全文获取类型
收费全文 | 8082篇 |
免费 | 90篇 |
国内免费 | 244篇 |
专业分类
安全科学 | 159篇 |
废物处理 | 396篇 |
环保管理 | 921篇 |
综合类 | 1358篇 |
基础理论 | 1977篇 |
污染及防治 | 1998篇 |
评价与监测 | 608篇 |
社会与环境 | 950篇 |
灾害及防治 | 49篇 |
出版年
2023年 | 58篇 |
2022年 | 131篇 |
2021年 | 105篇 |
2020年 | 68篇 |
2019年 | 99篇 |
2018年 | 145篇 |
2017年 | 155篇 |
2016年 | 213篇 |
2015年 | 159篇 |
2014年 | 259篇 |
2013年 | 699篇 |
2012年 | 280篇 |
2011年 | 375篇 |
2010年 | 310篇 |
2009年 | 342篇 |
2008年 | 395篇 |
2007年 | 401篇 |
2006年 | 308篇 |
2005年 | 293篇 |
2004年 | 288篇 |
2003年 | 280篇 |
2002年 | 267篇 |
2001年 | 341篇 |
2000年 | 216篇 |
1999年 | 115篇 |
1998年 | 86篇 |
1997年 | 84篇 |
1996年 | 107篇 |
1995年 | 126篇 |
1994年 | 96篇 |
1993年 | 85篇 |
1992年 | 90篇 |
1991年 | 92篇 |
1990年 | 79篇 |
1989年 | 71篇 |
1988年 | 69篇 |
1987年 | 75篇 |
1986年 | 52篇 |
1985年 | 63篇 |
1984年 | 63篇 |
1983年 | 59篇 |
1982年 | 58篇 |
1981年 | 64篇 |
1980年 | 47篇 |
1979年 | 46篇 |
1977年 | 38篇 |
1976年 | 36篇 |
1974年 | 34篇 |
1973年 | 43篇 |
1972年 | 51篇 |
排序方式: 共有8416条查询结果,搜索用时 234 毫秒
731.
The effects of varying the concentration of phosphorus and potassium independently in the growing medium of pot-grown tomato plants on their subsequent susceptibility in normal medium to vascular wilt caused by Verticillium dahliae Kleb. were studied. The degree of host invasion was measured by estimating the chitin component of diseased tissue. Different levels of potassium had little effect on the degree of invasion of inoculated stems, but this was considerably enhanced in plants raised in the absence of phosphorus. Root inoculated plants were particularly resistant when raised in nutrients totally lacking in potassium, and very susceptible when raised in the absence of phosphorus. 相似文献
732.
Behavior of dialifor, dimethoate, and methidathion in artificially fortified grape juice processed into wine. 总被引:1,自引:0,他引:1
N S Kawar Y Iwata M E Düsch F A Gunther 《Journal of environmental science and health. Part. B》1979,14(5):505-513
Dialifor and methidathion were added to diluted "Zinfandel" grape concentrate at 25 ppm and dimethoate at 1.0 and 25 ppm prior to fermentation with Saccharomyces cerevisiae. The finished wine 56 days later contained 10% (2.5 ppm) of the dialifor, 46% (12 ppm) of the methidathion and 85% (21 and 0.98 ppm) of the dimethoate added to the grape must. Residues in wine stored at 24 degrees C dissipated by hydrolysis; half-lives in wine were 7 days for dialifor and methidathion and 30 days for dimethoate. Residues were unchanged in wine in frozen storage for one year. Analysis of seven commercial wines for dimethoate indicated less than 0.03 ppm dimethoate was present; identity could not be confirmed by thin-layer chromatography at this level. 相似文献
733.
734.
The southern pine beetle, Dendroctonus frontalis Zimmermann, is a major insect pest of pines in the southern U.S.A. A population dynamic model of D. frontalis within an infestation was developed. The model is based on the integration of several component submodels that describe individual life stage processes of the beetle. The inclusion of variable forest stand density and microclimate conditions results in a model response which closely follows actual field responses. A sensitivity analysis was performed to investigate effects of weather conditions and the importance of the spatial patterns within the forest. 相似文献
735.
The internodal area of growing cord grass (Spartina alterniflora Loisel) is a microcosm colonized by the mycelium and heretofore unreported hyphopodial appendages of the fungus Sphaerulina pedicellata. As the plant matures and this area senesces during the late summer and fall, sexual stages of this and other fungi develop. Scanning electron micrographs revealed that this biomass supports bacterial growth and is grazed by nematodes and mites. 相似文献
736.
This study aimed to identify distribution of metals and the influential factors on metal concentrations in incineration residues. Bottom ash and fly ash were sampled from 19 stoker and seven fluidized bed incinerators, which were selected to have a variety of furnace capacity, furnace temperature, and input waste. In the results, shredded bulky waste in input waste increased the concentration of some metals, such as Cd and Pb, and the effect was confirmed by analysis of shredded bulky waste. During MSW incineration, lithophilic metals such as Fe, Cu, Cr, and Al remained mainly in the bottom ash while Cd volatilized from the furnace and condensed to the fly ash. About two thirds of Pb and Zn was found in the bottom ash despite their high volatility. Finally, based on the results obtained in this study, the amount of metal in incineration residues of MSW was calculated and the loss of metal was estimated in terms of mass and money. A considerable amount of metal was found to be lost as waste material by landfilling of incineration residues. 相似文献
737.
