全文获取类型
收费全文 | 366篇 |
免费 | 16篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 28篇 |
废物处理 | 18篇 |
环保管理 | 76篇 |
综合类 | 67篇 |
基础理论 | 73篇 |
环境理论 | 3篇 |
污染及防治 | 79篇 |
评价与监测 | 19篇 |
社会与环境 | 13篇 |
灾害及防治 | 10篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 13篇 |
2017年 | 15篇 |
2016年 | 19篇 |
2015年 | 9篇 |
2014年 | 10篇 |
2013年 | 28篇 |
2012年 | 18篇 |
2011年 | 18篇 |
2010年 | 22篇 |
2009年 | 18篇 |
2008年 | 22篇 |
2007年 | 20篇 |
2006年 | 18篇 |
2005年 | 14篇 |
2004年 | 9篇 |
2003年 | 10篇 |
2002年 | 12篇 |
2001年 | 2篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1964年 | 1篇 |
1925年 | 1篇 |
1915年 | 1篇 |
1914年 | 1篇 |
排序方式: 共有386条查询结果,搜索用时 15 毫秒
101.
Aaron Barkoh Dennis G. Smith Gregory M. Southard 《Journal of the American Water Resources Association》2010,46(1):161-169
Barkoh, Aaron, Dennis G. Smith, and Gregory M. Southard, 2010. Prymnesium parvum Control Treatments for Fish Hatcheries. Journal of the American Water Resources Association (JAWRA) 46(1):161-169. DOI: 10.1111/j.1752-1688.2009.00400.x Abstract: In 2001, the ichthyotoxic microalga Prymnesium parvum caused massive fish kills and adversely affected fish production at the Texas Parks and Wildlife Department (TPWD) Dundee State Fish Hatchery. Since then, we have investigated several P. parvum bloom and ichthyotoxicity control treatments to develop management strategies that allow fish production and prevent the spread of the alga into unaffected hatcheries and impoundments. Current control successes include treatments for ponds, water supply, and a hazard analysis and critical control point program. For pond treatment, ammonium sulfate (as 0.14-0.25 mg/l un-ionized ammonia nitrogen for temperatures above 15°C), copper sulfate (2 mg/l), Cutrine®-Plus (0.2-0.4 mg/l as copper), or potassium permanganate (3 mg/l above the potassium permanganate demand) controls P. parvum blooms. Copper sulfate at 1 mg/l controls P. parvum but is unable to eliminate ichthyotoxicity whereas potassium permanganate at 2 mg/l above the potassium permanganate demand controls ichthyotoxicity. For water treatment, ultraviolet (UV) light at 193-220 mJ/cm2 doses or ozone at 0.4-1.2 mg/l for 6 min destroy P. parvum cells and reduce or eliminate ichthyotoxicity. A combination UV and ozone treatment appears to provide the best results; however, successful treatments depend on dosage relative to cell density and toxin concentration. To prevent the spread of the alga, hatchery fish delivery units and equipment are cleaned with household bleach (10% solution for 15 minutes) or hydrogen peroxide (62.5-12,500 mg/l for 0.25-24 hours). These treatments are tailored to water quality conditions and the fish species cultured at affected TPWD hatcheries. We recommend that other users test these treatments before applying them to ponds or other impoundments containing fish or other aquatic life. 相似文献
102.
Gas-phase atmospheric deposition wasevaluated in a screening level model of themultimedia environmental distribution of toxics(MEND-TOX). Algorithmic additions to MEND-TOXfor the estimation of gas-phase depositionvelocity over vegetated surfaces were analyzedusing recently published dry deposition fluxmeasurements for nitric acid. Model outputs arecompared to similar estimates from the NOAAmultilayer dry deposition model. Results of theevaluation indicate that MEND-TOX performs wellas a screening level model for the estimation ofgas-phase dry deposition velocity of nitric acidover soybeans. The present study expandsprevious laboratory results for organic speciesto include an inorganic species and open fieldand dry leaf, conditions.(On assignment to the National Exposure Research Laboratory, U.S. Environmental Protection Agency); (author for correspondence, e-mail 相似文献
103.
104.
105.
Sharon L. Forbes David A. Cohen Ross Cullen Stephen D. Wratten Joanna Fountain 《Journal of Cleaner Production》2009,17(13):1195-1199
Previous research has suggested that consumers are becoming increasingly concerned by the effects of conventional agricultural food production practices on human health and environmental wellbeing. This study sought to understand whether environmentally sustainable practices in the vineyard would equate to advantages in the wine marketplace. Structured questionnaires were used to ascertain the views of wine consumers in Christchurch, New Zealand. The findings of this study indicate that consumers have a strong demand for wine which is produced using “green” production practices. Consumers believe that the quality of sustainable wine will be equal to or better than conventionally produced wine, and they are prepared to pay a higher price for this wine. 相似文献
106.
