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401.
贵州省碳酸盐岩地区土壤允许流失量的空间分布 总被引:13,自引:1,他引:13
根据决定上覆土层厚度的碳酸盐岩建造中的泥质含量,贵州碳酸盐岩地区的岩石组合类型可分为连续性碳酸盐岩组合、碳酸盐岩夹碎屑岩组合、碳酸盐岩与碎屑岩互层组合,按贵州碳酸盐岩的风化溶蚀速率平均值49.67 mm/ka计算了碳酸盐岩不同岩石组合类型的成土速率,并以此作为相应岩石类型地区的土壤允许流失量。连续性碳酸盐岩组合地区土壤允许流失量小于6.84 t/(km2.a),为土壤侵蚀极度敏感区;碳酸盐岩夹碎屑岩组合地区土壤允许流失量小于45.53 t/(km2.a),为土壤侵蚀重度敏感区;碳酸盐岩与碎屑岩互层组合地区土壤允许流失量小于103.46 t/(km2.a),为土壤侵蚀中度敏感区。说明贵州碳酸盐岩地区的土壤侵蚀分级标准存在空间分异。强度石漠化主要分布在土壤允许流失量小于6.84 t/(km2.a)的连续性碳酸盐岩地区,尤其是连续性石灰岩地区分布最广。 相似文献
402.
康纪田 《中国环境管理干部学院学报》2010,20(6):19-24
矿业环境相邻关系的界定是相应环境产权私人化的途径。由矿业环境相邻权与矿业成员环境权双向对接组成的环境相邻关系,通过法律来约束矿山企业的环境相邻权和激励相邻对方的成员环境权而共同保护矿业环境。矿山企业一方给相邻对方合理施加容忍义务,相邻对方应当容忍非实质性的或当地通行的影响。成员环境权的保护,是基于物权而行使消除危险、排除妨害和恢复原状的请求权,基于债权而行使侵害赔偿请求权。 相似文献
403.
404.
人工神经网络结构对径流预报精度的影响分析 总被引:15,自引:0,他引:15
建立了基于径流形成机理的以时段降水量与前期径流量为预报因子的前向多层人工神经网络径流预报模型;分析了网络结构对月径流预报精度的影响,发现随网络结构的复杂化,网络训练误差减小,模型评定的确定性系数增大,并均趋于稳定,预报检验的确定性系数总趋势是减小;发现影响模型精度的决定因素是网络输入单元数,亦即径流影响因素;提出了以模型评定与预报检验共同高效或等效的模型选择的折衷方法,以及按模型适宜预报域进行多模型组合预报的最佳预报域组合法。 相似文献
405.
海洋耐镉微生物筛选及其生物学特性 总被引:1,自引:0,他引:1
从重金属污染的近海域筛选到一株对镉具有较强抗性和富集能力的微生物Cd20002,该菌株在液体培养基中的最大耐受浓度为1 000 mg/L,在镉浓度达到200 mg/L时,其吸附率高达93.4%,根据形态特征和生理生化鉴定及16S rRNA测序鉴定为蓝杆菌。通过在不同的镉浓度环境对蓝杆菌Cd20002进行培养,测定其生长曲线,并优化菌体生长的条件及其吸附能力。结果表明,蓝杆菌Cd20002既能在重金属镉环境中生存,且富镉能力较强,对水产环境中重金属的生物清排具有重要意义。 相似文献
406.
芽孢杆菌制剂广泛应用于畜禽养殖和粪污处理等领域,铜作为饲料添加剂用于畜禽养殖,导致畜禽粪便中大量残留,在此压力下芽孢杆菌等会产生铜耐受性,由于芽孢杆菌的抗逆性,这种耐受性可由可移动遗传元件介导在环境中传播.本研究采集了多个规模化养殖场的牛粪、鸡粪和猪粪,从粪便中分离芽孢杆菌,通过PCR技术、最小抑菌浓度测定和全基因组测序方法,了解畜禽粪便中芽孢杆菌对铜耐受性.研究发现:(1)分离出芽孢杆菌属23种芽孢杆菌共235株.分离数量前三分别是枯草芽孢杆菌(Bacillus subtilis)77株,占总数的32.77%;蜡样芽孢杆菌(B.cereus)31株,占比13.19%;贝莱斯芽孢杆菌(B.velezensis)28株,占比11.91%.(2)芽孢杆菌对铜耐受表型和基因型研究发现,铜对芽孢杆菌的MIC集中在200~400 mg·L-1,占总数235株的77.87%(n=183),铜耐受能力较高的菌株能够达到500~600 mg·L-1,占总数的16.17%(n=38),5株MIC达到600 mg·L-1的菌株全部来自于猪粪... 相似文献
407.
This paper reports a field investigation of interactions between juveniles and their mothers in the Australian sleepy lizard,
Tiliqua rugosa. In their first spring season, juvenile lizards maintain home ranges largely within the home range of their mother. Juvenile
home ranges are significantly smaller than those of adult males and females, and juveniles move significantly less often and
significantly shorter distances than adults. While siblings were never found together in the spring, they showed a significant
tendency to be closer to each other than if they were randomly located in their home ranges. Juveniles and mothers were never
found together, nor was there any evidence for any positive (or negative) spatial association. Nevertheless, the extended
tolerance of home range overlap represents a greater degree of mother-offspring association than has been previously reported
for other lizards. Despite this, the level of parental care can only be described as minimal.
Received: 20 June 1997 / Accepted after revision: 29 December 1997 相似文献
408.
Little EE Calfee RD Theodorakos P Brown ZA Johnson CA 《Environmental science and pollution research international》2007,14(5):333-337
Background Cobalt cyanide complexes often result when ore is treated with cyanide solutions to extract gold and other metals. These have
recently been discovered in low but significant concentrations in effluents from gold leach operations. This study was conducted
to determine the potential toxicity of cobalt-cyanide complexes to freshwater organisms and the extent to which ultraviolet
radiation (UV) potentiates this toxicity. Tests were also conducted to determine if humic acids or if adaptation to UV influenced
sensitivity to the cyanide complexes.
Methods Rainbow trout (Oncorhynchus mykiss), Daphnia magna, and Ceriodaphnia dubia were exposed to potassium hexacyanocobaltate in the presence and absence of UV radiation, in the presence and absence of
humic acids. Cyano-cobalt exposures were also conducted with C. dubia from cultures adapted to elevated UV.
Results With an LC50 concentration of 0.38 mg/L, cyanocobalt was over a 1000 times more toxic to rainbow trout in the presence of
UV at a low, environmentally relevant irradiance level (4 μW/cm2 as UVB) than exposure to this compound in the absence of UV with an LC50 of 112.9 mg/L. Toxicity was immediately apparent,
with mortality occurring within an hour of the onset of exposure at the highest concentration. Fish were unaffected by exposure
to UV alone. Weak-acid dissociable cyanide concentrations were observed in irradiated aqueous solutions of cyanocobaltate
within hours of UV exposure and persisted in the presence of UV for at least 96 hours, whereas negligible concentrations were
observed in the absence of UV. The presence of humic acids significantly diminished cyanocobalt toxicity to D. magna and reduced mortality from UV exposure. Humic acids did not significantly influence survival among C. dubia. C. dubia from UV-adapted populations were less sensitive to metallocyanide compounds than organisms from unadapted populations.
Conclusions The results indicate that metallocyanide complexes may pose a hazard to aquatic life through photochemically induced processes.
Factors that decrease UV exposure such as dissolved organic carbon or increased pigmentation would diminish toxicity. 相似文献
409.
410.