全文获取类型
收费全文 | 1219篇 |
免费 | 42篇 |
国内免费 | 3篇 |
专业分类
林业 | 94篇 |
农学 | 57篇 |
基础科学 | 16篇 |
217篇 | |
综合类 | 79篇 |
农作物 | 129篇 |
水产渔业 | 132篇 |
畜牧兽医 | 398篇 |
园艺 | 24篇 |
植物保护 | 118篇 |
出版年
2023年 | 14篇 |
2022年 | 42篇 |
2021年 | 55篇 |
2020年 | 71篇 |
2019年 | 61篇 |
2018年 | 46篇 |
2017年 | 51篇 |
2016年 | 48篇 |
2015年 | 50篇 |
2014年 | 51篇 |
2013年 | 102篇 |
2012年 | 79篇 |
2011年 | 93篇 |
2010年 | 43篇 |
2009年 | 24篇 |
2008年 | 54篇 |
2007年 | 49篇 |
2006年 | 29篇 |
2005年 | 26篇 |
2004年 | 32篇 |
2003年 | 27篇 |
2002年 | 23篇 |
2001年 | 10篇 |
2000年 | 11篇 |
1999年 | 10篇 |
1997年 | 5篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1991年 | 10篇 |
1990年 | 7篇 |
1989年 | 12篇 |
1988年 | 8篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1981年 | 6篇 |
1979年 | 5篇 |
1976年 | 4篇 |
1975年 | 7篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1971年 | 5篇 |
1970年 | 5篇 |
1969年 | 4篇 |
1967年 | 2篇 |
1966年 | 3篇 |
排序方式: 共有1264条查询结果,搜索用时 15 毫秒
51.
A new eudesmanolide, 1beta,9alpha-dihydroxyeudesm-3-en-5beta,6alpha,7alpha,11alphaH-12,6-olide (1), was isolated from Crataegus flava fruits. Its structure was determined by spectroscopic methods. 相似文献
52.
Zaheer Ahmed Ian J. Tetlow Duane E. Falk Qiang Liu Michael J. Emes 《Cereal Chemistry》2016,93(6):618-630
Physical properties of resistant starch (RS) were examined in a range of barley genotypes to determine the contribution of starch and seed physical characteristics to the RS component. Thirty‐three barley genotypes were studied, which varied significantly in their RS, amylose, and starch contents and grain yield. From 33 genotypes, 13 exhibiting high RS were selected for detailed physicochemical analysis of starch. In high‐RS varieties, granule size and number were unimodal, compared with normal starches from a reference genotype, which showed a bimodal distribution. Principal component analysis (PCA) showed that a higher content of granules <15 µm was positively correlated with RS and amylose content, whereas the proportion of granules 15–45 µm was negatively correlated with the RS and amylose contents. Physical fractionation of starches by centrifugation into different population sizes demonstrated that size alone is not an accurate indicator of the population of A‐type and B‐type granules within a given genotype. PCA also showed that large 15–45 µm granules were positively correlated with seed thickness and that thousand grain weight was positively correlated with seed width. High‐RS and high‐amylose genotypes showed variation in overall yield and starch content, with some genotypes showing yield comparable to the reference genotype. Analysis of amylopectin chain length distribution showed that high amylose or RS content was not associated with a higher proportion of amylopectin long chains when compared with either waxy or reference (normal) barley genotypes. This study highlights useful markers for screening barley genotypes with favorable starch characteristics. 相似文献
53.
Associate Professors S. M. Ahmed Associate Professors A. A. Abdel-Gawaad 《Journal of pest science》1975,48(10):148-150
Laboratory and field trials with two synthetic Juvenil Hormone Analogues on four Aphid species Two juvenile hormone analogues (JHA) were applied in laboratory in three different concentrations to four aphid species. Mortality-concentrations and mortality-time for the lowest concentration were plotted on logprobit paper and the slope calculated from the eye fitted lines. The results indicated the feasibility of probit analysis for concentration-mortality or time mortality responses. However in one of the aphid species i. e.Aphis gossypii, there was a lack of linearity in the relationship, this species proved to be tolerant to JHA in field trials. Both JHA supressed progeny production, the supression was found to be selective to different species. In field trials both JHA brought about appreciable reductions in the populations with the exception ofAphis gossypii. The colour ofH. arundinis was found to differ in adults insuing from treated nymphs, otherwise no remarkable morphonogenic changes were observed. 相似文献
54.
