatal high density enhances soldier differentiation in a synergistic manner; and (4) the final determination of soldier differentiation occurs postnatally, probably at a late 1st instar stage. This study first throws light on the developmental aspects of caste differentiation in a social aphid. 相似文献
990.
Food sharing among unrelated same-sex individuals has received considerable interest from primatologists and evolutionary biologists because of its apparent altruistic nature and implications for the evolution of complex social cognition. In contrast to primates, food sharing in birds has received relatively little attention. Here we describe three types of food sharing in jackdaws, with the initiative for the transfer either with the receiver or the giver. The latter situation is of particular interest because the food transfer takes place through active giving. Compared to primates, jackdaws show high rates of food sharing. Finally we discuss the implications of food sharing in jackdaws, and in birds in general. 相似文献