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51.
为探究不同直径有腔卵泡中猪卵巢颗粒细胞的生理机能差异,以期为后续生殖毒理学研究奠定基础。采用剖剪法获取猪卵巢内三种直径范围的有腔卵泡(小型〈2mm,中型2-5mm,大型≥5mm)并获得颗粒细胞,台盼蓝染色方法计算细胞存活率,倒置显微镜下观察细胞形态并计算细胞纯度,实时定量方法检测促卵泡刺激素受体基因(FSHR)及促黄体生成素受体基因(LHR)的表达进一步鉴定颗粒细胞,四甲基偶氮唑蓝(MTT)法测定细胞生长曲线。结果显示从大中小三种不同直径有腔卵泡中获得的猪卵巢颗粒细胞存活率分别为68%、75%、72%,纯度分别为97%、95%、90%;细胞生长曲线表明,从24h开始进入对数生长期,并于120h达到最大值,且中型卵泡中获得的颗粒细胞生长增殖状态最佳;实时定量结果显示FSHR在猪三种直径的有腔卵泡颗粒细胞中均表达阳性,且呈现差异。  相似文献   
52.
A field study was conducted to estimate seasonal differences in follicular development in weaned sows and to evaluate the implication of these differences on seasonal infertility. A total of 110 sows were selected at weaning during winter–spring (WS, n = 58) and summer–autumn (SA, n = 52). Ovaries were scanned once daily from weaning to the onset of oestrus and twice daily from then until ovulation. Six sows during WS were removed from study for not showing growing follicles at weaning. Oestrus was evaluated twice daily from day 1 after weaning to day 14 post-weaning. One of 52 (1.9%) sows in WS and 9/52 (17.3%) in SA showed no signs of oestrus within 14 days of weaning (P < 0.05). The diameters of the follicles at weaning, at the onset of oestrus and just before ovulation were smaller (P < 0.01) in SA sows than in WS sows. There were fewer follicles in SA sows than in WS sows just before ovulation (P < 0.05). Fifty of 51 (98.0%) sows in WS and 31/43 (72.1%) sows in SA experienced a weaning-to-oestrus interval (WOI) of 3–6 days (P < 0.05). Fifty-one of 52 (98.1%) sows in WS and 43/52 (82.7%) sows in SA were inseminated; the percentage of pregnant sows that failed to farrow was lower in WS (1/51, 2.0%) than in SA (5/43, 11.6%; P < 0.05). The percentage of farrowed sows was greater in WS (46/51, 90.2%) than in SA (32/43, 74.4%; P < 0.05). Sows in WS had on average 1.5 more piglets than sows in SA (P < 0.05). Sows with a WOI of 3–6 days had lower rates of pregnancy losses (P < 0.05) and higher farrowing percentages (P < 0.01) than those with a WOI > 6 days, irrespective of season.  相似文献   
53.
To understand the ovarian basis for prolificacy of Bonga sheep, a total of 31 ewes were selected based on litter size (LS) records and divided into two groups: High Prolificacy (HP) (n = 20) with LS ≥ 2 and Low Prolificacy (LP) (n = 11) with LS = 1. At a synchronized estrus, follicular dynamics were determined using transrectal ultrasonography. Plasma estradiol concentrations were also monitored. In total 27 ewes were observed in estrus being 9/11 LP (82%) and 18/20 HP (90%). On the day of estrus (day 0), the mean number of large follicles was higher (p < .05) in HP (1.78 ± 0.19) than in LP (1.0 ± 0.28) ewes. Prior to estrus, more (p < .05) medium follicles were visible for HP compared to LP ewes. Plasma estradiol concentrations were higher in HP compared to LP ewes (18.91 ± 0.41 vs. 14.51 ± 0.65 pg/ml; p < .05) and similarly was ovulation number (2.3 ± 0.15 vs. 1.28 ± 0. 14; p < .05). Higher ovulation rates and litter size in Bonga sheep are evidenced by the previous presence of more large follicles and the existence of co‐dominance effects as most likely medium follicles are selected to ovulate.  相似文献   
54.
This study investigated the effects of human chorionic gonadotropin (hCG), 17-hydroxyprogesterone (17P) and testosterone (T) on the in vitro production of 17-estradiol (E2) by isolated ovarian follicles of the rainbow trout (Oncorhynchus mykiss). 17P at 100 ng ml-1, and hCG at 100 IU ml-1 stimulated E2 production relative to controls, whereas lower doses were ineffective. T was the most effective in stimulating E2 production, followed by 17P and hCG respectively. The timecourse of E2 production was investigated for both static culture, and incubations with media replacement, with follicles being exposed to hormone treatment for 30 min, 1 or 3 h, or constantly. E2 production was observed after 30 min, 3 and 3-6 h in response to T, 17P and hCG respectively. Under static culture, E2 levels reached maximal levels in 6 h. Longer incubations resulted in further metabolism of E2 to E2-glucuronide, which resulted in the blurring of treatment effects after 18 h. Incubations with media replacement resulted in higher E2 production than in static culture. The results indicate that a 6 h incubation period is sufficient to produce significant increases in E2 production in response to hCG, 17P and T, and that incubations longer than 12 h result in losses E2 from the incubation media. These findings have implications for the validity of using static cultures to examine the effects of hormone treatment on the activity of steroid converting enzymes in vitro.  相似文献   
55.
