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991.
Abstract

The identification of introduced and native predators is important for many conservation studies within New Zealand. Carcasses of Hutton's shearwaters were collected over three field seasons, and where predation was probable, the bodies were autopsied. Paired bites identified stoats as the principal predator of Hutton's shearwater, but also revealed that a feral cat was present within the colony. Stoats killed their prey with a bite to the back of the neck or head, and commenced feeding on the neck or head. Despite the limited number of cat‐killed birds, cats appeared to feed on Hutton's shearwaters differently from stoats, starting on the breast muscles. Harriers and kea left sign that allowed birds killed or scavenged by these native birds to be distinguished from those killed by stoats or cats.  相似文献   
992.
Abstract

Aspects of larval feeding and tunnelling were described for seven species of the wood-boring genus Aenetus. The species were studied in Australia, New Caledonia, and New Zealand. A sequential pattern of larval feeding involving transfer from a fungal based diet to callus tissue in live trees, previously known for A. virescens, was confirmed for A. cohici and inferred for A. dulcis and A. paradiseus. A specialised “transfer” morph linking the two feeding stages in A. virescens was also confirmed for A. cohici and two unidentified species. The wood-boring habit involved entry into the host above ground level and the construction of a tunnel which extends into and then down the stem. Tunnels were often located on the lower surface of leaning branches or stems. Tunnel entrances were open to the host surface, but overlain by a silk- /frass web. Bark and underlying tissue were removed from around the tunnel entrance and a callus growth resulted, which the larva consumed. The evolutionary history of arboreal tunnelling in the Hepialidae was investigated using biogeographic analysis of generic distribution. It is argued that evolution and variation in arboreal tunnelling resulted from specialised recombinations of generalised ancestral characters. It is suggested that the study of arboreal tunnelling can provide a source of useful characters for systematic analysis of phylogenetic relationships within Aenetus. The potential systematic value of tunnel characters is illustrated for A. virescens.  相似文献   
993.
994.
In Nephrops norvegicus damage to the compound eye following exposure to excess light is not restricted to the photoreceptor layer, but is followed by morphological changes to the dioptric apparatus. Retinula cell damage results in the disruption of the cone cell processes leading to distal retraction of the crystalline tracts. The shape of the cones is also affected and there is a redistribution of the distal pigments. Within two months of exposure the reflective properties of subcorneal elements are changed and damage may be seen in the intact eye. A method based on external observations of the intact eye has been developed for quantitatively estimating the damage to the dioptric layer. The figures obtained were compared with estimates of retinula cell damage in the same eyes calculated using measurements from serially sectioned material. The estimation of ommatidial damage without recourse to sectioning should be of immediate practical benefit.  相似文献   
995.
The stomatopod Gonodactylus bredini is a predatory, aggressive crustacean possessing powerful raptorial appendages capable of inflicting serious injury on conspecifics. These weapons are readily employed during contests for cavities in coral rubble. In this study, we document the incidence of wounds in a population of G. bredini from Panama, determine the influence such injuries have on the behavior and fighting ability of individuals when competing for cavities, and examine associated costs of injury. A major consequence of injury in G. bredini is a severe reduction in fighting ability which in turn can alter the outcome of contests for cavities and the behaviors used by injured animals during such contests. A less immediate, but potentially costly consequence of injury due to increased chances of cannibalism and predation and lost breeding opportunities, is an acceleration in the onset of molt cycles in animals missing raptorial appendages.  相似文献   
996.
In the laboratory, the squid Loligo opalescens exhibits dominance behavior during spawning. A single dominant male keeps other male squid from coming near the egg mass he is guarding. Females are allowed to approach the egg mass. The dominant squid uses postural and color displays directed toward challenging males. Similar dominance behavior and displays have not been observed in natural spawns in the ocean.  相似文献   
997.
