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101.
水杨酸对黄瓜子叶表皮气孔开度的调节作用 总被引:1,自引:0,他引:1
以黄瓜品种中农203(Cucumis sativus L.cv.Zhongnong 203)幼苗为试材,采用SA溶液根部施用和子叶表皮浸泡两种方式,显微观测了不同外源水杨酸(Salicylic acid,SA)溶液处理对其子叶表皮气孔开度的影响,以探讨SA与气孔运动的关系.结果表明:SA子叶表皮浸泡或根部施用后,气孔运动的趋势是随着SA浓度增加而孔径逐渐变小,且SA磷酸缓冲液的作用效果与SA水溶液相似.随着处理时间的延长,气孔开度逐渐变小,且气孔开度与SA处理时间达极显著(r=-0.962**)或显著(r=-0.914*)负相关.溶液低pH值,增强了SA对气孔开度的抑制作用,且SA浓度越高作用越明显;0.1 mmol/L SA处理后,pH为8、7、6溶液的气孔开度抑制率分别为90.2%、93.8%和96.3%,即SA溶液对气孔开度的抑制率随着溶液pH降低而升高.可见,外源SA能够促进气孔关闭,其作用随着SA浓度升高、处理时间延长和溶液pH值降低而增强,相对于磷酸缓冲液,以蒸馏水作为溶剂的SA溶液促进气孔关闭的作用更大. 相似文献
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104.
Hyphomycete Paecilomyces fumosoroseus that is well known as saprophytic and entomopatogenic fungus was investigated for its mycoparasitism on the cucumber powdery mildew pathogen. Mycoparasitism was documented by using standard bioassay and SEM. Effects of mycoparasitism were evaluated in three types of experiments. Paecilomyces fumosoroseus was applied in the form of graded suspensions into a colony of powdery mildew on a leaf segment. Interaction between both fungi was observed as the percentage of colonized area vs. experimental time. In the second experiment, young cucumber plants were sprayed with a suspension of Paecilomyces fumosoroseus 24 h before inoculation of Sphaerotheca fuliginea. Pre-treatment with P. fumosoroseus reduced development and spreading of powdery mildew infection significantly 15 days post-inoculation in contrast to pre-treatments with sulfur fungicide and distilled water. The development of pure culture powdery mildew under determined experimental conditions was observed and compared with treated variants. In the third experiment, mildewed plants were treated with a suspension of P. fumosoroseus. The control treatments with sulfur fungicide and distilled water were tested. Effects of P. fumosoroseus on the dispersion of powdery mildew during a 21-day period were observed.P. fumosoroseus suppressed the development and spread of cucumber powdery mildew significantly during the time of the experiment. The mechanical and physical damages and disruptions of vegetative and fruiting structures of powdery mildew were recorded under light microscopy and S.E.M.Results were concluded in pursuance to differences between the natural behaviour and development of S. fuliginea on cucumber plants treated with P. fumosoroseus and non-treated plants. 相似文献
105.
del Valle LJ 《Development, growth & differentiation》2005,47(5):333-342
Sea urchin and sea star oocyte extracts contain proteolytic activities that are active against sperm basic nuclear proteins (SNBP). This SNBP degradation has been related to the decondensation of sperm chromatin as a possible model to male pronuclei formation. We have studied the presence of this proteolytic activity in Holothuria tubulosa (sea cucumber) and its possible relationship with sperm nuclei decondensation. The mature oocyte extracts from H. tubulosa contain a proteolytic activity to SNBP located in the macromolecular fraction of the egg‐jelly layer. SNBP degradation occurred both on sperm nuclei and on purified SNBP, histones being more easily degraded than protein Øo (sperm‐specific protein). SNBP degradation was found to be dependent on concentration, incubation time, presence of Ca2+, pH, and this activity could be a serine‐proteinase. Thermal denaturalization of the oocyte extracts (80°C, 10–15 min) inactivates its proteolytic activity on SNBP but does not affect sperm nuclei decondensation. These results would suggest that sperm nuclei decondensation occurs by a mechanism different from SNBP degradation. Thus, the sperm nuclei decondensation occurs by a thermostable factor(s) and the removal of linker SNBP (H1 and protein Øo) will be a first condition in the process of sperm chromatin remodeling. 相似文献
106.
