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561.
562.
A fetus with mucopolysaccharidosis type IV A (Morquio type A) is described. The family had one affected child exhibiting symptoms of classical Morquio A disease, and late in the subsequent pregnancy prenatal diagnosis was requested. At 23 weeks' gestation, moderate ascites was detected by detailed ultrasound scan and keratan sulphate was found in the amniotic fluid. The pregnancy was terminated by prostaglandin induction and the diagnosis of mucopolysaccharidosis type IV A was confirmed by demonstration of a deficiency of N-acetylgalactosamine-6-sulphate (GalNac-6-S) sulphatase in cultured amniotic cells and in post-mortem fibroblast cultures. The activities of β-galactosidase and arylsulphatase A were normal, ruling out Morquio disease type B and multiple sulphatase deficiency. These results indicate that mucopolysaccharidosis IV A (a disease that predominantly affects the skeletal system) may produce ascites in the fetus to such an extent that it can be detected by ultrasound.  相似文献   
563.
新西兰卫生部已宣布,从2001年12月7日起,将对所有转基因食品,即该食品最终成品中引入了新的DNA或异源蛋白,实行强制标签制度。任何进口和国产的食品只要含有转基因成分都将要求贴上标签。新西兰食品主管部门在2000年12月上旬根据食品标准法典18款修正案(转基因技术生产的食品法规)公布了以上决定。  相似文献   
564.
The aim of the study was to delineate soil landscape constraints to various land uses for urban and regional planning in the coastal areas of New South Wales (NSW), Australia. Soil landscape units mapped at 1:100,000 or coarser were sub-divided into component facets using advanced terrain modelling techniques in a geographic information system (GIS). The output facet grids were further overlain and linked with relevant GIS layers and soil databases to derive soil landscape constraint ratings for various land use purposes such as residential development, cropping and grazing. The constraint ratings for a specific land use were calculated based on objective and rule-based assessments of soil and landscape features such as engineering hazards, intrinsic fertility, drainage and other parameters. A series of soil landscape constraint maps which portray specific land use capability have been produced for the NSW coast. The methodology developed in this study has been demonstrated to be efficient in delineating soil landscape constraints and there is over 90% agreement between the model outputs and the assessment by soil surveyors with local knowledge. The output maps show levels of unprecedented detail of soil and landscape constraint for the coast of NSW and can be readily interpreted by land use planners and land managers for sustainable land use decision making practices.  相似文献   
565.
C. M. Young 《Marine Biology》1989,102(4):481-489
Ascidian densities were manipulated while controlling for negative effects of biodeposition and space preemption to examine the effects of ascidian filter-feeding on larval recruitment in St. Joseph Bay and near Turkey Point, Florida (Northern Gulf of Mexico, Florida, USA). Using three different experimental designs during 1984 and 1985, recruitment near living Styela plicata or Molgula occidentalis was as high as recruitment near ascidian models. Disruption of flow by ascidian bodies had little effect on settlement. Predation rates by ascidians on larvae in six phyla were high in laboratory experiments. The field effects of larval depletion by solitary ascidians are apparently obscured by other factors influencing the abundance of recruiting larvae. Consumption of larvae in the laboratory cannot be used to assume significant inhibitory effects in the field.  相似文献   
566.
It is predicted that deep-sea animals adapted to thermally stable conditions should be highly sensitive to temperature change and should not have inducible heat-shock responses. This premise was tested with the cold-seep mussel Bathymodiolus childressi Gustafson, 1998 from 750 m depth in the Gulf of Mexico at a site known as Brine Pool NR-1 (27°43.4157N, 91°16.756W). Mussels were collected during February 2003. Site temperature, measured in different months between 1995 and 2005, ranged between 6.5 and 7.2°C. Although Brine Pool NR-1 is stenothermal, hydrogen sulfide, oxygen, and salinity vary over temporal and spatial scales. In laboratory experiments, B. childressi survived increases up to approximately 20°C above ambient temperature for 6 h before suffering greater than 50% mortality. Although a high thermal tolerance was observed, B. childressi did not express an inducible 70 kDa heat-shock protein. However, high constitutive levels of hsp70 were present in B. childressi suggesting a necessity to remediate protein damage from stressors other than elevated temperature; these constitutive proteins probably confer an indirect thermal tolerance.  相似文献   
567.
