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241.
Takehiro Masuzawa 《Journal of plant research》1985,98(1):15-28
The distribution of the meadow above the timberline and the structure of the forest at and below the timberline were investigated
on the southeast slope of Mt. Fuji. At the same time, soil profiles, water content and nutrients in the soil as related to
change in the structure of the plant community were examined to obtain the data regarding soil development with the course
of succession.
In the course of change in structure of forest, the plant community was classified into three types:Salix/Alnus dwarf forest,Larix forest andAbies/Picea forest. The change in the soil profile, from immature to mature soil, was observed. At the timberline the water content increased
rapidly from about 10% of bare land to about 25% of timberline. The nitrogen and carbon contents also increased at timberline
as compared with bare land.
Relationships between successional stage and soil development were clarified on the area from bare land to climax forest.
The present state of the timberline at the investigated area is discussed with reference to the course of change in forest
structure and soil development. It was concluded that the timberline of the investigated area is in the process of moving
to a higher altitude. This conclusion was reasonable in view of the factor of air temperature. 相似文献
242.
A. Lewandowski 《Plant Systematics and Evolution》1997,204(1-2):65-73
Thirteen populations ofLarix decidua subsp.decidua and subsp.polonica, and three populations ofL. sibirica were investigated by starch-gel electrophoresis. In the populations assayed 61 alleles at 17 loci were revealed. The allozyme data support the earlier observations about close relationships between these two larch species. Nei's genetic distances betweenL. decidua andL. sibirica were relatively small (D = 0.057), however, almost five times larger, on average, than those between populations of the same species. Results obtained in this study disagree withBobrov's hypothesis about the hybrid origin of the Polish larch and suggest a direct origin from the European larch. 相似文献
243.
Previous studies indicated that the high endogenous abscisic acid (ABA) content of hybrid larch ( Larix X leptoeuropaea ) somatic embryos was correlated with low germination frequency. However, when dried, the germination rate of the somatic embryos improved. Therefore, our present objective was to study the effect of desiccation on the levels of ABA and its glucose ester metabolite. Cotyledonary somatic embryos were subjected to drying treatments at 40 C under relative humidities of 98 and 59% for one week and the levels of both ABA and abscisic acid glucose ester (ABAGE) were followed by enzyme-linked immunoassay (ELISA). During desiccation at 98% relative humidity (RH) both ABA and ABAGE levels decreased in an irregular fashion. Regardless of RH, transient increases in ABA were observed that were paralleled by marked decreases in ABAGE. It is concluded that the desiccation of somatic embryos which leads to a decrease in ABA content, could explain the enhanced germination capacity of such embryos. 相似文献
244.
Structure and dynamics of the subalpine coniferous forest on Changbai mountain,China 总被引:7,自引:0,他引:7
The composition and structure of the subalpine coniferous forest communities on Changbai mountain, China, were studied. Two mixed-conifer forest types, indicated by different combinations of Picea jezoensis var. komarovii, Picea koraiensis, Abies nephrolepis, Pinus koraiensis, and one type dominated by Larix olgensis and Abies nephrolepis were sampled. The number of woody species become less towards the higher elevation, while the herb layer was richer in the upper part due to the lower crown density. The Larix-dominated stand was established in a large gap presented as a building phase, and its composition and structure were simpler than the other two types. The dynamics of the forest zone, which had a mosaic structure consisting of Picea- and Larix-dominated patches, is characterized by patches transforming from one to another. This mosaic structure, with patch interchanging, is defined as the climax of the forest zone. Larix played an important role in sustaining the coniferous forest communities as a gap revegetator and a conditioner for the regeneration of Picea and Abies. Windfall was considered to be a frequent disturbance factor which caused the vegetation to become more heterogeneous and offered opportunities for Larix to establish. 相似文献
245.
