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91.
92.
Saurabh Sudha Dhiman Dayanand Kalyani Sujit Sadashiv Jagtap Jung-Rim Haw Yun Chan Kang Jung-Kul Lee 《Applied microbiology and biotechnology》2013,97(3):1081-1091
Enhanced catalytic activities of different lignocellulases were obtained from Armillaria gemina under statistically optimized parameters using a jar fermenter. This strain showed maximum xylanase, endoglucanase, cellobiohydrolase, and β-glucosidase activities of 1,270, 146, 34, and 15 U mL?1, respectively. Purified A. gemina xylanase (AgXyl) has the highest catalytic efficiency (k cat/K m?=?1,440 mg?mL?1?s?1) ever reported for any fungal xylanase, highlighting the significance of the current study. We covalently immobilized the crude xylanase preparation onto functionalized silicon oxide nanoparticles, achieving 117 % immobilization efficiency. Further immobilization caused a shift in the optimal pH and temperature, along with a fourfold improvement in the half-life of crude AgXyl. Immobilized AgXyl gave 37.8 % higher production of xylooligosaccharides compared to free enzyme. After 17 cycles, the immobilized enzyme retained 92 % of the original activity, demonstrating its potential for the synthesis of xylooligosaccharides in industrial applications. 相似文献
93.
Induction by ouabain of hemoglobin synthesis in cultured friend erythroleukemic cells 总被引:1,自引:0,他引:1
Induction of erythroid differentiation in ouabain-resistant murine erythroleukemia cells by ouabain is reported. Ouabain induction results in the appearance of hemoglobin-containing cells 12–24 hr earlier than induction of the same clone by dimethyl sulfoxide. The levels of globin mRNA after ouabain induction are similar in amount to the globin mRNA levels observed after induction by dimethyl sulfoxide. The concentration of ouabain required to induce hemoglobin synthesis depends upon the K+ ion levels in the culture medium. Lowering the extracellular K+ ion concentration 2–4 fold reduced by 10–40 fold the ouabain concentration necessary for the induction of hemoglobin synthesis. In low K+ medium (1.8 mM), ouabain is an effective inducer of hemoglobin synthesis at a concentration of 0.02 mM. This K+ effect is specific for ouabain induction, since induction by other inducers, such as dimethyl sulfoxide and dimethyl acetamide, does not exhibit this marked sensitivity to the levels of K+ ions in the culture medium. These results suggest that the binding of ouabain to the plasma membrane enzyme, ATPase, is required for the induction of erythroid differentiation by ouabain. A small but significant proportion of wild-type, ouabain-sensitive cells also can be induced by ouabain, below ouabain concentrations that are toxic to these cells. The observation that the binding of ouabain to the ATPase induces hemoglobin synthesis suggests that changes in the intracellular concentration of K+ ions may be involved in the control of erythroid differentiation in Friend erythroleukemic cells. 相似文献
94.
95.
Byung-Chul Choi Hang-Sik Shin Su-Yol Lee Tak Hur 《The International Journal of Life Cycle Assessment》2006,11(2):122-128
Background, Aims and Scope Telecommunication and information technology, dramatically emerged during the last decade, has generated environmental problems
by accelerating mass production, mass consumption, and mass disposal of personal computers (PCs) in Korea. In addition, it
has led the Korean new economy. The Korean government has encouraged researchers and industry to study the environmental impact,
adequate disposal treatment, and the reasonable recycling rate of an end-of-life personal computer. The main purpose of this
research is to investigate the life cycle environmental impact of PCs and to determine the desirable or feasible recycle rate
of an end-of-life PC. An LCA on a PC was performed based on different recycling scenario. Target audiences are new product
developers, designers, product recovery managers and environmental policy makers who are interested in the environmental impact
of PCs and recycling of end-of-life products.
Methods A target product is a Pentium IV personal computer made in Korea in 2001, excluding the monitor and peripheral equipment.
The procedure of the LCA followed the ISO14040 series. System boundary includes the entire life cycle of the product, including
pre-manufacturing (the electrical parts and components manufacturing), manufacturing, transportation, use, and disposal. The
LCI and impact assessment database for a PC was constructed using SIMAPRO version 4.0 software and LCI information was compiled
by site-specific data and the Korean national database. The LCA was performed on different recycling scenarios: one being
that of the current recycling rate of 46%, and the other being the ideal condition of a 100% recycling rate.
Results and Discussion Abiotic depletion, global warming, ecotoxicity, human toxicity, acidification, ozone layer depletion, photo-oxidant formation,
and eutrophication are adopted as the impact categories. The pre-manufacturing stage was a significant stage for all of the
environmental parameters, besides human toxicity potential. PC manufacturing consists of rather simple processes such as assembly
and packaging. For improving the environmental performance of PCs, environmental management approaches of design for the environment
and green procurement are recommended. The use stage had a significant potential due to the electricity consumption produced
by burning fossil fuel. The disposal stage's contribution to environmental impact was largest in human toxicity, and second
largest in ozone layer depletion potential. The PC recycling was shown to inhibit all environmental impacts with the exception
of the ozone depletion and ecotoxicity potential. The increase of light oil, nitric acid, sulfuric acid, and deoxidating agent
consumption during the recycling process contributes to the environmental impact of ozone and ecotoxicity parameters. Current
recovery and recycling technologies should be taken into account for enhancing the benefits of recycling. Anyway, the effectiveness
of recycling was highlighted by this study. PC recycling reduces the total environmental impact of the product. The PC recycling
is recommended to be raised up to at least 63% in order to reduce the environmental burdens of a PC in other life cycle stages.
