全文获取类型
收费全文 | 484篇 |
免费 | 52篇 |
国内免费 | 49篇 |
专业分类
林业 | 6篇 |
农学 | 13篇 |
基础科学 | 1篇 |
67篇 | |
综合类 | 152篇 |
农作物 | 6篇 |
水产渔业 | 70篇 |
畜牧兽医 | 256篇 |
园艺 | 5篇 |
植物保护 | 9篇 |
出版年
2024年 | 1篇 |
2023年 | 17篇 |
2022年 | 23篇 |
2021年 | 19篇 |
2020年 | 26篇 |
2019年 | 47篇 |
2018年 | 15篇 |
2017年 | 39篇 |
2016年 | 31篇 |
2015年 | 30篇 |
2014年 | 24篇 |
2013年 | 31篇 |
2012年 | 39篇 |
2011年 | 20篇 |
2010年 | 26篇 |
2009年 | 22篇 |
2008年 | 16篇 |
2007年 | 30篇 |
2006年 | 29篇 |
2005年 | 18篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 10篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1979年 | 2篇 |
1956年 | 1篇 |
排序方式: 共有585条查询结果,搜索用时 78 毫秒
11.
L. FENG H.‐H. HUANG Y. LIU J. JIANG W.‐D. JIANG K. HU S.‐H. LI X.‐Q. ZHOU 《Aquaculture Nutrition》2011,17(5):557-569
This study was to investigate the effect of dietary thiamin on the immune response and intestinal microflora in juvenile Jian carp (Cyprinus carpio var. Jian). Seven diets (0.25, 0.48, 0.79, 1.06, 1.37, 1.63 and 2.65 mg thiamin kg?1) were fed to Jian carp (8.20 ± 0.02 g). At the end of feeding trial, red blood cell counts and white blood cell counts increased with increasing dietary thiamin levels up to 0.79 and 1.06 mg kg?1 diet, respectively (P < 0.05); Lactobacillus counts in intestine increased gradually, and maximum values obtained when the thiamin level was at 0.79 mg kg?1 diet (P < 0.05). After the feeding trial, fish were injected with Aeromonas hydrophila only one time on the first day of the challenge trial and fed the same diets as the growth trial for 17 days. The survival rate, leucocyte phagocytic activity, lectin potency, acid phosphatase activity, lysozyme activity, total iron‐binding capacity and immunoglobulin M content of fish after being injected with A. hydrophila were all improved with increasing dietary thiamin levels up to a point, respectively (P < 0.05). These results suggested that thiamin could improve immune response and the balance of intestinal microflora of juvenile Jian carp. 相似文献
12.
13.
【目的】 探究丁酸梭菌在肉鸡消化道内的定植能力以及丁酸梭菌对肉鸡肠道短链脂肪酸含量和菌群多样性的影响。【方法】 选择90只健康状况良好的1日龄爱拔益加肉鸡,随机均分为空白组和丁酸梭菌组,每组3个重复,每个重复15只鸡。空白组灌喂生理盐水,丁酸梭菌组灌服荧光标记的丁酸梭菌,3 h及16日龄进行解剖并采集回肠上皮细胞观察荧光情况。随后另外选择30只健康状况良好的1日龄雏鸡,随机分为对照组和试验组,试验组1~6 d饲喂含丁酸梭菌的饲粮,之后饲喂基础饲粮,对照组全程饲喂基础饲粮,试验期21 d。在16和21日龄时,分别采集回肠和盲肠中段内容物,测定乙酸、丙酸、异丁酸、丁酸、异戊酸、戊酸、己酸和总短链脂肪酸含量,并进行微生物种类、物种丰度比例、菌属以及蛋白功能丰度等差异分析。【结果】 3 h及16日龄丁酸梭菌组回肠上皮细胞周围均呈现出荧光现象,表明丁酸梭菌能够定植于消化道上皮细胞。短链脂肪酸含量测定结果显示,与对照组相比,在肉鸡回肠内容物中,试验组16日龄乙酸、丙酸、异丁酸、异戊酸和戊酸含量均极显著增加(P<0.01);21日龄丙酸、异戊酸和戊酸含量均极显著增加(P<0.01),乙酸、异丁酸和总短链脂肪酸含量均显著增加(P<0.05);在盲肠内容物中,试验组16日龄肉鸡丁酸和戊酸含量均极显著增加(P<0.01),异戊酸和己酸含量显著增加(P<0.05);21日龄丁酸和异戊酸均极显著增加(P<0.01),乙酸、异丁酸、己酸和总短链脂肪酸均显著增加(P<0.05)。门水平上微生物种类分析发现,16日龄样本中厚壁菌门为优势菌群,丰度最高;21日龄样本中微生物种类增多,其中变形菌门、厚壁菌门和拟杆菌门为优势菌群,丰度较高,16和21日龄试验组的优势菌群均高于对照组。物种丰度比例分析结果显示,与对照组相比,16日龄试验组厌氧菌属的物种丰度比例显著增加(P<0.05),而去氟球菌属、丛毛单胞菌属、肠杆菌属等7种菌属的物种丰度比例显著降低(P<0.05);21日龄试验组铁杆菌属、毛球菌属等6种菌属的物种丰度比例显著增加(P<0.05),变形菌属、浮霉菌属、装甲菌门GP5的物种丰度属显著降低(P<0.05)。菌属差异分析结果显示,16日龄试验组起重要作用的微生物是布劳特氏菌属,对照组起重要作用的微生物是梭状芽孢杆菌属和未分类毛螺旋菌属;21日龄试验组起重要作用的微生物是未分类拟杆菌、毛球菌属、乳酸杆菌目、乳球菌属等,对照组起重要作用的微生物是诺兰克酸杆菌GP4、丛毛单胞菌科等。菌群蛋白功能丰度分析结果显示,16日龄试验组甲基受体趋化性蛋白、谷胱甘肽S-转移酶、氨基酸转移酶亚基A的丰度均高于对照组,21日龄试验组ECF亚家族RNA聚合酶δ-70因子、丙氨酸的丰度均高于对照组。【结论】 丁酸梭菌可以在肉鸡回肠上皮细胞中定植;丁酸梭菌可增加肠道内容物中短链脂肪酸含量、微生物种类及有益菌属,提高物种丰度及功能蛋白丰度,从而促进肠道功能发挥。 相似文献
14.
