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   313篇
  免费   7篇
  国内免费   1篇
林业   31篇
农学   9篇
基础科学   5篇
  102篇
综合类   29篇
农作物   24篇
水产渔业   33篇
畜牧兽医   60篇
园艺   14篇
植物保护   14篇
  2023年   3篇
  2022年   4篇
  2020年   1篇
  2019年   7篇
  2018年   1篇
  2017年   2篇
  2016年   10篇
  2015年   7篇
  2014年   12篇
  2013年   15篇
  2012年   12篇
  2011年   17篇
  2010年   23篇
  2009年   19篇
  2008年   19篇
  2007年   18篇
  2006年   21篇
  2005年   26篇
  2004年   13篇
  2003年   9篇
  2002年   17篇
  2001年   5篇
  2000年   4篇
  1999年   4篇
  1998年   2篇
  1997年   2篇
  1996年   1篇
  1995年   7篇
  1994年   3篇
  1993年   1篇
  1992年   1篇
  1991年   3篇
  1990年   3篇
  1989年   1篇
  1988年   2篇
  1987年   1篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1980年   3篇
  1978年   1篇
  1977年   2篇
  1976年   2篇
  1974年   3篇
  1970年   1篇
  1953年   1篇
  1950年   1篇
  1949年   2篇
  1932年   1篇
排序方式: 共有321条查询结果,搜索用时 46 毫秒
101.
Farmed Atlantic cod with a mean weight of 4.8 kg were maintained for 9 weeks in sea cages and fed diets where the dietary fishmeal component was substituted with increasing proportions (0%, 22%, 63% and 100%) of meal from Antarctic krill, Euphausia superba. Wild‐caught cod were included in the study as external control. At termination of feeding, all fish were slaughtered and muscle pH was immediately recorded. The fish were then stored on ice for three days and assessed for muscle pH and objective (skin and fillet colour, and fillet texture) and subjective (sensory evaluation) quality criteria. Replacement of fishmeal with krillmeal in the diets resulted in the skin colour above and below the lateral line to be more red than the control group without krillmeal substitutions, even though this difference was not significant, and with more yellow hue. Additions of krillmeal increased the muscle whiteness and yellow hue compared with the control group and wild fish. There was no difference in red hue between the groups. Muscle pH, texture or sensory attributes were unaffected by dietary inclusion level of krillmeal. Wild‐caught cod deviated in several aspects from the farmed cod. It is concluded that the replacement of fishmeal with Antarctic krillmeal in the diets two months before slaughter did not move the sensory attributes more towards wild fish.  相似文献   
102.
Atlantic salmon (Salmo salar) was grown in sea cages from 700 g to a market size of 3.2 kg on diets containing either 29% Peruvian high polyunsaturated fatty acids (PUFA) fish oil (FO) or 29% soybean oil (SO) as oil source. Chemical analyses and a triangular consumer test were performed on fresh muscle, while colour, texture and liquid holding capacity (LHC) analyses were performed on both fresh muscle, frozen muscle (stored for 3 months) and smoked salmon. The growth and chemical composition of flesh was not affected by the dietary treatment. The muscle fatty acid (FA) profile was reflected by the dietary oil source, and the amount of malondialdehyde (MDA) was threefold higher in the salmon fed FO than SO. Muscle pigment concentration was significantly different (p < 0.01) with 7.9 mg kg–1 for FO and 5.6 mg kg–1 for SO fed salmon, respectively. This result was also significantly (p < 0.05) reflected in the difference between the instrumentally measured colour of fresh, frozen and smoked muscle, and visual impressions of fresh and frozen muscle. Gaping, texture and liquid holding capacity was not affected by the dietary treatment, and the consumer panel did not detect any differences between the dietary groups. SO can be used as a dietary oil source in the grow-out phase of salmon production without sacrificing product quality in terms of texture, liquid holding capacity and consumer preference. However, a total substitution of high PUFA fish oil by SO in diets for salmon grown to market size, affects muscle colour and the FA profile significantly. (p < 0.05).  相似文献   
103.
Zusammenfassung Die ursprüngliche Naumburger Malus-Artenkollektion wurde in das Institut für Obstforschung Dresden-Pillnitz überführt. Sie umfaßt 237 Arten und Varietäten und damit die wichtigsten Vertreter der 5 Sektionen vonMalus - Malus, Sorbomalus, Chloromeles, Eriobolus, Docyniopsis (nachRehder 1954). Die bereits vorliegenden Untersuchungsergebnisse an dieser Kollektion über Pollenfertilität, Apomixis, Schorf-, Mehltau- und Blutlausresistenz sowie Virustoleranz werden mitgeteilt.Auf die nationale und internationale Bedeutung dieses Genfonds, der für den Austausch zur Verfügung steht, wird hingewiesen.
Genetic resources ofMalus in the GDR and their utilization
Summary The collection ofMalus germplasm originally located in Naumburg has been transfered to the Institute of Fruit Research in Dresden-Pillnitz. It contains 237 species and forms and therewith important representatives of the 5 sections ofMalus - Malus, Sorbomalus, Chloromeles, Eriobolus, Docyniopsis (according toRehder 1954). The results already obtained on the basis of this germplasm concerning pollen fertility, apomixis, resistance to scab, mildew, woolly aphid, and virus tolerance are presented here. The national and international importance of thisMalus collection which is available for distribution is stressed.

Malus
Malus, . , -. 237 :Malus, Sorbomalus, Chloromeles, Eriobolus, Docyniopsis ( , 1954). , , , , , , , . , , , .
  相似文献   
104.
105.