24-表油菜素内酯对低氧胁迫下黄瓜根系抗氧化系统及无氧呼吸酶活性的影响 总被引:14,自引:0,他引:14
用营养液水培,研究了根际低氧胁迫下24-表油菜素内酯(EBR)对2个抗低氧能力不同的黄瓜品种根系中抗氧化系统及无氧呼吸酶活性的影响。结果表明,在低氧胁迫下,EBR处理显著提高了低氧胁迫下2品种黄瓜幼苗根系SOD、POD及ADH活性,降低了O2-·、H2O2和MDA含量、LDH活性及‘中农八号’根系PDC活性,而对‘绿霸春四号’根系PDC及2个品种CAT活性无明显影响,表明外源EBR处理通过促进低氧胁迫下根系中抗氧化酶和ADH活性的提高,降低LDH活性及ROS含量,增强植株抗低氧胁迫的能力。 相似文献
107.
Abscisic acid (ABA) is known to function in plant stress responses and seed dormancy, and much is known about its detailed mechanisms of signal transduction. Recent studies suggest that this hormone may also play important roles in sugar signaling and assimilate distribution during fruit development. However, little is known about the role of ABA in actively growing or differentiating fruits and other plant organs or tissues. To explore whether ABA functions during the early development of reproductive organs, we carried out ABA immunolocalization using monoclonal antibodies. The specific ABA accumulation pattern was verified by gas chromatography-mass spectrometry (GC-MS). ABA was not only detected in primordial cells of flower organs, but was also detected in nursing cells (e.g. tapetum and integuments), which function in supplying nutrition for germ cell development. These findings suggest that, in addition to its well-known function as a 'negative hormone', ABA may play some 'positive' roles during plant development, including possible involvement in the regulation of assimilate distribution. 相似文献
108.
Vanilloid receptors 1 (VRs1) expressed in a subpopulation of sensory neurons and responsible for processing of chemical and
thermal noxious stimuli were also shown to be expressed in several cerebral structures and to be involved in the regulation
of glutamatergic synaptic transmission. In this study, we started to investigate the possibility that VRs1 are also involved
in the regulation of GABA-ergic synaptic transmission. For this purpose, the effect of a VR1 agonist, capsaicin, on spontaneous
GABA-ergic inhibitory postsynaptic currents (IPSCs) was studied in hippocampal cell cultures using a patch-clamp technique.
It was found that capsaicin (10 μM) decreased both the frequency and amplitude of spontaneous IPSCs. This finding suggests
the involvement of VRs1 in the regulation of neuronal firing in some GABA-ergic interneurons and in the modulation of the
efficacy of GABA-ergic synaptic transmission. However, considering the direction of the effect (a decrease in the IPSC frequency)
and lack of its desensitization, the involvement of other receptor(s) also cannot currently be ruled out.
Neirofiziologiya/Neurophysiology, Vol. 38, No. 4, pp. 364–367, July–August, 2006. 相似文献
109.
Xuejun Yu Gaixia Li Dan Xu Xueliang Dong Xiuxiang Qi Youquan Deng 《Acta Physiologiae Plantarum》2006,28(1):9-11
The cucumber cotyledon greening bioassay for cytokinins was modified by using 95% acetone-ethanol instead of 80% acetone as
extraction solvent. The cotyledons were extracted directly with a 2:1 (v/v) acetone-ethanol solution in dark for 24 hours,
omitting the homogenization and centrifugation operations of the previous bioassay. The modified bioassay is more convenient
and especially useful in screening cytokinin-active substance from a large number of samples. 相似文献
110.
FENG ZHU HE TANG XIN LV JIAN CHENG HUANG‐FAN XIE HONG‐HUI LIN 《Plant, cell & environment》2012,35(11):1983-1997
The effects of potassium cyanide (KCN) pretreatment on the response of cucumber (Cucumis sativus L.) plants to salt, polyethylene glycol (PEG) and cold stress were investigated in the present study. Here, we found that KCN pretreatment improved cucumber seedlings tolerance to stress conditions with maximum efficiency at a concentration of 20 µM. The results showed that pretreatment with 20 µM KCN alleviated stress‐induced oxidative damage in plant cells and clearly induced the activity of alternative oxidase (AOX) and the ethylene production. Furthermore, the structures of thylakoids and mitochondria in the KCN‐pretreated seedlings were less damaged by the stress conditions, which maintained higher total chlorophyll content, photosynthetic rate and photosystem II (PSII) proteins levels than the control. Importantly, the addition of the AOX inhibitor salicylhydroxamic acid (1 mm ; SHAM) decreased plant resistance to environmental stress and even compromised the cyanide (CN)‐enhanced stress tolerance. Therefore, our findings provide a novel role of CN in plant against environmental stress and indicate that the CN‐enhanced AOX might contribute to the reactive oxygen species (ROS) scavenging and the protection of photosystem by maintaining energy charge homoeostasis from chloroplast to mitochondria. 相似文献