全文获取类型
收费全文 | 394篇 |
免费 | 23篇 |
专业分类
林业 | 26篇 |
农学 | 7篇 |
5篇 | |
综合类 | 10篇 |
农作物 | 6篇 |
水产渔业 | 6篇 |
畜牧兽医 | 349篇 |
植物保护 | 8篇 |
出版年
2020年 | 7篇 |
2018年 | 10篇 |
2017年 | 6篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 16篇 |
2013年 | 9篇 |
2012年 | 10篇 |
2011年 | 19篇 |
2010年 | 15篇 |
2009年 | 33篇 |
2008年 | 11篇 |
2007年 | 11篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 8篇 |
2003年 | 6篇 |
2002年 | 16篇 |
2001年 | 16篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 20篇 |
1997年 | 14篇 |
1996年 | 16篇 |
1995年 | 9篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 20篇 |
1989年 | 13篇 |
1988年 | 5篇 |
1987年 | 11篇 |
1986年 | 7篇 |
1985年 | 3篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1977年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1963年 | 1篇 |
1962年 | 1篇 |
1959年 | 1篇 |
1956年 | 1篇 |
1954年 | 2篇 |
1953年 | 2篇 |
1950年 | 1篇 |
排序方式: 共有417条查询结果,搜索用时 46 毫秒
11.
Debra K. Baird DVM John T. Hathcock DVM MS Steven A. Kincaid DVM MS PhD Paul F. Rumph DVM MS John Kammermann MS William R. Widmer DVM MS Denise Visco PhD Donald Sweet MD 《Veterinary radiology & ultrasound》1998,39(3):167-173
Six healthy adult male mongrel dogs underwent cranial cruciate ligament transection in the left stifle. Survey radiography of both stifles and low-field (0.064 T) MRI of the left stifle were performed preoperatively and at 2, 6, and 12 weeks postoperatively. Focal changes in signal intensity were seen with MRI in the subchondral bone of the medial tibial condyle at 2 and 6 weeks postoperatively. At 12 weeks postoperative, a cyst-like lesion was detected using MRI in the subchondral bone of the medial tibial condyle in 4 of 6 dogs and a less defined lesion at this site in the remaining 2 dogs. The cyst-like lesion was spherical in shape and showed typical characteristics of fluid with low signal intensity on T1-weighted images, high signal intensity on T2-weighted images and high signal intensity on inversion recovery images. The lesion was seen in the subchondral bone of the caudal medial and/or middle region of the tibial plateau slightly cranial to the insertion of the caudal cruciate ligament. No subchondral cysts were seen in the tibia on radiographs. Histopathologically, the tibia was characterized by a loose myxomatous phase of early subchondral cyst formation. 相似文献
12.
Piper L. Wall DVM PhD † Akella Chendrasekhar MD †Gregory A. Timberlake MD † 《Journal of Veterinary Emergency and Critical Care》1998,8(2):109-115
The accuracy and precision of an end-tidal infrared CO2 monitor and customized capnography tubing system designed to measure gastrointestinal intraluminal CO2 partial pressure (Pi CO2 ) were tested in vitro. Samples were taken from the customized capnography tubing placed in either 5% or 10% CO2 gas at discrete intervals ranging from one minute to twelve minutes. For a given time interval, the tubing PCO2 measurement was a constant fraction of the actual PCO2 (all standard errors < 0.02). For increasing time intervals, the ratio of the tubing PCO2 to actual PCO2 increased logarithmically. In the 5% and 10% CO2 , the regression coefficients were 0.89 and 0.85 for 8 French tubing and 0.99 and 0.91 for 6 French tubing. Beacuase of its accuracy and precision, this system may provide automated gastrointestinal CO2 partial pressure monitoring at short intervals (e.g. 5 minutes), facilitating testing of the role of gastrointestinal Pi CO2 information in treatment algorithms. (Vet Emerg & Crit Care, 1998; 8: 109–116) 相似文献
13.
Angular deformities of 25 or 37 degrees valgus were created by transverse wedge osteotomies in the diaphysis of the radius in 3-month-old Cocker Spaniels. Spontaneous correction was judged from radiographs until skeletal maturity. The magnitude of correction was estimated, using the opposite normal leg as a control. Asymmetrical physeal growth corrected the induced angulation between the proximal and distal radial joint plane surfaces (joint plane angle). The average correction of the joint plane angle was 80% in the 25 degree group, and 72% in the 37 degree group. Bone remodeling of the radial shaft corrected the induced diaphyseal angulation by 50% in both groups during the study. 相似文献
14.
15.
