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121.
This paper reports on a study which explored the possible relationship between road traffic noisescape and urban form in Hong Kong. A total of 212 residential complexes from 11 contrasting urban forms were sampled, and their noise levels assessed both at dwelling and neighbourhood scales by noise mapping. Its findings indicate that residential complexes with different urban forms have significantly different noisescape attributes. There is a strong correlation between the noise characteristics and morphological indicators at the dwelling scale. A less obstreperous noisescape is associated with urban forms with lower road and building densities, and with building arrangements which provide self-noise screening. These findings suggest that urban form is an influential determinant of the noisescape in the urban environment, and they point to the need to rethink the conventional approach to managing the urban acoustic environment.  相似文献   
122.
In this paper, the occupational accidents and their effects on people are modeled. The basis of energy flow/barrier analysis is used to define an accident as the impact of a hazardous agent on a target, as a result of failure of control and protective barriers. This definition is enhanced to include serial and parallel barriers and to distinguish energy barriers from target barriers. The barrier attributes are defined and used to create a quantitative scenario-building model. The probability and severity of various accidents are estimated, by studying barrier reliability and efficiency. This approach is used to develop and simulate accident scenarios and to calculate their consequences. This model can be used in complex systems for analyzing the risk and estimating the importance of barriers.  相似文献   
123.
In addition to the usual fixed costs, we introduce variable costs in a community's effort to cooperate in extracting from a common pool resource. Using a standard supervision mechanism, these variable costs are shown to be an increasing function of individual members' incentives to default. The model explains why we frequently observe communities that all cooperate and have relatively similar resource endowments, and yet achieve very different levels of extraction.  相似文献   
124.
We report two male fetuses born to a healthy unrelated couple, with agenesis of the corpus callosum identified on detailed 20-week ultrasound scans and confirmed by in-utero MRI. Whole-genome sequencing identified a likely pathogenic missense variant in the CLCN4 gene, establishing this as the causative gene in the family. Pathogenic variants in the CLCN4 gene cause a neurodevelopmental disorder (also called Raynaud-Claes syndrome) inherited in an X-linked pattern. The disorder is characterised by developmental delay, intellectual disability, autism spectrum disorder, epilepsy, mental health conditions, and significant feeding difficulties, predominantly, but not exclusively, affecting males. This is the first report of a prenatal phenotype associated with variants in the CLCN4 gene. The diagnosis of the CLCN4-related neurodevelopmental disorder in this family allowed accurate genetic counseling and discussion of reproductive choices. This leaves uncertainty about the possibility of a postnatal neurodevelopmental phenotype in heterozygous females, which we discuss.  相似文献   
125.
<正>The Three Gorges Dam project(TGDP),with a total static investment of 95.46 billion RMB(US$10.97 billion)based on the 1993 price level,commenced in 1994 and was completed in 2012.The creation of the Three Gorges Reservoir following the completion of the TGDP had brought about significant changes to the Three Gorges Reservoir Region(TGRR),stretching from the town of Sandouping in Hubei Province to the Jiangjin District of Chongqing Municipality.The TGDP has led to progressive urbanization and industrialization of the TGRR,accompanied by increased shipping activities,greater  相似文献   
126.
We tested if nesting habits influence ant feeding preferences and predatory behavior in the monophyletic genus Pseudomyrmex (Pseudomyrmecinae) which comprises terrestrial and arboreal species, and, among the latter, plant-ants which are obligate inhabitants of myrmecophytes (i.e., plants sheltering so-called plant-ants in hollow structures). A cafeteria experiment revealed that the diet of ground-nesting Pseudomyrmex consists mostly of prey and that of arboreal species consists mostly of sugary substances, whereas the plant-ants discarded all the food we provided. Workers forage solitarily, detecting prey from a distance thanks to their hypertrophied eyes. Approach is followed by antennal contact, seizure, and the manipulation of the prey to sting it under its thorax (next to the ventral nerve cord). Arboreal species were not more efficient at capturing prey than were ground-nesting species. A large worker size favors prey capture. Workers from ground- and arboreal-nesting species show several uncommon behavioral traits, each known in different ant genera from different subfamilies: leaping abilities, the use of surface tension strengths to transport liquids, short-range recruitment followed by conflicts between nestmates, the consumption of the prey’s hemolymph, and the retrieval of entire prey or pieces of prey after having cut it up. Yet, we never noted group ambushing. We also confirmed that Pseudomyrmex plant-ants live in a kind of food autarky as they feed only on rewards produced by their host myrmecophyte, or on honeydew produced by the hemipterans they attend and possibly on the fungi they cultivate.  相似文献   
127.
