全文获取类型
收费全文 | 1481篇 |
免费 | 99篇 |
国内免费 | 1篇 |
专业分类
林业 | 94篇 |
农学 | 96篇 |
基础科学 | 3篇 |
232篇 | |
综合类 | 77篇 |
农作物 | 277篇 |
水产渔业 | 157篇 |
畜牧兽医 | 527篇 |
园艺 | 24篇 |
植物保护 | 94篇 |
出版年
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 51篇 |
2020年 | 35篇 |
2019年 | 40篇 |
2018年 | 53篇 |
2017年 | 45篇 |
2016年 | 55篇 |
2015年 | 53篇 |
2014年 | 78篇 |
2013年 | 82篇 |
2012年 | 116篇 |
2011年 | 131篇 |
2010年 | 82篇 |
2009年 | 68篇 |
2008年 | 87篇 |
2007年 | 99篇 |
2006年 | 87篇 |
2005年 | 67篇 |
2004年 | 62篇 |
2003年 | 56篇 |
2002年 | 55篇 |
2001年 | 35篇 |
2000年 | 28篇 |
1999年 | 13篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1972年 | 3篇 |
1967年 | 4篇 |
1966年 | 9篇 |
1965年 | 4篇 |
1964年 | 2篇 |
1963年 | 1篇 |
1961年 | 2篇 |
1960年 | 2篇 |
1938年 | 1篇 |
排序方式: 共有1581条查询结果,搜索用时 545 毫秒
21.
22.
Hyesuck An Mi‐Jung Kim Kwangjae Park Keechae Cho Bongseong Bae Jaewoo Kim Jeong‐In Myeong 《Journal of the World Aquaculture Society》2012,43(1):73-83
The Korean rockfish, Sebastes schlegeli, is a valuable and intensively exploited species in Korea. We discuss the genetic diversity and genetic structure of four Korean rockfish populations using eight microsatellite loci. In total, 161 different alleles from 138 individuals were observed. Average allele number per locus ranged from 2.5 to 23 and allelic richness varied from 13.38 to 14.63 within a population. Despite a long history of stocking practices, we found very high levels of polymorphism (mean heterozygosity = 0.810), which is comparable to other congeneric species. No significant difference in genetic diversity and molecular genetic variance (FST and RST) was observed among four local samples (P > 0.1). Little indication of contemporary inbreeding (FIS= 0.051) or population structure (K = 1) was detected. This absence of differentiation may reflect high levels of gene flow along the coast of Korea. Our study demonstrates that rockfish in Korea should be managed as a single unit. Currently, the species does not appear to be genetically threatened, but the potential for a rapid loss of genetic diversity remains. This information on the genetic characteristics of Korean rockfish populations has important implications for fisheries management and conservation efforts, and will aid in the sustainable exploitation of the fishing resources and the preservation of biodiversity. 相似文献
23.
In a feeding experiment (54 piglets) and a slaughtering test for the registration of tract and digesta properties (15 piglets) the influence of rations with 69% rye (R) or wheat (W) with and without a supplement of 200 mg of the chinoxalin derivate Bisergon/kg DM (rations RB and WB) was studied. In the sequence R, RB, W and WB the feed intake in the test period of 3 weeks after weaning amounted to 581, 651, 583 and 764 g, weight gain to 314, 365, 319 and 424 g per animal and day. In the same sequence the concentration of organic acids in the stomach amounted to 41, 5, 25 and 18 mmol per 100 g dry matter and in the colon to 106, 83, 64 and 62. Bisergon caused a redistribution of the digesta from the stomach to the large intestine and a more rapid emptying of the stomach as well. Rye caused extreme fermentation processes in the front part of the tract and Bisergon clearly has ergotropic qualities for the stabilization of the intestinal flora. 相似文献
24.
Crowell-Davis SL Seibert LM Sung W Parthasarathy V Curtis TM 《Journal of the American Veterinary Medical Association》2003,222(6):744-748
OBJECTIVE: To evaluate use of clomipramine, alprazolam, and behavior modification for treatment of storm phobia in dogs. DESIGN: Prospective open clinical trial. ANIMALS: 40 dogs with storm phobia. PROCEDURE: Dogs received clomipramine at a dosage of 2 mg/kg (0.9 mg/lb), PO, every 12 hours for 3 months; then 1 mg/kg (0.45 mg/lb), PO, every 12 hours for 2 weeks; then 0.5 mg/kg (0.23 mg/lb), PO, every 12 hours for 2 weeks. Alprazolam was given at a dosage of 0.02 mg/kg (0.009 mg/lb), PO, as needed 1 hour before anticipated storms and every 4 hours as needed. Desensitization and counter-conditioning were conducted at home by the caregiver with an audio simulation of storm sounds that had induced a fear response during evaluation. RESULTS: 30 of the 32 dogs that completed the study had a degree of improvement, as measured by caregivers' global assessment. Two caregivers considered the storm phobia to be resolved. Panting, pacing, trembling, remaining near the caregiver, hiding, excessive salivation, destructiveness, excessive vocalization, self-trauma, and inappropriate elimination all decreased significantly during treatment. Improvement was greater during true storms (rain, thunder, and lightning) than during rain only. Response to audio simulation did not change during treatment. Four months after the study, improvement was maintained. CONCLUSIONS AND CLINICAL RELEVANCE: The combination of clomipramine, alprazolam, and behavior modification can be effective in decreasing or eliminating storm phobia. Improvement could not be evaluated by use of audio simulation of a storm. 相似文献
25.
