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91.
Th. Svend Andersen 《Grana》2013,52(1):5-13
A considerable variation in the size of modern Corylus avellana pollen mounted in silicone oil was noticed. It turned out that a residue of the silicone oil solvent (benzene) prevents shrinkage of the pollen grains, and that size-variations may be due to more or less incomplete evaporation of the solvent. Evaporation at 50[ddot]C is more effective than evaporation at room temperature. Diffusion of solvents from a plastic spatula and from the slide-sealing material may cause a swelling of the pollen. The size of pollen grains compressed by the cover slip may increase slightly due to deformation. Size changes with storage up to 17 years are random, compressed grains do not swell, and the average changes are insignificant. The size of Corylus pollen from various modern collections is compared. 相似文献
92.
Andersen SO 《Insect biochemistry and molecular biology》2011,41(8):620-627
Fifty years ago it was concluded that the highly elastic cuticular protein, resilin, is devoid of secondary structure and that the peptide chains are randomly coiled and easily and reversibly deformed. These properties indicate that resilin is an intrinsically disordered protein and suggest that also other cuticular proteins may contain disordered regions. Amino acid sequences are now available for cuticular proteins from many insect species, and several programs have been developed to predict the probability for a given protein to contain disordered regions.The present paper describes the results obtained when the predictors are applied to various types of cuticular proteins from several insects. The results suggest that most cuticular proteins contain shorter or longer disordered regions, and the possible functions for such regions are briefly discussed. 相似文献
93.
Christian Thomsen Henrik Klitgaard Malcolm Sheardown† Helen C. Jackson Karen Eskesen† Palle Jacobsen‡ Svend Treppendahl§ Peter D. Suzdak 《Journal of neurochemistry》1994,62(6):2492-2495
Abstract: The in vivo anticonvulsant effects and in vitro metabo-tropic glutamate receptor selectivity of ( S )-4-carboxy-3-hydroxy-phenylglycine [(S)-4C3HPG] were examined. Intracerebroventricular injection of (S)-4C3HPG dose-dependently antagonized audiogenic-induced clonic and tonic convulsions in DBA/2 mice with ED60 values of 76 and 110-nmol per mouse, respectively. (S)-4C3HPG dose-dependently inhibited the spontaneously evoked epileptic spikes in a cingulate cortex-corpus callosum slice preparation. (SJ-4C3HPG displaced the binding of [3 H]glutamate in membranes prepared from baby hamster kidney (BHK) cells expressing the metabotropic glutamate receptor mGluR1a with an EC50 of 5 β 1 u M. ( S )-4C3HPG dose-dependently antagonized glutamate-stimulated phosphoinositide hydrolysis in BHK cells expressing mGluR 1a with an IC50 of 15 β 3 μ M. ( S )-4C3HPG was, however, an agonist at mGluR2 with an EC60 of 21 β 4 μ M for inhibition of forskolin-stimulated cyclic AMP formation in BHK cells expressing the mGluR2. ( S )-4C3HPG had no effects at mGluR4a. These data suggest that the anticonvulsant action of ( S )-4C3HPG is mediated by combined antagonism of mGluRIa and agonism of mGluR2. These results suggest the importance of mGluR1a and/or mGluR2 in the control of epileptic activity. 相似文献
94.
Multivariate Analysis of Phenol in Freeze-Dried and Spray-Dried Insulin Formulations by NIR and FTIR
Maltesen MJ Bjerregaard S Hovgaard L Havelund S van de Weert M Grohganz H 《AAPS PharmSciTech》2011,12(2):627-636
Dehydration is a commonly used method to stabilise protein formulations. Upon dehydration, there is a significant risk the
composition of the formulation will change especially if the protein formulation contains volatile compounds. Phenol is often
used as excipient in insulin formulations, stabilising the insulin hexamer by changing the secondary structure. We have previously
shown that it is possible to maintain this structural change after drying. The aim of this study was to evaluate the residual
phenol content in spray-dried and freeze-dried insulin formulations by Fourier transform infrared (FTIR) spectroscopy and
near infrared (NIR) spectroscopy using multivariate data analysis. A principal component analysis (PCA) and partial least
squares (PLS) projections were used to analyse spectral data. After drying, there was a difference between the two drying
methods in the phenol/insulin ratio and the water content of the dried samples. The spray-dried samples contained more water
and less phenol compared with the freeze-dried samples. For the FTIR spectra, the best model used one PLS component to describe
the phenol/insulin ratio in the powders, and was based on the second derivative pre-treated spectra in the 850–650 cm−1 region. The best PLS model based on the NIR spectra utilised three PLS components to describe the phenol/insulin ratio and
was based on the standard normal variate transformed spectra in the 6,200–5,800 cm−1 region. The root mean square error of cross validation was 0.69% and 0.60% (w/w) for the models based on the FTIR and NIR spectra, respectively. In general, both methods were suitable for phenol quantification
in dried phenol/insulin samples. 相似文献
95.
