全文获取类型
收费全文 | 228篇 |
免费 | 13篇 |
国内免费 | 53篇 |
专业分类
安全科学 | 20篇 |
废物处理 | 22篇 |
环保管理 | 22篇 |
综合类 | 83篇 |
基础理论 | 63篇 |
污染及防治 | 71篇 |
评价与监测 | 4篇 |
社会与环境 | 5篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 2篇 |
2022年 | 9篇 |
2021年 | 5篇 |
2020年 | 10篇 |
2019年 | 7篇 |
2018年 | 7篇 |
2017年 | 11篇 |
2016年 | 11篇 |
2015年 | 15篇 |
2014年 | 13篇 |
2013年 | 19篇 |
2012年 | 16篇 |
2011年 | 17篇 |
2010年 | 11篇 |
2009年 | 11篇 |
2008年 | 10篇 |
2007年 | 9篇 |
2006年 | 19篇 |
2005年 | 14篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 12篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 8篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1979年 | 2篇 |
排序方式: 共有294条查询结果,搜索用时 62 毫秒
191.
The purpose of this study was to develop a profile of employees in Fortune 500 companies who are willing to relocate. The profile was developed on a demographically diverse random sample of 827 employees from 20 Fortune 500 corporations, all of whom had moved at least once for their current employer. Employees who were most willing to relocate were younger, their incomes were lower, their career ambitions higher, and their spouses more willing than those who were less willing to relocate. These employees could be found in sales/marketing and production functions. Their attitudes toward moving were also favorable. The single most important predictor of willingness to relocate was spouse willingness to relocate. This result suggests strongly that in the 1990s, corporations are going to have to address the concerns of spouses, if married employees are going to remain mobile. The study also cautions corporations about the shortsightedness of thinking of spouse and dual career issues as ’women's issues‘ and assuming that females and minorities are unwilling to relocate. 相似文献
192.
Russell C. Van Horn Jason C. Buchan Jeanne Altmann Susan C. Alberts 《Behavioral ecology and sociobiology》2007,61(12):1823-1837
Group living provides benefits to individuals while imposing costs on them. In species that live in permanent social groups,
group division provides the only opportunity for nondispersing individuals to change their group membership and improve their
benefit to cost ratio. We examined group choice by 81 adult female savannah baboons (Papio cynocephalus) during four fission events. We measured how each female’s group choice was affected by several factors: the presence of
her maternal kin, paternal kin, age peers, and close social partners, her average kinship to groupmates, and her potential
for improved dominance rank. Maternal kin, paternal kin, and close social partners influenced group choice by some females,
but the relative importance of these factors varied across fissions. Age peers other than paternal kin had no effect on group
choice, and average kinship to all groupmates had the same effect on group choice as did maternal kin alone. Most females
were subordinate to fewer females after fissions than before, but status improvement did not drive female group choice; females
often preferred to remain with social superiors who were their close maternal kin, rather than improving their own social
ranks. We suggest that during permanent group fissions, female baboons prefer to remain with close maternal kin if those are
abundant enough to influence their fitness; if they have too few close maternal kin then females prefer to remain with close
paternal kin, and social bonds with nonkin might also become influential.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
193.
固体废物进出口是影响我国生态文明建设及区域可持续发展的重要因素,也是最近环境管理关注的焦点。为了认识我国固体废物的进出口形势和全球固体废物贸易的格局,本文以进口量最大的固体废物——废纸为例,系统总结梳理了近年来我国废纸进出口情况的演化,绘制了2016年国际废纸贸易的流向地图,从2015年以来的废物管理政策调整出发探讨未来废纸产业的发展和转变。研究发现:(1)作为主要的造纸原材料,我国废纸进口量从1996年的137万t增加到2016年的2850万t,增长了近20倍。(2)当前全球废纸贸易突出表现为发达国家出口、发展中国家进口的格局,我国作为最大的废纸进口国,进口约占全球总量55%的废纸,美国则为最大的废纸出口国,出口约占全球总量36%的废纸。(3)应对洋垃圾入境的挑战,未来我国应在进口管控、再生资源产业发展等多个方面继续加强政策的引导和调控作用,激励国内的再生资源市场,促使废纸利用企业调整产业布局,加快产业转型。 相似文献
194.
