全文获取类型
收费全文 | 1600篇 |
免费 | 108篇 |
国内免费 | 122篇 |
专业分类
林业 | 43篇 |
农学 | 109篇 |
基础科学 | 23篇 |
273篇 | |
综合类 | 497篇 |
农作物 | 160篇 |
水产渔业 | 132篇 |
畜牧兽医 | 396篇 |
园艺 | 64篇 |
植物保护 | 133篇 |
出版年
2024年 | 12篇 |
2023年 | 33篇 |
2022年 | 73篇 |
2021年 | 59篇 |
2020年 | 77篇 |
2019年 | 79篇 |
2018年 | 58篇 |
2017年 | 92篇 |
2016年 | 86篇 |
2015年 | 68篇 |
2014年 | 83篇 |
2013年 | 130篇 |
2012年 | 155篇 |
2011年 | 95篇 |
2010年 | 69篇 |
2009年 | 75篇 |
2008年 | 69篇 |
2007年 | 76篇 |
2006年 | 43篇 |
2005年 | 49篇 |
2004年 | 46篇 |
2003年 | 37篇 |
2002年 | 29篇 |
2001年 | 30篇 |
2000年 | 32篇 |
1999年 | 17篇 |
1998年 | 14篇 |
1997年 | 19篇 |
1996年 | 13篇 |
1995年 | 18篇 |
1994年 | 8篇 |
1993年 | 15篇 |
1992年 | 8篇 |
1991年 | 10篇 |
1990年 | 4篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1980年 | 2篇 |
1976年 | 1篇 |
1956年 | 2篇 |
排序方式: 共有1830条查询结果,搜索用时 15 毫秒
11.
Shaun C. OGILVIE James M. ATARIA James WAIWAI James DOHERTY Aroha MILLER James G. ROSS Charles T. EASON 《Integrative zoology》2010,5(1):37-43
In New Zealand, the vertebrate pesticide sodium fluoroacetate (Compound 1080) is aerially applied in baits for control of the brush-tailed possum Trichosurus vulpecula (Kerr, 1792). Maori, the indigenous people of New Zealand, have raised concerns about 1080 impacts on culturally-important species. Here, we outline two steps taken to help Maori assess 1080 risk. First, field research was undertaken to determine if naturally-occurring plants utilized by a Maori community for food and medicine would take up 1080 from baits. Single baits were placed at the base of individual plants of two species, pikopiko (Asplenium bulbiferum) and karamuramu (Coprosma robusta). Plants were sampled at various times up to 56 days, and samples were analyzed for 1080 content. No 1080 was detected in any of the pikopiko samples, whereas 1080 was detected in karamuramu, at a maximum concentration of 5 ppb after seven days, and 2.5 ppb after 14 days. This concentration decreased to 0 at 28 days, indicating that 1080 was not persistent. The results of the present study suggest there is negligible risk of humans being poisoned by consuming plants that have taken up 1080 from baits. To allay community concerns that minute concentrations of 1080 might influence the medicinal properties of plants, it is suggested that a withholding period of 30 days after 1080 control operations could be adopted. Second, after further consultation we undertook a review of the scientific literature relating to 1080 impacts on additional non-target species of cultural importance to Maori. The information was presented on an interactive foodweb database that allowed the collection and presentation of a large volume of complex information about 1080 in a holistic and pictorial fashion. This database was presented to many Maori communities throughout New Zealand, and feedback was overwhelmingly positive. The database is likely to play a key role in informing these communities about 1080, and is seen as an important new tool to help these communities make their own risk assessments. 相似文献
12.
13.
14.
