全文获取类型
收费全文 | 781篇 |
免费 | 76篇 |
国内免费 | 38篇 |
专业分类
林业 | 10篇 |
农学 | 14篇 |
基础科学 | 1篇 |
5篇 | |
综合类 | 145篇 |
农作物 | 4篇 |
水产渔业 | 115篇 |
畜牧兽医 | 589篇 |
园艺 | 9篇 |
植物保护 | 3篇 |
出版年
2024年 | 1篇 |
2023年 | 17篇 |
2022年 | 17篇 |
2021年 | 38篇 |
2020年 | 40篇 |
2019年 | 46篇 |
2018年 | 26篇 |
2017年 | 38篇 |
2016年 | 46篇 |
2015年 | 39篇 |
2014年 | 45篇 |
2013年 | 43篇 |
2012年 | 38篇 |
2011年 | 57篇 |
2010年 | 48篇 |
2009年 | 66篇 |
2008年 | 33篇 |
2007年 | 43篇 |
2006年 | 45篇 |
2005年 | 23篇 |
2004年 | 18篇 |
2003年 | 22篇 |
2002年 | 20篇 |
2001年 | 12篇 |
2000年 | 7篇 |
1999年 | 12篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 9篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
排序方式: 共有895条查询结果,搜索用时 46 毫秒
91.
92.
Velarde R Mentaberre G Sánchez J Marco I Lavín S 《Veterinary journal (London, England : 1997)》2008,177(3):445-447
Gastrointestinal mesenchymal tumours from two Spanish ibex (Capra pyrenaica hispanica) were examined grossly, histologically and immunohistochemically. One neoplasm was a 1.5 kg tan multinodular cavitated mass in the forestomach. The other tumour was a firm mural mass 1.2 cm in diameter in the colon. Microscopically, both tumours were formed mainly by spindle shaped cells arranged in closely packed interlacing fascicles. Neoplastic cells in both tumours labelled positively for KIT (CD117), vimentin and alpha-smooth muscle actin. These findings suggest that both neoplasms were gastrointestinal stromal tumours and most likely to be derived from the interstitial cells of Cajal or their progenitor cells. 相似文献
93.
Cytology of tracheal aspirates, tracheal endoscopic and blood tests were carried out to
86 Thoroughbred racehorses presenting coughs or poor performance which were suspected to
have lower respiratory tract disease (LRTD) to assess the conditions of the disorders.
Racehorses were classified into coughing (66 horses) and non-coughing (20 horses) groups
based on clinical symptoms. Nine Thoroughbred racehorses without respiratory abnormality
were used as controls. Assessment of grades of airway mucus, cytology of tracheal
aspirates and serum amyloid A (SAA), fibrinogen (Fbg) and pulmonary surfactant protein D
(SP-D) measurements were performed. Relationships between age, gender and racing careers
were also investigated to understand the characteristics of LRTD in racehorses. Mean age
was significantly higher in non-coughing group compared to coughing group. Existence of
racing career and number of starts were significantly greater in non-coughing group
compared to coughing group. On the other hand, grades of airway mucus were significantly
higher in coughing group compared to control group. Percentages of neutrophils in tracheal
aspirates were significantly higher in coughing group compared to non-coughing and control
groups. SAA, Fbg and SP-D were higher in coughing group compared to non-coughing and
control groups indicating that condition of coughing group is in the acute phase. Positive
rate of inflammatory airway disease was significantly higher in coughing and non-coughing
groups compared to control group. It was concluded that carrying out comprehensive
evaluation including investigation on SAA, Fbg and SP-D analysis with airway assessment to
Thoroughbred racehorses which were suspected to have LRTD are useful procedure to
understand the pathological condition which aid to initiate appropriate treatment,
prognosis judgment or to advise trainers to consider altering training regimen. 相似文献
94.
95.
通过测定生殖道黏液导电性确定小尾寒羊配种时机的观察研究 《畜牧与饲料科学》2019,40(12):54-57
通过使用羊排卵测定仪准确掌握不同繁殖期小尾寒羊的排卵期,旨在有效提高母羊的受孕率。选择1.5~3.5周岁和4~6周岁小尾寒羊空怀期繁殖母羊各30只,利用羊排卵测定仪测定发情期内母羊生殖道黏液电阻值,研究其变化规律,发现1.5~3.5周岁母羊组发情持续时间较短,电阻值下降和上升均较快;而4~6周岁母羊组发情持续时间较长,电阻值下降较快但其上升曲线较为曲折。比较处于不同阴道黏液电阻值范围的母羊人工授精后的受孕率发现,4~6周岁的羊群组比1.5~3.5周岁的羊群组可受孕范围宽,但1.5~3.5周岁的羊群组在可受孕电阻值范围内受孕率明显高于4~6周岁的羊群组。该研究结果提示,不同年龄小尾寒羊母羊阴道黏液电阻值变化幅度不同,发情周期内电阻值下降到最低点后再上升时期为小尾寒羊的排卵期,适宜配种,该时期为母羊配种受孕率高。 相似文献
96.
