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61.
Aulus EAD Barbosa Érika VS Albuquerque Maria CM Silva Djair SL Souza Osmundo B Oliveira-Neto Arnubio Valencia Thales L Rocha Maria F Grossi-de-Sa 《BMC biotechnology》2010,10(1):44
Background
Coffee is an important crop and is crucial to the economy of many developing countries, generating around US70 billion per year. There are 115 species in the < i > Coffea < /i > genus, but only two, < i > C. arabica < /i > and < i > C. canephora < /i > , are commercially cultivated. Coffee plants are attacked by many pathogens and insect-pests, which affect not only the production of coffee but also its grain quality, reducing the commercial value of the product. The main insect-pest, the coffee berry borer ( < i > Hypotheneumus hampei < /i > ), is responsible for worldwide annual losses of around US70 billion per year. There are 115 species in the Coffea genus, but only two, C. arabica and C. canephora, are commercially cultivated. Coffee plants are attacked by many pathogens and insect-pests, which affect not only the production of coffee but also its grain quality, reducing the commercial value of the product. The main insect-pest, the coffee berry borer (Hypotheneumus hampei), is responsible for worldwide annual losses of around US500 million. The coffee berry borer exclusively damages the coffee berries, and it is mainly controlled by organochlorine insecticides that are both toxic and carcinogenic. Unfortunately, natural resistance in the genus Coffea to H. hampei has not been documented. To overcome these problems, biotechnological strategies can be used to introduce an α-amylase inhibitor gene (α-AI1), which confers resistance against the coffee berry borer insect-pest, into C. arabica plants. 相似文献62.
63.
CM Galmarini A Kertesz R Oliva J Porta F C Galmarini 《Cancer immunology, immunotherapy : CII》1998,15(4):282-285
Bone metastasis in the hand is rare. The etiology is quite different from that of metastasis to other bones; bronchogenic
carcinoma is by far the most frequent case. Distal phalanges are mainly involved with irregular osteolysis and cortical destruction.
Differential diagnosis of phalangeal metastasis includes osteomyelitis, rheumatoid arthritis and gout. The prognosis is always
that of metastatic bronchial cancer with an average survival of three months. Treatment may involve distal digital amputation
or antalgic radiotherapy. A case of bronchogenic carcinoma with metastasis to the thumb is presented. The metastasis was located
in the distal phalanx of the left thumb. The primary tumor was located in the lung. Treatment consisted of amputation. The
overall survival was five months. 相似文献
64.
Microsatellite variation in Drosophila melanogaster and Drosophila simulans: a reciprocal test of the ascertainment bias hypothesis 总被引:2,自引:1,他引:1
Interspecific comparisons of microsatellite loci have repeatedly shown that
the loci are longer and more variable in the species from which they are
derived (the focal species) than are homologous loci in other (nonfocal)
species. There is debate as to whether this is due to directional evolution
or to an ascertainment bias during the cloning and locus selection
processes. This study tests these hypotheses by performing a reciprocal
study. Eighteen perfect dinucleotide microsatellite loci identified from a
Drosophila simulans library screen and 18 previously identified in an
identical Drosophila melanogaster library screen were used to survey
natural populations of each species. No difference between focal and
nonfocal species was observed for mean PCR fragment length. However,
heterozygosity and number of alleles were significantly higher in the focal
species than in the nonfocal species. The most common allele in the
Zimbabwe population of both species was sequenced for 31 of the 36 loci.
The length of the longest stretch of perfect repeat units is, on average,
longer in the focal species than in the non-focal species. There is a
positive correlation between the length of the longest stretch of perfect
repeats and heterozygosity. The difference in heterozygosity can thus be
explained by a reduction in the length of the longest stretch of perfect
repeats in the nonfocal species. Furthermore, flanking-sequence length
difference was noted between the two species at 58% of the loci sequenced.
These data do not support the predictions of the directional-evolution
hypothesis; however, consistent with the ascertainment bias hypothesis, the
lower variability in nonfocal species is an artifact of the microsatellite
cloning and isolation process. Our results also suggest that the magnitude
of ascertainment bias for repeat unit length is a function of the
microsatellite size distribution in the genomes of different species.