The distribution and abundance of the littorinid gastropod Cenchritis (Tectarius) muricatus were determined on an exposed shore at Lee Stocking Island, Bahamas in July/August 1995 and June 1999. Activity patterns were observed on two occasions shortly before a hurricane passed near the island in 1995. C. muricatus extended from the low water mark to 3.6 m vertical height above it. Highest densities (20/m2) were found just above the high tide mark but the animal remained relatively abundant (8/m2) at the highest point. Small animals were only found at high shore levels. With the exception of animals very near to the water's edge C. muricatus was inactive by day and on dry nights. Many individuals of the high shore populations became active at night during periods of high humidity and rainfall, moving distances of up to 4 m overnight. At lower levels, extensive pairing and copulation was associated with these periods of rainfall. Abundance changed dramatically after the passage of the hurricane. At the level of maximum abundance numbers were reduced from 20/m2 to 2.8/m2. Long-term experimental studies of water loss rate and haemolymph concentration showed that both water loss rate and increase in haemolymph concentration are greatest in the early period of desiccation. The concentration of the blood after 20 weeks is 250% of the original and the water lost is of the order of 22.5%. After an initial increase there appears to be evidence of regulation of haemolymph concentration possibly by exchange with free water in the shell itself. The considerable reserve capacity in tolerance is no doubt in part due to the structure and functioning of the kidney. Adaptive features of the excretory system identified from ultrastructural examination include the replacement of podocyte-containing filtration chambers in the auricle by extracellular tubules permeating the walls of both auricle and ventricle, which suggests a reduction in the rate of primary urine formation. This is also indicated by a reduced surface area of the nephridial gland, which resorbs organic solutes from the urine. Excretory cells contain single large vacuoles in which arise large multi-layered concretions composed of phospholipids and calcium salts typical of prosobranchs in which excretory products may be stored for long periods.  相似文献   
568.
Animal-sediment relations in Cape Cod Bay,Massachusetts I. A transect study   总被引:1,自引:0,他引:1  
Benthic macrofauna and bottom sediments were sampled at 7 stations along a 24 km long onshore-offshore transect ranging in depth from 12 to 42 m in Cape Cod Bay, Massachusetts, USA. High faunal density, biomass and species diversity were recorded at stations densely populated by tubicolous polychaetes. These tube mats bind and stabilize the substratum, providing solid surfaces for attachment of epizoans. Three suspension-feeding species, Euchone incolor (polychaete), Thyasira gouldi (bivalve) and Aeginina longicornis (amphipod), co-occur with deposit-feeding species on muds resuspended by tidal currents. Hydrographic profiles of temperature, salinity and turbidity indicate that resuspended silt-clay particles are entrapped in dense water below the summer thermocline, which persists from mid-April to mid-October. The zone of intersection of the thermocline with the sea floor in about 22 m of water defines a major biofacies-lithofacies transition. This ecotone is characterized by high faunal density, biomass, and species diversity. Benthic populations of macrofauna from Cape Cod Bay are larger than those from Buzzards Bay, Massachusetts, and have a widely different taxonomic and trophic composition.Contribution No. 235 of the Systematics-Ecology Program, Marine Biological Laboratory, Woods Hole, Massachusetts, USA.  相似文献   
569.
The feeding ecology of Maurolicus muelleri, Lampanyctodes hectoris and Diaphus danae was examined from samples collected from continental slope waters of eastern Tasmania between April 1984 and April 1985. A total of 2 232 stomachs was analysed. M. muelleri, L. hectoris and D. danae fed primarily on euphausiids and secondarily on copepods, although larger D. danae (> 60 mm standard length) fed on other lanternfish (chiefly L. hectoris). The diets of M. muelleri and L. hectoris overlapped substantially. Diet overlaps between D. danae and the former species was low, however, due to the large biomass of fish present in D. danae. The prey taxa consumed changed with time of year and predator size. Stomach fullness (feeding intensity) varied seasonally in all three species, but only M. muelleri showed significant diel differences in fullness. The synchronization of the size structure of the predator populations and their feeding intensity, with seasonal variations in preferred prey, is proposed as a mechanism whereby each species maximizes its share of the available food resources.  相似文献   
570.
The biochemical and energetic composition of body components of ten species of bathyal echinoids, and an asteroid, a holothuroid and a stalked crinoid were determined from individuals sampled from a variety of deep-water sites near the Bahamas (north Caribbean Sea) in October 1988. When compared with other studies of echinoderms, no geographic- or depth-related differences in biochemical or energetic composition were found. Body-wall tissues were composed primarily of skeletal material (mineral ash), but were comparatively high in organic material in the echinothuriid echinoids, and the asteroid and holothuroid. Gut tissues and pyloric cecae had high levels of lipid and protein, indicating their potential role in nutrient storage. Body-wall tissues were generally low in energy, but were highest in the echinoidsAraeosoma belli (7.7 kJ g–1 dry wt) andSperosoma antillense (8.0 kJ g–1 dry wt), the asteroidOphidiaster alexandri (8.9 kJ g–1 dry wt), and the holothuroidEostichopus regalis (13.1 kJ g–1 dry wt). Energy levels of gut and pyloric cecal tissues were two to three times higher than those of body-wall tissues. Total somatic tissue energy values varied greatly among species, ranging from 1.5 kJ in the echinoidAspidodiadema jacobyi to 142.1 kJ inE. regalis. As the bathyal echinoderms examined in this study occur in great abundance, they represent a significant reservoir of organic and inorganic materials and energy in deep-water benthic systems.  相似文献   
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