全文获取类型
收费全文 | 686篇 |
免费 | 79篇 |
专业分类
林业 | 41篇 |
农学 | 30篇 |
基础科学 | 2篇 |
119篇 | |
综合类 | 29篇 |
农作物 | 50篇 |
水产渔业 | 128篇 |
畜牧兽医 | 281篇 |
园艺 | 10篇 |
植物保护 | 75篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 20篇 |
2021年 | 35篇 |
2020年 | 33篇 |
2019年 | 43篇 |
2018年 | 43篇 |
2017年 | 40篇 |
2016年 | 26篇 |
2015年 | 27篇 |
2014年 | 33篇 |
2013年 | 57篇 |
2012年 | 49篇 |
2011年 | 58篇 |
2010年 | 20篇 |
2009年 | 22篇 |
2008年 | 36篇 |
2007年 | 25篇 |
2006年 | 34篇 |
2005年 | 19篇 |
2004年 | 13篇 |
2003年 | 15篇 |
2002年 | 13篇 |
2001年 | 19篇 |
2000年 | 11篇 |
1999年 | 7篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1971年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有765条查询结果,搜索用时 0 毫秒
761.
Coagulation and flocculation are basic chemical engineering operations employed to remove suspended solids from water. The
growing concern for environmental and ecological issues warrants the use of the biodegradable flocculants in wastewater and
industrial effluent treatment. In this work, unconventional coagulant, namely lactic acid, calcium lactate, sodium lactate,
and citric acid were studied in comparison with AlCl3, a usual coagulant widely employed to remove water turbidity. It was observed that lactic acid and calcium lactate were able
to reduce the water turbidity similarly to AlCl3. This fact can be very interesting because lactic acid salts can be produced by biotechnological process, and contrarily
to aluminium salts, they are biodegradable, reducing the risk for human and animal’s health. 相似文献
762.
Anuada Anecito M. Cruz Pompe C. Sta. De Guzman Lucille Elna P. Sanchez Pearl B. 《Journal of Crop Science and Biotechnology》2022,25(2):133-147
Journal of Crop Science and Biotechnology - Determining the factors affecting the yield of corn varieties due to genotype by environment (G?×?E) interaction can be helpful in the... 相似文献
763.
Cruz M Turok N Vielva P Martínez-González E Hobson M 《Science (New York, N.Y.)》2007,318(5856):1612-1614
The Cosmic Microwave Background provides our most ancient image of the universe and our best tool for studying its early evolution. Theories of high-energy physics predict the formation of various types of topological defects in the very early universe, including cosmic texture, which would generate hot and cold spots in the Cosmic Microwave Background. We show through a Bayesian statistical analysis that the most prominent 5 degrees -radius cold spot observed in all-sky images, which is otherwise hard to explain, is compatible with having being caused by a texture. From this model, we constrain the fundamental symmetry-breaking energy scale to be (0) approximately 8.7 x 10(15) gigaelectron volts. If confirmed, this detection of a cosmic defect will probe physics at energies exceeding any conceivable terrestrial experiment. 相似文献
764.
Russell JD Cruz M White JL Bailey GW Payne WR Pope JD Teasley JI 《Science (New York, N.Y.)》1968,160(3834):1340-1342
Chemical hydrolysis of the s-triazines after interaction with less than 2-micron (equivalent spherical diameter) montmorillonite clay occurs as a result of protonation at the colloidal surface; protonation occurs even when the exchange sites are occupied by metallic cations. The adsorbed hydrolytic degradation product is not the hydroxy analog, but it is predominantly the keto form of the protonated hydroxy species. This cationic form is held tightly by the clay which may restrict vertical movement and entrance into groundwater. Protonation of the hydroxy analog occurs on the heterocyclic ring nitrogen. 相似文献
765.