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1.
当前市场上的各种报警系统种类繁多,各类制造商也是比比皆是,消费者可以随心所欲地选择他们喜欢的系统。各类系统之间的差别也非常有限,下面我们来介绍一套报警设备的DIY方案,供读者参考(由Alicia示范)。 相似文献
2.
Sreedevi P Sivaramakrishna B Suresh A Radhakrishnaiah K 《Environmental pollution (Barking, Essex : 1987)》1992,77(1):59-63
Nickel has an adverse effect on some aspects of protein metabolism of the freshwater fish, Cyprinus carpio. The main changes observed were: (a) Decrease in soluble, structural and total proteins, AlAT and AAT activities with an increase in the levels of free amino acids, protease and GDH activities and ammonia in the gill and kidney at 1, 2, 3, and 4 days of exposure to a lethal concentration, 40 mg litre(-1) of nickel; (b) Increase in soluble, structural and total proteins, free amino acids and the activities of protease, AlAT, AAT and GDH with a decrease in ammonia and urea in these organs at 1, 5, 10 and 15 days of exposure to sublethal concentration, 8 mg litre(-1); (c) The magnitude in these changes increased over time with both concentrations of the metal, and was more marked in gill than in kidney. 相似文献
3.
Reynolds B Stevens PA Adamson JK Hughes S Roberts JD 《Environmental pollution (Barking, Essex : 1987)》1992,77(2-3):157-165
Data are presented demonstrating how clearfelling has changed soil and stream water aluminium chemistry. For soil waters, a strong empirical relationship was observed between inorganic aluminium (Al(inorg)) and total inorganic anion (TIA) concentrations. Before felling, chloride and sulphate accounted for the largest proportion of the TIA concentration. After felling, in soils where nitrification was active, nitrate became increasingly important. Where this led to an increase in TIA, Al(inorg) concentrations increased. Over five years, nitrate concentrations have fallen, along with TIA, resulting in a sympathetic decline in Al(inorg). Streams draining clearfelled areas initially became more acid, although chloride and sulphate concentrations decreased. Stream water nitrate concentrations increased soon after felling and remained higher than controls for up to four years. While nitrate concentrations were high, Al(inorg) remained unchanged. Subsequently, as nitrate and TIA decreased, Al(inorg) also declined to concentrations below those in the control stream. Clearfelling upland forests will not necessarily result in immediate improvements in water quality, although long-term benefits may be seen before canopy-closure of the next crop. 相似文献
4.
Skowroński T Szubińska S Jakubowski M Pawlik B 《Environmental pollution (Barking, Essex : 1987)》1992,76(2):163-167
Availability of cadmium to Synechocystis aquatilis (estimated by 109Cd sorption and cadmium toxicity-14C method) in solutions containing cadmium and complexing (KCl) or non-complexing (KNO3) salts, in the range of 0-0.5 m was investigated. Both cadmium surface adsorption and transport into the cells were lower in solutions containing cadmium chloride complexes (CdCl+, CdCl2, CdCl3-) than in those containing cadmium in the form of Cd2+. Also, cadmium toxicity in solutions of higher KCl concentrations, in which CdCl+ and CdCl2 forms predominated, was significantly limited. 相似文献
5.
Teien HC Standring WJ Salbu B Marskar M Kroglund F Hindar A 《Journal of environmental monitoring : JEM》2004,6(3):191-200
Episodic events may be critical with respect to aluminium (Al) toxicity in moderately acidified salmon rivers. The present work demonstrates that sea salt episodes enhance the toxicity of Al in acidic rivers. The documented sea salt episode (300 [micro sign]M Cl) mobilized positively charged Al species (0.4 to 1.1 [micro sign]M Al(i)), enhanced the Al accumulation on fish gills (0.9 to 10 [micro sign]mol g(-1) dw) and caused increased stress responses (6 to15 mM blood glucose) in fish. Accumulated Al on gills remained high several days after the episode. The presented results are based on a six-week field study in two tributary rivers on the west coast of Norway. Changes in the river water qualities and Al speciation were followed using in situ fractionation techniques. Al accumulation on gills and stress responses were followed for Atlantic salmon (Salmo salar) kept in tanks continually exposed to the changing water quality. The potential mobilization of Al from the two catchments was studied by extracting soils with diluted seawater (salinity of 3). To counteract Al toxicity, one of the tributary catchments has been limed. The potential mobility of Al by sea salt was lower in limed soils compared to acid soils, and the Al deposition on fish gills (<3.5 [micro sign]mol g(-1) dw) and associated stress responses stayed low during the sea salt episode in the river draining the limed catchment. Thus, for acid river systems in coastal areas, catchment liming should be considered as a useful countermeasure for Al toxicity. 相似文献
6.
