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961.
Reducing Nitrogen Export from the Corn Belt to the Gulf of Mexico: Agricultural Strategies for Remediating Hypoxia 下载免费PDF全文
Eileen McLellan Dale Robertson Keith Schilling Mark Tomer Jill Kostel Doug Smith Kevin King 《Journal of the American Water Resources Association》2015,51(1):263-289
SPAtially Referenced Regression on Watershed models developed for the Upper Midwest were used to help evaluate the nitrogen‐load reductions likely to be achieved by a variety of agricultural conservation practices in the Upper Mississippi‐Ohio River Basin (UMORB) and to compare these reductions to the 45% nitrogen‐load reduction proposed to remediate hypoxia in the Gulf of Mexico (GoM). Our results indicate that nitrogen‐management practices (improved fertilizer management and cover crops) fall short of achieving this goal, even if adopted on all cropland in the region. The goal of a 45% decrease in loads to the GoM can only be achieved through the coupling of nitrogen‐management practices with innovative nitrogen‐removal practices such as tile‐drainage treatment wetlands, drainage–ditch enhancements, stream‐channel restoration, and floodplain reconnection. Combining nitrogen‐management practices with nitrogen‐removal practices can dramatically reduce nutrient export from agricultural landscapes while minimizing impacts to agricultural production. With this approach, it may be possible to meet the 45% nutrient reduction goal while converting less than 1% of cropland in the UMORB to nitrogen‐removal practices. Conservationists, policy makers, and agricultural producers seeking a workable strategy to reduce nitrogen export from the Corn Belt will need to consider a combination of nitrogen‐management practices at the field scale and diverse nitrogen‐removal practices at the landscape scale. 相似文献
962.
Ka‐Man Lai Claudia Ramirez Weilong Liu Darina Kirilova David Vick Joe Mari Rachel Smith Ho‐Yin Lam Afshin Ostovari Akifumi Shibakawa Yang Liu Sidharth Samant Lucky Osaro 《Disasters》2015,39(4):648-664
By interpreting disasters as opportunities to initiate the fulfilment of development needs, realise the vulnerability of the affected community and environment, and extend the legacy of relief funds and effort, this paper builds upon the concept linking relief, rehabilitation and development (LRRD) in the sanitation sector. It aims to use a composite of case studies to devise a framework for a semi‐hypothetical scenario to identify critical components and generic processes for a LRRD action plan. The scenario is based on a latrine wetland sanitation system in a Muslim community. Several sub‐frameworks are developed: (i) latrine design; (ii) assessment of human waste treatment; (iii) connective sanitation promotion strategy; and (iv) ecological systems and environmental services for sanitation and development. This scenario illustrates the complex issues involved in LRRD in sanitation work and provides technical notes and references for a legacy plan for disaster relief and development. 相似文献
963.
Davidson Kirklyn B. Holmes Baillie E. J. Spooner Ian S. Dunnington Dewey W. Walker Tony R. Lake Craig B. Su Chih-Chieh 《Environmental science and pollution research international》2021,28(37):51342-51355
Environmental Science and Pollution Research - The paleolimnological method was used to decouple geogenic and anthropogenic metal (loids) contributions in a sediment stabilization basin (Boat... 相似文献
964.
965.
Richard K. F. Unsworth Abigail Powell Femmy Hukom David J. Smith 《Marine Biology》2007,152(2):243-254
This paper used the case study of the Wakatobi Marine National Park, Indonesia to examine changes in the diversity, density
and maturity of grouper species over a 5-year period following the establishment of a small-scale no-take area (NTA). This
work was carried out to investigate whether “small” NTAs could be effective management strategies over a time scale that is
relevant to local fishery communities and their perception of management success. Our research also documents the ecology
of these species, information essential if we are to understand how management practises are to affect coral reef fish species.
Designation of this “small NTA” increased the density of groupers by 30% over a 5-year period of protected status. After 5 years
of protection, grouper populations within this NTA were more mature and double the density of those within the adjacent lightly
fished sites and nearly five times those of a heavily fished site. During this time all other nearby fished sites underwent
large declines in grouper density. The nearby lightly fished Kaledupa site decreased by up to 50% year−1. Such drastic declines are considered the impact of the exponential development of ever efficient and unsustainable methods
of fishing within the study region. This NTA was not of benefit to all grouper species; the reasons for which are not clear.
Such questions require further detailed research about the life history, population and behavioural ecology of Indo-Pacific
grouper species. Such information is critical for urgently needed fisheries management. The present study found that a small
scale NTA of 500 m length was large enough to increase the population of top predatory fish. In conjunction with other socially
acceptable small scale NTAs it could help maintain and increase important fish stocks over a larger area. The use of “small”
NTAs within networks of reserves should become a useful tool in the management of the locally exploited coral reefs. 相似文献
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967.
968.
Non-mosaic trisomy 22 is a common cause of first trimester miscarriage and has a livebirth incidence of 1 in 30 000–50 000. Consequently there is a paucity of information for counselling parents. Detection in the second trimester is rare. It is commonly associated with severe growth retardation and multiple structural abnormalities. Oligohydramnios is frequently seen and can make detection of other abnormalities difficult. The outlook is uniformly poor and survival beyond the first trimester may present management dilemmas. A thorough fetal assessment including high-resolution cytogenetics with or without FISH is required for counselling. Careful plans for intrapartum and neonatal management may be necessary. The recurrence risk is thought to be low but information is very limited as there have been no reported cases of recurrence. We present two case of non-mosaic trisomy 22 including the first to be diagnosed subsequent to investigation for a high serum screening Down's risk. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
969.
970.
Adaptive host choice and avoidance of superparasitism in the spawning decisions of bitterling (Rhodeus sericeus) 总被引:5,自引:0,他引:5
C. Smith John D. Reynolds William J. Sutherland Pavel Jurajda 《Behavioral ecology and sociobiology》2000,48(1):29-35
Choice of a site for oviposition can have fitness consequences. We investigated the consequences of female oviposition decisions
for offspring survival using the bitterling, Rhodeus sericeus, a freshwater fish that spawns inside living unionid mussels. A field survey of nine bitterling populations in the Czech
Republic revealed a significantly lower rate of release of juvenile bitterling from Anodonta cygnea compared to three other mussel species. A field experiment demonstrated that female bitterling show highly significant preferences
for spawning in A. anatina, Unio pictorum, and U. tumidus. Within a species, female bitterling avoided mussels containing high numbers of bitterling embryos. Mortality rates of bitterling
embryos in mussels were strongly density dependent and the strength of density dependence varied significantly among mussel
species. Female preferences for mussels matched survival rates of embryos within mussels and females distributed their eggs
among mussels such that embryo mortalities conformed to the predictions of an ideal free distribution model. Thus, female
oviposition choice is adaptive and minimizes individual embryo mortality.
Received: 6 October 1999 / Received in revised form: 7 January 2000 / Accepted: 13 March 2000 相似文献