全文获取类型
收费全文 | 312篇 |
免费 | 12篇 |
国内免费 | 2篇 |
专业分类
林业 | 71篇 |
农学 | 24篇 |
基础科学 | 1篇 |
87篇 | |
综合类 | 24篇 |
农作物 | 12篇 |
水产渔业 | 5篇 |
畜牧兽医 | 85篇 |
园艺 | 7篇 |
植物保护 | 10篇 |
出版年
2023年 | 2篇 |
2021年 | 8篇 |
2020年 | 4篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 2篇 |
2014年 | 11篇 |
2013年 | 25篇 |
2012年 | 12篇 |
2011年 | 11篇 |
2010年 | 9篇 |
2009年 | 9篇 |
2008年 | 23篇 |
2007年 | 13篇 |
2006年 | 18篇 |
2005年 | 14篇 |
2004年 | 13篇 |
2003年 | 13篇 |
2002年 | 11篇 |
2001年 | 2篇 |
2000年 | 8篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 10篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1985年 | 3篇 |
1973年 | 2篇 |
1969年 | 2篇 |
1949年 | 2篇 |
1936年 | 2篇 |
1935年 | 1篇 |
1934年 | 2篇 |
1932年 | 2篇 |
1931年 | 4篇 |
1930年 | 1篇 |
1929年 | 2篇 |
1928年 | 3篇 |
1925年 | 2篇 |
1918年 | 4篇 |
1917年 | 3篇 |
1916年 | 2篇 |
1908年 | 2篇 |
排序方式: 共有326条查询结果,搜索用时 31 毫秒
91.
Hermann Buerstmayr Michael Stierschneider Barbara Steiner Marc Lemmens Michaela Griesser Eviatar Nevo Tzion Fahima 《Euphytica》2003,130(1):17-23
Head blight of wheat (FHB, scab) caused by Fusarium spp. has been associated with yield and quality losses in many wheat-growing regions. In tetraploid wheat sources of resistance
are scarce. In the search for novel sources of resistance, 151 Triticum dicoccoides genotypes, originating from 16 habitats in Israel and one habitat in Turkey together with several control genotypes, were
evaluated for reaction to fungal spread (Type II resistance) in replicated greenhouse experiments. Significant genetic diversity
was found among the tested genotypes, the broad sense heritability for Type II FHB resistance was 0.71. Most of the tetraploid
accessions were highly susceptible, only a few showed moderate resistance. Among the eight T. dicoccoides lines with the lowest relative infection rates, five originated from the Mt. Gerizim population, and three from the Mt. Hermon
population. None of the
T. dicoccoides lines reached the level of resistance present in the common wheat cultivar Sumai3.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
92.
Stefan Fleck Inga Mölder Mascha Jacob Tobias Gebauer Hermann F. Jungkunst Christoph Leuschner 《Annals of Forest Science》2011,68(7):1173-1185
Introduction
Sight-based field measurements of tree crown projection area and canopy height are common praxis in forest science but difficult to validate. We quantified their measurement errors based on the virtual representation of an 11-species old-growth forest provided by high-resolution terrestrial LIDAR (light detection and ranging) measurements. 相似文献93.
