全文获取类型
收费全文 | 1804篇 |
免费 | 28篇 |
国内免费 | 15篇 |
专业分类
安全科学 | 53篇 |
废物处理 | 67篇 |
环保管理 | 298篇 |
综合类 | 303篇 |
基础理论 | 431篇 |
环境理论 | 4篇 |
污染及防治 | 469篇 |
评价与监测 | 134篇 |
社会与环境 | 83篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 19篇 |
2022年 | 20篇 |
2021年 | 25篇 |
2020年 | 24篇 |
2019年 | 23篇 |
2018年 | 39篇 |
2017年 | 47篇 |
2016年 | 43篇 |
2015年 | 46篇 |
2014年 | 50篇 |
2013年 | 127篇 |
2012年 | 73篇 |
2011年 | 108篇 |
2010年 | 77篇 |
2009年 | 92篇 |
2008年 | 95篇 |
2007年 | 115篇 |
2006年 | 84篇 |
2005年 | 73篇 |
2004年 | 72篇 |
2003年 | 67篇 |
2002年 | 78篇 |
2001年 | 33篇 |
2000年 | 26篇 |
1999年 | 18篇 |
1998年 | 19篇 |
1997年 | 23篇 |
1996年 | 18篇 |
1995年 | 23篇 |
1994年 | 25篇 |
1993年 | 13篇 |
1992年 | 16篇 |
1991年 | 15篇 |
1990年 | 12篇 |
1989年 | 12篇 |
1988年 | 17篇 |
1987年 | 12篇 |
1986年 | 15篇 |
1984年 | 8篇 |
1983年 | 10篇 |
1982年 | 11篇 |
1981年 | 9篇 |
1980年 | 7篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1974年 | 6篇 |
1955年 | 5篇 |
1954年 | 8篇 |
排序方式: 共有1847条查询结果,搜索用时 296 毫秒
831.
832.
Martin Paulus Monika Altmeyer Roland Klein Armin Hildebrandt Peter Ostapczuk Konstantin Oxynos 《Umweltwissenschaften und Schadstoff-Forschung》1994,6(6):375-383
Ein sinnvoller Einsatz von Akkumulationsindikatoren erfordert zur Qualit?tssicherung neben den vorhandenen Laborstandards
ein anspruchsvolles Probenahmeverfahren, um repr?sentative und reproduzierbate Aussagen über einen Untersuchungsraum treffen
zu k?nnen. Am Beispiel der Regenwürmer wird exemplarisch ein Probenahmeverfahren für landwirtschaftliche R?ume entwickelt
und vorgeführt. Erste Ergebnisse der in den Wurm- und Kotproben gemessenen polyzyklischen aromatischen Kohlenwasserstoffe,
der chlorierten Kohlenwasserstoffe und der Elemente werden dargestellt. Die Schadstoffgehalte der vergleichbaren Wurmproben
belegen, da? es die repr?sentative Probenahmestelle in einem Untersuchungsgebiet nicht gibt. Die Heterogenit?t des Untersuchungsraumes
kann nur durch eine geschichtete Zufallsstichprobe mit einer ausreichenden Anzahl von Einzelproben erfa?t werden. 相似文献
833.
The use of principal components analysis for the quality control of a mass spectrometer is demonstrated and commented upon. 相似文献
834.
Transformation of effluent organic matter during subsurface wetland treatment in the Sonoran Desert 总被引:6,自引:0,他引:6
The fate of dissolved organic matter (DOM) during subsurface wetland treatment of wastewater effluent in a hot, semi-arid environment was examined. The study objectives were to (1) discern changes in the character of dissolved organics as consequence of wetland treatment (2) establish the nature of wetland-derived organic matter, and (3) investigate the impact of wetland treatment on the formation potential of trihalomethanes (THMs). Subsurface wetland treatment produced little change in DOM polarity (hydrophobic-hydrophilic) distribution. Biodegradation of labile effluent organic matter (EfOM) and internal loading of wetland-derived natural organic matter (NOM) together produced only minor changes in the distribution of carbon moieties in hydrophobic acid (HPO-A) and transphilic acid (TPI-A) isolates of wetland effluent. Aliphatic carbon decreased as a percentage of total carbon during wetland treatment. The ratio of atomic C:N in wetland-derived NOM suggests that its character is determined by microbial activity. Formation of THMs upon chlorination of HPO-A and TPI-A isolates increased as a consequence of wetland treatment. Wetland-derived NOM was more reactive in forming THMs and less biodegradable than EfOM. For both HPO-A and TPI-A fractions, relationships between biodegradability and THM formation potential were similar among EfOM and NOM isolates; the less biodegradable isolates exhibited greater THM formation potential. 相似文献
835.
