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541.
542.
Louise Osborne Kate D. L. Umbers Patricia R. Y. Backwell J. Scott Keogh 《Die Naturwissenschaften》2012,99(10):869-872
The ability to distinguish between familiar and unfamiliar conspecifics is important for many animals, especially territorial species since it allows them to avoid unnecessary interactions with individuals that pose little threat. There are very few studies, however, that identify the proximate cues that facilitate such recognition in visual systems. Here, we show that in tawny dragons (Ctenophorus decresii), males can recognize familiar and unfamiliar conspecific males based on morphological features alone, without the aid of chemical or behavioural cues. We further show that it is the colour pattern of the throat patches (gular) that facilitates this recognition. 相似文献
543.
Acartia tonsa Dana is a dominant copepod in coastal waters and is therefore an important link in the food web between microplankton and
higher trophic levels. RNA:DNA ratios have been used to describe growth and nutritional condition of field-collected copepods
and to show strong correlation between RNA:DNA ratios and group egg production (EP). A method was developed using a sensitive,
nucleic acid-specific fluorescent dye, and automated microplate fluorometer to measure DNA, RNA, and the RNA:DNA ratio of
individual A. tonsa. DNA, RNA, and RNA:DNA ratios and EP were all significantly higher in copepods fed Thalassiosira sp. compared to starved copepods. There was a general trend toward an increase in RNA:DNA ratios with increase in EP, but
due to the high degree of variation in both RNA:DNA ratios and EP among individual copepods there was no significant correlation
between RNA:DNA ratios and EP. Significant differences in RNA:DNA ratios between fed (7.2) and starved (3.3) copepods were
found after 2 days. This assay may be applied to other species of copepods sampled in the field to provide an index of the
health of planktonic food webs. 相似文献
544.
545.
Yacov Y Haimes W Scott Nainis Seymour Goldstone 《Journal of Environmental Economics and Management》1977,4(3):219-238
The objective of the study was to investigate and develop new alternative approaches to effectively meeting the federal SOx and particulate ambient air quality standards at cost savings. Since air pollution control costs would very likely be passed along to the consumer, it is in the best interests of the consumer and industry to find the least-cost alternative policies. Cost-sharing possesses advantages not shared by other control schemes, such as emissions taxes, auctioning of “pollution certificates,” or other methods. The results of this paper indicate that the cost-sharing approach is useful for particulates control in order to minimize the burden of plants already performing substantial control who may require significant added capital investment beyond their initial amount. For SOξ emissions control the cost-sharing analysis calculations show significant savings in nearly all situations, whether or not stack gas treatment methods were assumed available. Furthermore, the cost-sharing approach may allow further savings when the particular cost requirements of an individual firm differ substantially from the average engineering cost estimates. A cost-sharing option should thus be included in implementation plans as an option to be used by industries at their own initiative. The spatial characteristics of emissions resulting from a particular application of the cost-sharing approach are considered. A spatial airshed emissions allocation model is discussed as a useful method of evaluating cost sharing. 相似文献
546.
547.
L. Scott Mills‡ Stephen G. Hayes Calib Baldwin Michael J. Wisdom John Citta‡ David J. Mattson Kerry Murphy 《Conservation biology》1996,10(3):863-873
Population viability analysis programs are being used increasingly in research and management applications, but there has not been a systematic study of the congruence of different program predictions based on a single data set. We performed such an analysis using four population viability analysis computer programs: GAPPS, INMAT, RAMAS/AGE, and VORTEX. The standardized demographic rates used in all programs were generalized from hypothetical increasing and decreasing grizzly bear ( Ursus arctos horribilis ) populations. Idiosyncracies of input format for each program led to minor differences in intrinsic growth rates that translated into striking differences in estimates of extinction rates and expected population size. In contrast, the addition of demographic stochasticity, environmental stochasticity, and inbreeding costs caused only a small divergence in viability predictions. But, the addition of density dependence caused large deviations between the programs despite our best attempts to use the same density-dependent functions. Population viability programs differ in how density dependence is incorporated, and the necessary functions are difficult to parameterize accurately. Thus, we recommend that unless data clearly suggest a particular density-dependent model, predictions based on population viability analysis should include at least one scenario without density dependence. Further, we describe output metrics that may differ between programs; development of future software could benefit from standardized input and output formats across different programs. 相似文献
548.
Petroleum resources are declining on the continental shelf and will, eventually, result in the loss of ~?30,000 jobs in related industries. Retired oil and gas platforms could be redeployed to culture fish and employ citizens in coastal areas. The Energy Policy Act 2005 Section 388 of Public Law [PL] 109-58 30 CFR 285.1000 Subpart J encourages the use of the retired structures for alternate uses. At present, there are no fishermen currently taking advantage of this legislation. We suggest amending existing laws to improve the likelihood that retired platforms are used to culture fish and invertebrates. In the future, the abandoned oil and gas infrastructure could also be used to recover stranded petroleum and reserves located in deeper horizons. 相似文献
549.
Jeff L. Gentry Alexandra Salter‐Blanc Keith Sheets Bhawana Sharma Laura Tochko Scott Martin 《补救:环境净化治理成本、技术与工艺杂志》2020,30(2):5-14
A novel, multilayered shoreline cap was designed and installed to mitigate the release of petroleum light nonaqueous phase liquid (LNAPL) and dissolved‐phase groundwater constituents to the Willamette River in Portland, OR. Releases of LNAPL related to upland impacts caused occasional sheens on a portion of the river within the Portland Harbor Superfund Site. The frequency and volume of sheens decreased following the installation of an upland sheet pile barrier wall, but occasional sheens related to LNAPL impacts stranded downgradient of the wall continued–prompting the design of a shoreline remedy. Because the site is located within the Portland Harbor Superfund Site, the cap was designed to mitigate sheen and to meet the objectives specified in the Portland Harbor Record of Decision including limiting the discharge of certain dissolved‐phase constituents of interest. The cap design was the first instance of combining an oleophilic bio‐barrier to mitigate sheen and an activated carbon layer to capture dissolved‐phase constituents. No sheens have been visually observed since cap installation. 相似文献
550.
Linda Godfrey Dianne Scott Mark Difford Cristina Trois 《Waste management (New York, N.Y.)》2012,32(11):2154-2162
An empirical study was undertaken with 31 organisations submitting data to the South African Waste Information System (SAWIS) in order to explore the relationship between data and resultant waste knowledge generated through a process of learning. The results show that of the three constructs of knowledge (experience, data/information, and theory), experience has the greatest influence on building waste knowledge, nearly twice that of data/information and three times that of theory. Together the three constructs account for 54.1% of the variance in knowledge. Respondents from municipalities and private waste organisations reflect two distinct sub-groups in the data set. While the theoretical model remains the same for the two sub-groups, the way in which knowledge is constructed, and the variance in knowledge explained by the model, differs for the two. A mixed methods research design, combining quantitative statistical analysis and rich qualitative data, contributes to a comprehensive interpretation of the role of waste data in building knowledge in South Africa. While waste data has a minor influence on building knowledge, respondents acknowledge that waste data does have a positive impact on the way their organisations manage waste. However, it is not the data, but rather the resultant waste knowledge and raised level of awareness that causes the operational response. Experience is obtained predominantly through learning from others. Respondents in municipalities, emphasised learning from consultants, landfill site contractors, and colleagues in city-twinning programmes, while respondents in private waste companies, emphasised learning from experienced, senior colleagues. 相似文献