全文获取类型
收费全文 | 546篇 |
免费 | 34篇 |
国内免费 | 14篇 |
专业分类
林业 | 42篇 |
农学 | 27篇 |
基础科学 | 8篇 |
88篇 | |
综合类 | 122篇 |
农作物 | 31篇 |
水产渔业 | 17篇 |
畜牧兽医 | 207篇 |
园艺 | 22篇 |
植物保护 | 30篇 |
出版年
2024年 | 3篇 |
2022年 | 11篇 |
2021年 | 14篇 |
2020年 | 8篇 |
2019年 | 14篇 |
2018年 | 12篇 |
2017年 | 19篇 |
2016年 | 18篇 |
2015年 | 12篇 |
2014年 | 24篇 |
2013年 | 35篇 |
2012年 | 23篇 |
2011年 | 42篇 |
2010年 | 35篇 |
2009年 | 46篇 |
2008年 | 29篇 |
2007年 | 24篇 |
2006年 | 17篇 |
2005年 | 25篇 |
2004年 | 22篇 |
2003年 | 12篇 |
2002年 | 13篇 |
2001年 | 15篇 |
2000年 | 10篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 5篇 |
1968年 | 2篇 |
1967年 | 3篇 |
1966年 | 4篇 |
排序方式: 共有594条查询结果,搜索用时 15 毫秒
51.
Two greenhouse experiments were conducted to evaluate the performance of selected soybean- Bradyrhizobium combinations in a soil having low P-high aluminum stresses under controlled conditions. Growth parameters such as plant height, nodule numbers, dry weight, nitrogenase activity and seed yield were used as an index. Three selected acid (low P-high Al) tolerant ( Essex, Tracy and Bedford ) and three sensitive ( Peking, Hill and McNair 600 ) soybean ( Glycine max ) varieties were sown in each pot. Three of the most tolerant strains of Bradyrhizobium (USDA 6, 110, 122), a mixture of these strains, and a commercial inoculant (Nitragin) were used to inoculate the Hartselle sandy loam soil. The results indicated that soil acidity significantly affected the soybean Bradyrhizobium symbiosis. The combination of variety Tracy plus Nitragin (mixed-strain) produced the highest and variety Peking plus mix-strain Nitragin the lowest plant height at all pH levels. Plants inoculated with Nitragin had higher shoot dry weight and seed yields. Variety Essex in combination with Nitragin produced the highest seed yields at all pH levels. Plants inoculated with Nitragin developed significantly more nodules than the other strains except for variety Peking. There was no significant difference in total nodule numbers between tolerant and sensitive soybean varieties at all soil pH levels except for Nitragin. Shoot total N did not increase by increasing the pH level or by using different variety-strain combinations. 相似文献
52.
A G Patel R B Patel M R Patel 《Journal of the Association of Official Analytical Chemists》1990,73(6):893-895
A liquid chromatographic (LC) method has been developed for determination of clobetasone-17-butyrate in ointment using clobetasone propionate as an internal standard. Separation was carried out on a C18 reverse-phase column using water-methanol as a mobile phase. Methylparaben and propylparaben (both sodium salt) used as preservatives did not interfere with separation. Compounds are detected photometrically at 235 nm. Mean assay results for 0.05% commercial ointments were 100.36% (n = 5). Mean recovery of clobetasone-17-butyrate added to commercial ointment was 99.89%. 相似文献
53.
54.
Most of the fruits formed on muskmelon go to waste due to premature shedding, insect punctures and rotting. An experiment was conducted to test the value of controlling insect damage, eliminating contact of fruits with the soil, avoiding continuous contact of the same part of fruits with the soil, and prophylactic application of fungicides on and around fruits, in saving the fruits from rotting. Placing of fruits on polyethylene sheets was best in reducing the incidence of fruit rot, increasing the yield, and providing high net income. Spraying Bordeaux mixture (6:3:100) on and around the fruits was next best. 相似文献
55.
Fluorescent antibody test for rapid diagnosis of coronaviral enteritis of turkeys (bluecomb). 总被引:2,自引:0,他引:2
Intestinal tissues obtained from coronavirus-infected embryos and turkeys were examined by fluorescent antibody tissue section technique (FAT). Evidence of viral antigen was demonstrated in the cytoplasm of the intestinal epithelial cells covering the villi. Embryo intestines that were examined from 24 to 96 hours after inoculation were positive for immunofluorescence (IF), whereas bursa of Fabricius was negative. Poults hatched from infected embryos were examined at 2 days of age and were positive for IF. Coronaviral antigen was detected by FAT in the cytoplasm of intestinal epithelial cells of the jejunum, ileum, duodenum, and cecum in all turkeys that were examined from 24 hours to 28 days. 相似文献
56.
In our experience, altrenogest has not always been able to exert predictable control over the estrous cycle of the mare. Therefore, we examined 12 mares that were treated with altrenogest to identify reasons for its failure to control the estrous cycle. The mares were fed altrenogest for 15 to 20 days and were examined for follicle development, ovulation, and corpus luteum formation during treatment. Through the use of real-time ultrasonography and radioimmunoassay for progesterone, we concluded that altrenogest was unable to suppress the growth of follicles to preovulatory size in some mares, leading to ovulation during treatment or earlier than expected after the end of treatment. In addition, altrenogest did not appear to shorten the life-spans of the corpora lutea that were formed during treatment; in 4 mares, this resulted in the persistence of corpora lutea after the end of the suggested 15-day periods of treatment. The latter findings led us to suggest that if a luteolytic dose of prostaglandin had been given at the end of altrenogest treatment, there would have been improved control over the estrous cycle. The results of our study confirmed our clinical impressions that altrenogest may be satisfactory to control the equine estrous cycle under some circumstances, but it should not be used when precise control over ovulation is required. 相似文献
57.
58.
59.
60.