Patoine A  Leavitt PR 《Ecology》2006,87(7):1710-1721
Synchronous fluctuations in limnological variables among lakes may signal that large-scale environmental factors regulate lake ecosystem structure, yet most estimates of temporal coherence are based on short (<25 yr) time series, and little is known of how synchrony varies among biological taxa or of the causes of temporal coherence. Here we used time series of 13 fossil pigments from diverse algal groups in seven lakes of the climatically sensitive Northern Great Plains to demonstrate that algal synchrony (S) during the 20th century arose mainly from interdecadal increases in algal abundance rather than from interannual coherence. Synchrony of time series differed greatly among algal taxonomic groups (S = 0.0-0.75) and was not usually spatially structured, but decreased 83% following removal of long-term trends using exponential models or first-difference calculations. Overall, coherence was greatest for labile compounds chl a (S = 0.53) and fucoxanthin (S = 0.75), possibly reflecting the influence of postdepositional degradation processes on fossil time series. However, analysis of chemically stable pigments also indicated that synchrony was great for cryptophytes (as alloxanthin, S = 0.42) and diatoms (diatoxanthin, S = 0.37), taxa that bloom in spring. In contrast, synchrony of total algal abundance was low (beta-carotene, pheophytin a, S < 0.10), reflecting low interannual coherence of summer taxa including colonial cyanobacteria and chlorophytes. Unexpectedly, past variations in climate, resource use, and urbanization explained >85% of algal variation in individual lakes, but only 35% of synchronous algal fluctuations, suggesting that the factors controlling algal synchrony differ from those regulating algal abundance.  相似文献   
128.
The geographical distribution of hexabromocyclododecane (HBCD) was investigated through analysis of muscle tissue of skipjack tuna (Katsuwonus pelamis) collected from offshore waters of Asia-Pacific region (Japan, Taiwan, Philippines, Indonesia, Seychelles, Brazil, Japan Sea, East China Sea, South China Sea, Indian Ocean and North Pacific Ocean). HBCD was detected in almost all samples analyzed (<0.1 to 45 ng/g lipid weight basis), indicating widespread presence of this compound in the marine environment. Elevated concentrations of HBCD were found in skipjack tuna from areas around Japan, which have the larger modern industrial/urban societies, and implicated these areas as primary regional sources. All three individual HBCD isomers (alpha-, gamma- and beta-HBCD) were detected in almost all samples; the percentage contribution of the alpha-isomer to total HBCD increased with increasing latitude. The estimated empirical 1/2 distance for alpha-HBCD was 8500 km, which is one of the highest atmospheric transportability among various halogenated persistent organic pollutants (POPs).  相似文献   
129.
Sediments from two rivers in China, the Haihe and Dagu Rivers, were examined for estrogenic activity using an estrogen receptor (ER)-mediated in vitro bioassay system. ER-active compounds were isolated from sediments by Soxhlet extraction, and the crude extracts were fractionated using a florisil column into three fractions. The estrogenic activity of each extract was detected by measuring luciferase activity in the human breast cancer cell line MCF-7 transfected with a luciferase receptor gene. Significant estrogenic activity was observed in each total extract. The 17beta-estradiol equivalents (E2-EQs) ranged from 8.24 to 95.28 ng E2 g(-1) dw. As a result, the relative estrogenic potencies of three fractions in this study descended in the order of Fraction 3>Fraction 2>Fraction 1. The results of the bioassay analysis indicated the heavy pollution status of these sites with estrogenic contaminants. In this study, five selected chemicals, the natural estrogens 17beta-estradiol (E2) and estrone (E1), and the xeno-estrogens 4-octylphenol (OP), 4-nonylphenol (NP), and Bisphenol A (BPA) were also analyzed using the in vitro bioassay. The estrogenic activity of these chemicals were E2>E1>NP>OP>BPA.  相似文献   
130.
Since 1985, monitoring activities have been conducted in a networkof 43 lakes comprising the Québec portion of the Long-Range Transport of Airborne Pollutants (LRTAP) program. The results to date indicate that Québec lakes generally are responding positively to the generalized decline in precipitation sulfate (SO4 2-), with 40 of the 43 lakes now showing steep declines in SO4 2- concentrations. The drop in SO4 2- was associated with a significant decrease in Ca2+ concentrations in 77% of the lakes (67% for Mg2+ concentrations). Overall, the acid-neutralizing capacity was increasing in 19 lakes and decreasing only in three, while 21 lakes showed no temporal trends. Compared with previous trend studies of the LRTAP-Québec network for the period of 1985–1993, the longer period (1985–1999) shows a clear improvement, with the proportion of lakes that were acidifying changing from 24 to 7% and with the proportion of lakes that were recovering changing from 16 to 35%. These observations suggest that the recent drop in SO4 2- deposition in the northeastern U.S. and eastern Canada was significant enough to allow chemical recovery for a significant proportion of Québec lakes.  相似文献   
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