全文获取类型
收费全文 | 318篇 |
免费 | 23篇 |
专业分类
林业 | 28篇 |
农学 | 4篇 |
基础科学 | 1篇 |
119篇 | |
综合类 | 14篇 |
农作物 | 16篇 |
水产渔业 | 13篇 |
畜牧兽医 | 122篇 |
园艺 | 14篇 |
植物保护 | 10篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 8篇 |
2020年 | 7篇 |
2019年 | 9篇 |
2018年 | 22篇 |
2017年 | 10篇 |
2016年 | 14篇 |
2015年 | 12篇 |
2014年 | 16篇 |
2013年 | 17篇 |
2012年 | 19篇 |
2011年 | 30篇 |
2010年 | 25篇 |
2009年 | 16篇 |
2008年 | 16篇 |
2007年 | 22篇 |
2006年 | 16篇 |
2005年 | 18篇 |
2004年 | 15篇 |
2003年 | 6篇 |
2002年 | 14篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1932年 | 1篇 |
排序方式: 共有341条查询结果,搜索用时 15 毫秒
1.
Impact of an experimental PRRSV and Streptococcus suis coinfection on the pharmacokinetics of ceftiofur hydrochloride after intramuscular injection in pigs 下载免费PDF全文
D. N. Day J. W. Sparks L. A. Karriker K. J. Stalder L. W. Wulf J. Zhang J. M. Kinyon M. L. Stock R. Gehring C. Wang J. Ellingson J. F. Coetzee 《Journal of veterinary pharmacology and therapeutics》2015,38(5):475-481
This study determined the impact of porcine reproductive and respiratory syndrome virus (PRRSV) and Streptococcus suis coinfection on the pharmacokinetic (PK) profile of ceftiofur hydrochloride in pigs after intramuscular (i.m.) injection. Eighteen clinically normal crossbred gilts were assigned by weight into a challenge group (10 pigs) and control group (eight pigs). Pigs in both groups received a single i.m. injection of ceftiofur hydrochloride (Excenel RTU Sterile Suspension; Zoetis) at a 5 mg/kg BW dose. Serial blood samples were collected to characterize the plasma concentration curve. After a 10 days drug washout period, the challenge group was inoculated with 2 mL of PRRSV isolate VR‐2385 (105.75 50% tissue culture infective doses per mL) intranasally and 8 days later inoculated S. suis. When clinical disease was evident, the second PK assessment began in both challenge and control groups. Coinfected pigs demonstrated lower values of AUC and CMAX, but higher values of Cl/F and Vz/F indicating drug kinetics were altered by infection. The data from this study have implications on ceftiofur treatment regimens in diseased pigs. 相似文献
2.
Matteo Pastorino Alessandro Fedeli Andrea Salvadè Samuel Poretti Manuela Maffongelli 《Wood material science & engineering》2015,10(1):75-85
AbstractNondestructive testing and evaluation techniques able to extract information about the internal structure of the samples under test are very important in the wood industry. Microwave imaging systems have been considered for a long time promising apparatuses for this task. In this framework, approaches exploiting the full scattering phenomena for creating images of the distributions of the dielectric properties of the targets have been developed in the last few years. In this paper, a prototype of microwave tomographic system is presented and several experimental validation confirming its suitability for the use in the wood and forest product industry are reported. 相似文献
3.
