全文获取类型
收费全文 | 2464篇 |
免费 | 234篇 |
专业分类
林业 | 5篇 |
农学 | 2篇 |
基础科学 | 4篇 |
8篇 | |
综合类 | 12篇 |
农作物 | 2篇 |
水产渔业 | 21篇 |
畜牧兽医 | 2638篇 |
园艺 | 2篇 |
植物保护 | 4篇 |
出版年
2024年 | 1篇 |
2023年 | 53篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 96篇 |
2019年 | 4篇 |
2018年 | 60篇 |
2017年 | 67篇 |
2016年 | 41篇 |
2015年 | 69篇 |
2014年 | 106篇 |
2013年 | 110篇 |
2012年 | 71篇 |
2011年 | 85篇 |
2010年 | 81篇 |
2009年 | 86篇 |
2008年 | 66篇 |
2007年 | 54篇 |
2006年 | 35篇 |
2005年 | 28篇 |
2004年 | 58篇 |
2003年 | 56篇 |
2002年 | 66篇 |
2001年 | 64篇 |
2000年 | 56篇 |
1999年 | 68篇 |
1998年 | 104篇 |
1997年 | 101篇 |
1996年 | 80篇 |
1995年 | 79篇 |
1994年 | 71篇 |
1993年 | 90篇 |
1992年 | 106篇 |
1991年 | 80篇 |
1990年 | 92篇 |
1989年 | 76篇 |
1988年 | 70篇 |
1987年 | 76篇 |
1986年 | 34篇 |
1985年 | 48篇 |
1984年 | 34篇 |
1983年 | 48篇 |
1982年 | 18篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有2698条查询结果,搜索用时 31 毫秒
991.
992.
993.
994.
Rebekah C. HebertDonald L. Thompson Jr. PhD Pamela B. MitchamJeanne D. Lestelle MS 《Journal of Equine Veterinary Science》2013
Two experiments were conducted to assess the repeatability of prolactin responses to a small dose of sulpiride in estrogen-primed geldings in spring and in mares during the estrous cycle in summer. Six long-term geldings each received a single intramuscular injection of 100 mg of estradiol cypionate on March 31, 2011, and were then challenged with an intravenous injection of dl-sulpiride (5 μg/kg of body weight of the racemic mixture) every other day for a total of 8 days. Jugular blood was collected at 0, 10, 20, 40, and 60 minutes after the injection of sulpiride for prolactin measurement. The experiment was repeated with six mares during the summer (July), except that the number of challenges was extended to 15 over 30 days so that any effect of estrous cycle stage could be assessed. Prolactin responses in geldings during April were robust and were varied in a quadratic manner (P < .003) over the eight sulpiride injections, increasing linearly to a plateau by the fourth injection. Mares also displayed robust prolactin responses to sulpiride injections in July, and there was no effect (P > .1) of day of injection and no effect of stage of estrous cycle (follicular phase, early diestrus, or late diestrus). We concluded that prolactin responses to this dose of sulpiride were sufficiently robust and repeatable for use as a paradigm for studies of the relative competitive efficacy and duration of action of various dopaminergic compounds and their vehicular formulations. 相似文献
995.
996.
K Sirisha NL Selokar M Saini P Palta RS Manik MS Chauhan SK Singla 《Reproduction in domestic animals》2013,48(4):538-544
This study was carried out to compare the post‐thaw cryosurvival rate and the level of apoptosis in vitro produced zona‐free cloned buffalo blastocysts subjected to slow freezing or vitrification in open‐pulled straws (OPS). Zona‐free cloned embryos produced by handmade cloning were divided into two groups and were cryopreserved either by slow freezing or by vitrification in OPS. Cryosurvival of blastocysts was determined by their re‐expansion rate following post‐thaw culture for 22–24 h. The post‐thaw re‐expansion rate was significantly (p < 0.05) higher following vitrification in OPS (71.2 ± 2.3%) compared with that after slow freezing (41.6 ± 4.8%). For examining embryo quality, the level of apoptosis in day 8 frozen‐thawed blastocysts was determined by TUNEL staining. The total cell number was not significantly different among the control non‐cryopreserved cloned embryos (422.6 ± 67.8) and those cryopreserved by slow freezing (376.4 ± 29.3) or vitrification in OPS (422.8 ± 36.2). However, the apoptotic index, which was similar for embryos subjected to slow freezing (14.8 ± 2.0) or OPS vitrification (13.3 ± 1.8), was significantly (p < 0.05) higher than that for the control non‐cryopreserved cloned embryos (3.4 ± 0.6). In conclusion, the results of this study demonstrate that vitrification in OPS is better than slow freezing for the cryopreservation of zona‐free cloned buffalo blastocysts because it offers a much higher cryosurvival rate. 相似文献
997.
