全文获取类型
收费全文 | 726篇 |
免费 | 27篇 |
国内免费 | 2篇 |
专业分类
林业 | 49篇 |
农学 | 56篇 |
208篇 | |
综合类 | 49篇 |
农作物 | 97篇 |
水产渔业 | 25篇 |
畜牧兽医 | 212篇 |
园艺 | 11篇 |
植物保护 | 48篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 14篇 |
2020年 | 13篇 |
2019年 | 17篇 |
2018年 | 21篇 |
2017年 | 16篇 |
2016年 | 15篇 |
2015年 | 23篇 |
2014年 | 29篇 |
2013年 | 35篇 |
2012年 | 54篇 |
2011年 | 50篇 |
2010年 | 26篇 |
2009年 | 28篇 |
2008年 | 52篇 |
2007年 | 49篇 |
2006年 | 39篇 |
2005年 | 31篇 |
2004年 | 24篇 |
2003年 | 29篇 |
2002年 | 32篇 |
2001年 | 26篇 |
2000年 | 17篇 |
1999年 | 17篇 |
1998年 | 6篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 2篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1983年 | 2篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 4篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1965年 | 2篇 |
1964年 | 2篇 |
1963年 | 3篇 |
排序方式: 共有755条查询结果,搜索用时 15 毫秒
21.
22.
Flow cytometric assessment of ethylene glycol monoethyl ether on spermatogenesis in rats 总被引:1,自引:0,他引:1
Yoon CY Hong CM Cho YY Chung YH Min HK Yun YW Lee BJ Yang KH Lee YS Kim CK 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(2):207-212
The effects of ethylene glycol monoethyl ether (EGEE) on testicular cell populations in rats were investigated by a flow cytometric method. Rats were administered by gavage with EGEE at the various doses of 0 (saline alone), 100, 200, 400, and 800 mg/kg body weight/day for 4 weeks. The treatment of EGEE caused decreases in the weight of testis and epididymis and in the number of testicular cells. Histopathologically, exfoliation of germ cells into the tubular lumen was observed at the doses of above 200 mg/kg. The treatment of EGEE at the dose of 400 mg/kg caused moderate testicular degeneration. A significant depletion of haploid cells and a disproportionate ratio of diploid and tetraploid cells were observed as determined by flow cytometric analysis. These results indicate that the toxic effect of EGEE on the male reproductive system may be strongly associated with the disproportion of testicular germ cells. 相似文献
23.
Choi H Won S Chung W Lee K Chang D Lee H Eom K Lee Y Yoon J 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(2):158-162
Some studies have shown that relative to baseline, the renal resistive index (RI) remains unchanged in nonobstructed kidneys and increases in obstructed kidneys after administration of furosemide. To our knowledge, the effect of mannitol administration on the renal RI of dogs has not been reported. We evaluated the renal RI in 16 kidneys in 8 young adult dogs after administration of mannitol. The mean RI decreased significantly from baseline (P < .01). Additionally, left complete ureteral obstruction wasinduced in 5 dogs. Evaluation by Doppler ultrasonography was performed for 5 days. On the 5th day, Doppler examination was repeated at 30 and 60 minutes after administration of mannitol to obstructed dogs. After induction of left ureteral obstruction, the RI of the left kidney increased significantly over 5 consecutive days. Administration of mannitol decreased the RI in the nonobstructed contralateral kidneys, and thus the RI difference between obstructed and nonobstructed kidneys was increased above normal (P < .001). In conclusion, administration of mannitol may be useful as another diuretic agent to identify unilateral ureteral obstruction on Doppler sonographic examination. 相似文献
24.
25.
Won-Il Jeong Sun Hee Do Da-Hee Jeong Jae-Yong Chung Hai-Jie Yang Dong-Wei Yuan Il-Hwa Hong Jin-Kyu Park Moon-Jung Goo Kyu-Shik Jeong 《Journal of veterinary science (Suw?n-si, Korea)》2006,7(3):299-301
Three dead dogs were brought to the College of Veterinary Medicine, Kyungpook National University for study. Clinically, all the dogs showed emaciation, anorexia, depression, hemorrhagic vomiting and diarrhea for 7~10 days before death. All the clinical signs were first noted for about one month after feeding the dogs with commercial diets. At necropsy, all 3 dogs had severe renal damage with the same green-yellowish colored nephroliths in the renal pelvis. They also showed systemic hemorrhage and calcification of several organs, which might have been induced by uremia. Microscopically, necrosis, calcification and calculi were detected in the renal tubules, and especially in the proximal convoluted tubules and collecting ducts of the kidney. These findings were supportive of a mycotoxic effect, and especially on their kidneys. However, the precise cause of the toxic effect in these cases of canine renal failure could not be determined. 相似文献
26.