Background
Cardiovascular disease (CVD) is highly prevalent in patients with chronic kidney disease (CKD). Inhibition of the renin-angiotensinsystem (RAS) in hypertension causes differential effects on central and brachial blood pressure (BP), which has been translated into improved outcome. The objective was to examine if a more complete inhibition of RAS by combining an angiotensin converting enzyme inhibitor (ACEI) and an angiotensin receptor antagonist (ARB) compared to monotherapy has an additive effect on central BP and pulse-wave velocity (PWV), which are known markers of CVD.Methods
Sixty-seven CKD patients (mean GFR 30, range 13–59 ml/min/1.73 m2) participated in an open randomized study of 16 weeks of monotherapy with either enalapril or candesartan followed by 8 weeks of dual blockade aiming at a total dose of 16 mg candesartan and 20 mg enalapril o.d. Pulse-wave measurements were performed at week 0, 8, 16 and 24 by the SphygmoCor device.Results
Significant additive BP independent reductions were found after dual blockade in aortic PWV (−0.3 m/s, P<0.05) and in augmentation index (−2%, P<0.01) compared to monotherapy. Furthermore pulse pressure amplification was improved (P<0.05) and central systolic BP reduced (−6 mmHg, P<0.01).Conclusions
Dual blockade of the RAS resulted in an additive BP independent reduction in pulse-wave reflection and arterial stiffness compared to monotherapy in CKD patients.Trial Registration
Clinical trial.gov NCT00235287http://www.clinicaltrials.gov/ct2/show/NCT00235287?term=ras+block&rank=1 相似文献96.
97.
Haaning S Radutoiu S Hoffmann SV Dittmer J Giehm L Otzen DE Stougaard J 《The Journal of biological chemistry》2008,283(45):31142-31152
Intrinsic structural disorder is a prevalent feature of proteins with chaperone activity. Using a complementary set of techniques, we have structurally characterized LjIDP1 (intrinsically disordered protein 1) from the model legume Lotus japonicus, and our results provide the first structural characterization of a member of the Lea5 protein family (PF03242). Contrary to in silico predictions, we show that LjIDP1 is intrinsically disordered and probably exists as an ensemble of conformations with limited residual beta-sheet, turn/loop, and polyproline II secondary structure. Furthermore, we show that LjIDP1 has an inherent propensity to undergo a large conformational shift, adopting a largely alpha-helical structure when it is dehydrated and in the presence of different detergents and alcohols. This is consistent with an overrepresentation of order-promoting residues in LjIDP1 compared with the average of intrinsically disordered proteins. In line with functioning as a chaperone, we show that LjIDP1 effectively prevents inactivation of two model enzymes under conditions that promote protein misfolding and aggregation. The LjIdp1 gene is expressed in all L. japonicus tissues tested. A higher expression level was found in the root tip proximal zone, in roots inoculated with compatible endosymbiotic M. loti, and in functional nitrogen-fixing root nodules. We suggest that the ability of LjIDP1 to prevent protein misfolding and aggregation may play a significant role in tissues, such as symbiotic root nodules, which are characterized by high metabolic activity. 相似文献
98.
Microcolony Cultivation on a Soil Substrate Membrane System Selects for Previously Uncultured Soil Bacteria 总被引:10,自引:4,他引:6
Traditional microbiological methods of cultivation recover less than 1% of the total bacterial species, and the culturable portion of bacteria is not representative of the total phylogenetic diversity. Classical cultivation strategies are now known to supply excessive nutrients to a system and therefore select for fast-growing bacteria that are capable of colony or biofilm formation. New approaches to the cultivation of bacteria which rely on growth in dilute nutrient media or simulated environments are beginning to address this problem of selection. Here we describe a novel microcultivation method for soil bacteria that mimics natural conditions. Our soil slurry membrane system combines a polycarbonate membrane as a growth support and soil extract as the substrate. The result is abundant growth of uncharacterized bacteria as microcolonies. By combining microcultivation with fluorescent in situ hybridization, previously “unculturable” organisms belonging to cultivated and noncultivated divisions, including candidate division TM7, can be identified by fluorescence microscopy. Successful growth of soil bacteria as microcolonies confirmed that the missing culturable majority may have a growth strategy that is not observed when traditional cultivation indicators are used. 相似文献
99.
Most bacteria are recalcitrant to traditional cultivation in the laboratory. The soil substrate membrane system provides a simulated environment for the cultivation of previously undescribed soil bacteria as microcolonies. The system uses a polycarbonate membrane as a solid support for growth and soil extract as the substrate. Diverse microcolonies can be visualized using total bacterial staining combined with fluorescence in situ hybridization (FISH) after 7-10-d incubation. Molecular typing shows that the majority of microcolony-forming bacteria recovered using this protocol were resistant to growth using standard methods. The protocol takes <4 h of bench time over the 10-d period. 相似文献
100.