Conclusion and Recommendation This study implies that design for the environment (DfE) in the product design stage and green procurement are recommended
for improving the entire environmental performance of electronic equipment such as PCs. The recycling of waste PCs clearly
reduces the environmental burden. There are, however, trade-offs among environmental parameters according to the PC recycling
rate. Current recycling methods are not effective in reducing ozone depletion and ecotoxicity environmental impact. The product
recovery is another key for efficient recycling. Efficient reverse logistics to collect and transport end-of-life PCs should
be taken into account to enhance recycling effects. There were several electrical parts not included in this assessment, due
to the unavailability of adequate data. Further studies with more detail and reliable inventories for electrical parts and
sub-components are recommended. Furthermore, costs of recycling should also be treated in further research. 相似文献
96.
Hyun Seok Kim Saurabh Mendiratta Jiyeon Kim Chad Victor Pecot Jill E. Larsen Iryna Zubovych Bo Yeun Seo Jimi Kim Banu Eskiocak Hannah Chung Elizabeth McMillan Sherry Wu Jef De Brabander Kakajan Komurov Jason E. Toombs Shuguang Wei Michael Peyton Noelle Williams Adi F. Gazdar Bruce A. Posner Rolf A. Brekken Anil K. Sood Ralph J. Deberardinis Michael G. Roth John D. Minna Michael A. White 《Cell》2013
97.
Yeast studies identified the evolutionarily conserved core ATG genes responsible for autophagosome formation. However, the SNARE-dependent machinery involved in autophagosome fusion with the vacuole in yeast is not conserved. We recently reported that the SNARE complex consisting of Syx17 (Syntaxin 17), ubisnap (SNAP-29) and Vamp7 is required for the fusion of autophagosomes with late endosomes and lysosomes in Drosophila. Syx17 mutant flies are viable but exhibit neuronal dysfunction, locomotion defects and premature death. These data point to the critical role of autophagosome clearance in organismal homeodynamics. 相似文献
98.
Mapping a locus controlling a quantitative genetic trait (e.g. blood pressure) to a specific genomic region is of considerable
contemporary interest. Data on the quantitative trait under consideration and several codominant genetic markers with known
genomic locations are collected from members of families and statistically analysed to estimate the recombination fraction,
θ, between the putative quantitative trait locus and a genetic marker. One of the major complications in estimating θ for
a quantitative trait in humans is the lack of haplotype information on members of families. We have devised a computationally
simple two-stage method of estimation of θ in the absence of haplotypic information using the expectation-maximization (EM)
algorithm. In the first stage, parameters of the quantitative trait locus (QTL) are estimated on the basis of data of a sample
of unrelated individuals and a Bayes’s rule is used to classify each parent into a QTL genotypic class. In the second stage,
we have proposed an EM algorithm for obtaining the maximum-likelihood estimate of θ based on data of informative families
(which are identified upon inferring parental QTL genotypes performed in the first stage). The purpose of this paper is to
investigate whether, instead of using genotypically ‘classified’ data of parents, the use of posterior probabilities of QT
genotypes of parents at the second stage yields better estimators. We show, using simulated data, that the proposed procedure
using posterior probabilities is statistically more efficient than our earlier classification procedure, although it is computationally
heavier. 相似文献
99.
Wani SA Ahmad F Zargar SA Dar ZA Dar PA Tak H Fomda BA 《The Journal of parasitology》2008,94(3):591-593
Soil-transmitted helminths (STHs) remain a major threat to the health of children throughout the world, mostly in developing nations. The aim of the present study was to determine any relationship between STHs and hemoglobin status in school children of Kashmir Valley (India). Stool and blood samples were collected from 382 male and female school children in the age group of 5-15 yr from all 6 school districts of the Kashmir Valley. Finger-prick blood samples were used to collect the hemoglobin, which was then measured on-site by Sahli's acid hematin method; stool samples were processed using both simple smear and zinc sulphate concentration methods. Of the 382 children surveyed, 299 (78.27%) were infected with Ascaris lumbricoides, Trichuris trichiura, or both. Children infected by STHs were found to have lower mean values of hemoglobin than uninfected children. The present study reveals that STHs are abundant among school children of Kashmir Valley, creating a negative effect on the hemoglobin values and indicating the necessity of implementing control measures. 相似文献
100.
Yaakov A. Levine Frieda A. Koopman Michael Faltys April Caravaca Alison Bendele Ralph Zitnik Margriet J. Vervoordeldonk Paul Peter Tak 《PloS one》2014,9(8)