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101.
102.
Kisspeptin(简称Kiss或者Kp)是由KISS1/Kiss1基因编码的一种下丘脑神经肽,通过其受体KissR(也称作GPR54)的介导参与了多种生理过程,如抑制肿瘤转移和参与生殖调控。目前,尽管在鲤形目(Cypriniformes)、鲈形目(Perciforms)、鲽形目(Pleuronectiforms)、鲀形目(Tetraodontiforms)、颌针目(Beloniforms)、鲉形目(Scorpaeniformes)、鲑形目(Salmoniformes)及鳕形目(Gadiformes)等多种鱼类中均鉴定出了kiss/kissr基因,但Kiss/KissR系统在鱼类生殖调控中的精确作用及其分子机制尚未完全阐明。尤其是在鱼类中存在2种kiss及3种kissr基因,Kiss/KissR系统对鱼类生殖调控的作用方式更加复杂。本文简要总结鱼类Kiss及其受体的研究进展,并对Kiss的生理学功能、信号转导机制以及kiss/kissr表达调控研究进行概括讨论,旨在加深对鱼类Kiss/KissR系统的认识和了解,为后续研究指明方向。 相似文献
103.
以本实验室建立的三疣梭子蟹(Portunus trituberculatus)全同胞家系为研究对象,通过连续观测6代三疣梭子蟹近交家系的抱卵量、排幼量、孵化率、单位体重抱卵量、单位体重排幼量及幼体发育各阶段的变态率6个指标来评价近交对三疣梭子蟹繁殖性能的影响.方差分析显示,在实验亲蟹的规格大小对测量数据无影响的条件下,近交系数每增加10%,各近交代与非近交代F1m在单位体重抱卵量与单位体重排幼量的差异不显著(P>0.05),这2个指标的近交衰退系数分别为-2.789%~-6.620%和-1.188%~-5.938%;孵化率的差异也不显著(P>0.05),衰退系数为-1.859%~-7.222%,表明没有明显的近交衰退;由溞状幼体(Z)阶段、大眼幼体(M)阶段到Ⅱ期幼蟹阶段的变态率变化趋势可知,随着近交代数的增加,各阶段的变态率呈下降趋势. 相似文献
104.
The fat snook, Centropomus parallelus, is a commercially valuable marine fish species with potential for aquaculture. This paper describes the development of technology
for mass production of fat snook juveniles at the Experimental Fish Hatchery of the Universidade Federal de Santa Catarina,
focusing on research about reproduction, larviculture, and juvenile rearing. Induced spawning of wild fat snook was first
achieved in 1991 with a single injection of human chorionic gonadotropin (hCG). There was a substantial increase in egg quality
when broodstock was conditioned in maturation rooms and induced to spawn. Different dosages of luteinizing hormone-releasing
hormone analogue (LHRHa) with saline injection and colesterol implant were also tested. As fat snook exhibits group-synchronous
oocyte development, females could be induced to spawn (with 35–50 μg kg−1 of LHRHa) once a month, resulting in up to four consecutive spawnings. Results of larval culture were highly variable at
the beginning; survival rates were frequently around 1% until the juvenile stage. Several experiments were conducted to evaluate
the effect of environmental factors and feeding quality on survival and growth. With the improvement of the spawning induction
technique and better larviculture practices, survival rates increased to 10–30%. Studies on the particular requirements of
juveniles in terms of stocking density, feeding, nutrition, and environmental factors were also performed in order to improve
growth rates and feed utilization. The present study demonstrates the feasibility of mass production of fat snook juveniles.
However, further research is needed to develop cost-effective grow-out technology. 相似文献
105.
In this study we examined the endocrine mediation between environmental factors (temperature and photoperiod) and the brain–pituitary–gonadal
axis in females of pejerrey Odontesthes bonariensis. Changes in the expression of brain gonadotropin-releasing hormones (GnRHs) and gonadotropin (GtH) subunit [follicle stimulating-β
(FSH-β), luteinizing hormone-β (LH-β), glycoprotein hormone-α (GPH-α)] genes, plasma gonadal steroids [estradiol (E2) and testosterone (T)], gonadal histology, and gonadosomatic index (GSI) in adult females exposed to combinations of short-day
(8 h) or long-day (16 h) photoperiods and low (12°C) or high (20°C) temperatures after winter conditions (8 h light, 12°C)
were analyzed. Pejerrey females kept under the short photoperiod had low GSIs, and their ovaries contained only previtellogenic
oocytes regardless of the experimental temperature. In contrast, females exposed to the long photoperiod had high GSIs and
ovaries with vitellogenic oocytes at both temperatures. These fish also showed a significantly higher expression of sGnRH,
pjGnRH, cGnRH-II (the three different GnRH variants found to date in the pejerrey brain), FSH-β, LH-β and GPH-α genes and
plasma E2 levels than those at the shorter photoperiod. No significant changes were observed in plasma T levels. Based on these results,
we concluded that the increase in day length but not that of temperature triggers the maturation of pejerrey females after
the winter period of gonadal rest and that this occurs by an integrated stimulation of the various components of the brain–pituitary–gonad
axis. 相似文献
106.
