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51.
Evaluation of different algal species sensitivity to mercury and metolachlor by PAM-fluorometry. 总被引:6,自引:0,他引:6
In this study, the pulse-amplitude-modulation (PAM)-fluorometric method was used to evaluate the difference in the sensitivity to mercury (Hg) and metolachlor of six algal species: Ankistrodesmus falcatus, Selenastrum capricornutum, Chlorella vulgaris, Nannoplankton (PLS), Microcystis aeruginosa and Pediastrum biwae. We found that the fluorescence parameters (phiM, the maximal photosystem II (PSII) quantum yield, phi'M, the operational PSII quantum yield at steady state of electron transport, Q(P), the photochemical quenching value, and Q(N), the non-photochemical quenching value) were appropriate indicators for inhibitory effects of mercury but only phi'M and Q(N) were useful for metolachlor. The examined algal species showed very different levels of sensitivity to the effect of Hg and of metolachlor. The most sensitive species to Hg and metolachlor were respectively M. aeruginosa and A. falcatus, while the least sensitive were C. vulgaris and P. biwae. We interpreted these differences by the action mode of pollutants and by the different metabolism properties and morphological characteristics between algal species. These results related to fluorescence parameters may offer useful tool to be used in bioassay for different pollutants. Heterogeneous algal sensitivity to the same pollutant suggests the need to use a battery of species to evaluate the effects of mixtures of pollutants in aquatic systems. 相似文献
52.
53.
Soromon Kataoka Hideaki Sawai Hideto Yamada Nozomi Kanazawa Koji Koyama Gen Nishimura Mamoru Morikawa Noriaki Sakuragi Hisanori Minakami 《黑龙江环境通报》2004,24(1):45-49
Hypochondroplasia is an autosomal dominant skeletal dysplasia expressing postnatal onset of short stature with mild rhizomelic shortening of the limbs. This manifestation leads to restricted prenatal diagnosis of the disorder. We report here on a sporadic case of a hypochondroplastic baby, whose prenatal sonographic measurements were serially recorded from 19 weeks of gestation. Mild shortening of the limbs became manifest after 26 weeks of gestation. Biparietal diameter was within the normal range throughout gestation. Both parents were of average stature. A tentative diagnosis of a nonlethal short-limb skeletal dysplasia was made. At birth, the clinical manifestations of the neonate were not characteristic, but the radiographic features raised the possibility of hypochondroplasia. Molecular analyses revealed a C to G mutation at nucleotide 1659 of the fibroblast growth factor receptor 3 (FGFR3) gene, a common mutation in hypochondroplasia. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
54.
Sex mosaics in a male dimorphic ant Cardiocondyla kagutsuchi 总被引:1,自引:1,他引:0
Gynandromorphy, or the development of organisms with a combination of male and female morphological features, is common in
Hymenoptera. The underlying mechanism is likely associated with the sex-determination system, and studying this phenomenon
should lead to a deeper understanding of both embryonic development and sex determination. The reproductive capabilities of
gynandromorphs (hereafter, sex mosaics) remain unclear. We studied gynandromorphy in the Malaysian ant Cardiocondyla kagutsuchi, which has sex mosaics of queens (gynandromorphs; mosaic of queens and winged male) and workers (ergatandromorphs; mosaic
of worker and wingless ergatoid male). These sex mosaics were classified into seven morphological categories. Most individuals
had more male than female body areas. Behavioral observations revealed that sex mosaics behave more in accordance with the
“sex” of their brain than that of the reproductive organs (gaster). Relative DNA quantities showed that both female and male
regions contained haploid and diploid nuclei, irrespective of their phenotypic appearance, indicating that external appearance
did not reflect internal tissues. Nearly one third of the adults were sex mosaics and they were not infected with Wolbachia. Our results suggest that the production of sex mosaics in this species does not pose a substantial cost to colonies and
that the underlying causes are therefore not strongly selected against. 相似文献
55.
With the exception of several species, bumblebees are monandrous. We examined mating frequency in feral colonies of the introduced bumblebee Bombus terrestris in Japan. Using microsatellite markers, genotyping of sperm DNA stored in the spermatheca of nine queens detected multiple insemination paternities in one queen; the others were singly mated. The average effective paternity frequency estimated from the genotypes of queens and workers was 1.23; that estimated from the workers’ genotype alone was 2.12. These values were greater than those of laboratory-reared colonies in the native ranges of B. terrestris. The genotypes of one or two workers did not match those of their queens or showed paternities different from those of their nestmates; this may have arisen from either queen takeover or drifting of workers. These alien workers were responsible for the heterogeneous genotype distribution within each B. terrestris colony, resulting in higher estimates of paternity frequency than of insemination frequency. The high mating frequency of introduced B. terrestris may have occurred by artificial selection through mass breeding for commercialization. Moreover, polyandrous queens may be selectively advantageous, because reproduction by such queens is less likely to be disturbed by interspecific mating than that by monandrous queens. 相似文献
56.
