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排序方式: 共有187条查询结果,搜索用时 140 毫秒
181.
Bijan Dehgan 《American journal of botany》1982,69(8):1283-1295
Anatomical features of the petiole in several species of Jatropha L. (Euphorbiaceae) are presented as evidence in support of infrageneric relationships. A trilacunar 3-trace nodal pattern is typical for the genus. The vascular supply to the stipules is derived from the branching of the two peripheral leaf traces. The number of vascular bundles range from 11 through 9, 7, 5 and 3, and occur in a ring, as free traces, a medullated cylinder, or as U-shaped free traces. The reduction from nine to three bundles is correlated with the gross morphological features while 11, which occurs only in the section Peltatae (Pax) Dehgan & Webster, presents an increase. Reduction in the number of petiolar traces follows the evolutionary advancement of various taxa. This reduction in traces corresponds with south-north distribution of the species and consequential adaptation to colder and more arid climates in Central America and Africa. Smaller leaves, fewer primary veins and fewer vascular traces have resulted as a response to reduced need for water. Presence of dorsal (super-numerary) bundles which supply the petiolar glands in subgenus Jatropha (= Adenoropium Pax) is considered significant, since African taxa of the section (subsection Pubescentes Pax) have retained these bundles despite the loss of petiolar glands. The latter glands are prominent in the South American and Indian species. Sectional lines in the genus can, therefore, be drawn generally on the basis of numerical constancy and relative uniformity in the arrangement of petiolar traces. The continuity of vascular bundles from the stem into the petiole and variations of bundle arrangements are depicted in three-dimensional drawings. 相似文献
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183.
Nitrile metabolizing enzymes are of great industrial interest for the selective bio-transformation of nitriles and surface modification of synthetic polymers under mild reaction conditions. In the present work, isolated strain Amycolatopsis sp. IITR215 was cultivated in the bench top bioreactor for the recovery of maximum biomass of whole cell catalyst. Effect of different lyoprotectants was studied on nitrile metabolizing enzyme from Amycolatopsis sp. IITR215 in which sorbitol proved to be an efficient lyoprotectant. In physical and mechanical methods, only 30% activity was recovered while 85% activity was achieved in the enzymatic method using 2 g/l lysozyme. Very less activity was recovered during stationary phase when cells were grown in mineral base media containing 1 g/l yeast. Therefore, recovery of intracellular enzymes was enhanced by using different concentrations of sodium cholate and deoxycholate. 相似文献
184.
Bijan Zare Mohammad Nami Ahmad-Reza Shahverdi 《Biological trace element research》2017,178(2):171-179
The purpose of this study was to investigate whether the intakes of some kinds of vitamins and minerals are associated with periodontitis in a nationally representative sample of young adults. This study comprised 2049 young adults aged 19–39 years who took both periodontal examination and nutrition survey. The vitamin and mineral intakes were calculated from dietary intake data gained by complete one-day 24-h recall interviews, and the intake levels for each nutrient were classified by the Recommended Nutrient Intake (RNI) in Dietary Reference Intakes for Koreans and median values. Periodontitis was assessed using Community Periodontal Index (CPI). Multivariate logistic regression analyses were performed in a whole sample and subgroups with the strata of gender or smoking, following a complex sampling design. In analyses according to RNI, a lower intake of niacin was significantly associated with periodontitis in young adults (odd ratio [OR] 1.47, 95% confidential interval [CI] 1.09–2.00) and in its subgroup of women (OR 1.70; 95% CI 1.10–2.64) and current non-smokers (OR 1.75; 95% CI 1.22–2.51). Whereas, in analyses according to median intake values, there were significant associations of periodontitis with a lower intake of niacin in women (OR 1.58; 95% CI 1.02–2.46) and current non-smokers (OR 1.50; 95% CI 1.01–2.22), with lower intake of vitamin C in women (OR 1.66; 95% CI 1.04–2.64) and in current non-smokers (OR 1.49; 95% CI 1.04–2.14), with lower intake of iron in women (OR 1.85; 95% CI 1.11–3.07), and with lower intake of vitamin A marginally in women (OR 1.56; 95% CI 1.00–2.44). In young adults, periodonitis is significantly associated with the lower intakes of niacin, vitamin C, and iron, especially in women and current non-smokers. 相似文献
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186.
Soleymani Bijan Barzegari Ebrahim Mansouri Kamran Karami Keyvan Mohammadi Pantea Kiani Sarah Moasefi Narges Tabar Mehdi Sharifi Mostafaie Ali 《Molecular biology reports》2020,47(8):5943-5951
Molecular Biology Reports - Escherichia coli is a widely-used cell factory for recombinant protein production, nevertheless, high amount of produced protein is seen in aggregated form. The purpose... 相似文献
187.
Pooria Gill Bijan Ranjbar Reza Saber Khosro Khajeh Mehdi Mohammadian 《Journal of biomolecular techniques》2011,22(2):60-66
Cauliflower-like DNAs are stem-loop DNAs that are fabricated periodically in inverted repetitions from deoxyribonucleic acid phosphates (dNTPs) by loop-mediated isothermal amplification (LAMP). Cauliflower-like DNAs have ladder-shape behaviors on gel electrophoresis, and increasing the time of LAMP leads to multiplying the repetitions, stem-loops, and electrophoretic bands. Cauliflower-like DNAs were fabricated via LAMP using two loop primers, two bumper primers, dNTPs, a λ-phage DNA template, and a Bst DNA polymerase in 75- and 90-min periods. These times led to manufacturing two types of cauliflower-like DNAs with different contents of inverted repetitions and stem-loops, which were clearly indicated by two comparable electrophoresis patterns in agarose gel. LAMP-fabricated DNAs and natural dsB-DNA (salmon genomic DNA) were dialyzed in Gomori phosphate buffer (10 mM, pH 7.4) to be isolated from salts, nucleotides, and primers. Dialyzed DNAs were studied using UV spectroscopy, circular dichroism spectropolarimetry, and fluorescence spectrophotometry. Structural analyses indicated reduction of the molecular ellipticity and extinction coefficients in comparison with B-DNA. Also, cauliflower-like DNAs demonstrated less intrinsic and more extrinsic fluorescence in comparison with natural DNA. The overwinding and lengthening of the cauliflower-like configurations of LAMP DNAs led to changes in physical parameters of this type of DNA in comparison with natural DNA. The results obtained introduced new biomolecular characteristics of DNA macromolecules fabricated within a LAMP process and show the effects of more inverted repeats and stem-loops, which are manufactured by lengthening the process. 相似文献