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51.
Hormonal responses of broiler chickens exposed to crude petroleum flame and fumes at varying distances over a period of 16 h daily were evaluated for 56 days in a poultry house. The burning of crude petroleum was simulated in a designed burner. The measured distances were 4, 8, or 12 m from the flame point. The experimental design was a two-factor factorial in a completely randomized design (CRD) with factor A as distance from the crude petroleum flame and factor B was the age of birds in weeks. One hundred and eighty Anak day-old broiler chickens were divided into four groups of 45 birds each, replicated thrice at 15 birds per replicate. Control birds were located in a separate poultry building without the flame treatment. Gaseous emissions from the burning crude oil were monitored. Proprietary broiler starter and finisher diets were fed ad libitum. Blood samples were taken at the fourth and eighth week for hormone radioimmunoassay from each treatment. The hormones assayed were growth hormone (GH), thyroxine (T4,), and adrenaline. Results indicated that treatments did not significantly alter hormonal levels. The age of birds significantly affected the levels of all three hormones measured.  相似文献   
52.
Heavy metal(Cu, Mn, Zn, Pb, and Cd) concentrations were measured in the leaves of Sabina chinensis and Platycladus orientalis collected from urban, suburban, and rural sites in Tianjin, China. Photosynthetic pigment contents, reactive oxygen species content, malondialdehyde(MDA) content and antioxidant enzyme activity were investigated, providing physiological response parameters. Our comparison of the sites revealed that urbanization significantly influenced the heavy metal concentrations in bo...  相似文献   
53.
Great attention should be paid to the possible impacts of various nanoparticles on aquatic organism. Freshwater diatoms are essential components of phytoplankton and play a critical role in bioassessment of nanoparticle exposure in the environment. In this study, cell growth was inhibited by TiO2-NPs and MWCNTs, the 24?h EC50 values of TiO2-NPs and MWCNTs to Nitzschia frustulum were 20.75 and 24.64?mg?L?1, respectively. Significant decreases of Chl a content after TiO2-NPs exposures were detected and the Chl a content of N. frustulum was obviously increased by MWCNTs treatment at lower concentration. The ROS was detected in N. frustulum after TiO2-NPs and MWCNTs exposures. The MDA content was significantly induced by TiO2-NPs at lower concentrations of 24 and 48?h exposure; meanwhile, it increased at all tested concentrations at 24?h MWCNTs exposure. The SOD enzyme was induced by 72 and 96?h TiO2-NPs exposure, and increased by MWCNTs treatment at 96?h in N. frustulum. Scanning electron microscopy results revealed that N. frustulum had obvious cell deformation after TiO2-NPs treatment. The result showed that the physiological and biochemical response mechanisms after NPs exposure of diatom were species-specific, and in relation to the exposure concentration and time.  相似文献   
54.
It is important to select suitable organisms to adapt the requirement of di erent environment monitoring purposes. Following our previous study, the behavioral responses of Daphnia magna and Japanese madaka (Oryzias latipes) were investigated and compared under flow-through conditions in an on-line biomonitoring system. The results showed that both D. magna and Japanese madaka had similar biological clock, but the circadian rhythms of Japanese madaka was more clearly recorded than that of D. magna. And the sensitivity of D. magna was about two orders of magnitudes higher than that of Japanese madaka in di erent types of toxic chemicals (dichlorovos, deltamethrin and cadmium chloride). However, when both animals were used in an on-line biomonitoring system, the life span of D. magna was less than 7 days and Japanese madaka could last for more than one month without feeding. Therefore, D. magna was proposed to be a more sensitive bioindicator and was suitable for short term monitoring the pollution events at concentration level closing to the water quality standard, while Japanese madaka was more suitable for the long-term monitoring for accidental discharges.  相似文献   
55.
Objective: The goal of this study was to evaluate how well an in-laboratory rollover crash test methodology that constrains vehicle motion can reproduce the dynamics of unconstrained full-scale steering-induced rollover crash tests in sand.

Methods: Data from previously-published unconstrained steering-induced rollover crash tests using a full-size pickup and mid-sized sedan were analyzed to determine vehicle-to-ground impact conditions and kinematic response of the vehicles throughout the tests. Then, a pair of replicate vehicles were prepared to match the inertial properties of the steering-induced test vehicles and configured to record dynamic roof structure deformations and kinematic response.

Results: Both vehicles experienced greater increases in roll-axis angular velocities in the unconstrained tests than in the constrained tests; however, the increases that occurred during the trailing side roof interaction were nearly identical between tests for both vehicles. Both vehicles experienced linear accelerations in the constrained tests that were similar to those in the unconstrained tests, but the pickup, in particular, had accelerations that were matched in magnitude, timing, and duration very closely between the two test types. Deformations in the truck test were higher in the constrained than the unconstrained, and deformations in the sedan were greater in the unconstrained than the constrained as a result of constraints of the test fixture, and differences in impact velocity for the trailing side.

