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1.
Seeds of ten species of Cistaceae, Ericaceae and Poaceae were examinated to compare their responses to high temperatures and ash, simulating the direct effect of fire on germination. A variable response to these factors between families and within species from the same family was detected.In Cistaceae, heat treatment pre-sowing stimulated germination. In Ericaceae, germination was stimulated by thermic shock, but a wide range of response was detected (between all four species), from Erica ciliari, very sensitive, to Daboecia cantabrica and Calluna vulgaris which showed no significant response. The range of reaction shown by the species of this family suggest that the size of the seeds is directly related to the difference in response, at least in species with a similar structure. In Poaceae, germination was not found to be dependent upon thermic shock.The effect of ash varies in magnitude. Although it decreased the germination percentage in all species, in Avenula marginata (Poaceae) the effect was not statistically significant, whilst in Ericaceae, particularly in those showing the highest levels of germination in the control (C. vulgaris and E. umbellata), the effect is to inhibit germination completely. In respect to the effect of ash the families could be arranged in the order Ericaceae>Cistaceae>Poaceae.Complex interactions between various dormancy types and seed size could explain these results. In species which depend on physical dormancy temperature has an important role. When other dormancy type is dominant in the control of germination, the medium characteristics could have a relevant role on seed response. In addition, the seed-size could determine the threshold of tolerance to temperature. 相似文献
2.
Hideyuki Matsuura Kumiko Ohashi Hiroshi Sasako Noriko Tagawa Yuuko Takano Yumiko Ioka Kensuke Nabeta Teruhiko Yoshihara 《Plant Growth Regulation》2008,54(1):31-36
Root exudate of Vigna unguiculata was extracted from a soil system consisting of charcoal and vermiculite. Germination stimulating activity for Striga gesnerioides was found in extracts of the soil system, and an active compound was isolated. The chemical structure of the active ingredient
was determined to be (+)-4-O-acetylorobanchol, based on analysis of the spectral data of 1-D and 2-D NMR together with nuclear Overhauser effect (NOE)
experiments. Application of the active compound to the seeds of S. gesnerioides at a concentration of 0.35 × 10−9 mol/disk led to 69% germination. The germination observed with application of GR-24, a positive control, at 0.57 × 10−10 mol/disk was 80%. 相似文献
3.
《Fungal biology》2020,124(12):1058-1067
Fungal growth often appears in a surrounding where water and nutrients are scarce. The impact of this environment during sporogenesis on subsequent growth is often neglected.This study investigates the effect of water availability during sporogenesis on subsequent early growth. Therefore, a carbon-depleted substrate was constructed. Humidity is then the only parameter of interest. The water conditions during sporogenesis, and during subsequent growth, were varied. This is a stressing environment: no carbon source is present, and water provided solely via the vapour.The lag time, , and initial growth rate, , of the germ tubes were monitored.The effect of history on germination and initial growth depends on the of the environment. Only at low do spores produced at low have a smaller and higher compared to those grown at high . This result was remarkably pronounced when the substrate was also made hydrophobic: growth only occurred when spores were developed at low and placed in high .Spores grown on lowered attract more water. It is hypothesized that this attraction affects subsequent growth behaviour, and is the reason why growth on hydrophobic glass only prevails in the condition of high and lowered history.We demonstrate the influence of cultivation conditions on germination, which becomes more pronounced in a more desiccated environment. 相似文献
4.
J. Yamaguchi S. Itoh T. Saitoh A. Ikeda T. Tashiro Y. Nagato 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,98(1):32-38
β-Amylase deficiency in various cultivars of rice was examined at the molecular level. Using an antibody against β-amylase
purified from germinating seeds of rice, we were able to demonstrate the expression and organization of the β-amylase gene
in normal and deficient cultivars. Although β-amylase is a starch-hydrolyzing enzyme, as is α-amylase, the β-amylase protein/gene
is expressed differently from the α-amylase protein/gene; i.e. (1) β-amylase is synthesized only in aleurone cells, (2) the
enzyme production in the embryo-less half-seeds is not under hormonal control. We identified some cultivars of rice that are
deficient for β-amylase activity. We present new evidence that synthesis is blocked at the level of mRNA synthesis in the
deficient cultivars. The usefulness of β-amylase as a crop trait is also discussed.
Received: 8 May 1998 / Accepted: 5 June 1998 相似文献
5.
《Saudi Journal of Biological Sciences》2021,28(11):6500-6507
The nanoparticle has been reported to have severe effects and metabolic disorders in crops. Analysis of poisoning exposure to titanium dioxide is very important during the seed germination stage. Measuring the levels of water supply, reserve mobilization and redox metabolism with germination success is a prerequisite for understanding the TiO2 stress mechanism. These measurements are carried out using different methods, including germination tests, determination of growth parameters, analysis of reserve mobilization processes and redox activities under different stress conditions. The significant effects (P < 0.05) of TiO2 on seed germination were determined by analysis of variance (2 ways-ANOVA). We considered the effect of TiO2 dose (0 and 50 mg/L) and time of exposure (1,2,3,4 and 5 days). The results showed that TiO2 treatment significantly affected the germination rate (GR), the mean daily germination (MDG), the tissues dry weights, water supply, solute leakage, and induced oxidative stress and antioxidant enzyme activities. Oxidative and metabolic disturbances are among the major causes of the successful germination of pea seeds. 相似文献
6.
