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81.
Cytotechnology - Physical methods are widely utilized to deliver nucleic acids into cells such as electro-transfection or heat shock. An efficient gene electro-transfection requires the best... 相似文献
82.
M Azam M Kesarwani K Natarajan A Datta 《Biochemical and biophysical research communications》2001,289(4):807-812
The oxalate decarboxylase (OXDC) gene from Collybia velutipes is overexpressed as an active form in Schizosaccharomyces pombe. The recombinant enzyme shows similar pH optima and stability, while substrate kinetic analysis shows a ninefold decrease in K(m) value with respect to native OXDC. Most of the expressed protein was present in periplasm and remained firmly bound to cell-wall materials. However, 20% of enzyme expressed was secreted out into the medium suggesting the presence of a secretion signal (C. velutipes) in the oxalate decarboxylase gene. This secretion signal is associated with the N-terminal of OXDC as is evident by secretion of nonsecretory genes AmA1 and beta-galactosidase. An expression vector using this signal is constructed for expression and secretion of heterologous proteins in S. pombe. 相似文献
83.
84.
Insulin receptors from rat brain and liver were purified. Brain purified receptor exhibited protein bands of apparent Mr = 135,000 and 95,000 molecular weight corresponding to alpha- and beta-subunits, retained a tyrosine specific protein kinase activity and demonstrated phosphorylation that is hormonally sensitive. Antisera were raised against both insulin receptor preparations and enzyme-linked immunosorbent assay was developed. The comparison of two insulin receptors was based on a displacement enzyme-linked immunosorbent assay where antisera were interchanged on predetermined optimal dilutions. This indicated that both insulin receptors possess some unique antigenic determinants thereby implying a structural difference. 相似文献
85.
Summary A pot experiment was conducted to study the transformations of organic and inorganic N in soil and its availability to maize plants. Inorganic N was in the form of15N labelled ammonium sulphate (As) and15N labelledSesbania aculeata (Sa), a legume, was used as organic N source. Plants utilized 20% of the N applied as As; presence of Sa reduced the uptake to 14%. Only 5% of the Sa-N was taken up by the plants and As had no effect on the availability of N from Sa. Losses of N from As were found to be 40% which were reduced to 20% in presence of Sa. Losses of N were also observed from Sa which increased in the presence of As. Application of As had no effect on the availability of soil or Sa-N. However, more As-N was transported into microbial biomass and humus components in the presence of Sa.Plants derived almost equal amounts of N from different sourcesi.e., soil, Sa and As. However, more As-N was transported into the shoots whereas the major portion of nitrogen in the roots was derived from Sa. 相似文献
86.
[Carbonyl-14C] methabenzthiazuron (MBT) was applied to an arid region soil at a rate of 5mg kg−1 soil to give a14C content of 2400 KB kg−1 soil. After 15 weeks of incubation at 22°C and 50% of the maximum water holding capacity of the soil, 7.2% of the applied14C was mineralized to14CO2. Where the soil was amended with wheat straw, total mineralization increased to 17.3%. Soil disturbance caused a significant
increase while chloroform fumigation caused a significant decrease in the rate of14CO2 production, both from amended and unamended soils. These results suggest that MBT is degraded mainly through microbial co-metabolism.
Wheat straw amendment resulted in increased transformation of MBT into soil humus. In unamended soil, a major portion of14C was recovered in fulvic acid and in fractions extracted with organic solvents. Recovery of14C in non-extractable bound residues (humins) increased as incubation progressed and seemed to be derived from the fulvic acid
fraction, which showed a concomitant decrease.
More than 99% of the residual14C in unamended soil consisted of unaltered MBT; the remainder occurred as 1-methyl-1 (benzthiazolyl) urea. In amended soil,
a relatively higher percentage of the extractable14C was found in the metabolite. Small amounts of three unidentified14C-labelled compounds were also observed.
In amended soil, disturbance caused a decrease in extractable-14C whereas fumigation caused a significant increase, as compared to the untreated control. The effects were more pronounced
when the soils were reated at an early stage of incubation. In general, soil disturbance increased the availability of MBT
for further transformations while chloroform fumigation decreased the process. 相似文献
87.
