全文获取类型
收费全文 | 315篇 |
免费 | 22篇 |
专业分类
林业 | 17篇 |
农学 | 3篇 |
3篇 | |
综合类 | 7篇 |
农作物 | 2篇 |
水产渔业 | 3篇 |
畜牧兽医 | 298篇 |
植物保护 | 4篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2020年 | 7篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 4篇 |
2015年 | 5篇 |
2014年 | 16篇 |
2013年 | 8篇 |
2012年 | 10篇 |
2011年 | 16篇 |
2010年 | 10篇 |
2009年 | 31篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 7篇 |
2003年 | 6篇 |
2002年 | 15篇 |
2001年 | 16篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 16篇 |
1997年 | 13篇 |
1996年 | 13篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 8篇 |
1992年 | 10篇 |
1991年 | 4篇 |
1990年 | 16篇 |
1989年 | 12篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1984年 | 7篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有337条查询结果,搜索用时 46 毫秒
101.
QUANTITATIVE METHODS FOR INDIRECT CT LYMPHOGRAPHY 总被引:1,自引:0,他引:1
Eerik R. Wisner DVM J. Anthony Seibert PhD Richard W. Katzberg MD 《Veterinary radiology & ultrasound》1998,39(2):110-116
In this investigation, we applied quantitative CT methods to characterize contrast enhanced lymph nodes opacified using iodinated contrast media for indirect CT lymphography. lodinated nanoparticles were injected into the buccal submucosa and SQ into the metatarsus and metacarpus of four normal swine (1.0–4.0 ml/site, 76 mg I/ml). Attenuation (HU), volume (cm3 ), iodine concentration (mg I/cm3 ), total iodine uptake (mg I), contrast-to-noise ratio (CNR), and percent injected dose (%ID) were estimated in opacified inguinal, cervical and parotid/mandibular lymph nodes using manual image segmentation techniques on 24 hour post-contrast CT images. Lymph node volumes estimated by multiple slice ROI analysis were compared with estimates obtained by post-excisional weight measurements. HU and iodine concentration increased 5–20 fold in opacified nodes (p < 0.01) and CNR increased more than four-fold (p < 0.001). %ID ranged between 3.5 and 11.9% and did not appear dose related. ROI estimated lymph node volumes approximated volumes calculated from weight measurements. (R2 = 0.94, p < 0.0001). We conclude that interstitially injected iodinated nanoparticles increase attenuation and conspicuity of targeted nodes on CT images. Quantitative methods could play an important clinical role in more accurate metastasis detection. 相似文献
102.
Gregory B. Daniel DVM MS Robert Denovo DVM MS A. Eric Schultze DVM PHD Dorothy Schmidt BS Gary T. Smith MD 《Veterinary radiology & ultrasound》1998,39(4):375-383
The extraction of the hepatobiliary radiopharmaceutical 99m Tc-mebrofenin ( Choletec ) by the liver can be used to evaluate the severity of hepatocellular disease. The hepatic parenchymal cells extract mebrofenin from the blood by the same active transport mechanism as bilirubin. The ability of the liver to extract 99m Tc-membrofenin is a measure of hepatic parenchymal cell function. In this study, we induced hepatocellular disease by administration of a hepatotoxic drug and compared a direct method of determining the hepatic extraction of 99m Tc-membrofenin to hepatic extraction fraction derived from deconvolutional analysis. We also compared both methods of calculating the hepatic extraction of 99m Tc-membrofenin to liver histopathology. Hepatic extraction fraction derived from deconvolutional analysis correlated very well to the direct measurement technique (R=0.922, p<0.001). Both methods of determining hepatic extraction correlated well to quantitative histopathology, having the same correlation coefficient and p values. (R=-0.833, p=0.003). As the hepatic extraction 99m Tc-membrofenin decreased, the severity of the histopathologic lesions of the liver increased in a linear fashion. There was a significant correlation of the hepatic excretion T1/2 to quantititative histopathology (R=0.949, p<0.001). The hepatic excretion T1/2 increased as the severity of the histopathologic lesions of the liver increased. Hepatic extraction (HEF) and excretion of 99m Tc-membrofenin are good predictors of the severity of hepatocellular damage in toxic induced liver disease. This study helps validate the premise that HEF derived from deconvolutional analysis ois a good predictor of the actual first pass hepatic extraction of 99m Tc-membrofenin. 相似文献
103.
PROBABLE TRIGEMINAL NERVE SCHWANNOMA IN A DOG 总被引:1,自引:0,他引:1
J.H. Saunders DVM L. Poncelet DVM DScV C. Clercx DVM PHD F.R. Snaps DVM DScV P. Flandroy MD P. Capasso MD R.F. Dondelinger MD 《Veterinary radiology & ultrasound》1998,39(6):539-542
A 7-year-old male Husky dog developed atrophy of the right masseter muscle and pruritis of the right side of the face. A myogenic origin was excluded using muscular biopsy. Electrophysiologically, there was involvement of the motor and sensory fibers of the trigeminal nerve, suggesting a lesion located between the brainstem and the trigeminal ganglion. On MRI examination, a nodular mass was detected in the right caudal fossa. This mass was characterized by intense enhancement after injection of contrast medium. Because of the progressive clinical signs, electrophysiology, and MRI results, a presumptive diagnosis of a trigeminal nerve schwannoma was made. The animal's condition improved slightly with corticosteroids. The dog underwent euthanasia 3 months after initial presentation. Necropsy was not performed. 相似文献
104.
