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101.
The salt-soluble proteins in barley grain selected for high-lysine content (Hiproly, CI 7115 and the mutants 29 and 86) and of a control (Carlsberg II) with normal lysine content, contain identical major proteins as determined by MW and electrophoretic mobility. The concentration of a protein group with a high lysine content varies significantly among the barleys examined. One protein, present in large amounts in Hiproly, is assumed to be partially responsible for the high-lysine character of Hiproly, CI 7115 and the mutants 29 and 86. 相似文献
102.
Soraya Guichard Christian Gary Cherubino Leonardi Nadia Bertin 《Journal of Plant Growth Regulation》2005,24(3):201-213
The influence of air vapor pressure deficit (VPD) and plant fruit load on the expansion and water relations of young tomato
fruits grown in a glasshouse were evaluated under summer Mediterranean conditions. The contributions of phloem, xylem and
transpiration fluxes to the fruit volume increase were estimated at an hourly scale from the growth curves of intact, heat-girdled
and detached fruits, measured using displacement transducers. High VPD conditions reduced the xylem influx and increased the
fruit transpiration, but hardly affected the phloem influx. Net water accumulation and growth rate were reduced, and a xylem
efflux even occurred during the warmest and driest hours of the day. Changes in xylem flux could be explained by variations
in the gradient of water potential between stem and fruit, due to changes in stem water potential. Misting reduced air VPD
and alleviated the reduction in fruit volume increase through an increase in xylem influx and a decrease in fruit transpiration.
Under low fruit load, the competition for assimilates being likely reduced, the phloem flux to fruits increased, similarly
to the xylem and transpiration fluxes, without any changes in the fruit water potential. However, different diurnal dynamics
among treatments assume variable contributions of turgor and osmotic pressure in F3 and F6 fruits, and hypothetical short-term
variations in the water potential gradient between stem and fruit, preventing xylem efflux in F3 fruits. 相似文献
103.
对T 4代转基因番木瓜进行了分子生物学和果实品质分析,结果表明,筛选获得的转基因番木瓜均为转番木瓜环斑病毒(PRV)复制酶突变体基因(RP),且对PRV抗性达到了高抗或免疫,RP基因在转基因植物中能稳定遗传至后代并在RNA水平上表达。在田间种植时,转基因木瓜的生长状况普遍好于普通番木瓜,尤其在生长后期(10月以后),普通番木瓜100%发病(大规模种植时),而大部分(约91.8%)转基因植株生长良好,果实较多且表面光洁、基本上无环斑。与非转基因亲本相比,T 4代转基因番木瓜的果实长度增加2.6%~5%,果实直径变小0.6%~1.5%,果肉厚度增加了12%~15%,因而果实形状与亲本相近或更好,且信用价值更高。转基因番木瓜果实中水分、蛋白质、氮、脂肪、还原性糖、维生素A、维生素C和类胡萝卜素的含量与对照都无显著性差异,即转基因番木瓜与亲本具有实质等同性,这表明转入的外源基因对番木瓜果实品质没有不良影响。 相似文献
104.
土壤活性有机质及其与土壤质量的关系 总被引:88,自引:2,他引:86
活性有机质是土壤的重要组成部分 ,主要包括溶解性有机碳、微生物生物量、轻组有机质。它在土壤中具有重要作用 :(1)可以表征土壤物质循环特征、评价土壤质量 ,可以作为土壤潜在生产力以及由土壤管理措施引起土壤有机质变化的早期指标 ;(2 )在养分周转中起重要作用 ,是植物的养分库 ,可以提供植物所需要的养分如氮、磷、硫等 ;(3)能稳定土壤结构 ,对维持团粒结构稳定性有重要作用。从土壤养分、土壤物理、化学性质方面讨论了活性有机质与土壤质量的关系。土壤中的溶解性有机碳、微生物生物量碳氮含量与土壤有机碳、全氮和碱解氮等物质的含量呈正相关。活性有机质受土壤质地、含水量、温度等因素影响 ,与土壤酸碱度、阳离子交换量等也有关。土壤微生物生物量碳和微生物量 C/有机碳比与土壤粘粒、粉粒含量呈正相关、与砂粒含量呈负相关 相似文献
105.
106.
Does mother really know best? Oviposition preference reduces reproductive performance in the generalist parasitoid Aphidius ervi 总被引:1,自引:1,他引:0
Lee M. Henry David R. Gillespie & Bernard D. Roitberg 《Entomologia Experimentalis et Applicata》2005,116(3):167-174
The reproductive success of female parasitoids is dependent on their ability to accurately assess the suitability of a host for larval development. For generalist parasitoids, which utilize a broad range of species and instars as hosts, a set of assessment criteria determines whether a host is accepted or rejected. The suitability of a host, however, can only be imperfectly assessed by the female parasitoid, which can result in the selection of lesser quality hosts for oviposition. In this study we explored the disparity between host quality and host preference using the generalist koinobiotic parasitoid Aphidius ervi Haliday (Hymenoptera: Aphidiidae) and the host Aulacorthum solani (Harris) (Homoptera: Aphididae), the foxglove aphid. The second instar hosts produced the highest level of reproductive success, while third and fourth instars resulted in a substantially reduced reproductive performance. When given a choice of host instars, parasitoids preferred the older hosts for oviposition disregarding their reduced suitability for larval development. Results are discussed in context of mechanisms involved in A. ervi host selection and biases in the criteria used to assess hosts that may arise when parasitoids transfer host species between generations. 相似文献
107.
Marc I. Förschler Antoni Borras Josep Cabrera Toni Cabrera Juan C. Senar 《Journal of Ornithology》2005,146(2):137-140
Habitat quality is generally thought to affect breeding success. We tested this effect comparing differences in clutch size and reproductive success between citril finch Serinus citrinella sub-populations closely located (<5 km) but differing in habitat quality, within the Port del Comte mountain, in the Catalonian Pre-Pyrenees. We found that birds in the low quality area (Bofia) showed significantly lower hatching, breeding and nesting success than finches in the high quality area (Vansa). These differences in reproductive success fit well with recently found differences in citril finch body mass, fat score, diet, survival rate and speed of moult between these two localities. 相似文献
108.
109.
110.
蔗糖磷酸合成酶(SPS)与果实品质及成熟衰老的研究进展 总被引:7,自引:1,他引:6
从蔗糖磷酸合成酶(sucrose phosphate synthase,SPS)基本性质、SPS与果实糖的积累、相关酶类和外源刺激、乙烯和呼吸、果实软化的火系及SPS基因的克隆与表达调控等几方面综述了国内外近年来对SPS的研究进展。 相似文献