Image analysis-based measurement of DNA supercoiling changes in transformed and nontransformed human cell lines 总被引:1,自引:0,他引:1
Yvonne C. Taylor Xiafang Zhang Azam J. Parsian Pamela G. Duncan 《Experimental cell research》1991,197(2):222-228
An image analysis system was used to visualize and measure the changes in nucleoid diameter (nuclear matrix core plus extruded DNA loops) which occur when increasing concentrations of propidium iodide are used to titrate the DNA supercoiling response. Parallel core size measurements allow estimates of the changes in apparent DNA loop size. Unlike sedimentation assays, DNA loop size estimates are not influenced by particle mass, require no prior cell labeling, and can be performed on a per cell basis. This technique was used to examine changes in DNA loop characteristics which may occur when cells are transformed or undergo changes in their proliferative state. SV40-transformation of human diploid fibroblast lines resulted in a significant increase in both the nucleoid core and average DNA loop size. Lymphoblast cell lines also had larger nucleoid dimensions than normal lymphocytes. The response of several established human tumor cell lines indicated slightly increased loop but not core sizes as compared to normal human diploid fibroblasts. Changes in proliferative state also resulted in changes in DNA loop characteristics as measured in this assay. Both quiescent fibroblasts and unstimulated lymphocytes appeared to have smaller or more condensed DNA loop structures than their proliferating counterparts. These results demonstrate the utility of this assay in detecting changes in DNA loop structure which occur in association with changes in the proliferative activity of cells in culture. 相似文献
88.
This study examined the effects of different gums viz. gum arabic (GA), guar gum (GG), k-carrageenan gum (KG), and xanthan gum (XG) on rheological and 3D printing characteristics of vitamin D (Vit D) enriched orange concentrate (OC) wheat starch (WS) blends. The textural and microstructural properties of printed objects from above mixture were evaluated and compared. The addition of gums induced an increase in apparent viscosity, storage modulus (G′), and loss modulus (G″) of the OC-WS mixtures, while GA decreased the apparent viscosity and G′. Nuclear magnetic resonance (NMR) analysis of 3D printed samples revealed that the movement of transverse time (T2) toward closer to 0 ms indicated an increase in immobilized and bound water populations suggesting the gel formation. The slight shift toward shorter wavelength in FT-IR results for the broadband centered around 3400 cm?1 after addition of gums possibly caused an increase of G′ and load bearing capacity of the blends. 3D printing characteristics revealed that the objects printed using KG containing blend possessed maximum fidelity to the target geometry and good loading bearing capacity, preventing collapsing over time due to the proper G′ value. At tanδ of 0.238, OC-WS-KG mixture achieved the best printing condition. Higher tanδ of GA (0.038) containing samples led to an unwanted collapse of the printed constructs. The objects printed using KG also exhibited the smoothest visible surface as well as microstructure and best mastication properties. Considering the studied features, vitamin D enriched OC with WS-KG was found to be the best match for orange fruit concentrate-based 3D food printing. This work demonstrates the novel ways to develop fortified 3D printed foods. 相似文献
89.
Different applications of virus‐like particles in biology and medicine: Vaccination and delivery systems 下载免费PDF全文
Virus‐like particles (VLPs) mimic the whole construct of virus particles devoid of viral genome as used in subunit vaccine design. VLPs can elicit efficient protective immunity as direct immunogens compared to soluble antigens co‐administered with adjuvants in several booster injections. Up to now, several prokaryotic and eukaryotic systems such as insect, yeast, plant, and E. coli were used to express recombinant proteins, especially for VLP production. Recent studies are also generating VLPs in plants using different transient expression vectors for edible vaccines. VLPs and viral particles have been applied for different functions such as gene therapy, vaccination, nanotechnology, and diagnostics. Herein, we describe VLP production in different systems as well as its applications in biology and medicine. © 2015 Wiley Periodicals, Inc. Biopolymers 105: 113–132, 2016. 相似文献
90.
Azam Yazdani Akram Yazdani Ahmad Saniei Eric Boerwinkle 《Metabolomics : Official journal of the Metabolomic Society》2016,12(6):104