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991.
The outer-membrane protein ShlB of Serratia marcescens activates and secretes hemolytic ShlA into the culture medium. Without ShlB, inactive ShlA (termed ShlA*) remains in the
periplasm. Since Proteus mirabilis L-form cells lack an outer membrane and a periplasm, it was of interest to determine in which compartment recombinant ShlA*
and ShlB are localized and whether ShlB activates ShlA*. The cloned shlB and shlA genes were transcribed in P. mirabilis stable L-form cells by the temperature-inducible phage T7 RNA polymerase. Radiolabeling, Western blotting, and complementation
with C-terminally truncated ShlA (ShlA255) identified inactive ShlA* in the culture supernatant. ShlB remained cell-bound
and did not activate ShlA without integration in an outer membrane. Although hemolytic ShlA added to L-form cells had access
to the cytoplasmic membrane, it did not affect L-form cells. Synthesis of the large ShlA protein (165 kDa) in P. mirabilis L-form cells under phage T7 promoter control demonstrates that L-form cells are suitable for the synthesis and secretion
of large recombinant proteins. This property and the easy isolation of released proteins make L-form cells suitable for the
biotechnological production of proteins.
Received: 17 February 1998 / Accepted: 30 June 1998 相似文献
992.
Yitang Yan Geert Smant Jack Stokkermans Ling Qin Johannes Helder Thomas Baum Arjen Schots Eric Davis 《Gene》1998,220(1-2):61-70
The genomic organization of genes encoding β-1,4-endoglucanases (cellulases) from the plant-parasitic cyst nematodes Heterodera glycines and Globodera rostochiensis (HG-eng1, Hg-eng2, GR-eng1, and GR-eng2) was investigated. HG-eng1 and GR-eng1 both contained eight introns and structural domains of 2151 and 2492 bp, respectively. HG-eng2 and GR-eng2 both contained seven introns and structural domains of 2324 and 2388 bp, respectively. No significant similarity in intron sequence or size was observed between HG-eng1 and HG-eng2, whereas the opposite was true between GR-eng1 and GR-eng2. Intron positions among all four cyst nematode cellulase genes were conserved identically in relation to the predicted amino acid sequence. HG-eng1, GR-eng1, and GR-eng2 had several introns demarcated by 5′-GC…AG-3′ in the splice sites, and all four nematode cellulase genes had the polyadenylation and cleavage signal sequence 5′-GAUAAA-3′—both rare occurences in eukaryotic genes. The 5′- flanking regions of each nematode cellulase gene, however, had signature sequences typical of eukaryotic promoter regions, including a TATA box, bHLH-type binding sites, and putative silencer, repressor, and enhancer elements. Database searches and subsequent phylogenetic comparison of the catalytic domain of the nematode cellulases placed the nematode genes in one group, with Family 5, subfamily 2, glycosyl hydrolases from Scotobacteria and Bacilliaceae as the most homologous groups. The overall amino acid sequence identity among the four nematode cellulases was from 71 to 83%, and the amino acid sequence identity to bacterial Family 5 cellulases ranged from 33 to 44%. The eukaryotic organization of the four cyst nematode cellulases suggests that they share a common ancestor, and their strong homology to prokaryotic glycosyl hydrolases may be indicative of an ancient horizontal gene transfer. 相似文献
993.
Seventeen patients with metastatic breast carcinoma were treated with a combination of 5-fluorouracil, methotrexate, vincristine, cyclophosphamide and prednisone. Six of the patients (35%) developed a syndrome consisting of fever, malaise, dyspnea, hypoxemia and bilateral pulmonary interstitial infiltrates from 41 to 148 days after institution of therapy. The syndrome varied from a mild to a life-threatening illness with recovery in 10 to 60 days. It is believed that these cases represent examples of methotrexate-induced pneumonitis. The high incidence of the syndrome in this patient group may be related to the concomitant administration of cyclophosphamide with methotrexate. The observations also suggest that patients with previous adrenalectomies may have pneumonitis with an especially severe and protracted course. 相似文献
994.
Summary A 13-year-old boy with 47 chromosomes, an extra small metacentric chromosome and karyotype 47,XY,?Yq- is presented. He has psychiatric symptoms typical of boys with karyotype 47,XYY as seen in the tabulated results of a psychiatric study of 22 boys with the XYY syndrome, examined at the Cytogenetic Laboratory, Århus State Hospital, Risskov.
Zusammenfassung Es wird über einen 13 Jahre alten Jungen berichtet mit 47 Chromosomen, einem zusätzlichen kleinen metazentrischen Chromosom und der Karyotype 47,XY, ?Yq-. Er weist die typischen psychischen Symptome für Jungen mit der Karyotype 47,XYY auf, wie man aus den tabellarisch dargestellten Ergebnissen der psychiatrischen Untersuchung von insgesamt 22 Jungen mit XYY-Syndrom, die am cytogenetischen Labor, Århus State Hospital, Risskov, untersucht wurden, ersehen kann.相似文献
995.
The constitution of five new compounds, (?)-neorautenol, (?)-neodunol, (?)-homoedudiol, neorauteen and neoduleen, has been established in the root bark of Neorautanenia edulis. 相似文献
996.
997.
Summary Tips of fronds of Fucus serratus L. were exposed to H14CO3 in the light for periods of 10, 30, 60, and 180s, fixed in petrol ether at-70° C, and subsequently lyophilized. Pheoplasts (=chloroplasts) were isolated using the nonaqueous technique of Thalacker et al. (1959). After extraction and chromatography percentage 14C activity and distribution of individual photoassimilates between pheoplasts and other compartments of assimilating cells were analyzed. Eighty percent of [14C]-phosphate esters were found within the pheoplasts after 10s 14C-assimilation, whereas only 25% were found there after 30s. After 10s [14C] mannitol is almost totally localized within the plastids, but after 180s the major part has been localized outside the pheoplasts. On the basis of these data the pheoplasts are regarded to be the only sites of primary mannitol biosynthesis during photosynthesis in Fucus. 相似文献
998.
Summary Presumptive isochromosome short arms-satellites D or G was found in a father and his daughter, both of whom had personality deviation. The father was detected in a prevalence and incidence study of 1208 males in a Danish psychiatric hospital.It is concluded that there is most probably no causal relationship between the presumptive isochromosome short arms-satellites of a D or a G chromosome and the personality deviation in the proband and his daughter in the present study.
Zusammenfassung Bei einem Vater und seiner Tochter fand sich ein Extra-Chromosom, das wahrscheinlich ein Isochromosom von kurzen Armen bzw. Satelliten von D- oder G-Chromosomen darstellt. Beide hatten eine Anomalie der Persönlichkeit. Der Vater wurde in einer Prävalenz- und Incidenzstudie an 1208 Männern eines dänischen Psychiatrischen Hospitals erfaßt.Die Autoren ziehen den Schluß, daß sehr wahrscheinlich keine kausale Beziehung zwischen dem vermuteten Isochromosom und der Persönlichkeitsabweichung bei dem Probanden und seiner Tochter besteht.相似文献
999.
1000.