首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   83篇
  免费   3篇
林业   1篇
农学   2篇
  9篇
综合类   5篇
水产渔业   10篇
畜牧兽医   55篇
园艺   4篇
  2023年   1篇
  2022年   2篇
  2021年   2篇
  2020年   1篇
  2018年   2篇
  2017年   2篇
  2015年   5篇
  2014年   3篇
  2013年   7篇
  2012年   5篇
  2011年   4篇
  2009年   3篇
  2008年   2篇
  2007年   6篇
  2006年   1篇
  2005年   6篇
  2004年   1篇
  2002年   1篇
  2001年   2篇
  1999年   2篇
  1998年   1篇
  1997年   3篇
  1996年   1篇
  1995年   1篇
  1993年   1篇
  1987年   1篇
  1985年   2篇
  1983年   1篇
  1982年   1篇
  1979年   3篇
  1978年   1篇
  1977年   2篇
  1975年   1篇
  1974年   1篇
  1973年   2篇
  1972年   1篇
  1971年   1篇
  1960年   1篇
  1949年   1篇
  1947年   1篇
  1903年   1篇
排序方式: 共有86条查询结果,搜索用时 15 毫秒
21.
An eight-year-old dog with a local relapse of an osteosarcoma was treated with partial maxillectomy and systemic radionuclide therapy that involved two injections, 43 and 45 megabec-querels per kg bodyweight of the bone-seeking agent samarium-153-ethylenediaminetetramethy-lene phosphonic acid (153Sm-EDTMP), 15 weeks apart. A transient drop in white blood cell count and platelet count was observed following each 153Sm-EDTMP treatment. Follow-up 21 months after surgery revealed no evidence of local recurrence or metastases. The dog was in excellent condition, suffering only minor sequelae from the surgical procedure. Compared with historical controls treated with surgery alone, the combination of surgery and systemic radionuclide therapy seems a promising strategy for the treatment of canine osteosarcoma.  相似文献   
22.
Four adult Norwegian Red cows were employed in an experiment designed to study the kinetics of lactose. The cows were given 50 g or 60 g of lactose by rapid intravenous injection of a 10 % lactose solution. Blood samples were taken at different intervals after injection, and lactose concentrations in the samples determined by an enzymatic/spectrophotometric method.The mean half-time for lactose elimination was 85.7 min, and for distribution 8.4 min. The mean apparent volume of distribution was calculated to be 0.189 1/kg, and total body clearance 1.55 ml min−1 kg−1.There was evidence to suggest that lactose mainly is eliminated renally from its distribution volume by glomerular filtration in the cow.  相似文献   
23.
In this study, we cryopreserved pig spermatozoa using carboxylated poly-L-lysine (CPLL) as the cryoprotectant to determine its efficacy. Pig spermatozoa were placed in a freezing extender containing 3% (v/v) glycerol and different CPLL concentrations. The motility indices of the spermatozoa cryopreserved with 0.25% (v/v) CPLL at 6 (59.3), 9 (53.7), and 12 (26.2) h after thawing were significantly higher (P < 0.01 or P < 0.05) than those of the spermatozoa cryopreserved without CPLL (53.7, 40.1, and 17.5 at 6, 9, and 12 h after thawing, respectively). The concentration of CPLL in the freezing extender did not affect the ability of frozen-thawed spermatozoa to fertilize oocytes in vitro. However, the blastocyst formation rate of embryos derived from spermatozoa cryopreserved with 0.25% CPLL (24.6%) was significantly higher (P < 0.01) than that of embryos derived from spermatozoa cryopreserved without CPLL (11.2%). The conception rate of the sows inseminated with spermatozoa cryopreserved with 0.25% CPLL (72.2%) was not significantly different from that of the sows inseminated with spermatozoa stored at 17°C (81.3%). However, the mean number of total piglets born to the former (10.0) was significantly lower (P < 0.05) than that of total piglets born to the latter (13.4). The results showed that CPLL in the freezing extender maintained the motility of frozen-thawed pig spermatozoa and improved the in vitro development of embryos produced by in vitro fertilization. In addition, we have demonstrated that piglets could be obtained with artificial insemination using spermatozoa cryopreserved with CPLL.  相似文献   
24.
An experiment was conducted in earthen ponds at the Asian Institute of Technology, Thailand to determine different phosphorus fertilizer dose effects on Nile tilapia production, water quality variables, nutrient utilization and cost‐benefit under supplemental feeding. Five phosphorus fertilization rates were used as treatments e.g. 100%, 75%, 50%, 25% and 0% of 7 kg P ha week?1. Nitrogen fertilization rate was fixed at 28 kg N ha week?1 for all the treatments. Sex‐reversed Nile tilapia were stocked at 3 fish m?2, and 30% CP floating feed fed at 50% satiation feeding rate. Nutrient budget showed higher phosphorus fertilizer input resulted in higher phosphorus sink in the sediment. Mean weight, mean weight gain, daily weight gain and net yield were not significantly different among treatments (P > 0.05). Total Kjeldahl nitrogen, total phosphorus and soluble reactive phosphorus were significantly different among treatments. Economic analysis showed phosphorus fertilization resulted in positive net returns. Though the gross income was not affected by different fertilization rates, significantly lowest cost was found in the treatment using 25% phosphorus fertilizer. It can be concluded from the research that 25% phosphorus fertilization might be used as an alternative strategy of Nile tilapia pond culture in terms of economic return and nutrient loss in sediment.  相似文献   
25.
