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51.
中华真地鳖低龄若虫消化道结构及取食习性   总被引:4,自引:3,他引:4  
解剖喂食不同饲料中华真地鳖EupolyphagasinensisWalker的低龄若虫 ,结果表明 ,低龄若虫消化道与成虫消化道结构相同 ,具有胃盲囊和马氏管 ;嗉囊、中肠和后肠分别占消化道总长的比率与中龄若虫相同 ,具有消化食物的能力。观察消化道各部分的滞留物变化情况 ,发现 1龄若虫取食了饲养土中的腐殖质和配合饲料 ,表明孵化后的若虫需要喂食以满足营养需要。  相似文献   
52.
贺兰山不同生境旱生灌木的解剖学研究   总被引:8,自引:1,他引:8  
贺兰山荒漠地带三种不同基质生境的20种旱生灌木的营养器官的比较解剖学研究表明:其共同特点是叶片的表面积/体积的比值小,叶表具厚的角质层、表皮毛,气孔下陷、并具孔下室,叶向中栅栏组织发达;轴器官中木栓层细胞层数多,皮层较厚,机械组织发达,木薄壁组织及髓部细胞的细胞壁术化加厚,根内都具周皮、木质部的导管分子大小不一、频率较高。此外,根、茎、叶中普遍存在粘液细胞和草酸钙结晶,部分植物的根和茎内有异常维管组织。这些结构特征都与早生环境相关,而不同基质生境中生长的植物尚存在一定差异。  相似文献   
53.
A new genus and species in the eucalypt group of the Myrtaceae is described. Stockwellia quadrifida D.J. Carr, S.G.M. Carr & B.Hyland gen. et sp. nov. is a rainforest tree of restricted distribution on the Atherton Tableland, North Queensland, Australia. Molecular data suggest that it is the sister taxon to Eucalyptopsis and this is supported by morphological characters. The prolonged hypanthium and reduced perianth appear to be synapomorphies for these two genera and the circumscissile hypanthium a synapomorphy shared with Allosyncarpia . Stockwellia differs from Eucalyptopsis by the distinct, albeit reduced, perianth and the hypanthium splitting into four segments at anthesis. The relationship of these two genera indicates an historical biogeographical link between New Guinea and the Queensland wet tropics region.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 415–421.  相似文献   
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Species of fleshy yellow Cantharellus are known as chanterelles, which are among the most popular wild edible mycorrhizal mushrooms in the world. However, pure culture isolates of Cantharellus are rare. We report an efficient isolation technique of the Japanese golden chanterelle, Cantharellus anzutake, from its ectomycorrhizal root tips. Field-sampled fresh ectomycorrhizal root tips of C. anzutake on various hosts such as pines, spruce, and oaks were vortexed with 0.005% Tween 80 solution, surface sterilized with 1% calcium hypochlorite solution, rinsed with sterilized distilled water, and placed on modified Norkrans’ C (MNC) agar plate medium. Most ectomycorrhizal root tips of C. anzutake produced yellowish mycelial colonies within a few months. In contrast, tissue isolation from basidiomata provided limited cultures of C. anzutake but much contamination of bacteria and molds, even on media that contained antibiotics. The established C. anzutake cultures had clamp connections on the hyphae and contained intracellular oily droplets. These cultured isolates were identified as C. anzutake by sequence analysis of the rRNA internal transcribed spacer (ITS) region and translation elongation factor EF1-alpha (tef-1) genes.  相似文献   
57.
This study quantitatively documents the progressive development of sexual dimorphism of the vocal organs along the ontogeny of the goitred gazelle (Gazella subgutturosa). The major, male‐specific secondary sexual features, of vocal anatomy in goitred gazelle are an enlarged larynx and a marked laryngeal descent. These features appear to have evolved by sexual selection and may serve as a model for similar events in male humans. Sexual dimorphism of larynx size and larynx position in adult goitred gazelles is more pronounced than in humans, whereas the vocal anatomy of neonate goitred gazelles does not differ between sexes. This study examines the vocal anatomy of 19 (11 male, 8 female) goitred gazelle specimens across three age‐classes, that is, neonates, subadults and mature adults. The postnatal ontogenetic development of the vocal organs up to their respective end states takes considerably longer in males than in females. Both sexes share the same features of vocal morphology but differences emerge in the course of ontogeny, ultimately resulting in the pronounced sexual dimorphism of the vocal apparatus in adults. The main differences comprise larynx size, vocal fold length, vocal tract length, and mobility of the larynx. The resilience of the thyrohyoid ligament and the pharynx, including the soft palate, and the length changes during contraction and relaxation of the extrinsic laryngeal muscles play a decisive role in the mobility of the larynx in both sexes but to substantially different degrees in adult females and males. Goitred gazelles are born with an undescended larynx and, therefore, larynx descent has to develop in the course of ontogeny. This might result from a trade‐off between natural selection and sexual selection requiring a temporal separation of different laryngeal functions at birth and shortly after from those later in life. J. Morphol. 277:826–844, 2016. © 2016 Wiley Periodicals, Inc.  相似文献   
58.
