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971.
Several immunosuppressive factors are associated with parasitism of an endoparasitoid wasp, Cotesia plutellae, on the diamondback moth, Plutella xylostella. C. plutellae bracovirus (CpBV) encodes a large number of putative protein tyrosine phosphatases (PTPs), which may play a role in inhibiting
host cellular immunity. To address this inhibitory hypothesis of CpBV-PTPs, we performed transient expression of individual
CpBV-PTPs in hemocytes of the beet armyworm, Spodoptera exigua, and analyzed their cellular immune responses. Two different forms of CpBV-PTPs were chosen and cloned into a eukaryotic
expression vector under the control of the p10 promoter of baculovirus: one with the normal cysteine active site (CpBV-PTP1)
and the other with a mutated active site (CpBV-PTP5). The hemocytes transfected with CpBV-PTP1 significantly increased in
PTP activity compared to control hemocytes, but those with CpBV-PTP5 exhibited a significant decrease in the PTP activity.
All transfected hemocytes exhibited a significant reduction in both cell spreading and encapsulation activities compared to
control hemocytes. Co-transfection of CpBV-PTP1 together with its double-stranded RNA reduced the messenger RNA (mRNA) level
of CpBV-PTP1 and resulted in recovery of both hemocyte behaviors. This is the first report demonstrating that the polydnaviral
PTPs can manipulate PTP activity of the hemocytes to interrupt cellular immune responses. 相似文献
972.
973.
974.
Formaldehyde (HCHO) is toxic to the human body and is one of the main threats to the indoor air quality (IAQ). As such, the removal of HCHO is imperative to improving the IAQ, whereby the most useful method to effectively remove HCHO at room temperature is catalytic oxidation. This review discusses catalysts for HCHO room-temperature oxidation, which are categorized according to their preparation methods, i.e., gas-phase reduction and liquid-phase reduction methods. The HCHO oxidation performances, structural features, and reaction mechanisms of the different catalysts are discussed, and directions for future research on catalytic oxidation are reviewed. 相似文献
975.
Sulfur deposition simulations over China, Japan, and Korea: a model intercomparison study for abating sulfur emission 总被引:1,自引:1,他引:0
Cheol-Hee Kim Lim-Seok Chang Fan Meng Mizuo Kajino Hiromasa Ueda Yuanhang Zhang Hye-Young Son Jong-Jae Lee Youjiang He Jun Xu Keiichi Sato Tatsuya Sakurai Zhiwei Han Lei Duan Jeong-Soo Kim Suk-Jo Lee Chang-Keun Song Soo-Jin Ban Shang-Gyoo Shim Young Sunwoo Tae-Young Lee 《Environmental science and pollution research international》2012,19(9):4073-4089
In response to increasing trends in sulfur deposition in Northeast Asia, three countries in the region (China, Japan, and Korea) agreed to devise abatement strategies. The concepts of critical loads and source?Creceptor (S?CR) relationships provide guidance for formulating such strategies. Based on the Long-range Transboundary Air Pollutants in Northeast Asia (LTP) project, this study analyzes sulfur deposition data in order to optimize acidic loads over the three countries. The three groups involved in this study carried out a full year (2002) of sulfur deposition modeling over the geographic region spanning the three countries, using three air quality models: MM5-CMAQ, MM5-RAQM, and RAMS-CADM, employed by Chinese, Japanese, and Korean modeling groups, respectively. Each model employed its own meteorological numerical model and model parameters. Only the emission rates for SO2 and NOx obtained from the LTP project were the common parameter used in the three models. Three models revealed some bias from dry to wet deposition, particularly the latter because of the bias in annual precipitation. This finding points to the need for further sensitivity tests of the wet removal rates in association with underlying cloud?Cprecipitation physics and parameterizations. Despite this bias, the annual total (dry plus wet) sulfur deposition predicted by the models were surprisingly very similar. The ensemble average annual total deposition was 7,203.6?±?370 kt S with a minimal mean fractional error (MFE) of 8.95?±?5.24?% and a pattern correlation (PC) of 0.89?C0.93 between the models. This exercise revealed that despite rather poor error scores in comparison with observations, these consistent total deposition values across the three models, based on LTP group's input data assumptions, suggest a plausible S?CR relationship that can be applied to the next task of designing cost-effective emission abatement strategies. 相似文献
976.
Kim YS Jeong CS Seong GT Han IS Lee YS 《Journal of environmental biology / Academy of Environmental Biology, India》2010,31(5):687-693
The diurnal vertical migration of Cochlodinium polykrikoides (C. polykrikoides), which caused a red tide in the Korean coastal waters of the East Sea/Sea of Japan in September 2003, was examined by determining the time-dependent changes in the density of living cells in relation to the depth of the water column. The ascent of this species into the surface layer (depth of water 2 m) occurred during 1400-1500. The descent started at 1600 and a high distribution rate (86%) at 15-20 m was observed at 0300. During the ascent, the cells were widely distributed at each depth level from 0600 hr and at 0800-1100, the cells were primarily distributed in the middle layer (0-6 m). The concentration of dissolved inorganic nitrogen was generally < or = 2.86 micromol l(-1), but at 1400-1500, the concentration in the surface layer reduced to < or = 0.14 micromol l(-1). Moreover, the concentration gradually increased as the depth increased to > or = 5 m. These results showed that the nutrient-consumption rate associated with the proliferation of C. polykrikoides during a red tide is more influenced by the inorganic-nitrogen resources ratherthan the inorganic-phosphorus compounds. 相似文献
977.