NICOLE S. AMATO DVM ANDREW RICHARDS MD TREVOR A. KNIGHT BS DANIEL SPECTOR DVM RANDY J. BOUDRIEAU DVM Diplomate ACVS ECVS STEPHEN BELKOFF PhD 《Veterinary surgery : VS》2008,37(8):741-748
Objective— To compare the accuracy of reduction and the biomechanical characteristics of canine acetabular osteotomies stabilized with locking versus standard screws in a locking plate. Study Design— Ex vivo biomechanical study. Sample Population— Cadaveric canine hemipelves and corresponding femurs (n=10 paired). Methods— Transverse acetabular osteotomies stabilized with 5‐hole 2.4 mm uniLOCK® reconstruction plates using either 2.4 mm locking monocortical or standard bicortical screw fixation (Synthes® Maxillofacial). Fracture reduction was assessed directly (craniocaudal acetabular width measurements and gross observation) and indirectly (impression casts). All constructs were fatigue‐tested, followed by acute destructive testing. All outcome measures (mean±SD) were evaluated for significance (P<.05) using paired t‐tests. Results— Craniocaudal acetabular diameters before and after fixation were not significantly different (21.9±1.2 and 21.5±1.2 mm; P=.45). No significant differences were observed in acetabular width differences between pre‐ and postoperative fixation between groups (locking ?0.4±0.4 mm; standard ?0.4±0.3 mm; P=.76). Grossly, there was no significant difference in the repairs and impression casts did not reveal a significant (P=.75) difference in congruency between the groups. No significant differences were found in fracture gap between groups either dorsally (locking 0.38±0.23 mm versus standard 0.22±0.05 mm; P=.30) or ventrally (locking 0.80±0.79 mm versus standard 0.35±0.13 mm; P=.23), and maximum change in amplitude dorsally (locking 0.96±2.15 mm versus standard 0.92±0.89 mm; P=.96) or ventrally (locking 2.02±2.93 mm versus standard 0.15±0.81 mm; P=.25). There were no significant differences in stiffness (locking 241±46 N/mm versus standard 283±209 N/mm; P=.64) or load to failure (locking 1077±950 N versus standard 811±248 N; P=.49). Conclusion— No significant differences were found between pelves stabilized with locking monocortical screw fixation or standard bicortical screw fixation with respect to joint congruity, displacement of fracture gap after cyclic loading, construct stiffness, or ultimate load to failure. Clinical Relevance— There is no apparent advantage of locking plate fixation over standard plate fixation of 2‐piece ex vivo acetabular fractures using the 2.4 mm uniLOCK® reconstruction plate. 相似文献
105.
106.
ROBERT T. PERNELL DVM MS Diplomate ACVS JAMES L. MILTON DVM MS Diplomate ACVS ROBERT S. GROSS PhD RONALD D. MONTGOMERY DVM MS Diplomate ACVS JAMES G.W. WENZEL DVM PhD Diplomate ACT CARL G. SAVORY MD FACS HAROLD M. ABERMAN DVM MSE 《Veterinary surgery : VS》1995,24(4):337-346
Cementless femoral stems were placed into 12 normal greyhound femora. The implanted femora were divided into three groups by stem orientation and implant size and loaded in axial compression at a rate of 25 newtons (N) per second until failure. Rosette strain gauges were used to measure femoral principal strains at 500 N, 1,000 N, 1,500 N, and at maximum load. During maximum load, varus orientation of the femoral stem had significantly higher tensile hoop strains in the proximomedial cortex, whereas neutral orientation had higher tensile hoop strains along the cranial cortex. Femoral fractures occurred in these areas of peak tensile strain. There was no difference in maximum load between groups, therefore varus orientation did not predispose to fracture. Maximizing canal fill and implant fit increased implant stability. 相似文献
107.
108.
Philip D. Koblik DVM MA Chi-K Yen MD William J. Hornof DVM MS Pamela Whiting DVM Paul Fisher BS 《Veterinary radiology & ultrasound》1989,30(2):67-73
Transcolonic 123 I-Iodoamphetamine is rapidly absorbed across the colonic mucosa and binds to amine receptors in the liver and lungs. During the first ten minutes following colonic administration, a simple ratio of lung counts to lung counts plus liver counts provides an accurate estimate of the fraction of portal blood that bypasses hepatic sinusoids in dogs with portosystemic shunts. Studies were performed on 24 dogs with suspect portosystemic shunt. Shunt fraction values for 18 dogs with surgically confirmed portosystemic shunt were obviously higher than published values for normal dogs, and also significantly higher than values for the other six dogs, later confirmed to lack shunts. Postoperative studies were repeated on ten dogs with single shunt vessels 1–2 days after shunt closure. Total shunt ligation resulted in normal postoperative shunt fraction, whereas partial shunt ligation resulted in persistant elevation of shunt fraction. Transcolonic iodoamphetamine scintigraphy is noninvasive, easy to perform, and provides an accurate method to diagnose dogs with portosystemic shunt. 相似文献
109.
110.
P.J. Burns PhD M.J. Jawad MS J.M. Weld MVB MRCVS W.C. Kaufman DVM D.M. Witherspoon DVM PhD E.A. Wilson MD R.H. Douglas PhD 《Journal of Equine Veterinary Science》1984,4(5):202-208
Testicular diameters and monthly blood samples were obtained from 83 stallions aged 4 to 22 years that were maintained on Central Kentucky Thoroughbred stud farms. The effects of age, season, and exposure to increased photoperiod (16 hours light/day, December 15 to April 1) on testicular diameters and plasma concentrations of FSH, LH and testosterone were studied.The results indicated that Thoroughbred stallions show distinct seasonal and age related changes in most of the reproductive parameters studied and that exposure of such stallions to increased photoperiod produced significant alterations in these changes. Although lighting stimulated testicular growth and testosterone secretion early in the breeding season such changes were short lived. Lighted stallions appeared to become refractory to the lighting program since both testicular size and plasma testosterone concentrations were significantly reduced by June. 相似文献