全文获取类型
收费全文 | 408篇 |
免费 | 16篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 16篇 |
废物处理 | 5篇 |
环保管理 | 93篇 |
综合类 | 65篇 |
基础理论 | 115篇 |
污染及防治 | 89篇 |
评价与监测 | 14篇 |
社会与环境 | 19篇 |
灾害及防治 | 12篇 |
出版年
2023年 | 6篇 |
2022年 | 8篇 |
2021年 | 9篇 |
2020年 | 10篇 |
2019年 | 13篇 |
2018年 | 10篇 |
2017年 | 23篇 |
2016年 | 20篇 |
2015年 | 17篇 |
2014年 | 21篇 |
2013年 | 47篇 |
2012年 | 15篇 |
2011年 | 27篇 |
2010年 | 15篇 |
2009年 | 14篇 |
2008年 | 15篇 |
2007年 | 7篇 |
2006年 | 14篇 |
2005年 | 7篇 |
2004年 | 16篇 |
2003年 | 13篇 |
2002年 | 9篇 |
2001年 | 7篇 |
2000年 | 10篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1972年 | 3篇 |
1970年 | 2篇 |
1964年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有428条查询结果,搜索用时 703 毫秒
301.
Helen Rendell 《Environmental management》1985,9(4):289-301
In this study, the damage caused to one small hilltop town by the southern Italian earthquake of November 1980 is considered in detail. Tricarico, although peripheral to the epicenter zone, was gravely damaged. The distribution of damaged properties within the historic center of the town is described and analyzed. The geological and socioeconomic factors contributing to the pattern of damage are discussed and the problems associated with reconstruction are considered. 相似文献
302.
Helen Ingram 《Journal of the American Water Resources Association》1972,8(6):1177-1188
A set of decision rules have governed the traditional politics of water development. This paper identifies these rules, describes their operation, and explains the logic behind their adoption. Personal interviews with a large number of decision makers are cited to substantiate and illustrate particular rules. There are five decision rules: local support, agreement, mutual accommodation, mutual noninterference, and fairness and equity. These guidelines are intended to insure support, lessen conflict, and protect the reputation of water development as a worthwhile federal investment. Since there are current indications that the traditional decision rules are no longer followed, the paper aims to identify why and how the rules are changing. 相似文献
303.
The suggestion that the annual cycle of plant production in tropical oceanic regions may be negligible or non-existent is examined, using data from a year-long cruise series in the eastern tropical Pacific. Results of analysis of variance show a highly significant seasonal effect. Average values of the seasonal cycle were found to range from 127 to 318 mg C/m2/day, a systematic two-fold variation over the year. Annual production was 75 g C/m2/year. Significant differences also were found between longitudes, and a slightly significant interaction occurred between season and longitude. Probable sources of the seasonal cycle include time variation of thermocline topography and variation of nutrient supply from local source areas such as the Costa Rica Dome, Gulf of Tehuantepec, Peru Current extension, and Equatorial Undercurrent domain. 相似文献
304.
Matthew Gronquist Frank C. Schroeder Helen Ghiradella David Hill Erin M. McCoy Jerrold Meinwald Thomas Eisner 《Chemoecology》2006,16(1):39-43
Summary. Lucidota atra, a diurnal firefly, shares possession of defensive steroids (lucibufagins or LBGs) with nocturnal fireflies of the genus
Photinus. Photinus are protected against predators by their LBGs, but not against fireflies of the genus Photuris, the so-called firefly femmes fatales, which prey upon Photinus, thereby acquiring LBGs for their own defense. We propose that L. atra may have been prompted evolutionarily to become diurnal by the opportunity to avoid, thereby, being hunted by Photuris. Indeed, L. atra, if offered to Photuris, were eagerly devoured by the latter, which sequestered their LBG’s. In feeding on L. atra, Photuris may be driven by a gustatory affinity for LBGs. Persistent nocturnality might therefore have put L. atra at risk vis à vis Photuris. Diurnality freed the firefly from that risk, without compromising its defended status with respect to other predators. Possession
of LBGs may in fact account for L. atra’s unacceptability to birds and spiders. 相似文献
305.
Techniques and Guidelines for Monitoring Neotropical Butterflies 总被引:11,自引:0,他引:11
Helen R. Sparrow Thomas D. Sisk Paul R. Ehrlich Dennis D. Murphy 《Conservation biology》1994,8(3):800-809
Long-term monitoring of selected species can identify changes in biological diversity, permitting the timely adjustment of management activities to reverse or avoid undesired trends. This paper addresses several related issues bearing on the development of inexpensive and easily implemented monitoring programs for tropical butterflies. First, we discuss the use of butterflies as ecological indicators. Next, we present field evaluations of butterfly sampling techniques, indicating that: (1) light-gap size greatly affects sampling results in forests and should be of critical concern in site selection and sampling design; (2) baited traps and visual censuses provide complementary data on butterfly abundances; (3) monitoring a subset of locally common butterfly species can provide data for comparing community composition and relative abundance of species in areas where species inventories are incomplete. Drawing on these results, we develop guidelines for designing monitoring programs. These address the formulation of explicit questions to be addressed through monitoring and the selection of appropriate study sites, study species, sampling techniques, and sampling frequency. A protocol for the ongoing butterfly monitoring program that emerged from these studies is appended. The techniques and guidelines presented here are intended to serve as an adaptable model for biologists designing monitoring projects to help guide applied conservation efforts in the tropics. 相似文献
306.
