全文获取类型
收费全文 | 825篇 |
免费 | 222篇 |
国内免费 | 165篇 |
专业分类
安全科学 | 48篇 |
废物处理 | 7篇 |
环保管理 | 45篇 |
综合类 | 332篇 |
基础理论 | 640篇 |
污染及防治 | 62篇 |
评价与监测 | 40篇 |
社会与环境 | 23篇 |
灾害及防治 | 15篇 |
出版年
2024年 | 1篇 |
2023年 | 44篇 |
2022年 | 40篇 |
2021年 | 50篇 |
2020年 | 49篇 |
2019年 | 37篇 |
2018年 | 89篇 |
2017年 | 57篇 |
2016年 | 47篇 |
2015年 | 68篇 |
2014年 | 63篇 |
2013年 | 101篇 |
2012年 | 62篇 |
2011年 | 73篇 |
2010年 | 57篇 |
2009年 | 48篇 |
2008年 | 47篇 |
2007年 | 38篇 |
2006年 | 40篇 |
2005年 | 26篇 |
2004年 | 19篇 |
2003年 | 23篇 |
2002年 | 18篇 |
2001年 | 11篇 |
2000年 | 13篇 |
1999年 | 18篇 |
1998年 | 13篇 |
1997年 | 9篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1977年 | 2篇 |
排序方式: 共有1212条查询结果,搜索用时 171 毫秒
401.
Catalina Munteanu Cornelius Senf Mihai D. Nita Francesco Maria Sabatini Julian Oeser Rupert Seidl Tobias Kuemmerle 《Conservation biology》2022,36(2):e13820
High-conservation-value forests (HCVFs) are critically important for biodiversity and ecosystem service provisioning, but they face many threats. Where systematic HCVF inventories are missing, such as in parts of Eastern Europe, these forests remain largely unacknowledged and therefore often unprotected. We devised a novel, transferable approach for detecting HCVFs based on integrating historical spy satellite images, contemporary remote sensing data (Landsat), and information on current potential anthropogenic pressures (e.g., road infrastructure, population density, demand for fire wood, terrain). We applied the method to the Romanian Carpathians, for which we mapped forest continuity (1955–2019), canopy structural complexity, and anthropogenic pressures. We identified 738,000 ha of HCVF. More than half of this area was identified as susceptible to current anthropogenic pressures and lacked formal protection. By providing a framework for broad-scale HCVF monitoring, our approach facilitates integration of HCVF into forest conservation and management. This is urgently needed to achieve the goals of the European Union's Biodiversity Strategy to maintain valuable forest ecosystems. 相似文献
402.
本文优化了加速溶剂萃取-超高效液相色谱测定土壤中苯并(a)芘的方法。样品经加速溶剂提取,逐级减压浓缩,0.25um滤膜过滤净化,超高效液相色谱(UPLC)测定。结果表明,标准溶液苯并(a)芘含量在3.125~lOOug/L范围内,苯并(a)芘的线性呈良好的线性关系,相关系数为0.9999,该方法的检出限和测定下限分别为0.015μg/kg和0.060μg/kg。将该方法用于4个地区土壤样品的测定,苯并(a)芘含量在0.04~6.26ug/kg之间,空白加标回收率为75.2%~96.4%之间,各项指控指标符合检测要求。 相似文献
403.
以泥鳅的胚胎及仔鱼为试验材料,选择胚胎发育的4个不同时期(囊胚期、原肠胚中期、神经胚期、尾芽期)及仔鱼期为处理开始的时间点,探讨了离子液体[C8mim]Cl的毒性作用。结果表明,随着[C8mim]Cl浓度增加,泥鳅胚胎的孵化率下降,畸形率上升,具有明显的剂量-效应关系,67~150 mg·L-1的[C8mim]Cl对泥鳅胚胎均表现出明显的致畸毒性效应;随着[C8mim]Cl浓度增加,泥鳅仔鱼死亡率上升,而100~225 mg·L-1的[C8mim]Cl对泥鳅仔鱼具有明显的致畸、致死作用。其中,[C8mim]Cl对孵出期泥鳅仔鱼的24 h、48 h的半致死浓度分别为97.95和86.77 mg·L-1;而[C8mim]Cl对孵出后3 d泥鳅仔鱼的24 h、48 h的半致死浓度分别为73.77和40.98 mg·L-1。由上可知,在一定的剂量内,[C8mim]Cl对泥鳅胚胎及仔鱼的发育有明显的致畸、致死作用,这为离子液体[C8mim]Cl的合理使用提供了理论依据。 相似文献
404.
