首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   183篇
  免费   13篇
  2024年   1篇
  2023年   4篇
  2022年   3篇
  2021年   2篇
  2020年   6篇
  2019年   2篇
  2018年   7篇
  2017年   9篇
  2016年   4篇
  2015年   8篇
  2014年   9篇
  2013年   11篇
  2012年   21篇
  2011年   10篇
  2010年   14篇
  2009年   10篇
  2008年   8篇
  2007年   8篇
  2006年   9篇
  2005年   7篇
  2004年   7篇
  2003年   11篇
  2002年   3篇
  2001年   2篇
  2000年   2篇
  1999年   2篇
  1997年   2篇
  1995年   1篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1988年   1篇
  1986年   1篇
  1985年   3篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1977年   1篇
  1938年   1篇
排序方式: 共有196条查询结果,搜索用时 15 毫秒
1.
Summary The administration of 2 bromo--ergocryptine, to reduce serum prolactin decreased the activity of cytosolic P-enolpyruvatc carboxykinase (GTP) (EC4.1.1.32) about 50% in both liver and mammary gland of lactating animals. Adrenalectomy had similar effects to those of bromo-a-ergocryptine. In contrast, there was a 50% increase in enzyme activity in the mammary gland of diabetic, lactating rats and a 10-fold increase in liver as compared with normal rats. P-enolpyruvate carboxykinase activity in mammary gland as liver is coordinately regulated by prolactin, glucocorticoids and insulin.  相似文献   
2.
3.
Aqueous protein extracts from 30 Brazilian marine algae were examined for haemagglutinating activity using native and enzyme-treated rabbit, chicken, sheep and human erythrocytes. Most extracts agglutinated at least one of the blood cells used. Sheep and rabbit erythrocytes were more suitable for detection of the agglutinating activity. The minimum protein concentration necessary to produce positive agglutination was usually lower with enzyme-treated erythrocytes than native ones. The five algal protein extracts showing the greatest haemagglutination titre were tested for sugar-binding specificity. Only the activity present in the green alga Cauler pacupressoides was inhibited by simple sugars and not by the glycoproteins tested. The activity of the other four extracts was inhibited by at least one of the glycoproteins utilised. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
4.
Capsule Some males brought building materials to nests and females who were paired with such males laid heavier clutches.  相似文献   
5.
In this work, the long‐term effects of transient chemical oxygen demands (COD) concentrations over the performance of a microbial fuel cell were studied. From the obtained results, it was observed that the repetitive change in the COD loading rate during 12 h conditioned the behavior of the system during periods of up to 7 days. The main modifications were the enhancement of the COD consumption rate and the exerted current. These enhancements yielded increasing Coulombic efficiencies (CEs) when working with COD concentrations of 300 mg/L, but constant CEs when working with COD concentrations from 900 to 1800 mg/L. This effect could be explained by the higher affinity for the substrate of Geobacter than that of the nonelectrogenic organisms such as Clostridia. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:883–890, 2016  相似文献   
6.
The action of substances with non-permeable cryoprotectant potential, besides glucose, has not yet been studied for the species Prochilodus brevis. The objective of this work was to evaluate the action of four non-permeable cryoprotectants on this species sperm cryopreservation. Five pools were cryopreserved in a solution of 5% glucose and 10% dimethyl sulfoxide (Me2SO) associated or not (control) with cryoprotectants egg yolk (5, 10 or 12%), soy lecithin (2.5, 7.5 or 10%), sucrose (5, 10 or 20%) and lactose (5, 8 or 15%). After thawing, samples were evaluated for sperm kinetics (total motility, motility duration, velocities, and wobble - WOB), morphology and membrane and DNA integrity. The treatments containing egg yolk improved significantly (P<0.05) results when compared the control for the membrane integrity parameter. When compared to other treatments, egg yolk, at any concentration, presented higher results (P<0.05) for membrane integrity, total motility, curvilinear velocity (VCL) and average path velocity (VAP) parameters. Egg yolk also showed the best results for WOB, but it did not differ from 5% and 8% lactose and 5% and 20% sucrose. Soy lecithin had the lowest percentages of morphologically normal sperm (P<0.05), while the other treatments did not differ from each other. There was no difference regarding DNA integrity data. Thus, 5% egg yolk is indicated as a non-permeable cryoprotectant for P. brevis, in association with 5% glucose and 10% Me2SO.  相似文献   
7.
