全文获取类型
收费全文 | 8473篇 |
免费 | 9篇 |
国内免费 | 318篇 |
专业分类
安全科学 | 208篇 |
废物处理 | 401篇 |
环保管理 | 870篇 |
综合类 | 928篇 |
基础理论 | 526篇 |
环境理论 | 1篇 |
污染及防治 | 3995篇 |
评价与监测 | 1176篇 |
社会与环境 | 614篇 |
灾害及防治 | 81篇 |
出版年
2024年 | 2篇 |
2023年 | 11篇 |
2022年 | 7篇 |
2021年 | 3篇 |
2020年 | 11篇 |
2019年 | 13篇 |
2018年 | 11篇 |
2017年 | 14篇 |
2016年 | 7篇 |
2015年 | 29篇 |
2014年 | 24篇 |
2013年 | 24篇 |
2012年 | 817篇 |
2011年 | 1103篇 |
2010年 | 127篇 |
2009年 | 262篇 |
2008年 | 1036篇 |
2007年 | 954篇 |
2006年 | 778篇 |
2005年 | 639篇 |
2004年 | 599篇 |
2003年 | 543篇 |
2002年 | 466篇 |
2001年 | 362篇 |
2000年 | 229篇 |
1999年 | 92篇 |
1998年 | 23篇 |
1997年 | 29篇 |
1996年 | 41篇 |
1995年 | 37篇 |
1994年 | 31篇 |
1993年 | 34篇 |
1992年 | 45篇 |
1991年 | 31篇 |
1990年 | 50篇 |
1989年 | 34篇 |
1988年 | 34篇 |
1987年 | 55篇 |
1986年 | 14篇 |
1985年 | 32篇 |
1984年 | 24篇 |
1983年 | 23篇 |
1982年 | 18篇 |
1981年 | 25篇 |
1980年 | 25篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1974年 | 4篇 |
排序方式: 共有8800条查询结果,搜索用时 31 毫秒
91.
In 1964, Walter Rothenbuhler proposed a two-gene model to explain phenotypic variance in the remarkable behavior in which honey bee workers remove dead brood from their colonies. Rothenbuhler's model proposed that one locus controls the uncapping of brood cells containing dead pupae, while a second controls the removal of the cell contents. We show here, through molecular techniques and quantitative trait loci (QTL) linkage mapping, that the genetic basis of hygienic behavior is more complex, and that many genes are likely to contribute to the behavior. In our cross, we detected seven suggestive QTLs associated with hygienic behavior. Each detected QTL controlled only 9-15% of the observed phenotypic variance in the character. 相似文献
92.
93.
Jenny M. McCarthy Thomas Gumbricht Terence McCarthy Philip Frost Konrad Wessels Frank Seidel 《Ambio-人类环境杂志》2003,32(7):453-457
欧科范果三角洲地区泛滥范围年年在变化.这种变化与安哥拉高地集水区的区域性降水及当地降雨量有关.我们采用了1972~2000年的3000多幅卫星图像来描绘湿地的格局,其中从1985~2000年的图像几乎是NOAAAVHRR每日连续传送的,1972年以来的其它图像是从Landsat传感器上传下来的,其连续性次之.对AVHRR图像每10天为一期,用无监督分类方法分成陆地和水体.对LandsatTM和ERS2-ATSR数据进行分析的结果,与测算的淹没区域89%相吻合.结果显示欧科范果湿地近期30年期间的变化约在2450~11400km2之间. 相似文献
94.
本文介绍了一种确定岩石和矿物样品中铀含量的放射化学中子活化技术。这种方法是基于碱熔样品,用硝酸钠溶液对碘的选择氧化和用蒸馏法分出裂变产物 I~(133)。这种方法是迅速、灵敏和可靠的。 相似文献
95.
电化学处理目前用电化学法处理工业废水的越来越多。在无隔膜电解槽中阳极氧化有机杂质很有效。有机污染物可通过原子氧、氯以及电化学法进行氧化。电解槽的阳极一般用石墨、钛、氧化钌钛涂层,而阴极一般用不锈钢和钛涂层,此时多数情况下不生成沉淀。在以石墨或涂钌钛氧化物的电极为阳极无隔膜电解槽中进行了净 相似文献
96.
A survey is given on fluid-dynamic effects caused by the structure and properties of biological surfaces. It is demonstrated
that the results of investigations aiming at technological applications can also provide insights into biophysical phenomena.
Techniques are described both for reducing wall shear stresses and for controlling boundary-layer separation. (a) Wall shear
stress reduction was investigated experimentally for various riblet surfaces including a shark skin replica. The latter consists
of 800 plastic model scales with compliant anchoring. Hairy surfaces are also considered, and surfaces in which the no-slip
condition is modified. Self-cleaning surfaces such as that of lotus leaves represent an interesting option to avoid fluid-dynamic
deterioration by the agglomeration of dirt. An example of technological implementation is discussed for riblets in long-range
commercial aircraft. (b) Separation control is also an important issue in biology. After a few brief comments on vortex generators,
the mechanism of separation control by bird feathers is described in detail. Self-activated movable flaps (=artificial bird
feathers) represent a high-lift system enhancing the maximum lift of airfoils by about 20%. This is achieved without perceivable
deleterious effects under cruise conditions. Finally, flight experiments on an aircraft with laminar wing and movable flaps
are presented. 相似文献
97.
98.
<正> 酚和酚的化合物可以拢乱生物过程,如生长(AMER & ALI 1969,SHARMA& GHOSH 1965)和发育(KORDYLEM-SKA 1980a,1980b).为进行酚对水生生物影响的研究,所以必须寻找可靠而重复性好的分析方法,以测定海水中单个酚类的浓度.已经报导了用高效液相色谱(OGAN& KATZ 1981),气相色谱(COUTTS 等1979,SUPELCO 公司1975)和分光光度法(KOPPE 等1977.OCHINSKI 1960)分析水中酚类,而这些方法由于需要花费时间萃 相似文献
99.
100.
The Henze precipitate, a peculiar blue-green microparticulate obtained by lysis of the blood cells of the ascidian Phallusia mammillata (Protochordata), was investigated with atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray microanalysis. The precipitate was collected from the Henze solution, an unstable red-brown product obtained by treating blood with distilled water, whose degradation yields a characteristic blue-green product. The microparticulates measured 50–100 µm in diameter and appeared irregular in shape. SEM examination showed smooth, roughly round boundaries. The microparticulate surface examined with AFM appeared as an irregular matrix formed by 70–320-nm-wide mammillate composites, including and embedding small (500–800 nm wide) crystal-like multilayered formations. X- ray analysis showed that the elements present in these same precipitates were mainly C, Si, Al and O. The microparticulate composition appeared close to those of natural waxes or lacquers, embedding amorphous silicates and/or other Si–Al components. The unusual occurrence of Si in ascidian blood and its role are discussed. 相似文献