相似文献
65.
Prospects for estimating nucleotide divergence with RAPDs 总被引:11,自引:0,他引:11
The technique of random amplification of polymorphic DNA (RAPD), which is
simply polymerase chain reaction (PCR) amplification of genomic DNA by a
single short oligonucleotide primer, produces complex patterns of anonymous
polymorphic DNA fragments. The information provided by these banding
patterns has proved to be of great utility for mapping and for verification
of identity of bacterial strains. Here we consider whether the degree of
similarity of the banding patterns can be used to estimate nucleotide
diversity and nucleotide divergence. With haploid data, fragments generated
by RAPD-PCR can be treated in a fashion very similar to that for
restriction-fragment data. Amplification of diploid samples, on the other
hand, requires consideration of the fact that presence of a band is
dominant to absence of the band. After describing a method for estimating
nucleotide divergence on the basis of diploid samples, we summarize the
restrictions and criteria that must be met when RAPD data are used for
estimating population genetic parameters.
相似文献
66.
Guang-Hui Gou Liu Liu Sardorbek Abdubakiev Xue-Lei Xin Haji Akber Aisa Jun Li 《化学与生物多样性》2023,20(1):e202200904
Piper longum is a well-known spice and traditional medicine. It was revealed to possess anti-diabetic activity, but few information about its active component and underlying mechanism could be available. In this study, retrofractamides A ( 1 ) and C ( 2 ) isolated from P. longum showed potent inhibitory activity against PTP1B. Therefore, the potential mechanism was predicted by network pharmacology and molecular docking. PI3K/AKT was obtained as the most remarkable pathway against type 2 diabetes mellitus (T2DM), and AKT1 and GSK3β were yielded as the top two core targets of retrofractamides A ( 1 ) and C ( 2 ). Molecular docking of compounds with AKT1 and GSK3β showed strong binding affinity between them. Additionally, cellular experiments with a L6 cell model was conducted to further verify the above predictions. Results indicated that retrofractamides A ( 1 ) and C ( 2 ) exerted anti-diabetic effect via activating PI3K/AKT pathway, and they promoted glucose consumption, glucose uptake, glycogen synthesis and glycolysis. 相似文献
67.
68.
69.
R Simões WB Feitosa CM Mendes AC Nicacio FRO de Barros 《Biotechnic & histochemistry》2013,88(3):79-83
Sperm chromatin integrity is essential for accurate transmission of male genetic information, and normal sperm chromatin structure is important for fertilization. Protamine is a nuclear protein that plays a key role in sperm DNA integrity, because it is responsible for sperm DNA stability and packing until the paternal genome is delivered into the oocyte during fertilization. Our aim was to investigate protamine deficiency in sperm cells of Bos indicus bulls (Nelore) using chromomycin A3 (CMA3) staining. Frozen semen from 14 bulls were thawed, then fixed in Carnoy's solution. Smears were prepared and analyzed by microscopy. As a positive control of CMA3 staining, sperm from one bull was subjected to deprotamination of nuclei. The percentage of CMA3-positive bovine sperm did not vary among batches. Only two bulls showed a higher percentage of CMA3-positive sperm cells compared to the others. CMA3 is a simple and useful tool for detecting sperm protamine deficiency in bulls. 相似文献
70.
G B Principato V Bocchini G Rosi M C Aisa E Giovannini 《Comparative biochemistry and physiology. B, Comparative biochemistry》1984,78(2):485-491
Alkaline phosphatases (APs) present in Spirographis spallanzanii were extracted by water homogenization of butanol treatment. The enzymes solubilized as above were purified by acetone fractionation and then by DEAE-cellulose and Sephadex G-200 chromatography; separation of four AP forms was achieved, which were characterized by studying their molecular and catalytic properties. The various APs differ in molecular weight, electrophoretic mobility, optimum pH, but show similar Km values and substrate inhibition pattern. Kinetic studies carried out with several inhibitors show, in particular, the existence in these APs of a second binding site and suggest a possible role for them in the metabolism of phosphoric esters of the sugars. 相似文献