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71.
The investigation showed that stem-pitting Citrus tristeza virus (CTV)occurred commonly in citrus production areas in several varieties of Hunan Province. Accurate detection of CTV strains was performed by p23/PCR method, PCR and the results indicated that the most samples were infected with several CTV isolates. Three mild strains were isolated and their pathogenicity was identified by biological identification, it indicated that p23/PCR groups had uniformity with the pathogenicity of CTV isolates. Furthermore, three mild isolates were tested in the cross protection by analysis of biological symptoms and composition of p23 gene. Different protecting effects were observed among these strains and W17 mild isolate was effective. 相似文献
72.
73.
王成海 《信阳农业高等专科学校学报》2006,16(1):11-13
职业兴趣的汇聚与转移是默顿博士论文的第一部分。从科学发展的外部因素来理解科学是默顿论文的意义所在,他对职业兴趣的汇聚与转移的分析恰好为其找到了研究的突破口。用社会学方法来研究科学的发展,虽有其成功的一面,也有其局限性。 相似文献
74.
本文通过室内贴牌水培法及整株法,快速鉴定并验证了2013年采自湖南省不同地区稻田的50个稗草生物型对二氯喹啉酸的抗药性,试验结果表明:贴牌水培法所用的二氯喹啉酸甄别剂量为80mg/L;稗草死亡率越低,其抗性倍数(resistance factor,RF)越高,其中死亡率为0时,整株法测定的RF值高达896.07~1 209.38;贴牌水培法测定的稗草样本对二氯喹啉酸的ED50远低于整株法,但两种方法得到的不同稗草生物型对二氯喹啉酸的抗性水平趋势高度吻合。笔者认为以贴牌水培法测定的死亡率小于40%的稗草样本对二氯喹啉酸的抗性风险较高,值得深入研究。 相似文献
75.
Intermediate derivatisation method in the discovery of new acaricide candidates: synthesis of N‐substituted piperazine derivatives and their activity against phytophagous mites 下载免费PDF全文
Yong Xie Ying Xu Changling Liu Aiying Guan Lanfeng Ban Fei Ding Wei Peng 《Pest management science》2017,73(5):945-952
76.
针对原子物理学教学中电子壳层结构排布这一难点,介绍了一种简单、直观的三角形方法。该方法容易掌握,熟练掌握后对于教材中"原子的壳层结构"章节的学习有重要的作用。 相似文献
77.
Overestimation of canine albumin concentration with the bromcresol green method in heparinized plasma samples 总被引:5,自引:0,他引:5
Stokol T Tarrant JM Scarlett JM 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2001,30(4):170-176
Albumin concentrations are routinely measured in dogs with bromcresol green (BCG)-binding assays on automated chemistry analyzers. Several variables affect this assay, including the length of reaction time, sample type, and lack of specificity of BCG for albumin. We observed that albumin concentrations measured with BCG appeared higher in heparinized plasma samples in sick dogs. The objective of this study was to determine the effect of anticoagulant and assay procedure on BCG albumin concentrations in clinically ill dogs. We hypothesized that albumin concentrations would be overestimated in heparinized plasma compared with serum because of the combination of heparin and fibrinogen. Furthermore, we hypothesized that the overestimation would be influenced by assay parameters. Blood was collected from 32 clinically ill dogs into tubes containing heparin, citrate, or no anticoagulant. Citrate was chosen to assess the effect of fibrinogen in the absence of heparin. Albumin concentration was measured in all 3 sample types from each dog using 2 different BCG procedures on an automated chemistry analyzer. The BCG procedures (standard and modified) differed in the wavelengths used for absorbance readings (standard, 600/700; modified, 570/505) and the time point at which absorbance was measured (standard, 100 seconds; modified, 40 seconds). In addition, the modified method incorporated a sample blank. Globulin fractions, fibrinogen concentration, and indices of lipemia, hemolysis, and icterus were evaluated for their contribution to the overestimation of albumin concentration in heparinized plasma compared with serum samples. Albumin concentrations were significantly higher (P =.05) in heparinized plasma (mean +/- SE, 3.8 +/- 0.1 g/dL) than in serum (3.6 +/- 0.2 g/dL) or citrated plasma (3.2 +/- 0.1 g/dL). Overestimation was evident only with the standard BCG procedure. Multiple linear regression analysis indicated that fibrinogen was largely responsible for the higher albumin concentration in heparinized plasma with the standard method. Based on these results, heparin is not recommended as an anticoagulant for albumin measurement in dogs when using a BCG method unless the assay uses a sample blank and a reaction time of <1 minute. 相似文献
78.
为了找出支配鸡胆囊交感节后神经元的分布规律,选用体重1.5 kg~2.5 kg的成年母鸡6只,将CT-HRP溶液注入胆囊壁,动物存活3 d~4 d后,经左心室灌流固定,取内脏神经节、肾上腺神经节以及双侧胸、腰和荐段交感干神经节,制成50 μm的连续冰冻切片,TMB法呈色反应,置明视野显微镜下观片统计.结果发现,支配鸡胆囊的交感传出神经元胞体位于内脏神经节(占41.1%)、肾上腺神经节(占40.5%)和T2~T7交感干神经节(占18.4%),在交感干神经节中标记细胞的峰值位于T5、T6交感干神经节.所有的标记细胞以位于右侧的占优势. 相似文献
79.
80.
Screening crop accessions for allelopathic activity is of paramount importance for crop allelopathy research. Previous bioassays often did not use a mixed culture of donor and target plants, did not use soil and were not conducted under natural conditions. In this study, we designed an inhibitory‐circle method in which a rice accession (donor plant) and Echinochloa crus‐galli (target plant) were cultured together in paddy soil under natural conditions. First, we determined that the highest allelopathic activity of allelopathic rice accession PI312777 was at the 5‐leaf stage, and the suitable distance of rice seedlings and E. crus‐galli was 12 cm apart. This method was then validated by a field test. A further 40 rice accessions were evaluated for allelopathic activity to E. crus‐galli using this method. Two rice accessions, PI312777 and Taichung Native 1, had highly allelopathic activity to E. crus‐galli (inhibitory rate > 50%), while another accession, Lemont, had non‐allelopathic activity. These experimental results were in accordance with previous studies using direct field experiments. The inhibitory‐circle method integrated three necessary conditions, that is donor and target plants grown together, with soil as the medium and under natural conditions for reliable results. The ‘inhibitory‐circle method’, which combined donor and target plants, soil medium and field conditions, can give reliable results in one step, compared with laboratory screening methods. Also, the ‘inhibitory‐circle method’ gave results in 30‐35 days, thereby substantially reducing the requirements for time, labour and cost. 相似文献