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911.
施氮对油菜硫、硼、钼和硒营养的影响 总被引:1,自引:0,他引:1
研究了不同氮水平与杂交油菜收获期植株各器官硫、硼、钼和硒等元素含量和积累的关系。植株各器官(种子除外)的硫以及种子和主茎中的硼含量随施氮量的增加呈先升后降的趋势,但植株各器官的钼、硒和种子的硫以及其余各器官的硼含量随施氮量的增加有所下降。种子和主茎的硫以及果壳的钼、硼和硒的含量及积累量较高。 相似文献
912.
青枯菌潜伏浸染对花生的影响 总被引:2,自引:0,他引:2
用青枯菌对20个花生品种进行人工接种,研究了青枯菌潜伏侵染对花生根系、根瘤数、生物产量及结实性状的影响。结果表明,青枯菌潜伏侵染对花生生长发育有普遍的抑制作用,不同花生品种对潜伏浸染的反应存在广泛差异。 相似文献
913.
2005年12月7日,经湖南省科学技术奖励评审委员会评审、省科学技术奖励委员会审定、省人民政府批准,中国工程院院士卢锡城和国家杂交水稻工程技术研究中心研究员罗孝和被授予2005年度湖南省科学技术杰出贡献奖。 相似文献
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915.
大连紫海胆人工育苗的初步研究 总被引:9,自引:1,他引:9
本文报道了有关海胆人工育苗的方法,并对大连紫海胆幼虫的生长发育和变态作了详细描述。大连紫海胆的幼虫可分为,棱柱幼虫、二腕长腕幼虫、四腕长腕幼虫、六腕长腕幼虫和八腕长腕幼虫五个时期。在山东省荣城浬岛海区,大连紫海胆的育苗时间为7—8月。在水温为23—24℃时,自受精卵发育至变态成幼海胆的时间大约需要19—20天。幼虫的饵料以角毛藻为最佳,而幼海胆的饵料早期为底栖硅藻,后期以石药较为合适。 相似文献
916.
Haemocytes of the giant freshwater prawn, Macrobrachium rosenbergii, were investigated for the induction of apoptosis after phagocytosis of pathogenic yeasts, bacteria and non-pathogenic latex beads in vitro. Isolated haemocytes of M. rosenbergii were cultured at a ratio of 1:50 haemocytes to pathogen with the yeast Debaryomyces hansenii, the bacteria Aeromonas hydrophila or Enterococcus faecium, or with latex beads at 25 degrees C for 2 h, followed by washing to remove free particles. At least 200 haemocytes were counted to determine the phagocytosis rate, and the results showed that haemocytes engulfed latex beads at a higher rate than the aquatic pathogens. By transmission electron microscopy, the yeast- or bacterium-engulfing haemocytes displayed morphological changes characteristic of apoptosis, including formation of cytoplasmic vacuoles, chromatin condensation and fragmentation of nuclei. This pathogen-induced apoptosis was further confirmed by DNA laddering and TUNEL (terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick-end-labelling) assays. Neither haemocytes treated with latex beads nor uninfected haemocytes (control group) showed signs of apoptosis after 48 h in culture. 相似文献
917.
Polyphosphorylated L-ascorbic Acid: A Stable Form of Vitamin C for Aquaculture Feeds 总被引:1,自引:0,他引:1
Blake F. Grant Paul A. Seib Ming-Long Liao Kenneth E. Corpron 《Journal of the World Aquaculture Society》1989,20(3):143-157
A protected form of vitamin C, L-ascorbyl-2-poly phosphate (APP), was tested for safety and efficacy in fishes. Phosphorylation of the 2-hydroxyl group protected the 2,3-enediol of L-ascorbic acid against oxidation. When APP was added to feed, about 15% of its vitamin C activity was lost during milling and storing 5–7 d at ambient temperature. Stability of APP in pelleted feeds at 25 or 40 C was up to 83 times or 45 times greater than that of ascorbic acid (AA), respectively. In later tests, trout feed mash, steam-pelleted in triplicate, frozen, and shipped on dry ice before analysis, had 46% loss of AA and no apparent loss of APP. With 16% milling loss (highest detected in trout feeds assayed in initial tests) and 22% storage loss after 90 d, conservative APP mix rates were estimated. Mixing 153 g L-ascorbate-equivalent as APP per metric ton of airdry ingredients (153 ppm) would give 128 ppm in the finished feed after steam-pelleting and 100 ppm after 60–90 d storage at 40 C. Low-temperature extrusion of Oregon-Moist salmon feed reduced AA slightly. Ascorbic acid oxidized in frozen storage and while thawing and, after 12 h at room temperature, only trace amounts remained. Ascorbyl-2-polyphosphate at 0.05 to 0.2 times that of equimolar AA in casein-base or practical feeds supported long-term growth and development in rainbow trout and other fishes. Trout feeding trials with practical feeds in actual production regimens documented APP activity at growth rates approaching the maximum for trout farming. Corrected for greater stability, APP antiscorbutic activity appeared to be comparable to that of AA on a molar-equivalent basis. Similarly, apparent equimolar activity was inferred from estimated equilibrium levels of liver, kidney, and whole-body AA and L-ascorbyl-2-sulfate (AS) after prolonged APP use in trout feeds. Fathead minnow growth and reproduction in egg-to-egg life-cycle tests also confirmed APP safety and efficacy as a stabilized source of vitamin C for feeds. None of the typical lesions of scoliosis, malformed gill lamellae, and crenulated opercles, nor conditions of poor health, anorexia, and eventual torpor seen in vitamin C-deficient controls occurred in trout fed APP. No liver pathology was evident in trout fed APP for 252 d at 1.7 to 3.3 times the National Research Council's recommended vitamin C (equivalent) rates. 相似文献
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