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951.
952.
Yves Rumpler 《Evolutionary anthropology》2002,11(Z1):145-149
953.
滇西南孟连曼信地区早石炭世磷结核中的放射虫 总被引:1,自引:0,他引:1
滇西南昌宁-孟连构造带下石炭统平掌组火山岩之硅质岩夹层中,存在大量结核,X衍射分析证明,这些结核全部为磷结核。其中一块磷结核经分析,获得放射虫化石7属9种(其中包括一未定种):Albaillella paradoxa Deflandre,Archocyrtium sp.,Robotium validum Cheng,Triaenosphaera sicarius Deflandre,Entactinia herculea Foreman,Entactinia parva Won,Astroentactinia multispinosa(Won),Entactinosphaera inusitata Foreman,Entactiosphaera palimbola Foreman,均属杜内期中期Albaillella paradoxa带。这些磷结核应该沉积在上升洋流形成的洋岛环境,而不是裂谷中。 相似文献
954.
We compared the morphology of all four members ofPelvetia andSilvetia (Fucaceae, Phaeophyta), with an emphasis on phylogenetic relationships.Silvetia is segregated fromPelvetia because it has two, longitudinally divided eggs in the oogonium. In contrast, the eggs of the genusPelvetia are transversally divided. A cladistic analysis, based on 17 morphological features, shows thatPelvetia is closely related toHesperophycus andPelvetiopsis, as are three species ofSilvetia. We can infer from the cladistic tree and biogeographic information that some silvetian ancestor populations from the northern
Pacific region likely evolved toS. babingtonii in northern Japan and then moved to Korea and California (USA), whereS. siliquosa andS. compressa, respectively, diverged. Our morphological study corroborates the DNA-based phytogeny and the ensuing taxonomy for the two
genera. These results demonstrate the necessity for systematically revising the family Fucaceae to emphasize egg development,
rather than egg number, in the oogonium, as a diagnostic character. 相似文献
955.
Gazza squamiventralis sp. nov. is described as the fifth species of the genus, based on the holotype and eight paratypes, 42–96 mm in standard
length, collected along the east coast of Africa, from Kenya to Mozambique. The species is similar to other congeners in general
appearance, differing clearly from them in having the ventrolateral surface of the body scaled anterior to a line from the
pectoral fin base to the pelvic fin origin (vs naked) and a smooth supraorbital ridge (vs finely serrated). Additionally,
the species differs from G. dentex, G. rhombea, and G. achlamys in having the dorsolateral surface of the body scaled anterior to a vertical through the tip of the posterior branch of the
supratemporal canal (vs corresponding region naked), and from G. minuta in having the first dorsal fin pterygiophore narrowly expanded anteriorly, with a concave margin (vs broadly expanded, with
a convex or linear margin), and a short antrorse extension of the first anal fin pterygiophore (vs long). A key to the five
species of the genus Gazza is provided.
Received: May 30, 2000 / Revised: September 16, 2000 / Accepted: January 16, 2001 相似文献
956.
957.
中国柽柳科(Tamaricaceae)花粉形态研究及其分类意义的探讨 总被引:17,自引:2,他引:15
研究观察了中国柽柳科(Tamaricaceae)4属27种植物的花粉形态。中国柽柳科植物花粉为三沟类型,无三拟孔沟类型,形态及外壁雕纹属间差异明显。根据花粉资料,探讨了属间的进化关系和分类地位及本科植物花粉外壁的演化途径。 相似文献
958.
The headshield of Monospilus dispar (Cladocera, Chydoridae, Aloninae) was characterized by the presence of a unique headpore. Scanning Electron Microscopy shows the occurrence of minute pores close to the main headpore. The intimate structure of the main headpore is formed by concentric lamellae. This new information leads to new considerations about phylogeny. 相似文献
959.
Takeo Horiguchi 《Phycological Research》1996,44(3):143-150
A new raphidophyte flagellate is described from the river mouth of the Daintree River, north-east Australia where there are extensive mangrove forests. The organism has two distinct phases: a club-shaped motile form, and a more or less spherical benthic non-motile form. The motile cell is metabolic and possesses 10–20 chloroplasts. The chloroplasts are imbricated, somewhat reminiscent of roofing tiles. A unique structure has been found at the posterior end of the cell. It is a tubular invagination, which consists of a single membrane supported by many small flattened vesicles. In addition, the structure is surrounded by many fibril-containing vesicles. The tubular invagination is different from both the contractile vacuoles and the pusules of dinoflagellates in both behavior and structure. Based on the possession of these unique features, it is concluded that the this mangrove flagellate should be described as a new species in a new genus and the name Haramonas dimorpha Horiguchi gen. et sp. nov. is proposed. 相似文献
960.
In Argentina, five genera and 14 species are recorded in the subfamilies Prostemmatinae and Nabinae: Hoplistoscelis sordidus Reuter, Lasiomerus constrictus Champion, Metatropiphorus alvarengai Reuter, Nabis argentinus Meyer-Dür, Nabis (Tropiconabis) capsiformis Germar, Nabis faminei Stål, Nabis paranensis Harris, Nabis punctipennis Blanchard, Nabis roripes Stål, Nabis setricus Harris, Nabis tandilensis Berg, Pagasa (Pagasa) costalis Reuter, Pagasa (Lampropagasa) fuscipennis Reuter and Pagasa (Pagasa) signatipennis Reuter. 相似文献