Michelitsch A Rückert U Rittmannsberger A Seger C Strasser H Likussar W 《Journal of agricultural and food chemistry》2004,52(6):1423-1426
A simple and accurate differential pulse polarographic method has been developed for the determination of oosporein in the culture broth of the fungus Beauveria brongniartii. This hydroxybenzoquinone derivative is the only major secondary metabolite secreted by this entomopathogenic fungus, which is used as biological pest control agent (BCA) against Melolontha melolontha larvae. It can be found in the host organism as well as in the formulated product. The polarographic behavior of oosporein was examined in various buffer systems over the pH range 3-10. In Britton-Robinson buffer/methanol solution (3:7 v/v, pH 5.5) the differential pulse polarograms exhibited reproducible peaks at E(p) = -0.18 V vs silver/silver chloride/potassium chloride (3 M). Under these conditions, a plot of peak height vs concentration of oosporein was found to be linear over the range 5.9 x 10(-)(7) to 2.5 x 10(-)(5) M (0.18-7.74 microg mL(-)(1); r = 0.9998). The detection limit was calculated to be 54 ng mL(-)(1). To evaluate the concentration of oosporein, the standard addition method was applied. The analysis of oosporein in the culture broth led to a mean value of 524.9 microg mL(-)(1) broth with a relative standard deviation (S(rel)) of +/-2.6%. The proposed polarographic method is accurate, not time-consuming, and it is of low cost because no separation steps are necessary. 相似文献
94.
Hermann Bauwe 《Genetic Resources and Crop Evolution》1990,38(1):39-48
Zusammenfassung Nach einem kurzen historischen Überblick über wesentliche Entdeckungen auf dem Gebiet der Photosyntheseforschung werden Fragen der Regulation der Photosynthese höherer Pflanzen behandelt. Dabei wurden vor allem die an der Ribulose-1,5-biphosphat Carboxylase/Oxygenase angreifenden Regulationsprinzipien berücksichtigt.
相似文献
Molecular regulation of photosynthetic processes
Summary Following a short survey on the history of photosynthesis research some of the main principles of photosynthetic regulation are discussed. Especially, those mechanisms are considered which are involved in the regulation of ribulose-1,5-bisphosphate carboxylase/oxygenase.
, . ¶rt; -1,5- / .
相似文献
95.
Zusammenfassung Ein mathematisches Verfahren wird beschrieben, mit dessen Hilfe auf mögliche, durch Translokationen bedingte Paarungspräferenzen der Chromosomen in der Meiose bei Autotetraploiden geschlossen werden kann. Bei Gerste konnte mit Hilfe von einfachen und multiplen Translokationen im duplex-heterozygoten Zustand gezeigt werden, daß die Strukturumbauten offenbar in gewissen Grenzen zu präferenzieller Paarung der an den Translokationen beteiligten Chromosomen führten.
Herrn Prof. Dr. Drs. h. c.Hans Stubbe zum 75. Geburtstag gewidmet. 相似文献
Preferential Pairing of the Chromosomes of Autotetraploid Barley — a Mathematical Model
Summary A mathematical method is described which can be used for ascertaining possible effects of translocations on chromosome pairing during meiosis in autotetraploids. Using single and multiple translocations in duplex-heterozygous condition in barley, it has been shown that the structural rearrangements apparently resulted in a certain amount of preferential pairing of the chromosomes involved in the interchanges.
.
, , . - , , , .
Herrn Prof. Dr. Drs. h. c.Hans Stubbe zum 75. Geburtstag gewidmet. 相似文献
96.
Shoots of spruce (Picea abies (L.) Karst.) seedlings grown in solution culture were fumigated with sulfur dioxide or ozone, or with a combination of both for 60 days. Dry weights of the shoots exposed to O3 and SO2/O3 were increased over the controls. Uptake rates of calcium, magnesium, potassium and nitrate from the nutrient solutions were altered in dependence on fumigation, time of exposure and stage of plant development. Uptake rates of all ions by the seedlings fumigated with SO2 first increased, but later on decreased as compared to the control. Fumigation with O3, or O3 in combination with SO2 affected uptake of the various nutrients differently. The effects of the pollutants on the concentrations of calcium and magnesium in the various parts of the seedlings indicate that the changes are not only due to altered water and ion uptake but may be related to various effects in ion transport and plant metabolism. 相似文献
97.
