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681.
682.
Olivier Le Curieux-Belfond Louise Vandelac Joseph Caron Gilles-Éric Séralini 《Environmental Science & Policy》2009,12(2):170-189
Many genetically modified plants have been developed, and four of them (soya, maize, cotton, and colza) representing more than 99% of commercial crops, are widely distributed, mainly in the United States and in America [ISAAA, 2006. Report on global status on biotech/GM crops, Brief 35. International Service for the Acquisition of Agri-biotech Applications organization, US]. Yet all over the world policy is still in development in regard to authorization of modified plants and modified and/or cloned animals for food or feed and for their environmental release. The most advanced animal commercial projects concern various fish species, more easy to genetically transform, notably because conception and development take place in water and easy access to numerous eggs. A request for authorization to introduce genetically modified (GM) salmon onto the market has been presented to the Food and Drug Administration (FDA) of the US. In the interim, questions have been raised concerning the impacts of transgenic salmon, modified for productivity, on aquaculture, wildlife, ecosystems and on human health. Herein we review these scientific studies and sanitary, environmental, social and economic arguments. This paper analyses current gaps in the knowledge of the impacts of transgenic fish and proposes legislation orientations necessary for environmental and sanitary protection, should the marketing of animal genetically modified organisms (GMOs) be authorized. 相似文献
683.
刘乐 《安全.健康和环境》2010,10(12):49-50
TPM是全员生产维护的英文缩写,即全体人员,包括企业领导、生产现场工人以及办公室人员参加的生产维修、维护体制。它起源于美国,后来在日本发展成为全员生产维护。TnPM即全员规范化生产维护,是中国式的TPM。是中国设备管理发展的一种新模式,着重于生产现场的设备管理,是以提高设备综合效率为目标(全效率), 相似文献
684.
Soizic Le Fur Emmanuel Fara Hassane Taïsso Mackaye Patrick Vignaud Michel Brunet 《Die Naturwissenschaften》2009,96(5):565-574
Characterizing the paleoenvironmental context of the first hominids is a key issue for understanding their behavioral and
morphological evolution. The present study aims at reconstructing the paleoenvironment of the TM266 vertebrate assemblage
(Toros-Menalla, Northern Chad) that yielded the earliest known hominid Sahelanthropus tchadensis (7 Ma). For the first time, a quantitative analysis is carried out on the fossil mammal assemblage associated with that hominid.
Two complementary approaches were applied: (1) the analysis of the relative abundances of taxa and their habitat preferences;
and (2) the study of the distribution of taxa within three meaningful ecovariables: locomotion, feeding preferences, and body
mass. The resulting taxonomic and paleoecological structures are used to reconstruct the diversity and the relative extent
of the habitats in that part of northern Chad seven million years ago. The paleoenvironment was composed of open areas with
dry and humid grasslands, prevailing over wooded habitats. Water was also widely available as freshwater bodies and certainly
swamps. It appears that the high habitat diversity of the landscape is a common feature among paleoenvironments associated
with early hominids. 相似文献
685.
686.
Rüdiger Riesch Martin Plath Francisco J. García de León Ingo Schlupp 《Die Naturwissenschaften》2010,97(2):133-141
The majority of studies on ecological speciation in animals have investigated the divergence caused by biotic factors like
divergent food sources or predatory regimes. Here, we examined a system where ecological speciation can clearly be ascribed
to abiotic environmental gradients of naturally occurring toxic hydrogen sulfide (H2S). In southern Mexico, two genera of livebearing fishes (Poeciliidae: Poecilia and Gambusia) thrive in various watercourses with different concentrations of H2S. Previous studies have revealed pronounced genetic differentiation between different locally adapted populations in one
species (Poecilia mexicana), pointing towards incipient speciation. In the present study, we examined female reproductive life-history traits in two
species pairs: Gambusia sexradiata (from a nonsulfidic and a sulfidic habitat) and Gambusia eurystoma (sulfide-endemic), as well as P. mexicana (nonsulfidic and sulfidic) and Poecilia sulphuraria (sulfide endemic). We found convergent divergence of life-history traits in response to sulfide; most prominently, extremophile
poeciliids exhibit drastically increased offspring size coupled with reduced fecundity. Furthermore, within each genus, this
trend increased with increasing sulfide concentrations and was most pronounced in the two endemic sulfur-adapted species.
We discuss the adaptive significance of large offspring size in toxic environments and propose that divergent life-history
evolution may promote further ecological divergence through isolation by adaptation. 相似文献
687.
688.
689.
基于苋菜转录组的ARF基因家族鉴定及表达 总被引:1,自引:0,他引:1
ARFs(auxin response factors)是重要的生长素响应因子,在植物的生长发育过程中起着关键的作用.基于'大红'苋菜转录组数据,通过在线分析软件SMART和NCBI-Blastp的注释筛选苋菜ARF基因家族成员(AtrARF);利用生物信息学分析软件,对AtrARFs蛋白的理化性质、二级结构、亚细胞定... 相似文献
690.
三峡水库中下游水体氮磷时空变化与机制分析 总被引:1,自引:0,他引:1
2010年每月定期测定了位于三峡水库中下游的云阳、巫山、秭归和三斗坪段的TN、NH4 N、NO3 N和TP浓度。结果表明:4个段面水质中的TN、NH4 N、NO3 N和TP浓度空间差异不显著,但季节变化显著,TN和TP的季节变化呈单峰格局,分别在5月和7月达到最大值;NH4 N的季节变化则呈双峰格局,主要的峰值出现在7、8月,次要的峰值出现在3、4月。4个地点低水位期(3~8月)的TN、NH4 N、NO3 N和TP浓度都高于高水位期(9月~次年2月)。主要因为在低水位期,长江上游和三峡库区的降雨量大,入库流量显著增加,污染物主要来自长江上游入库的非点源污染和水库两岸农田施用农药化肥造成的面源污染。三峡水库三期蓄水后,水库水质与前两期蓄水后的水质变化不大,水质仍然保持良好,高水位期为Ⅲ类水质,低水位期为Ⅳ类水质 相似文献