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551.
F. G. Sulman D. Levy Y. Pfeifer E. Superstine E. Tal 《International journal of biometeorology》1975,19(3):202-209
Changes from normal weather to hot dry heat (Sharav) or cold rainy weather (Bora) evoked specific reactions of neurohormone secretion in 500 female weather-sensitive patients studied in Jerusalem (Israel). Urinary 17-KS increased only during the weather front period, whereas 17-OH increased steadily during the weather front and heat period. Adrenaline and noradrenaline decreased during both the weather front and the following heat period, clinically presenting all symptoms of adrenal medulla exhaustion. Serotonin increased during the weather front period and returned to normal thereafter, whether it was followed by a hot spell or a cold period, whereas 5-HIAA was increased throughout the weather front and hot period. Clinically, serotonin overproduction manifested itself as the serotonin irritation syndrome (migraine, etc.). Patients suffering from occult hyperthyroidism reacted with an increase of urinary thyroxine and histamine as soon as a weather front arrived with the clinical signs of slight hyperthyroidism, especially tachycardia. The serotonin irritation syndrome and the hyperthyroidism were prevented and cured by negative air ionisation treatment in 75% or 45% of the cases respectively. 相似文献
552.
The DNA sequence of the 5.7 kb plasmid pHH9 containing the replicon region of the 150 kb plasmid pHH1 from Halobacterium salinarium was determined. The minimal region necessary for stable plasmid maintenance lies within a 2.9 kb fragment, as defined by transformation experiments. The DNA sequence contained two open reading frames arranged in opposite orientations, separated by an unusually high AT-rich (60–70% A + T) sequence of 350 bp. All H. salinarium strains (H. halobium, H. cutirubrum) investigated harbour endogenous plasmids containing the pHH1 replicon; however, these pHH1-type plasmids differ by insertions and deletions. Adjacent to the replicon, and separated by a copy of each of the insertion elements ISH27 and ISH26, is the 9 kb p-vac region required for gas vesicle synthesis. Analysis of these and other ISH element copies in pHH1 revealed that most of them lack the target DNA duplication usually found with recently transposed ISH elements. These results underline the plasticity of plasmid pHH1. 相似文献
553.
Introduction of intersubunit disulfide bonds in the membrane-distal region of the influenza hemagglutinin abolishes membrane fusion activity. 总被引:12,自引:0,他引:12
L Godley J Pfeifer D Steinhauer B Ely G Shaw R Kaufmann E Suchanek C Pabo J J Skehel D C Wiley 《Cell》1992,68(4):635-645
Influenza virus hemagglutinin (HA) mediates viral entry into cells by a low pH-induced membrane fusion event in endosomes. A number of structural changes occur throughout the length of HA at the pH of fusion. To probe their significance and their necessity for fusion activity, we have prepared a site-directed mutant HA containing novel intersubunit disulfide bonds designed to cross-link covalently the membrane-distal domains of the trimer. These mutations inhibited the low pH-induced conformational changes and prevented HA-mediated membrane fusion; conditions that reduced the novel disulfide bonds restored membrane fusion activity. We conclude that structural rearrangements in the membrane distal region of the HA are required for membrane fusion activity. 相似文献
554.
Partial 18S rRNA sequences of five chelicerate arthropods plus a
crustacean, myriapod, insect, chordate, echinoderm, annelid, and
platyhelminth were compared. The sequence data were used to infer phylogeny
by using a maximum-parsimony method, an evolutionary-distance method, and
the evolutionary-parsimony method. The phylogenetic inferences generated by
maximum-parsimony and distance methods support both monophyly of the
Arthropoda and monophyly of the Chelicerata within the Arthropoda. These
results are congruent with phylogenies based on rigorous cladistic analyses
of morphological characters. Results support the inclusion of the
Arthropoda within a spiralian or protostome coelomate clade that is the
sister group of a deuterostome clade, refuting the hypothesis that the
arthropods represent the "primitive" sister group of a protostome coelomate
clade. Bootstrap analyses and consideration of all trees within 1% of the
length of the most parsimonious tree suggest that relationships between the
nonchelicerate arthropods and relationships within the chelicerate clade
cannot be reliably inferred with the partial 18S rRNA sequence data. With
the evolutionary-parsimony method, support for monophyly of the Arthropoda
is found in the majority of the combinations analyzed if the coelomates are
used as "outgroups." Monophyly of the Chelicerata is supported in most
combinations assessed. Our analyses also indicate that the
evolutionary-parsimony method, like distance and parsimony, may be biased
by taxa with long branches. We suggest that a previous study's inference of
the Arthropoda as paraphyletic may be the result of (a) having two few
arthropod taxa available for analysis and (b) including long-branched taxa.