Zöllner P Jodlbauer J Kleinova M Kahlbacher H Kuhn T Hochsteiner W Lindner W 《Journal of agricultural and food chemistry》2002,50(9):2494-2501
The content of zearalenone and its metabolites in urine and tissue samples from pigs fed zearalenone-contaminated oats was established by analytical methods combining solid-phase extraction cleanup of the samples with highly selective liquid chromatography-mass spectrometry (LC-MS)/MS detection. Investigation of the urine samples revealed that approximately 60% of zearalenone was transformed in vivo to alpha-zearalenol and its epimer beta-zearalenol in a mean ratio of 3:1. Zeranol and taleranol as further metabolites could only be detected in trace amounts. Zearalanone was identified at considerable concentrations, though only in a couple of samples. In contrast, liver samples contained predominantly alpha-zearalenol, and to a minor extent beta-zearalenol and zearalenone, with a mean ratio of alpha-/beta-zearalenol of 2.5:1, while zeranol, taleranol, or zearalanone could not be identified in any of the investigated samples. The degree of glucoronidation was established for zearalenone as 27% in urine and 62% in liver; for alpha-zearalenol as 88% in urine and 77% in liver; and for beta-zearalenol as 94% in urine and 29% in liver. Analyses of muscle tissue revealed relatively high amounts of nonglucuronidated zeranol and alpha-zearalenol together with traces of taleranol and zearalenone, indicating that the metabolism of zearalenone and its metabolites is not restricted to hepatic and gastrointestinal metabolic pathways. 相似文献
98.
Siewert C Böttcher A Hellige M Beyerbach M von Rautenfeld DB Seifert H 《Berliner und Münchener tier?rztliche Wochenschrift》2011,124(5-6):257-264
This study tested for the first time an optoelectronic device (Perometer*) measuring limb volume of horses. An analysis of its application was performed regarding the influence of different types of physical exercise on the volume of the extremities. 40 horses were divided into four groups often horses, each group being exposed to exercise, differing in kind and duration of lunging, horse-ridden and riderless. The volume measurement was performed by determining the inactive value (I) after a twelfe-hour standing period, the load value (II) immediately after exercise and recovery value (III) one hour after exercise. The results showed a highly significant decrease in limb volume of 5.7% between values (I) and (II), as well as a highly significant increase of 68% between (II) and (III). The volume changes observed in male horses were significantly higher than in female horses. Volume changes in horse-ridden groups were higher than riderless ones, but not significant. There were fewer leg volume changes at low ambient temperatures (1-12 degrees C) compared to high temperatures (23-31 degrees C), but these were not statistically significant. Well-trained horses showed lower volume changes than less trained horses (not statistically significant). The Perometer is a fast and reliable tool for measuring limb volume of horses. The ICC (Interclass Correlation Coefficient) calculated a high measurement reproducibility of 0.996. A variance analysis showed no significant differences between the three repeated leg measurements. Thus, the Perometer can be used for monitoring and quantifying edema and documenting limb volume changes resulting from training, wearing compression stockings or bandages, manual lymph drainage. 相似文献
99.
Hermann Richter 《Forstwissenschaftliches Centralblatt》1918,40(10):370-372
Ohne Zusammenfassung 相似文献
100.
快速检测小反刍兽疫病毒RT—LAMP方法的建立 总被引:2,自引:1,他引:2
本研究采用一步法反转录环介导等温扩增技术(RT-LAMP)建立了一种快速、灵敏、高度特异的检测小反刍兽疫病毒(PPRV)的方法.针对PPRV-N基因保守区域设计4条引物,在Bst大片段聚合酶的作用下,可以实现DNA的梯状等温扩增.优化RT-LAMP的反应体系,并检验其灵敏性、特异性.一步法RT-LAMP检测方法从核酸抽提到检测结果出现仅需70 min,该方法具有良好的特异性,与同属的犬瘟热病毒无交叉反应,灵敏度是RT-PCR的1 000倍,是巢式RT-PCR的100倍.结果证明,RT-LAMP方法可快速、灵敏、特异、经济地检测PPRV,在基层和实验室都具有良好的应用前景. 相似文献