全文获取类型
收费全文 | 16207篇 |
免费 | 113篇 |
国内免费 | 70篇 |
专业分类
安全科学 | 338篇 |
废物处理 | 642篇 |
环保管理 | 1941篇 |
综合类 | 3748篇 |
基础理论 | 3668篇 |
环境理论 | 6篇 |
污染及防治 | 3967篇 |
评价与监测 | 1018篇 |
社会与环境 | 1016篇 |
灾害及防治 | 46篇 |
出版年
2022年 | 113篇 |
2021年 | 132篇 |
2019年 | 127篇 |
2018年 | 201篇 |
2017年 | 194篇 |
2016年 | 316篇 |
2015年 | 250篇 |
2014年 | 365篇 |
2013年 | 1098篇 |
2012年 | 411篇 |
2011年 | 619篇 |
2010年 | 476篇 |
2009年 | 559篇 |
2008年 | 641篇 |
2007年 | 678篇 |
2006年 | 606篇 |
2005年 | 510篇 |
2004年 | 531篇 |
2003年 | 519篇 |
2002年 | 489篇 |
2001年 | 622篇 |
2000年 | 397篇 |
1999年 | 295篇 |
1998年 | 186篇 |
1997年 | 205篇 |
1996年 | 224篇 |
1995年 | 235篇 |
1994年 | 233篇 |
1993年 | 219篇 |
1992年 | 198篇 |
1991年 | 207篇 |
1990年 | 198篇 |
1989年 | 169篇 |
1988年 | 168篇 |
1987年 | 154篇 |
1986年 | 153篇 |
1985年 | 148篇 |
1984年 | 169篇 |
1983年 | 167篇 |
1982年 | 172篇 |
1981年 | 145篇 |
1980年 | 132篇 |
1979年 | 123篇 |
1978年 | 134篇 |
1977年 | 115篇 |
1976年 | 103篇 |
1975年 | 107篇 |
1974年 | 118篇 |
1971年 | 98篇 |
1967年 | 101篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
At 10 weeks' gestation, chorionic villus biopsy was obtained from a woman at risk for Sanfilippo type C disease. Acetyl-CoA: α-glucosaminide N-acetyltransferase activity was markedly deficient. The pregnancy was terminated at 12 weeks' gestation and follow-up study on fetal fibroblasts confirmed the diagnosis. 相似文献
993.
Canadian and US marine conservation law, and other related law, was analyzed to determine if it reflected ecological criteria needed to implement connectivity among marine protected areas of the northeast Pacific in the proposed trilateral Baja to Bering Sea (B2B) initiative. The analysis included both nations’ federal laws and those of California, Oregon, Washington, Alaska, and British Columbia. While legal provisions exist already to implement marine protected areas for varying reasons, there is little capacity in most laws to create connectivity among them for conservation purposes. Only California's legislation contained explicit provisions for all the criteria. Other federal, state, and provincial laws, while containing provisions for species at risk and vulnerable habitats, generally lacked explicit provisions for the vital criteria, size of area, migratory patterns, and recruitment patterns. Implementation, future management, and protection of the proposed B2B marine network would be facilitated by amendment of both Canadian and US laws. Some of the ecological criteria are already implied implicitly or vaguely, but they need to be made explicit in the amended law. The legislative model of California could serve as a template for amending the laws of other jurisdictions in the B2B venture. 相似文献
994.
Guangxue Wu Zhenhu Hu Mark G. Healy Xinmin Zhan 《Frontiers of Environmental Science & Engineering in China》2009,3(3):300-306
Since the solubilization of meat and bone meal (MBM) is a prerequisite in many MBM disposal approaches, enhancement of the
solubilization by means of thermochemical pretreatment was investigated in this study at two temperatures (55°C and 131°C)
and six sodium hydroxide (NaOH) concentrations (0, 1.25, 2.5, 5, 10 and 20 g/L). The MBM volatile solid (VS) reduction ratio
was up to 66% and 70% at 55°C and 131°C, respectively. At the same temperature, the VS reduction ratio increased with the
increase in the dosage of NaOH. The study on the methane (CH4) production potential of pretreated MBM shows that the addition of NaOH at 55°C did not cause the inhibition of the succeeding
CH4 production process. However, CH4 production was inhibited by the addition of NaOH at 131°C. The CH4 production potential was in the range of 389 to 503 mL CH4/g VS MBM and 464 to 555 mL CH4/g VS MBM at 55°C and 131°C, respectively. 相似文献
995.
996.
We thank B. Zentgraf for his basic and constructive ideas and his field support, R. Andi Abdoerrachman for logistic and technical support and E. Shimokawa, Kagoshima University, for providing a charcoal sample from Kutai National Park. We thank P. Becker-Heidmann, Isotope Dating Laboratory, University of Hamburg, for his immediate 14C-dating by Liquid Scintillation Counting, and Chr. Goedicke, Rathgen Research Laboratory, Staatliche Museen Preussischer Kulturbesitz Berlin, for immediate TL dating. M. A. Gill, C.S.I.R.O. Canberra, has critically reviewed this paper. This research was sponsored by the Volkswagen Foundation. 相似文献
997.
998.
999.
G. Siegert 《Die Naturwissenschaften》1984,71(7):370-371
1000.
Incineration experiments with MSW, which had been impregnated with heavy metals, were presented to obtain information on the volatilization behavior of the elements cadmium (Cd), lead (Pb), and zinc (Zn) under different conditions. Experiments were carried out in a bubbling fluid bed system connected to a customized inductively coupled plasma optical emission spectroscopy(ICP-OES) for analyzing metals in the flue gas. The results indicated that the combustion temperature, the gas atmosphere, and the chlorine content in the flue gas could affect the volatilization behavior of heavy metals. In the fluidized bed combustion, a large surface area was provided by the bed sand particles, and they may act as absorbents for the gaseous ash-forming compound. Comparer with the metals Cd and Pb, the vaporization of Zn was low. The formation of stable compounds such as ZnO.Al2O3 could greatly decrease the metals volatilization. The presence of chlorine would enhance the volatilization of heavy metals by increasing the formation of metal chlorides. However, when the oxygen content was high, the chlorinating reaction was kinetically hindered, which heavy metals release would be delayed. 相似文献