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151.
Figueroa JA Wrobel K Afton S Caruso JA Corona Felix Gutierrez J Wrobel K 《Chemosphere》2008,70(11):2084-2091
Phytochelatins (PCs) were determined in the wild plants, focusing on their relationship with the levels of heavy metals and humic substances (HS) in soil. Ricinus communis and Tithonia diversifolia were collected from several sites in Guanajuato city (Mexico), which had long been the silver and gold mining center. The analysis of PCs in root extracts was carried out by liquid chromatography (derivatization with monobromobimane). Total Ag, Cd, Cu and Pb in plant roots and in soil samples, as well as soil HS were determined. The association of metals with HS in soils was evaluated by size exclusion chromatography (SEC) with UV and ICP-MS detection. The results obtained revealed the induction of PCs in R. communis but not in T. diversifolia. The levels of Cd and Pb in plant roots presented strong positive correlation with PC-2 (r = 0.9395, p = 0.005; r = 0.9573, p = 0.003, respectively), indicating that these two metals promote PCs induction in R. communis. On the other hand, the inverse correlation was found between soil HS and metal levels in roots of R. communis (Cu > Pb > Cd > Ag), in agreement with the decreasing affinity of these metals to HS. Importantly, the inverse correlation between soil HS and plant PC-2 was observed (r = −0.7825, p = 0.066). These results suggest that metals strongly bound to HS could be less bioavailable to plants, which in turn would limit their role in the induction of PCs. Indeed, the SEC elution profiles showed Pb but not Cd association with HS and the correlation between metal in soil and PC-2 in plant was statistically significant only for Cd (r = 0.7857, p = 0.064). Based on these results it is proposed that the role of heavy metals in PCs induction would depend on their uptake by R. communis, which apparently is controlled by the association of metals with soil HS. This work provides further evidence on the role of environmental conditions in the accumulation of heavy metals and phytochelatin production in plants. 相似文献
152.
Yifat Ochshorn Michael J. Kupferminc Amiram Eldor Igal Wolman Joseph B. Lessing Yuval Yaron 《黑龙江环境通报》2001,21(8):658-661
Obstetric complications, such as severe pre-eclampsia, fetal growth restriction, abruptio placentae, or stillbirth are associated with abnormally elevated second-trimester maternal serum alpha-fetoprotein (MSAFP) and β subunit of human chorionic gonadotrophin (βhCG). This has been attributed to placental abnormalities. Women with thrombophilias have been shown to have abnormalities of the placenta resulting in adverse pregnancy outcome in these patients. The purpose of the present study was to evaluate whether women with pregnancy complications and inherited thrombophilias have abnormally elevated second-trimester MSAFP or βhCG. Sixty-two women with pregnancy complications were tested for inherited thrombophilias several months after delivery. The thrombophilia group included 29 women with pregnancy complications and an inherited thrombophilia and the control group included 33 other patients without thrombophilia. Patients in the thrombophilia group had a higher median MoM MSAFP compared to the controls (1.337 vs 1.086, p=0.0516). The incidence of abnormally elevated MSAFP (>2.5 MoM) was also significantly higher in the thrombophilia group compared to controls (21% vs 3%, p=0.04). Neither the median MoM βhCG nor the incidence of abnormally elevated βhCG were significantly different between the groups. We conclude that second trimester MSAFP, but not βhCG, is abnormally elevated in patients with thrombophilia and obstetric complications. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
153.
154.
The distribution of three important dissolved forms of nitrogen, viz. nitrate, nitrite and urea in the surface and bottom water samples collected from 27 selected hydrographic profiles, in the Arabian Sea, along the west coast of India is described. Of the three forms, nitrate concentrations were the highest and comparatively higher concentrations were observed in the bottom water. Decomposition of organic matter resulting in the release of the thermodynamically stable nitrogen species, i.e. nitrate, may be the major factor resulting in higher nitrate concentrations at these depths, where the water is also characterized by low values of dissolved oxygen and temperature. The significant positive correlation between A.O.U. and nitrate of the bottom water samples emphasizes the role of oxidative decomposition of organic matter which plays an active role in reducing the oxygen concentrations below the theoretical values since at this depth ( ≈200 m) the net production is taken to be zero. This is also evidenced by the negative correlation of nitrate with dissolved oxygen and temperature, for the bottom samples. 相似文献
155.