The mollusc Pinctada margaritifera is the top economic aquaculture species in French Polynesia (export value) and forms the basis of the black pearl industry. Mass production of this unique gem, produced by a living organism, relies on a surgical operation requiring tissue from a donor pearl oyster to be grafted, together with a nucleus made of shell, into the gonad of a receiving pearl oyster. This technique is performed by expert grafters, whose work constitutes the first step influencing pearl farm production yield. This study makes the first report of effects mediated by individual grafters and by the season of grafting on three rates scored at 45 days post operation: nucleus retention, nucleus rejection and pearl oyster mortality. These results were obtained in a very large scale grafting experiment, designed and conducted in a single culture site in the atoll of Arutua (Tuamotu Archipelago) and involving a total of 52,910 grafts performed by ten professional grafters, during two contrasting seasons: autumn (four grafting experiments) and spring (three grafting experiments). Statistical analysis using linear mixed-effect model for both univariate and multivariate analysis was performed. The results show a very highly significant season effect (p < 0.001), with a higher rate of nucleus retention in autumn than spring: 91.1 versus 79.4 %, respectively. A very highly significant season effect was also recorded for nucleus rejection rate (p < 0.001), which was greater in spring than in autumn: 12.6 versus 7.7 %. Oyster mortality rate was up to six times higher in spring than in autumn (p < 0.001). Within the two seasons, there was no significant difference between the grafting experiments for any of the three variables, adding robustness to the inter-season results. Taking into account this seasonal variation effect, grafter skill had a significant impact on the three variables (p < 0.001), making it possible to rank grafters from most to least efficient. Aside from skill differences between grafters, grafting in autumn may significantly increase graft success. Water temperature and its indirect consequences could be one of the most important environmental factors implicated in overall efficiency. These findings may help the potential development of an annual grafting schedule according to season/ lagoon temperature as a way to maximize production yield for the black-lipped pearl oyster industry in French Polynesia.  相似文献   
26.
Oxidative stress owing to an imbalance between reactive oxygen species and antioxidants, such as coenzyme Q10 (CoQ10), is a major contributor to male infertility. We investigated the effects of the reduced form of CoQ10 (ubiquinol) supplementation on semen quality in dogs with poor semen quality. Three dogs received 100 mg of ubiquinol orally once daily for 12 weeks. Semen quality, serum testosterone, and seminal plasma superoxide dismutase (SOD) activity were examined at 2-week intervals from 2 weeks before ubiquinol supplementation to 4 weeks after the treatment. Ubiquinol improved sperm motility, reduced morphologically abnormal sperm, and increased seminal plasma SOD activity; however, it had no effect on testosterone level, semen volume, and sperm number. Ubiquinol supplementation could be used as a non-endocrine therapy for infertile dogs.  相似文献   
27.
Seventy-eight dogs with pain due to hip dysplasia were studied in a controlled, double-blind clinical trial to evaluate gold bead implantation as a pain-relieving treatment. The dogs were randomly assigned to two groups, 36 in the gold implantation group and 42 in the placebo group. Both groups were treated equally regarding anaesthesia, hair clipping and penetration of the skin with the same type of needle. The gold implantation group had small pieces of 24 carat gold inserted through needles at five different acupuncture points and the placebo group had the skin penetrated at five non-acupuncture points so as to avoid any possible effect of stimulating the acupuncture points. A certified veterinary acupuncturist marked the points, and two surgeons performed the implantations according to a randomisation code made in advance. After 14 days, three months and six months, the owners assessed the overall effect of the treatments by answering a questionnaire, and the same veterinarian examined each dog and evaluated its degree of lameness by examining videotaped footage of it walking and trotting. The treatment was blinded for both the owners and the veterinarian. There were significantly greater improvements in mobility and greater reductions in the signs of pain in the dogs treated with gold implantation than in the placebo group. The veterinarian's and the owners' assessments corresponded well.  相似文献   
28.
Interspecific interaction among sympatric ungulates is important in management and conservation. We investigated behavioral interference between sympatric wild or semidomestic reindeer (Rangifer tarandus tarandus) and sheep (Ovis aries) in two field studies and one enclosure experiment. For free-ranging wild and semidomestic reindeer, interference between the two species increased with decreasing distances, occurring only at less than 200 m and 30 m, for wild and semidomestic reindeer, respectively, and neither species consistently dominated the other. In a controlled, duplicated experiment we tested interference and confrontations at the feeding patch level among semidomestic reindeer and sheep within 40 × 50 m enclosures. When new reindeer or sheep were introduced into enclosures already occupied by reindeer, new reindeer resulted in significantly more interference and confrontations among individuals compared to new sheep; i.e., intraspecific interference was more prevalent than interspecific interference at equal densities. For all study areas, confrontations decreased with time after “first encounter,” indicating cohabituation. A sympatric use of pastures was not visually disruptive for recorded grazing behavior for either species.  相似文献   
29.
30.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号