全文获取类型
收费全文 | 342篇 |
免费 | 29篇 |
国内免费 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 16篇 |
2020年 | 15篇 |
2019年 | 18篇 |
2018年 | 9篇 |
2017年 | 10篇 |
2016年 | 9篇 |
2015年 | 18篇 |
2014年 | 15篇 |
2013年 | 30篇 |
2012年 | 33篇 |
2011年 | 31篇 |
2010年 | 14篇 |
2009年 | 15篇 |
2008年 | 19篇 |
2007年 | 15篇 |
2006年 | 16篇 |
2005年 | 18篇 |
2004年 | 18篇 |
2003年 | 12篇 |
2002年 | 3篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有372条查询结果,搜索用时 31 毫秒
81.
Ali Baghbanzadeh Mohammad Reza Hajinezhad Bahram Shohreh Reza Maleklou 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2010,196(3):221-226
The role played by adrenergic system in water intake, especially food intake, has long been known in mammals. In avian species,
there have been many experiments exploring the effects of the adrenergic system in different sites in the central nervous
system in meat- and egg-type poultry. This study was designed to examine the possible effects of intralateral hypothalamic
area (ILHy) microinjections of a beta-adrenergic agonist, isoproterenol, and a beta-adrenoceptor blocker, propranolol, on
food and water intake in 3-h food-deprived and 3-h water-deprived broiler cockerels. Our findings suggest that the β-adrenergic
system directly affects food especially water intake in broilers. Although isoproterenol significantly (P ≤ 0.05) decreased food intake for the first 15 min, it reduced food intake during the experiment. Isoproterenol reduced water
intake significantly (P ≤ 0.05), which was abolished by pretreatment with propranolol. It is proposed that β-adrenoceptors in LHy play a direct and
indirect role in the regulation of food especially water intake in broiler cockerels. 相似文献
82.
Somayeh Niknam Mohammad Ali Faramarzi Khosrou Abdi Mojtaba Tabatabaei Yazdi Mohsen Amini Hossein Rastegar 《World journal of microbiology & biotechnology》2010,26(1):119-123
Very limited studies have been done to investigate the algal biotransformation of codeine to its opioid derivatives. On the
other hand, microalgae have been recently introduced as potential tools for green synthesis of various organic compounds.
In the present work, the capability of biotransformation of codeine by a locally isolate strain of cyanobacterium, Nostoc muscorum, was evaluated. Incubation of the whole cells of Nostoc muscorum with codeine (I) under continuous light photoregime of 60 μmol photons/m2s at 25°C for 5 days gave rise to four transformation products. The bioproducts were separated by gas chromatography and identified
as 6-acetylcodeine (II), oxycodone (III), norcodeine (IV), morphine (V) and based on their mass spectra. Observed modifications included O-demethylation, N-demethylation, C6-acetylation, C14-hydroxilation,
Δ7-reduction, and C6-oxidation. The ability of N. muscorum to convert codeine to oxycodone (III) represents an uncommon pattern of codeine metabolism in microorganisms that may be of industrial importance. 相似文献
83.
Jason Pierson José Jesús Fernández Erik Bos Shoaib Amini Helmut Gnaegi Matthijn Vos Bennie Bel Freek Adolfsen José L. Carrascosa Peter J. Peters 《Journal of structural biology》2010,169(2):219-225
Cryo-electron tomography of vitreous cryo-sections is the most suitable method for exploring the 3D organization of biological samples that are too large to be imaged in an intact state. Producing good quality vitreous cryo-sections, however, is challenging. Here, we focused on the major obstacles to success: contamination in and around the microtome, and attachment of the ribbon of sections to an electron microscopic grid support film. The conventional method for attaching sections to the grid has involved mechanical force generated by a crude stamping or pressing device, but this disrupts the integrity of vitreous cryo-sections. Furthermore, attachment is poor, and parts of the ribbon of sections are often far from the support film. This results in specimen instability during image acquisition and subsequent difficulty with aligning projection images.Here, we have implemented a protective glove box surrounding the cryo-ultramicrotome that reduces the humidity around and within the microtome during sectioning. We also introduce a novel way to attach vitreous cryo-sections to an EM grid support film using electrostatic charging. The ribbon of vitreous cryo-sections remains in place during transfer and storage and is devoid of stamping related artefacts. We illustrate these improvements by exploring the structure of putative cellular 80S ribosomes within 50 nm, vitreous cryo-sections of Saccharomyces cerevisiae. 相似文献
84.
Hanieh Kamyab Shohreh Hejrati Mahnaz Khanavi Farshad Malihi Azadeh Mohammadirad Maryam Baeeri Hadi Esmaily Mohammad Abdollahi 《Central European Journal of Biology》2010,5(3):304-309
The present study was designed to explore the mechanism of action of walnut (the seed of Juglans regia) leaf and ridge on hepatic glucose metabolism in diabetic mice. Experimental diabetes was induced by intravenous administration of streptozotocin (60 mg/kg)and confirmed with an increase of blood glucose, 90–100% of the control, 72 hours later. Isolated extracts from walnut leaf and ridges were administered in a single effective dose of 400 mg/kg orally. Firstly, blood glucose was determined every 1 hour until 5 hours post administration of extracts. In the second experiment, the liver was surgically removed, 2 hours post treatment of diabetic animals with extracts, homogenized and used for measurement of key enzymes of glycogenolysis (glycogen phosphorylase, GP) and gluconeogenesis (phosphoenolpyruvate carboxykinase, PEPCK). Treatment by both leaf and ridge extracts decreased blood glucose and liver PEPCK activity and increased blood insulin and liver GP activity. It is concluded that walnut is able to lower blood glucose through inhibition of hepatic gluconeogenesis and secretion of pancreatic insulin. 相似文献
85.