Tianxiang Xia Lin Jiang Xiaoyang Jia Maosheng Zhong Jing Liang 《Frontiers of Environmental Science & Engineering》2014,8(3):441-450
Application of Probabilistic Risk Assessment (PRA) and Deterministic Risk Assessment (DRA) at a coking plant site was compared. By DRA, Hazard Quotient (HQ) following exposure to Naphthalene (Nap) and Incremental Life Cancer Risk (ILCR) following exposure to Benzo(a)pyrene (Bap) were 1.87 and 2.12 × 104. PRA revealed valuable information regarding the possible distribution of risk, and risk estimates of DRA located at the 99.59th and 99.76th percentiles in the risk outputs of PRA, which indicated that DRA overestimated the risk. Cleanup levels corresponding acceptable HQ level of 1 and ILCR level of 104 were also calculated for both DRA and PRA. Nap and Bap cleanup levels were 192.85 and 0.14mg.kg-1 by DRA, which would result in only 0.25% and 0.06% of the exposed population to have a risk higher than the acceptable risk, according to the outputs of PRA. The application of PRA on cleanup levels derivation would lift the cleanup levels 1.9 times for Nap and 2.4 times for Bap than which derived by DRA. For this coking plant site, the remediation scale and cost will be reduced in a large portion once the method of PRA is used. Sensitivity analysis was done by calculating the contribution to variance for each exposure parameter and it was found that contaminant concentration in the soil (Cs), exposure duration (ED), total hours spent outdoor per day (ETout), soil ingestion rate (IRs), the air breathing rate (IRa) and bodyweight (BW) were the most important parameters for risk and cleanup levels calculations. 相似文献
405.
The distribution and transportation of Dissolved and Dispersed Petroleum Hydrocarbon (DDPH) were investigated in the Aegean Sea with the hydrodynamics of the water masses of the region. It is clear that distribution of this pollutant is strongly affected by physical dynamics of environment. The data were collected during cruises in November 1994, in the framework of National Marine Measurement and Monitoring Programme in the Aegean Sea. In the present study additionally the Chlorophyll‐a was measured fluorometrically and there is good correlation between petroleum hydrocarbon and chlorophyll‐a in the Aegean Sea. DDPH data was used to search origin of hydrocarbons: biogenic or non biogenic. 相似文献
406.
Land and resource managers often use detection–nondetection surveys to monitor the populations of species that may be affected by factors such as habitat alteration, climate change, and biological invasions. Relative to mark‐recapture studies, using detection–nondetection surveys is more cost‐effective, and recent advances in statistical analyses allow the incorporation of detection probability, covariates, and multiple seasons. We examined the efficacy of using detection–nondetection data (relative to mark‐recapture data) for monitoring population trends of a territorial species, the California Spotted Owl (Strix occidentalis occidentalis). We estimated and compared the finite annual rates of population change (λt) and the resulting realized population change (Δt) from both occupancy and mark‐recapture data collected over 18 years (1993–2010). We used multiseason, robust‐design occupancy models to estimate that territory occupancy declined during our study (Δt = 0.702, 95% CI 0.552–0.852) due to increasing territory extinction rates ( = 0.019 [SE 0.012]; = 0.134 [SE 0.043]) and decreasing colonization rates ( = 0.323 [SE 0.124]; = 0.242 [SE 0.058]). We used Pradel's temporal‐symmetry model for mark‐recapture data to estimate that the population trajectory closely matched the trends in territory occupancy (Δt = 0.725, 95% CI 0.445–1.004). Individual survival was constant during our study ( = 0.816 [SE 0.020]; = 0.815 [SE 0.019]), whereas recruitment declined slightly ( = 0.195 [SE 0.032]; = 0.160 [SE 0.023]). Thus, we concluded that detection–nondetection data can provide reliable inferences on population trends, especially when funds preclude more intensive mark‐recapture studies. Relación entre Ocupación y Abundancia en una Especie Territorial, el Búho Moteado de California 相似文献
407.
