全文获取类型
收费全文 | 438篇 |
免费 | 19篇 |
专业分类
林业 | 97篇 |
农学 | 9篇 |
基础科学 | 1篇 |
64篇 | |
综合类 | 37篇 |
农作物 | 9篇 |
水产渔业 | 10篇 |
畜牧兽医 | 217篇 |
园艺 | 3篇 |
植物保护 | 10篇 |
出版年
2019年 | 5篇 |
2018年 | 7篇 |
2017年 | 4篇 |
2016年 | 8篇 |
2015年 | 4篇 |
2014年 | 9篇 |
2013年 | 24篇 |
2012年 | 13篇 |
2011年 | 22篇 |
2010年 | 10篇 |
2009年 | 8篇 |
2008年 | 17篇 |
2007年 | 22篇 |
2006年 | 11篇 |
2005年 | 15篇 |
2004年 | 27篇 |
2003年 | 17篇 |
2002年 | 17篇 |
2001年 | 11篇 |
2000年 | 9篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 9篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1983年 | 3篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1976年 | 3篇 |
1972年 | 4篇 |
1971年 | 11篇 |
1970年 | 6篇 |
1969年 | 4篇 |
1967年 | 4篇 |
1966年 | 4篇 |
1965年 | 6篇 |
1961年 | 3篇 |
1960年 | 4篇 |
1956年 | 3篇 |
1932年 | 4篇 |
1911年 | 6篇 |
排序方式: 共有457条查询结果,搜索用时 171 毫秒
71.
Anna Turska-Szewczuk Buko Lindner Iwona Komaniecka Alicja Kozinska Agnieszka Pekala Adam Choma Otto Holst 《Marine drugs》2013,11(4):1235-1255
Chemical analyses and mass spectrometry were used to study the structure of the lipopolysaccharide (LPS) isolated from Aeromonas bestiarum strain K296, serotype O18. ESI-MS revealed that the most abundant A. bestiarum LPS glycoforms have a hexa-acylated or tetra-acylated lipid A with conserved architecture of the backbone, consisting of a 1,4′-bisphosphorylated β-(1→6)-linked d-GlcN disaccharide with an AraN residue as a non-stoichiometric substituent and a core oligosaccharide composed of Kdo1Hep6Hex1HexN1P1. 1D and 2D NMR spectroscopy revealed that the O-specific polysaccharide (OPS) of A. bestiarum K296 consists of a branched tetrasaccharide repeating unit containing two 6-deoxy-l-talose (6dTalp), one Manp and one GalpNAc residues; thus, it is similar to that of the OPS of A. hydrophila AH-3 (serotype O34) in both the sugar composition and the glycosylation pattern. Moreover, 3-substituted 6dTalp was 2-O-acetylated and additional O-acetyl groups were identified at O-2 and O-4 (or O-3) positions of the terminal 6dTalp. Western blots with polyclonal rabbit sera showed that serotypes O18 and O34 share some epitopes in the LPS. The very weak reaction of the anti-O34 serum with the O-deacylated LPS of A. bestiarum K296 might have been due to the different O-acetylation pattern of the terminal 6dTalp. The latter suggestion was further confirmed by NMR. 相似文献
72.
Zimmerman KL Bender HS Boon GD Prater MR Thorn CE Prater D Robertson JL Saunders GK Sponenberg DP Inzana KD Lanz OI Wright E 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2000,29(1):29-34
Abstract: The cytologic and histologic features of 2 intracranial and 2 spinal (extramedullary cervical) canine meningiomas were compared. Cerebrospinal fluid analysis in 2 cases revealed mild, mixed cell pleocytosis, primarily composed of small lymphocytes and monocytoid cells, with a moderate increase in total protein concentration. Cytologic features suggestive of meningioma included cells with both epithelial and mes-enchymal characteristics and a tendency towards cell clustering. Tumor location also was useful in making a diagnosis. The 4 meningiomas differed histologically from one another, and included angioblastic, psam-momatous, meningotheliomatous, and microcystic anaplastic types, which conformed to a classification scheme for human meningiomas. The classification scheme could not be applied to cytologic specimens. 相似文献
73.
ABSTRACT Separate volume regression equations for pulpwood, sawtimber and over-mature Eucalyptus grandis are presented. An investigation of Schumacher and Hall's volume equation indicated that a better fit may be obtained by adding a constant to the dbh as predictor variable. The resultant equation is: log V = ?4,2328 + 1,7154 log (D-2) + 1,1070 log H. 相似文献
74.