Amini H Javan M Ahmadiani A 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2006,830(2):368-371
Sensitive and selective determination of valproic acid in plasma by high-performance liquid chromatography (HPLC) is usually achieved with pre-column derivatization. In the present work, the derivatization is omitted due to using a simple but highly selective plasma extraction procedure and an optimized chromatographic condition. Valproic acid and the internal standard octanoic acid were extracted from plasma samples with n-hexane under acidic condition followed by back-extraction into diluted triethylamine. Chromatography was performed on a CN column (250 x 4.6 mm, 5 microm) under isocratic elution with acetonitrile-40 mM aqueous sodium dihydrogen phosphate (30:70, v/v), pH 3.5. Detection was made at 210 nm and analyses were run at a flow-rate of 1 ml/min. The method was specific and sensitive with a quantification limit of 1.25 microg/ml and a detection limit of 0.1 microg/ml in plasma. The mean absolute recovery for valproic acid using the present plasma extraction procedure was 75.8%. The intra- and inter-day coefficient of variation and percent error values of the assay method were all in acceptable range. Calibration curves were linear (r>0.999) from 1.25 to 320 microg/ml in plasma. 相似文献
86.
Mohammad Ali Faramarzi Mojtaba Tabatabaei Yazdi Hadi Ghostinroudi Mohsen Amini Younes Ghasemi Hoda Jahandar Homeira Arabi 《Annals of microbiology》2006,56(3):253-256
Nostoc muscorum PTCC 1636 was examined for its ability to convert androst-4-en-3,17-dione (AD) and androst-1,4-dien-3,17-dione (ADD) to their 17-hydroxy related derivatives in BG-11 medium. Bioconversion procedures were carried out at 25 °C without shaking. The metabolites obtained were purified using chromatographic methods and characterized as testosterone and 1-dehydrotestosterone on the basis of their spectroscopic features. In both cases, the bioreaction characteristics observed were 17-carbonyl reduction. 相似文献
87.
Protein pattern changes in tomato under in vitro salt stress 总被引:2,自引:0,他引:2
F. Amini A. A. Ehsanpour Q. T. Hoang J. Sh. Shin 《Russian Journal of Plant Physiology》2007,54(4):464-471
The investigation of salt-induced changes in the proteome would highlight important genes because of a high resolution of
protein separation by two-dimensional gel electrophoresis (2-DE) and protein identification by mass spectrometry and database
search. Tomato (Lycopersicon esculentum Mill.) is a model plant for studying the mechanisms of plant salt tolerance. Seeds of tomato cv. Shirazy were germinated
on water-agar medium. After germination, seedlings were transferred to Murashige and Skoog nutrient medium supplemented with
0, 40, 80, 120, and 160 mM NaCl. After 24 days, leaf and root samples were collected for protein extraction and shoot dry
weight measurement. Alterations induced in leaf and root proteins under salt stress treatments were studied by one-dimensional
SDS-PAGE. Leaf proteins were also analyzed by 2-DE. With increasing salt concentration in the medium, shoot dry weight decreased.
SDS-PAGE showed induction of at least five proteins with mol wts of 30, 62, and 75 kD in roots and 38 and 46 kD in leaves.
On the 2-DE gel, more than 400 protein spots were reproducibly detected. At least 18 spots showed significant changes under
salt stress. Three of them corresponded to new proteins, while six proteins were up-regulated and five proteins were down-regulated
by salt stress. In addition, salinity inhibited the synthesis of four leaf proteins. Ten spots were analyzed by matrix-assistant
laser desorption/ionization-time of flight (MALDI-TOF), which led to the identification of some proteins, which could play
a physiological role under salt stress. The expression of new proteins(enoyl-CoA hydratase, EGF receptor-like protein, salt
tolerance protein, phosphoglycerate mutase-like protein, and M2D3.3 protein) under salt stress indicates that tomato leaf
cells respond to salt stress by changes in different physiological processes. All identified proteins are somehow related
to various salt stress responses, such as cell proliferation.
Published in Russian in Fiziologiya Rastenii, 2007, Vol. 54, No. 4, pp. 526–533.
The text was submitted by the authors in English. 相似文献
88.
89.
Yazdi MT Arabi H Faramarzi MA Ghasemi Y Amini M Shokravi S Mohseni FA 《Phytochemistry》2004,65(15):2205-2209
Hydrocortisone was converted in the culture of an isolated strain of the cyanobacterium Nostoc muscorum PTCC 1636 into some androstane and pregnane derivatives. The microorganism was, isolated during a screening program from soil samples collected from paddy fields of north of Iran. The bioproducts obtained were purified using chromatographic methods and identified as 11beta-hydroxytestosterone, 11beta-hydroxyandrost-4-en-3,17-dione and 11beta,17alpha,20beta,21-tetrahydroxypregn-4-en-3-one on the basis of their spectroscopic features. 相似文献
90.