全文获取类型
收费全文 | 234篇 |
免费 | 25篇 |
专业分类
林业 | 12篇 |
农学 | 18篇 |
基础科学 | 2篇 |
34篇 | |
综合类 | 10篇 |
农作物 | 19篇 |
水产渔业 | 20篇 |
畜牧兽医 | 110篇 |
园艺 | 7篇 |
植物保护 | 27篇 |
出版年
2022年 | 7篇 |
2021年 | 10篇 |
2020年 | 14篇 |
2019年 | 22篇 |
2018年 | 16篇 |
2017年 | 16篇 |
2016年 | 12篇 |
2015年 | 12篇 |
2014年 | 12篇 |
2013年 | 13篇 |
2012年 | 14篇 |
2011年 | 12篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 7篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 1篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1985年 | 4篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有259条查询结果,搜索用时 78 毫秒
41.
Heart development requires coordinated activity of various factors, the disturbance of which can lead to congenital heart defects. Heart lectin‐associated matrix protein‐1 (hLAMP‐1) is a matrix protein expressed within Hensen's node at Hamburger–Hamilton (HH) stage 4, in the lateral mesoderm by HH stages 5–6 and enhanced within the left pre‐cardiac field at HH stage 7. At HH stages 15–16, hLAMP‐1 expression is observed in the atrioventricular canal and the outflow tract. Also, the role of hLAMP‐1 in induction of mesenchyme formation in chick heart has been well documented. To further elucidate the role of this molecule in heart development, we examined its expression patterns during HH stages 8–14 in the chick. In this regard, we immunostained sections of the heart during HH stages 8–14 with antibodies specific to hLAMP‐1. Our results showed prominent expression of hLAMP‐1‐positive particles in the extracellular matrix associated with the pre‐cardiac mesoderm, the endoderm, ectoderm as well as neuroectoderm at HH stages 8–9. After formation of the linear heart tube at HH stage 10, the expression of hLAMP‐1‐stained particles disappears in those regions of original contact between the endoderm and heart forming fields due to rupture of the dorsal mesocardium while their expression becomes confined to the arterial and venous poles of the heart tube. This expression pattern is maintained until HH stage 14. This expression pattern suggests that hLAMP‐1 may be involved in the formation of the endocardial tube. 相似文献
42.
Taia A. Abd El–Mageed Ahmed M.A. El-Sherif Mahmoud M. Ali Mohamed H. Abd El-Wahed 《Archives of Agronomy and Soil Science》2017,63(6):827-840
A 2-year field experiment (2013 and 2014) was conducted in calcareous soil (CaCO3 19.2%), on soybean grown under three irrigation regimes 100%, 85% and 70% of crop evapotranspiration combined with three potassium (K2O) levels (90, 120 and 150 kg ha?1). The objective was to investigate the complementary properties of potassium fertilizer in improving soybean physiological response under water deficit. Plant water status (relative water content RWC, chlorophyll fluorescence Fv/F0 and Fv/Fm), had been significantly affected by irrigation or/and potassium application. Potassium improved growth characteristics (i.e. shoot length, number, leaf area and dry weight of leaves) as well as physiochemical attributes (total soluble sugars, free proline and contents of N, P, K, Ca and Na). Yield and yield water use efficiency (Y-WUE) were significantly affected by irrigation and potassium treatments. Results indicated that potassium application of 150 and 120 kg ha?1 significantly increased seed yield by 29.6% and 13.89%, respectively, compared with 90 kg ha?1 as average for two seasons. It was concluded that application of higher levels of potassium fertilizer in arid environment improves plant water status as well as growth and yield of soybean under water stress. 相似文献
43.
Young-Mee Kim Jong-Kyung Lee A.M. Abd el-aty Sung-Hee Hwang Jae-Hoon Lee Sang-Mok Lee 《The Canadian veterinary journal. La revue veterinaire canadienne》2010,51(4):380-384
Dogs hospitalized in veterinary clinics are likely to show signs of separation-induced anxiety from hospitalization. The study assessed the effect of dog-appeasing pheromone (DAP) on 10 typical separation-related behavioral signs in hospitalized dogs. A DAP treated group (n = 24) was compared with a placebo control group (n = 19). There was overall amelioration of the signs without ‘vigilance’ and ‘anorexia’ in the DAP-treated dogs; marked decreases were noted in elimination (P = 0.038), excessive licking (P = 0.005), and pacing (P = 0.017). The results suggest that the use of DAP could decrease separation-induced anxiety, distress, and fear in inpatients, and possibly facilitate recovery in hospitalized dogs. 相似文献
44.
45.
Metwally Abd El-Alim A. Safina Sayed A. Abdel-Wahab Eman I. Abdel-Wahab Sherif I. Abdel-Wahab Tamer I. 《Journal of Crop Science and Biotechnology》2021,24(2):203-220
Journal of Crop Science and Biotechnology - Cropping systems are relatively more important for testing soybean genotypes under Egyptian conditions. A field experiment was carried out at the... 相似文献
46.
Azza A. S. Labib Somaia A. Abd El-Latife Helmy Omran 《Plant foods for human nutrition (Dordrecht, Netherlands)》1997,50(4):333-347
In this study, Jew's mallow and spinach were heat treated and kept frozen, at –18°C, for 3 months. Analysis of some chemical
components and enzymatic activities as well as a sensory evaluation were undertaken. At the end of the storage period, blanched
spinach showed no PPO (polyphenyloxidase) activity at all, but still contained PO (peroxydase) and LO (lipoxygenase) activities.