107.
萨能奶山羊在贵州的繁殖性能观测 总被引:1,自引:0,他引:1
对贵州牧草种籽繁殖场饲养的萨能奶山羊的初情期、初配年龄、发情周期、发情持续期、发情季节、妊娠期、产羔率、羔羊公母比例等八项繁殖性能指标进行观察测定,并与西北农业大学的萨能奶山羊进行比较分析,从而看出在贵州饲养的奶山羊具有明显的早熟性。 相似文献
108.
M.C. Fuentes S. Calsamiglia C. Snchez A. Gonzlez J.R. Newbold J.E.P. Santos L.M. Rodríguez-Alcal J. Fontecha 《Livestock Science》2008,113(2-3):144-154
A total of 356 early lactation multiparous Holstein cows were used in a randomized complete block design to determine the effects of feeding extruded linseed on milk production and composition, and reproductive performance. Forty of these cows were randomly selected to study the effects of extruded linseed on milk fatty acid (FA) profile, individual feed intake and prostaglandin secretion. Cows were fed a 40:60 forage to concentrate ratio diet (17.9% CP, 27.7% NDF and 6.0% EE) ad libitum that was similar in composition between treatments except for the protein supplements that differed and were control (CTR: 4.9% extruded soybean) and linseed (LIN: 5.5% extruded linseed). Individual DM intake measured at 40 (23.0 kg/d) and 90 (24.2 kg/d) days in milk, and milk yield (45.0 kg/d) were not affected by treatment, but the lower (P < 0.05) milk fat percentage in cows fed LIN (2.65%) compared with CTR (2.86%) resulted in lower (P < 0.05) 4.0% fat-corrected milk yield for cows fed LIN (35.4 kg/d) compared with CTR (37.7 kg/d). Milk protein content was higher (P < 0.05) in LIN (3.04%) than in CTR (3.00%). The concentration of saturated FA was lower (P < 0.05) in milk fat from LIN (56.2%) compared with CTR (60.2%). Monounsaturated FA (35.7 vs. 32.7%) and polyunsaturated FA (8.0 vs. 6.9%) were higher in LIN (P < 0.05) than in CTR. Supplementation with LIN also increased (P < 0.05) the proportion of vaccenic acid (2.21 vs. 1.55%), total conjugated linoleic acid (0.91 vs. 0.72%) and n-3 FA (1.21 vs. 0.54%) in milk compared with CTR. Plasma concentrations of prostaglandin metabolite were numerically lower in LIN (106 pg/ml) compared with CTR (120 pg/ml) (P = 0.16) but reproductive performance was similar between treatments. In summary, extruded linseed reduced milk fat percentage and 4.0% fat-corrected milk yield and increased milk protein percentage and the content of healthy FA in milk without modifying DM intake, milk yield and reproductive performance. 相似文献
109.
硒是动物机体必需的微量元素,参与体内许多重要的生理活动,而酵母硒以其易吸收及毒性小等特点受到广泛关注。文章主要介绍酵母硒对奶牛生产性能、抗氧化能力、免疫功能、繁殖性能方面的影响。 相似文献
110.
实验结果显示,各龄雄鹅在非生殖期血清中促黄体生成素(LH)、促卵泡刺激素(FSH)和雌二醇(E2)在血清中的含量都低于5.0 mu/ml,其差异性难以比较.4种不同种龄的雄鹅在垂体泌乳素(PRL)和孕酮(P)水平上没有显著差异.在睾酮(T)激素水平上差异很明显,即2龄种鹅>1龄种鹅>3龄种鹅>4龄种鹅.可见在4个种龄的雄鹅中,2龄种鹅体内的睾酮最高,其生殖能力可能最强。 相似文献