Sung HW 《Avian diseases》2002,46(3):517-524
The incidence of Marek's disease (MD), an important neoplastic disease of chickens, suddenly increased in 1997 in Korea. Most MD cases of this country were detected in chickens over 20 wk of age. Five MD viruses were isolated from field flocks in which severe MD losses had occurred, and one of the viruses was studied to compare its pathotype with the prototype JM strain. The isolate KOMD-IC induced severe depression not only in body weight but also in relative bursal weight, and the depression by KOMD-IC was more severe than that induced by JM strain. In addition, the incidence of MD tumor caused by KOMD-IC was higher than that caused by the JM strain. The protective capacity of several MD vaccines was studied against challenge with KOMD-IC. The protective levels of several MD vaccines such as herpesvirus of turkeys (HVT), HVT plus SB1, and Rispens were usually lower against challenge with KOMD-IC than those challenged with JM strain, even if the chickens vaccinated with serotype 1 were not completely protected against challenge with KOMD-IC. The above results indicate that the virulence of KOMD-IC isolated recently was increased, and the increase of MD outbreak in Korea may be related to the virulence increase of the virus. Various MD vaccine programs were applied to reduce MD loss to a broiler breeder farm where severe MD loss had occurred. Serotype 1 vaccine could dramatically decrease the mortality due to MD, and the best results were obtained from the flocks vaccinated with bivalent vaccine of Rispens and HVT. 相似文献
26.
Choi M Seo M Jung J Lee K Yoon J Chang D Park RD 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(1):17-21
For the evaluation of canine gastric motility with ultrasonography, contraction number of pyloric antrum and gastric emptying time (GET) by area and volume method developed by Bolondi et al.'s method were studied in 14 dogs. All experimental dogs were administered with saline and soup solution (10 ml/kg, B.W.). The mean values of contraction number of pyloric antrum in saline and soup group were 4.19 +/- 1.30/min and 4.82 +/- 0.65/min before feeding, and overall mean values were 4.66 +/- 1.37/min and 5.13 +/- 1.71/min, respectively. The mean values of the GET by area and volume method were 36.73 +/- 11.27, 40.00 +/- 8.87 min in saline group and 61.35 +/- 17.58, 59.11 +/- 14.46 min in soup group. In the GET in saline and soup groups, there was no significant difference between the area and volume method (p>0.05). Therefore, Bolondi et al.'s method by ultrasound can be used to evaluate the antropyloric motility and gastric emptying time with area and volume methods. The area method is easier to determine the GET than the volume method, but the latter is more accurate. 相似文献
27.
The pharmacokinetics of furathiocarb were studied in vivo in male Sprague-Dawley rats following dermal treatment. HPLC and post-column derivatization were used for the analysis of furathiocarb and its metabolites (carbofuran, 3-hydroxycarbofuran and 3-ketocarbofuran). Carbofuran and 3-hydroxycarbofuran were detected in plasma and urine rather than furathiocarb. 3-Ketocarbofuran, another potential metabolite, was not observed in any sample. The concentration of carbofuran was higher than that of 3-hydroxycarbofuran in plasma, but the reverse was the case in urine. The corresponding area under the plasma concentration-time curve, Tmax, and Cmax values of carbofuran and 3-hydroxycarbofuran for 1500 mg kg-1 doses were 2.4-8.0 mg equiv hml-1, 12 h and 0.1-0.4 mg equiv ml-1, respectively. T1/2 was calculated only for 3-hydroxycarbofuran (28 h). Two metabolites were excreted in a dose-dependent manner without saturation. 相似文献
28.
Data collected by the National Livestock Research Institute of the Rural Development Administration of Korea were used to estimate genetic parameters for yearling (YWT, n = 5,848), 18-mo (W18, n = 4,585), and slaughter (SWT, n = 2,279) weights for Korean Native cattle. Nine animal models were used to obtain REML estimates of genetic parameters: DP-2 included genetic, uncorrelated dam, and residual random effects; DQ-2 included genetic, sire x region x year-season interaction, and residual random effects; DPQ-2 was based on DQ-2 but included both interaction and dam effects; DMP-2 was based on DP-2 but with dam effect partitioned to include maternal genetic and permanent environmental effects; and DMPQ-2 was based on DMP-2 but also included sire interaction effects. Those five models included two fixed factors: region x year-season and age of dam x sex effects. Models DP-3, DQ-3, DPQ-3, and DMPQ-3 were based on DP-2, DQ-2, DPQ-2, and DMPQ-2 but included as a third fixed factor whether or not identification of the sire was known. Estimates of heritability with DMPQ-3 for YWT, with DPQ-3 for W18 and SWT when analyzed with single-trait analyses were .14, .11, and .17, respectively, and were nearly the same with bivariate analyses. Estimate of maternal heritability for YWT from single-trait analysis was .04, with estimates for other traits near zero. For bivariate analyses, the estimate for YWT was .01. With single trait analysis, estimate of the direct-maternal genetic correlation for YWT was negative (-.81). Estimates of direct genetic correlations between YWT and W18, YWT and SWT, and W18 and SWT were .99, 1.00, and .97, respectively. Estimates of environmental correlations varied from .60 to .81; the largest was between W18 and SWT. Including a fixed factor for whether sire identification was missing or not missing reduced the estimate of heritability for slaughter weight. The results suggest that the sire x region x year-season interaction is important for yearling weight and may be needed in a model for slaughter weight. Maternal effects may be of slight importance for yearling weight but of no importance for W18 and SWT. Models for national cattle evaluations for Korean Native cattle for YWT should be considered that include maternal genetic and permanent environmental as well as sire x region x year-season interaction effects, but those effects seem not to be needed for models for W18 and SWT. Not much reranking of sires occurred when ranked was based on the different models for W18 and SWT. 相似文献
29.
Genetic characterization of canine rotavirus isolated from a puppy in Korea and experimental reproduction of disease. 总被引:3,自引:0,他引:3
30.