全文获取类型
收费全文 | 2823篇 |
免费 | 244篇 |
专业分类
林业 | 40篇 |
农学 | 24篇 |
基础科学 | 6篇 |
71篇 | |
综合类 | 24篇 |
农作物 | 48篇 |
水产渔业 | 33篇 |
畜牧兽医 | 2776篇 |
园艺 | 8篇 |
植物保护 | 37篇 |
出版年
2024年 | 2篇 |
2023年 | 53篇 |
2022年 | 8篇 |
2021年 | 8篇 |
2020年 | 97篇 |
2019年 | 7篇 |
2018年 | 74篇 |
2017年 | 73篇 |
2016年 | 55篇 |
2015年 | 81篇 |
2014年 | 116篇 |
2013年 | 137篇 |
2012年 | 104篇 |
2011年 | 125篇 |
2010年 | 95篇 |
2009年 | 100篇 |
2008年 | 88篇 |
2007年 | 68篇 |
2006年 | 52篇 |
2005年 | 41篇 |
2004年 | 75篇 |
2003年 | 71篇 |
2002年 | 77篇 |
2001年 | 74篇 |
2000年 | 64篇 |
1999年 | 76篇 |
1998年 | 106篇 |
1997年 | 101篇 |
1996年 | 80篇 |
1995年 | 79篇 |
1994年 | 73篇 |
1993年 | 90篇 |
1992年 | 107篇 |
1991年 | 84篇 |
1990年 | 93篇 |
1989年 | 80篇 |
1988年 | 69篇 |
1987年 | 76篇 |
1986年 | 35篇 |
1985年 | 50篇 |
1984年 | 34篇 |
1983年 | 51篇 |
1982年 | 20篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1975年 | 2篇 |
1967年 | 2篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1961年 | 1篇 |
排序方式: 共有3067条查询结果,搜索用时 15 毫秒
21.
KENNETH A. BRUECKER DVM MS HOWARD B. SEIM III DVM DiplomateACVS STEPHEN J. WITHROW DVM DiplomateACVS 《Veterinary surgery : VS》1989,18(3):197-203
Sixty-four dogs with caudal cervical spondylomyelopathy (CCSM) caused by chronic degenerative disc disease were treated with ventral decompression (n = 20), linear traction and interbody screw stabilization (n = 7), or linear traction and plastic plate stabilization (n = 37). Interbody screw stabilization was ineffective in treating CCSM because of an unacceptably high rate of implant failures. Ventral decompression or linear traction and plastic plate stabilization were effective in the treatment of most patients with mild to moderate neurologic deficits (neck pain, paraparesis, or ambulatory tetraparesis). Although these techniques were also used successfully in some patients with severe neurologic deficits (weakly ambulatory tetraparesis or nonambulatory tetraparesis), variable success rates and prolonged postoperative recovery periods were noted. 相似文献
22.
23.
William R. Widmer DVM MS William E. Blevins DVM MS Samuel Jakovljevic DVM MS Robert F. Teclaw DVM PhD Connie M. Han RVT Cheryl D. Hurd RVT 《Veterinary radiology & ultrasound》1992,33(6):327-333
In a blind clinical trial, adverse effects after iohexol and iopamidol myelography were evaluated in 151 dogs. Eighty-one dogs were given iohexol (240 mgI/ml) and 70 dogs were given iopamidol (200 mgI/ml) by pre-determined assignment. Each dog was evaluated postmyelographically for seizures, hyperthermia, prolonged recovery from anesthesia and intensification of pre-existing neural signs. Myelographic quality was evaluated with a subjective scoring method. In comparing iohexol and iopamidol groups, there was not a statistically significant difference in the incidence of adverse effects or in myelographic quality. Iopamidol and iohexol appeared to be equally efficacious for routine canine myelography. 相似文献
24.
WILLIAM B. THOMAS DVM DONALD C. SORJONEN DVM MS Diplomate ACVIM STEPHEN T. SIMPSON DVM MS Diplomate ACVIM 《Veterinary surgery : VS》1991,20(6):409-412
Twenty-eight surgical procedures were performed in 23 dogs with atlantoaxial subluxation. Dorsal stabilization in seven dogs resulted in two recoveries and five failures of fixation. Ventral decompression and stabilization in 18 dogs resulted in eight recoveries and four failures of fixation. Six dogs died or were euthanatized within 7 days of ventral stabilization. Using either technique, four of seven nonambulatory dogs recovered. 相似文献
25.
LARRY G. CARPENTER DVM DONALD L. PIERMATTEI DVM PhD Dipiomate ACVS MOWAFAK D. SALMAN BVMS PhD Dipiomate ACVPM E. CHRISTOPHER ORTON DVM PhD Dipiomate ACVS A. WENDELL NELSON DVM PhD Dipiomate ACVS DANIEL D. SMEAK DVM Dipiomate ACVS PAUL B. JENNINGS Jr. VMD MS Dipiomate ACVS ROBERT A. TAYLOR DVM MS Dipiomate ACVS 《Veterinary surgery : VS》1991,20(6):373-378
Cadavers were compared with live anesthetized dogs for their effectiveness as models for surgical training of veterinary medical students. One group of students was trained using cadavers, and a peer group was trained using live anesthetized dogs. Both groups then performed an intestinal anastomosis using a live subject. The time to completion of the procedure was recorded. The anastomoses and celiotomy closures were evaluated. Each anastomosis was isolated and pressure tested. Reviewers blindly scored each surgical team's performance based on actual inspection of the surgical site and on viewing videotapes of the procedure. The participants' attitudes toward the use of live animals in teaching and research were documented before and after training. No statistically significant differences could be detected between the two groups. The results suggest that some substitution of cadavers for live dogs in surgical training might be feasible. 相似文献
26.