The crude extract of Mikania cordata (1 and 3 g/kg, p.o.) and deoxymikanolide (1) (10 mg/kg, p.o.) significantly inhibited acetic acid-induced writhing in mice. Three other sesquiterpene dilactones isolated from the same plant, namely mikanolide, dihydromikanolide and scandenolide, did not show significant analgesic activity. 相似文献
55.
Effects of supplementation with green tea by‐products on growth performance,meat quality,blood metabolites and immune cell proliferation in goats 下载免费PDF全文
S. T. Ahmed J.‐W. Lee H.‐S. Mun C.‐J. Yang 《Journal of animal physiology and animal nutrition》2015,99(6):1127-1137
Forty‐eight castrated male goats were used to determine the effects of feeding green tea by‐products (GTB) on growth performance, meat quality, blood metabolites and immune cell proliferation. Experimental treatments consisted of basal diets supplemented with four levels of GTB (0%, 0.5%, 1.0% or 2.0%). Four replicate pens were assigned to each treatment with three goats per replicate. Increasing dietary GTB tended to linearly increase the overall average weight gain and feed intake (p = 0.09). Water holding capacity, pH and sensory attributes of meat were not affected by GTB supplementation, while cooking loss was reduced both linearly and quadratically (p < 0.01). The redness (linear; p = 0.02, quadratic; p < 0.01) and yellowness (quadratic; p < 0.01) values of goat meat were improved by GTB supplementation. Increasing dietary GTB quadratically increased protein and decreased crude fat (p < 0.05), while linearly decreased cholesterol (p = 0.03) content of goat meat. The proportions of monounsaturated fatty acid, polyunsaturated fatty acid (PUFA) and n‐6 PUFA increased linearly (p < 0.01) and n‐3 PUFA increased quadratically (p < 0.05) as GTB increased in diets. Increasing dietary GTB linearly increased the PUFA/SFA (saturated fatty acid) and tended to linearly and quadratically increase (p ≤ 0.10) the n‐6/n‐3 ratio. The thiobarbituric acid‐reactive substances values of meat were lower in the 2.0% GTB‐supplemented group in all storage periods (p < 0.05). Dietary GTB linearly decreased plasma glucose and cholesterol (p < 0.01) and quadratically decreased urea nitrogen concentrations (p = 0.001). The growth of spleen cells incubated in concanavalin A and lipopolysaccharides medium increased significantly (p < 0.05) in response to GTB supplementation. Our results suggest that GTB may positively affect the growth performance, meat quality, blood metabolites and immune cell proliferation when supplemented as a feed additive in goat diet. 相似文献
56.
Effect of Mediterranean saltbush (Atriplex halimus) ensilaging with two developed enzyme cocktails on feed intake,nutrient digestibility and ruminal fermentation in sheep 下载免费PDF全文
Haidy Alsersy Abdelfattah Z. M. Salem Borhami E. Borhami Jaime Olivares Hany M. Gado Maria D. Mariezcurrena Mohamed H. Yacuot Ahmed E. Kholif Mounir El‐Adawy Saul R. Hernandez 《Animal Science Journal》2015,86(1):51-58
The aim of this study was to assess the effects of feeding Atriplex halimus (AH) silage treated with two developed enzyme cocktails to sheep on feed intake, nutrient digestibility and ruminal fermentation. The AH silage was treated without or with 2 L of ZAD1® or ZAD2®/1000 kg with 5% molasses and ensiled for 30 days. Barley grain (300 g/head/day) was fed as an energy supplement once daily at 10.00 hours and AH silage with or without enzyme treatment was offered ad libitum to animals twice daily at 09.00 and 16.00 hours. Sheep were fed on four experimental forage diets comprised of AH silage and barley (D1), AH silage treated with ZAD1® and barley (D2), AH silage treated with ZAD2® and barley (D3) and AH silage treated with a combination of ZAD1® and ZAD2® (1:1) and barley (D4). Ensiling AH with enzymes reduced its contents of neutral detergent fiber and acid detergent fiber. The dry matter intake of AH of D2, D3 and D4 decreased (P < 0.001) as compared to D1. However, enzyme‐treated diets had greater total digestible nutrients intake (P < 0.001) as compared to D1. The nutrients digestibility for D2, D3 and D4 were higher than those for D1 (P < 0.001), and were higher for D3 as compared to both D2 and D4. Sheep fed on D3 had highest (P < 0.001) ruminal total volatile fatty acids concentration, ammonia nitrogen concentration and microbial protein yield. It could be concluded that AH silage treated with ZAD1® or ZAD2® improved digestibility and rumen fermentation in sheep. 相似文献
57.