The untreated spinach stored under the same conditions showed high activities of PO, PPO and LO. The heat treated mallow still
contained high enzyme activities which decreased slowly during frozen storage. Statistical analysis of the chemical composition
and the sensory evaluation results indicated that heat treatments of mallow caused significant differences in total solids,
pH, chlorophylla and total chlorophyll, while frozen storage, of samples of the same treatment for 3 months caused no significant differences
in moisture, ash, oxalic acid, pH, chlorophylla and total chlorophyll. No significant differences could be noticed in the overall acceptability between mallow samples mixed
with hot water and those mixed in the overall acceptability between mallow samples mixed with hot water and those mixed with
a hot 0.1% MgCO3 solution. Significant differences were found between the heat treated and the untreated mallow. Changes of the chemical composition
and the overall acceptability of blanched spinach during frozen storage showed almost the same trend noticed for the Jew's
mallow. 相似文献
47.
Actions concerning animal health in turkey production are coming more and more to the fore. Litter quality has a great impact on the bird's health and welfare. This study aimed at evaluating the effects of using floor heating, different litter materials, and exposure to litter with a "critical moisture content" of 35% for 16 or 24 hr/day on the severity of foot pad dermatitis (FPD), a widespread disease in fattening turkeys. Four groups of 2-wk-old female turkeys, with 20 birds in each, were reared during 3 wk. All turkeys were fed a commercial pellet diet ad libitum. The first two groups were kept on wood shavings (35% moisture) without and with floor heating. The other two groups were housed on lignocellulose (Soft Cell) of 35% moisture without and with floor heating. In each group, half of the birds were housed for 8 hr/day in adjacent separate boxes where the litter was kept clean and dry throughout the experimental period. Foot pads were assessed weekly for external and at day 35 for histopathologic scoring (scores: 0 = healthy; 7 = ulcer). At day 14 each bird had normal and healthy foot pads. The results indicate that using floor heating resulted in significantly lower FPD scores (0.8 +/- 0.2) compared to groups without floor heating (2.0 +/- 0.8). Using lignocellulose as a litter material resulted in significantly lower histopathologic FPD scores (1.4 +/- 0.7) compared with wood shavings (1.7 +/- 0.8). In all birds housed on dry litter for 8 hr/day, significantly lower FPD scores were found compared to birds housed on wet litter for 24 hr. In conclusion, using floor heating, even with wet litter (35% moisture), independent of the litter type, resulted in reduced severity of FPD compared to those birds housed in pens without using floor heating. Additionally, using lignocellulose as a litter material resulted in lower FPD compared with wood shavings. Keeping litter dry and "warm" could be achieved by using floor heating, which is considered a practical step to enhance animal health and welfare. 相似文献
48.
El-Baky HA Linke D Nimtz M Berger RG 《Journal of agricultural and food chemistry》2011,59(18):10311-10316
The first enzyme of the basidiomycete Piptoporus soloniensis, a peptidase (PsoP1), was characterized after isolation from submerged cultures, purification by fractional precipitation, and preparative native-polyarylamide gel electrophoresis (PAGE). The native molecular mass of PsoP1 was 38 kDa with an isoelectric point of 3.9. Similar to chymosin from milk calves, PsoP1 showed a maximum milk-clotting activity (MCA) at 35-40 °C and was most stable at pH 6 and below 40 °C. The complete inhibition by pepstatin A identified this enzyme as an aspartic peptidase. Electrospray ionization-tandem MS showed an amino acid partial sequence that was more homologous to mammalian milk clotting peptidases than to the chymosin substitute from a fungal species, such as the Zygomycete Mucor miehei. According to sodium dodecyl sulfate-PAGE patterns, the peptidase cleaved κ-casein in a way similar to chymosin and hydrolyzed β-casein slowly, as it would be expected from an efficient chymosin substitute. 相似文献
49.
El-Gindy Yassmine Zeweil Hassan Zahran Soliman El-Rahman Mohamed Abd Eisa Fawzi 《Tropical animal health and production》2020,52(3):999-1004
Tropical Animal Health and Production - It is known that using antibiotics by way of growth promoters has harmful side effects on both animals and consumer health due to cross-resistance among... 相似文献
50.
Three‐week‐old nodulated faba bean plants were subjected to two levels of water stress (0.5 and 0.25 field capacity; soil water content of 20 and 10%) for five weeks. Half of the stressed plants was treated with potassium chloride (KC1) at 10 (K1) and 150 mg (K2)/kg soil at the beginning of water deficit. Nodulation was examined and some nodule activities were assayed. Nodulation, nitrogenase activity, total nitrogen (N), and dry matter yield were significantly decreased by increasing stress but were significantly higher with the two levels of potassium (K) supply. Leghaemoglobin and protein contents of cytosol as well as nodule protease and invertase were severely depressed by drought stress. Soluble carbohydrate contents of nodules, however, was significantly increased. Protein and leghaemoglobin contents and enzyme activities were greater with K fertilization but less soluble carbohydrate was accumulated. The results indicate that K supply, particularly at the 150 mg/kg soil level, increased faba bean resistance to water stress. 相似文献