全文获取类型
收费全文 | 496篇 |
免费 | 21篇 |
专业分类
林业 | 41篇 |
农学 | 6篇 |
基础科学 | 6篇 |
92篇 | |
综合类 | 57篇 |
农作物 | 12篇 |
水产渔业 | 34篇 |
畜牧兽医 | 214篇 |
园艺 | 14篇 |
植物保护 | 41篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2021年 | 14篇 |
2020年 | 12篇 |
2019年 | 15篇 |
2018年 | 15篇 |
2017年 | 11篇 |
2016年 | 17篇 |
2015年 | 14篇 |
2014年 | 15篇 |
2013年 | 19篇 |
2012年 | 33篇 |
2011年 | 40篇 |
2010年 | 23篇 |
2009年 | 18篇 |
2008年 | 36篇 |
2007年 | 38篇 |
2006年 | 38篇 |
2005年 | 36篇 |
2004年 | 26篇 |
2003年 | 21篇 |
2002年 | 31篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有517条查询结果,搜索用时 0 毫秒
1.
2.
Dr Mike Bond 《Australian veterinary journal》2005,83(4):192-192
3.
影响猪生产性能的三个重要元素(遗传、健康和营养)之间的无法解脱的联系决定了养猪生产的成功或失败.一个永恒的三角关系(图1)将它们连在一起,并且在此关系中每一个元素会持续地影响其它二个中的每一个.健康是这三者中最难以定量的一个,往往也是此三角关系中最为薄弱的环节.能够改善此薄弱环节的计划和重视猪群健康的打算将会提高猪的总体生产性能. 相似文献
4.
Hillenmeyer ME Fung E Wildenhain J Pierce SE Hoon S Lee W Proctor M St Onge RP Tyers M Koller D Altman RB Davis RW Nislow C Giaever G 《Science (New York, N.Y.)》2008,320(5874):362-365
Genetics aims to understand the relation between genotype and phenotype. However, because complete deletion of most yeast genes ( approximately 80%) has no obvious phenotypic consequence in rich medium, it is difficult to study their functions. To uncover phenotypes for this nonessential fraction of the genome, we performed 1144 chemical genomic assays on the yeast whole-genome heterozygous and homozygous deletion collections and quantified the growth fitness of each deletion strain in the presence of chemical or environmental stress conditions. We found that 97% of gene deletions exhibited a measurable growth phenotype, suggesting that nearly all genes are essential for optimal growth in at least one condition. 相似文献
5.
MacArthur DG Balasubramanian S Frankish A Huang N Morris J Walter K Jostins L Habegger L Pickrell JK Montgomery SB Albers CA Zhang ZD Conrad DF Lunter G Zheng H Ayub Q DePristo MA Banks E Hu M Handsaker RE Rosenfeld JA Fromer M Jin M Mu XJ Khurana E Ye K Kay M Saunders GI Suner MM Hunt T Barnes IH Amid C Carvalho-Silva DR Bignell AH Snow C Yngvadottir B Bumpstead S Cooper DN Xue Y Romero IG; Genomes Project Consortium Wang J Li Y Gibbs RA McCarroll SA Dermitzakis ET Pritchard JK Barrett JC 《Science (New York, N.Y.)》2012,335(6070):823-828
Genome-sequencing studies indicate that all humans carry many genetic variants predicted to cause loss of function (LoF) of protein-coding genes, suggesting unexpected redundancy in the human genome. Here we apply stringent filters to 2951 putative LoF variants obtained from 185 human genomes to determine their true prevalence and properties. We estimate that human genomes typically contain ~100 genuine LoF variants with ~20 genes completely inactivated. We identify rare and likely deleterious LoF alleles, including 26 known and 21 predicted severe disease-causing variants, as well as common LoF variants in nonessential genes. We describe functional and evolutionary differences between LoF-tolerant and recessive disease genes and a method for using these differences to prioritize candidate genes found in clinical sequencing studies. 相似文献
6.
7.
Steagall PV Mantovani FB Taylor PM Dixon MJ Luna SP 《Veterinary journal (London, England : 1997)》2009,182(2):203-209
The dose-related antinociceptive effects of intravenous (IV) buprenorphine were evaluated in cats. Thermal (TT) and mechanical threshold (MT) devices were used for nociceptive stimulation. After baseline threshold recordings, buprenorphine was administered IV (0.01, 0.02 or 0.04 mg/kg; B1, B2 and B4, respectively) in a randomised, blinded and cross-over study. Data were analysed by ANOVA (P < 0.05) using 95% confidence intervals (CI). TT increased 15, 30, 45 min and 1 (5.2 ± 2.7 °C), 2, 3 and 4 h after B1; 15, 30, 45 min and 1 (5.1 ± 3.9 °C) and 2 h after B2, and 15, 30, 45 min and 1 (5.4 ± 3.3 °C), 2, 3, 6 and 8 h after B4. MT increased 15 and 45 min after B2 (260 ± 171 mmHg), and 30 (209 ± 116 mmHg) and 45 min and 1 and 2 h after B4. At 45 min, MT values were significantly higher after B2 compared to B1 (P < 0.05). With MT, B2 and B4 produced more antinociception and longer duration of action than B1, respectively. No dose response to thermal stimulation was detected. 相似文献
8.
Oyama MA Sisson DD Prosek R Bulmer BJ Luethy MW Fuentes VL 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2007,21(6):1272-1279
BACKGROUND: Dilated cardiomyopathy (DCM) is characterized by reduced systolic function, heightened sympathetic tone, and high morbidity and mortality. Little is known regarding the safety and efficacy of beta-blocker treatment in dogs with DCM. HYPOTHESIS: Carvedilol improves echocardiographic and neurohormonal variables in dogs with DCM over a 4-month treatment period. METHODS: Prospective, placebo-controlled, double-blinded randomized study. Dogs with DCM underwent echocardiography, ECG, thoracic radiographs, and neurohormonal profiling, followed by titration onto carvedilol (0.3 mg/kg q12h) or placebo over a 4-week period and subsequently received 3 months of therapy. Primary study endpoints included left ventricular volume and function. RESULTS: Sixteen dogs received carvedilol and 7 received placebo. At study end, 13 carvedilol dogs and 5 placebo dogs were alive. There was no difference in the mean percentage change in left ventricular volume at end-diastole (LVVd), left ventricular end-systolic volume (LVVs), and ejection fraction (EF) between treatment groups, suggesting that both groups experienced similar amounts of disease progression. Carvedilol treatment did not result in significant changes in neurohormonal activation, radiographic heart size, heart rate, or owner perceived quality-of-life. Baseline B-type natriuretic peptide (BNP) predicted dogs in the carvedilol-treated group that maintained or improved their EF over the study duration. CONCLUSIONS AND CLINICAL IMPORTANCE: Carvedilol administration did not improve echocardiographic or neurohormonal indicators of heart function. The lack of effect may be related to severity of disease, carvedilol dose, or brevity of follow-up time. Statistical power of the present study was adversely affected by a high fatality rate in study dogs and small sample size. 相似文献
9.
10.
尽管我们已经充分了解了体重20千克以上仔猪的生长和营养之间的关系,但对于断奶后阶段仔猪的营养就了解甚少。最近的研究以及在猪场中的应用结果表明,应用更为准确的断奶饲料方案和特种过渡日粮就可使仔猪顺利生长,从而避免发生在许多猪场都可见到的活体增重下降。 相似文献