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991.
L. P. Zhao W. Cui X. Bai Z. B. Wang J. M. Cheng P. Sun F. R. Zhao 《Russian Journal of Ecology》2017,48(6):551-558
To understand the effects of different disturbance regimes on the bud bank demography in perennial grasslands, we conducted a demographic field investigation of the bud bank in a typical steppe on the Loess Plateau. Grazing significantly decreased and fire significantly increased bud bank density compared to fenced grasslands. For different bud bank types, grazing significantly decreased tiller bud bank density, and fire significantly increased the density of root crown buds and rhizomatous buds in relation to fenced grasslands. Tiller buds accounted for the majority of the total bud banks independently of the disturbance regimes. Our study suggests that the grasslands with a large reserve bud bank may be the most resistant to disturbance, and fencing is an effective grassland management measure to keep a large bud bank in typical steppe on the Loess Plateau. 相似文献
992.
Weihai Xu Wen Yan Gan Zhang Jun Li Li Miao Weixia Huang 《Environmental science and pollution research international》2014,21(14):8774-8781
Oceans play a significant role in the cycling of trace metals and persistent organic pollutants. In this study, aerosol samples covering the whole northern South China Sea (SCS) were collected in 2005 and 2007, respectively, for analysis of trace metals and major elements. The levels of trace metals detected ranged from 0.514 to 119 ng/m3 in 2005 and from 0.130 to 24.2 ng/m3 in 2007, respectively. Cu, Zn, and Pb were the three predominant metals with high enrichment factors (>10), indicating the strong anthropogenic inputs. The trace metals over SCS were comparable to the values in suburban and background sites of South China, but generally higher than those over other seas and oceans. Considering the fact that they were influenced by their proximity to source regions and air mass origins, the elevated metals in 2005 were probably attributed to the strong wind and long-range atmospheric transport driven by Asian monsoon. 相似文献
993.
Hao Wang Lihong Mu Miao Jiang Yingxiong Wang Wei Yan Yongzhuo Jiao 《Environmental monitoring and assessment》2014,186(4):2081-2088
To study the relationship between chemical elements in soil and whole blood, and fluorosis induced by coal-fired pollution, ecological and case–control studies were carried out. We determined the concentrations of 11 chemical elements and pH values in soil in two fluorosis-affected counties in Chongqing, China, and analyzed the correlation between these values and prevalence of dental fluorosis. Ni, I, F, Hg, and pH values positively correlated with fluorosis prevalence (P?<?0.05); these soil parameters may be related to coal-fired pollution fluorosis. Cu, Zn, Ca, Mg, and Fe concentrations in whole blood, and fluoride levels in urine of residents in epidemic and non-epidemic areas were determined. Cu, Zn, Mg, and Fe levels of the children in the case group were lower than those of the children in the external control group; urine fluoride level in the children in the case group was higher than that of the children in the internal and external control groups (P?<?0.05). The levels of Mg, Fe, and urine fluoride were higher in the case adult group than in the internal adult control group (P?<?0.05). Anti-fluoride elements were deficient in endemic areas. 相似文献
994.
Z. S. Khan N. B. Ingale S. K. Omanwar 《Environmental science and pollution research international》2016,23(10):9295-9302
Rare earth (Dy3+ and Sm3+)-doped sodium magnesium borate (NaMgBO3) is synthesized by solution combustion synthesis method keeping their thermoluminescence properties in mind. The reaction produced very stable crystalline NaMgBO3:RE (RE?=?Dy3+, Sm3+) phosphors. The phosphors are exposed to 60Co gamma-ray radiations dose of varying rate from 5 to 25 Gy, and their TL characteristics with kinetic parameters are studied. NaMgBO3:Dy3+ phosphor shows two peaks for lower doping concentration of Dy3+ while it reduced to single peak for the higher concentrations of activator Dy3+. NaMgBO3:Dy3+ shows the major glow peak around 200 °C while NaMgBO3:Sm3+ phosphors show two well-separated glow peaks at 200 and 332 °C respectively. The thermoluminescence intensity of these phosphors was compare with the commercially available TLD-100 (Harshaw) phosphor. The TL responses for gamma-ray radiations dose were found to be linear from 5 to 25 Gy for both phosphors while the fading in each case is calculated for the tenure of 45 days. 相似文献
995.
