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61.
Brad?PageEmail author Andrew?Welling Magaly?Chambellant Simon?D.?Goldsworthy Tony?Dorr Rick?van?Veen 《Polar Biology》2003,26(4):219-224
Fur seals were eliminated by sealers at Heard Island soon after its discovery in the 1850s. The first recorded breeding of Antarctic fur seals (Arctocephalus gazella) since sealing was reported in early 1963 (two pups). The most recent survey of the Heard Island fur-seal population was undertaken between November 2000 and March 2001, when 1,012 Antarctic fur-seal pups were born. This represents a fourfold increase since the last complete census in 1987/1988 (13 years), when 248 births were recorded. Pup estimates and counts available for eight breeding seasons since 1962/1963 suggest the population has been increasing at between 12 and 20% per year. Based on pup production, the breeding population is estimated to number approximately 4,100 seals. The number of fur seals on Heard Island peaked in late February/early March at 29,256 indicating that, in addition to the breeding population, a significant number of seals born elsewhere haul out on the island. Most of these are moulting sub-adult and adult males. As in 1987/1988, only one subantarctic fur-seal pup (A. tropicalis) was observed, suggesting this species is not colonising the island, as has been speculated. 相似文献
62.
Yu RZ Su JQ Grundy JS Geary RS Sewell KL Dorr A Levin AA 《Antisense & nucleic acid drug development》2003,13(1):57-66
ISIS 2302, an antisense phosphorothioate oligonucleotide (ODN) targeting human intercellular adhesion molecule-1 (ICAM-1) mRNA, is currently being evaluated for treatment of patients with Crohn's disease. From data collected in phase II clinical studies with ISIS 2302, validated population pharmacokinetic and exposure-response models were developed and used to simulate the plasma exposure and clinical response results for a proposed phase III trial design involving 100 patients treated with active drug and 50 patients treated with placebo. Simulated results of 1000 replications of the trial were calculated for various proposed dosing regimens. Overall, the simulated results indicated that a fixed dose regimen (250-400 mg, depending on patient sex and total body weight) given three times weekly provides both desirable ISIS 2302 plasma exposure and a high rate of clinical response in this patient population. However, the simulated results also suggest that inclusion of a larger number of patients than projected may be necessary to provide a desirable probability of study success (i.e., >80%), regarding demonstration of statistically significant differences between the active treatment and placebo groups for the primary clinical response measure (CCR rate). 相似文献
63.
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65.
Amoresano A; Andolfo A; Siciliano RA; Mele A; Coscarella A; De Santis R; Mauro S; Pucci P; Marino G 《Glycobiology》1998,8(8):779-790
MEN 11300 is a hybrid glycoprotein of 297 amino acids obtained by fusion of
the cDNA encoding GM-CSF with the cDNA encoding EPO followed by
transfection of the hybrid gene into CHO cells. The oligonucleotide
construct incorporated a spacing sequence between the two individual cDNAs
which encodes eight amino acids constituting a linker peptide intended to
separate the GM-CSF and EPO moieties. The recombinant MEN 11300 protein was
submitted to a detailed structural characterization including the
verification of the entire amino acid sequence, the assignment of the
disulfide bridges pattern, the identification of the glycosylation sites
and the definition of the glycosidic moiety, including site-specificity.
Partial processing of the C-terminal Arg residue and the occurrence of
N-glycosylation sites at Asn27, Asn155, Asn169, Asn214 were established.
Moreover, O-glycosylation at Ser257 and at the N-terminal region was also
detected. A large heterogeneity was observed in the N-glycans due to the
presence of differently sialylated and fucosylated branched complex type
oligosaccharides whereas O-linked glycans were constituted by GalGalNAc
chains with a different number of sialic acids. The disulfide bridges
pattern was established by direct FABMS analysis of the proteolytic digests
or by ESMS analysis of HPLC purified fractions. Pairing of the eight
cysteine residues resulted in Cys54-Cys96, Cys88-Cys121, Cys138-Cys292, and
Cys160-Cys164. This S-S bridges pattern is identical to that occurring in
the individual natural GM-CSF and EPO, thus showing that the two protein
moieties in MEN 11300 can independently acquire their native
three-dimensional structure.
相似文献
66.
