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71.
文章选取了《联合国防治荒漠化公约》和《中华人民共和国防沙治沙法》作为比较对象,从立法背景、性质、基本结构、基本内容等角度对二者进行了比较,并指出了二者的特有之处。从而分析国内法律和国际法律的不同,并提供了我国防治沙漠化中如何借鉴好的做法,并结合自身的实际情况加以吸收的途径。  相似文献   
72.
1INTRODUCTION Human Capital Theory(HCT)'s idea origin recalls westernclassical political economics in the eighteen century.HCTcame into being in the middle and later periods of the20century,sprang up in the1960s and1970s,was introducedinto China in the1980s and is still one of the hotspotsin economic research.Foreign and domestic scholars havemade a lot of deep researches and important achievements.2FOREIGN RESEARCHIn the1950s,facing many"economic enigma"such as"Solow residual"an…  相似文献   
73.
Promoting stoves that burn wood and other biofuels more efficiently is one of the means to reduce fuel consumption, but such efficient stoves may also emit more carbon monoxide and total suspended particulates. In an earlier study, a standard chamber method was proposed to estimate emission factors from burning fuelwood (Acacia nilotica). Here that methodology is extended to measure emission factors from burning of dungcakes and crop residues (Brassica or mustard stalks)—common fuels in many developing countries. The amounts of carbon monoxide (CO) and total suspended particulates (TSP) emitted by four different models of stoves, when using each of the three biofuels, are measured.The CO emission factors range from 13–68 (g/kg) for fuelwood to 26–67 g/kg for dungcakes and 20–114 g/kg for crop residues, for particulates they range from 1.1–3.8 to 4.1–7.8 and 2.1–12.0 g/kg for the three fuels, respectively. On a per unit heat delivered basis, the emissions of CO and TSP from both dungcakes and crop residues are two to three times higher compared to those from fuelwood. While for some improved stove-fuel combinations, the increase in emission factors was offset by the increase in thermal efficiency, this was not always so and causes a dilemma. The more efficient stoves are found to have higher emission factors of both CO and TSP for all three fuels. Emissions per standard task (i.e, on a unit heat delivered basis) is proposed as a criterion to evaluate cookstoves.  相似文献   
74.
ABSTRACT: The income and proce elasticity of demand for domestic water is estimated for Penang Island, Malaysia. A cross-sectional analysis of a random sample of 1400 households indicated an income-elasticity of zero for low-income families (per capita income less than US$300) and an elasticity of 0.2-0.4 for higher-income families. A time-series analysis of a subsample of individuals of varying income levels suggests a short-run price elasticity of -0.1 to -0.2. The implications of these results for demand forecasting are discussed.  相似文献   
75.
In developing countries, planning in the forestry sector has been seen as an appropriate instrument to prepare and implement government policies and programs. Despite its potential and recent advancements in, for example, remote sensing and infrastructure, tropical forest land-use planning is often formal and non-integrated with agriculture. It rarely involves all legitimate stakeholders and neglects taking into account actual land-use. The socio-economic and environmental consequences of these shortcomings emphasise the need for alternative ways of approaching planning. This article summarises the idea, structure and current status of the Area Production Model (APM), originally developed in the 1980s, which is now gaining interest as a land-use planning tool in Africa and Asia. It describes the development over time of production and consumption in agriculture and forestry within a defined geographical area operating under different assumptions on management, land use and socio-economic and macro-economic changes. From a narrow perspective, the APM is a fairly simple computerised tool for generating scenarios. In a broad sense, it is a concept comprising the whole planning process including organisation, inventory, data analysis, consensus building and strategy. A case-study in Laos, based on verified data for a historical period of 45 years, and a review of different APM applications in the world over the last 15 years are presented as a base for conclusions about its potential and shortcomings. In some cases where the APM concept was used in training courses and planning exercises involving stakeholders, it generated a strong interest in collecting and analysing relevant information. It provides the means of addressing a number of shortcomings in current planning.  相似文献   
76.
