全文获取类型
收费全文 | 1258篇 |
免费 | 56篇 |
专业分类
林业 | 128篇 |
农学 | 47篇 |
基础科学 | 1篇 |
182篇 | |
综合类 | 46篇 |
农作物 | 54篇 |
水产渔业 | 112篇 |
畜牧兽医 | 645篇 |
园艺 | 10篇 |
植物保护 | 89篇 |
出版年
2023年 | 4篇 |
2022年 | 16篇 |
2021年 | 33篇 |
2020年 | 20篇 |
2019年 | 15篇 |
2018年 | 24篇 |
2017年 | 31篇 |
2016年 | 38篇 |
2015年 | 43篇 |
2014年 | 57篇 |
2013年 | 106篇 |
2012年 | 80篇 |
2011年 | 96篇 |
2010年 | 43篇 |
2009年 | 52篇 |
2008年 | 76篇 |
2007年 | 88篇 |
2006年 | 84篇 |
2005年 | 82篇 |
2004年 | 86篇 |
2003年 | 72篇 |
2002年 | 44篇 |
2001年 | 34篇 |
2000年 | 21篇 |
1999年 | 14篇 |
1998年 | 8篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1978年 | 1篇 |
1972年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有1314条查询结果,搜索用时 15 毫秒
71.
72.
73.
Iwata K Kinoshita M Susaki N Uenoyama Y Tsukamura H Maeda K 《The Journal of reproduction and development》2011,57(3):379-384
Ketosis is found in various pathophysiological conditions, including diabetes and starvation, that are accompanied by suppression of gonadal activity. The aim of the present study was to determine the role of ketone body in the brain in regulating pulsatile luteinizing hormone (LH) secretion in female rats. Injection of 3-hydroxybutyrate (3HB), a ketone body, into the fourth cerebroventricle (4V) induced suppression of pulsatile LH secretion in a dose-dependent manner in ovariectomized (OVX) rats with an estradiol (E2) implant producing diestrus plasma E2 levels. Plasma glucose and corticosterone levels increased immediately after the 4V 3HB injection, suggesting that the treatment caused a hunger response. The 3HB-induced suppression of LH pulses might be mediated by noradrenergic inputs to the hypothalamic paraventricular nucleus (PVN) because a local injection of α-methyl- p-tyrosine, a catecholamine synthesis inhibitor, into the PVN blocked 3HB-induced suppression of LH pulses and PVN noradrenaline release was increased by 4V 3HB injection in E2-primed OVX rats. These results suggest that ketone body sensed by a central energy sensor in the hindbrain may suppress gonadotropin release via noradrenergic inputs to the PVN under ketosis. 相似文献
74.
Naoya Yamaguchi Takashi Sayama Hiroyuki Yamazaki Tomoaki Miyoshi Masao Ishimoto Hideyuki Funatsuki 《Breeding Science》2014,64(4):300-308
Lodging tolerance (LT) is an important trait for high yield and combine-harvesting efficiency in soybean [Glycine max (L.) Merr.]. Many previous studies have investigated quantitative trait loci (QTLs) for lodging score (LS) in soybean. Most of the investigated QTLs were located in the proximal region of maturity or growth habit loci. The aim of this study was to identify genetic factors for LT not associated with maturity or growth habit. QTL analysis was performed using a recombinant inbred line (RIL) population derived from a cross between ‘Toyoharuka’ (TH), a lodging-tolerant cultivar, and ‘Toyomusume’ (TM). The genotypes of TH and TM were estimated as both e1e2E3E4 and dt1. The average LS over 4 years was used for QTL analysis, identifying a major and stable QTL, qLS19-1, on chromosome 19. The LS of the near-isogenic line (NIL) with the TH allele at Sat_099, the nearest marker to qLS19-1, was significantly lower than the NIL with the TM allele at that position. The TH allele at Sat_099 rarely had a negative influence on seed yield or other agronomic traits in both NILs and the TM-backcrossed lines. Our results suggest that marker-assisted selection for qLS19-1 is effective for improving LT in breeding programs. 相似文献
75.
76.
77.
Compressive deformation of wood impregnated with low molecular weight phenol formaldehyde (PF) resin II: effects of processing parameters 总被引:1,自引:0,他引:1
To obtain high-strength phenol formaldehyde (PF) resin-impregnated compressed wood at low pressing pressure, the effects of resin content, preheating temperature, pressing temperature, and pressing speed on the compressive deformation of oven-dried low molecular weight PF resin-impregnated wood was investigated. With an increase of PF resin content, the Youngs modulus of the cell wall perpendicular to the fiber direction decreases, and collapse-initiating pressure decreases linearly with the Youngs modulus. This indicates that the occurrence of cell wall collapse is strain-dependent. By increasing preheating temperatures, the collapse-initiating pressure increases due to the increment of the Youngs modulus of the cell wall. An increase in pressing temperature results in the thermal softening of the cell wall and causes collapse at a lower pressure. The wood is compressed effectively despite accelerated resin curing. The pressing speed significantly affects the viscoelastic deformation of the cell wall and the wood is well deformed with decreasing pressing speed, although the differences in density and mechanical properties are relatively small after a pressure-holding period of 30min. In all the parameters examined in this study, the Youngs modulus and bending strength increase with increasing density. 相似文献
78.
Takeuchi Y Matsuura S Fujino Y Nakajima M Takahashi M Nakashima K Sakai Y Uetsuka K Ohno K Nakayama H Tsujimoto H 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2008,70(10):1085-1089
Two cats showing chronic vomiting, diarrhea and weight loss were found to have leukocytosis with marked eosinophilia. Both cats were diagnosed with hypereosinophilic syndrome by the findings of increased eosinophils and their precursors in the bone marrow, eosinophilic infiltration into multiple organs, and exclusion of other causes for eosinophilia. Although cytoreductive chemotherapy with hydroxycarbamide and prednisolone was performed, these two cats died 48 days and 91 days after the initial presentation. 相似文献
79.
Evaluation of three hormonal protocols for anovulatory lactating cows under regulations restricting the use of estrogenic compounds 下载免费PDF全文
Guang‐Min Yu Yue Wu Xian‐Long Wang Shuan Zhao Teruo Maeda Shen‐Ming Zeng 《Animal Science Journal》2018,89(4):640-647
When European Union regulations restricted the use of estrogenic compounds in food‐producing animals, refined hormonal protocols were no longer applicable for anovulatory cows. However, Ovsynch and its adaptations are routinely and uniformly applied to all cows regardless of ovarian function. To evaluate their efficacy on anovulatory cows, 143, 147 and 144 anovulatory cows received Ovsynch, Presynch and G6G protocols, respectively. In comparison, 150 cyclic cows were bred without using a synchronized protocol. Results showed that cows in the Presynch group had luteolysis responding to the last prostaglandin F2α (PGF2α) injection greater than the Ovsynch group. The serous progesterone levels at the first gonadotropin‐releasing hormone of Ovsych and the last PGF2α injection was greater in the G6G group than the other two hormonal treatment groups. Concentrations of Ca2+ and total protein in cervical mucus in all three hormone‐treated groups before artificial insemination (AI) were significantly different from the controls. The G6G group obtained a greater pregnancy rate compared with Ovsynch and Presynch, but significantly less than the controls. For open cows in the Ovsynch group, estrus rate within 24 days after the first AI was significantly less than the controls. In conclusion, the G6G treatment resulted to better reproductive performance in anovulatory cows. 相似文献
80.