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491.
A prominent interaction in the lives of social mammals is allogrooming. Individuals allogroom strategically and preferentially,
grooming high-quality individuals that control access to resources. This results in distinct patterns of allogrooming within
social groups, such that some individuals are groomed more than the others, some dyads express symmetry in allogrooming, and
others exchange allogrooming for other benefits. Allopreening, the avian equivalent of allogrooming, occurs commonly in group-living
birds, providing the opportunity to test whether social birds also use allopreening strategically in their social relationships.
I examined this hypothesis in family-living buff-breasted wrens (Cantorchilus leucotis) by examining allopreening initiation, reciprocation and rate during interactions involving breeding adults and offspring.
Buff-breasted wrens exhibit a nuclear family structure in which pairs display long-term partnerships, and juveniles delay
dispersing from natal territories for about 10 months. Allopreening was symmetrical between breeding partners: males and females
who initiated and reciprocated allopreening of partners with similar frequency, and within reciprocated bouts, allopreening
was time-matched. Pairs in which allopreening was not observed were more likely to divorce, but allopreening patterns did
not change in successive years of partnerships. Parent–offspring allopreening, by contrast, was asymmetrical in pattern; parents
initiated allopreening more than their offspring, and reciprocation never occurred. The different patterns of allopreening
observed within buff-breasted wren families suggest the strategic use of allopreening, possibly for the maintenance of long-term
partnerships and in exchange for social benefits from offspring. 相似文献
492.
Concei??o Juana Fortes óscar Ferreira Paulo A. Silva Theo Moura Rui Capit?o Luís Amante Michalis Vousdoukas Maria Bezerra 《Journal of Coastal Conservation》2012,16(4):461-472
In the framework of a research project entitled ??BRISA??BReaking waves and Induced SAnd transport??, a methodology was devised to characterize the waves joining together in-situ measurements and numerical wave propagation models. With this goal in mind, a number of in-situ measurements were made, for selected positions in front of Praia de Faro (South Portugal), during four days (25th to 28th March, 2009) by using different types of equipments (e.g., resistive wave gauges, pressure sensors, currentmeters and a new prototype pore pressure sensor using optical fibre). Wave records were obtained simultaneously offshore (at a water depth of 11.7?m below mean sea level, MSL) and at the surf and swash zones. The data processing and analysis were made by applying classical time domain techniques. Numerical simulations of the wave propagation between offshore and inshore for the measurement period were performed with two numerical models, a 1D model based on linear theory and a nonlinear Boussinesq-type model, COULWAVE, both forced by the measured offshore wave conditions of 27th March 2009. Comparisons between numerical results and field data for the pressure sensors placed in the surf and swash zones were made and discussed. This approach enables to evaluate the performance of those models to simulate those specific conditions, but also to validate the models by gaining confidence on their use in other conditions. 相似文献
493.
Portugal is strongly vulnerable to sea hazards due to intense vessel traffic and sea conditions. The southwest region off the Iberian Peninsula lies in the main route from the Mediterranean and Southern Hemisphere to the Northern Europe, causing a ship concentration in a narrow band off Cape S?o Vicente. Tankers represent a significant part of the vessel traffic and the occurrence of oil spills cannot be disregarded. Cape S?o Vicente region is part of a Natural Park with 110 Km of coastline, integrated in the European Natura 2000 network and its socio-economic context is closely related with sea resources exploitation, particularly fishing and tourism. Recognizing the importance of accurate information systems for the decision making process in an oil spill situation, this work presents the development of an integrated tool to support the process in the Algarve coast. The system relies in a regional operational mathematical model based on the MOHID modelling system. The system core is composed by three models (3D hydrodynamics, wave and Lagrangian transport) all linked in the same system and exchanging information in real time. Oil advection and weathering processes are coupled to the Lagragian transport model. The overall operational system includes external operational data products as inputs, to ensure a successful validation of the results. The system is linked to stakeholders and response authorities using a geographic referenced database based on Mapserver technology that will include relevant information for oil spill management. 相似文献
494.