The dynamics of male-male competition for mates and patterns of female choice depend critically on the social environment. We released newly molted sexually receptive females of the rock shrimp Rhynchocinetes typus in the field and recorded their interactions with males. In the dense aggregations in which these shrimp live, most females were encountered and seized by males within 2 min. Usually, females were first seized by subordinate males, and subsequently taken over by the dominant males. Many females (17 out of 23) had multiple mates during the 10-min observation period, and most of them received spermatophores from multiple males. Males used different mating tactics in accordance with their dominance status: subordinate males often used the sneaking tactic, seizing the female and immediately transferring spermatophores. In contrast, all dominant males used the primary mating tactic; they seized and stimulated the female before transferring spermatophores. Results from previous studies had indicated that females may reduce the fertilization chances of subordinate males by delaying spawning and removing spermatophores. We suggest that this capability in combination with the observed rapid mate succession may enable females to exploit male contest behaviors.Communicated by P. Backwell 相似文献
836.
837.
We describe the oldest tracks of web-footed birds from the Early Cretaceous in South Korea. The tracks are characterized
by a wide divarication angle and a long reversed hallux. The web is semipalmate and restricted to the proximal portion of
the three forward digits. The tracks from the Early Cretaceous in South Korea are smaller than those of the Late Cretaceous,
therefore confirming the trend of size increasing in the early evolution of birds as shown by skeletal fossils. The discovery
of web-footed tracks with abundant non-web-footed tracks indicates that there was a considerable diversification of shore
birds as early as the Early Cretaceous.
Received: 4 November 1999 / Accepted in revised form: 28 February 2000 相似文献
838.
Beth A. Pletcher Maureen M. Sanz Jerrold S. Schlessel Suphat Kunaporn Carrie McKenna Martin G. Bialer M. Lita Alonso Ann-Leslie Zaslav W. Ted Brown James H. Ray 《黑龙江环境通报》1994,14(10):933-940
Two phenotypically abnormal liveborns in whom trisomy 16 mosaicism was diagnosed prenatally by amniocentesis are described. Analysis of a percutaneous umbilical blood sample in one case revealed a normal chromosomal complement. Ultrasound examinations performed at the time of amniocentesis were normal. Serial sonography during the late second and third trimesters demonstrated progressive intrauterine growth retardation (IUGR) in both fetuses and a cardiac defect in one. At birth, both infants had dysmorphic features and multiple congenital anomalies. Trisomy 16 mosaicism was confirmed postnatally in both infants in skin fibroblasts; however, peripheral blood samples contained only chromosomally normal cells. The two mosaic trisomy 16 cases described in this report, together with the five confirmed cases reported previously, demonstrate the need for caution in the counselling of patients when trisomy 16 mosaicism is diagnosed prenatally in amniotic fluid samples. Such cases potentially can result in the birth of dysmorphic infants with significant birth defects, growth retardation, and possible developmental disabilities. 相似文献
839.
Eggs of sharp-shinned hawks (Accipiter striatus), Cooper's hawks (A. cooperii), and northern goshawks (A. gentilis) were collected from nests in south-central Ontario from 1986 to 1989. Detectable levels of the chlorinated hydrocarbons DDE, DDT, DDD, mirex, photomirex, cis-nonachlor, trans-nonachlor, oxychlordane, dieldrin, heptachlor expoxide, HCB and PCB were present in all the eggs analyzed. Mean contaminant levels were highest in sharp-shinned hawks, slightly lower in Cooper's hawks, and significantly lower in goshawks; for example, mean DDE values were 7.23, 4.48 and 0.90 mg kg(-1) (wet weight), respectively. Total PCB levels were generally less than 1.5 mg kg(-1), lower than those associated with reproductive effects in field and laboratory studies with other species. Mean shell thicknesses of sharp-shinned and Cooper's hawk eggs were significantly less than mean pre-DDT era thicknesses (-10 and -8%, respectively), reductions that were probably not relevant to reproductive success. Goshawk eggs exhibited no significant reduction in shell thickness. Contaminant levels among the three species probably reflect differing food habits and migratory patterns. 相似文献
840.
Martin Spray Caroline Saunders David Pearce Ian Thompson Patsy Healey 《Journal of Environmental Planning and Management》1994,37(1):117-122
Ecological Economics: The Science and Management of Sustainability
R. Costanza (Ed.)
New York, Columbia, 1991, 515 pp.
Environmental Auditing: The Challenge of the 1990s
Banff Centre for Management
Calgary, University of Calgary Press, 1992, 236 pp, pb.
Interpreting Nature: Cultural Constructions of the Environment
I. G. Simmons
London, Routledge, 1993, 200 pp., £40 hb, £12.99 pb 相似文献