全文获取类型
收费全文 | 164篇 |
免费 | 20篇 |
专业分类
林业 | 29篇 |
农学 | 2篇 |
基础科学 | 1篇 |
27篇 | |
综合类 | 22篇 |
农作物 | 11篇 |
水产渔业 | 9篇 |
畜牧兽医 | 63篇 |
园艺 | 6篇 |
植物保护 | 14篇 |
出版年
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 13篇 |
2016年 | 12篇 |
2015年 | 23篇 |
2014年 | 9篇 |
2013年 | 8篇 |
2012年 | 5篇 |
2011年 | 6篇 |
2010年 | 6篇 |
2009年 | 4篇 |
2008年 | 8篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 6篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1988年 | 4篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
排序方式: 共有184条查询结果,搜索用时 0 毫秒
181.
C. Sakly M. Rekik I. Ben Salem N. Lassoued A. Gonzalez‐Bulnes H. Ben Salem 《Journal of animal physiology and animal nutrition》2014,98(1):43-49
Reproductive outputs in fat‐tailed Barbarine sheep in central Tunisia are often low because of feed shortage and the low nutritive value of diets. Supplementation with conventional concentrates is economically unsuitable in central Tunisia, so more cost‐effective and sustainable alternative feeding strategies need to be developed. We tested effects of short‐term nutritional treatments including cactus cladodes during the induction of ‘male effect’ on fertility and prolificacy parameters (follicular growth, ovulatory response and early embryo losses). One hundred and twenty ewes were distributed in 4 equal groups balanced for live weight grazed natural pastures and were supplemented for 21 days, starting day 10 after introduction of rams, with cactus cladodes (CA), cactus cladodes and soybean meal (CAS), concentrate (CC) or only soybean meal (S). Nutritional treatment did not affect live weight in this experiment. Ewes receiving cactus had higher number of large pre‐ovulatory follicles (≥6 mm; 1.08 ± 0.05), between days 14 and 19 after introduction of rams, than females in the CC and S ewes (0.64 ± 0.06; p < 0.05). However, there were no differences in the onset of oestrous behaviour in response to ‘male effect’ or in the number of corpora lutea. Average ovulation rates were 1.42 ± 0.16 for CC, 1.47 ± 0.13 for CAS, 1.31 ± 0.15 for CA and 1.31 ± 0.13 for S groups respectively. Finally, reproductive wastages at day 35 after mating were not different between groups being 0.33 ± 0.19 for CC, 0.60 ± 0.17 for CAS, 0.43 ± 0.16 for CA and 0.31 ± 0.15 for S groups respectively. It is concluded that Barbarine ewes fed nutritional treatments including cactus performed similarly to those receiving diets including conventional concentrate feeds. 相似文献
182.
Johnson RD Yannoni CS Dorn HC Salem JR Bethune DS 《Science (New York, N.Y.)》1992,255(5049):1235-1238
The rotational dynamics of C(60) in the solid state have been investigated with carbon-13 nuclear magnetic resonance ((13)C NMR). The relaxation rate due to chemical shift anisotropy (1/9T1(CSA)(1)) was precisely measured from the magnetic field dependence of T(1), allowing the molecular reorientational correlation time, tau, to be determined. At 283 kelvin, tau = 9.1 picoseconds; with the assumption of diffusional reorientation this implies a rotational diffusion constant D = 1.8 x 10(10) per second. This reorientation time is only three times as long as the calculated tau for free rotation and is shorter than the value measured for C(60) in solution (15.5 picoseconds). Below 260 kelvin a second phase with a much longer reorientation time was observed, consistent with recent reports of an orientational phase transition in solid C(60). In both phases tau showed Arrhenius behavior, with apparent activation energies of 1.4 and 4.2 kilocalories per mole for the high-temperature (rotator) and low-temperature (ratchet) phases, respectively. The results parallel those found for adamantane. 相似文献
183.
Adegbeye Moyosore J. Asaniyan Emmanuel K. Igbalajobi Olabisi A. Oyedele Damilola S. Elghandour Mona M. M. Y. Salem Abdelfattah Z. M. Falade Temilola T. 《Tropical animal health and production》2020,52(3):1005-1012
Tropical Animal Health and Production - The immergence of antibiotic resistance, in livestock especially poultry, led to the ban of antibiotics as a growth promoter in some part of the world. This... 相似文献
184.
V.E. Anuradha Mohamed A. Salem R. Panneerselvam 《Pesticide biochemistry and physiology》2010,98(2):312-316
In this study, 5 μM ABA and GA3 concentration were used to study the effect of these growth regulators on the andrographolide content and antioxidant potentials of Andrographis paniculata. The growth regulators were applied by means of foliar spray during morning hours. A significant enhancement in non-enzymatic antioxidant contents was observed in all sampling days in A.paniculata plants under ABA and GA3 treatments. Ascorbic acid and α-tocopherol content was increased significantly under the growth regulator treatments in leaves, stem and roots of A. paniculata. The activities of antioxidant enzymes such as ascorbate peroxidase, superoxide dismutase and catalase were increased by ABA and GA3 treatments in the leaves, stem and roots of A. paniculata plants. The HPLC analysis was used to quantify the andrographolide content in control and growth regulator treated plants. The growth regulators ABA and GA3 treated plants showed increased contents of andrographolide when compared to control. 相似文献