Receptors of the immunoglobulin-like superfamily are critically involved in virtually every aspect of immune responses. One large chromosomal area encoding such immunoregulatory receptors is the leukocyte receptor cluster. Here we review various aspects of the chicken Ig-like receptor (CHIR) family, located on microchromosome 31, an orthologous position to the mammalian leukocyte receptor cluster. The CHIR family has been massively expanded with over hundred CHIR genes that are further distinguished into activating, inhibitory and bifunctional receptors. Comparisons of various features such as amino acid motifs, genomic structure, expression and associated adaptor molecules reveal the homology of CHIR to both the killer Ig-like and the leukocyte Ig-like receptor families, with most pronounced correlation of certain CHIR to the NK cell receptor KIR2DL4. To date the CHIR ligands remain largely obscure with the exception of CHIR-AB1 that binds to chicken IgY. Detailed analyses of CHIR-AB1, its crystal structure, the interaction to IgY and functional capabilities allow us to draw conclusions regarding Fc receptor phylogeny and function.  相似文献   
106.
Moringa oleifera, either fresh or ensiled, was compared with Elephant grass as a main feedstuff for dairy cows. To test the effects feed had on milk yield, milk composition, ration digestibility, and the organoleptic characteristics of milk, six lactating dairy cows were used in a Changeover 3 × 3 Latin Square experiment, replicated twice. With equal intake of metabolizable energy the intake of protein and fiber differed (p < 0.001) between all diets where fresh Moringa had the highest and the Elephant grass diet had the lowest intake. Compared with the control diet, ensiled Moringa had higher digestibility (P < 0.05) of both protein and fiber. With the exception of DM digestibility, no digestibility differences were found between fresh Moringa and Moringa silage treatments. Milk yield did not differ between any of the treatments and averaged 13.7 kg cow day−1. Milk composition was similar among all treatments. Milk from the fresh Moringa treatment, however, had a grassy flavor and aroma, significantly different from the other two treatments, even though it was normal in color and appearance. No organoleptic differences were found between milk from the control treatment and the Moringa silage treatment. The conclusion is that Moringa silage can be fed to dairy cows in large quantities to produce the same quantity and quality of milk as traditional diets.  相似文献   
107.
Oligodeoxynucleotides (ODNs) with unmethylated CpG dinucleotide motifs may be useful as non-specific immune system stimulants and adjuvants for protein or nucleic acid vaccines in humans and other primates. They may also be useful in cancer immunotherapy and in the modulation of allergic responses or mucosal immunity. To begin to determine the potential utility of CpG ODN technology in small animal veterinary medicine, we developed procedures to analyze the effects of CpG ODN on canine and feline blood, spleen and lymph node (LN) cells. We find that certain CpG ODN cause good lymphocyte proliferation (as monitored by [(3)H]-thymidine incorporation) in both canine and feline spleen and LN cells, but not in blood. This overall stimulatory effect of CpG ODN on spleen and LN cells is CpG dependent. The reverse sequences, GpC ODNs, do not cause significant lymphocyte proliferation in the cat; however, dogs are more sensitive to stimulation by the non-specific immune effects of the phosphorothioate backbone. We conclude that unmethylated CpG ODNs may also have potential uses as immune stimulants for vaccines and other antimicrobial agents in veterinary medicine for companion animals.  相似文献   
108.
109.
Auditory brain stem response testing in anesthetized horses   总被引:1,自引:0,他引:1  
Auditory brain stem response testing, using insert earphones, was performed in 10 healthy horses given general anesthesia. The procedure involved clicks of alternating polarity delivered at a rate of 25 clicks/s. Wave forms, including five peaks, were commonly identified. Latencies were measured in milliseconds for waves I through V for all intensities. Latencies of all waves decreased as stimulus intensity increased. For waves I through V, a least-squares regression line was determined for each horse, using all responses between 87-dB sound pressure level (SPL) and 136-dB SPL, inclusive. Slopes were significantly (P less than 0.05) less than zero for waves I through IV, but not for wave V. Peak latencies of each wave averaged at 87-dB SPL for waves I through V were 1.73, 2.6, 3.82, 4.80, and 5.71 ms, respectively; latencies of these five waves at 136-dB SPL were 1.36, 2.2, 3.06, 3.92, and 4.71 ms, respectively. The decrease in latency among the five waves ranged from 0.13 to 0.004 ms/dB. When peak values were below 87-dB SPL, waves became essentially unrecognizable.  相似文献   
110.
Genetic parameters were estimated for prevalences of primary cataract (CAT), persistent pupillary membrane (PPM) and distichiasis (DIST) in 615 single-colored and 617 multi-colored English Cocker Spaniels (ECS) bred in the German kennel club for Spaniels (Jagdspaniel-Klub e.V.). CAT or CAT diagnosed in dogs up to three and a half years of age (early-onset cataract, CAT-early) and CAT diagnosed in dogs over three and a half years of age (late-onset cataract, CAT-late), PPM and DIST were included as binary traits in multivariate genetic analyses. Heritabilities on the underlying liability scale were 0.15 for CAT, 0.34 for CAT-early, 0.13 for CAT-late, 0.46 for PPM, and 0.62 for DIST in single-colored ECS and 0.06 for CAT, 0.13 for CAT-early, 0.14 for CAT-late, 0.10 for PPM, and 0.61 for DIST in multi-colored ECS. There were indications for a different genetic basis of CAT-early and CAT-late in single-colored ECS as genetic correlations were close to zero. In multi-colored ECS, a similar tendency for CAT-early and CAT-late could be observed.  相似文献   
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