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41.
在调查分析了解棉铃虫卵在田间呈核心理论分布型的基础上,研究了卵量调查方法的改进,应用序贯抽样检定防治标准,及统计资料的代换方法。根据棉铃虫卵在田间呈核心分布型,为了提高田间调查准确度,改进我国已经应用的田间取样方式,提出田间卵量调查方法是:以200株为取样量,采用平行线式,40个样点,每点单行五株。因为这样增多了样点和卵分布核心相遇的机会,经与原采用的单对角线式,双对角线式,棋盘式,分行式取样比较,平行线式取样准确度最高,降低了样本平均数代表性误差。为了节省田间卵量检查时间,可采用调查着卵株率计算百株卵量的办法,或对不同卵量密度的田块区别对待,百株卵量10粒以上检查100株,10粒以下检查200株。以田间百株卵量15粒或着卵株率11.77%为达到防治标准;卵量10粒或着卵株率8.36%为未达到防治标准,制定了序贯抽样检定防治标准的方法。检查卵量序贯抽样确定防治标准的方程:d_o=0.1127n-8.5353d_1=0.1127n 8.5353检查着卵株序贯抽样确定防治标准的方程:d_o=0.0998n-6.4228d_1=0.0998n 6.4228为了使用方便,制定了每次检查五株为单位的序贯抽样确定防治标准的田间实用检定表。实例计算表明,对棉铃虫卵和田间调查资料,进行变量分析,用对数和平方根代换均可。根据卵呈核心或嵌纹分布的特点,对数代换更为合理些。 相似文献
42.
J. Simon 《British poultry science》1980,21(4):309-313
1. A possible relationship between glucose tolerance and body‐fat content was examined in broilers selected at 2 and 4 weeks of age for fast or slow glucose disposal.
2. At 8 weeks of age, selected chickens were different in glucose tolerance but similar in body weight, food conversion efficiency, carcass composition and glucose‐induced insulin release.
3. Therefore, variations in glucose regulation and insulin sensitivity which are detectable at an early age, do not appear to be related to body composition in 8‐week‐old broilers. 相似文献
43.
Young pigs were exposed to an aerosol of a nonpathogenic strain of Escherichia coli and then were retained in air-pollutant exposure chambers for a 2-hour clearance period. In series 1 (n = 80 pigs), 40 exposed young pigs (principals; 15.5 days of age) were placed in an atmosphere of filtered room air + 50 ppm of atmospheric NH3 during the clearance period; control pigs were exposed to filtered room air without added NH3. In series 2 (n = 24 pigs), 12 exposed young pigs (principals; 6.2 days of age) were similarly maintained, but at a lower concentration of atmospheric NH3 (75 ppm). At the end of the clearance period pigs were killed and pulmonary bacterial clearance was determined. Pigs kept in the NH3-contaminated atmospheres (either concentration) harbored more bacteria, on the average, in their lungs than did the controls. If series 1 and 2 data were combined, pigs kept in the NH3-contaminated atmospheres had 51% more bacteria in their lungs than did the controls. Pulmonic weight and ratio of pulmonic weight to body weight of pigs kept in the NH3-contaminated atmosphere were greater than those of the controls in series 1, but not in series 2. Gross and histopathologic examinations of lung tissue generally revealed no differences between controls and principals in either series 1 or 2. 相似文献
44.
Male experimental rats (100 gm liveweight) were distributed into 10 groups of 8 animals each and received balanced diets, with the exception of lysine which was added to the diets in graded amounts in such a way that the lysine content of the diets ranged from 2.44 to 5.92 gm/16 gm N. After a feeding period of 7 days the animals received 3H- and 14C lysine injected intraperitoneally, 4 animals of each group were investigated for the total CO2 excretion and 14CO2 excretion during the first 2 hrs after the injection and for the urinary excretion of radioactivity (48 hours). The remaining animals in each group were used for determining the plasma amino acids and for establishing the specific radioactivity of free lysine in the liver and muscles after an 1-hour incorporation period. Total CO2 excretion was not found to be influenced by the lysine contents while the level of excretion of 14C activity through CO2 and that of specific 14C activity of CO2 increased with increasing lysine concentrations. This produced a broken curve pattern, showing an increased release of 14CO2 (under maintenance conditions) if the diet contained 4 gm lysine/16 gm N and more. Investigations for the specific 14C activity of free lysine in the liver, the main site of lysine oxidation, showed that the increase in 14CO2 release was due to an enhanced rate of lysine catabolism and was not brought about by changes in the pool volume or in specific radioactivity. The levels of urinary 14C excretion were not found to be related to the lysine content of the diets, whereas the curve pattern of 3H excretion observed 5 to 8 hrs after injection was similar to that of 14CO2 excretion. The lysine content of blood plasma and the content of free lysine in the liver increased continuously with increasing levels of dietary lysine. The methodological studies made in the present paper showed that in scientific research a determination of amino acid requirements on the basis of CO2 oxidation data may be a very exact and sensitive method. It will also yield values for maintenance requirements. 相似文献
45.
新鲜蔬菜硝酸盐含量测定的改进试粉法 总被引:11,自引:0,他引:11
为适应新鲜蔬菜硝酸盐快速检测的需要, 在现有试粉法的基础上对硝酸盐测定的试粉法进行了改良研究。结果表明, 本研究建立的直接以去离子水浸提蔬菜匀浆, 混合试粉配方为柠檬酸∶一水硫酸锰∶无水对氨基苯磺酸∶N - 1 - 萘乙二胺盐酸盐∶细锌粉= 30∶4∶1.6∶0.8∶1, 其加入量为0.1 g的改进试粉法, 对于溶液中硝酸盐含量在0~20 mg/L范围时, 显色吸光值与硝酸盐含量呈现良好的线性关系, 相关系数达0.9999, 方法回收率在97.7%~104.5%之间, 相对标准偏差2.71%。用本改进试粉法测定11种蔬菜的硝酸盐含量与国标法测定结果的t检验具有一致性。 相似文献
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AIM: To study whether Sca-1+ cells from fetal liver can be induced to differentiate into neuronal cells in vitro. METHODS:Sca-1+cells from 14 5-days-old murine fetal liver were isolated with a magnetic cell sorting kit, and were cultured in Dulbecco s modif ied Eagle s medium(DMEM)/F12 supplemented with 10%fetal bovine serum(FBS), and passaged at a rat io of 1 3 when cells reached more than 80%confluence.The 5 passage cells were induced by 10-3mol/Lβ-mercaptoethanol(β-ME)and 5×10-7 mol/L all-trans-retinoic acid(RA)for 24 hours, and then incubated in serum-free medium for 5 hours to 5 days.The characteristics of treated cel s were assayed by immunocytochemistry staining analysis at 5 hours, or 5 days.RESULTS: Cells treated with β-ME and RA exhibited neuronal phenotype and expressed neuron-specific protein such as neuron-specific nuclear protein (NeuN), neuronfilament-M, and neuron-specific tubulin-1 (TuJ-1) but not tau, MAP-2, or the astrocyte-specific marker glial fibrillary acidic protein (GFAP).CONCLUSION: Sca-1+ cells from fetal liver, of which most are regarded as hematopoietic stem cells, could differentiate into early immature neuronal cells in vitro. These findings suggest that Sca-1+ cells from fetal liver may be an alternative source in cell therapy and gene therapy of neural dysfunction. 相似文献