全文获取类型
收费全文 | 94082篇 |
免费 | 5091篇 |
国内免费 | 64篇 |
专业分类
林业 | 4146篇 |
农学 | 3042篇 |
基础科学 | 456篇 |
10976篇 | |
综合类 | 17261篇 |
农作物 | 3298篇 |
水产渔业 | 4721篇 |
畜牧兽医 | 48551篇 |
园艺 | 1077篇 |
植物保护 | 5709篇 |
出版年
2019年 | 810篇 |
2018年 | 1376篇 |
2017年 | 1477篇 |
2016年 | 1333篇 |
2015年 | 1154篇 |
2014年 | 1417篇 |
2013年 | 3297篇 |
2012年 | 2640篇 |
2011年 | 3130篇 |
2010年 | 2085篇 |
2009年 | 2105篇 |
2008年 | 3088篇 |
2007年 | 3030篇 |
2006年 | 2845篇 |
2005年 | 2657篇 |
2004年 | 2584篇 |
2003年 | 2579篇 |
2002年 | 2333篇 |
2001年 | 3223篇 |
2000年 | 3220篇 |
1999年 | 2533篇 |
1998年 | 965篇 |
1997年 | 923篇 |
1996年 | 870篇 |
1995年 | 1065篇 |
1994年 | 944篇 |
1993年 | 886篇 |
1992年 | 1953篇 |
1991年 | 2009篇 |
1990年 | 1953篇 |
1989年 | 1883篇 |
1988年 | 1789篇 |
1987年 | 1845篇 |
1986年 | 1782篇 |
1985年 | 1754篇 |
1984年 | 1431篇 |
1983年 | 1265篇 |
1982年 | 821篇 |
1979年 | 1211篇 |
1978年 | 996篇 |
1977年 | 863篇 |
1976年 | 827篇 |
1975年 | 912篇 |
1974年 | 1164篇 |
1973年 | 1055篇 |
1972年 | 1137篇 |
1971年 | 1056篇 |
1970年 | 961篇 |
1969年 | 1004篇 |
1967年 | 844篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
991.
992.
993.
ABSTRACT1. The objectives of the current study were to investigate the mitochondrial genome and molecular phylogeny of Lueyang black-bone chicken, and provide molecule base to preserve and explore the specific chicken strain.2. Based on sequencing and clustering, the complete mitochondrial DNA map and sequences of Lueyang black-bone chicken were revealed, and two phylogenetic trees of Lueyang black-bone chickens based on D-loop sequences and the mitochondrial genome were constructed.3. The results showed that the complete mitochondrial genome of Lueyang black-bone chickens is 16,784bp in size, consisting of 22 transfer RNA genes, two ribosomal RNA genes, 13 protein-coding genes, and one non-coding control region. The base composition of the complete mtDNA sequence is 30.28% for A, 23.78% for T, 32.42% for C, 13.52% for G. Additionally, 10 haplotypes of D-loop sequences in 32 Lueyang black-bone chickens were detected, which were distributed into 4 clades (A, B, C and E).4. It was concluded that genetic diversity is wide in Lueyang black-bone chickens, and this strain has multiple maternal origins from different regions in China and neighbouring regions. 相似文献
994.
Comparison of the pharmacokinetic profiles of two different amphotericin B formulations in healthy dogs
下载免费PDF全文
![点击此处可从《Journal of veterinary pharmacology and therapeutics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
This study was conducted to compare the pharmacokinetic profiles of conventional (Fungizone®) and liposomal amphotericin B (AmBisome®) formulations in order to predict their therapeutic properties, and evaluate their potential differences in veterinary treatment. For this purpose, twelve healthy mixed breed dogs received both drugs at a dose of 0.6 mg/kg by intravenous infusion over a 4‐min period in a total volume of 40 ml. Blood samples were collected at 0, 0.5, 1, 1.5, 2, 3, 4, 8, 12, 24, 48, 72 and 96 hr after dosing, and concentrations of drug in plasma were determined by high‐performance liquid chromatography (HPLC). Pharmacokinetics was described by a two‐compartment model. Although both formulations were administered at the same doses (0.6 mg/kg), the plasma pharmacokinetics of liposomal amphotericin B differed significantly from those of amphotericin B deoxycholate in healthy dogs (p < .05). Liposomal amphotericin B showed markedly higher peak plasma concentrations (approximately ninefold greater) and higher area under the plasma concentration curve values (approximately 14‐fold higher) compared to conventional formulation. It is concluded that AmBisome® reached higher plasma concentration and lower distribution volume and had a longer half‐life compared to Fungizone®, and therefore, AmBisome® is reported to be an appropriate and effective choice for the treatment of systemic mycotic infections in dogs. 相似文献
995.
