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971.
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973.
溢油追踪报警器可行性研究 总被引:2,自引:0,他引:2
通过对专门设计的漂浮物在海洋中运动规律的分析,研究用来跟踪海上溢油漂移路线的可行性,从而,为溢油应急指挥中心的决策提供技术支持手段。 相似文献
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975.
Francesco Ciliberti Job de HaanGerard de Groot Pierpaolo Pontrandolfo 《Journal of Cleaner Production》2011,19(8):885-894
The benefits of corporate social responsibility (CSR) affect the entire supply chains a firm participates in. However, not every firm is in a position to force the implementation of CSR in its supply chains as some, especially small and medium-sized enterprises (SMEs), lack the necessary power. Chain directors can implement it acting as a principal, whereas the other chain members can act as agents.In the principal-agent framework, two main problems occur due to information asymmetry: adverse selection and moral hazard. This paper examines how a code of conduct (i.e. Social Accountability 8000) can help address the principal-agent problem, for SMEs, between chain directors and partners. The research method involves four case studies on CSR practices as implemented by Italian and Dutch SMEs within their supply chains. 相似文献
976.
In this article, we review the virology, pathology, epidemiology and clinical spectrum of intrauterine human parvovirus B19 (B19V) infection, including intrauterine fetal death, non-immune hydrops fetalis, thrombocytopenia and neurological manifestations such as pediatric stroke and perivascular calcifications. In addition, we discuss the new insights into the neurodevelopmental outcome of intrauterine B19V infection. Current diagnosis and management of B19V infection is summarized, including a diagnostic and follow-up flowchart for practical clinical use. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
977.
Ji?í Dole?al Zuzana MaškováJan Lepš Daniela SteinbachováFrancesco de Bello Jitka KlimešováOliver Tackenberg František ZemekJan Květ 《Agriculture, ecosystems & environment》2011,145(1):10-28
Oligotrophic mountain meadows are threatened biodiversity hotspots throughout Europe. The traditional summer hay-making followed by autumn grazing is no longer economic and question is whether alternative managements can maintain both plant species and functional diversity typical of these habitats. In the Bohemian Forest Mts., we applied three treatments (mowing once a year - i.e., cutting and removing the biomass, mulching once a year - cutting and leaving the crushed biomass to decompose in situ, fallowing - no cutting) in order to assess temporal changes in meadow vegetation, plant trait composition and biomass production in a 13-year experiment. We recorded for each species twenty-five traits as to be most informative of plant strategies related to growth, resource acquisition and carbon-water economy. We compared different components of trait composition (community averages that mostly reflect traits of dominant species vs. the Rao index of functional diversity that reflects trait dissimilarity among species) and their impact on biomass production. We show that mulching promotes species and functional diversity by facilitating heliophilous forbs and legumes with more acquisitive strategies in resource use and release, e.g., higher foliar N and P content. This occurs at the expense of tall grasses (with resource-retentive strategies, e.g., high leaf dry matter content) which dominate the mown and fallow plots. The divergence in most quantitative traits indicates that niche complementarity is the dominant assembly process in mulched plots, which can prevent competitive exclusion and enable species coexistence. The divergent development was detected only after 5-6 years. This slow floristic and functional response is caused by acidity of soil and severe mountain climate that preclude rapid responses of vegetation to land-use changes. We conclude that mulching represents a good compromise maintaining both plant species and functional diversity as well as a relatively high biomass production. Mowing without grazing leads to gradual nutrient loss and thus reduces the productivity and diversity in these oligotrophic ecosystems. Fallowing causes gradual loss in diversity by increased grass competition and litter accumulation. 相似文献
978.
Marta Horta de Sousa Vergílio Helena Maria Gregório Pina Calado 《Journal of Environmental Planning and Management》2015,58(6):1015-1033
The biophysical features of small islands (SI) distinguish them from other territories; isolation, small size and several anthropogenic pressures reduce the resilience of ecosystems and increase their vulnerability to global changes. Many SI have a shortage of infrastructures, institutions and technical/financial resources that hinder planning and require different integrated solutions. In Portugal, the National Ecological Reserve (NER) is legally binding for spatial planning instruments. It aims to defend natural values and areas of ecological value, or sensibility, or susceptible to natural hazards. However, the criteria for the design of NER are strictly set for mainland territory, not taking into account specific features of small islands. A case study of the Azores Archipelago is used to demonstrate that spatial planning instruments should be adapted to island contexts. Such adaptation will increase the effectiveness of their implementation in relation to the protection of natural resources, stability of biophysical structures and prevention of natural hazards. Observing the main differences between mainland and the Azores Archipelago it is possible to define a methodological transposition of the NER aims and goals into an island context. This approach is an answer to the constraints in effective adaptation of spatial planning instruments for islands. 相似文献
979.
A case of early diagnosis at 13 weeks' gestational age of Meckel–Gruber syndrome by ultrasound is reported in a patient with a 25 percent recurrence risk. The usefulness of genetic counselling and aimed echographic examination is discussed. 相似文献
980.
We describe a case in which a trisomic 22 placenta could be the cause of severe growth retardation in a chromosomally normal female fetus. At amniocentesis a mosaic 46,XX/ 47,XX, +22 was observed in amniotic fluid specimens sampled on two different occasions, while fetal blood from a diagnostic cordocentesis revealed a normal chromosome constitution. Postnatal studies showed the consistent presence of trisomic 22 cells in the placenta, while only normal metaphases were found in amnion, blood, and fibroblast cultures. 相似文献