A Comparison of Injectable Anesthetic Combinations in Horses 总被引:4,自引:0,他引:4
N. S. MATTHEWS DVM Diplomate ACVA S. M. HARTSFIELD DVM MS Diplomate ACVA J. L. CORNICK DVM MS J. D. WILLIAMS PhD A. BEASLEY AHT 《Veterinary surgery : VS》1991,20(4):268-273
Six combinations of injectable anesthetic agents were administered to six adult horses in a Latin square design. The drug combinations were xylazine-ketamine, xylazine-butorphanol-ketamine, xylazine-tiletamine-zolazepam, xylazine-butorphanol-tiletamine-zolazepam, detomidine-ketamine, and detomidine-butorphanol-ketamine. Measured variables were heart rate, respiratory rate, systolic blood pressure, arterial pH (pHa), PaCO2, PaO2, recumbency time, and number of attempts necessary to stand. Quality of induction and recovery, muscle relaxation, and response to stimulus were evaluated subjectively. The horses required significantly more attempts to stand after administration of xylazine-tiletamine-zolazepam, xylazine-butorphanol-tiletamine-zolazepam, and detomidine-ketamine than after xylazine-ketamine, xylazine-butorphanol-ketamine, or detomidine-butorphanol-ketamine. Mean recumbency times varied from 23.0 minutes with xylazine-ketamine to 41.3 minutes with xylazine-butorphanol-tiletamine-zolazepam. There were significant differences in mean heart rates at minute 15, mean respiratory rates at minutes 5, 10 and 15, and mean systolic blood pressures at minute 10 of anesthesia. There were no significant differences in pHa, PaCO2 or PaO2. 相似文献
27.
A.E. Wanger DVM MS W.W. Muir III DVM Phd R.M. Bednaraki DVM MS 《Journal of Veterinary Emergency and Critical Care》1991,1(1):14-18
The purpose of this study was to determine whether lingual vanous blood gas samples reflect arterial acid-base gas status in anethetized dogs. Heparinized blood samples were drawn simultaneously from the lingual vein and a peripheral artery in 50 anestheized dogs that were clinical surgical patients, as well as from four experimental dogs in which hemorrahaic shock was being studied. Blood pH, oxygen tension (PO2 ), and bicarbonate (HCO3- )) from the two sources in clinical patients showed significant liner correlation, although arterial PO2 )(PaO2 )) tended to be approximately 110mm Hg higher than lingual venous PO2 ). During hemorrahgic shock, however, PaO2 ) and PaCO2 ) were significantly different from lingual venous PO2 ) and PCO2 ), Lingula venous blood gas analysis may be useful in assessing acid-base and blood gas status in routline cases, but should not be relied upon in dogs with low cardiac output or poor perfusion. 相似文献
28.
Intraperitoneal Circulation and Drainage in the Dog 总被引:1,自引:0,他引:1
GISELLE HOSGOOD BVSc MS FACVSc S. KATHLEEN SALISBURY DVM MS DiplomateACVS H. DAN CANTWELL DVM MS DiplomateACVR DENNIS B. DENICOLA DVM PhD DiplomateACVP 《Veterinary surgery : VS》1989,18(4):261-268
The patterns of dispersion and drainage of a low viscosity, oil-based contrast medium within the peritoneal cavity were examined in 12 normal dogs. Intraperitoneal injection of contrast medium was cranial or caudal and drainage was by the sump-Penrose or open peritoneal method. Radiographs were made over a 96 hour period, before and after peritoneal drainage was established. Each dog was euthanatized and necropsied. The contrast medium was dispersed throughout the peritoneal cavity 15 to 30 minutes after cranial injection and 1 to 2 hours after caudal injection. Most of the contrast medium drained within 6 hours after open peritoneal drainage and within 24 to 48 hours after sump-Penrose drainage. At necropsy, there was complete encasement of all sump-Penrose drains and partial occlusion of all open peritoneal incisions by omentum adhered to the abdominal wound edges. Peritonitis was not grossly evident, but all dogs showed histologic evidence of an acute inflammatory reaction associated with the drain or wound edge. 相似文献
29.
Phillip F. Steyn BVSc MRCVS MS Gregory Ogilvie DVM 《Veterinary radiology & ultrasound》1995,36(2):160-163
Technetium-99m methoxy-isobutyl-isonitrile (sestamibi) is a radiophartnaceutical used for the evaluation of myocardial perfusion. Increased uptake of sestamibi has also been documented in tumors. The objective of this study was to document the extracardiac biodistribution of 99m Tc sestamibi in the normal dog. Nine normal beagles were given 0.35 mCi/kg 99m Tc sestamibi intravenously, and 60 second images were made of the entire body at 1 hour post injection. A defined distribution pattern was recognized, with good visualization of the heart, liver, gallbladder, small intestine, kidneys, urinary bladder, popliteal lymph nodes, parotid salivary glands and zygomatic salivary glands. Splenic uptake was not seen.
Target to background ratios were calculated for all the regions listed, using background regions-of-interest with the smallest coefficient of variance for the denominator. The mean, range and standard deviation of these ratios are given. 相似文献
Target to background ratios were calculated for all the regions listed, using background regions-of-interest with the smallest coefficient of variance for the denominator. The mean, range and standard deviation of these ratios are given. 相似文献
30.
Michael R. Metcalf DVM MS Lloyd P. Tate DVM Loouis C. Sellett MS 《Veterinary radiology & ultrasound》1989,30(2):80-87