This article briefly reviews the current status of investigations, mainly based on the amago salmon,Oncorhynchus rhodurus, on the mechanisms of synthesis and action of 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-diOHprog). Pituitary gonadotropin is of primary importance in triggering meiotic maturation in teleost oocytes. However, the maturational action of gonadotropin is not direct, but is mediated by the follicular production of maturation-inducing substance (MIS). It is now well established that 17α,20β-diOHprog is the major MIS of salmonids. Production of this steroid occursvia the interaction of two distinct cell layers, the thecal and granulosa cell layers (2-cell type model). The first step of the stimulating effect of gonadotropin in both layers is the receptor-mediated activation of adenylate cyclase and formation of cAMP. Our findings suggest that the major stimulating action of gonadotropin on 17α,20β-diOHprog biosynthesis is due to the stimulation of 17α-hydroxyprogesterone production by the thecal layer and the selective induction of thede novo synthesis of 20β-hydroxysteroid dehydrogenase in the granulosa layer. 17α,20β-diOHprog acts at the surface of the oocyte. The early steps following 17α,20β-diOHprog action involve the formation of the major cytoplasmic mediator of this steroid, maturation-promoting factor (MPF). It was shown that goldfish MPF induces meiotic maturation inXenopus oocytes andvice versa. The chemical characterization of fish MPF is important for our understanding of the precise mode of maturational action of 17α,20β-diOHprog.  相似文献   
56.
Effect of sodium nitroprusside (SNP), a nitric oxide (NO) donor, on in vitro survival, growth, steroidogenesis, and apoptosis of buffalo preantral follicles (PFs) was investigated. PFs (200~250 µm) were isolated by micro-dissection and cultured in 0 (control), 10-3, 10-5, 10-7, and 10-9 M SNP. To examine the reversible effect of SNP, PFs were cultured with 10-5 M SNP + 1 mM Nω-nitro-L-arginine methyl ester (L-NAME) or 1.0 µg hemoglobin (Hb). The results showed that greater concentrations of SNP (10-3, 10-5, 10-7 M) inhibited (p < 0.05) FSH-induced survival, growth, antrum formation, estradiol production, and oocyte apoptosis in a dose-dependent manner. However, a lower dose of SNP (10-9 M) significantly stimulated (p < 0.05) the survival, growth, antrum formation, follicular oocyte maturation, and stimulated progesterone secretion compared to the control. A combination of SNP + L-NAME promoted the inhibitor effect of SNP while a SNP + Hb combination reversed this effect. Nitrate and nitrite concentrations in the culture medium increased (p < 0.05) in a dose-dependent manner according to SNP concentration in the culture medium. At higher concentrations, SNP had a cytotoxic effect leading to follicular oocyte apoptosis whereas lower concentrations have stimulatory effects. In conclusion, NO exerts a dual effect on its development of buffalo PFs depending on the concentration in the culture medium.  相似文献   
57.
牛腔前卵泡在体外无血清培养中发育为有腔卵泡   总被引:13,自引:3,他引:10  
用无血清培养系统研究了牛腔前卵泡的体外培养。直径为100-200μm的牛腔前卵泡在添加L-谷氨酰胺、BSA、睾酮、转铁蛋白和硒的McCoy′s 5a培养液中培养,卵泡保持正常的形态结构并持续生长,培养10d左右形成贸泡腔,成腔率约50%。培养液中添加胰岛素对卵泡直径的增长和卵泡腔的形成有明显的促进作用,但添加FSH对腔前卵泡的生长未表现促进作用。  相似文献   
58.
[目的]研究猪有腔卵泡发育和闭锁中颗粒细胞凋亡与卵泡液类固醇激素的变化,为了解猪有腔卵泡发育与闭锁的调控机理提供参考.[方法]从猪卵巢分离完整有腔卵泡,按质量分为健康卵泡、早期闭锁卵泡和晚期闭锁卵泡3类;再按卵泡直径大小分为大卵泡组(>5 mm)、中卵泡组(3~5 mm)和小卵泡组(<3 mm)3组,制作完整有腔卵泡的...  相似文献   
59.
为探讨FSH对牛腔前卵泡体外发育的影响,在McCoy’s 5a基础无血清培养液中,分别加入浓度为0、1、10、50及100 ng/mL FSH,观察培养不同时间腔前卵泡的生长和存活情况。结果显示,在培养6 d后添加50及100 ng/mL FSH组腔前卵泡及其卵母细胞直径都较对照组及其他处理组有较大幅度的增长(P<0.01);添加10 ng/mL以上FSH组腔前卵泡在培养后期的体外存活率也有明显提高(P<0.05),表明适宜浓度的FSH对培养后期腔前卵泡体外发育具有显著的促进作用。  相似文献   
60.
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