全文获取类型
收费全文 | 276篇 |
免费 | 24篇 |
专业分类
林业 | 8篇 |
农学 | 3篇 |
基础科学 | 1篇 |
42篇 | |
综合类 | 58篇 |
农作物 | 5篇 |
水产渔业 | 32篇 |
畜牧兽医 | 140篇 |
园艺 | 1篇 |
植物保护 | 10篇 |
出版年
2021年 | 6篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 6篇 |
2016年 | 7篇 |
2015年 | 4篇 |
2014年 | 7篇 |
2013年 | 17篇 |
2012年 | 10篇 |
2011年 | 14篇 |
2010年 | 4篇 |
2007年 | 13篇 |
2006年 | 8篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2003年 | 8篇 |
2002年 | 10篇 |
2001年 | 11篇 |
2000年 | 8篇 |
1999年 | 3篇 |
1998年 | 10篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1986年 | 4篇 |
1984年 | 4篇 |
1982年 | 3篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 5篇 |
1970年 | 5篇 |
1969年 | 6篇 |
1968年 | 3篇 |
1967年 | 2篇 |
1960年 | 2篇 |
1948年 | 3篇 |
1931年 | 2篇 |
1912年 | 3篇 |
1910年 | 3篇 |
1893年 | 2篇 |
1885年 | 2篇 |
1884年 | 5篇 |
1883年 | 2篇 |
排序方式: 共有300条查询结果,搜索用时 265 毫秒
101.
Given the high unit value of live American lobsters (Homarus americanus), a non‐destructive field method to assess physiological state is desirable during out‐of‐water transport conditions. This study compared an Uricon® specific gravity refractometer, with a commercial veterinary blood analyser (Vet‐Test), as a method for determining the blood total protein concentration in live, out‐of‐water individuals. Regression analysis of R2 = 0.8641 (n = 64) was observed in determination of blood total protein concentration, y = 0.0036x + 1.0163 where x is the protein concentration in mg dL?1 in Vet‐Test. Our results (R2 = 0.864, SE ± 0.003) support the results (R2 = 0.985) of the previous study conducted by Leavitt & Bayer (1977 ) in which serum total protein was compared with the refractometric method. We therefore confirm that the refractometric method can be used as a reliable method to indicate health of a lobster by measuring the blood total protein concentration. The results show good correlation between the protein concentrations observed using the refractometric method and a Vet‐Test blood chemistry analyser. anova analysis was significant between the protein refractometer and the Vet‐Test (P < 0.05). Although protein concentration units obtained from both methods were different the results followed the same trends. Refractometry as a method is reliable to determine blood total protein concentrations in the American lobster. Consequently, a refractometric method can be used directly by commercial growers and distributors to assess responses to holding facility conditions and to feeding regimes. Whole blood protein concentrations may provide more information than serum protein concentrations as measured in the study of Leavitt & Bayer (1977 ). 相似文献
102.
103.
J. E. Rogers R. G. Riley S. W. Li M. L. O'Malley B. L. Thomas 《Water, air, and soil pollution》1985,24(4):443-454
The microbiological degradation of a mixture of alkylpyridines in groundwater maintained under aerobic and anaerobic conditions was examined. A marked difference was observed between the aerobic and anaerobic degradation rates. In the presence of a soil inoculum and under aerobic conditions, the residual alkylpyridine concentrations generally approached zero concentration within 10 to 31 days of incubation, whereas under anaerobic conditions the concentrations of residual alkylpyridines only decreased between 40 and 80% over a 33 day incubation period. Biodegradation rates under aerobic conditions were greatly affected by the specific ring substitution of structural isomers within a given weight class. A similar effect was not observed for anaerobic degradation rates. 相似文献
104.
105.
Caldwell LC Chase CC Riley DG Coleman SW Phillips WA Spicer LJ Welsh TH Randel RD 《Journal of animal science》2011,89(12):4017-4022
In an effort to determine whether tropical adaptation influences circulating concentrations of the growth-related hormone IGF-I, 3-breed diallel matings were conducted using temperate Bos taurus (Angus), tropical Bos indicus (Brahman), and tropical Bos taurus (Romosinuano). Purebred Angus, Braham, and Romosinuano and crossbred Angus-Braham, Angus-Romosinuano, and Braham-Romosinuano heifers and steers were evaluated in 2 separate calf crops from 2003 and 2004. Blood samples were obtained from 10 heifers of each breed group (n = 90) for each year at weaning and on d 0 and 84 of postweaning trials. Samples were also taken from 10 steers of each breed group (n = 90) at weaning and on d 0 and 60 of individual finishing phase feeding trials for each year. Concentrations of IGF-I were determined by RIA. Analyses included effects of sire breed, dam breed, year of record, the age of the dam of the calf in years, and interactions. Age of calf in days was investigated as a linear and quadratic covariate. Separate analyses were conducted for steers and heifers. The direct effect of Angus was to reduce (P < 0.03) heifer concentrations of IGF-I at d 84 and in the repeated measures analysis. In the repeated measures analysis, the direct effect of Romosinuano was to increase concentrations of IGF-I (P = 0.01). Relative to the temperate Bos taurus breed, plasma concentrations of IGF-I were numerically greater in male and female tropically adapted breed groups. 相似文献
106.
107.