Yao Chen Jinhui Li Huabo Duan Zhishi Wang 《Frontiers of Environmental Science & Engineering in China》2011,5(2):167-174
Mechanical waste-processing methods, which combine crushing and separation processes for the recovery of valuable materials,
have been widely applied in waste printed wiring board (PWB) treatment. However, both the high impact toughness and the tensile
and flexural strengths of whole PWB with a laminated structure result in great energy consumption and severe abrasion of the
cutters during multi-level crushing. In addition, the high temperatures occurring in continual crushing probably cause the
decomposition of the polymer matrix. A thermal-crack method using residual steam as the heating medium has been developed
to pre-treat waste PWBs. This treatment reduces the mechanical strength in order to improve the recovery rate of valuable
materials in subsequent mechanical recycling. The changes of the PWBs’ macro-mechanical properties were studied to evaluate
thermal expansion impacts associated with changes in temperature, and the dynamic dislocation micro-structures were observed
to identify the fracture mechanism. The results showed that thermal cracking with steam at the temperature of 500 K can effectively
attenuate the mechanical properties of waste PWBs, by reducing the impact, tensile and flexural strengths respectively, by
59.2%, 49.3% and 51.4%, compared to untreated PWB. Thermal expansion can also facilitate the separation of copper from glass
fiber by reducing peel resistance by 95.4% at 500 K. It was revealed that the flexural fracture was a transverse cracking
caused by concentrated stress when the heating temperature was less than 500 K, and shifted to a vertical cracking after exceeding
500 K. 相似文献
195.
196.
为了减少矿工不安全行为的发生,以陕西煤业化工集团神南矿业公司为研究样本,基于扎根理论对矿工不安全行为成本和矿工不安全行为收益进行识别,通过实地访谈收集资料,将访谈内容进行编码处理,建立矿工不安全行为成本和收益识别的概念模型,并以此构建矿工不安全行为成本和收益识别的动态模型图;最后,通过模型理论饱和度检验,证明模型中展现的脉络关系是饱和的。研究结果表明:矿工自身的安全意识、人口统计特征因素及情景因素,对矿工不安全行为成本和收益有着重要影响;风险成本、预备成本和实施成本构成矿工不安全行为成本,精神收益和物质收益构成矿工不安全行为收益。 相似文献
197.
Nga Nguyen Russell C. Van Horn Susan C. Alberts Jeanne Altmann 《Behavioral ecology and sociobiology》2009,63(9):1331-1344
Close associations between adult males and lactating females and their dependent infants are not commonly described in non-monogamous
mammals. However, such associations [sometimes called “friendships” (Smuts 1985)] are regularly observed in several primate species in which females mate with multiple males during the fertile period.
The absence of mating exclusivity among “friends” suggests that males should invest little in infant care, raising questions
about the adaptive significance of friendship bonds. Using data from genetic paternity analyses, patterns of behavior, and
long-term demographic and reproductive records, we evaluated the extent to which friendships in four multi-male, multi-female
yellow baboon (Papio cynocephalus) groups in Amboseli, Kenya represent joint parental care of offspring or male mating effort. We found evidence that mothers
and infants benefited directly from friendships; friendships provided mother–infant dyads protection from harassment from
other adult and immature females. In addition, nearly half of all male friends were the genetic fathers of offspring and had
been observed mating with mothers during the days of most likely conception for those offspring. In contrast, nearly all friends
who were not fathers were also not observed to consort with the mother during the days of most likely conception, suggesting
that friendships between mothers and non-fathers did not result from paternity confusion. Finally, we found no evidence that
prior friendship increased a male’s chances of mating with a female in future reproductive cycles. Our results suggest that,
for many male–female pairs at Amboseli, friendships represented a form of biparental care of offspring. Males in the remaining
friendship dyads may be trading protection of infants in exchange for some resources or services not yet identified. Our study
is the first to find evidence that female primates gain social benefits from their early associations with adult males.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
198.
199.
Mathieu Muller Sihem Bouguelia Romy-Alice Goy Alison Yoris Jeanne Berlin Perrine Meche Vincent Rocher Sharon Mertens Yves Dudal 《Environmental science and pollution research international》2014,21(23):13642-13645
BOD5 dates back to 1912 when the Royal Commission decided to use the mean residence time of water in the rivers of England, 5 days, as a standard to measure the biochemical oxygen demand. Initially designed to protect the quality of river waters from extensive sewage discharge, the use of BOD5 has been quickly extended to waste water treatment plants (WWTPs) to monitor their efficiency on a daily basis. The measurement has been automatized but remains a tedious, time- and resource-consuming analysis. We have cross-validated a surrogate BOD5 method on two sites in France and in the USA with a total of 109 samples. This method uses a fluorescent redox indicator on a 96-well microplate to measure microbial catabolic activity for a large number of samples simultaneously. Three statistical tests were used to compare surrogate and reference methods and showed robust equivalence. 相似文献
200.