Elongation, rooting and acclimatization of micropropagated shoots from mature material of hybrid larch 总被引:4,自引:0,他引:4
Nicole Brassard Line Brissette Daniel Lord Sylvie Laliberté 《Plant Cell, Tissue and Organ Culture》1996,44(1):37-44
Factors were defined for elongation, rooting and acclimatization of micropropagated shoots ofLarix x eurolepis Henry initiated from short shoot buds of plagiotropic stecklings serially propagated for 9 years from an 8-year-old tree. Initiation and multiplication were on Schenk and Hildebrandt (SH) medium supplemented with 5 M 6-benzyladenine (BA) and 1 M indole-butyric acid (IBA). Stem elongation was obtained in 36% of the shoots on SH medium containing 0.5 M BA and 63% of the remaining non-elongated shoots initiated stem elongation after transfer on SH medium devoid of growth regulators. Rooting involved 2 steps: root induction on Campbell and Durzan mineral salts and Murashige and Skoog organic elements, both half-strength (CD-MS/2), supplemented with 1 M of both naphthaleneacetic acid (NAA) and IBA, and root elongation following transfer to CD-MS/2 medium devoid of growth regulators. Repeating this 2-step sequence yielded up to 67% rooted shoots. Acclimatization of plantlets ranged from 83% to 100%. Over 300 plants were transferred to the greenhouse; some showed plagiotropic growth. 相似文献
246.
Changes in abscisic acid content during maturation of hybrid larch somatic embryos ( Larix × leptoeuropaea ), were followed using an enzyme immunoassay (ELISA). In the presence of 60 μ M cis-trans (±)-ABA in the maturation medium, the cis-trans (±)-ABA level of the somatic embryos in planta increased during the maturation phase to reach a maximum value at week 5. Concomitantly, an extension of the period of maturation from 3 to 4 and 5 weeks resulted in a significant decrease in both germination and plantlet frequencies. As a consequence, we assume that it was the level of ABA in planta that was responsible for the inhibition. ABA acted in both a stimulatory and an inhibitory manner. If ABA promoted the obtention of high quality somatic embryos in large numbers, it also had a deleterious effect on the subsequent development, i.e. germination and plantlet recovery. The results stressed the importance of both the procedure and duration of maturation. 相似文献
247.
Vegetation structure of the treeline was studied on the southeastern slope of Mount Paektu (North Korea). Fifteen temporary
plots (20m×20m) were situated along the altitudinal transect. Seven square samples (phytosociological relevés 5 m×5 m) were
analyzed in each plot. Although the character of the vegetation was rather continuous altitudinally, five similar groups of
vegetation samples were distinguished by the TWINSPAN procedure. The distribution of samples in the classification showed
not only the effect of altitude but also the effect of competition between the tree and the shrub layers and other factors.
In the canonical correspondence analysis (CCA) ordination several environmental variables were used (such as altitude of each
plot, distance of each plot from the forest edge and the cover percentage of tree, shrub, herb and moss/lichen layers). The
variable ‘cover of tree layer’ had the strongest relation to the species data. Continuous changes of species richness along
the altitude were confirmed. Species richness decreased significantly with altitude. 相似文献
248.
249.
Summary The differentiation of the endodermis of mycorrhizal roots of Picea abies and Larix decidua was investigated by means of light and transmission electron microscopy and with fluorescence techniques. The initiation and differentiation of the Hartig net were recorded. Differences between the two tree species were found, as were differences between the two tree species and angiosperms. The Casparian band developed immediately after the origin of endodermal cells from the meristem in mycorrhizae of both tree species. In L. decidua only the primary endodermis was present in most mycorrhizal laterals. The secondary structure of the endodermis was restricted to main roots and proximal parts of larch mycorrhizae. In P. abies mycorrhizae, however, the secondary stage of the endodermis developed soon after the primary endodermis and was characterized by regular alternation of short, active passage cells and elongated, rapidly degenerating cells, the inner surface of which was covered by a thick suberin layer. Hartig net development started in P. abies short roots only after the differentiation of endodermis into the secondary stage, whereas in L. decidua, the Hartig net was already initiated at the primary endodermal stage. Differences were specific for tree species. 相似文献
250.
Response of radial growth to climate change for Larix olgensis along an altitudinal gradient on the eastern slope of Changbai Mountain,Northeast China 下载免费PDF全文
《植物生态学报》2016,40(1):24