Conclusions: The results of the current study suggest that in-laboratory rollover tests can be used to simulate the injury-causing portions of unconstrained rollover crashes. To date, such a demonstration has not yet been published in the open literature. This study did, however, show that road surface can affect vehicle response in a way that may not be able to be mimicked in the laboratory. Lastly, this study showed that configuring the in-laboratory tests to match the leading-side touchdown conditions could result in differences in the trailing side impact conditions.  相似文献   
56.
快速发展的城市化和工业化引起近地层臭氧浓度不断升高,对城市绿化植物具有很大的毒性伤害。选择城市常见的景观植物万寿菊、矮牵牛及圆叶牵牛为供试植物,利用开顶式气室,研究了不同植物臭氧伤害症状及其生理响应机制的差异。结果表明:1)臭氧暴露后,供试植物叶片均出现了不同程度的臭氧伤害,或叶脉间黄化(万寿菊和矮牵牛),或出现白色斑点(圆叶牵牛),且随臭氧浓度升高其黄化程度加剧,白色斑点亦扩张形成白色斑块,最终叶片从症状形成的地方开始干枯。2)臭氧暴露加剧了供试植物叶片膜脂过氧化程度,但对可溶性蛋白含量没有显著影响,说明植物生长后期臭氧暴露并没有造成蛋白质退化进而引起植物抗臭氧胁迫能力的下降。3)臭氧暴露后万寿菊叶片茉莉酸含量降低,矮牵牛叶片水杨酸含量显著升高,而圆叶牵牛既有水杨酸含量的升高又有茉莉酸含量的降低,说明不同植物对臭氧伤害的激素响应是不一致的,茉莉酸保护能力减弱引起了臭氧对万寿菊叶片伤害,水杨酸过度累积造成了矮牵牛叶片的臭氧直接伤害,而圆叶牵牛的臭氧伤害则是2种原因都可能存在。因此,在大气臭氧浓度尚不能有效控制的情况下,明确不同植物臭氧伤害形成的激素响应,以采取针对性保护措施维持其最大生态效益。  相似文献   
57.
Howard Davis 《Disasters》2017,41(1):55-76
Local authorities in the United Kingdom are required to ‘lead’ multi‐agency humanitarian responses to major disasters. Concerns mounted in the late twentieth century that responses to people bereaved in the immediate aftermath of such events at best failed to meet their needs and at worst compounded their distress. Subsequent reviews and reforms reframed some victim needs as ‘rights’ and established legal, administrative, and practice frameworks to improve matters. Local authority ‘crisis support’, provided in partnership with other actors, lies at the heart of the UK's contemporary emergency response to the bereaved. Drawing on primary research on the development and the deployment of crisis support in a local authority, and while acknowledging both incident‐ and context‐related difficulties, this paper considers the significance of challenges with their origins in organisational factors. Recent developments within and between responders may exacerbate them. This paper argues, therefore, that further research into such developments is necessary.  相似文献   
58.
A number of studies have examined emotional and belief responses following a disaster, yet there has been limited comparative analysis of responses to disasters in different places. This paper reviews the results of 366 questionnaires that evaluated key emotional and belief concepts in Haiti after the earthquake on 12 January 2010 (n=212) and in Indonesia after the earthquake in Yogyakarta on 27 May 2006 (n=154). The results indicate significant differences between the responses in the two settings, particularly in relation to feelings of impunity, self‐blame for the disaster, regret about pre‐earthquake behaviour, and a sense of justice in the world. Furthermore, the impacts of age, education, and gender on responses also were different in the two case study sites. Overall, the results suggest that understanding the cultural, religious, and social contexts of different disaster locales is important in comprehending the emotions and beliefs that manifest themselves in the wake of a major disaster.  相似文献   
59.
近断层地震动运动特征对长周期结构地震响应的影响分析   总被引:3,自引:0,他引:3  
选择台湾集集近断层地震动记录作为地震动输入,系统考察了近断层地震动破裂方向性、上盘效应、脉冲效应等运动特征对双线性单自由度体系、长周期隔震建筑和斜拉桥结构地震响应的影响。计算结果表明,脉冲型地震动对结构的效应随双线性单自由度体系的初始自振周期增大而变大,在长周期段结构的脉冲效应最显著;地震动破裂方向性和上盘效应对单自由度体系位移需求的影响与体系周期有关。对于隔震建筑和大跨度斜拉桥等长周期结构,近断层地震动破裂方向性对结构的效应较显著;上盘效应对长周期结构的影响明显;地震动的速度脉冲运动特征总的来说放大了结构响应。  相似文献   
60.
To establish allowable daily intakes for humans from animal bioassay experiments, benchmark doses corresponding to low levels of risk have been proposed to replace the no-observed-adverse-effect level for non-cancer endpoints. When the experimental outcomes are quantal, each animal can be classified with or without the disease. The proportion of affected animals is observed as a function of dose and calculation of the benchmark dose is relatively simple. For quantitative responses, on the other hand, one method is to convert the continuous data to quantal data and proceed with benchmark dose estimation. Another method which has found more popularity (Crump, Risk Anal 15:79–89; 1995) is to fit an appropriate dose–response model to the continuous data, and directly estimate the risk and benchmark doses. The normal distribution has often been used in the past as a dose–response model. However, for non-symmetric data, the normal distribution can lead to erroneous results. Here, we propose the use of the class of beta-normal distribution and demonstrate its application in risk assessment for quantitative responses. The most important feature of this class of distributions is its generality, encompassing a wide range of distributional shapes including the normal distribution as a special case. The properties of the model are briefly discussed and risk estimates are derived based on the asymptotic properties of the maximum likelihood estimates. An example is used for illustration.
Mehdi RazzaghiEmail:
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