采用中温(35±1℃)UASB AF相结合的反应器处理碱法草浆造纸蒸煮黑液,设计了两种试验方案。试验方案Ⅰ-碱法草浆黑液酸化后进行厌氧发酵,Ⅰ号反应器内装陶粒。试验方案Ⅱ-黑液用化学法(HCl)去除木质素后进行厌氧发酵,Ⅱ号反应器内装软填料。进行HRT、有机负荷和有机污染物(COD_(cr)、BOD_5)去除效率、沼气产气率相关性试验。在厌氧发酵稳态运行条件下,采用Hungate厌氧操作技术,MPN计数法对UASB AF反应器内厌氧污泥中的主要微生物类群区系组成进行了生态分析研究。 相似文献
15.
16.
芽孢乳杆菌对肉仔鸡生产性能、肠道发育和微生物菌群的影响 总被引:1,自引:0,他引:1
本试验旨在研究不同水平芽孢乳杆菌对内仔鸡生产性能、肠道发育及微生物菌群的影响.选取1日龄爱拔益加(AA)肉仔鸡2 400只,随机分为4组(每组6个重复,每个重复100只):对照组饲喂基础饲粮,试验组饲喂分别添加200、100和50 mg/kg芽孢乳杆菌的试验饲粮,试验期42 d.结果表明:1)饲粮添加200 mg/kg... 相似文献
17.
We investigated the effect of probiotics from anaerobic microflora with prebiotics (synbiotics) on growth performance, noxious gas emission and fecal pathogenic bacteria populations in growing pigs. The basal diet, which contained approximately 25% corn, 24% whey, 12% wheat and 12% soybean meal, was supplemented alternatively with 0.15% antibiotics (US diet), prebiotics and 0.2% probiotics from anaerobic bacteria (BS diet), yeast (YS diet), mold (MS diet) or compounds (CS diet). One hundred and fifty pigs were fed an experimental diet for 15 days. Although the growth performance was not affected by supplemental synbiotics, the BS group showed higher dry matter and crude protein digestibility. The BS group decreased fecal ammonia and amine gas emissions, and increased fecal acetate gas emission compared with the US group. All synbiotics groups decreased in fecal propionate gas emission. Fecal Escherichia coli population was lower in the synbiotics groups than in the US group. Therefore, the results of the present study suggest that synbiotics exert similar effects with antibiotics on the nutrient digestibility and fecal microflora composition in growing pigs. Moreover, synbiotics can also decrease the fecal noxious gas emission in growing pigs. 相似文献
18.
Eberhard Thalmann 《Archives of Agronomy and Soil Science》2013,59(6):507-508
A crop rotation field study with manure application was established at Tartu in 1985. Biological and chemical properties were evaluated on fine sandy loam Podzoluvisol in May 1989. The treatments included unmanured (No and N80) controls, two peat based composts and five manures of different origin. The procedures of the most probable number (MPN) and spread plate counts were used for microbiological investigation, but also enzymatic activities, nitrogen forms, total‐C and pH were simultaneously estimated in plough layer soil. The most variable i.e. the most clearly differentiated physiological groups within manures were cellulolytic and ammonifying bacteria followed by Azotobacter spp. together with actinomycetes. Abundance of aerobic cellulolytic and ammonifying bacteria correlated positively with the number of soil algae and fungi, and negatively with nitrate‐ and nitrite‐reductase. The number of actinomycetes correlated positively with urease and catalase activity. Soil enzymatic activity was mainly modified by nitrite‐reductase. Peat composts had the highest C‐content and highest pH value compared with other soils. Pig slurry and NH4NO3 (N80) treatment had the highest level of fixed NH+ 4 ‐ions in soil. Nine months after manure application no differences were found in the unstable NO– 3content of soil. Variation in the number of the studied microbial physiological groups between treatments remained insignificant. 相似文献
19.
20.
饲喂乳杆菌雏鸡对鸡白痢菌感染的影响 总被引:5,自引:0,他引:5
雏鸡饲喂乳杆菌培养物后,人工感染鸡白痢沙门氏菌,观察雏鸡盲肠主要正常菌群定植及雏鸡抵抗力情况。研究结果表明:人工感染鸡白痢沙门氏菌后,饲喂乳杆菌组同未饲喂乳杆菌组相比,雏鸡盲肠内正常菌群有一定变化,大肠杆菌数明显降低(P<001),双歧杆菌和乳杆菌数明显增加(P<001),而且死亡率降低20%。 相似文献