Kitirote Wantala Suthipong Sthiannopkao Bang-orn Srinameb Nurak Grisdanurak Kyoung Woong Kim 《Environmental geochemistry and health》2010,32(4):261-266
Rice husk (RH) agro-waste was used as a raw material for synthesizing mesoporous molecular sieves, MCM-41. The Fe-MCM-41 was
prepared by the hydrothermal technique (HT), resulting in a higher surface area and crystallinity than when prepared under
ambient conditions. In addition, a hexagonal structure was clearly seen with hydrothermal technique (HT) preparation. The
adsorption of arsenate by HT-Fe-MCM-41 was investigated. The factors studied affecting arsenate adsorption capacity were ferric
content in MCM-41, contact time, pH of solution, and initial arsenate concentration. It was found that HT-Fe-MCM-41 at the
Si/Fe mole ratio of 10 gave the highest adsorption capacity. Arsenate adsorption reached equilibrium within 4 h. The adsorption
capacity of HT-Fe-MCM-41 (Si/Fe = 10) was affected by the initial pH value and the initial arsenate concentration. The adsorption
capacity was highest at pH 3 and decreased thereafter with increases in the pH of solution value. The Langmuir model fit the
arsenate adsorption isotherm well. The maximum adsorption capacity for arsenate was 1,111 μg g−1. 相似文献
978.
Myoung-Soo Ko Hyun-Sung Park Kyoung-Woong Kim Jong-Un Lee 《Environmental geochemistry and health》2013,35(6):727-733
Bioleaching of As from the soil in an abandoned Ag–Au mine was carried out using Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. A. ferrooxidans is an iron oxidizer and A. thiooxidans is a sulfur oxidizer. These two microbes are acidophilic and chemoautotrophic microbes. Soil samples were collected from the Myoungbong and Songcheon mines. The main contaminant of the soil was As, with an average concentration of 4,624 mg/kg at Myoungbong and 5,590 mg/kg at Songcheon. A. ferrooxidans and A. thiooxidans generated lower pH conditions during their metabolism process. The bioleaching of As from soil has a higher removal efficiency than chemical leaching. A. ferrooxidans could remove 70 % of the As from the Myoungbong and Songcheon soils; however, A. thiooxidans extracted only 40 % of the As from the Myoungbong soil. This study shows that bioleaching is an effective process for As removal from soil. 相似文献
979.
This survey aimed to compare mercury concentrations in soils related to geology and mineralization types of mines. A total of 16,386 surface soils (0~15 cm in depth) were taken from agricultural lands near 343 abandoned mines (within 2 km from each mine) and analyzed for Hg by AAS with a hydride-generation device. To meaningfully compare mercury levels in soils with geology and mineralization types, three subclassification criteria were adapted: (1) five mineralization types, (2) four valuable ore mineral types, and (3) four parent rock types. The average concentration of Hg in all soils was 0.204 mg kg(-1) with a range of 0.002-24.07 mg kg(-1). Based on the mineralization types, average Hg concentrations (mg kg(-1)) in the soils decreased in the order of pegmatite (0.250) > hydrothermal vein (0.208) > hydrothermal replacement (0.166) > skarn (0.121) > sedimentary deposits (0.045). In terms of the valuable ore mineral types, the concentrations decreased in the order of Au-Ag-base metal mines ≈ base metal mines > Au-Ag mines > Sn-W-Mo-Fe-Mn mines. For parent rock types, similar concentrations were found in the soils derived from sedimentary rocks and metamorphic rocks followed by heterogeneous rocks with igneous and metamorphic processes. Furthermore, farmland soils contained relatively higher Hg levels than paddy soils. Therefore, it can be concluded that soils in Au, Ag, and base metal mines derived from a hydrothermal vein type of metamorphic rocks and pegmatite deposits contained relatively higher concentrations of mercury in the surface environment. 相似文献
980.
Arild?Johnsen Kim?L.?Carter Kaspar?Delhey Jan?T.?Lifjeld Raleigh?J.?Robertson Bart?KempenaersEmail author 《Behavioral ecology and sociobiology》2012,66(2):181-190
In birds, the number of sperm trapped between the perivitelline membranes around the ovum is an estimate of sperm numbers
present at the time and place of fertilisation in the female reproductive tract. Sperm numbers may vary among species and
between eggs in a clutch and can provide information about sperm utilisation and mechanisms of sperm competition. Here, we
describe patterns of variation in sperm numbers through the egg-laying sequence in three passerines in which extra-pair paternity
is common, but copulation behaviour differs. Sperm numbers showed no systematic change across the laying sequence in blue
tits (Cyanistes caeruleus), but decreased significantly with laying order in bluethroat (Luscinia svecica) and tree swallow (Tachycineta bicolor) clutches. This is consistent with observations that blue tits regularly copulate throughout the laying sequence, while bluethroats
stop mate guarding and tree swallows reduce their copulation frequency once the first egg is laid. Nevertheless, cases of
a sudden increase in sperm numbers in clutches of bluethroats and tree swallows suggest that successful inseminations also
occurred after laying started. In blue tits and bluethroats, sperm numbers were not higher on extra-pair sired eggs than on
eggs sired by the social male, suggesting that extra-pair copulations are not timed to the period of peak fertility for each
egg. More extra-pair offspring originated from eggs laid early in the sequence in blue tits, while there was no systematic
bias in bluethroats. Our results suggest that copulations during the laying sequence are predominantly performed by within-pair
males in our study species. 相似文献