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201.
The concentrations of ambient air polycyclic aromatic hydrocarbons were measured in a farm area (Tunghai University Pastureland) between August 2001 and April 2002 in central Taiwan, Taichung. Particle-bound polycyclic aromatic hydrocarbons (PAHs) were collected on quartz filters, the collected sample was extracted with a dichloromethane (DCM)/n-hexane mixture (50/50, v/v) for 24 h, and then the extracts were subjected to gas chromatography-mass spectrometric analysis. The PM2.5 (fine particulate) and PM2.5-10 (coarse particulate) total PAHs concentrations at the Tunghai University Pastureland sampling site were found to be 180.62 ngm(-3) and 164.98 ngm(-3), respectively. In general, the concentrations of polycyclic aromatic hydrocarbons were higher in spring and winter than those of summer and autumn for either PM2.5 or PM2.5-10 in Pastureland in central Taiwan. Moreover, coarse particulates are the dominant species during the dust storm season (March and April) in central Taiwan. 相似文献
202.
Twenty-five volatile organic compounds (VOCs) up to C10 were measured using Carbotrap multibed thermal adsorption tubes during the morning and afternoon rush hours on four different days in all three traffic tunnels in Kaohsiung, Taiwan. A gas chromatograph (GC) equipped with a flame-ionization detector (FID) was then used to analyze the VOCs. The analytical results show that VOC concentrations increase with traffic flow rate, and emission profiles in the three tunnels are mostly in the range C2-C6. In addition to the traffic conditions and vehicle type, the pattern of emissions in each tunnel was also influenced by other factors, such as vehicle age, nearby pollution sources, and the spatial or temporal variation of VOCs in the urban atmosphere. The ozone formation potential (OFP) in each tunnel was assessed based on the maximum incremental reactivities of the organic species, demonstrating that OFP increases with traffic flow rate. Vehicle distribution influences the contributions of organic group to OFP in a tunnel. Meanwhile, when ranked in descending order of contribution to OFP in all tunnels, the organic groups followed the sequence olefins, aromatics, and paraffins. 相似文献
203.
204.
A case of in utero closure of the ductus arteriosus was detected by Doppler echocardio-graphy at 31 weeks of gestation. It presented as a non-hydropic distressed fetus with ultrasound detection of tricuspid regurgitation. Pulsed Doppler ultrasound showed markedly decreased blood flow through the tricuspid and pulmonary valves and absent blood flow at the ductus arteriosus. These, as well as the resultant increased right-to-left shunting across the foramen ovale, were reaffirmed by colour flow mapping. 相似文献
205.
Understanding the emission sources of volatile organic compounds (VOCs) is critical for air pollution mitigation. Continuous measurements of atmospheric VOCs were conducted from January to February in Hangzhou in 2021. The average measured concentration of total VOCs (TVOCs) was 38.2 ± 20.9 ppb, > 42% lower than that reported by previous studies at the urban center in Hangzhou. The VOC concentrations and proportions were similar between weekdays and weekends. During the long holidays of the Spring Festival in China, the concentrations of TVOCs were ∼50% lower than those during the regular days, but their profiles showed no significant difference (p > 0.05). Further, we deduced that aromatics and alkenes were the most crucial chemicals promoting the formation of O3 and secondary organic aerosol (SOA) in Hangzhou. According to interspecies correlations, combustion processes and solvent use were inferred as major VOC emission sources. This study provides implications for air quality improvements before and during the upcoming Asian Games that will be hosted in Hangzhou in 2022. 相似文献
206.
Hae Sang Jun Bong Oh Kim Yeon Chul Kim Ho Nam Chang Seong Ihl Woo 《Journal of Polymers and the Environment》1994,2(1):9-18
Copolyesters containing poly(ethylene terephthalate) (PET) and poly(-caprolactone) (PCL) were synthesized from PET and PCL homopolymers by transesterification reaction at 270°C in the presence of catalyst. The copolyesters were characterized by13C-NMR and differential scanning calorimetry (DSC). The degradation behavior of PCL byPseudomonas sp. lipase in buffer solution (pH 7) and tetrahydrofuran (THF) was investigated by gel permeation chromatography (GPC) and1H-NMR. From these experiments, it was found thatPseudomonas sp. lipase acted endoenzymatically on PCL. Using this lipase, degradation tests for PET/PCL copolyesters whose PCL content was below 50% by weight were also performed in buffer solution (pH 7). However, evenPseudomonas sp. lipase with high degradation activity on PCL did not easily degrade the PCL unit in PET/PCL copolyesters. 相似文献
207.
Evolutionary theory has been likened to a “universal acid” (Dennett 1995) that eats its way into more and more areas of science. Recently, developmental biology has been infused by evolutionary
concepts and perspectives, and a new field of research—evolutionary developmental biology—has been created and is often called
EvoDevo for short. However, this is not the first attempt to make a synthesis between these two areas of biology. In contrast,
beginning right after the publication of Darwin’s Origin in 1859, Ernst Haeckel formulated his biogenetic law in 1872, famously stating that ontogeny recapitulates phylogeny. Haeckel
was in his turn influenced by pre-Darwinian thinkers such as Karl Ernst von Baer, who had noted that earlier developmental
stages show similarities not seen in the adults. In this review, written for an audience of non-specialists, we first give
an overview of the history of EvoDevo, especially the tradition emanating from Haeckel and other comparative embryologists
and morphologists, which has often been neglected in discussions about the history of EvoDevo and evolutionary biology. Here
we emphasize contributions from Russian and German scientists to compensate for the Anglo-American bias in the literature.
