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101.
By pretreating etiolated cucumber cotyledons with kinetin in the dark, it was observed that the plastids isolated from such tissues were 400% more active in the conversion of δ-aminolevulinic acid into protochlorophyllide, than plastids prepared from water-treated controls. The experimental evidence is consistent with the hypothesis that (a) the kinetin dark-pretreatment of the etiolated tissue, uncouples the joint biosynthesis of prothylakoids and protochlorophyll and results in the accumulation of excess prothylakoid membranes poorly supplied with protochlorophyllide (b) upon isolation of the plastids and incubation with δ-aminolevulinic acid, the latter is very rapidly converted into membrane-bound protochlorophyllide.  相似文献   
102.
We investigated the effects of cisplatin (cisPt) in normal PC Cl3 and in transformed and tumourigenic PC E1Araf cells. cisPt cytotoxicity was higher in PC Cl3 than in PC E1Araf cells. In both cell lines, cisPt provoked the ERK1/2 phosphorylation; this was unaltered by G?6976, a conventional PKC inhibitor, whilst it was blocked by low doses (0.1 microM) or high doses (10 microM) of GF109203X, an inhibitor of all PKC isozymes, in PC Cl3 and in PC E1Araf cells, respectively. In PC E1Araf, the cisPt-provoked ERK phosphorylation was also blocked by the use of a myristoylated PKC-zeta pseudosubstrate peptide. Conversely, in PC Cl3 the cisPt-provoked ERK phosphorylation was blocked by the use of rottlerin, a PKC-delta inhibitor. Results show that cisPt activates both PKC (the -delta and the -zeta isozymes in PC Cl3 and in PC E1Araf cells, respectively) and ERK in association with prolonged survival of thyroid cell lines.  相似文献   
103.
The biophysical properties of a series of glycosyl dialkyl- and diacyl-glycerols bearing unsaturated or chiral methyl branched chains in the tail, and di- and trisaccharide carbohydrate headgroups are described. Thermotropism was investigated by polarising microscopy, the lyotropism was investigated by small angle X-ray diffraction and by the contact preparation method, and the gel to liquid crystalline phase transition by FT-IR-spectroscopy. The compounds displayed thermotropic Smectic A (SmA), cubic and columnar phases, whereas in the lyotropic phase diagram lamellar, hexagonal and cubic phases are found. The introduction of unsaturated or methyl branched chains leads to liquid crystallinity at ambient temperature. The difference between the 1,3-oleyl-glycerol maltoside and the corresponding 1,2-oleoyl-glycerol maltoside is small.  相似文献   
104.
Arie L. Gutman 《Phytochemistry》1984,23(12):2773-2775
[4-14C]-δ-Aminolaevulinic acid (δ-ALA) was employed to study the specificity of δ-ALA incorporation into chlorophyll in etiolated Euglena gracilis. Degradation of chlorophyll a to acetate and propionate, obtained from ring B, indicated that, although some of the radioactivity was incorporated, it did not result from incorporation of intact δ-ALA.  相似文献   
105.
Irrespective use of chemical pesticides has led, over the last decades, to several problems such as soil, water and food sources pollution, and generation of a selective pressure causing the emergence of pest resistance. Consequently, researchers have been focusing more on the use of biological control as an alternative strategy. Bacillus thuringiensis (Bt) is one of the most widely studied bacteria in industrial biotechnology and commercialized as an environmentally sustainable biopesticide. Therefore, a huge interest has been allocated for research on this bacterium and several scientific studies have been published on the issue. In this review, we tried to evaluate the scientific production over the last thirty years, for the first time, in terms of number and geographical origin, focusing particularly on B. thuringiensis kurstaki (Btk). It is worth emphasizing that the Btk process engineering involving factors affecting growth, sporulation and toxin formation yields by Bt has not been fully investigated in previous reviews. To this end, the second section of this review provided an updated survey about these conditions, such as nutritional requirements, culture media and fermentation technologies. Relevant information was collected in comparative tables that could be very useful for the scientific community interested in Btk-based biopesticides.  相似文献   
106.
