全文获取类型
收费全文 | 23727篇 |
免费 | 333篇 |
国内免费 | 1227篇 |
专业分类
安全科学 | 673篇 |
废物处理 | 1093篇 |
环保管理 | 2996篇 |
综合类 | 5089篇 |
基础理论 | 6345篇 |
环境理论 | 10篇 |
污染及防治 | 6474篇 |
评价与监测 | 1382篇 |
社会与环境 | 958篇 |
灾害及防治 | 267篇 |
出版年
2022年 | 275篇 |
2021年 | 258篇 |
2020年 | 188篇 |
2019年 | 212篇 |
2018年 | 352篇 |
2017年 | 396篇 |
2016年 | 550篇 |
2015年 | 469篇 |
2014年 | 766篇 |
2013年 | 1921篇 |
2012年 | 834篇 |
2011年 | 1111篇 |
2010年 | 894篇 |
2009年 | 875篇 |
2008年 | 1108篇 |
2007年 | 1056篇 |
2006年 | 941篇 |
2005年 | 783篇 |
2004年 | 719篇 |
2003年 | 723篇 |
2002年 | 690篇 |
2001年 | 844篇 |
2000年 | 640篇 |
1999年 | 390篇 |
1998年 | 340篇 |
1997年 | 341篇 |
1996年 | 340篇 |
1995年 | 386篇 |
1994年 | 330篇 |
1993年 | 316篇 |
1992年 | 307篇 |
1991年 | 294篇 |
1990年 | 307篇 |
1989年 | 292篇 |
1988年 | 258篇 |
1987年 | 251篇 |
1986年 | 227篇 |
1985年 | 202篇 |
1984年 | 259篇 |
1983年 | 213篇 |
1982年 | 272篇 |
1981年 | 222篇 |
1980年 | 184篇 |
1979年 | 201篇 |
1978年 | 184篇 |
1977年 | 153篇 |
1974年 | 159篇 |
1973年 | 162篇 |
1972年 | 148篇 |
1971年 | 146篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
95.
96.
Giant reed for selenium phytoremediation under changing climate 总被引:1,自引:0,他引:1
Hassan R. El-Ramady Neama Abdalla Tarek Alshaal Ahmed S. Elhenawy Mohamed S. Shams Salah E.-D. A. Faizy El-Sayed B. Belal Said A. Shehata Mohamed I. Ragab Megahed M. Amer Miklós Fári Attila Sztrik József Prokisch Dirk Selmar Ewald Schnug Elizabeth A. H. Pilon-Smits Samia M. El-Marsafawy Éva Domokos-Szabolcsy 《Environmental Chemistry Letters》2015,13(4):359-380
97.
98.
This research aimed to investigate the interspecific and intraspecific identification of Dendrobium by using the multi-locus method so as to provide a molecular basis for Dendrobium identification through the combination of chloroplast psbA-trnH intergenic region sequences and ribosome 5S rRNA gene spacer sequences. PCR direct sequencing was applied to detect the chloroplast psbA-trnH intergenic region sequences as well as the ribosome 5S rRNA gene spacer sequences of 12 Dendrobium species, while the psbA-trnH intergenic region sequences of Dendrobium denneanum dq-2 variety and dq- 5line were cloned and sequenced for single nucleotide polymorphism (SNP) analyzing. The sequences were analyzed by the software Sequencher4.14, Bioedit7.0, MEGA5.2 and Dansp5.0; the interspecific and intraspecific Kimara-2-Parameter(K2P) distances were also calculated. The phylogenetic tree (using Neighbor joining method) was constructed with Bulbophyllum odoratissimum and Bletilla striata as outgroup. The results showed an average length of chloroplast psbA-trnH gene sequences in Dendrobium as 742.3 bp, with 72 variable sites, including 33 information sites; the average length of the ribosome 5S rRNA gene spacer sequences in Dendrobium was 336.4 bp, with 213 variable sites including 139 information sites. Using psbAtrnH intergenic region sequences in combination with ribosome 5S rRNA gene spacer sequences can not only identify D. denneanum, D. hancockil, D. thysiflorum, D. devonianum, D. moniliforme, D. chrysotoxum, D. officinale, D. heterocarpum and D. nobile, but also differentiate D. officinale from different geographical populations, and distinguish the dq-2 variety and dq 5line with SNP in the multi locus of D. denneanum. 相似文献
99.
Social media and disasters: a functional framework for social media use in disaster planning,response, and research 总被引:1,自引:0,他引:1
J. Brian Houston Joshua Hawthorne Mildred F. Perreault Eun Hae Park Marlo Goldstein Hode Michael R. Halliwell Sarah E. Turner McGowen Rachel Davis Shivani Vaid Jonathan A. McElderry Stanford A. Griffith 《Disasters》2015,39(1):1-22
A comprehensive review of online, official, and scientific literature was carried out in 2012–13 to develop a framework of disaster social media. This framework can be used to facilitate the creation of disaster social media tools, the formulation of disaster social media implementation processes, and the scientific study of disaster social media effects. Disaster social media users in the framework include communities, government, individuals, organisations, and media outlets. Fifteen distinct disaster social media uses were identified, ranging from preparing and receiving disaster preparedness information and warnings and signalling and detecting disasters prior to an event to (re)connecting community members following a disaster. The framework illustrates that a variety of entities may utilise and produce disaster social media content. Consequently, disaster social media use can be conceptualised as occurring at a number of levels, even within the same disaster. Suggestions are provided on how the proposed framework can inform future disaster social media development and research. 相似文献
100.