A collection of subfossil wood of Pinus sylvestris (Scots pine) was exposed to X-ray densitometry. The collection of 64 samples from the southern boreal forest zone was dendrochronologically cross-dated to a.d. 673-1788. Growth characteristics were determined by performing density profiles including the following parameters: minimum density, earlywood and latewood boundary density, maximum density, earlywood width, earlywood density, latewood width, latewood density, annual ring width and annual ring density. Seven out of the nine parameters were found to contain non-climatic growth trends and six were found to be heteroscedastic in their variance. Tree-specific records were indexed, to remove the non-climatic growth trends and stabilize the variance, and combined into nine parameter-specific tree-ring chronologies. Growth characteristics of the pines changed in parallel with the generally agreed climatic cooling from the Medieval Warm Period to the Little Ice Age: pine tree-rings showed decreasing maximum densities from the period a.d. 975-1150 to a.d. 1450–1625. A concomitant change in the intra-annual growth characteristics was detected between these periods. The findings indicate that not only the trees growing near the species’ distributional limits are sensitive to large-scale climatic variations but also the trees growing in habitats remote from the timberline have noticeably responded to past climate changes.  相似文献   
59.
耿华美  付强  郭骏  王虹 《植物研究》2012,32(1):22-27
垂花青兰(Dracocephalum nutans Linn.)花蜜腺分布于子房基部的花托上,盘状蜜腺的上部裂成三小一大的四枚裂片,基部在膨大的花托外环绕一圈。蜜腺组织由分泌表皮、产蜜组织和维管束三部分组成,是典型的结构蜜腺;组织化学染色显示淀粉粒动态明显,因此又属淀粉蜜腺。在发育的过程中细胞液泡化动态明显,且淀粉粒和蛋白质具有明显的消长变化,蜜汁通过气孔器和表皮细胞的角质层泌出。  相似文献   
60.
BACKGROUND AND AIMS: Species having C4 photosynthesis belonging to the phosphoenolpyruvate carboxykinase (PEP-CK) subtype, which are found only in family Poaceae, have the most complex biochemistry among the three C4 subtypes. In this study, biochemical (western blots and immunolocalization of some key photosynthetic enzymes) and structural analyses were made on several species to further understand the PEP-CK system. This included PEP-CK-type C4 species Urochloa texana (subfamily Panicoideae), Spartina alterniflora and S. anglica (subfamily Chloridoideae), and an NADP-ME-type C4 species, Echinochloa frumentacea, which has substantial levels of PEP-CK. KEY RESULTS: Urochloa texana has typical Kranz anatomy with granal chloroplasts scattered around the cytoplasm in bundle sheath (BS) cells, while the Spartina spp. have BS forming long adaxial extensions above the vascular tissue and with chloroplasts in a strictly centrifugal position. Despite some structural and size differences, in all three PEP-CK species the chloroplasts in mesophyll and BS cells have a similar granal index (% appressed thylakoids). Immunolocalization studies show PEP-CK (which catalyses ATP-dependent decarboxylation) is located in the cytosol, and NAD-ME in the mitochondria, in BS cells, and in the BS extensions of Spartina. In the NADP-ME species E. frumentacea, PEP-CK is also located in the cytosol of BS cells, NAD-ME is very low, and the source of ATP to support PEP-CK is not established. CONCLUSIONS: Representative PEP-CK species from two subfamilies of polyphyletic origin have very similar biochemistry, compartmentation and chloroplast grana structure. Based on the results with PEP-CK species, schemes are presented with mesophyll and BS chloroplasts providing equivalent reductive power which show bioenergetics of carbon assimilation involving C4 cycles (PEP-CK and NAD-ME, the latter functioning to generate ATP to support the PEP-CK reaction), and the consequences of any photorespiration.  相似文献   
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