A Yadav KP Singh MK Singh N Saini P Palta RS Manik SK Singla RC Upadhyay MS Chauhan 《Reproduction in domestic animals》2013,48(5):858-865
For investigating the effects of physiologically relevant heat shock, buffalo oocytes/embryos were cultured at 38.5°C (control) or were exposed to 39.5°C (Group II) or 40.5°C (Group III) for 2 h once every day throughout in vitro maturation (IVM), fertilization (IVF) and culture (IVC). Percentage of oocytes that developed to 8‐cell, 16‐cell or blastocyst stage was lower (p < 0.05) and the number of apoptotic nuclei was higher (p < 0.05) for Group III > Group II > controls. At both 8–16‐cell and blastocyst stages, relative mRNA abundance of stress‐related genes HSP 70.1 and HSP 70.2 and pro‐apoptotic genes CASPASE‐3, BID and BAX was higher (p < 0.05) in Groups III and II than that in controls with the exception of stress‐related gene HSF1. Expression level of anti‐apoptotic genes BCL‐XL and MCL‐1 was also higher (p < 0.05) in Groups III and II than that in controls at both 8–16‐cell and blastocyst stages. Among the genes related to embryonic development, at 8–16‐cell stage, the expression level of GDF9 was higher (p < 0.05) in Group III than that in controls, whereas that of GLUT1, ZAR1 and BMP15 was not significantly different among the three groups. At the blastocyst stage, relative mRNA abundance of GLUT1 and GDF9 was higher (p < 0.05) in Group II than that in controls, whereas that of ZAR‐1 and BMP15 was not affected. The results of this study demonstrate that exposure of buffalo oocytes and embryos to elevated temperatures for duration of time that is physiologically relevant severely compromises their developmental competence, increases apoptosis and affects stress‐, apoptosis‐ and development‐related genes. 相似文献
998.
MK Singh KP Singh D Kumar RA Shah T Anand MS Chauhan RS Manik SK Singla P Palta 《Reproduction in domestic animals》2013,48(2):284-291
When buffalo embryonic stem (ES) cell–like cells that expressed surface markers SSEA‐4, TRA‐1‐60, TRA‐1‐81, CD9 and CD90 and intracellular markers OCT4, SOX2 and FOXD3, as shown by immunofluorescence, and that expressed REX‐1 and NUCLEOSTEMIN as confirmed by RT‐PCR, were subjected to suspension culture in hanging drops in absence of LIF and buffalo foetal fibroblast feeder layer support, they differentiated to form three‐dimensional embryoid bodies (EBs). Of 231 EBs examined on Day 3 of suspension culture, 141 (61.3 ± 3.09%) were of compact type, whereas 90 (38.4 ± 3.12%) were of cystic type. The cells obtained from EBs were found to express NF‐68 and NESTIN (ectodermal lineage), BMP‐4 and α‐skeletal actin (mesodermal lineage), and α‐fetoprotein, GATA‐4 and HNF‐4 (endodermal lineage). When these EBs were cultured on gelatin‐coated dishes, they spontaneously differentiated to several cell types such as epithelial‐ and neuron‐like cells. When EBs were cultured in the presence of 1 or 2% DMSO or 10?8 m or 10?7 m retinoic acid for 25 days, ES cells could be directed to form muscle cell–like cells, the identity of which was confirmed by expression of α‐actinin by immunofluorescence and of MYF‐5, MYOD and MYOGENIN genes by RT‐PCR. MYOD was first detected on Day 10 in both treatment groups and on Day 15 in controls, whereas MYOGENIN was first detected on Day 10, Day 15 and Day 25 in the presence of retinoic acid, in the presence of DMSO and in controls, respectively. The present study demonstrates the ability of buffalo ES cell–like cells to undergo directed differentiation to cells of skeletal myogenic lineage. 相似文献
999.