Osuna MB van Hullebusch ED Zandvoort MH Iza J Lens PN 《Journal of environmental quality》2004,33(4):1256-1270
A sequential extraction procedure was applied to two anaerobic methanogenic sludges (Eerbeek and Nedalco) to examine the speciation of micro- and macronutrients in the sludges after cobalt sorption by exposing the sludge to a 1 mM Co solution for 4 d at pH 7 and 30 degrees C. The effect of different physicochemical conditions on cobalt sorption was studied as well: effect of pH (6-8), effect of competition by a second trace element (Ni or Fe), modification of the granular matrix by glutaraldehyde or heat treatment, and EDTA (ethylenediaminetetraacetic acid) addition. Sorbed Co was found to distribute between the carbonates, organic matter + sulfides, and residual fractions. Cobalt adsorption resulted in an antagonistic interaction with other metals present in the granular matrix, evidenced by the solubilization of other trace elements (e.g., Ni, Cu, and Zn) as well as macronutrients (especially Ca and Fe). Modification of the sludge matrix by glutaraldehyde or heat treatment, or exposure to EDTA, led to serious modifications of the Co sorption capacity and strong interactions with multivalent cations (i.e., Ca(2+) and Fe(2+)). 相似文献
738.
A 105-d field experiment was conducted to determine the potential of the slow-release fertilizer, Osmocote (Scotts, Marysville, OH), to stimulate the indigenous microbial biodegradation of petroleum hydrocarbons in an oil-spiked beach sediment on an intertidal foreshore in Singapore. Triplicate microcosms containing 80 kg of weathered sediment, spiked with 5% (w/w) Arabian light crude oil and 1.2% (w/w) Osmocote pellets, were established, together with control microcosms minus Osmocote. Relative to the control, the presence of the Osmocote sustained a significantly higher level of nutrients (NH(4)(+)-N, NO(3)(-)-N, and PO(4)(3-)-P) in the sediment pore water over the duration of the experiment. The metabolic activity of the indigenous microbial biomass, as measured using an intracellular dehydrogenase enzyme assay, was also significantly enhanced over the duration of the experiment in amended sediments. The loss of total recoverable petroleum hydrocarbons (TRPH) and biodegradation of total n-alkanes (C(10)-C(33)), branched alkanes (pristane and phytane), as well as total target polycyclic aromatic hydrocarbons (PAHs) (two- to six-ring), in both the control and Osmocote-amended sediments, followed a first-order biodegradation model. The first-order loss rate of total recoverable petroleum hydrocarbons was 2.57 times greater than that of the control. The hopane-normalized rate constants for total n-alkane, branched alkane, and total target PAH biodegradation in the Osmocote-treated sediments were 3.95-, 5.50-, and 2.45-fold higher than the control, respectively. Overall, the presence of Osmocote was able to significantly enhance and accelerate the biodegradation of aliphatics and PAHs in oil-contaminated sediments under natural field conditions in an intertidal foreshore environment. 相似文献
739.
Glyphosate-resistant (GR) soybean [Glycine max (L.) Merr.] expressing an insensitive 5-enolpyruvylshikimic acid-3-phosphate synthase (EPSPS) gene has revolutionized weed control in soybean production. The soybean nitrogen fixing symbiont, Bradyrhizobium japonicum, possesses a glyphosate-sensitive enzyme and upon exposure to glyphosate accumulates shikimic acid and hydroxybenzoic acids such as protocatechuic acid (PCA), accompanied with B. japonicum growth inhibition and death at high concentrations. In a series of greenhouse and field experiments, glyphosate inhibited nodulation and nodule leghemoglobin content of GR soybean. Glyphosate accumulated in nodules of field-grown GR soybean, but its effect on nitrogenase activity of GR soybean was inconsistent in field studies. In greenhouse studies, nitrogenase activity of GR soybean following glyphosate application was transiently inhibited especially in early growth stages, with the greatest inhibition occurring under moisture stress. Studies using bacteroid preparations showed that the level of glyphosate inhibition of bacteroid nitrogenase activity was related to in vitro glyphosate sensitivity of the B. japonicum strains. These studies indicate the potential for reduced nitrogen fixation in the GR soybean system; however, yield reductions due to this reduced N2 fixation in early stages of growth have not been demonstrated. 相似文献
740.
Application of the pressure-state-response framework to perceptions reporting of the state of the New Zealand environment 总被引:6,自引:0,他引:6
The Pressure-State-Response framework for environmental reporting was used as a basis to develop a long-term study of people's perceptions of the state of the New Zealand environment. A postal survey of 2000 people, randomly drawn from the New Zealand electoral roll was used to gather data--an effective response rate of 48% was achieved. A range of different resource sectors was examined. We report on New Zealand's air, native animals and plants, and marine fisheries, as well as New Zealand compared to other developed countries. Respondents generally considered that in terms of pressures, states and responses, New Zealand was performing better than other developed countries and that for the resources examined here overall performance was in the adequate to good range, except for marine fisheries. The survey appears to be a useful tool for linking perceptions data into State of the Environment reporting. It also helps identify policy issues where perceptions do not match other scientific evidence or management initiatives. Such findings can be important for the successful implementation of policy measures. 相似文献