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111.
Energy intake and expenditure on natural foraging trips were estimated for the seed-harvester ants, Pogonomyrmex maricopa and P. rugosus. During seed collection, P. maricopa foraged individually, whereas P. rugosus employed a trunk-trail foraging system. Energy gain per trip and per minute were not significantly different between species. There was also no interspecific difference in energy cost per trip, but energy cost per minute was lower for P. maricopa foragers because they spent on average 7 min longer searching for a load on each trip. Including both unsuccessful and successful foraging trips, average energy gain per trip was more than 100 times the energy cost per trip for both species. Based on this result, we suggest that time cost incurred during individual foraging trips is much more important than energy cost in terms of maximizing net resource intake over time. In addition, because energy costs are so small relative to gains, we propose that energy costs associated with foraging may be safely ignored in future tests of foraging theory with seed-harvesting ant species. 相似文献
112.
Marty?L.?LeonardEmail author Andrew?G.?Horn Jackie?Porter 《Behavioral ecology and sociobiology》2003,54(6):573-577
Much of the theoretical work on the evolution of begging assumes this elaborate display is costly. The evidence for an energetic cost to begging has, however, been equivocal. Metabolic studies on nestling birds suggest that begging requires minimal energy, but some growth studies have shown that excess begging reduces growth rates. One difficulty in interpreting these results is that metabolic and growth studies have each been performed on different species. Here, we test whether high begging frequencies depress growth in nestling tree swallows, Tachycineta bicolor, a species in which the metabolic cost of begging has been measured. When we compared the growth of nestlings stimulated to beg at either high or low frequencies, we found no significant differences in their mass gained, wing growth or portion of ingested energy devoted to begging either during the experimental period or in the 24 h following the end of the experiment. We also found no significant relationship between begging intensity and growth measurements. The results of our study are consistent with previous metabolic studies on this species suggesting that the energetic cost of begging is relatively low. More generally, evidence for a fitness cost of begging via decreased growth is equivocal.Communicated by J. Dickinson 相似文献
113.
Chistopher G. Murphy 《Behavioral ecology and sociobiology》1994,34(4):285-294
In all species of anuran amphibians studied to date, male mating success is positively correlated with male chorus tenure (the number of nights that a male is present in breeding aggregations), yet males spend only a small portion of the total breeding season in choruses. Three hypotheses might explain abbreviated chorus tenure in anuran amphibians: (1) mortality, (2) energy limitations, and (3) movement among choruses. I tested these hypotheses in a study of the barking treefrog (Hyla gratiosa), a species with very abbreviated chorus tenure. Mortality accounted for the short tenures of some males: an estimated 20% of males died while calling in the chorus. Energy limitations were an important determinant of chorus tenure. Males lost weight over successive nights in the chorus, and males with longer chorus tenures were in better condition on their first night in the chorus, lost condition more slowly, and were in poorer condition on their last night in the chorus than were males with shorter chorus tenures. Males that I fed crickets as they left the chorus returned sooner and for more nights than did control (unfed) males. Movement between ponds did not explain abbreviated chorus tenure: less than 16% of the males called at more than one pond, and these males increased their chorus tenures by a median of only 2.5 nights by calling in another chorus. Thus, abbreviated chorus tenure in H. gratiosa appears to be primarily the result of energy limitations, with mortality playing a secondary role. 相似文献
114.
煤矿井下气候参数和劳动强度对矿工生理参数影响的研究 总被引:2,自引:1,他引:1
对机械化采煤工作面的采煤机司机和支柱工的劳动心率和能量代谢进行了现场实测。就气候参数和劳动强度对作业人员的生理参数影响进行了模拟实验,取得一些实验研究成果。对改善劳动条件和作业环境,提高生产效率,保护井下矿工的身心健康与安全,提供了科学依据。 相似文献
115.
116.
略谈清洁生产战略在医院废物处理中的指导意义 总被引:1,自引:0,他引:1
清洁生产战略作为环境管理的一项手段 ,是实现可持续发展战略的一项重要举措。医院废物作为一种危险废物 ,在其处理处置过程中 ,也应引入清洁生产思想 ,这对于有效利用资源和能源 ,减轻环境压力 ,都具有重要意义。 相似文献
117.
118.
江苏省节能减排战略研究 总被引:2,自引:1,他引:1
江苏省近年经济稳步增长,人民生活水平不断提高,但经济增长的代价是随之增长的能源消耗,导致对资源需求持续增加,对环境的不利影响日益突出,给节能减排工作造成了沉重的压力。在此对江苏省2000年~2006年社会经济发展与节能减排的耦合关系进行了全面分析.重点分析了江苏省经济总量和产业结构与能源消耗和“三废”排放的关联;总结了江苏省的能耗特点和节能减排工作中存在的问题;并根据江苏省千家企业和百家企业的分布以及不同行业“三废”排放量等指标,明确了节能减排工作的区域与行业重点,提出了江苏省的节能减排战略。 相似文献
119.
浅谈提高环境影响评价中工程分析质量 总被引:2,自引:0,他引:2
提出如何在社会区域类环境影响评价中提高工程分析质量的措施,以齐齐哈尔市第一医院为例,在工艺流程或产污环节分析中,应重点突出与污染物排放有关的工序和污染物的产生量;现有工程的污染物计算应结合监测和生产状况综合分析;以"清洁生产审计"的观点进行"清洁生产分析";对提出的污染物治理措施应具有可操作性。 相似文献
120.
经过多次对煤炭气化高温蒸汽锅炉、型煤锅炉、常压反烧锅炉和蒸汽锅炉等洗浴用小锅炉的测试、分析与评价,确认煤炭气化高温蒸汽锅炉的节能环保指标都比其他锅炉具有显著的优越性。它可以在常压下产生150℃的高温蒸汽,燃烧散煤时其排放的SO2和烟尘都达到国家一级排放标准,锅炉平均热效率可达78.05%,比同吨位的常压热水锅炉和蒸汽锅炉节能30%,比型煤锅炉节能约50%,比燃油锅炉、燃气锅炉、电锅炉节能约60%以上。 相似文献