土壤B[a]P叠加污染对蚯蚓体腔细胞SOD、POD和MDA的毒性效应 总被引:1,自引:0,他引:1
采用累积试验方法,研究土壤苯并[a]芘(B[a]P)多次叠加污染对赤子爱胜蚓(Eisenia foetida)体腔细胞超氧化物歧化酶(SOD)、过氧化物酶(POD)和丙二醛(MDA)的毒性效应.结果表明,随着土壤中B[a]P暴露时间的延长,蚯蚓体腔细胞的SOD、POD活力和MDA含量呈初期(1~14 d)下降速率较快,尔后(14~56 d)下降速率减小的变化趋势.在叠加污染条件下,0~ 20 cm深度土壤中蚯蚓体腔细胞SOD活力和MDA含量在14d时分别比一次污染低20.97%和15.96%,POD活力比一次污染高20.44%;而在>20~40 cm深度土壤中蚯蚓体腔细胞SOD、POD活力和MDA含量在14d时分别比一次污染低52.89%、18.00%和70.60%.表明B[a]P叠加污染土壤中蚯蚓体腔细胞的毒性效应低于一次污染. 相似文献
408.
地质灾害危险性评估分级因素的探讨 总被引:1,自引:0,他引:1
地质灾害危险性评估工作级别由建设项目重要性和评估区地质环境条件复杂程度这两个因素决定.在分析现行相关标准和研究成果的基础上,指出建设项目重要性可依次由省部级相关技术标准、项目行政审批权限级别、预估灾后损失程度顺序确定,以先符合者为准;指出评估区地质环境条件复杂程度可由地质灾害发育程度、地形与地貌复杂程度、地质构造复杂程度、岩土体工程地质性质、水文地质条件、破坏地质环境的人类工程活动程度等6项判定因素确定,并初步确定了地质灾害发育程度、地形与地貌复杂程度、地质构造复杂程度、岩土体工程地质性质、水文地质条件和破坏地质环境的人类工程活动程度等分级评价标准. 相似文献
409.
410.
Adeline Tarantini Marie-Blanche Personnaz Jean-Luc Besombes Jean-Luc Jafrezzo 《毒物与环境化学》2013,95(5):941-954
Particulate organic matter (PM) present in the atmosphere is a complex mixture of chemicals like polycyclic aromatic hydrocarbons (PAH) that may exert adverse health effects including respiratory and cardiovascular disturbances and cancer. In this study, airborne samples from environmental or industrial areas exhibiting different physicochemical composition were compared for their capacities to induce DNA damage in human hepatocytes HepG2. DNA strand breaks and DNA adducts formed by benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE), the most reactive metabolite of the carcinogenic benzo[a]pyrene (B[a]P), were measured with the comet assay and by high-performance liquid chromatography (HPLC)/mass spectrometry, respectively. Cells were exposed to organic matter extracted from PM. Experiments were performed either at a constant concentration of B[a]P or at concentrations corresponding to fixed air volumes. Results show that industrial extracts tend to produce more benzo[a]pyrene diol epoxide-N 2-2′-deoxyguanosine (BPDE-N 2-dGuo) DNA adducts than strand breaks, whereas the opposite was observed with environmental extracts. The chemical composition of the extracts significantly impacts the nature and levels of DNA damage. The amount of B[a]P and interaction with other contaminants in the extracts need to be considered to explain the formation of DNA damage. These results emphasize the use of in vitro tests as promising and complementary tools to widely used toxic equivalent factor (TEF) approach in order to assess health hazards related to chemical exposure of the general population. 相似文献