Stimulation of swine growth by porcine growth hormone 总被引:7,自引:0,他引:7
Highly purified porcine growth hormone (pGH; USDA-B1) was administered by im injection (22 micrograms X kg body weight-1 X d-1) to rapidly growing Yorkshire barrows for 30 d. Growth hormone significantly increased growth rate (10%), feed efficiency (4%), cartilage growth and muscle mass. However, pGH did not affect carcass adipose tissue mass. Intramuscular lipid content of the longissimus was increased 50% by pGH administration. Plasma pGH concentration was elevated (7- to 11-fold) for 3 to 5 h post-injection. Chronic administration of pGH depressed pituitary GH content and concentration approximately 45%. No GH antibodies were detected in the plasma of GH-treated swine. Plasma somatomedin-C concentration was increased 55% by GH treatment 3 h post-injection. Plasma glucose and insulin concentrations were both significantly increased in GH-treated swine, suggesting that the animals had developed a state of insulin resistance. Plasma-free fatty acid concentration tended to be higher in GH-treated animals. Treatment of swine with pGH significantly decreased plasma blood urea nitrogen. Assessment of animal health during the trial and postmortem indicated that pGH administration did not have any adverse effects. In summary, treatment of young, rapidly growing swine with pGH stimulated growth performance without affecting animal health or inducing the production of GH antibodies. 相似文献
27.
This study evaluated the protection effectiveness of alcohol-borne reagents for the green color of ma bamboo (Dendrocalamus latiflorus Munro) and moso bamboo (Phyllostachys pubescens Mazel). The results show that the types and concentrations of alcohol-borne reagents, the kinds of solvent, and the conditions
of treatment greatly affected the green color of these two bamboo species. Without alkali pretreatment, an excellent green
color protection (a* = −14.5) was obtained when the ma bamboo culms were treated with 0.5% methanol-borne copper chloride (CuCl2) at 60°C for 30 min. Similar results were also obtained when ma bamboo culms were treated with 0.5% methanol-borne copper
nitrate [Cu(NO3)2] at 60°C for 2 h (a* = −13.5). For moso bamboo, an attractive green color in the bamboo culms was achieved by treating the specimens with 1%
methanol-borne copper acetate [Cu(CH3COO)2] at 60°C for 30 min. The a* value of treated specimens was −13.3. In addition, results demonstrated that ultrasonic treatment was more effective on
green color protection than conventional water bath treatment. When moso bamboo was treated with 1% copper acetate at 60°C
in an ultrasonic bath for only 15 min, a remarkable green color with an a* value of −13.6 was obtained on the bamboo epidermis. 相似文献
28.
由于现有的电子商务应用开发方法十分复杂,开发费用也十分高昂,对许多企业来说,要高效地开发可靠的电子商务应用是一个重要的挑战。而Web服务由于具有更简单的面向服务的结构以及更低的开发费用,越来越受到人们的欢迎。本文提出一种服务组合框架,通过这种框架可以采用基于Web服务的方法开发业务集成应用。通过考察Web服务的结构模型和电子商务的结构模式,我们认为本文所提出的框架能够组合用于电子商务应用的规范化Web服务,并且比现有的方法更加高效和可靠。 相似文献
29.
From January 1999 to May 2001, we investigated seasonal variations in the photosynthetic capacity of Taiwan spruce (Picea morrisonicola Hay.) growing in the subalpine region of subtropical Taiwan (23 degrees 29' N, 120 degrees 53' E, 2600 m a.s.l.). Photosynthetic capacity (near light-saturated net photosynthetic rate, Pnsat, chlorophyll fluorescence (Fv/Fm) and soluble protein concentration of needles all increased from mid or late spring to early winter. Even when minimum air temperature of the measuring day dropped to near 0 degrees C, Pnsat remained at about 20% of the highest value observed in winter. There was a curvilinear relationship between Fv/Fm and the minimum or mean air temperature of the measuring day. The increase in Fv/Fm with temperature was slowed when the daily mean air temperature was above 7 degrees C, or the minimum air temperature was above 3 degrees C; however, when air temperatures dropped below these values, Fv/Fm varied sharply. Seasonal variations in Pnsat paralleled those in Fv/Fm and needle soluble protein concentration. In early or mid spring when air temperature and Fv/Fm increased, Pnsat and soluble protein concentration remained low. Multiple regression analysis showed that seasonal variations in Pnsat were affected by Fv/Fm, air temperature and needle soluble protein concentration, and the multiple regression equation could be used to estimate Pnsat in different seasons. We conclude that the decrease in photosynthetic capacity of Taiwan spruce in winter and its subsequent recovery in spring were mainly caused by photoinhibition and its reversal, and changes in needle soluble protein concentration. Another possible explanation for the delayed recovery of photosynthetic capacity in spring may be associated with the slow increase in needle soluble protein concentration. 相似文献
30.
The methanol extracts of five tropical plants, Baeckea frutescens, Glycyrrhiza glabra, Kaempferia pandurata, Physalis angulata and Quercus infectoria, exhibited potent antibacterial activity against the cariogenic bacterium Streptococcus mutans. In particular, G. glabra, K. pandurata and P. angulata conferred fast killing bactericidal effect against S. mutans in 2 min at 50 microg/ml of extract concentration. 相似文献