97.
98.
A study was carried out to investigate whether adding a starter culture or a formic acid containing-product to fermented liquid feed of suboptimal microbial quality could improve the characteristics of the mixture and the gastrointestinal ecology and growth performance of piglets. Four experimental diets were prepared: Feed and water were mixed in the ratio 1:2.5 (w/w) in four closed tanks. Diet 1) Three times daily, 50% of the mixture stored in the tank was removed and then replaced with an equal amount of fresh feed and water, (FLF), positive control; Diet 2) Three times daily, 95% of the mixture stored in the tank was removed and then replaced with an equal amount of fresh feed and water. Escherichia coli K12 (1 × 106/g) was added every morning (COLI); Diet 3) as the COLI treatment and added Lactobacillus plantarum VTT E-78076 (1 × 106/g) every morning (+PLANTARUM); and Diet 4) as the COLI treatment and added 0.26 g AIV/KemiSile 2 plus/100 g mixture three times daily (+ACID). One hundred and sixty weaners were used. On day 14, one littermate from each pen was killed and the gastrointestinal tract removed. The remaining piglets were used to measure the effect of the experimental diets on growth performance during the first six weeks post-weaning. The +ACID diet had lower numbers of lactic acid bacteria and Enterobacteriaceae, higher numbers of yeasts, and lower concentration of lactic acid and acetic acid than the COLI and +PLANTARUM diets. Feeding the +PLANTARUM and the +ACID diets increased daily weight gain during the six weeks post-weaning (P ≤ 0.02) compared to feeding the COLI diet. The +ACID group showed the highest numerical daily feed intake in all periods. The gain/feed during the six weeks post-weaning tended to be lowest in the COLI group (P < 0.10). The counts of lactic acid bacteria able to grow at 20 °C were lowest in the stomach (P ≤ 0.003) and distal small intestine (P ≤ 0.06) of the +ACID group. The counts of yeasts able to grow at 37 °C in the stomach were highest in the +ACID (P ≤ 0.01) and FLF groups (P ≤ 0.09). The number of yeasts able to grow at 20 °C in the stomach and distal small intestine was highest in the FLF fed piglets, followed by the +ACID group. This study showed that addition of L. plantarum VTT E-78076 or AIV/KemiSile 2 plus to fermented liquid feed of suboptimal microbial quality improved growth performance without affecting the gastrointestinal ecology of piglets substantially. 相似文献
99.
100.
本文旨在讨论表皮生长因子(EGF)对葡聚糖硫酸钠(DSS)诱导的结肠炎模型小鼠肠道损伤的修复作用。选用24只6周龄BALB/c小鼠,随机分为3组,即:正常对照组、DSS模型对照组、DSS+EGF组。正常对照组小鼠饮用自来水;DSS模型对照组小鼠在试验第1~7天饮用5%DSS水溶液,第8~10天饮用自来水;DSS+EGF组小鼠按照DSS模型对照组处理,同时每天皮下注射EGF 2次,共注射10 d。结果表明:1)与正常对照组相比,DSS模型对照组小鼠结肠长度极显著降低(P0.01);与DSS模型对照组相比,DSS+EGF组小鼠结肠长度极显著增加(P0.01)。2)DSS模型对照组小鼠结肠可见典型溃疡,结肠损伤程度评分(CDS)极显著高于正常对照组(P0.01);DSS+EGF组小鼠结肠组织未见溃疡,与DSS模型对照组相比,CDS极显著降低(P0.01)。3)与正常对照组相比,DSS模型对照组小鼠结肠紧密连接蛋白(Occludin)浓度显著降低(P0.05);与DSS模型对照组相比,DSS+EGF组小鼠结肠Occludin浓度显著升高(P0.05)。4)与正常对照组相比,DSS模型对照组小鼠结肠白细胞介素-2(IL-2)和白细胞介素-4(IL-4)浓度极显著降低(P0.01),白细胞介素-10(IL-10)浓度显著降低(P0.05);与DSS模型对照组相比,DSS+EGF组结肠IL-2和IL-4浓度极显著增加(P0.01),IL-10浓度显著增加(P0.05)。由此可见,EGF可能通过提高肠道Occludin表达水平,调节肠道细胞因子浓度趋于正常水平,从而修复受损肠道组织,维持肠道黏膜屏障的完整性。 相似文献