Effect of feeding Aspergillus awamori and canola seed on the growth performance and muscle fatty acid profile in broiler chicken 下载免费PDF全文
The aim of this study was to examine effects of dietary supplementation with Aspergillus awamori and feeding canola seed on the growth and fatty acid profile in broilers. Twenty‐eight chicks (15 days old) were assigned to the following groups: (1) control, fed a basal diet; (2) awamori, fed the basal diet supplemented with 0.05% A. awamori; (3) canola, fed a diet containing 5% canola seed; and (4) canola + awamori, fed the canola diet supplemented with A. awamori (seven birds/group). Body weight gain was increased by A. awamori but not influenced by canola seed. Breast muscle weight was increased in either awamori or canola groups. Although plasma triglyceride and cholesterol were decreased by feeding A. awamori or canola seed, fat content in the breast muscle were increased, accompanied by decrease in saturated fatty acids and increase in unsaturated fatty acids. Moreover, decreased thiobarbituric acid reactive substance and increased α‐tocopherol content in the breast muscle was observed in all experimental groups. In conclusion, these results suggested that feeding canola seed and A. awamori might improve growth performance, and modified muscle fatty acid profile and α‐tocopherol content, suggesting that they may improve meat quality. 相似文献
58.
Tetsuji Ota Tsuyoshi Kajisa Nobuya Mizoue Shigejiro Yoshida Gen Takao Yasumasa Hirata Naoyuki Furuya Takio Sano Raul Ponce-Hernandez Oumer S. Ahmed Heng Sokh Vuthy Ma Eriko Ito Jumpei Toriyama Yukako Monda Hideki Saito Yoshiyuki Kiyono Sophal Chann Nang Ket 《Journal of Forest Research》2015,20(6):484-492
59.
Ahmed NE Farag MM Soliman KM Abdel-Samed AK Naguib KhM 《Journal of agricultural and food chemistry》2007,55(23):9576-9580
A comparative study was conducted to evaluate four previously reported methods that proved to have a recovery greater than 80% for the determination of different levels of ochratoxin A (OTA) in green and roasted coffee beans and to select an accurate, sensitive, and less-expensive technique between the existing methods. The results indicated that the Association of Official Analytical Chemists (AOAC) official method for the extraction of OTA in green coffee and determination by high-performance liquid chromatography (HPLC) is recommended as an efficient method for the routine analyses of OTA in green and ground roasted coffee beans. This method proved to be an accurate, sensitive, and less-expensive method that employs routine materials and available equipment. Although the immunoaffinity column/HPLC procedure tested showed a significantly higher percentage than the AOAC recommended method, it is recommended for use in processed coffee beans where low concentrations of OTA may be expected to be detected. 相似文献
60.
Desneux Nicolas Han Peng Mansour Ramzi Arn Judit Brvault Thierry Campos Mateus R. Chailleux Anais Guedes Raul N. C. Karimi Javad Konan Kouassi Arthur J. Lavoir Anne-violette Luna Mara G. Perez-Hedo Meritxell Urbaneja Alberto Verheggen Franois J. Zappal Lucia Abbes Khaled Ali Abid Bayram Yunus Cantor Fernando Cuthbertson Andrew G. S. De Vis Raf Erler Fedai Firake Dnyaneshwar M. Haddi Khalid Hajjar M. Jamal Ismoilov Khasan Jaworski Coline C. Kenis Marc Liu Hao-tian Madadi Hossein Martin Thibaud Mazih Ahmed J. Messelink Gerben Mohamed Samira A. Nofemela Robert S. Oke Abiola Ramos Csar Ricupero Michele Roditakis Emmanouil Shashank Pathour R. Wan Fang-Hao Wang Ming-hui Wang Su Zhang Yi-Bo Biondi Antonio 《Journal of pest science》2022,95(1):17-39
Journal of Pest Science - The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), has invaded most Afro-Eurasian countries and is threatening worldwide tomato... 相似文献