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991.
Marina G. Pessôa Kele A.C. Vespermann Bruno N. Paulino Mayara C.S. Barcelos Glaucia M. Pastore Gustavo Molina 《Biotechnology advances》2019,37(2):319-339
Nowadays, food, cosmetic, environmental and pharmaceutical fields are searching for alternative processes to obtain their major products in a more sustainable way. This fact is related to the increasing demand from the consumer market for natural products to substitute synthetic additives. Industrial biotechnology appears as a promising area for this purpose; however, the success of its application is highly dependent of the availability of a suitable microorganism. To overcome this drawback, the isolation of microorganisms from diverse sources, including fermented food, adverse environments, contaminated samples or agro-industrial wastes is an important approach that can provide a more adaptable strain able to be used as biocatalyst and that exhibit resistance to industrial conditions and high yields/productivities in biotechnological production of natural compounds. The aim of this review is to provide a solid set of information on the state of the art of isolation and screening studies for obtaining novel biocatalysts able to produce natural compounds, focusing in aromas, biosurfactants, polysaccharides and microbial oils. 相似文献
992.
993.
Hong Yi Joshua D. Strauss Zunlong Ke Eric Alonas Rebecca S. Dillard Cheri M. Hampton Kristen M. Lamb Jason E. Hammonds Philip J. Santangelo Paul W. Spearman Elizabeth R. Wright 《The journal of histochemistry and cytochemistry》2015,63(10):780-792
Numerous methods have been developed for immunogold labeling of thick, cryo-preserved biological specimens. However, most of the methods are permutations of chemical fixation and sample sectioning, which select and isolate the immunolabeled region of interest. We describe a method for combining immunogold labeling with cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET) of the surface proteins of intact mammalian cells or the surface glycoproteins of assembling and budding viruses in the context of virus-infected mammalian cells cultured on EM grids. In this method, the cells were maintained in culture media at physiologically relevant temperatures while sequentially incubated with the primary and secondary antibodies. Subsequently, the immunogold-labeled specimens were vitrified and observed under cryo-conditions in the transmission electron microscope. Cryo-EM and cryo-ET examination of the immunogold-labeled cells revealed the association of immunogold particles with the target antigens. Additionally, the cellular structure was unaltered by pre-immunolabeling chemical fixation and retained well-preserved plasma membranes, cytoskeletal elements, and macromolecular complexes. We think this technique will be of interest to cell biologists for cryo-EM and conventional studies of native cells and pathogen-infected cells. 相似文献
994.
A blue CaMgSi2O6:Eu2+ phosphor was prepared by the solid‐state reaction method and the phosphor characterized in terms of crystal structure, particle size, photoluminescence (PL), thermoluminescence (TL) and mechanoluminescence (ML) properties using X‐ray diffraction (XRD), transmission electron microscopy (TEM), PL spectroscopy, TLD reader and ML impact technique. The XRD result shows that phosphor is formed in a single phase and has a monoclinic structure with the space group C2/c. Furthermore, the PL excitation spectra of Eu2+‐doped CaMgSi2O6 phosphor showed a strong band peak at 356 nm and the PL emission spectrum has a peak at 450 nm. The depths and frequency factors of trap centers were calculated using the TL glow curve by deconvolution method in which the trap depths were found to be 0.48 and 0.61 eV. The formation of CaMgSi2O6:Eu2+ phosphor was confirmed by Fourier transform infrared spectroscopy. The ML intensity increased linearly with the impact velocity of the piston used to deform the phosphor. It was shown that the local piezoelectricity‐induced electron bombardment model is responsible for the ML emission. Finally, the optical properties of CaMgSi2O6:Eu2+ phosphors are discussed. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
995.
In Situ TEM Observation of Electrochemical Lithiation of Sulfur Confined within Inner Cylindrical Pores of Carbon Nanotubes 下载免费PDF全文
Hyea Kim Jung Tae Lee Alexandre Magasinski Kejie Zhao Yang Liu Gleb Yushin 《Liver Transplantation》2015,5(24)
Lithium insertion into sulfur confined within 200 nm cylindrical inner pores of individual carbon nanotubes (CNTs) was monitored in situ in a transmission electron microscope (TEM). This electrochemical reaction was initiated at one end of the S‐filled CNTs. The material expansion during lithiation was accommodated by the expansion into the remaining empty pore volume and no fracture of the CNT walls was detected. A sharp interface between the initial and lithiated S was observed. The reaction front was flat, oriented perpendicular to the confined S cylinder, and propagated along the cylinder length. Lithiation of S in the proximity of conductive carbon proceeded at the same rate as the one in the center of the pore, suggesting the presence of electron pathways at the Li2S/S interface. Density of states calculations further confirmed this hypothesis. In situ electron diffraction showed a direct phase transformation of S into nanocrystalline Li2S without detectable formation of any intermediates, such as polysulfides and LiS. These important insights may elucidate some of the reaction mechanisms and guide the improvements in the design of C–S nanocomposites for high specific energy Li–S batteries. The proposed use of conductive CNTs with tunable pore diameter as cylindrical reaction vessels for in situ TEM studies of electrochemical reactions proved to be highly advantageous and may help to resolve the ongoing problems in battery technology. 相似文献
996.
