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71.
Shawn E. McGlynn Shane S. Ruebush Anatoli Naumov Lauren E. Nagy Alexandra Dubini Paul W. King Joan B. Broderick Matthew C. Posewitz John W. Peters 《Journal of biological inorganic chemistry》2007,12(4):443-447
The in vitro activation of the [FeFe] hydrogenase is accomplished by combining Escherichia coli cell extracts containing the heterologously expressed inactive HydA with extracts in which hydrogenase-specific maturation
proteins HydE, HydF, and HydG are expressed in concert. Interestingly, the process of HydA activation occurs rapidly and in
the absence of potential substrates, which suggests that the hydrogenase accessory proteins synthesize an H-cluster precursor
that can be quickly transferred to the hydrogenase enzyme to affect activation. HydA activity is observed to be dependent
on the protein fraction containing all three accessory proteins expressed in concert and cannot be accomplished with addition
of heat-treated extract or extract filtrate, suggesting that the activation of the hydrogenase structural protein is mediated
by interaction with the accessory assembly protein(s). These results represent the first important step in understanding the
process of H-cluster assembly and provide significant insights into hydrogenase maturation.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
72.
73.
Ames H Mingolla E Sohail A Chandler B Gorchetchnikov A Leveille J Livitz G Versace M 《IEEE pulse》2012,3(1):47-50
The researchers at Boston University (BU)'s Neuromorphics Laboratory, part of the National Science Foundation (NSF)-sponsored Center of Excellence for Learning in Education, Science, and Technology (CELEST), are working in collaboration with the engineers and scientists at Hewlett-Packard (HP) to implement neural models of intelligent processes for the next generation of dense, low-power, computer hardware that will use memristive technology to bring data closer to the processor where computation occurs. The HP and BU teams are jointly designing an optimal infrastructure, simulation, and software platform to build an artificial brain. The resulting Cog Ex Machina (Cog) software platform has been successfully used to implement a large-scale, multicomponent brain system that is able to simulate some key rat behavioral results in a virtual environment and has been applied to control robotic platforms as they learn to interact with their environment. 相似文献
74.
75.
The aim of this study was to determine the time taken for complete uterine involution in Bulgarian Murrah buffaloes following normal parturition and oxytocin stimulated milking; and to establish the time course of the change in size of the uterine horns, the cervix and caruncles between parturition and involution by means of ultrasonography. There were 17 animals in the study aged 3-6 years and average parity of 2.17 ± 0.18. They were administered 20 IU oxytocin 15 min before each milking. Rectal palpation and transrectal ultrasonography were performed at 3 d intervals from Days 1 to 34 post partum. The involution of the non-gravid and gravid uterine horns, and the cervix was complete by Days 22 and 25 post partum when their diameters were 2.7 ± 0.4 cm, 2.8 ± 0.3 cm and 3.12 ± 0.4 cm, respectively. Caruncles underwent rapid regression until Day 10 post partum. It was not possible to determine the dimensions of the caruncles after that time. The cumulative percentage of animals whose uterus was located in the pelvic cavity increased from 24% at Day 10 post partum to 100% at Day 34 post partum. The combination of rectal palpation and transrectal ultrasonography provided a reliable method of evaluating changes in the uterus over time and determining the time of uterine involution. The present study showed that complete uterine involution, with the uterus located in the pelvic cavity, was achieved by Day 34 after parturition in all 17 Bulgarian Murrah buffaloes treated with oxytocin before milking. 相似文献
76.
77.
Fiore A Mannina L Sobolev AP Salzano AM Scaloni A Grgurina I Fullone MR Gallo M Swasey C Fogliano V Takemoto JY 《FEMS microbiology letters》2008,286(2):158-165
The production of secondary metabolite lipopeptides by ice-nucleating Pseudomonas syringae strain 31R1 was investigated. Pseudomonas syringae strain 31R1 is a rifampicin-resistant derivative of P. syringae no. 31 used for the commercial production of snow. It is shown that P. syringae strain 31R1 produces antifungal lipodepsipeptides, syringomycins E and G, and, in addition, a novel and unique lipopeptide, peptin31. Spectroscopic and spectrometric analyses revealed that peptin31 is a linear undecalipopeptide with sequence identities to N- and C-terminal portions but lacking 11 amino acids of known lipodepsipeptide syringopeptin SPPhv. Peptin31 displayed antifungal activities against Rhodotorula pilimanae, Rhizoctonia solani, and Trichoderma harzianum and also hemolytic and antibacterial activities. Extracts of P. syringae strain 31R1 grown in medium with chloride were fungicidal, but not when grown without chloride. The latter extracts lacked peptin 31 and contained des-chloro forms of syringomycins E and G with low antifungal activities. Thus, the three lipopeptides account for the fungicidal properties of P. syringae 31R1 extracts. The occurrence of these bioactive metabolites should be considered when P. syringae no. 31 and its derivatives are used in products for making artificial snow. 相似文献
78.
