全文获取类型
收费全文 | 1825篇 |
免费 | 67篇 |
国内免费 | 80篇 |
专业分类
林业 | 42篇 |
农学 | 173篇 |
基础科学 | 94篇 |
179篇 | |
综合类 | 1089篇 |
农作物 | 104篇 |
水产渔业 | 77篇 |
畜牧兽医 | 168篇 |
园艺 | 28篇 |
植物保护 | 18篇 |
出版年
2024年 | 7篇 |
2023年 | 18篇 |
2022年 | 58篇 |
2021年 | 48篇 |
2020年 | 43篇 |
2019年 | 46篇 |
2018年 | 17篇 |
2017年 | 70篇 |
2016年 | 72篇 |
2015年 | 105篇 |
2014年 | 118篇 |
2013年 | 125篇 |
2012年 | 151篇 |
2011年 | 151篇 |
2010年 | 115篇 |
2009年 | 135篇 |
2008年 | 108篇 |
2007年 | 98篇 |
2006年 | 85篇 |
2005年 | 67篇 |
2004年 | 37篇 |
2003年 | 55篇 |
2002年 | 26篇 |
2001年 | 23篇 |
2000年 | 23篇 |
1999年 | 26篇 |
1998年 | 16篇 |
1997年 | 19篇 |
1996年 | 20篇 |
1995年 | 18篇 |
1994年 | 17篇 |
1993年 | 13篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1990年 | 9篇 |
1989年 | 4篇 |
1988年 | 7篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
排序方式: 共有1972条查询结果,搜索用时 147 毫秒
201.
[目的]考察金属离子对芋艿分离蛋白食品功能性质的影响。[方法]以芋艿为原料,提取分离蛋白,研究了盐离子种类及强度对芋艿分离蛋白流变特性、起泡性、泡沫稳定性和乳化性及乳化稳定性的影响。[结果]试验表明,盐种类及其浓度对芋艿分离蛋白的食品功能特性有明显的影响。在物质的量浓度为0~0.6%范围内,K+和Na+浓度增加能促进芋艿分离蛋白溶解,降低起泡性和起泡稳定性,增加乳化性和乳化稳定性,在0~0.8%范围内,能降低表观黏度、滞后现象、Tgel和凝胶G';当K+和Na+浓度继续增加时,蛋白溶解度降低,起泡性增加,起泡稳定性、乳化性和乳化稳定性减小,表观黏度、滞后现象、Tgel和凝胶G'增加。Ca2+和Mg2+能在相邻多肽的特殊氨基酸残基之间形成交联,在离子浓度小于0.4%时,强度强于离子效应,使蛋白质溶液起泡性增加,但其他功能特性与K+和Na+相似。[结论]研究有助于加深对芋艿的了解,拓展芋艿食品的应用范围,且试验数据可为芋艿蛋白质食品生产提供参考依据。 相似文献
202.
203.
204.
张和平 《内蒙古农业大学学报(自然科学版)》1991,(2)
本研制以小麦粉,莜麦粉、牛乳、骨肉泥、蔗糖为主要原料,根据断乳期婴儿的营养需要、强化了V_A、V_(B1)、V_(B2)、V_C、V_E、叶酸、烟酸以及铁和锌,经适当的配合,研制出了婴儿断乳期食品奶麦粉(1)和奶麦粉(2)。其中蛋白质含量大于40%,热能大于350kcal/100g,其它各项营养成份和卫生指标基本上达到了中华人民共和国GB—869—83婴儿断乳食品营养及卫生标准和FAO/WHO74—1976所推荐的婴儿食品标准,可作为婴儿断乳期的辅助食品和婴幼儿进入普通食品的过渡食品。其中蛋白质中必需氨基酸含量接近WHO/FAO所推荐的理想模式,碳水化合物的组成成份更加适合婴儿的消化特点。 相似文献
205.