M. L. Stock S. T. Elazab W. H. Hsu 《Journal of veterinary pharmacology and therapeutics》2018,41(2):184-194
Triazines are relatively new antiprotozoal drugs that have successfully controlled coccidiosis and equine protozoal myeloencephalitis. These drugs have favorably treated other protozoal diseases such as neosporosis and toxoplasmosis. In this article, we discuss the pharmacological characteristics of five triazines, toltrazuril, ponazuril, clazuril, diclazuril, and nitromezuril which are used in veterinary medicine to control protozoal diseases which include coccidiosis, equine protozoal myeloencephalitis, neosporosis, and toxoplasmosis. 相似文献
996.
Li F. K. Yang Y. Jenna K. Xia C. H. Lv S. J. Wei W. H. 《Tropical animal health and production》2018,50(8):1893-1901
Tropical Animal Health and Production - This study was conducted to investigate the effects of heat stress on the behavioral and physiological patterns in Small-tail Han sheep housed indoors in... 相似文献
997.
Silva D. C. Queiroz P. J. B. Caetano D. B. S Assis B. M. Rabelo R. E. Silva L. A. F. 《Tropical animal health and production》2018,50(7):1631-1636
Tropical Animal Health and Production - We aimed to follow the epidemiologic evolution of bovine digital dermatitis (BDD) and other podal diseases grouped in a dairy farm in Central Brazil between... 相似文献
998.
999.
B. Poźniak K. Motykiewicz‐Pers T. Grabowski M. Świtała 《Journal of veterinary pharmacology and therapeutics》2018,41(1):163-165
The aim of this study was to assess the influence of growth on the pharmacokinetics of sodium salicylate (SS) in male turkeys. SS was administered intravenously at a dose of 50 mg/kg. Plasma drug concentrations were assessed by high‐performance liquid chromatography, and pharmacokinetic parameters were calculated by noncompartmental analysis. As the age increased from 6 to 13 weeks (body weight increase from 2.35 to 9.43 kg), median body clearance decreased from 1.34 to 0.87 ml/min/kg. This caused a significant increase in the median mean residence time from 3.42 to 4.44 hr. Elimination phase proved to be biphasic and two elimination half‐lives (T1/2el) were distinguished. Whereas T1/2el1 was found to increase with age by 128%, T1/2el2 represented a later but faster and less age‐dependent phase of elimination (increase by 56% in the respective groups). Volume of distribution decreased with age. These effects may lead to different therapeutic response to SS in turkeys of different age and body weights. 相似文献
1000.
A comparative study between responses of isolated bovine and equine digital arteries to vasoactive mediators
下载免费PDF全文
![点击此处可从《Journal of veterinary pharmacology and therapeutics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
C. Zizzadoro M. Caruso S. Punzi G. Crescenzo F. Zongoli C. Belloli 《Journal of veterinary pharmacology and therapeutics》2018,41(1):51-59
Hemodynamic perturbations, partly resulting from abnormal vasoconstriction of digital vessels, have been implicated in the pathogenesis of bovine and equine laminitis. This study compared the responsiveness of isolated bovine (BDA) and equine (EDA) digital arteries to pharmacological agents that stimulate receptor systems involved in the regulation of normal vessel tone. The role of the endothelium and the short‐ and longer‐term effects of an experimentally induced endothelial damage were also evaluated. Species‐related differences were found in the vessel reactivity to all of the receptor agonists tested. In intact BDA, as compared to intact EDA, norepinephrine was a more effective vasoconstrictor, 5‐hydroxytryptamine a more effective but less potent vasoconstrictor, isoproterenol a less effective vasodilator and carbamylcholine a less potent vasodilator. In BDA, but not in EDA, the contractile responses to norepinephrine and 5‐hydroxytryptamine were enhanced immediately after endothelium removal. However, the contractile reactivity of denuded BDA returned to basal values following overnight incubation. The differences suggest species specificity for the pathophysiology of digital vasomotor tone and function in horses and cattle. 相似文献