Alexander L. Lagonenko Veronika S. Komardina Yevgeny A. Nikolaichik Anatoli N. Evtushenkov 《Journal of Phytopathology》2008,156(10):638-640
Erwinia amylovora is a phytopathogenic bacterium that causes fire blight, an economically important disease of Rosaceae . Several isolates from pears and apples with fire blight symptoms from Belarus were identified as E. amylovora . All tested isolates were yellow and mucoid on MM2Cu medium, positive in levan production and showed pathogenicity in immature pear fruits. These isolates have identical total protein patterns with E. amylovora 1/79. The PCR with specific primers for E. amylovora harpin gene also gave positive results. 相似文献
79.
Valcho D. Zheljazkov Ekaterina A. Jeliazkova Natasha Kovacheva Anatoli Dzhurmanski 《Environmental and Experimental Botany》2008,64(3):207-216
The hypothesis tested in this study was if medicinal plants could be grown as alternative crops in heavy metal polluted soils without contamination of the final marketable produce. Furthermore, medicinal crops may offer a phytoremediation option for mildly heavy metal polluted agricultural soils. The effect of metal-enriched soils was evaluated in five medicinal species (Bidens tripartita L., Leonurus cardiaca L., Marrubium vulgare L., Melissa officinalis L. and Origanum heracleoticum L.). Soils were sampled in the vicinities of the Non-Ferrous Metals Combine (Pb–Zn smelter) near Plovdiv, Bulgaria, from plots at 0.5 km (soil 1), 3 km (soil 2), 6 km (soil 3) and 9 km (control soil) from the smelter. Cadmium, Pb and Zn concentration in soil 1 were above the critical total (HNO3-extractable) concentrations for these elements in soils. Generally, heavy metals in soil 1 decreased dry mater yields of the five species relative to the control. However, the essential oil content of M. vulgare, M. officinalis and O. heracleoticum was within the usual range for respective species and was not affected by the treatments. The overall metal uptake was in the order: B. tripartita > M. vulgare > O. heracleoticum > L. cardiaca > M. officinalis for Cd, L. cardiaca = M. vulgare > B. tripartita = M. officinalis = O. heracleoticum for Pb, L. cardiaca = M. vulgare > O. heracleoticum > B. tripartita = M. officinalis for Cu and B. tripartita > L. cardiaca = M. vulgare > M. officinalis = O. heracleoticum for Mn and Zn. Overall, metal concentration in plant parts was in the order: roots > leaves > flowers > stems for Cd, Pb and Cu, leaves > roots > flowers > stems for Mn and Zn. The concentration of Cd, Pb, Cu and Zn in plant tissue correlated to the exchangeable (EXCH) and the carbonate (CARB) bound fractions of metals in soil. Heavy metals caused disruptions of the plasma membrane of some root cortical cells and alterations in chloroplasts thylakoids in plants grown in soil 1. Metal content in teas prepared from the species was negligible, the essential oils were free of metals. Generally, the transfer factor (TF) was less than 1, indicating the tested species did not have a significant phytoextraction potential. This study demonstrated the three essential oil species M. vulgare, M. officinalis and O. heracleoticum can be grown as alternative high-value crops in metal polluted agricultural soils around the smelter and provide metal-free marketable produce. 相似文献
80.
Stevens W Kamali A Karita E Anzala O Sanders EJ Jaoko W Kaleebu P Mulenga J Dally L Fast P Gilmour J Farah B Birungi J Hughes P Manigart O Stevens G Yates S Thomson H von Lieven A Krebs M Price MA Stoll-Johnson L Ketter N 《PloS one》2008,3(4):e2043