Grady H. Shelton DVM Chris K. Grant PhD DSc Michael L. Linenberger MD Janis L. Abkowitz MD 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1990,4(6):317-319
Griseofulvin administration was associated with the development of absolute neutropenia in six of seven (86%) cats with feline immunodeficiency virus (FIV) infection. The neutropenia was severe (less than 400 neutrophils/microliter) in four of the six affected cats, and one cat died from sepsis. Neutrophil counts returned to baseline values within 15 days after drug withdrawal in all surviving cats. No symptoms or hematologic abnormalities were observed in four normal (FIV-seronegative) cats treated with the same lot of griseofulvin at equivalent doses. Neutropenia recurred in two of two FIV-seropositive cats upon griseofulvin rechallenge. Cats with FIV infections appear to be at increased risk for griseofulvin-associated neutropenia. This phenomenon may be analogous to the increased frequency of antibiotic-induced neutropenias observed in humans infected with the human immunodeficiency virus. 相似文献
16.
ALAN B. KUZMA BSc DVM DVSc DAVID L. HOLMBERG DVM MVSc DiplomateACVS CRAIG W. MILLER DVM MSc DiplomateACVS IAN BARKER DVM MSc PhD JAMES ROTH MD FRCS 《Veterinary surgery : VS》1990,18(6):439-445
An orthotopic colon graft based on the middle colic artery and vein was implanted with microvascular technique and a stapling instrument in five dogs. The grafts were successful in four dogs. A similar colon autograft was used to replace the entire thoracic esophagus in five dogs. The recipient vessels were the left carotid artery and left external jugular vein. Four of the grafts failed because of kinking and thrombosis of the arterial supply (2 dogs) or the venous outflow (2 dogs). One graft, which had a viable vascular supply, developed a severe leak at the colon-to-stomach anastomosis, and the dog was euthanatized on day 3. The recipient vascular pedicle was modified and used successfully to replace a portion of the cervical esophagus in three dogs. The grafts survived, the dogs could swallow liquids and semisolid food well, and, at necropsy after 4 weeks, the anastomotic sites were well healed. The graft sites contained essentially normal colon mucosa. 相似文献
17.
The phenology and frost hardiness of shoots of 15 provenancesof Alnus rubra growing in Scotland were measured over one autumn,winter and spring. Dates of budset (in September) and the onsetof rapid frost hardening (in October-November) occurred about2 days earlier for each degree latitude of origin northwards,except for an Idaho provenance. However, all provenances dehardenedat about the same time in March and burst their buds between8 and 14 April. Assuming that rapid frost hardening in the autumnwas triggered primarily by shortening daylengths, Alaskan provenancesof A. rubra seemed better adapted to British conditions thansouthern British Columbian provenances, which have been mostcommonly planted. However, even Alaskan provenances are proneto spring frost damage. Scottish A. glutinosa and Alaskan A.sinuata set buds and frost hardened 12 weeks before eventhe Alaskan A. rubra, and burst their buds 23 weeks laterin April-May. All three species were hardy to below 30°Cfrom December to mid-March. 相似文献
18.
Autumn Frost Damage on Young Picea sitchensis 2. Shoot Frost Hardening, and the Probability of Frost Damage in Scotland 总被引:3,自引:0,他引:3
The natural increase in frost hardiness of detached shoots ofPicea sltchensis during August to November was measured usinga programmable freezing chamber. Oregon, Queen Charlotte Islandsand Alaskan provenances were compared, and the effects on hardeningof long days, warm temperatures and frosts were determined.A computer model was constructed to mimic the observed patternsof autumn frost hardening, as functions of air minimum temperatures,daylengths and the occurrence of frosts. The model was used(a) to describe the pattern of autumn frost hardening at differentsites in northern Britain, using past meteorological records,and hence (b) to determine when frosts occurred that might havedamaged young trees. The model accurately predicted known instancesof autumn frost damage at Kirroughtree and Carnwath. The predicted probability of autumn frost damage on young treesof P. sitchensis in upland areas of Scotland was much lowerthan that previously predicted for spring frost damage. Theestimated return time for autumn frost damage to an Oregon provenanceat Eskdalemuir was 8.3 years, and the return time for a Q.C.I.provenance was longer than 10 years. Most damaging frosts occurredin October, but frosts like those on 1315 October 1971,which followed warm weather and caused wide spread damage inScotland, have been quite rare. Alaskan provenances would rarelybe damaged by autumn frosts, nor would trees of Q.C.I. provenancegrowing in lowland areas of Scotland, or at Masset on the QueenCharlotte Islands. 相似文献
19.