为全面衡量魁蚶的性腺发育,生殖腺指数ABC作如下定义:A=性腺长×性腺厚;B=A/软体部重;C=A/足高×体壁厚(×100%)。在15—25℃范围内,投饵240—320×10~6细胞/日×蚶的褐指藻都可以使魁蚶的性腺有较快的发育,而卵母细胞却需要高于200℃条件下才能成熟。在饵料不足情况下,魁蚶性腺退化。卵母细胞发育到110—130μ时达其最大值,而后,卵黄颗粒收缩,胚泡缩小,最后消失。至直径57μ左右时,卵母细胞达到完全成熟。小球藻,褐指藻,淀粉,大豆粉等饵科效果的比较研究表明,以1500×10~6细胞/日·蚶的小球藻混合以150×10~6细胞/日·蚶的褐指藻效果最佳,单独饲以小球藻,褐指藻及人工配合饵料也取得较好的效果。以豆粉为主的饲料导致性腺退化。 相似文献
206.
The toxicity and neurological effects of mirex, chlordecone, and four hydrogenated mirex analogs were evaluated on the American cockroach. The severity of poisoning symptoms correlated with the ability of each compound to increase spontaneous activity and prolong synaptic afterdischarge in ganglia of the ventral nerve cord. Afterdischarge across the metathoracic ganglion was consistent with a characteristic wing splaying symptom in mirex-poisoned cockroaches. The actions of hemicholinium-3 and nicotine on nerve cords from mirex-poisoned cockroaches are described and are consistent with a hypothesis that the increased spontaneous activity and afterdischarge are the result of enhanced transmitter release in ganglia of poisoned animals. 相似文献
207.
Ishida R Masuda K Kurata K Ohno K Tsujimoto H 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2004,18(1):25-30
Lymphocyte blastogenic responses against food allergens in dogs with food hypersensitivity were evaluated in this study. Eleven dogs with food hypersensitivity, based on food elimination and oral food provocation tests and allergic responses to food allergens, were examined by various tests such as intradermal testing, antigen-specific IgE testing, and lymphocyte blastogenic responses. The number and kinds of food allergens identified as positive by these tests were compared with the offending food allergens that were found in an oral food provocation test. In 9 (82%) of the 11 dogs with food hypersensitivity, there was close agreement for positive allergens between the results of lymphocyte blastogenic responses and oral food provocation test; however, there was little agreement for intradermal and IgE testing of the positive allergens with those of the oral food provocation test (11% and 31%, respectively). In the 9 dogs, the stimulation indices of lymphocyte blastogenic responses increased to 2.0-10.1 upon food provocation but decreased significantly to 0.7-1.4 upon feeding the elimination diet until clinical signs disappeared. These results indicate that lymphocyte blastogenic responses may fluctuate because of exposure to offending food allergens in dogs with food hypersensitivity. Lymphocytes reactive to food allergens may play an important role in the pathogenesis of food hypersensitivity in dogs. 相似文献
208.
Naylor JM Poirier KL Hamilton DL Dowling PM 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2006,20(6):1408-1413
The effect of changes in feed intake on auscultatable gastrointestinal sounds has not been systematically studied. Disagreement also is present in the literature about variation in sounds according to the quadrant of auscultation. Gastrointestinal sounds were recorded over the center of the left dorsal, left ventral, right ventral, and right dorsal quadrants and over the middle of the right abdominal flank. During 24 hours (n = 4) or 48 hours (n = 5) of fasting, there was a reduction in the intensity of gastrointestinal sounds as assessed by analysis of sound recordings. There was also a reduction in the number of mixing-like and propulsive-like sounds heard by 2 blinded observers. After refeeding, there was a marked increase in sound. Sound intensity varied among abdominal quadrants, but blinded observers did not notice significant differences in the number of mixing-like sounds. The left dorsal quadrant was quieter than others during fasting and refeeding. The right ventral quadrant appeared to be least affected by fasting, and sounds were louder over the right ventral and right middle quadrants than over the others. The blinded observers' perceptions of sound correlated poorly with one another and with objective measures of sound intensity. This experiment demonstrates the effectiveness of computerized analysis of abdominal sound in detecting a reduction in the intensity of gastrointestinal sounds during fasting and their return during refeeding. The left dorsal quadrant was quieter than other quadrants, likely because of its position over the small colon. There was considerable observer variation in the number of intestinal sounds heard. 相似文献
209.
210.
以项目式教学为总体思路,从课程定位、课程目标、课程内容、课程实施、效果评价和课程建设等方面,对乳制品加工技术课程体系的改革进行了探索。实践表明,改革后的教学体系可使学生在有限的时间内对该学科形成较为清晰的理解和把握,课程的教学效果有了明显的提高。 相似文献