Laurence J. Dorr 《Brittonia》1993,45(1):32-33
Hitherto “suppressed,”Cacao guianensis, based on a mixture of elements that can be referred to three currently recognized species (i.e.,Theobroma cacao, T. subincanum, andT. velutinum), is lectotypified by Aublet's illustrations of its flowers. This makesC. guianensis a taxonomic synonym ofT. cacao and encourages nomenclatural stability by permitting the continued use ofT. subincanum andT. velutinum. 相似文献
67.
Unusual pattern of bacterial ice nucleation gene evolution 总被引:5,自引:0,他引:5
Edwards AR; Van den Bussche RA; Wichman HA; Orser CS 《Molecular biology and evolution》1994,11(6):911-920
Bacterial ice nucleation activity (INA+ phenotype) can be traced to the
product of a single gene, ina. A remarkably sparse distribution of this
phenotype within three bacterial genera indicates that the ina gene may
have followed an unusual evolutionary path. Southern blot analyses, coupled
with assays for ice-nucleating ability, revealed that within four bacterial
species an ina gene is present in some strains but absent from others.
Results of hybridization experiments using DNA fragments that flank the ina
gene suggested that the genotypic dimorphism of ina may be anomalous. A
phylogenetic analysis of 16S ribosomal RNA gene sequences from a total of
14 ina+ and ina- bacterial strains indicated that the ina+ bacteria are not
monophyletic but instead phylogenetically interspersed among ina- bacteria.
The relationships of ina+ bacteria inferred from ina sequence did not
coincide with those inferred from the 16S data. These results suggest the
possibility of horizontal transfer in the evolution of bacterial ina genes.
相似文献
68.
Mukti H. Sarma Roswitha G. Dorr Ramaswamy H. Sarma 《Biochemical and biophysical research communications》1982,106(2):663-670
A modified polyacrylamide gel electrophoresis technique is used to separate the polypeptides after digestion of RNA polymerase with various concentration of trypsin. The subunits β and β′ and two large breakdown products of molecular weight of 147,000 and 141,000 are distinctly separated. At a very low level of trypsin σ and α are not cleaved while two major breakdown products of molecular weights of 110,000 and 43,000 appear from the larger subunits. At a still higher level of trypsin σ is converted to a polypeptide of molecular weight of 86,000 and other small fragments. DNA protects, to some extent, the σ and this polypeptide and also β and the two large breakdown products from trypsin digestion. It is also observed that rifamycin, an inhibitor of RNA synthesis, enhances the tryptic digestion of σ, only in the absence of MgCl2. 相似文献
69.
Membrane water permeability is habitually calculated from volume changes in Xenopus laevis oocytes during external osmotic challenges. Nevertheless, this approach is limited by the uncertainty on the oocyte internal composition. To circumvent this limitation a new experimental set up is introduced where the cell membrane of an emptied-out oocyte was mounted as a diaphragm between two chambers. In its final configuration the oocyte membrane was part of a closed compartment and net water movements induced swelling or shrinking of it. Volume changes were followed by video-microscopy and digitally recorded. In this manner, water movements could be continuously monitored while controlling chemical composition and hydrostatic pressure on both sides of the membrane. Using this novel experimental approach an increasing hydrostatic pressure gradient was applied to both mature (stage VI) and immature (stage IV) oocytes. The relative maximal volume change tolerated before disruption was similar in both cases (1.26+/-0.07 and 1.27+/-0.03 respectively) and similar to those previously reported under maximal osmotic stress. Nevertheless the osmotic permeability coefficient (P(OSM)) in mature oocytes ((1.72+/-0.58) x 10(-3) cm s(-1); n=6) was significantly lower than in immature oocytes ((5.18+/-0.59) x 10(-3) cm s(-1), n=5; p<0.005). 相似文献
70.
Lambert JD Sang S Dougherty A Caldwell CG Meyers RO Dorr RT Timmermann BN 《Phytochemistry》2005,66(7):811-815
Six lignans, including the cyclolignan 3,4'-dihydroxy-3',4'-dimethoxy-6,7'-cyclolignan, were isolated from the flowering tops of Larrea tridentata. Additionally the flavanone, (S)-4',5-dihydroxy-7-methoxyflavanone, was isolated for the first time from L. tridentata or any member of the family Zygophyllaceae. All of the compounds were assessed for their growth inhibitory activity against human breast cancer, human colon cancer and human melanoma cell lines. The lignans had IC50 values of 5-60 microM with the linear butane-type lignans being the most potent, and it was found that colon cancer cells were the least sensitive cell type tested. The relative potency of linear butane type lignans against human breast cancer appears to correlate positively with the number of O-methyl groups present on the molecule. 相似文献