全文获取类型
收费全文 | 555篇 |
免费 | 39篇 |
国内免费 | 1篇 |
专业分类
林业 | 8篇 |
农学 | 17篇 |
基础科学 | 4篇 |
46篇 | |
综合类 | 138篇 |
农作物 | 28篇 |
水产渔业 | 14篇 |
畜牧兽医 | 291篇 |
园艺 | 7篇 |
植物保护 | 42篇 |
出版年
2023年 | 4篇 |
2021年 | 6篇 |
2020年 | 12篇 |
2019年 | 19篇 |
2018年 | 8篇 |
2017年 | 18篇 |
2016年 | 11篇 |
2015年 | 16篇 |
2014年 | 16篇 |
2013年 | 17篇 |
2012年 | 34篇 |
2011年 | 32篇 |
2010年 | 15篇 |
2009年 | 14篇 |
2008年 | 35篇 |
2007年 | 22篇 |
2006年 | 26篇 |
2005年 | 15篇 |
2004年 | 24篇 |
2003年 | 32篇 |
2002年 | 24篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 8篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1991年 | 11篇 |
1990年 | 3篇 |
1989年 | 9篇 |
1987年 | 4篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1979年 | 4篇 |
1976年 | 6篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1972年 | 3篇 |
1970年 | 4篇 |
1969年 | 3篇 |
1967年 | 3篇 |
1900年 | 3篇 |
1899年 | 5篇 |
1898年 | 3篇 |
1892年 | 3篇 |
排序方式: 共有595条查询结果,搜索用时 15 毫秒
1.
Stanley O. Blois 《Water, air, and soil pollution》1977,7(2):147-164
Patterns of energy use in the U.S. by industry, commerce, residential and agriculture with comparisons of Northern and Central California energy use in the same sectors are presented. End-use applications are also covered. 相似文献
2.
3.
Results of grid keratotomy, superficial keratectomy and debridement for the management of persistent corneal erosions in 92 dogs 总被引:2,自引:0,他引:2
Ninety-two cases of persistent corneal erosions in dogs were analyzed for breed, gender, age and which eye was affected. The results of the treatment of 92 persistent corneal erosions in dogs by superficial keratectomy (SK), grid keratotomy (GK), or debridement with a sterile dry cotton swab are presented. These techniques gave better rates of healing than have been previously reported. All cases of persistent corneal erosions healed in this study. However, it must be noted that three cases treated with debridement only failed to heal after several treatments and were eventually treated with SK. After one procedure 80 out of 92 (87%) had healed. After one procedure, 63% of cases treated with debridement healed, 100% of cases treated with SK healed, and 85% of cases treated with GK healed. At the first postoperative visit, 88% (21/24 cases) of ulcers treated by SK had healed, and 75% (39/52 cases) of ulcers treated by GK had healed. Only 25% of the persistent corneal erosions had healed at the first visit after debridement. All 24 cases of persistent corneal erosions treated with SK healed after one treatment in a mean +/- SD of 9.3 +/- 3.9 days (median of 7 days). Fifty-two cases were managed with GK; 44 (83%) of these healed with one procedure and eight cases required a second GK procedure to resolve. A mean +/- SD of 13.4 +/- 5.1 days (median of 11.5 days) following GK was required for the persistent corneal erosions to heal. Nineteen cases were initially managed by debridement with a dry cotton swab under local anesthesia. Sixteen out of these 19 debridement cases healed (giving an overall healing rate of 84%) in a mean +/- SD time of 23.4 +/- 11.1 days (median 21.5). There were three cases that did not heal with debridement. These cases were debrided at 10-20 day intervals for 30-60 days, and were then treated with SK. Two of these cases healed within 7 days, the other case required 18 days to heal. Sixty-three per cent of persistent corneal erosions treated with debridement healed after one procedure; however, only four out of 19 cases (21%) were healed at the first revisit. Complications were rare: corneal edema occurred in two cases following multiple GK, and excessive granulation tissue in one case was managed with a SK. There was the occurrence of an ulcer adjacent to the surgery site in four cases, two cases following GK and two cases following SK. 相似文献
4.
Terry C. Gerros DVM MS John S. Mattoon DVM Stanley P. Snyder DVM PHD 《Veterinary radiology & ultrasound》1998,39(4):322-324
A 7-month-old La Mancha doe was presented with a right head tilt and ventral strabismus while circling to the left. History and physical examination led to a tentative diagnosis of a cerebral abscess. Computed tomography revealed a large, complex mass with ring enhancement in the left cerebral hemisphere, supporting the diagnosis. Postmortem examination confirmed the cerebral abscess. Bacterial cultures yielded heavy growth of Actinomyces pyogenes. 相似文献
5.