Isabel Guadano Procesi Azzurra Carnio Federica Berrilli Margherita Montalbano Di Filippo Alessia Scarito Cristina Amoruso Marco Barni Marco Ruffini Giulia Barlozzari Manuela Scarpulla Claudio De Liberato 《Zoonoses and public health》2022,69(1):46-54
Giardia duodenalis is the most common intestinal protozoan in humans and animals worldwide, including eight morphologically identical assemblages, infecting pets, livestock, wildlife and human beings. Assemblages A and B are those with the higher zoonotic potential, and they have been detected in several mammals other than humans; the others (C to H) show a higher host specificity. Cats can harbour both the specific Assemblage F and the zoonotic ones A and B. Several studies have been carried out on G. duodenalis genotypes in cats; however, the role of this species in the epidemiology of giardiasis is still poorly understood. In this scenario, the present study carried out the detection and genetic characterization at sub-assemblage level of G. duodenalis from colony stray cats in central Italy. In the period 2018–2019, 133 cat faecal samples were analysed for the presence of G. duodenalis cysts by a direct immunofluorescence assay. Positive samples were subsequently subjected to molecular analyses for assemblage/sub-assemblage identification. Forty-seven samples (35.3%) were positive for G. duodenalis cysts by immunofluorescence. G. duodenalis DNA was amplified at SSU-rDNA locus from 39 isolates: 37 were positive for zoonotic Assemblage A and 2 showed a mixed infection (A + B). Positive results for the β-giardin gene were achieved for 25 isolates. Sequence analysis revealed 16 isolates belonging to Sub-assemblage AII and 8 to Sub-assemblage AIII. One isolate resulted as ambiguous AI/AIII. Large sequence variability at the sub-assemblage level was detected, with several double peaks and mutations, making complex a proper isolate allocation. When compared with previous studies, the 35.3% prevalence of G. duodenalis in cats reported in the present article was surprisingly high. Moreover, all positive cats resulted to be infected with zoonotic assemblages/sub-assemblages, thus indicating stray cats as a possible source of human giardiasis and highlighting the sanitary relevance of cat colonies in the study area. 相似文献
4.
A GIS-based method for the reconstruction of the late eighteenth century forest vegetation in the Prignitz region (NE Germany) 总被引:1,自引:0,他引:1
Our goal was to reconstruct the late eighteenth century forest vegetation of the Prignitz region (NE Germany) at a scale of
1:50,000. We also wanted to relate the historical forest vegetation to the actual and potential natural vegetation. For these
purposes, we selected 15 woody species and transferred relevant data found in historical records from various sources together
with the recent localities of (very) old individuals belonging to these woody species into ArcView GIS. Following multi-step
data processing including the generation of a point density layer using a moving window with kernel estimation and derivation
of vegetation units applying Boolean algebra rules together with information on site conditions, we derived 17 forest communities
corresponding to the potential natural vegetation. We were able to reconstruct the historical forest vegetation for 90% of
the forest area ca. 1780. Only two of the 17 forest communities covered large parts of the forested area. The oak forest with
Agrostis capillaris covered about 44% of the total forest area, and alder forests on fenland made up about 37%. Oak-hornbeam forests with Stellaria holostea comprised slightly less than 6% of the forest area, while all other forest communities comprised less than 1%. The historical
forest vegetation is more similar to the potential forest vegetation and quite different from the actual forest vegetation
because coniferous tree species currently cover approximately two-thirds of the actual forest area. The most beneficial result
of this study is the map of high-resolution historical vegetation units that may serve as the basis for various further studies,
e.g., modelling long-term changes in biodiversity at the landscape scale. 相似文献
5.
Chemical composition and antimicrobial activity of Momordica charantia seed essential oil 总被引:1,自引:0,他引:1
The essential oil obtained from the seeds of Momordica charantia was analyzed by GC/MS. Twenty-five components, representing 90.9% of the oil, were identified. The main constituents were trans-nerolidol, apiole, cis-dihydrocarveol and germacrene D. Furthermore, the oil was tested for its antibacterial and antifungal activities. Staphylococcus aureus was found to be the most sensitive microorganism with MIC values <500 microg/ml. 相似文献
6.
Rauter AP Filipe MM Prata C Noronha JP Sampayo MA Justino J Bermejo J 《Fitoterapia》2005,76(5):433-438
Diacronema sp. was cultured and its sterols were separated by column chromatography on silica gel. The new sterol 24-ethyl-4alpha-methyl-cholestane-3,20-diol (1) was characterised by NMR and MS spectrometry, as well as (22E)-24-ethyl-4alpha-methyl-5alpha-cholest-22-en-3beta-ol (2) and beta-sitosterol, the major components of the sterol fractions. Neither the biosynthetic origin of the new dihydroxysterol nor its role in the biochemistry of Diacronema is known. 相似文献
7.