107.
Arctic cod (Boreogadus saida) is a schooling fish providing a critical link between lower and upper trophic levels in the Arctic. This study examined foraging of Arctic cod collected from Allen Bay, Cornwallis Island, Canada (~75 N 95 W), during summer 2010 using temporal indicators of diet including stomach content, and carbon (δ13C) and nitrogen (δ15N) stable isotopes of liver and muscle. Foraging at the time of capture reflected sympagic and epi-benthic habitats indicated by the prevalence of cyclopoid and harpacticoid copepods in stomachs, whereas stable isotope data, which provide an estimate of feeding over a longer period, indicated pelagic prey as important. Prey selection of juveniles differed from adults based on stable isotopes, while large adults showed the most separation based on stomach contents, suggesting size-related diet shifts. Compared to studies near Resolute in the 1970s, 1980s, and 1990s, growth and pre-spawning gonadal conditions of Arctic cod have not changed. 相似文献
108.
Recent histological studies have revealed a diversity of dental features in Permo-Carboniferous tetrapods. Here, we report on the occurrence of plicidentine (infolded dentine around the base of the tooth root) in Sphenacodontia, the first such documentation in Synapsida, the clade that includes mammals. Five taxa were examined histologically, Ianthodon schultzei, Sphenacodon ferocior, Dimetrodon limbatus, Dimetrodon grandis, and Secodontosaurus obtusidens. The tooth roots of Ianthodon possess multiple folds, which is generally viewed as the primitive condition for amniotes. Sphenacodon and D. limbatus have distinctive “four-leaf clover”-shaped roots in cross section, whereas Secodontosaurus has an elongate square shape with only subtle folding. The most derived and largest taxon examined in this study, D. grandis, has rounded roots in cross section and therefore no plicidentine. This pattern of a loss of plicidentine in sphenacodontids supports previous functional hypotheses of plicidentine, where teeth with shallow roots require folds to increase the area of attachment to the tooth-bearing element, whereas teeth with long roots do not. This pattern may also reflect differences in diet between co-occurring sphenacodontids as well as changes in feeding niche through time, specifically in the apex predator Dimetrodon. 相似文献
109.
Glenn EP Flessa KW Cohen MJ Nagler PL Rowell K Zamora-Arroyo F 《Environmental management》2007,40(1):1-6
A recent article in Environmental Management by All argued that flood flows in North America’s Colorado River do not reach the Gulf of California because they are captured
and evaporated in Laguna Salada, a below sea-level lakebed near the mouth of the river. We refute this hypothesis by showing
that (1) due to its limited area, the Laguna Salada could have evaporated less than 10% of the flood flows that have occurred
since 1989; (2) low flow volumes preferentially flow to the Gulf rather than Laguna Salada; (3) All’s method for detecting
water surface area in the Laguna Salada appears to be flawed because Landsat Thematic Mapper images of the lakebed show it
to be dry when All’s analyses said it was flooded; (4) direct measurements of salinity at the mouth of the river and in the
Upper Gulf of California during flood flows in 1993 and 1998 confirm that flood waters reach the sea; and (5) stable oxygen
isotope signatures in clam shells and fish otoliths recorded the dilution of seawater with fresh water during the 1993 and
1998 flows. Furthermore, All’s conclusion that freshwater flows do not benefit the ecology of the marine zone is incorrect
because the peer-reviewed literature shows that postlarval larval shrimp populations increase during floods, and the subsequent
year’s shrimp harvest increases. Furthermore, freshwater flows increase the nursery area for Gulf corvina (Cynoscion othonopterus), an important commercial fish that requires estuarine habitats with salinities in the range of 26–38‰ during its natal stages.
Although flood flows are now much diminished compared to the pre-dam era, they are still important to the remnant wetland
and riparian habitats of the Colorado River delta and to organisms in the intertidal and marine zone. Only a small fraction
of the flood flows are evaporated in Laguna Salada. 相似文献
110.
Use of isotopic analysis of vertebrae in reconstructing ontogenetic feeding ecology in white sharks 总被引:2,自引:0,他引:2
We conducted stable 13C and 15N analysis on white shark vertebrae and demonstrated that incremental analysis of isotopes along the radius of a vertebral centrum produces a chronological record of dietary information, allowing for reconstruction of an individual's trophic history. Isotopic data showed significant enrichments in 15N with increasing sampling distance from the centrum center, indicating a correlation between body size and trophic level. Additionally, isotopic values verified two distinct ontogenetic trophic shifts in the white shark: one following parturition, marking a dietary switch from yolk to fish; and one at a total length of >341 cm, representing a known diet shift from fish to marine mammals. Retrospective trophic-level reconstruction using vertebral tissue will have broad applications in future studies on the ecology of threatened, endangered, or extinct species to determine life-long feeding patterns, which would be impossible through other methods. 相似文献