Tierney J Gowing H Van Sinderen D Flynn S Stanley L McHardy N Hallahan S Mulcahy G 《Veterinary parasitology》2004,122(3):171-182
The aim of this study was to determine the effects of indigenous chicken Lactobacillus species isolates from different parts of the gastrointestinal tract on Eimeria tenella invasion in vitro and to characterise the nature of inhibition, if any. The effects of competitive exclusion, steric interference and bacterial extracellular factors on E. tenella invasion were examined in an MDBK cell model. Several Lactobacillus species were initially isolated from chickens and identified by biochemical characteristics and 16S-rRNA. All Lactobacillus species isolates tested, significantly inhibited E. tenella invasion. Steric interference did not affect parasite invasion. Extracellular metabolic factors secreted by Lactobacillus species isolates into the surrounding media were shown to inhibit parasite invasion and these factors appeared to be heat stable. These results show that the natural microflora of poultry can provide a source of E. tenella-inhibiting Lactobacillus species in vitro, and thus may contribute to the control of Eimeria infection. 相似文献
6.
McCally RE Kim SE Bacon NJ Winter MD Cords AA Conway JA 《Journal of the American Animal Hospital Association》2012,48(3):198-202
A 2 yr old dog presented for dysphagia and coughing secondary to a 4 cm × 4 cm turgid subepiglottic mass. Cervical radiographs, an esophagram, and computed tomography confirmed the presence of a cystic mass that was not intimately associated with any surrounding structures. An incisional biopsy confirmed the cystic nature of the mass and helped to rule out a malignancy. A marginal surgical excision was performed via a ventral approach. Histopathology of the mass was consistent with a thyroglossal duct cyst. This is the first report of a thyroglossal duct cyst in this location in a dog. There was no recurrence of clinical signs 14 mo after surgery. 相似文献
7.
Olivry T Dunston SM Pluchino K Porter K Hammerberg B 《Veterinary immunology and immunopathology》2008,122(1-2):182-187
Human patients with atopic dermatitis (AD) commonly exhibit IgE reactivity to cutaneous self-antigens. The presence of serum IgE autoantibodies appears to correlate with disease severity, and it is suspected to reflect or contribute to tissue damage. The objective of this study was to determine whether IgE autoantibodies specific for cutaneous antigens could be detected in the serum of dogs with AD. Serum was collected from 19 dogs with untreated moderate to severe AD and four specific-pathogen free (SPF) dogs. Indirect immunofluorescence was performed using normal canine skin collected at four different locations (concave ear, nose, medial thigh and lateral thorax), while Western immunoblotting was done using normal canine ear pinna epidermal and dermal extracts and reducing conditions. In both methods, IgE was detected using a monoclonal antibody specific for heat stable epitopes of canine IgE. At 1:10 dilution, specific IgE autoantibodies against cutaneous autoantigens were not detected, with either method, in AD and SPF canine sera. Either IgE autoreactivity is not associated with moderate to severe AD in dogs, or the methods employed herein were not sensitive enough to permit IgE autoantibody detection. 相似文献
8.
9.
Eleven strains of the avian pathogen Mycoplasma synoviae were evaluated for the presence of sialidase activity with the use of the fluorogenic substrate 2'-(4-methylumbelliferyl)-alpha-D-N-acetylneuraminic acid and the sialidase inhibitor 2-deoxy-2,3- didehydro-N-acetylneuraminic acid. The kinetics of in vitro growth in modified Frey medium were also assessed for each strain. Five strains had been isolated from clinically symptomatic chickens, and strains WVU 1853T and K3344 have been demonstrated to be capable of reproducing disease in specific-pathogen-free chickens. All strains exhibited sialidase activity, although the amount varied 65-fold among strains (P < 0.0001) from 1.3 x 10(-7) to 2.0 x 10(-9) activity units per colony-forming unit. Strains originally isolated from clinically symptomatic birds had more (P < 0.05) sialidase activity than strains from asymptomatic birds. Strain WVU1853T exhibited the most sialidase activity (P < 0.0001) and grew to the highest culture density (P < 0.0001) among strains, but across strains, the rank correlation of growth rate with sialidase activity was not significant. Negligible activity was detected in conditioned culture supernatant fluid. This is the first report of sialidase activity in pathogenic strains of M. synoviae, which suggests a potential enzymatic basis for virulence of the organism. 相似文献
10.