Towards automated screening of two-dimensional crystals 总被引:1,自引:0,他引:1
Cheng A Leung A Fellmann D Quispe J Suloway C Pulokas J Abeyrathne PD Lam JS Carragher B Potter CS 《Journal of structural biology》2007,160(3):324-331
Screening trials to determine the presence of two-dimensional (2D) protein crystals suitable for three-dimensional structure determination using electron crystallography is a very labor-intensive process. Methods compatible with fully automated screening have been developed for the process of crystal production by dialysis and for producing negatively stained grids of the resulting trials. Further automation via robotic handling of the EM grids, and semi-automated transmission electron microscopic imaging and evaluation of the trial grids is also possible. We, and others, have developed working prototypes for several of these tools and tested and evaluated them in a simple screen of 24 crystallization conditions. While further development of these tools is certainly required for a turn-key system, the goal of fully automated screening appears to be within reach. 相似文献
997.
Ståhl PL Gantelius J Natanaelsson C Ahmadian A Andersson-Svahn H Lundeberg J 《Genomics》2007,90(6):741-745
In this paper we describe a method that uses the nearly covalent strength biotin-streptavidin interaction to attach a paramagnetic bead of micrometer size to a DNA molecule of nanometer size, scaling up the spatial size of a query DNA strand by a factor of 1000, making it visible to the human eye. The use of magnetic principles enables rapid binding and washing of detector beads, facilitating a readout of amplified DNA sequences in a few minutes. Here we exemplify the method on mitochondrial DNA variations using an array platform. Visual identification and documentation can be performed with an ordinary mobile phone equipped with a built-in camera. 相似文献
998.
The performance of synchronous parallel polynomial root extraction on a ring multicomputer 总被引:1,自引:0,他引:1
Hamid Sarbazi-Azad 《Cluster computing》2007,10(2):167-174
In this paper, a parallel algorithm for computing the roots of a given polynomial of degree n on a ring of processors is proposed.
The algorithm implements Durand–Kerner’s method and consists of two phases: initialisation, and iteration. In the initialisation
phase all the necessary preparation steps are realised to start the parallel computation. It includes register initialisation
and initial approximation of roots requiring 3n−2 communications, 2 exponentiation, one multiplications, 6 divisions, and 4n−3 additions. In the iteration phase, these initial approximated roots are corrected repeatedly and converge to their accurate
values. The iteration phase is composed of some iteration steps, each consisting of 3n communications, 4n+3 additions, 3n+1 multiplications, and one division.
相似文献
Hamid Sarbazi-AzadEmail: Email: |
999.
Scott N. Johnson John W. Crawford Peter J. Gregory Dmitry V. Grinev Richard W. Mankin Gregory J. Masters Philip J. Murray Diana H. Wall Xiaoxian Zhang 《Agricultural and Forest Entomology》2007,9(1):39-46
1 Root‐feeding insects are now considered to play a greater role in ecosystem processes than previously thought, yet little is known about their specific interactions with host plants compared with above‐ground insect herbivores. Methodological difficulties associated with studying these insects in the soil, together with the lack of empirical and theoretical frameworks, have conventionally hindered progress in this area. 2 This paper reviews recent empirical and theoretical developments that have been adopted for studying root‐feeding insects, focusing on the non‐invasive techniques of X‐ray tomography and acoustic field detection and how these can be integrated with new mathematical modelling approaches. 3 X‐ray tomography has been used for studying the movements of several insects within the soil and has helped to characterize the host plant location behaviour of the clover root weevil, Sitona lepidus. Acoustic detection of soil insects has been used in various managed systems, ranging from nursery containers to citrus groves. 4 Mathematical modelling plays a complementary role for investigating root‐feeding insects, illustrated by a number of published models. A model is presented for the movement of S. lepidus in the soil, which suggests that these insects undergo Lévy movements, similar to those recently demonstrated for above‐ground organisms. 5 The future directions and challenges for investigating root‐feeding insects are discussed in the context of the wider ecosystem, incorporating both above and below‐ground organisms. 相似文献
1000.
It is of particular intrigue to synthesize, analyze anti-bacterial, anti-inflammatory activity, cytotoxicity effect of clove and cardamom reinforced zirconium oxide nanoparticles to coat the orthodontic archwires and study its ramifications. Characterization of nanoparticles was done using Transmission electron microscopic analysis (TEM). Antimicrobial activity was assessed using agar well diffusion method. Cytotoxic effect was assessed using Brine Shrimp Assay. Anti-inflammatory activity was completed using Bovine Serum Albumin (BSA). A Digital magnetic stirrer with a hot plate was used to coat orthodontic arch wires such as NiTi and SS. TEM spherical shape was of size 5 -20 nm. Minimal cytotoxicity was observed at 50 µL. Anti-inflammatory property was fair. Antimicrobial activity against Lactobacillus species, streptococcus mutans staphylococcus aureus and Candida albicans was recorded. NiTi and SS showed a colour shift from silver to orange red with a uniform surface coating on wires. Thus, green synthesized zirconium oxide nanoparticles have potent antimicrobial, anti-inflammatory properties with minimal cytotoxicity for further consideration as nano-coatings on orthodontic archwires such as NiTi and Stainless Steel. 相似文献