Yasushi Ohmachi Tomomi Imamura Mizuyo Ikeda Eriko Shishikura Eunjoo Kim Osamu Kurihara Kazuo Sakai 《Journal of toxicologic pathology》2015,28(2):65-71
To evaluate the effectiveness of sodium bicarbonate (SB) in removing uranium and protecting animals from uranium toxicity, we intramuscularly administered 1 mg/kg of uranyl nitrate to 8-wk-old male SD rats, and 20 min after administration of uranyl nitrate, the animals were given a single oral administration of SB at 0.1, 0.3 or 1 g/kg. The SB treatment at a dose of 0.3 g/kg or more raised the pH of the rats’ urine until 4 h after treatment, and it significantly reduced the uranium amounts in the kidneys at 1 day after treatment. In another experiment, rats were intramuscularly administered 1 mg/kg of uranyl nitrate, and 20 min later, the animals were treated with sodium bicarbonate (0.1 or 1 g/kg). The rats were autopsied at 1, 3 and 7 days after uranium treatment. High-dose SB resulted in a significant increase in urinary uranium excretion in the first 24 h and a reduction of uranium deposition in the kidneys and femurs, and it also significantly suppressed uranium-induced renal toxicity, as shown by both histopathology and clinical chemistry at 3 days after uranium treatment. Low-dose SB did not show such marked effects. Our findings demonstrated that the uranium decorporation effect of sodium bicarbonate was observed at the dosage showing urine alkalinization in rats and that decorporation effect of sodium bicarbonate might be beneficial if it is administered immediately after incorporation of soluble uranium. 相似文献
15.
为了解国产头孢噻呋钠的毒性,进行了小鼠的急性毒性及对鸡的亚慢性毒性试验。结果表明,小鼠肌肉注射头孢噻呋钠,LD50为1 673.02 mg/kg;鸡注射头孢噻呋钠21 d,未发现与药物相关的体征变化,各组间的体重变化无显著性差异;采食量、饮水量随鸡龄增加而增加,平行比较无显著性差异;各阶段鸡的RBC、WBC分类记数(中性粒细胞/N、碱性粒细胞/B、酸性粒细胞/E、大单核细胞/M、淋巴细胞/L)均在正常值范围内,各组间无显著性差异;各组间血清生化值BUN、GPT、ALB也无显著性差异;各组脏器无显著性差异,说明该药毒性较低。 相似文献
16.
A detection method of dexamethasone sodium phosphate in houttuynia injection,bupleurum injection,vitamin C injection,lincomycin hydrochloride injection,and asragulus polysacharin injection was established by UPLC-PDA.The Waters ACQUITY UPLC® BEH C18 column(2.1 mm×50 mm,1.7 μm) was used,the mobile phase consisted of 0.75% triethylamine phosphatic liquor/solution (pH 3.0)-methyl alcohol-acetonitrile(50:45:5),the flow rate was 0.3 mL/min,the column temperature had remained 25℃,photodiode array detector wavelength range was 190 to 400 nm,the recorded wavelength was 242 nm,the injection volume was 10 μL.The linear range of dexamethasone sodium phosphatel was 10.0 to 200.0 mg/L (R2=0.9999),the mean recovery and RSD for dexamethasone sodium phosphate in houttuynia injection,bupleurum injection,vitamin C injection,lincomycin hydrochloride injection and asragulus polysacharin injection were 97.54% and 1.14%,101.59% and 0.19%,100.92% and 0.92%,99.82% and 0.73%,100.08% and 0.62%,respectively.This method was accurate,easy and fast,it was suitable for detection of dexamethasone sodium phosphatein houttuynia injection and other four kinds of injections. 相似文献
17.
用350只1周龄的Arbor Acres(AA)商品肉公鸡进行试验,采用2×3+1试验设计,其中葡萄糖酸钠2个水平(0.2%),植酸酶3个水平(0.500、1000 U/kg),另有一满足NRC钙、磷需要的正常日粮,共7个处理,每个处理5个重复,每个重复10只鸡。研究玉米-豆粕型低磷日粮中添加葡萄糖酸钠和植酸酶对肉鸡磷利用的影响。试验期1~3周。结果表明,在低磷日粮中添加葡萄糖酸钠显著提高了肉鸡的钙(P=0.003)和磷(P<0.001)的表观存留率,降低了血清碱性磷酸酶活性(P=0.038);植酸酶提高了肉鸡的胫骨灰分重量(P<0.001)、钙(P=0.005)和磷(P<0.001)的表观存留率。在胫骨灰分重量(P=0.030)和磷表观存留率(P=0.008)上,葡萄糖酸钠和植酸酶存在互作。 相似文献
18.