Suzanne M. Donahue VMD DACVECC Cynthia M. Otto DVM PhD DAVECC 《Journal of Veterinary Emergency and Critical Care》2005,15(1):9-16
Objective: To describe the technique of thromboelastography (TEG) and review the applications of this coagulation test in humans and small animals. Data sources: Data sources included scientific reviews and original research publications. Human data synthesis: TEG in humans has been used for documentation of hypercoagulable and hypocoagulable states and has been shown to be beneficial in patient management. Veterinary data synthesis: Clinical evaluation of TEG in veterinary medicine is limited; however, recent reports have documented evidence of hypercoagulability in dogs with parvovirus and protein‐losing nephropathy. Additionally, many of the research models may be relevant to veterinary patients. Conclusions: TEG provides information about coagulation that is not available through routine coagulation tests. The application of TEG monitoring to veterinary patients shows promise; however, prospective clinical studies are needed. 相似文献
75.
C.A. Wiley M.C. Ottoson M.M. Garcia L.E. Wiley C.M. Otto 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2013,27(2):367-370
Background
Canine influenza virus (CIV) H3N8 infection is thought to be highly contagious and potentially deadly. Low seroprevalence in dogs participating in the sport of flyball in 2009 was reported. It remains unknown if prevalence is changing in dogs at risk.Objective
To determine seroprevalence of antibodies to CIV H3N8 in a population of pet dogs that participated in an indoor flyball tournament in Pennsylvania in November 2010.Animals
Dogs participating in a flyball tournament.Methods
Medical, travel, and activity histories for previous 10.5 months were obtained from consenting owners and serum samples were collected from dogs. Antibodies to CIV H3N8 were measured using hemagglutination inhibition.Results
Of 251 competing dogs, 103 dogs were tested. Overall, seroprevalence of CIV H3N8 in dogs participating in flyball was 1.9% (95% CI, 0.05–6.8%). Thirty‐five dogs were tested in both 2009 (all titers <8) and 2010 (all titers <8). Ten of 103 dogs had been vaccinated for CIV H3N8. Two dogs had positive titers (>8) and both had been vaccinated twice in the previous month. Titers in remaining 8 vaccinated dogs were undetectable. Seroprevalence in vaccinated dogs was 20% (95% CI, 5.7–50.1%), whereas in unvaccinated dogs it was 0% (95% CI, 0–4.0%). Although 7 dogs had history of respiratory signs, only 1, which was vaccinated, was serologically positive for CIV H3N8.Conclusions
Consistent with low prevalence of CIV H3N8 exposure previously reported in flyball dogs, unvaccinated dogs had 0% prevalence, suggesting a stable exposure rate. However, low seroprevalence may result in unprotected flyball dogs at risk for developing CIV H3N8. 相似文献76.
Falush D Wirth T Linz B Pritchard JK Stephens M Kidd M Blaser MJ Graham DY Vacher S Perez-Perez GI Yamaoka Y Mégraud F Otto K Reichard U Katzowitsch E Wang X Achtman M Suerbaum S 《Science (New York, N.Y.)》2003,299(5612):1582-1585
Helicobacter pylori, a chronic gastric pathogen of human beings, can be divided into seven populations and subpopulations with distinct geographical distributions. These modern populations derive their gene pools from ancestral populations that arose in Africa, Central Asia, and East Asia. Subsequent spread can be attributed to human migratory fluxes such as the prehistoric colonization of Polynesia and the Americas, the neolithic introduction of farming to Europe, the Bantu expansion within Africa, and the slave trade. 相似文献
77.
78.
OBJECTIVE: To determine if endoscopic-assisted foraminotomy significantly increased the area of the L7-S1 intervertebral foramen and if, over 12 weeks, stenosis would occur. STUDY DESIGN: Prospective, experimental study. ANIMAL POPULATION: Six clinically normal, 22-29 kg, adult dogs. METHODS: Using endoscopic assistance, unilateral L7-S1 foraminotomy was performed. Computed tomography of L7-S1 was performed preoperatively, immediately postoperatively, and at 12 weeks. Parasagittal foramen area (PFA) measurements were obtained at the entry, middle, and exit zones of the treated and control foramen for each period. Objective and subjective data were compared among dogs by time period and treatment status. RESULTS: Endoscopic-assisted foraminotomy resulted in a significant increase in the mean PFA of the entry and middle zones immediately postoperatively. The exit zone was not significantly larger at any time. The foramen remained significantly larger at 12 weeks only in the middle zone; however, some decrease in the surgically created foramen enlargement occurred at all 3 levels. The procedure was well tolerated but dogs did have transient, mild delay of functional return postoperatively. CONCLUSIONS: Endoscopic-assisted foraminotomy in dogs can be performed for certain foraminal regions, allowing enhanced visibility of the spinal canal. The foramen can be surgically enlarged at the entry and middle zones using this technique; however, some reduction of the foraminal enlargement occurs by 12 weeks. The clinical implications of this reduction cannot be determined from this study. CLINICAL RELEVANCE: Endoscopic-assisted foraminotomy could be used to improve intraoperative visualization in dogs with foraminal stenosis as a component of degenerative lumbosacral stenosis. 相似文献
79.
Otto Eichhorn 《Journal of pest science》1958,31(8):124-124
Ohne Zusammenfassung 相似文献
80.