Milan Novakovi? Muftah Mohamed Ali Ramadan Tatjana ?olevi? Knudsen Mali?a Anti? Vladimir Be?koski Gordana Gojgi?-Cvijovi? Miroslav M. Vrvi? Branimir Jovan?i?evi? 《Environmental Chemistry Letters》2012,10(3):287-294
Phenanthrene and methyl-phenanthrenes are major aromatic pollutants originating in particular from fuel oil. Phenanthrene is usually degraded faster than methyl-phenanthrenes under geological and environmental conditions. Here, we report a preferential and accelerated biodegradation of methyl-phenanthrenes versus phenanthrene in soil contaminated by fuel oil. The polluted soil was mixed with sawdust and sand to form a homogenized biopile. The biopile was continuously sprayed with microbial consortia isolated from crude oil?Ccontaminated soil and treated by biosurfactants and nutritive substances for biostimulation. During a 6-month bioremediation experiment, a steady increase in the relative abundance of phenanthrene compared to methyl-phenathrenes was observed by gas chromatography?Cmass spectrometry. The increase was the highest for trimethyl-phenanthrenes, with a phenanthrene/trimethyl-phenanthrenes ratio increasing from 0.42 to 2.45. By contrast, the control, non-stimulated samples showed a ratio decrease from 0.85 to 0.11. Moreover, the results showed that the level of degradability depends on the number of methyl groups. 相似文献
495.
Ivan Viegas Sónia Cotrim Marques Filipa Bessa Ana Lígia Primo Filipe Martinho Ulisses Miranda Azeiteiro Miguel ?ngelo Pardal 《Marine Biology》2012,159(1):33-43
This study provides a comprehensive examination of the life cycle dynamics of the brown shrimp (Crangon crangon L.) in the Mondego estuary, Portugal, a habitat located near the southern edge of the range of this species in European waters.
The phenology of all life stages was documented (from the occurrence of ovigerous females, developing embryos, planktonic
larvae and benthic post-larvae), and migration patterns of larvae into and out of the estuary were examined. Temperature-dependent
functions of egg and larval development were combined with data on field abundance to predict the timing and magnitude of
occurrence of larvae and recruits. Compared to brown shrimp at higher latitudes, southern conspecifics grow slower, mature
earlier and have smaller brood sizes, and larvae have a more protracted settlement period. The Mondego estuary, besides acting
as nursery area, is a dynamic platform for C. crangon to use in different stages, sizes and seasons. 相似文献
496.
Direct and indirect methods have been used to describe patterns of movement of fishes, but few studies have compared these
methods simultaneously. We used 20 years of trawl survey data and 1 year of acoustic telemetry data to evaluate the vertical
and horizontal movement patterns of spotted ratfish Hydrolagus colliei in Puget Sound, WA, USA. Densities of large ratfish (≥30 cm) were higher at the deepest depths trawled (70 m) during daylight
hours, whereas densities were similar across depth zones (to 10 m) at night. Acoustic tracking of ratfish showed distinct
diel patterns of movement and activity level; ratfish moved into shallow, nearshore habitats at night from deeper, offshore
habitats during the day and made ~3 times more moves at night than day in shallow habitats. Broader spatial patterns depended
on where ratfish were tagged: one tag group remained in one general location with few excursions, whereas a second tag group
moved within a 20-km band with some individuals moving >90 km. These data will help inform food web models’ abilities to quantify
interspecific interactions between ratfish and other components of their community. 相似文献
497.
Alexandra?ZieritzEmail author Gemma?Clucas Lauren?Axtmann David?C.?Aldridge 《Marine Biology》2012,159(4):863-872
When feeding on blue mussels (Mytilus edulis), oystercatchers (Haematopus ostralegus) either stab into the mollusc’s gaping valves or hammer through its dorsal or ventral shell. Whilst the selectivity of hammering
and stabbing oystercatchers for specific prey morphologies has been well studied, the way in which the effects of environment
on M.
edulis morphology can in turn affect feeding methods of H. ostralegus is very poorly understood. Based on morphological analyses on randomly selected shells from three intertidal zones, this
study failed to detect differences in morphology or distribution of dorsally and ventrally hammered shells but confirms the
finding of previous authors that hammering oystercatchers select thinner mussels than stabbing birds. Additionally, we show
that this difference in optimal prey morphology can lead to spatial patterns in oystercatcher feeding behaviour. Whilst at
the low intertidal and higher mid intertidal zones, characterised by comparatively thick shells, most empty shells had apparently
been stabbed, hammering was the dominant feeding behaviour at the lower mid intertidal zone, where shells were thinner. Preference
of hammering birds for smaller mussels was not ubiquitous. Sagittal shell shape was predominantly influenced by allometric
growth effects and had only minor effect on prey selection. All oystercatchers preferred less inflated mussels, with the degree
of shell inflation gradually increasing with higher intertidal elevation. Our results illustrate the importance of small-scale
patterns in prey ecophenotypes in determining the distribution and feeding dynamics of wading birds. 相似文献
498.
