全文获取类型
收费全文 | 766篇 |
免费 | 10篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 59篇 |
废物处理 | 42篇 |
环保管理 | 137篇 |
综合类 | 67篇 |
基础理论 | 230篇 |
环境理论 | 1篇 |
污染及防治 | 155篇 |
评价与监测 | 62篇 |
社会与环境 | 23篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 9篇 |
2016年 | 17篇 |
2015年 | 13篇 |
2014年 | 19篇 |
2013年 | 76篇 |
2012年 | 23篇 |
2011年 | 46篇 |
2010年 | 31篇 |
2009年 | 26篇 |
2008年 | 28篇 |
2007年 | 31篇 |
2006年 | 50篇 |
2005年 | 21篇 |
2004年 | 18篇 |
2003年 | 26篇 |
2002年 | 33篇 |
2001年 | 23篇 |
2000年 | 27篇 |
1999年 | 12篇 |
1998年 | 15篇 |
1997年 | 12篇 |
1996年 | 12篇 |
1995年 | 13篇 |
1994年 | 10篇 |
1993年 | 9篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1990年 | 11篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 8篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 11篇 |
1983年 | 5篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 4篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1969年 | 3篇 |
排序方式: 共有780条查询结果,搜索用时 15 毫秒
731.
The plant family Orobanchaceae includes many parasitic weeds that are also impressive invaders and aggressive crop pests with several specialized features (e.g. microscopic seeds, parasitic habits). Although they have provoked several large-scale eradication and control efforts, no global evaluation of their invasive potential is as yet available. We use tools from ecological niche modeling in combination with occurrence records from herbarium specimens to evaluate the global invasive potential of each of 10 species in this assemblage, representing several of the worst global invaders. The invasive potential of these species is considerable, with all tropical and subtropical countries, and most temperate countries, vulnerable to invasions by one or more of them. 相似文献
732.
Burning seaweed to produce kelp, valued for its high potash and soda content, was formerly a significant industry in remote coastal areas of Scotland and elsewhere. Given the high concentrations of arsenic in seaweeds, up to 100 mg kg(-1), this study investigates the possibility that the kelp industry caused arsenic contamination of these pristine environments. A series of laboratory-scale seaweed burning experiments was conducted, and analysis of the products using HPLC ICP-MS shows that at least 40% of the arsenic originally in the seaweed could have been released into the fumes. The hypothesis that the burning process transforms arsenic from low toxicity arsenosugars in the original seaweeds (Fucus vesiculosus and Laminaria digitata) to highly toxic inorganic forms, predominantly arsenate, is consistent with As speciation analysis results. A field study conducted on Westray, Orkney, once a major centre for kelp production, shows that elevated arsenic levels (10.7+/-3.0 mg kg(-1), compared to background levels of 1.7+/-0.2 mg kg(-1)) persist in soils in the immediate vicinity of the kelp burning pits. A model combining results from the burning experiments with data from historical records demonstrates the potential for arsenic deposition of 47 g ha(-1) year(-1) on land adjacent to the main kelp burning location on Westray, and for arsenic concentrations exceeding current UK soil guideline values during the 50 year period of peak kelp production. 相似文献
733.
Objective: The Lower Anchor and Tethers for CHildren (LATCH) system was introduced in vehicles made after September 1, 2002 and intended to make installation of rear and forward-facing child safety seats easier. Due to the lack of rear impact testing of RFCRS required per the Federal Motor Vehicle Safety Standards (FMVSS), the purpose of this study was to explore the effects, if any, of installation method of RFCRS on the performance of commonly purchased makes and models of RFCRS. Specifically, we hypothesize that in a 48 km/h (29.8 MPH) rear-end collision, installation of RFCRS using the LATCH system will result in higher Head Injury Criteria (HIC) values when compared to using the available lap/shoulder seatbelt (Emergency Locking Retractor - ELR or Automatic Locking Retractor - ALR).Methods: The test matrix included 36 rear impact sled tests conducted using 3 installation methods on 3 models of RFCRS: the Graco SnugRide® with and without the base, the Britax Chaperone with base-mounted anti-rebound bar, and the Evenflo Tribute®, a model of convertible rearward/forward facing restraint system used in the rearward facing mode. The seats were installed using the LATCH system, ELR lap/shoulder belts, or ALR lap/shoulder belts in seating positions 4 and 6 on a vehicle buck mounted to the sled test base. The infant seat and 6 month old CRABI anthropometric test device (ATD) installation methods were in accordance with standards set forth in the National Highway Traffic Safety Administration's (NHTSA) FMVSS No. 213, Child Restraint Systems. All tests were conducted on pneumatic controlled acceleration sled (HYGE, Inc., PA, USA) at 48 km/h.Results: Installation of infant seat type RFCRS using the LATCH system resulted in higher HIC15 values when compared to using the available lap/shoulder seatbelt (ELR or ALR). The mean HIC15 values were most severe when infant seat type RFCRS were installed using LATCH (Graco SnugRide® HIC15 = 394 and Britax Chaperone HIC15 = 133) compared to using either ELR lap/shoulder belts (Graco SnugRide® HIC15 = 218 and Britax Chaperone HIC15 = 65) or ALR lap/shoulder belts (Graco SnugRide® HIC15 = 194 and Britax Chaperone HIC15 = 78). The installation method did not result in a statistically significant difference in HIC for the convertible type RFCRS (Evenflo Tribute®). In many of the tests, the ATD's head struck the seatback in which the RFCRS was installed. These head strikes resulted in the higher HIC15 scores recorded throughout the testing.Conclusions: The results of this study suggest that LATCH does not offer equal protection to lap/shoulder belts from head injuries in rear impacts when used with infant seat type RFCRS. 相似文献
734.