In the course of a trip to Ecuador I had the opportunity of collecting topotypic specimens of the following nominal species of pulmonate molluscs: Biomphalaria cousini Paraense, 1966; Planorbis equatorius Cousin, 1887; P. canonicus Cousin, 1887; Lymnaea cousini Jousseaume, 1887 and P. boetzkesi Miller, 1879. Additional findings were: Helisoma trivolvis (Say, 1817), Biomphalaria peregrina (Orbigny 1835), Drepanotrema anatinum (Orbigny, 1835), D. kermatoides (Orbigny, 1835), D. lucidum (Pfeiffer, 1839), D. surinamense (Clessin, 1884), Lymnaea columella Say, 1817 and Physa acuta Draparnaud, 1805. P. boetzkesi and P. canonicus are considered junior synonyms of Gyraulus hindsianus (Dunker, 1848) and Biomphalaria peregrina (Orbigny, 1835), respectively.  相似文献   
8.
A new species of planorbid mollusc, Plesiophysa dolichomastix (Greek dolichos = long, mastix = flagellum), collected from Lagoa da Pedra, municipality of Santa Rosa, state of Goiás, Brazil (15 degrees 01'S, 47 degrees 13'W) is described. It is indistinguishable by the shell characters from the five congeneric species described so far: P. striata (Orbigny, 1841), P. granulata ("Shuttleworth" Sowerby, 1873), P. guadeloupensis ("Fischer" Mazé, 1883), P. ornata (Haas, 1938) and P. hubendicki Richards & Ferguson, 1962. It differs from the anatomically studied species in the following characters: about 50 ovotestis diverticula, against 12 in granulata, 100 in ornata, unstated in hubendicki; and length of flagella - about as long as the penial complex -, against about 1/3 to 1/6 in the other three.  相似文献   
9.
Chronic Obstructive Pulmonary Disease (COPD) is a common lung disease characterized by breathing difficulty as a consequence of narrowed airways. Previous studies have shown that COPD is correlated with neutrophil infiltration into the airways through chemotactic migration. However, whether neutrophil chemotaxis can be used to characterize and diagnose COPD is not well established. In the present study, we developed a microfluidic platform for evaluating neutrophil chemotaxis to sputum samples from COPD patients. Our results show increased neutrophil chemotaxis to COPD sputum compared to control sputum from healthy individuals. The level of COPD sputum induced neutrophil chemotaxis was correlated with the patient’s spirometry data. The cell morphology of neutrophils in a COPD sputum gradient is similar to the morphology displayed by neutrophils exposed to an IL-8 gradient, but not a fMLP gradient. In competing gradients of COPD sputum and fMLP, neutrophils chemotaxis and cell morphology are dominated by fMLP.  相似文献   
10.
Bovine vaccinia (BV) is a zoonosis caused by Vaccinia virus (VACV), which affects dairy cattle and humans. Previous studies have detected the presence of viable virus particles in bovine milk samples naturally and experimentally contaminated with VACV. However, it is not known whether milk contaminated with VACV could be a route of viral transmission. However, anti-Orthopoxvirus antibodies were detected in humans from BV endemic areas, whom had no contact with affected cows, which suggest that other VACV transmission routes are possible, such as consumption of contaminated milk and dairy products. Therefore, it is important to study the possibility of VACV transmission by contaminated milk. This study aimed to examine VACV transmission, pathogenesis and shedding in mice orally inoculated with experimentally contaminated milk. Thirty mice were orally inoculated with milk containing 107 PFU/ml of VACV, and ten mice were orally inoculated with uncontaminated milk. Clinical examinations were performed for 30 consecutive days, and fecal samples and oral swabs (OSs) were collected every other day. Mice were euthanized on predetermined days, and tissue and blood samples were collected. Nested-PCR, plaque reduction neutralization test (PRNT), viral isolation, histopathology, and immunohistochemistry (IHC) methods were performed on the collected samples. No clinical changes were observed in the animals. Viral DNA was detected in feces, blood, OSs and tissues, at least in one of the times tested. The lungs displayed moderate to severe interstitial lymphohistiocytic infiltrates, and only the heart, tonsils, tongue, and stomach did not show immunostaining at the IHC analysis. Neutralizing antibodies were detected at the 20th and 30th days post infection in 50% of infected mice. The results revealed that VACV contaminated milk could be a route of viral transmission in mice experimentally infected, showing systemic distribution and shedding through feces and oral mucosa, albeit without exhibiting any clinical signs.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号