Abstract

Studying the mycological flora of paddy and grass-fields we had the opportunity to isolate some species of Eutotiaceae which are of particular interest. Three species were not yet known in Italy and only one was found in a soil of mountain pasture. The last one is also common in paddy fields. One of the isolated species was a Pseudoeurotium van Beyma, ascomycete with asci containing 16 ascospores, not identifiable with the systematically related species described as Pseudoeurotium indicum (Chattopadhyay and Das Gupta) Chattopadhyay from « oryzetis » in India and Pseudoeurotium multisporum (Saito and Minoura) Stolk in Japan. Some distinct morphological differences exist between our isolates and P. multisporum; but they differ only faintly from P. indicum: that is our isolates have pedicellate asci. Therefore we suggest the new variety: Pseudoeurotium indicum (Chattopadhyay and Das Gupta) Chattopadhyay var. orizetorum nobis. Three species of the genus Emericellopsis van Beyma: E. minima Stolk, E. terricola van Beyma and E. humicola (Cain) Cain were also isolated. The first one from the paddy-fields and the last two, not yet described in Italy, from grass fields. The possible relationship between E. minima Stolk arid E. pusilla Mathur, Sukapure and Thirumalachar has been discussed.  相似文献   
107.
108.
Abstract

The inhibition of δ- and η-class carbonic anhydrases (CAs; EC 4.2.1.1) was poorly investigated so far. Only one δ-CA, TweCA from the diatom Thalassiosira weissflogii, and one η-CA, PfCA, from Plasmodium falciparum, have been cloned and characterised to date. To enrich δ- and η-CAs inhibition profiles, a panel of 22 phenols was investigated for TweCA and PfCA inhibition. Some derivatives showed effective, sub-micromolar inhibition of TweCA (KIs 0.81–65.4?µM) and PfCA (KIs 0.62–78.7?µM). A subset of compounds demonstrated a significant selectivity for the target CAs over the human physiologically relevant ones. This study promotes the identification of new potent and selective inhibitors of TweCA and PfCA, which could be considered as leads for finding molecular probes in the study of carbon fixation processes (in which TweCA and orthologue enzymes are involved) or drug candidates in the treatment of malaria.  相似文献   
109.
生长在超干旱环境下的3种相思树种表现出异常低的叶片、树枝、树干、根中δ13C含量 在植物生理生态学中,叶片中碳13(13C)含量负值较少(富集),表明叶片处于通过气孔的气体交换减少,比如在干旱胁迫下。此外,与叶片相比,13C在非光合组织中的负值也较少。然而,对从叶片(光合器官)到树枝、树干和根(非光合器官)中的δ 13C数值的关系知之甚少,特别是缺少在关联密切的多个树种间或者不同器官间,以及对生长在极端高温和干旱胁迫下的树木中进行测定。本研究测定了3种近缘沙漠相思树种(Acacia tortilis、A. raddiana和A. pachyceras)从叶片到根的13C含量。我们在以色列南部成树的叶片组织中测定了δ 13C含量。与此同时,在试验果园进行了为期7年的3个水平的灌溉试验。在试验结束时,测定了叶片、树枝、树干和根的生长参数和δ 13C含量。研究结果表明,叶片组织中δ 13C含量约为−27‰,其同位素贫化程度远超过生长在地球上最干燥和最热环境中的沙漠树种的预期值。在不同的相思树种和不同器官中,所有灌溉水平处理中的δ 13C含量并没有富集(−28‰到ca. −27‰),证实了在成熟相思树中的测定结果。在不同器官中,叶片δ 13C含量与树枝和根的δ 13C含量异常相似,甚至比树干的δ 13C含量负值更少。高度贫化的叶片δ 13C表明,尽管这些树木生长在极端干燥的生境中,但其气孔气体交换较高。非光合组织中缺乏δ 13C富集可能与叶片和异养组织生长的季节耦合有关。  相似文献   
110.
目的对肿瘤浸润性γδT细胞(γδTIL)CDR3δ1区进行序列分析。方法用固相包被抗体,体外扩增14例肿瘤组织(胃癌、肾癌、卵巢癌、膀胱癌、食管癌、肺癌、嗜铬细胞瘤)和2例肿瘤腹水(浆乳癌)的γδ肿瘤浸润淋巴细胞(tumor infiltration lymphocytes,γδTIL),RT-PCR法扩增CDR3δ1基因片段,测序分析其序列特征。结果 16例γδTIL的CDR3δ1确实存在优势序列,不完全相同。其中4例胃癌来源的γδTIL中3例的CDR3δ1优势序列相同,3例食管癌来源的γδTIL中2例的CDR3δ1优势序列相同。结论体外扩增培养的γδTIL的TCR CDR3δ1序列具有相对优势特征。不同个体的同种组织来源的γδTIL的CDR3δ1优势序列趋于相同。  相似文献   
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