During the years 2008 to 2010 beetles of the genus Agriotes were monitored by means of pheromone traps in Rhineland-Palatinate. Each trap contained the female sexual pheromone of either Agriotes obscurus, A. sordidus, A. lineatus, A. sputator, or A. ustulatus. Beetles of these species could be caught, additionally also specimens of the species A. gallicus, A. acuminatus, and A. pilosellus. Specimens of A. brevis and A. proximus could not be caught, not even in traps with pheromones according to their species. The high frequency of A. sputator in the Upper Rhine Valley and mild river valleys was surprising. This might be an explanation for the increasing damages especially in potatoes during the past seven years. Also the species A. ustulatus occurred mainly in the Rhine Valley. The species A. obscurus was found predominantly in higher altitudes, A. lineatus and A. sputator appeared in the whole area, with varying frequencies. In all, we could determine the composition of Agriotes-species in 27 fields. In two fields traps were exposed in two subsequent years, in one field in three years. The changes in the populations are shown. The beetles collected in some fields were compared with the according wireworms. 相似文献
8.
A simple and sensitive liquid chromatography-mass spectrometry confirmatory method for analyzing sulfonamide antibacterials in milk and egg 总被引:1,自引:0,他引:1
Cavaliere C Curini R Di Corcia A Nazzari M Samperi R 《Journal of agricultural and food chemistry》2003,51(3):558-566
A simple and specific method able to identify and quantify traces of 14 sulfonamide antibacterials (SAs) in milk and eggs is presented. This method uses a single solid-phase extraction (SPE) cartridge for simultaneous extraction and purification of SAs in the above matrices. Milk and egg samples are passed through a Carbograph 4 sorption cartridge. After analyte desorption, an aliquot of the final extract is injected into a liquid chromatography-mass spectrometry (LC-MS) instrument equipped with an electrospray ion source (ESI) and a single quadrupole. MS data acquisition is performed in the positive-ion mode and by a time-scheduled multiple-ion selected ion monitoring program. Compared to two published methods, the present protocol extracted larger amounts of SAs from both milk and egg and decreased the analysis time by a factor of 3 with milk samples and by a factor of 2 with egg samples. Recovery of SAs in milk at the 5 ppb level ranged between 76 and 112% with relative standard deviations (RSDs) of 相似文献
9.
Moreira MM Carvalho AM Valente IM Goncalves LM Rodrigues JA Barros AA Guido LF 《Journal of agricultural and food chemistry》2011,59(14):7654-7658
This paper reports the development of a novel electrochemical assay for xanthohumol (XN) by square-wave adsorptive-stripping voltammetry (SWAdSV) with a hanging mercury drop electrode. The method showed good repeatability (CV < 2%) and linearity (between 10 and 250 μg L(-1)), as well as suitable limits of detection (2.6 μg L(-1)) and quantification (8.8 μg L(-1)). The method was applied for the quantification of this compound in spent hops, and the results obtained were compared with the HPLC-UV method. XN contents determined by the SWAdSV method were 16 ± 1 and 100 ± 4 μg L(-1) for aqueous and methanolic extracts, respectively. The developed new methodology considerably reduces the analysis time, approximately from 25 min (HPLC-UV method) to 7 min, enabling a high sample throughput. In addition, the detection and quantification limits were approximately 5-fold lower than those obtained with the chromatographic method. 相似文献
10.
de Brito ES de Araújo MC Alves RE Carkeet C Clevidence BA Novotny JA 《Journal of agricultural and food chemistry》2007,55(23):9389-9394
Many tropical fruits are rich in anthocyanins, though limited information is available about the characterization and quantification of these anthocyanins. The identification and quantification of anthocyanin pigments in four tropical fruits were determined by HPLC-MS/MS. Fruits studied included acerola (Malphigia emarginata), jussara (Euterpe edulis), jambol?o (Syzygium cumini), and guajiru (Chrysobalanus icaco). All four fruits were found to contain anthocyanin pigments. Anthocyanidin backbones included cyanidin, delphinidin, peonidin, pelargonidin, petunidin, and malvidin. Guajiru contained several acylated forms, while acerola, jussara, and jambol?o contained only nonacylated glycosides. These results demonstrate that these tropical fruits are rich in anthocyanins and that the anthocyanins are widely ranging in anthocyanidin backbone, glycosylation, and acylation. 相似文献