Long-term residue of DDT compounds in forest soils in Maine 总被引:3,自引:0,他引:3
Soils in forests sprayed aerially with DDT in 1958-1967 have been sampled for persistence of residues at intervals since then and most recently in 1993. Results of all the samples are presented and show persistence through 30 years, with evidence of decline of residue only in the third decade. The metabolites of DDT--DDE and DDD--increased over time, each comprising about a third of total residue in 1993. Residue continues to be held in the organic mat with little evidence of movement downward to the inorganic soil horizons. 相似文献
307.
Gabbroic bodies in the Bralorne-Gold Bridge area of southwestern British Columbia are associated with the oceanic Bridge River complex of the western Canadian Cordillera, one of the suspect terranes accreted to North America in the Jurassic. The gabbros are locally cut by tonalites and are structurally interleaved with ultramafic rocks, phyllites, graphitic cherts, and carbonate lenses that comprise the lower part of the Bridge River complex. Their late Carboniferous crystallization age overlaps the depositional age of affiliated supracrustal rocks (Mississippian-Jurassic), some of which have been metamorphosed to blueschist facies. Compositionally, the gabbros resemble mafic plutonic rocks of ophiolitic complexes and gabbroic rocks of the nearby Shulaps Range. They display some affinity to oceanic island arc tholeiitic suites. The Bralorne and Shulaps gabbros include cumulates and appear to have been derived from a single, light REE-depleted, peridotitic source by melting and subsequent fractional crystallization/accumulation of various combinations of plagioclase, pyroxenes, and olivine. The tonalites are compositionally distinct from typical ophiolitic plagiogranites, but might be related to the associated gabbros. The gabbroic bodies occur within tectonic slivers derived from the oceanic crust that floored a deep ocean basin that existed during the late Paleozoic and early Mesozoic. The Bridge River complex comprises fragments of oceanic crust that were tectonically incorporated into an east-verging accretionary prism during a middle/late Triassic to Jurassic collisional event. 相似文献
308.
Lee P. Shulman MD Joe Leigh Simpson Richard E. Felker Donald S. Emerson Carole M. Meyers Owen P. Phillips Sherman Elias 《黑龙江环境通报》1992,12(3):229-234
Transvaginal chorionic villus sampling (CVS) using concurrent transabdominal ultrasound guidance was performed in six women who desired CVS but could not be offered transcervical or transabdominal approaches because of uterine position and placental location. Satisfactory amounts of chorionic villi were obtained in all six cases with no maternal discomfort, an occurrence that contrasts with our experience in transvaginal CVS using endovaginal ultrasound guidance. We believe that transvaginal CVS using concurrent transabdominal ultrasound guidance warrants consideration as an alternative technique for first-trimester CVS in selected patients. 相似文献
309.
Diane van Opstal Cardi van den Berg Milena G. J. Jahoda Helen Brandenburg Frans J. Los Peter A. In'T Veld 《黑龙江环境通报》1995,15(1):51-55
Trisomy 18 in direct chorionic villus preparations needs further investigation since the chromosome abnormality may be confined to the placenta and may not represent the actual fetal karyotype. We performed, retrospectively, fluorescent in situ hybridization (FISH) with the chromosome 18 centromere probe (L1.84) on interphase nuclei of destained slides of all cases of full trisomy 18 (n=22) and mosaic trisomy 18 (n=8) detected among 7600 first-trimester chorionic villus samples during an 8-year period (1985–1992). More nuclei displaying three signals were encountered in cases of full and mosaic trisomy 18 confirmed in fetal tissue than in non-confirmed cases. FISH can be useful for the verification of trisomy 18 in direct chorionic villus preparations. 相似文献
310.
Juriy W. Wladimiroff MD Ph.D. Wydia R. Bhaggoe Miranda Kristelijn Titia E. Cohen-Overbeek Nicolette S. Den Hollander Helen Brandenburg Frans J. Los 《黑龙江环境通报》1995,15(5):431-438
Structural pathology and outcome were studied in 170 chromosomally abnormal fetuses. Numerical chromosomal abnormalities were established in 158 (93 per cent) cases, of which 110 (71 per cent) represented trisomies, 30 (18 per cent) Turner syndrome, and 18 (11 per cent) triploidy. Structural chromosomal abnormalities were diagnosed in 12 (7 per cent) cases. Gestational age at referral was significantly shorter for pregnancies with Turner syndrome than for the other chromosomal abnormalities. Referral before 20 weeks of gestation was mainly based on fetal structural pathology alone (92 per cent); after 20 weeks, patients were referred because of structural pathology combined with small for gestational age, oligohydramnios, or polyhydramnios. Referral as a result of suspected multiple organ pathology occurred in 73.5 per cent of pregnancies. An abnormal amniotic fluid volume was present in 59/170 (34.5 per cent) chromosomally affected pregnancies, i.e., oligohydramnios in 31 and polyhydramnios in 28 cases. Birth weight was below the tenth percentile in over half of the chromosomally abnormal fetuses, except for Turnersyndrome. Fetal outcome was poor, with a survival rate at 1 month of 30 per cent for trisomies which was mainly determined by trisomy 21 (14/18=77.5 per cent). 相似文献