Pereskia aculeata and Pereskia grandifolia have been studied widely due to their high nutritional and therapeutic values. However, little is known about the biological requirements of their seeds for the various germination factors. Thus, this experiment aimed to evaluate the thermal effects on the germination of these species at the temperatures of 24 °C, 27 °C, 30 °C, 33 °C and 36 °C. After verification of the existence of differences in the performance of germination, a non-linear regression was carried out, relating the germination to temperature and identifying its point of maximum efficiency. We found that the lowest synchronization indexes of germination were observed close to 30 °C. The best germination response of the P. aculeata and P. grandifolia was observed at 30 °C and 33 °C, respectively, with greater germination strength and fewer days to attain 63.21% of germinations. The results obtained from the germination of P. aculeata and P. grandifolia can be described by the Weindull distribution model with three parameters, as proposed by Carneiro and Guedes (1992). 相似文献
7.
Matthew I. Daws Jennifer Davies Hugh W. Pritchard Neville A. C. Brown Johannes Van Staden 《Plant Growth Regulation》2007,51(1):73-82
We tested the applicability of the recently identified major germination cue from smoke (a butenolide 3-methyl-2Hfuro[2,3-c]pyran-2-one) on 18 weed species from non-fire prone environments. For the study species we compared the relative effectiveness
of alternating temperatures, KNO3, GA3, smoke water and the butenolide on germination percentage, germination rate and seedling mass. We found that while smoke
stimulated germination in a number of species it also had negative impacts on other species. In addition, the butenolide was
effective on the widest range of species in terms of enhancing germination percentage, rate and seedling mass. However, none
of the treatments, including butenolide were effective on all species. Our data demonstrate that butenolide may have wide
applicability as a germination and seedling growth stimulant irrespective of whether the species come from fire-prone habitats. 相似文献
8.
Changes in total nitrogen, soluble amino nitrogen, lipid and phytate contents, and in the activities of proteinase (pH 7.0), isocitrate lyase and phytase were followed in the endosperm, cotyledons, and axis during germination of fenugreek seeds and subsequent growth of the seedlings. The endosperm is comprised largely of cell-wall galactomannans: the majority of the seed total nitrogen, lipid and phytate (5%, 8%, 0.44% of seed dry weight respectively) is localised within the cotyledons as stored reserves. Germination is completed after 10–14 h from the start of imbibition, but the major reserves are not mobilised during the first 24 h. Then the total nitrogen content of the cotyledons starts to decrease and that of the axis increases; there is a concomitant accumulation of soluble amino nitrogen in both cotyledons and axis. An increase in proteinase activity in the cotyledons correlates well with the depletion of total nitrogen therein. Depletion of lipid and phytate reserves in the different seed tissues constitutes a late event, occurring after 50 h from the start of imbibition, and is coincident with the final disintegration of the endosperm tissue. The depletion of phytate and stored lipids is accompanied by an increase in phytase and isocitrate lyase activity. It appears that the products of lipid hydrolysis are converted by gluconeogenesis to serve as the major source of sugars for the growing axis after the endosperm galactomannan has been completely mobilised. 相似文献
9.
L. J. W. Gilissen 《Planta》1977,137(3):299-301
The volume of hydrated pollen grains of Petunia hybrida L. during swelling in germination medium increased three times. The volume of desiccated pollen grains increased only two times after transfer to the same medium. This difference in swelling ability is attributed to different rigidities of the pollen grain wall,ccaused by the different hydration states. The relationship between pollen grain swelling and germination metabolism with regard to relative humidity is discussed.Abbreviation RH
relative humidity 相似文献
10.
Light is known to regulate conservative germination strategies and the formation of seed banks. Although these strategies
are crucial to survival in tundra environments—especially for annuals—light requirements for germination in arctic–alpine
species are seldom investigated. Furthermore, environmental differences between arctic and alpine regions are expected to
lead to evolutionary divergence among conspecific populations in seed germination strategies. In this study, we report important
differences in germination light requirements among six arctic and alpine populations of the annual Koenigia islandica. Light had little effect on germination of the seeds from Iqaluit (Nunavut, Canada), Yukon (Canada), and Jasper (Alberta,
Canada), whereas the seeds from the most severe climates, Svalbard (Norway) and Colorado (USA), had strong light requirements.
Stratification of the seeds had little influence on their germination light requirements, with the exception of the population
from Dovre (Norway), in which it induced a strong light requirement. Possible adaptive explanations and some implications
of these observed germination patterns are discussed. 相似文献