Bailey?C.?McMeansEmail author Michael?T.?Arts Scott?A.?Rush Aaron?T.?Fisk 《Marine Biology》2012,159(5):1095-1105
The marine copepod Calanus hyperboreus accumulates large quantities of lipids and essential fatty acids during summer months in Northern oceans. However, few data
exist regarding their winter fatty acid profiles, which could be informative regarding the use of lipids by C. hyperboreus to successfully survive and reproduce during times of ice-cover and limited food. The present study compared fatty acids
of C. hyperboreus between summer (August 2007 and 2008) and winter (early April 2008 and 2009) in Cumberland Sound, Canada. Summer samples
from both years had significantly higher ∑polyunsaturated fatty acids and unsaturation indices (based on μg fatty acid mg
dry tissue−1) than winter samples and separated on a principal component analysis due to higher 18:2n-6, 18:4n-3, and 20:5n-3, consistent
with phytoplankton consumption. Winter C. hyperboreus had significantly higher ∑monounsaturated fatty acids (MUFA) versus summer samples and separated on the principal component
analysis due to higher proportions of 16:1n-7, 20:1n-9, and 22:1n-9, suggesting they were not actively feeding. Based on the
seasonal fatty acid comparison, C. hyperboreus was catabolizing specific fatty acids (e.g. 20:5n-3), conserving others (e.g. 22:6n-3), and maintaining or increasing biosynthesis
of certain MUFA (e.g. 18:1n-9) during winter. These findings provide insight into the seasonal strategy of acquisition (summer)
and utilization (winter) of specific fatty acids by a key Arctic organism and could become important for monitoring changes
in fatty acids associated with decreased ice-cover duration due to climate warming. 相似文献
499.
Michael?D.?ArendtEmail author Albert?L.?Segars Julia?I.?Byrd Jessica?Boynton J.?David?Whitaker Lindsey?Parker David?W.?Owens Ga?lle?Blanvillain Joseph?M.?Quattro Mark?A.?Roberts 《Marine Biology》2012,159(1):127-139
Thirty-four juvenile loggerhead sea turtles captured by trawling from the Charleston, South Carolina (USA), shipping channel
(32°42′N; −79°47′W) between May 2004 and August 2007 were tagged with satellite transmitters to assess the extent to which
they remained near the capture location given their collection along a seasonal migratory corridor. Seventy-five percent of
juveniles were classified as seasonal residents. Migrants predominantly swam north in the spring and nomads wandered south
in the summer, but predictive indicators for non-resident status were not identified. All but one juvenile generally remained
south of 34°N, within 40 km of shore, and in waters <30 m deep throughout the year. Nine of 14 loggerhead sea turtles monitored
during the winter remained exclusively over the continental shelf, three briefly occurred in oceanic habitats, and two foraged
extensively in oceanic habitats. Residents distributed >15 km from shore between spring and autumn were three times as likely
to occur in oceanic habitats in winter. Modest seasonal movements contrasted with adults tagged at similar latitudes and with
juveniles tagged further north and suggest distinct foraging groups within a regional foraging ground. 相似文献
500.
Understanding physiological and environmental variables that initiate sexual maturity would provide fundamental information
on life history dynamics. The aim of this study was to test the usefulness of the common circumnuclear ring (CNR), an oocytic
structure similar to the Balbiani body, which appears just prior to oocyte development as a predictor of first maturation
in Atlantic herring (Clupea harengus). The relative roles of physiology (e.g. fat) and photoperiod as triggers of maturation were also investigated. Samples were
collected in May 2008 (72°26′–73°84′N/11°26′–18°40′E) and February 2009 (56°12′–59°45′N/00°25′–03°06′W). These data suggested
that thresholds in body size may influence the decision to mature. We also found that short days (winter solstice) may be
the photoperiod trigger for a first-decision window for both Norwegian spring-spawning (NSS) and North Sea autumn-spawning
(NSAS) herring. The second-decision window for NSAS herring maturation appears to be triggered by longer days (spring equinox),
while a decreasing rate of day lengthening may trigger NSS herring maturation. So, photoperiodic cycle is a key determinate
of the timing of maturation in Atlantic herring. 相似文献