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1.
Lysophosphatidylcholine is thought to be a characteristic component of the chromaffin granules in adrenal glands. By the use of a t.l.c. system that resolves minor phospholipids satisfactorily, this subcellular location was confirmed in the present study in bovine glands. However, phospholipid degradation was demonstrated in homogenates of the adrenal medulla and cortex under conditions similar to those of subcellular fractionation (incubation at 4°C for 90min). Phosphatidylethanolamine and cardiolipin were hydrolysed, but the concentration of lysophosphatidylcholine did not change, indicating that the latter was present in the medulla before this treatment. Attempts were made to decrease the time between death of the animal and the extraction of lipids. Lysophosphatidylcholine was easily demonstrable in lipid extracts of the dissected medulla and even in those of the whole bovine gland. For practical reasons it is not possible to decrease further the time lapse before extraction in the case of this animal. Adrenal glands were obtained from anaesthetized and untreated rabbits. These were frozen immediately in liquid N2 and the lipids were extracted. In a control experiment, the glands from rabbit were dissected and treated in the same manner as with those of ox, and then the lipids were extracted. No lysophosphatidylcholine was detected in the extracts from glands frozen in liquid N2 but lysophosphatidylcholine was observed in the controls. These results suggest that lysophosphatidylcholine is not a component of chromaffin granules, but is produced if the period between death of the animal and lipid extraction is unduly prolonged. To discover whether lysophosphatidylcholine affected the permeability barrier properties of chromaffin granules, sonicated liposomes of egg phosphatidylcholine alone or with lysophosphatidylcholine (15mol/100mol) were prepared. Both types were shown by electron microscopy to be largely made up of single bilayer vesicles. The exchange diffusion of [14C]dopamine was measured across their membranes. Both types of liposomes had similar capture volumes (0.5μl/μmol of phospholipid), and the activation energies of the exchange diffusion of dopamine were also similar (31kJ/mol). These results indicate that the presence of this proportion of lysophosphatidylcholine in chromaffin-granule membranes is not likely to influence their barrier properties towards catecholamines. 相似文献
2.
In this paper we present SNUAGE, a platform-as-a-service security framework for building secure and scalable multi-layered services based on the cloud computing model. SNUAGE ensures the authenticity, integrity, and confidentiality of data communication over the network links by creating a set of security associations between the data-bound components on the presentation layer and their respective data sources on the data persistence layer. SNUAGE encapsulates the security procedures, policies, and mechanisms in these security associations at the service development stage to form a collection of isolated and protected security domains. The secure communication among the entities in one security domain is governed and controlled by a standalone security processor and policy attached to this domain. This results into: (1) a safer data delivery mechanism that prevents security vulnerabilities in one domain from spreading to the other domains and controls the inter-domain information flow to protect the privacy of network data, (2) a reusable security framework that can be employed in existing platform-as-a-service environments and across diverse cloud computing service models, and (3) an increase in productivity and delivery of reliable and secure cloud computing services supported by a transparent programming model that relieves application developers from the intricate details of security programming. Last but not least, SNUAGE contributes to a major enhancement in the energy consumption and performance of supported cloud services by providing a suitable execution container in its protected security domains for a wide suite of energy- and performance-efficient cryptographic constructs such as those adopted by policy-driven and content-based security protocols. An energy analysis of the system shows, via real energy measurements, major savings in energy consumption on the consumer devices as well as on the cloud servers. Moreover, a sample implementation of the presented security framework is developed using Java and deployed and tested in a real cloud computing infrastructure using the Google App Engine service platform. Performance benchmarks show that the proposed framework provides a significant throughput enhancement compared to traditional network security protocols such as the Secure Sockets Layer and the Transport Layer Security protocols. 相似文献
3.
Mohammed A. EL‐Magd Shafika A. Elsayed Eman S. El‐Shetry Ahmed Abdelfattah‐Hassan Ayman A. Saleh Steve Allen Imelda McGonnell Ketan Patel 《Genesis (New York, N.Y. : 2000)》2019,57(11-12)
This study was conducted to check whether the three chick Early B‐cell Factor (Ebf) genes, particularly cEbf1, would be targets for Shh and Bmp signals during somites mediolateral (ML) patterning. Tissue manipulations and gain and loss of function experiments for Shh and Bmp4 were performed and the results revealed that cEbf1 expression was initiated in the cranial presomitic mesoderm by low dose of Bmp4 from the lateral mesoderm and maintained in the ventromedial part of the epithelial somite and the medial sclerotome by Shh from the notochord; while cEbf2/3 expression was induced and maintained by Bmp4 and inhibited by high dose of Shh. To determine whether Ebf1 plays a role in somite patterning, transfection of a dominant‐negative construct was carried out; this showed suppression of cPax1 expression in the medial sclerotome and upregulation and medial expansion of cEbf3 and cPax3 expression in sclerotome and dermomyotome, respectively, suggesting that Ebf1 is important for ML patterning. Thus, it is possible that low doses of Bmp4 set up Ebf1 expression which, together with Shh from the notochord, leads to establishment of the medial sclerotome and suppression of lateral identities. These data also conclude that Bmp4 is required in both the medial and lateral domain of the somitic mesoderm to keep the ML identity of the sclerotome through maintenance of cEbf gene expression. These striking findings are novel and give a new insight on the role of Bmp4 on mediolateral patterning of somites. 相似文献
4.