156.
Kathryn D. McGowan Joseph J. Weiser Juli Horwitz Sue Ann Berend Christopher McCaskill V. Reid Sutton Lisa G. Shaffer 《黑龙江环境通报》2002,22(2):141-143
We report the finding of paternal isodisomy for chromosome 14 in a fetus found to have a der(14;14)(q10;q10) by amniocentesis. The pregnancy was complicated by severe polyhydramnios and elevated amniotic fluid alpha-fetoprotein (AFP). The infant showed features consistent with paternal uniparental disomy (UPD) including postnatal growth retardation, poor respiratory function, feeding difficulties, and evidence of hypertrophic cardiomyopathy. The present case, in addition to other reported cases of UPD involving balanced acrocentric rearrangements, supports testing for UPD in prenatally detected Robertsonian translocations and isochromosomes. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
157.
158.
Influential factors in freeway crash response and clearance times by emergency management services in peak periods 总被引:1,自引:0,他引:1
OBJECTIVE: Various factors influence the time performance of emergency management personnel when a freeway traffic crash occurs. The proper identification and prioritization of factors that contribute to emergency management services' response times and clearance times result in better usage of taxpayer resources. METHOD: Use of a proportional hazard-based Cox-regression model analyzed statewide, peak-period, traffic crash data from 1999 Ohio logs. These data included time performance measures of emergency management services. RESULTS: Traffic crash severity had the most effect on response times. Those crashes involving injuries or fatalities had up to 20% less emergency management service response times than "property damage only" crashes. Environmental factors such as weather or roadway conditions had minimal effect on response times to traffic crashes. Day of week, urban or rural area, off or opposing-lane crash location, number of vehicles involved, heavy vehicle involvement, and response time significantly affected clearance time and the resulting total time during peak periods. CONCLUSIONS: By assessing resources currently dedicated to insignificant factors, emergency management services can further improve response times to those casualties that crucially need emergency services. By accurately identifying and deciphering traffic crash severity from initial field reports, services can further improve. Moreover, improvements in crash severity prediction reduce "false alarms" for emergency services. The improvements reduce the probability of a very short response time for a property damage only crash in which initial reports implied a very severe injury. By focusing on factors that significantly reduce traffic crash clearance times on freeways in peak periods, more reductions in average delay experienced by freeway users, in fuel consumption, and in motor vehicle emissions can occur. 相似文献
159.
Joseph L. Horowitz Mark D. Shulman 《Journal of the American Water Resources Association》1967,3(2):19-31
A comparative evaluation is made of the frequency of air mass and frontal types during a 4-year representative portion of the drought as opposed to an equivalent non-drought period. Selection of the non-drought period is based on the Palmer Drought Index. Results indicate a statistically significant increase in the occurrence of continental polar air during the drought. Other conclusions concerning conditions during the drought, not statistically significant but worth further study, are: lower frequency of maritime tropical air in the summer months, more occurrences of cold and occluded fronts, and fewer occurrences of stationary fronts. 相似文献
160.
Joseph M. Perez 《Environment international》1981,5(4-6)
Development of analytical capabilities to evaluate unregulated emissions are discussed. The sampling and analysis methods along with some problem areas are included. Results obtained on three heavy-duty diesel engines are reported. Emphasis was placed on analysis of the particulate fraction including the solvent extractable material. Preliminary experiments suggest appreciable quantities of organic extract and BaP pass through the primary filter. Other species analyzed to obtain a baseline for emission reduction research included aldehydes, sulfates, sulfur dioxide, ammonia, hydrogen sulfide, and hydrogen cyanide. Of primary concern is the proper assessment of the results. 相似文献