Fyllas Nikolaos M. Christopoulou Anastasia Galanidis Alexandros Michelaki Chrysanthi Z. Giannakopoulos Christos Dimitrakopoulos Panayiotis G. Arianoutsou Margarita Gloor Manuel 《Regional Environmental Change》2017,17(4):1165-1177
Regional Environmental Change - The Mediterranean Basin is expected to face warmer and drier conditions in the future, following projected increases in temperature and declines in precipitation.... 相似文献
996.
Our case study revealed that organization of the studied local assemblages is dominated by mechanisms uniform globally, from which in Central-Europe (1) vegetation height, (2) overall vegetation cover, (3) cover of the dicotyledonous and mesophilous monocotyledonous species, (4) microclimate, (5) annual rainfall and (6) insolation in April have main importance. Life-form- and ecotype-structure of the assemblages in habitats characterized by similar vegetation-structure and microclimate seem to be conservative at Eurasian scale, but species-composition of the local variants is determined by individual effects of zoogeography, landscape structure, landuse and habitat-history. 相似文献
997.
E. Garcia-Anton S. Cuezva V. Jurado E. Porca A. Z. Miller A. Fernandez-Cortes C. Saiz-Jimenez S. Sanchez-Moral 《Environmental science and pollution research international》2014,21(1):473-484
Altamira Cave (north of Spain) contains one of the world's most prominent Paleolithic rock art paintings, which are threatened by a massive microbial colonization of ceiling and walls. Previous studies revealed that exchange rates between the cave and the external atmosphere through the entrance door play a decisive role in the entry and transport of microorganisms (bacteria and fungi) and nutrients to the interior of the cave. A spatial-distributed sampling and measurement of carrier (CO2) and trace (CH4) gases and isotopic signal of CO2 (δ13C) inside the cave supports the existence of a second connection (active gas exchange processes) with the external atmosphere at or near the Well Hall, the innermost and deepest area of the cave. A parallel aerobiological study also showed that, in addition to the entrance door, there is another connection with the external atmosphere, which favors the transport and increases microorganism concentrations in the Well Hall. This double approach provides a more complete knowledge on cave ventilation and revealed the existence of unknown passageways in the cave, a fact that should be taken into account in future cave management. 相似文献
998.
E. V. Shuyskaya E. V. Li Z. F. Rahmankulova N. A. Kuznetsova K. N. Toderich P. Yu. Voronin 《Russian Journal of Ecology》2014,45(3):181-187
The seedlings of Haloxylon aphyllum from seeds with different genetic characteristics, which were collected in three natural subpopulations along a soil salinity gradient, were investigated. The plants grown under various levels of NaCl (0–300 mM) differed in the shoot length, the relative growth rate (calculated for fresh and dry biomass), as well as ions and proline contents. The heterozygous genotypes of xerohalophytic H. aphyllum have shown significant advantages in their productivity and sustainability under moderate and high salinity. 相似文献
999.
A. Murad X. D. Zhou P. Yi D. Alshamsi A. Aldahan X. L. Hou Z. B. Yu 《Environmental monitoring and assessment》2014,186(10):6157-6167
Groundwater is the most valuable resource in arid regions, and recognizing radiological criteria among other water quality parameters is essential for sustainable use. In the investigation presented here, gross-α and gross-β were measured in groundwater samples collected in the south-eastern Arabian Peninsula, 67 wells in Unite Arab Emirates (UAE), as well as two wells and one spring in Oman. The results show a wide gross-α and gross-β activities range in the groundwater samples that vary at 0.01~19.5 Bq/l and 0.13~6.6 Bq/l, respectively. The data show gross-β and gross-α values below the WHO permissible limits for drinking water in the majority of the investigated samples except those in region 4 (Jabel Hafit and surroundings). No correlation between groundwater pH and the gross-α and gross-β, while high temperatures probably enhance leaching of radionuclides from the aquifer body and thereby increase the radioactivity in the groundwater. This conclusion is also supported by the positive correlation between radioactivity and amount of total dissolved solid. Particular water purification technology and environmental impact assessments are essential for sustainable and secure use of the groundwater in regions that show radioactivity values far above the WHO permissible limit for drinking water. 相似文献
1000.