全文获取类型
收费全文 | 3235篇 |
免费 | 166篇 |
国内免费 | 2篇 |
专业分类
林业 | 96篇 |
农学 | 58篇 |
基础科学 | 12篇 |
282篇 | |
综合类 | 888篇 |
农作物 | 135篇 |
水产渔业 | 86篇 |
畜牧兽医 | 1704篇 |
园艺 | 38篇 |
植物保护 | 104篇 |
出版年
2021年 | 27篇 |
2020年 | 30篇 |
2019年 | 35篇 |
2018年 | 44篇 |
2017年 | 44篇 |
2016年 | 45篇 |
2015年 | 28篇 |
2014年 | 36篇 |
2013年 | 120篇 |
2012年 | 112篇 |
2011年 | 139篇 |
2010年 | 47篇 |
2009年 | 54篇 |
2008年 | 134篇 |
2007年 | 142篇 |
2006年 | 157篇 |
2005年 | 133篇 |
2004年 | 113篇 |
2003年 | 107篇 |
2002年 | 127篇 |
2001年 | 80篇 |
2000年 | 72篇 |
1999年 | 83篇 |
1998年 | 33篇 |
1997年 | 32篇 |
1996年 | 28篇 |
1995年 | 39篇 |
1994年 | 19篇 |
1992年 | 79篇 |
1991年 | 73篇 |
1990年 | 56篇 |
1989年 | 59篇 |
1988年 | 52篇 |
1987年 | 55篇 |
1986年 | 54篇 |
1985年 | 72篇 |
1984年 | 37篇 |
1983年 | 39篇 |
1982年 | 21篇 |
1980年 | 21篇 |
1979年 | 24篇 |
1976年 | 21篇 |
1974年 | 25篇 |
1973年 | 40篇 |
1972年 | 29篇 |
1971年 | 34篇 |
1970年 | 25篇 |
1969年 | 27篇 |
1967年 | 21篇 |
1966年 | 24篇 |
排序方式: 共有3403条查询结果,搜索用时 78 毫秒
91.
92.
93.
94.
G Migaki R L Font R M Sauer W Kaplan R L Miller 《Journal of the American Veterinary Medical Association》1982,181(8):794-797
A review of protothecosis in dogs revealed that this malady usually begins in the gastrointestinal tract and progresses to systemic involvement. Clinical signs generally include bloody diarrhea or blood-stained feces as well as blindness, ataxia, and polyuria. Histologically, myriads of protothecal organisms in different stages of development are found in the granulomatous lesions. Two main species have been culturally identified: Prototheca zopfii and P wickerhamii. In the absence of cultural studies, species identification can be accomplished readily by immunofluorescence. The present case involved P zopfii infection in a 5-year-old female Cocker Spaniel that had bloody diarrhea, with a history of bloody diarrhea 6 months earlier. 相似文献
95.
The transmissible spongiform encephalopathies (TSEs) represent an emerging group of diseases that have been labeled as "prion diseases" because of the recent characterization of the infectious agent. TSEs are caused by prions, which induce neurodegenerative fatal diseases in humans and animals. Some TSEs (scrapie and kuru), have existed in both animals and humans for a very long time, whereas others such as bovine spongiform encephalopathy and variant Creutzfeld-Jakob disease have either recently emerged or are more thoroughly described and recognized. It is obvious that the medical community will be forced to consider these diseases in humans and animals for the future. This article offers a short review of the TSEs of immediate concern to zoo and wildlife veterinarians and wildlife biologists and suggests risk management strategies for the prevention of these diseases, with special focus on chronic wasting disease of cervids in North America. 相似文献
96.
Moore DA Atwill ER Kirk JH Brahmbhatt D Herrera Alonso L Hou L Singer MD Miller TD 《Journal of the American Veterinary Medical Association》2003,223(6):839-845
OBJECTIVE: To evaluate the effect of daily oral administration of decoquinate to neonatal calves experimentally challenged with various numbers of Cryptosporidium parvum oocysts. DESIGN: Clinical trial. ANIMALS: 75 calves. PROCEDURE: Calves were purchased from a commercial dairy during a 5-week period. Calves were housed in individual hutches and fed milk replacer with or without decoquinate (2 mg/kg [0.9 mg/lb per day]). Calves were randomly assigned to treatment and 1 of 5 challenge groups (0, 50, 100, 1000, or 10,000 C. parvum oocysts in 60 mL of saline [0.9% NaCl] solution administered p.o. on the day after arrival). Calves were maintained in the study for as long as 28 days. Calves were clinically assessed for diarrhea and dehydration. Fecal samples were submitted for oocyst enumeration 3 times each week. RESULTS: Treatment did not affect number of days to first watery feces (diarrhea), number of days to first oocyst shedding, or duration of diarrhea or oocyst shedding. Duration of oocyst shedding was significantly associated with challenge dose of oocysts administered to calves and number of days to first oocyst shedding. Duration of diarrhea and number of days to first oocyst shedding were significantly associated with week of arrival and number of days to first watery diarrhea. CONCLUSIONS AND CLINICAL RELEVANCE: Daily treatment with decoquinate at the dosage used in this study did not affect oocyst shedding or clinical signs associated with cryptosporidiosis. However, there was an indication that if the number of oocysts calves received could be reduced, then the duration of oocyst shedding and, hence, environmental loading of C. parvum oocysts could be reduced. 相似文献
97.