硒对STZ诱发糖尿病大鼠骨密度影响的研究初报 总被引:1,自引:0,他引:1
比较了在低硒饲料的基础上补充不同形态硒对糖尿病大鼠骨密度的影响。健康SD大鼠 1 2 8只 ,体重 50~ 60 g,随机分为 4组 ,每组 32只 ,雌雄各半 ,其中Ⅰ组为低硒对照组 (饲料含硒量 0 0 37mg/kg) ;Ⅱ组为补充亚硒酸钠组 (饲料含硒量 0 3mg/kg) ;Ⅲ组为补充富硒麦芽组(饲料含硒量 0 3mg/kg) ;Ⅳ组为补充富硒酵母组 (饲料含硒量 0 3mg/kg)。Ⅱ、Ⅲ、Ⅳ组的饲料均是在Ⅰ组低硒饲料的基础上分别添加适量的亚硒酸钠、富硒麦芽、富硒酵母后配制而成。喂饲 5周后 ,Ⅰ、Ⅱ、Ⅲ、Ⅳ组用链脲佐菌素 (streptozotocin ,STZ)按 60mg/kg腹腔注射诱发糖尿病 ,继续饲喂 6周。用单光子吸收法测定各组大鼠的肱骨、股骨、胫骨、桡骨的骨密度。结果表明 :①STZ致糖尿病大鼠的骨密度随时间的延长有逐渐下降的趋势。Ⅱ、Ⅲ、Ⅳ补硒组大鼠可以在一定时间内延缓STZ致糖尿病大鼠的骨密度下降。在此期间骨密度的下降以肱骨出现最早 ,股骨次之 ,桡骨、胫骨再次之。②饲料补硒组糖尿病大鼠的肱骨、股骨中硒的含量较饲料低硒组糖尿病大鼠的肱骨、股骨中硒的含量显著提高。③补充硒的形态 ,即有机硒 (富硒麦芽、富硒酵母 )或无机硒 (亚硒酸钠 )对糖尿病大鼠肱骨、股骨、胫骨、桡骨的骨密度影响差异不显著。 相似文献
19.
本试验建立了鱼腥草、柴胡、维生素C、盐酸林可霉素、黄芪多糖等注射液中非法添加地塞米松磷酸钠的超高效液相色谱检查方法。采用Waters ACQUITY UPLC® BEH C18色谱柱(2.1 mm×50 mm,1.7 μm),以0.75%三乙胺溶液(磷酸调节pH 3.0)-甲醇-乙腈(50:45:5)为流动相,流速0.3 mL/min,二极管阵列检测器,波长采集范围为190~400 nm,记录色谱图波长242 nm,柱温25℃,进样量10 μL。地塞米松磷酸钠质量浓度在10.0~200.0 mg/L内峰面积呈良好线性关系(R2=0.9999),在鱼腥草、柴胡、维生素C、盐酸林可霉素、黄芪多糖等注射液中地塞米松磷酸钠的平均回收率和相对标准偏差(RSD)分别为97.54%和1.14%、101.59%和0.19%、100.92%和0.92%、99.82%和0.73%、100.08%和0.62%。本方法简单、快速、灵敏、可靠,适用于鱼腥草等5种注射液中非法添加地塞米松磷钠的检查。 相似文献
20.
家兔亚硒酸中毒的病理形态学研究 总被引:1,自引:0,他引:1
给家兔分别肌肉注射不同剂量的亚硒酸钠,历时入周,复制出亚急性硒中毒的动物模型。病理形态学变化为:家兔的生长受到明显抑制,肝,肾,心,脾等组织器官损害严重如肝实质细胞变性,坏死;肾实质退行病变;心肌纤维变性,充血,肺淤血,水肿:脾萎缩,淋巴细胞坏死,肝,肾,心细胞内线粒高度肿胀,嵴减少,断裂或消失成空泡。 相似文献