全文获取类型
收费全文 | 2787篇 |
免费 | 77篇 |
国内免费 | 24篇 |
专业分类
安全科学 | 126篇 |
废物处理 | 110篇 |
环保管理 | 814篇 |
综合类 | 308篇 |
基础理论 | 670篇 |
环境理论 | 1篇 |
污染及防治 | 584篇 |
评价与监测 | 158篇 |
社会与环境 | 82篇 |
灾害及防治 | 35篇 |
出版年
2023年 | 14篇 |
2022年 | 22篇 |
2021年 | 30篇 |
2020年 | 20篇 |
2019年 | 33篇 |
2018年 | 51篇 |
2017年 | 48篇 |
2016年 | 63篇 |
2015年 | 59篇 |
2014年 | 59篇 |
2013年 | 295篇 |
2012年 | 111篇 |
2011年 | 138篇 |
2010年 | 113篇 |
2009年 | 124篇 |
2008年 | 157篇 |
2007年 | 150篇 |
2006年 | 129篇 |
2005年 | 97篇 |
2004年 | 79篇 |
2003年 | 99篇 |
2002年 | 87篇 |
2001年 | 58篇 |
2000年 | 46篇 |
1999年 | 25篇 |
1998年 | 43篇 |
1997年 | 28篇 |
1996年 | 38篇 |
1995年 | 47篇 |
1994年 | 31篇 |
1993年 | 45篇 |
1992年 | 40篇 |
1991年 | 16篇 |
1990年 | 23篇 |
1989年 | 19篇 |
1988年 | 25篇 |
1987年 | 16篇 |
1986年 | 19篇 |
1985年 | 28篇 |
1984年 | 25篇 |
1983年 | 24篇 |
1982年 | 34篇 |
1981年 | 34篇 |
1980年 | 32篇 |
1979年 | 21篇 |
1978年 | 23篇 |
1977年 | 12篇 |
1976年 | 8篇 |
1974年 | 8篇 |
1972年 | 10篇 |
排序方式: 共有2888条查询结果,搜索用时 10 毫秒
1.
Dr. J. F. Bruch P. Metezeau N. Garcia-Fonknechten Y. Richard V. Tricottet B.-L. Hsi A. Kitzis C. Julien E. Papiernik 《黑龙江环境通报》1991,11(10):787-798
Three monoclonal antibodies (MAbs) against trophoblast (GB17, GB21, and GB25) and flow cytometry were used to sort trophoblast-like cells (TLCs) from peripheral blood of pregnant women. Sorted TLCs were processed for electron microscopy and fetal DNA amplification of the Y-specific sequences from mothers carrying male fetuses. At the ultra-structural level, most of the nucleated cells had the morphology of leucocytes, suggesting maternal contaminants, and we did not find the characteristic features of the free inter-villous trophoblast cells. Nevertheless, polymerase chain reaction (PCR) analysis showed an amplification of Y-specific sequences in two out of three samples of sorted TLCs. These results suggest that besides the maternal leucocytes, sufficient trophoblast nucleated fetal cells can be obtained using cell enrichment by sorting. This sensitive method holds promise for non-invasive prenatal diagnosis of fetal sex and if sufficient Y(positive) nuclei are found, for the diagnosis of selected numerical chromosome abnormalities. 相似文献
2.
Critical loads offer a unique way of evaluating impacts of acid deposition by quantifying environmental sensitivity. The critical loads of acidity for UK peat soils have been based upon an arbitrary reduction in pH of 0.2 units. This chemical shift needs to be better related to adverse effects on sensitive biological receptors. It is known that effective precipitation pH equates closely to soil solution pH, and the latter is directly linkable to biotic effects of pH change. On continuation of a long-term experiment assessing impacts of simulated acid rain on peat microcosms in a realistic outdoor environment, Calluna vulgaris continued to flourish at acid deposition loads well above the existing critical load. Calluna plants were harvested and analysed, and acid deposition treatments to the microcosms continued to allow natural vegetation to regenerate. A diverse mixture of moorland plants and bryophytes established at acidity treatments well above the existing critical load, and only a very high acid load resulted in no natural regeneration. A critical effective rain pH value of 3.6 is suggested as a basis for setting critical loads. At this pH, Calluna grows well, and a healthy diverse vegetation community re-establishes when harvested. It is suggested that the peat critical load should be set at the acid load that, at any specific site, would result in a mean effective precipitation pH of 3.6. 相似文献
3.