In Germany, the direct influence of Ernst Haeckel was felt particularly in Jena, where he spent his entire career as a professor,
and we give an overview of the “Jena school” of evolutionary morphology, with protagonists such as Oscar Hertwig, Ludwig Plate,
and Victor Franz, who all developed ideas that we would nowadays think of as belonging to EvoDevo. Franz ideas about “biometabolic
modi” are similar to those of a Russian comparative morphologist that visited Jena repeatedly, A. N. Sewertzoff, who made
important contributions to what we now call heterochrony research—heterochrony meaning changes in the relative timing of developmental
events. His student I. I. Schmalhausen became an important contributor to the synthetic theory of evolution in Russia and
is only partly known outside of the Russian-reading world because only one of his many books was translated into English early
on. He made many important contributions to evolutionary theory and we point out the important parallels between Schmalhausen’s
ideas (stabilizing selection, autonomization) and C. H. Waddington’s (canalization, genetic assimilation). This is one of
the many parallels that have contributed to an increased appreciation of the internationality of progress in evolutionary
thinking in the first half of the twentieth century. A direct link between German and Russian evolutionary biology is provided
by N. V. Timoféeff-Ressovsky, whose work on, e.g., fly genetics in Berlin is a crucial part of the history of evo-devo. To
emphasize the international nature of heterochrony research as predecessor to the modern era of EvoDevo, we include Sir G.
R. de Beer’s work in the UK. This historical part is followed by a short review of the discovery and importance of homeobox
genes and of some of the major concepts that form the core of modern EvoDevo, such as modularity, constraints, and evolutionary
novelties. Major trends in contemporary EvoDevo are then outlined, such as increased use of genomics and molecular genetics,
computational and bioinformatics approaches, ecological developmental biology (eco-devo), and phylogenetically informed comparative
embryology. Based on our survey, we end the review with an outlook on future trends and important issues in EvoDevo. 相似文献
208.
James B. McClintock Robert A. Angus Christina Ho Charles D. Amsler Bill J. Baker 《Marine Biology》2008,154(6):1077-1084
The circumpolar sea star Odontaster validus is ubiquitous in the nearshore marine benthos of Antarctica. Despite its ecological importance, little is known of its behavioral
interactions with other common sympatric sea stars. To examine these interactions we employed time-lapse video analyses conducted
in a large laboratory tank (1.8 m diameter circular tank, 1,629 L). In each experimental trial, 34 adult O. validus were placed in a tight circular grouping on one side of the tank, and one adult individual of one of three common sympatric
species of predatory sea star (Labidiaster annulatus, Diplasterias brandti, or Perknaster aurorae) was placed on the opposite side of the tank. Digital images of sea star movements were then captured at one min intervals
over a 24 h period and aspects of sea star movements subsequently analyzed. Each 24 h treatment was replicated three times,
as was a control treatment consisting only of O. validus. O. validus had significantly elevated levels of activity in the presence of P. aurorae when compared with the other two sea stars (potential chemically mediated response), and displayed a distinct “flight response”
(change in direction and twofold to sixfold increase of speed) upon tactile contact with this species. Moreover, an “alarm
response” was detected when individuals of O. validus that encountered a fleeing conspecific also fled the vicinity. In contrast, our results indicated that O. validus displays virtually no chemical or tactile behavioral responses to the large multi-armed L. annulatus and only weak tactile responses to D. brandti. 相似文献
209.
Many species base their choice of mates on multiple signals which provide them with different kinds of information. Choosers
may assess the signals together to evaluate the overall quality of potential mates, but individuals often pay attention to
different signals in different contexts. In Rhinogobius brunneus, a fish displaying exclusive male parental care, females generally prefer males showing larger first dorsal fins (FDF) and
more active courtship displays as mates. Females choosing a mate usually initially assess the FDF and later utilize courtship
for the final decision. In our experiments, females with different hunger states used different signals when selecting mates.
Females in both hunger states preferred males with larger FDF in the first stage. In the second stage, well-fed females showed
highly repeatable choice, whereas poorly fed females responded only to variation in the courtship activity of males. The males
preferred by poorly fed females exhibited significantly higher offspring survival than nonpreferred males. Under conditions
of food shortage, males allocate more energy to future reproduction at the expense of the present brood, and females may prioritize
signals predictive of offspring survivorship over signals reflecting other aspects in male quality to minimize the losses
in direct benefits. We conclude that R. brunneus females may employ information from both signals but dynamically adjust their prioritization of each signal to current conditions
to ensure the choice that is currently most adaptive. 相似文献
210.
Sidharthan M Viswanadh GS Kim KH Kim HJ Shin HW 《Journal of environmental biology / Academy of Environmental Biology, India》2007,28(2):173-176
In recent years, industrial pollutants and the mountain forest fire ashes released into seawater cause damage to the marine environment, mainly it reduces the algal productivity in the inter tidal region. To get recover from the stress due to pollutants and to increase the growth and development of biofouling algae (benthic organisms), Ecklonia cava extract was investigated for its biofouling attracting efficiency. Bioactive guided fractions of E. cava extract derived from column chromatography were tested against spore attachment of a fouling alga, Ulva pertusa. Fraction B showed increased spore attachment rate with a maximum of 92 +/- 5%. This fraction was further analysed on HPLC, GC-Mass and NMR, deduced as pentadecanoic acid. 相似文献