Mohd Ishtikhar Tajjali Ilm Chandel Aamir Ahmad Mohd Sajid Ali Hamad A. Al-lohadan Ayman M. Atta Rizwan Hasan Khan 《PloS one》2015,10(9)
Quaternary amine of diethylaminoethyl rosin ester (QRMAE), chemically synthesized biocompatible rosin based cationic surfactant, has various biological applications including its use as a food product additive. In this study, we examined the amorphous aggregation behavior of mammalian serum albumins at pH 7.5, i.e., two units above their isoelectric points (pI ~5.5), and the roles played by positive charge and hydrophobicity of exogenously added rosin surfactant QRMAE. The study was carried out on five mammalian serum albumins, using various spectroscopic methods, dye binding assay, circular dichroism and electron microscopy. The thermodynamics of the binding of mammalian serum albumins to cationic rosin modified surfactant were established using isothermal titration calorimetry (ITC). It was observed that a suitable molar ratio of protein to QRMAE surfactant enthusiastically induces amorphous aggregate formation at a pH above two units of pI. Rosin surfactant QRMAE-albumins interactions revealed a unique interplay between the initial electrostatic and the subsequent hydrophobic interactions that play an important role towards the formation of hydrophobic interactions-driven amorphous aggregate. Amorphous aggregation of proteins is associated with varying diseases, from the formation of protein wine haze to the expansion of the eye lenses in cataract, during the expression and purification of recombinant proteins. This study can be used for the design of novel biomolecules or drugs with the ability to neutralize factor(s) responsible for the aggregate formation, in addition to various other industrial applications. 相似文献
5.
Hassan A. Hemeg Ihab M. Moussa Sherin Ibrahim Turki M. Dawoud Jwaher H. Alhaji Ayman S. Mubarak Saleh A. Kabli Roua A. Alsubki Azza M. Tawfik Sherif A. Marouf 《Saudi Journal of Biological Sciences》2020,27(12):3221-3227
This study evaluates the antimicrobial effects of ethanolic extract of five herbal plants; Guava (Psidium guajava), Sage (Salvia officinalis), Rhamnus (Ziziphusspina Christi), Mulberry (Morusalba L.), and Olive (Oleaeuropaea L) leaves against several microbial population representing Gram positive, Gram negative and Mollicutes; S. aureus, E. coli, Pasteurella multocida, B. cereus, Salmonella Enteritidis and M. gallisepticum using standard agar disc diffusion technique and minimal inhibitory concentration (MIC). Different extracts reveal variable results against the microorganism under study. All extracts have no antibacterial potency for Mycoplasma gallisepticum except Psidium guajava. The results of minimal inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) of the extracts against the six bacteria ranged from 625 to 5000 μg/ml. The used herbal extract could inhibit the selected microorganism under study with variable minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). 相似文献
6.
7.
Laura A. Quimby Ayman S. Amer Sasha N. Zill 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2006,192(3):247-266
We studied the mechanisms underlying support of body load in posture and walking in serially homologous legs of cockroaches.
Activities of the trochanteral extensor muscle in the front or middle legs were recorded neurographically while animals were
videotaped. Body load was increased via magnets attached to the thorax and varied through a coil below the substrate. In posture,
tonic firing of the slow trochanteral extensor motoneuron (Ds) in each leg was strongly modulated by changing body load. Rapid
load increases produced decreases in body height and sharp increments in extensor firing. The peak of extensor activity more
closely approximated the maximum velocity of body displacement than the body position. In walking, extensor bursts in front
and middle legs were initiated during swing and continued into the stance phase. Moderate tonic increases in body load elicited
similar, specific, phase dependent changes in both legs: extensor firing was not altered in swing but was higher after foot
placement in stance. These motor adjustments to load are not anticipatory but apparently depend upon sensory feedback. These
data are consistent with previous findings in the hind legs and support the idea that body load is countered by common motor
mechanisms in serially homologous legs. 相似文献
8.
9.
Zakaria Mahmoud M. Derbala Safaa A. Salem Ayman E. EL-Agroudy Amgad E. El-Tantawy Fatma M. 《Molecular biology reports》2021,48(10):6857-6862
Molecular Biology Reports - Chronic kidney disease (CKD) is condition characterized by a gradual loss of kidney function, patient with CKD suffering from a variety of immune system defects. This... 相似文献
10.
Ayman F. Omar 《Journal of Plant Interactions》2016,11(1):101-107
Typical symptoms of phytoplasma such as whitening of the leaves, shortening of the stolons on Bermuda grass, variegated leaves, yellows, stunting, little leaves and yellows on Giant reed, Cooba and sand olive shrub were observed in Qassim province, Saudi Arabia, during the autumn season of 2015. When tested for phytoplasma by universal primers P1/P7 followed by R16mF2/R16mR2, products of approximately 1400?bp (as expected) were amplified from 16 plants with symptoms but not from symptomless plants. Based on sequencing, phylogenetic analysis and virtual restriction fragment length polymorphism patterns of the 16S rDNA F2nR2 fragments of seven Qassim phytoplasma isolates, bermuda grass isolates 170, 175 and 177, giant reed isolate 180, sand olive isolates 181 and 182 and cooba isolate 185, the associated phytoplasma was identified as a member of ‘Candidatus Phytoplasma cynodontis’ which belong to the 16SrXIV-A subgroup. The 16S rDNA gene sequences of seven Qassim phytoplasma isolates exhibited over 99.2% identity with members of ‘Ca. Phytoplasma cynodontis’ group of phytoplasmas. This is the first report of characterization of ‘Ca. phytoplasma cynodonties’ (16SrXIV) associated with Cynodon dactylon in Saudi Arabia and its new hosts, Dodonaea angustifolia, Arundo donax and Acacia salicia. 相似文献