4.
5.
Clark Burton N Adhikari A Grinshpun SA Hornung R Reponen T 《Journal of environmental monitoring : JEM》2005,7(5):475-480
The objective of this study was to determine filter materials and extraction methods that are appropriate to use for environmental sampling of B. anthracis. Four types of filters were tested: mixed cellulose ester (MCE) with a pore size of 3 microm, polytetrafluoroethylene (PTFE) with pore sizes of 1 and 3 microm, and gelatin with a pore size of 3 microm. Bacillus subtilis var. niger endospores (also known as Bacillus globigii[BG]) were used as a surrogate for B. anthracis. Endospores were collected into Button Inhalable Aerosol Samplers with sampling times of 15 minutes, 1 hour, and 4 hours. Physical collection efficiency was determined by measuring upstream and downstream B. subtilis concentrations with an optical particle counter. Vortexing with ultrasonic agitation and vortexing with shaker agitation extraction methods were evaluated. The MCE, 1 microm PTFE, and gelatin filters provided physical collection efficiencies of 94% or greater. The 3 microm PTFE filter showed inconsistent physical efficiency characteristics between filters. Epifluorescence microscopic analysis of the gelatin filter extraction fluid revealed the presence of contamination by non-culturable bacteria. Mean differences for microbial culturability were not statistically significant for filter materials and extraction methods. However, the vortexing with shaker agitation extraction method resulted in higher total microbial counts in the extraction fluids for MCE and 1 microm PTFE filters when compared to vortexing with ultrasonic agitation. In summary, the MCE and 1 microm PTFE filters in combination with vortexing and shaker extraction demonstrated the best performance for the filter collection and extraction of BG spores. 相似文献
6.
Richard A. Sims Kenneth A. Baldwin H. Maureen Kershaw Yonghe Wang 《Environmental monitoring and assessment》1996,39(1-3):471-484
Selected data on site, vegetation cover, and soil, including soil moisture regime (SMR), were collected from 2 167 field plots in northwestern Ontario, Canada. SMR provides an estimate of an averaged, annualized soil moisture supply throughout a complete vegetation cycle. SMR is based upon a relative scale that subjectively ranks sites from , 0, and 1 through 9 along a soil moisture continuum which relates to a dry to wet gradient. SMR may be generally correlated to tree growth, stand composition, degree of competition, nutrient availability and overall site quality.This paper reports on relationships between SMR and major tree species. Results highlight relationships between SMR class and the broad ecological ranges of several tree species. In northwestern Ontario, the determination of SMR can help resource managers to better understand the ecology of boreal sites. 相似文献
7.
Meklin T Haugland RA Reponen T Varma M Lummus Z Bernstein D Wymer LJ Vesper SJ 《Journal of environmental monitoring : JEM》2004,6(7):615-620
Indoor mold concentrations were measured in the dust of moldy homes (MH) and reference homes (RH) by quantitative PCR (QPCR) assays for 82 species or related groups of species (assay groups). About 70% of the species and groups were never or only rarely detected. The ratios (MH geometric mean : RH geometric mean) for 6 commonly detected species (Aspergillus ochraceus, A. penicillioides, A. unguis, A. versicolor, Eurotium group, and Cladosporium sphaerospermum) were >1 (Group I). Logistic regression analysis of the sum of the logs of the concentrations of Group I species resulted in a 95% probability for separating MH from RH. These results suggest that it may be possible to evaluate whether a home has an abnormal mold condition by quantifying a limited number of mold species in a dust sample. Also, four common species of Aspergillus were quantified by standard culturing procedures and their concentrations compared to QPCR results. Culturing underestimated the concentrations of these four species by 2 to 3 orders of magnitude compared to QPCR. 相似文献
8.
9.
Richard J. Stock M.D. 《黑龙江环境通报》1982,2(2):133-137
A case of fetal death secondary to a needle laceration during a second trimester amniocentesis is presented. The need for careful pathologic evaluation of fetuses lost subsequent to these procedures is stressed. 相似文献
10.