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471.
Abstract The new planthopper taxon, Garumnella bella gen.n. , sp.n. , from Xizang, China, is described and illustrated, including external morphology of adult and eggs and structures of the male and female genitalia. The new genus is compared with Garumna Melichar and Paragarumna Muir, resulting in Paragarumna ( syn.n. ) being placed as a junior synonym of Garumna, with two new combinations, i.e. Garumna pseudolepida (Muir) comb.n. and Garumna melichari Baker comb.rev. New locality records for Garumna species are given. The morphology of the genitalia and egg of a copulating pair of the new genus is investigated. The female has a ventrally sclerotized posterior vagina forming a torsion groove, an unusual long membranous anterior vagina and an enlarged common oviduct. During copulation both the aedeagus and the torsion groove appear tightly interlocked, which may help to maintain the copulatory position. The aedeagus is observed in the bursa copulatrix. 相似文献
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WENDA CHENG SHUANG XING YI CHEN RONG LIN TIMOTHY C. BONEBRAKE AKIHIRO NAKAMURA 《Ecological Entomology》2018,43(3):304-309
1. Morphological characteristics, especially coloration, are related to thermoregulation and camouflage, both of which are crucial for species survival and fitness. In cool environments such as the understorey of closed rainforests, darker organisms have thermal advantages and may be able to absorb heat more efficiently. However, such habitats are also suitable for darker organisms with respect to camouflage, making it difficult to elucidate whether the association of dark‐coloured organisms with shady environments is a consequence of thermal stress or predation pressure, or both. 2. In this study, butterfly communities were surveyed and artificial butterflies (mealworms attached to plastic sheeting to mimic adult butterflies) used to test whether differences in wing luminance are related to predation rates within open and closed habitats in monsoonal tropical forests of southwestern China. 3. Using artificial butterflies, significantly lower predation rates were found for dark‐coloured artificial butterflies within closed habitats, whereas such relationships were not found within open habitats. It was found that actual butterfly communities were also significantly darker in closed than in open habitats. 4. These results demonstrate that darker colours may have the effect of reducing predation rates in shady environments and that different habitat types can have contrasting effects on luminance and therefore predation risk. 相似文献
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基于航空遥感影像,利用地理信息系统(ArcGIS 10.2)和景观格局分析(Fragstats 4.2)软件,通过主成分分析(PCA)和多元线性回归分析对研究区城市化水平进行量化,选取覆盖研究区典型的“城—郊—乡”样带,进行表层土壤取样,测定总有机碳(C)、全氮(N)、全磷(P)的含量并分析其空间变化特征。结果表明:快速的城市化进程导致了土壤C、N、P化学计量特征的空间分异,“城—郊—乡”梯度上变异系数都较大,尤其城区各元素的变异系数分别为84.08%、76.95%和81.34%,属于强变异,表明土壤表层C、N、P含量空间分布极不均衡。研究区土壤C、N、P含量均表现为城区显著高于郊区的特征,与郊区土壤相比,城区土壤C含量较高,说明人为活动造成城区土壤明显的有机质富集现象。城区土壤P含量高于郊区和乡村,城市化过程加剧了城区土壤P的富集,也使该地区水体(主要是滇池)面临富营养化风险。分析城市化过程中强烈的人类活动干扰对土壤C、N、P含量及其化学计量特征,对于提高城市土壤管理水平、改善生态环境、促进城市生态系统健康持续发展具有重要意义。今后昆明市在进行城市绿化时可有针对性地选择部分豆科固氮植物加强生物固氮,目的是提高土壤N含量的同时促进城区土壤丰富的P被吸收利用,在一定程度上预防以及减轻P对水体的危害。 相似文献
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木贼麻黄(Ephedra equisetina)具有重要的药用和经济价值,在水土保持、生态平衡、荒漠化防治等方面也发挥重要作用,被列为国家二级保护植物。全球气候变化和人类活动严重威胁到木贼麻黄资源保护与利用,因而预测其潜在适生区空间变化具有重要意义。基于最大熵(MaxEnt)模型和ArcGIS软件,结合201条木贼麻黄在中国的有效分布记录和21个环境变量,预测在自然环境影响及人类活动干扰下中药材木贼麻黄适生区分布,并将木贼麻黄高适生区与土地利用类型进行叠加分析。结果表明:(1)模型添加人类活动因子后曲线下面积(AUC)值由0.919升至0.948,预测结果精度提高,而添加人类活动因子使木贼麻黄适生区面积严重减少,部分适生区等级退化,其分布愈破碎化稀疏零散;(2)木贼麻黄适生区多集中分布于新疆、甘肃、宁夏、陕西和山西地区,未来时期两种情景下木贼麻黄适生区都出现不同程度的扩张,RCP2.6-2050年相对当前时期高适生区面积增加最多;(3)参与建模的环境因子中贡献度较高的酸碱度(pH)、海拔(Altitude)和年平均温度(Bio1)对木贼麻黄地理分布有关键影响;(4)未来时期下木贼麻黄高适生区的几何质心出现不同程度向东迁移的现象,多分布于甘肃省境内;(5)木贼麻黄高适生区部分土地已经被开发利用,剩余未利用的土地分布于新疆、甘肃、内蒙古和宁夏地区,可在这些地区因地制宜发展木贼麻黄种植业。为木贼麻黄的就地、迁地保护、优先保护区以及人工种植选地提供理论依据,这对木贼麻黄资源保护与利用具有重要的现实意义。 相似文献
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BOUCOT A.J RONG JIA-YU CHEN XU SCOTESE C.R 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2003,36(2):119-131
Compilation of the marine, benthic megafossils from approximately the mid-Ashgill of the Mediterranean region, including much of Central and Southern Europe plus North Africa, and elsewhere indicates a warm interval featuring bioclastic limestone and a warm climate marine fauna. These mid-Ashgill faunas immediately precede the latest Ashgillian, Hirnantian, cool interval that featured widespread glaciation, and are underlain by typical, cold water, Mediterranean Realm, older Ordovician rocks and faunas. The cause or causes responsible for the brief warm interval are uncertain, but may have involved a warm water gateway that is geographically still not located. There is a possibility that South Africa was similarly affected by this roughly mid-Ashgillian marine situation. Early Paleozoic bauxite minerals and kaolins in northwestern Sudan and kaolins elsewhere in North Africa may represent the same time interval, which would suggest that there was a non-marine amelioration of the local climate as well as the marine effects. 相似文献