Polycyclic aromatic hydrocarbons (PAH) include compounds with two or more fused benzene rings, many of which are carcinogens. Industrial sources produce hundreds of PAH, notably in the coke- and aluminium-producing industries. Because PAH are distributed at varying levels between gaseous and particulate phases, exposure assessment has been problematic. Here, we recommend that occupational exposures to naphthalene be considered as a potential surrogate for occupational PAH exposure for three reasons. Naphthalene is usually the most abundant PAH in a given workplace; naphthalene is present almost entirely in the gaseous phase and is, therefore, easily measured; and naphthalene offers several useful biomarkers, including the urinary metabolites 1- and 2-hydroxynaphthalene. These biomarkers can be used to evaluate total-body exposure to PAH, in much the same way that 1-hydroxypyrene has been applied. Using data from published sources, we show that log-transformed airborne levels of naphthalene are highly correlated with those of total PAH (minus naphthalene) in several industries (creosote impregnation: Pearson r= 0.815, coke production: r= 0.917, iron foundry: r= 0.854, aluminium production: r= 0.933). Furthermore, the slopes of the log-log regressions are close to one indicating that naphthalene levels are proportional to those of total PAH in those industries. We also demonstrate that log-transformed urinary levels of the hydroxynaphthalenes are highly correlated with those of 1-hydroxypyrene among coke oven workers and controls (r= 0.857 and 0.876), again with slopes of log-log regressions close to one. These results support the conjecture that naphthalene is a useful metric for occupational PAH exposure. Since naphthalene has also been shown to be a respiratory carcinogen in several animal studies, it is also argued that naphthalene exposures should be monitored per se in industries with high levels of PAH. 相似文献
7.
本文报导了利用氯解和水热技术,对含硫量为2.8%、3.23%和5.5%的 Assam 煤样脱硫研究的结果。在无水情况下完成氯解,继之用水在80℃下水解2小时,结果引起少量有机硫的脱除。改性机理解释了水在氯解过程中的作用。此外,还提出了在水热处理过程中有机硫脱除的机理。 相似文献
8.
9.
利用综合的关于由白铁矿合成的黄铁矿,以及由白铁矿和磁黄铁矿形成的黄铁矿的天然样品的特征,就能识别薄片中由白铁矿转变和由磁黄铁矿氧化淋滤而形成的黄铁矿。由白铁矿转变而形成的黄铁矿的特征有:其孔隙空间约为实际矿物的2%、孔隙内无副产物充填、光学各向异性(暗绿至暗红色)和呈相对于白铁矿母晶具两个取向的他形子体黄铁矿晶畴。由磁黄铁矿氧化溶解(与淋滤作用相反)形成的黄铁矿或白铁矿的特征有:孔隙空间达实际矿物的32%、黄铁矿与磁黄铁矿母晶之间有缝隙、孔隙和缝隙中充填着副产物(菱铁矿、磁铁矿和水硅铁石或其它含铁相)、光学各向同性(对黄铁矿而言)、晶面发育和相对于磁黄铁矿母晶为随机取向。由磁黄铁矿中的铁氧化淋滤(与完全溶解相反)形成的白铁矿也具有大量孔隙,但相对于磁黄铁矿母体呈优选取向。由白铁矿形成的黄铁矿可用作表征白铁矿母晶沉积期间的沉积条件为pH<5和t<~240℃的指示剂。紧随磁黄铁矿溶解后沉淀出的白铁矿,也可以指示矿物变换期间的沉淀条件。由磁黄铁矿氧化淋滤形成的白铁矿不能用作这些沉淀条件的证据。 相似文献
10.
一、引言 象氡一样,氦是未出露的铀或钍矿床的一种示踪元素,其最大优点是He~4很稳定,并能通过大多数岩石或矿物迅速扩散。此外,由于它溶解度极小,因此对进入地下水中比较小的He~4流量也能检测出来。近年来,精确分析氦同位素的质谱计,已经发展到这样一种程度,即对20克水样中溶解氦的He~3/He~4比值都很容易测量,其精度大约为0.2%(与大气氦相比)。 相似文献