Tieghi C Miller WH Scott DW Pasquinelli G 《The Canadian veterinary journal. La revue veterinaire canadienne》2003,44(2):132-136
Medullary trichomalacia is the name proposed for a hair shaft abnormality that was recognized in 6 German shepherd dogs. Affected dogs had multifocal areas of broken hairs, especially on the dorsolateral trunk. Microscopic examination of hair shafts revealed focal areas of loss of architecture, swelling, and apparent softening of the medulla, followed by longitudinal (length-wise) splitting and breakage of the hair shaft. No cause could be found. Affected dogs were otherwise healthy, and apparent spontaneous recovery was the usual outcome. Relapses may occur. 相似文献
98.
99.
Michau TM Gilger BC Maggio F Davidson MG 《Journal of the American Veterinary Medical Association》2003,222(5):607-612
OBJECTIVE: To evaluate the outcome of thermokeratoplasty for treatment of ulcerative keratitis and bullous keratopathy secondary to corneal endothelial disease in dogs. DESIGN: Retrospective study. ANIMALS: 13 dogs. PROCEDURES: Medical records from 1994 to 2001 for dogs evaluated because of ulcerative keratitis and bullous keratopathy and treated with thermokeratoplasty were reviewed. RESULTS: There were 7 spayed females, 5 castrated males, and 1 sexually intact male, ranging from 6 to 16 years of age. Ten dogs had endothelial degeneration, and 3 dogs had breed-related endothelial dystrophy. All dogs had bullous keratopathy, characterized by microbullae formation that was detected via biomicroscopy. Recurrent or nonhealing corneal ulcers were detected unilaterally in 5 dogs and bilaterally in 8 dogs. Mean +/- SD duration from thermokeratoplasty until ulcerations were healed for all dogs was 2.2 +/- 1.1 weeks. All dogs that underwent thermokeratoplasty for nonhealing corneal ulceration secondary to endothelial disease and corneal edema had epithelial wound healing and resolution of corneal ulceration. Mean duration of treatment (ie, topical treatment required until resolution of ulceration) was significantly less after thermokeratoplasty than duration of treatment (with multiple treatments) prior to referral. CONCLUSIONS AND CLINICAL RELEVANCE: It may be necessary to perform thermokeratoplasty of the entire cornea to prevent recurrence of ulcerations in areas that have not been treated with thermokeratoplasty. 相似文献
100.
Accelerated chilling of carcasses to improve pork quality 总被引:8,自引:0,他引:8
Our objectives were to determine the optimal accelerated chill time immediately postmortem necessary to improve the quality of pork muscle and to decrease the incidence of pale, soft, and exudative pork. Carcasses from 81 market hogs were cooled either by conventional chill (CC) at 2 degrees C or by accelerated chill (AC) at -32 degrees C for 60, 90, 120, or 150 min, and then placed into a 2 degrees C cooler for the remainder of the 24-h chill period. Loin muscle pH was higher (P < 0.05) for the carcasses that were accelerated chilled longer than 60 min. Although loin visual color, texture, and firmness scores increased (P < 0.05) with AC time, no improvements were noted beyond 60 min. Color, pH, texture, firmness, and CIE L*a*b* values of fresh ham muscles were not (P > 0.05) affected by AC. In addition, AC did not (P > 0.05) affect purge, drip, or thaw loss of fresh products, sensory scores of loins or processed hams (except initial juiciness; P < 0.05), water-holding capacity of processed hams, or processing characteristics of hams. Cooking loss and Warner-Bratzler shear values for hams and loins were not (P > 0.05) affected by AC. Accelerated chilling caused loins to be darker (lower L* value; P < 0.05) and to have lower (P < 0.05) b* values (less yellow) than CC loins. Accelerated chilling increased water-holding capacity in fresh hams, bound water being the greatest (P < 0.05) in the 120- and 150-min AC groups. These results demonstrate that improvements in pork loin quality can be made using freezer-accelerated chilling for carcasses. 相似文献