Robert?K.?DixonEmail author Richard?M.?Scheer Gareth?T.?Williams 《Mitigation and Adaptation Strategies for Global Change》2011,16(1):83-102
Addressing energy, economic and environment security is a pressing challenge for nations worldwide. Global energy demand is
projected to increase by 45% during the next 20 years, with the fastest growth in developing and transition countries. Over
the past two decades, the Global Environment Facility (GEF) has invested in a portfolio of sustainable energy projects with
an emphasis on energy efficiency, renewable energy, and urban transport. These projects address many different national priorities
including infrastructure, technologies, policies, best practices, institutions, and capacity building. Since 1991, more than
US2,735 billion has been invested in energy sector projects with an additional US2,735 billion has been invested in energy sector projects with an additional US17.118 billion in co-financing from governments
and the private sector. US1,186 billion, together with US1,186 billion, together with US7,092 billion in co-finance, has been invested in energy efficiency
projects that deploy new technologies, develop institutional and human capacity, disseminate best practices, and build public
awareness and understanding. GEF renewable energy investments of US1,298 billion, with co-financing of US1,298 billion, with co-financing of US7,555 billion,
have advanced demonstration and deployment of solar thermal heating, solar thermal power, photovoltaics, wind power, geothermal
energy, small hydropower, biomass, and combined technologies and best practices across 5 continents. The GEF has invested
US251 million (with US251 million (with US2,471 billion in co-finance) in urban transport projects that address transport strategies, infrastructure,
and mobility technology solutions. These energy efficiency, renewable energy and urban transport projects contributed to the
direct reduction of about 1.7 billion tons of greenhouse gas emissions. Other tangible environmental benefits also flowed
from these GEF investments. Case studies of representative projects are presented to illustrate lessons learned from the energy
efficiency, renewable, energy, and urban transport investments. Experiences from GEF investments can inform development and
implementation of future sustainable energy investments. 相似文献
735.
Connectedness to nature,place attachment and conservation behaviour: Testing connectedness theory among farmers 总被引:3,自引:0,他引:3
The aim of this study was to explore the relationship between pro-environmental behaviour and two forms of emotional association: attachment to place and connectedness to nature. This relationship is explored in the context of farmers' management of native vegetation on their properties. A postal survey was conducted to measure the extent to which farmers felt connected to nature and to their property. The survey also measured vegetation management behaviours and associated valued outcomes. A total of 141 farmers in northwest Victoria, Australia, completed the survey. Results showed that vegetation protection behaviours increased with connectedness to nature (CNS), although CNS accounted for only a modest amount of the variation in behaviour. Place attachment was not related to management behaviours. Further analysis suggested that the relationship between CNS and management behaviour was mediated by importance given to environmental benefits of vegetation management. The findings lend weight to studies showing a relationship between CNS and more simple conservation behaviours (e.g. recycling). The findings are also consistent with frameworks suggesting that emotional association with nature leads to an expanded sense of self and greater valuing of non-human species, and so to pro-environment behaviour. This demonstrates the importance of using a range of instrumental and more affective strategies to promote conservation behaviours. 相似文献
736.
Nicola A. Clark Mark Williams Daniel J. Hill Patrick G. Quilty John L. Smellie Jan Zalasiewicz Melanie J. Leng Michael A. Ellis 《Die Naturwissenschaften》2013,100(8):699-722
We evaluate the available palaeontological and geochemical proxy data from bivalves, bryozoans, silicoflagellates, diatoms and cetaceans for sea surface temperature (SST) regimes around the nearshore Antarctic coast during the late Neogene. These fossils can be found in a number of shallow marine sedimentary settings from three regions of the Antarctic continent, the northern Antarctic Peninsula, the Prydz Bay region and the western Ross Sea. Many of the proxies suggest maximum spring–summer SSTs that are warmer than present by up to 5 °C, which would result in reduced seasonal sea ice. The evidence suggests that the summers on the Antarctic shelf during the late Neogene experienced most of the warming, while winter SSTs were little changed from present. Feedbacks from changes in summer sea ice cover may have driven much of the late Neogene ocean warming seen in stratigraphic records. Synthesized late Neogene and earliest Quaternary Antarctic shelf proxy data are compared to the multi-model SST estimates of the Pliocene Model Intercomparison Project (PlioMIP) Experiment 2. Despite the fragmentary geographical and temporal context for the SST data, comparisons between the SST warming in each of the three regions represented in the marine palaeontological record of the Antarctic shelf and the PlioMIP climate simulations show a good concordance. 相似文献
737.