相似文献
555.
C Minimo P H Bartels D H Kim T Pfeifer H E Dytch H Galera-Davidson M Bibbo 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1991,13(6):411-417
Architectural and histometric features for the objective grading of prostate adenocarcinoma in histologic specimens were analyzed in five cases each of Gleason primary grades 2, 3A, 3B, 3C, 4A and 4B, selected as "typical" for the histopathologic images. Tissue sections from the selected cases were stained by the Feulgen method. Fifteen fields for each grade, for a total of 4,430 glands, were digitized by a video-based microphotometer at low resolution (pixel spacing of 2 microns). Outer and inner outlines of the glandular epithelium were traced manually using a mouse. For each field the number of glands, the gland area, the lumen area, the area of the glandular epithelium and the cribriformity factor were computed. The gland area and its variance proved to be useful indicators for lower-grade lesions, whereas the variance of cribriformity resulted in an excellent grading indicator in the Gleason 3-4 range when cribriform glands were present. 相似文献
556.
557.
558.
Genome structure of Halobacterium halobium: plasmid dynamics in gas vacuole deficient mutants 总被引:5,自引:0,他引:5
Halobacterium halobium contains two gas vacuole protein genes that are located in plasmid pHH1 (p-vac) and in the chromosomal DNA (c-vac). The mutation frequency for these genes is different: the constitutively expressed p-vac gene is mutated with a frequency of 10(-2), while the chromosomal gene expressed in the stationary phase of growth is mutated with a frequency of 10(-5). The difference in the mutation susceptibility is due to the dynamics of plasmid pHH1. p-vac gene mutations are caused (i) by the integration of an insertion element or (ii) by a deletion event encompassing the p-vac gene region. In contrast, c-vac mutants analyzed to date incurred neither insertion elements nor deletions. Deletion events within pHH1 occur at high frequencies during the development of a H. halobium culture. The investigation of the fusion regions resulting from deletion events indicates that insertion elements are involved. The analysis of pHH1 deletion variants led to a 4 kilobase pair DNA region containing the origin of replication of the pHH1 plasmid. 相似文献
559.
Functional dissection and sequence of yeast HAP1 activator 总被引:50,自引:0,他引:50
560.
Polypeptide composition and an immunological analysis of DNA methyltransferases from different species 总被引:1,自引:0,他引:1
G P Pfeifer L Kohlmaier A Tomassetti R Schleicher H Follmann A Pfohl-Leszkowicz G Dirheimer D Drahovsky 《Archives of biochemistry and biophysics》1989,268(1):388-392
The cross-reactivity of the monoclonal anti-human placental DNA methyltransferase antibody M2B10 with DNA methyltransferases isolated from other species was investigated. This antibody immunoprecipitates DNA methyltransferases from mammalian cells, i.e., human placenta, mouse P815 cells, and rat liver cells. No cross-reactivity is observed with DNA methyltransferases from wheat germ and with bacterial DNA methyltransferases HpaII and EcoRI. The mammalian enzymes are characterized by polypeptides of molecular mass 150-190 kDa. Polypeptides smaller than 190 kDa are presumably generated by proteolysis of the native 190-kDa DNA methyltransferase. Trypsin digestion of the 190-kDa polypeptide isolated from mouse cells results in progressive appearance of DNA methyltransferase polypeptides of 150-190, 110, 100, and 52-60 kDa. 相似文献