Kameoka Hiroshi Ito Koji Ono Junko Banno Arisa Matsumura Chisato Haga Yuki Endo Kazuto Mizutani Satoshi Yabuki Yoshinori 《Journal of Material Cycles and Waste Management》2022,24(1):287-296
Journal of Material Cycles and Waste Management - Per- and polyfluoroalkyl substances (PFASs) are used in products, such as aqueous film-forming foam and fluorochemical surfactants, because of... 相似文献
57.
Ou-Sup Han Masaaki Yashima Toei Matsuda Hidenori Matsui Atsumi Miyake Terushige Ogawa 《Journal of Loss Prevention in the Process Industries》2000,13(6):449-457
The structure of flame propagating through lycopodium dust clouds has been investigated experimentally. Upward propagating laminar flames in a vertical duct of 1800 mm height and 150×150 mm square cross-section are observed, and the leading flame front is also visualized using by a high-speed video camera. Although the dust concentration decreases slightly along the height of duct, the leading flame edge propagates upwards at a constant velocity. The maximum upward propagating velocity is 0.50 m/s at a dust concentration of 170 g/m3. Behind the upward propagating flame, some downward propagating flames are also observed. Despite the employment of nearly equal sized particles and its good dispersability and flowability, the reaction zone in lycopodium particles cloud shows the double flame structure in which isolated individual burning particles (0.5–1.0 mm in diameter) and the ball-shaped flames (2–4 mm in diameter; the combustion time of 4–6 ms) surrounding several particles are included. The ball-shaped flame appears as a faint flame in which several luminous spots are distributed, and then it turns into a luminous flame before disappearance. In order to distinguish these ball-shaped flames from others with some exceptions for merged flames, they are defined as independent flames in this study. The flame thickness in a lycopodium dust flame is observed to be 20 mm, about several orders of magnitude higher than that of a premixed gaseous flame. From the microscopic visualization, it was found that the flame front propagating through lycopodium particles is discontinuous and not smooth. 相似文献
58.
This paper extrapolates future paths of genuine savings (GS) by using our integrated assessment model. The results with the base case (BC) indicate that both GS without population change (GS) and GS with population change (GSn) are almost positive in OECD countries in the twenty-first century (satisfying the necessary but insufficient condition for sustainability); those numbers are projected to be negative in 2100. Asia (ASIA), the Middle East and Africa (MEAF), the former Soviet Union and Eastern Europe (FSEE), and the world show upward trends for both values, showing negative signs in 2010 and positive signs after 2050 (in ASIA, MEAF, and the world) and in 2100 (in FSEE). The values in Latin America (LAMR) remain negative throughout. We examine additional following three cases: demand reduction (DR), carbon dioxide (CO2) emissions reduction (CR), and population reduction (PR). The GSn results compared to the BC indicate that (1) GSn in DR is similar to that of BC, (2) GSn in PR is slightly higher than that of BC, and (3) GSn in CR is unexpectedly lower than that of BC. This GSn reduction in the CR case derives from the fact that the term for calculating resource depletion (especially resource rent, which equals the difference between price and cost) in GS and GSn increased, leading to a greater term being subtracted from gross savings. The resource price increases with the marginal price of natural gas, given the energy-source shift in reducing CO2 emissions, from cheap coal to expensive natural gas. 相似文献
59.
Core self‐evaluations in Japan: relative effects on job satisfaction,life satisfaction,and happiness
Ronald F. Piccolo Timothy A. Judge Koji Takahashi Naotaka Watanabe Edwin A. Locke 《组织行为杂志》2005,26(8):965-984
The present study tested, in a non‐Western culture (Japan), the relative validity in predicting job satisfaction, life satisfaction, and happiness of core self‐evaluations (CSE), positive and negative affectivity (PA/NA), and the Neutral Objects Satisfaction Questionnaire (NOSQ). Consistent with previous results in primarily Western cultures, the four lower‐order traits that comprise CSE—self‐esteem, generalized self‐efficacy, locus of control, and neuroticism—indicated a higher‐order factor. While each lower‐order trait was itself related to the study's criteria, the CSE concept displayed in general, higher correlations with the dependent variables, and explained incremental variance in two of the study's three outcomes beyond PA, NA, and the NOSQ. These results indicate initial support for the generalizability of CSE in a culture that differs in many respects from Western cultures, and suggest that judgments of satisfaction and happiness in a non‐Western culture have a dispositional source. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
60.
"生态环卫"技术提供了共同解决两个关键水难题的办法:如何使世界缺乏用水和卫生设备的人数比例下降一半;如何解决湖泊、水库和内海的富营养化.氮和磷超标,主要来源于城市污水和农业肥料的流失.尿液和粪便(特别是尿液)含有氮和磷.一个新的人类废物管理办法,有可能使这些物质在农业领域循环. 相似文献