Species richness records from replicated deployments of baited remote underwater video stations (BRUVS) and unbaited remote underwater video stations (UBRUVS) in shallow (<1 m) and deep (>1 m) water were compared with those obtained from using fyke nets, gillnets and beach seines. Maximum species richness (14 species) was achieved through a combination of conventional netting and camera‐based techniques. Chanos chanos was the only species not recorded on camera, whereas Lutjanus argentimaculatus, Selenotoca multifasciata and Gerres filamentosus were recorded on camera in all three waterholes but were not detected by netting. BRUVSs and UBRUVSs provided versatile techniques that were effective at a range of depths and microhabitats. It is concluded that cameras warrant application in aquatic areas of high conservation value with high visibility. Non‐extractive video methods are particularly desirable where threatened species are a focus of monitoring or might be encountered as by‐catch in net meshes.  相似文献   
998.
An earlier report suggested that SS33410, structurally related to folimycin and bafilomycin A1, blocked secretion of the glycoprotein (G protein) of vesicular stomatitis virus (VSV) into the medium and, instead, G protein was accumulated intracellulary. To identify the inhibition site of SS33410 in intracellular protein transport, I have analyzed the oligosaccharide chain structure of the intracellularly accumulated G protein. In SS33410-treated VSV-infected cells, G protein oligosaccharide was suggested to have a composition of GlcNAc-Man5-GlcNAc2 as analyzed by Bio-Gel P-4 column chromatography following digestion with α-mannosidase, β-N-acetylhexosaminidase, and then with α-mannosidase. SS33410 specifically inhibited vacuolar-type ATPase (V-ATPase). These studies thus suggest that SS33410 blocks the intracellular protein transport before the step of trimming by mannosidase II, which is confined to the medial Golgi compartment.  相似文献   
999.
Phymatoderma is a branching burrow system consisting of tunnels filled with faecal pellets, and it has been interpreted as a product of a surface deposit‐feeding animal. Elemental analyses of Phymatoderma were conducted to reveal the specific feeding mode of its tracemaker, using samples from the Lower Jurassic epicontinental shelf deposits in the Dotternhausen section, southern Germany and from the Upper Pliocene continental slope deposits in the Shioura section, central Japan. Elemental compositions of the pelletal infill of Phymatoderma and its overlying mudstone from the Dotternhausen section show no significant difference, suggesting that the tracemaker was a non‐selective deposit feeder. In contrast, elemental compositions of the tuffaceous pellets of Phymatoderma from the Shioura section and its overlying volcanic ash show a difference in trends: CaO is significantly concentrated in the pellets. Because microfossils such as foraminifera and coccoliths are occasionally found in the tuffaceous pellets, CaO accumulation in the pelletal infill indicates the Phymatoderma‐producer that lived in the Pliocene slope setting selectively ingested particles with higher biomass of such microorganisms (or ingested microorganisms themselves) when feeding the surface sediments. Although two types of feeding modes of the tracemaker were recognized in Phymatoderma between different bathymetrical settings, each feeding mode seems to be an effective strategy to intake nutrients from the surface sediments and to reflect an adaptation of the tracemaker to the food contents in the surrounding substrate. This study suggests that geochemical composition of faecal pellets of trace fossils can be a useful indicator of grain‐selective/non‐selective deposit‐feeding strategies of ancient animals.  相似文献   
1000.
利用光镜对叉蕨科7属30种植物叶表皮形态特征进行详细观察研究。结果显示:(1)叉蕨科30种植物的叶上表皮和下表皮细胞形状均为不规则型,垂周壁式样为深波状或浅波状,具单晶或针晶;上表皮细胞的长宽比为1.62~4.0,下表皮细胞的长宽比为1.63~3.06。(2)在30种植物中共观察到7种气孔器类型,分别为:极细胞型、腋下细胞型、聚合极细胞型、聚腋下细胞型、不等细胞型、无规则四细胞型和不规则型,每种植物分别具有4~7种气孔器类型,均为下生型气孔;气孔长宽比为1.22~1.91,气孔密度为8~76个/mm2,气孔指数为3.9%~25.7%。(3)基于气孔器类型组成进行聚类分析,可将30种植物分成3个类群。(4)对叶表皮形态特征分析认为,轴脉蕨属应介于叉蕨属和肋毛蕨属之间,且与叉蕨属关系更近;叉蕨属的范畴还有待进一步研究;支持将肋毛蕨属从叉蕨科中分离出来置于鳞毛蕨科,但不支持黄腺羽蕨属归入鳞毛蕨科。  相似文献   
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