“一带一路”沿线国家是世界重要粮食生产—消费区,开展该区域粮食安全研究具有重要意义。聚焦粮食消费,剖析沿线国家1995—2017年粮食消费时空格局特征,揭示影响因素。结果表明:(1)1995—2017年,粮食消费数量逐渐增长,总量占世界比例介于55%~59%,人均消费量增至367 kg,为世界水平的95%。(2)1995—2017年,其他用粮和工业用粮高速增长,饲料和口粮快速增长,损耗和种子用粮缓慢增长,形成“口粮为主、饲料为辅”的消费结构,处于粮食消费初级阶段。(3)消费总量空间差异大而人均消费差异小,中东欧国家消费水平高,人口大国、岛屿小国、粮食生产条件欠佳国家消费水平较低。(4)各类用途粮食人均消费量空间差异不大,饲料总量空间差异最大且逐渐增大,近半数国家仍以口粮为主,约25%的国家完成了向相对均衡型转变的消费结构升级。(5)人口数量和消费水平累积贡献率约为43%和57%,中亚、东南亚、南亚多数国家受消费、人口共同影响,西亚及中东国家多受人口影响,中东欧内部差异大。口粮、饲料累积贡献量占比约为46%和34%,南亚、东南亚国家多受口粮影响,中蒙俄、中亚国家多受饲料影响,中东欧和中南半岛国家多为综合贡献型。  相似文献   
77.
Duloxetine (DUL), an antidepressant drug, has been detected in surface water and wastewater effluents, however, there is little information on the formation of its transformation products (TPs). In this work, hydrolysis, photodegradation (UV irradiation) and chlorination experiments were performed on spiked distillated water, under controlled experimental conditions to simulate abiotic processes that can occur in the environment and wastewater treatment plants (WWTPs). Eleven TPs, nine from reaction with UV light and two from chlorine contact, were formed and detected by ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry, and nine of them had their chemical structures elucidated upon analyses of their fragmentation patterns in MS/MS spectra. The formation and degradation of the TPs were observed. The parent compound was completely degraded after 30?min in photodegradation and after 24?hr in chlorination. Almost all TPs were completely degraded in the experiments. The ecotoxicity and mutagenicity of the TPs were predicted based on several in silico models and it was found that a few of these products presented more ecotoxicity than DUL itself and six TPs showed positive mutagenicity. Finally, wastewater samples were analyzed and DUL and one TP, possibly formed by chlorination process, were detected in the effluent, which showed that WWTP not only did not remove DUL, but also formed a TP.  相似文献   
78.
Rat calvarial osteoblasts were treated with lanthanum chloride (LaCl3) to explore its effect on the mineral crystalline phase during the process of osteoblast calcification in vitro. The results confirmed that La was readily deposited in the mineral component of the matrix. Employing high-resolution transmission electron microscopy and Fourier transform infrared microspectroscopy techniques, we demonstrated that features comparable to dicalcium phosphate dihydrate (DCPD) and octacalcium phosphate, and hydroxyapatite (HAP) were detected in the mineral phases in vitro. Particularly, LaCl3 treatment retarded conversion from DCPD-like phase into HAP during mineralization. In addition, La was introduced in DCPD powder during wet chemical synthesis. When compared with that of La-free DCPD, the dissolution rate of La-incorporated DCPD was lower, thereby leading to a delayed DCPD-to-HAP phase transformation. Thus, it can be concluded that LaCl3 treatment influences the kinetics of inorganic phase transition by decreasing the dissolution rate of DCPD.  相似文献   
79.
氮素在土壤-作物中迁移转化的试验研究   总被引:2,自引:0,他引:2  
为研究氮素在土壤和作物体系中的运移规律。本文开展土壤箱栽试验,分析农作物玉米在关中盆地3种不同类型土壤中对氮素的吸收以及土壤中氮素的迁移转化规律。结果表明,在试验初期,3种土壤中三氮主要以NH4+的形式存在,随着农作物生长NH4+含量减少,同时NO2-和NO3-含量均有不同程度的累积。作物收获后,土壤和作物体系中有相当数量的氮素残留,而且土壤中氮残留相对较高,导致氮素的损失率较大,流失的N素必将会对土壤、甚至地下水产生污染,因此建议该地区针对不同的土壤类型控制氮肥施用量,合理施用氮肥。  相似文献   
80.
柳州市这个“十雨九酸”的工业城市在经济升级、城市转型的过程中,完美实现了向“生态宜居”城市的战略转变。1994年国家有关部门把柳州市酸雨治理列为第四批日本海外经济协力基金贷款项目。这一项目开启城市环境治理新纪元,带动柳州经济发展方式的转变,促进柳州从“污染城市”到“创建环保模范城市”的跨越,“贷”动了柳州是从政府部门环保对策、城市环保质量到公众环保意识的全面提升,助力酸雨柳州的生态转变,在西部地区经济与环境协调发展和促进资源节约型和环境友好型工业城市发展方面具有重要的示范作用。  相似文献   
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