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71.
J.P.W. Rivers 《Disasters》1982,6(4):256-267
In general, little attention has been given to differential survival between the sexes in disasters. Consideration of physiological differences between males and females would suggest that, all things being equal, morbidity and mortality after disaster, particularly where food shortage is involved, should indicate an excess male mortality. Such statistics as exist in disasters, as in chronic underdevelopment, show that it is females and especially girl children who are at highest risk. The basis of this lies in sex discrimination which is implicit in most social systems.  相似文献   
72.
In 1996–1999, different mortality factors of pollen beetle larvae were investigated in twenty six rape fields in the northern part of Switzerland which had either a wild flower strip or an extensively managed meadow adjacent to the long side of the field. At 3 and 30 m into the crop from the conservation strip, total mortality, mortality from predators, parasitoids and unspecified factors were measured. Total pollen beetle larval mortality was 66–96%. Mortality caused by predators was 16–27% and there was no significant difference between mortality at 3 m and that 30 m from the extensively managed meadows. However, in fields with wild flower strips adjacent to them, the percentage mortality from predators was significantly greater at 30 m than at 3 m. The range of parasitism of pollen beetle larvae was 0–54% and was on average greater at 3 m than at 30 m. In fields with wild flower strips, the percentage parasitism with Tersilochus heterocerus was significantly higher than in fields with extensively managed meadows. However, mortality from all parasitoids was only 1–2% and there was no significant difference between 3 and 30 m. The effect of parasitoids on pollen beetle mortality was masked by the high unspecified mortality and the mortality from predators. The unspecified mortality was 46–72% and was significantly greater in 1998 and 1999 than in 1996 and 1997. These differences are probably because of meteorological factors (wet in 1999 and dry in 1998). The possible influences of the two types of conservation strips on pollen beetle larval density were investigated. The results show that in fields with adjacent wild flower strips, the pollen beetle larvae were more evenly distributed (but not significantly so) than in fields with extensively managed meadows where larval density decreases faster from the edge into the rape field.  相似文献   
73.
采用不同的光照强度,异、同地亲鲍,投放受精卵和投放担轮幼虫等3种方法进行育苗试验,结果表明,在九孔鲍人工苗种生产中,采取1 000~1500 lx的光照强度,用异地亲鲍繁育,投放担轮幼虫等方法进行育苗,可以预防或减少"脱板症"的发生.本文还就相关问题进行了探讨.  相似文献   
74.
Mortality of animals on roads is a critical threat to many wildlife populations and is poised to increase strongly because of ongoing and planned road construction. If these new roads cannot be avoided, effective mitigation measures will be necessary to stop biodiversity decline. Fencing along roads effectively reduces roadkill and is often used in combination with wildlife passages. Because fencing the entire road is not always possible due to financial constraints, high-frequency roadkill areas are often identified to inform the placement of fencing. We devised an adaptive fence-implementation plan to prioritize road sections for fencing. In this framework, areas along roads of high, moderate, and low levels of animal mortality (respectively, roadkill hotspots, warmspots, and coldspots) are identified at multiple scales (i.e., in circles of different diameters [200–2000 m] in which mortality frequency is measured). Fence deployment is based on the relationship between the amount of fencing being added to the road, starting with the strongest roadkill hotspots, and potential reduction in road mortality (displayed in mortality-reduction graphs). We applied our approach to empirical and simulated spatial patterns of wildlife–vehicle collisions. The scale used for analysis affected the number and spatial extent of roadkill hot-, warm-, and coldspots. At fine scales (e.g., 200 m), more hotspots were identified than at coarse scales (e.g., 2000 m), but combined the fine-scale hotspots covered less road and less fencing was needed to reduce road mortality. However, many short fences may be less effective in practice due to a fence-end effect (i.e., animals moving around the fence more easily), resulting in a trade-off between few long and many short fences, which we call the FLOMS (few-long-or-many-short) fences trade-off. Thresholds in the mortality-reduction graphs occurred for some roadkill patterns, but not for others. Thresholds may be useful to consider when determining road-mitigation targets. The existence of thresholds at multiple scales and the FLOMS trade-off have important implications for biodiversity conservation.  相似文献   
75.
Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) is a serious pest of corn in several American countries. It is mainly controlled with synthetic insecticides. The objectives of this study were to evaluate the effects of the natural products, neem oil and pyroligneous extract, and the synthetic insecticide, lufenuron, at 2.50mL water (0.25 %) on the mortality of 2-, 4- and 6-day-old caterpillars of S. frugiperda, and their selectivities against fourth instar larvae of Eriopis connnexa Germar (Coleoptera: Coccinellidae). Four- and 6-day-old S. frugiperda caterpillars showed higher mortality after exposure to neem oil (83.33 ± 0.83 and 89.58 ± 0.90 %, respectively) and lufenuron (95.83 ± 0.96 and 85.41 ± 0.83 %), compared to pyroligneous extract (68.75 ± 0.69 and 31.25 ± 0.31 %). The deleterious effect of pyroligneous extract was higher in 2- (83.33 ± 0.83 % mortality) and 4-day-old (68.75 ± 0.69 %) S. frugiperda caterpillars than in 6-day-old caterpillars (31.25 ± 0.31 %). Larval mortality of the predator E. connexa was lower with neem oil and pyroligneous extract (25.00 ± 0.33 %) than with lufenuron (91.66 ± 1.22 %). Neem oil is thus recommended for control of S. frugiperda because of its high toxicity, combined with its relatively low toxicity to larvae of the natural enemy E. connexa.  相似文献   
76.
探讨不同臭氧度量指标对我国人群总死亡风险的影响.基于中国知网、万方数据库、维普中文服务平台、 Web of Science和PubMed数据库,检索了建库至2020年12月底发表的相关时间序列研究和病例交叉研究,最终纳入22项合格研究.按照臭氧每日1 h最大浓度(O3-M1h)、每日8 h最大平均浓度(O3-M8h)和每日24 h平均浓度(O3-24h)分别进行Meta分析.结果表明,O3-M1h指标(RR#, 1.005 2; 95%CI, 1.003 1~1.007 3)与人群总死亡风险增加的关联更加密切,O3-24h指标(RR#, 1.003 6; 95%CI, 1.002 5~1.004 8)和O3-M8h指标(RR#, 1.003 1; 95%CI, 1.002 2~1.004 1)关联较弱. 3类指标的亚组分析表明,冷季臭氧的总死亡风险更高,老年人(≥65岁)更容易受臭氧污染的影响,且北方地区总死亡风险高于南方地区.  相似文献   
77.
Globally, policies aiming for conservation of species, free-flowing rivers, and promotion of hydroelectricity as renewable energy and as a means to decarbonize energy systems generate trade-offs between protecting freshwater fauna and development of hydropower. Hydroelectric turbines put fish at risk of severe injury during passage. Therefore, comprehensive, reliable analyses of turbine-induced fish mortality are pivotal to support an informed debate on the sustainability of hydropower (i.e., how much a society is willing to pay in terms of costs incurred on rivers and their biota). We compiled and examined a comprehensive, global data set of turbine fish-mortality assessments involving >275,000 individual fish of 75 species to estimate mortality across turbine types and fish species. Average fish mortality from hydroelectric turbines was 22.3% (95% CI 17.5–26.7%) when accounting for common uncertainties related to empirical estimates (e.g., handling- or catch-related effects). Mortality estimates were highly variable among and within different turbine types, study methods, and taxa. Technical configurations of hydroelectric turbines that successfully reduce fish mortality and fish-protective hydropower operation as a global standard could balance the need for renewable energy with protection of fish biodiversity.  相似文献   
78.
The interactions between cod (Gadus morhua), herring (Clupea harengus) and sprat (Sprattus sprattus) in the Central Baltic Sea were examined with a simple dynamic model, an alternative to more complicated and data-demanding multispecies and ecosystem models. The main aims of the study were to compare the effect of alternative structures on the model output and examine the control relationships in the fish assemblage under different environmental conditions. The effect of environmental conditions was modelled using a stock-recruitment equation for cod incorporating an environmental index. The model output was especially sensitive to the functional response in predation by cod on herring and sprat. The type II functional response led to a collapse of the clupeid stocks when cod was abundant, while the type III response produced more realistic stock dynamics. According to the simulations, an abundant cod stock was able to keep the sprat stock at a low level, while the herring stock was less affected and benefited from the decreased density of sprat. Simulation of different fishing scenarios indicated that reducing fishing mortality to the level currently advised by ICES would allow the recovery of the cod stock even in unfavourable environmental conditions.  相似文献   
79.
80.
为了评估PM2.5排放导致女性生殖系统癌症的风险以及城乡差异,以卵巢癌为例,分析了中国东部地区2000~2011年期间PM2.5和卵巢癌发病率和死亡率的相关关系,并估算了PM2.5排放导致卵巢癌发病率和死亡率升高的风险.结果表明,城市地区卵巢癌发病率和死亡率显著高于农村,在城市地区,PM2.5与卵巢癌发病率显著相关,PM2.5年平均浓度每上升10μg/m3,城市地区卵巢癌发病率上升的相对风险为9.3%(相对于PM2.5年平均浓度为35μg/m3时),每十万人口升高0.51人.  相似文献   
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