Shipping suppresses lymphocyte blastogenic responses in Angus and Brahman X Angus feeder calves 总被引:1,自引:0,他引:1
An experiment using 40 Angus or Brahman X Angus preconditioned feeder calves was conducted to evaluate the influence of shipping on cellular immune reactivity. Steers were allotted on the basis of weight and breed to a control or shipped group. Shipped steers were trucked 700 km to a feedlot; control steers remained at the ranch of origin. Total and differential leukocyte counts, phytohemagglutinin skin-test responses, lymphocyte blastogenic responses, monocyte phagocytic function, packed cell volumes and concentrations of plasma cortisol were determined before, immediately after and 1 wk after shipment. At unloading, total leukocytes were increased (P less than .05) in shipped Angus steers. Shipped steers also had higher (P less than .01) numbers of neutrophils. Skin-test responses to phytohemagglutinin were higher (P less than .05) in Angus than in Brahman X Angus steers, but shipping did not influence the reaction. Lymphocyte blastogenic responses were lower (P less than .05) in shipped steers; however, cortisol levels in plasma were not elevated (P greater than .10) in shipped calves. Monocyte phagocytosis and packed cell volume were not influenced by shipping. These data suggest that shipped steers have suppressed lymphocyte blastogenic responses. 相似文献
108.
M K Andersen R A Field M L Riley R J McCormick G D Snowder D G Bailey 《Journal of animal science》1991,69(8):3284-3291
Sixty-four white-faced rams and wethers were dressed with the aid of a commercial pelt puller. The effects of age, castration, and season on difficulty of pelt removal and pelt damage were evaluated. Lambs were divided into two age groups (5 and 12 mo) within gender (ram and whether) and season (spring and fall). A greater force (P less than .05) was required to remove pelts from rams than from wethers in both 5- and 12-mo-old groups. Older lambs slaughtered in the fall required more force (P less than .05) to remove their pelts than did those slaughtered in the spring, but differences by season did not exist for 5-mo-old lambs. The difference between rams and wethers in percentage of live weight that was closely shorn pelt weight was not significant (P greater than .05). The area of grain crack in the flank expressed as a percentage of total area of the skin was lower (P less than .05) for skins from 5-mo-old lambs and ram lambs than it was for skins from 12-mo-old lambs and wether lambs, respectively. Factors involved in difficulty of pelt removal in ram lambs included crosscut shoulder weight, fat firmness, and carcass weight. Difficulty of pelt removal in wether lambs was best predicted by including crosscut shoulder weight and bodywall thickness in multiple regression equations. 相似文献
109.
R S Merkal A W Lepper A M Hintz J L Riley 《American journal of veterinary research》1977,38(1):113-116
Thermography of tuberculin skin reactions in cattle sensitized with Mycobacterium avium, Mycobacterium bovis, or Mycobacterium paratuberculosis was rapid and sensitive, but was not as specifically related to the homologous sensitization as was increased skin thickness at 48 and 72 hours. Systemic temperature responses were more completely monitored by radiotelemetry of intraperitoneally located temperature transmitters than by rectal thermometry, but the temperatures indicated by the 2 methods were nearly identical. The intraperitoneal transmitters showed that the systemic responses consisted of 1, 2, or 3 temperature peaks, and in 1 animal which had previously been exposed to a heterologous tuberculin, a hypothermic response developed. The systemic temperature responses were more specifically related to homologous sensitization than were dermal responses, but were more cumbersome to measure. 相似文献
110.
Qiu X Arthington JD Riley DG Chase CC Phillips WA Coleman SW Olson TA 《Journal of animal science》2007,85(10):2367-2374
The objective herein was to estimate heterosis and breed effects in purebred and crossbred Romosinuano, Brahman, and Angus calves on acute phase protein response to weaning and transportation. Calves (n = 1,032) were weaned in September of 2002, 2003, and 2004 at approximately 7 mo of age. Approximately 28 d after weaning, steer calves (n = 482) were transported 1,800 km (20 h) to Oklahoma. Concentrations of 3 acute phase proteins (ceruloplasmin, fibrinogen, and haptoglobin) were measured in blood samples. Calves (steers and heifers) were sampled at weaning, and 24 and 72 h postweaning. For separate analyses, steers sent to Oklahoma were sampled before shipment, upon arrival, and 24 and 72 h after arrival. Combinations of the following fixed effects were investigated: sire breed, dam breed, sampling time, birth location, calf sex (weaning only), year, cow age, and interactions. Effects of special interest were sire breed x dam breed as an indication of breed group of calf, and the interaction of sire and dam breeds with sampling time. Weaning age and BW were investigated as linear and quadratic covariates. Sire of calf within sire breed was a random term. The correlation structure of repeated measures was determined by comparison of information criterion values for different structures within each analysis. In general, plasma acute phase protein concentrations in weaned calves increased with sampling time. Concentrations in the transported steers increased through sampling at 24 h after arrival, and were lower at 72 h. Significant estimates of heterosis were detected for Brahman-Angus haptoglobin concentrations at weaning (0.38 +/- 0.14 mg/dL x 100; 44%), and for Romosinuano-Angus fibrinogen concentrations at weaning (11.4 +/- 5.5 mg/dL; 10%) and in transported steers (22.5 +/- 8.4 mg/dL; 20%). The direct effect of Romosinuano was to increase (P <0.004) ceruloplasmin concentrations of weaned calves (4.1 +/- 0.9 mg/dL) and of transported steers (3.9 +/- 1.3 mg/dL). The direct effect of Angus was to lower ceruloplasmin concentrations in weaned calves (-3.9 +/- 1.2; P = 0.001). Significant maternal effects were detected at weaning for ceruloplasmin concentrations in Romosinuano (-1.4 +/- 0.5 mg/ dL) and Angus (1.6 +/- 0.7 mg/dL) and fibrinogen concentrations in Brahman calves (-17.7 +/- 8.8 mg/dL). These data imply that acute phase protein concentrations in response to weaning and transportation are impacted by cattle breed. 相似文献