M. Katharine Rudd Justin B. Schleede Sabrina R. Williams Kristy Lee Jennifer Laffin Romela Pasion Peter R. Papenhausen 《黑龙江环境通报》2018,38(12):920-923
Noninvasive prenatal testing accurately detects trisomy for chromosomes 13, 21, and 18, but has a significantly lower positive predictive value for monosomy X. Discordant monosomy X results are often assumed to be due to maternal mosaicism, usually without maternal follow-up. We describe a case of monosomy X-positive noninvasive prenatal testing that was discordant with the 46,XX results from amniocentesis and postnatal testing. This monosomy X pregnancy doubled the single X chromosome, leading to 45,X/46,XX mosaicism in the placenta and uniparental isodisomy X in the amniotic fluid. Thus, at least some discordant monosomy X results are due to true mosaicism in the pregnancy, which has important implications for clinical outcome and patient counseling. 相似文献
738.
Meryl J. Williams 《Ambio-人类环境杂志》2002,31(4):337-339
引言 以下三篇文章分别对海岸带生态系统、人口变化和科学技术发展对海岸带资源利用影响之间的复杂关系进行综合论述. 相似文献
739.
Behavioral genomics of honeybee foraging and nest defense 总被引:8,自引:1,他引:8
Hunt GJ Amdam GV Schlipalius D Emore C Sardesai N Williams CE Rueppell O Guzmán-Novoa E Arechavaleta-Velasco M Chandra S Fondrk MK Beye M Page RE 《Die Naturwissenschaften》2007,94(4):247-267
The honeybee has been the most important insect species for study of social behavior. The recently released draft genomic
sequence for the bee will accelerate honeybee behavioral genetics. Although we lack sufficient tools to manipulate this genome
easily, quantitative trait loci (QTLs) that influence natural variation in behavior have been identified and tested for their
effects on correlated behavioral traits. We review what is known about the genetics and physiology of two behavioral traits
in honeybees, foraging specialization (pollen versus nectar), and defensive behavior, and present evidence that map-based
cloning of genes is more feasible in the bee than in other metazoans. We also present bioinformatic analyses of candidate
genes within QTL confidence intervals (CIs). The high recombination rate of the bee made it possible to narrow the search
to regions containing only 17–61 predicted peptides for each QTL, although CIs covered large genetic distances. Knowledge
of correlated behavioral traits, comparative bioinformatics, and expression assays facilitated evaluation of candidate genes.
An overrepresentation of genes involved in ovarian development and insulin-like signaling components within pollen foraging
QTL regions suggests that an ancestral reproductive gene network was co-opted during the evolution of foraging specialization.
The major QTL influencing defensive/aggressive behavior contains orthologs of genes involved in central nervous system activity
and neurogenesis. Candidates at the other two defensive-behavior QTLs include modulators of sensory signaling (Am5HT
7
serotonin receptor, AmArr4 arrestin, and GABA-B-R1 receptor). These studies are the first step in linking natural variation in honeybee social behavior
to the identification of underlying genes. 相似文献
740.
Hannah B. Vander Zanden Joseph B. Pfaller Kimberly J. Reich Mariela Pajuelo Alan B. Bolten Kristina L. Williams Michael G. Frick Brian M. Shamblin Campbell J. Nairn Karen A. Bjorndal 《Marine Biology》2014,161(3):585-598
Diet items and habitat constitute some of the environmental resources that may be used differently by individuals within a population. Long-term fidelity by individuals to particular resources exemplifies individual specialization, a phenomenon that is becoming increasingly recognized across a wide range of species. Less is understood about the consequences of such specialization. Here, we investigate the effects of differential foraging ground use on reproductive output in 183 loggerhead sea turtles (Caretta caretta) nesting at Wassaw Island, Georgia (31.89°N, 80.97°W), between 2004 and 2011 with resulting possible fitness effects. Stable isotope analysis was used to assign the adult female loggerheads to one of three foraging areas in the Northwest Atlantic Ocean. Our data indicate that foraging area preference influences the size, fecundity, and breeding periodicity of adult female loggerhead turtles. We also found that the proportion of turtles originating from each foraging area varied significantly among the years examined. The change in the number of nesting females across the years of the study was not a result of uniform change from all foraging areas. We develop a novel approach to assess differential contributions of various foraging aggregations to changes in abundance of a sea turtle nesting aggregation using stable isotopes. Our approach can provide an improved understanding of the influences on the causes of increasing or decreasing population trends and allow more effective monitoring for these threatened species and other highly migratory species. 相似文献