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51.
CM Ward AP Wilkinson S Bramham HA Lee HW-S Chan GW Butcher A Hutchings MRA Morgan 《Mycotoxin Research》1990,6(2):73-83
From a single aflatoxin B1 oxime — bovine serum albumin conjugate, polyclonal and monoclonal antibody preparations were produced. The four rabbit polyclonal antisera were specific for aflatoxin Bi in a microtitration plate enzyme — linked immunosorbent assay. The monoclonal antibodies showed a wide range of differing specificities, recognizing, for example, aflatoxins B1, B2, G1 and G2; B1 and B2; B1 and G1; and G1 alone. No antibody preparations reacted with aflatoxin M1. The significance of these results to the strategy of anti-aflatoxin antibody production for use in quantitative enzyme immunoassays is discussed. 相似文献
52.
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54.
Effects of PCB on interspecific competition in natural and gnotobiotic phytoplankton communities in continuous and batch cultures 总被引:1,自引:0,他引:1
Nicholas S. Fisher Ph.D. candidate Edward J. Carpenter Charles C. Remsen Charles F. Wurster 《Microbial ecology》1974,1(1):39-50
The toxicity of polychlorinated biphenyls (PCB) to the diatomThalassiosira pseudonana (formerlyCyclotella nana), grown in pure and mixed cultures, was greatest when in competition with other species. Continuous cultures were superior
to batch cultures for studying competitive interactions, and PCB caused greater alteration of species composition in continuous
cultures than it did in batch cultures. Natural phytoplankton communities from Vineyard Sound, maintained in continuous culture,
responded to PCB stress the same as did gnotobiotic communities, withT. pseudonana showing similar responses in both communities.
A PCB concentration of 0.1 μg/liter (0.1 part per billion), a level not uncommon in natural waters, did not affect algal growth
in pure cultures but caused substantial disruption of continuous culture communities. The possible impact of PCB pollution
on natural phytoplankton communities is discussed.
Contribution No. 3181 from the Woods Hole Oceanographic Institution. 相似文献
55.
Fr. -K. Pierau R. D. Wurster T. Neya T. Yamasato J. Ulrich 《International journal of biometeorology》1980,24(3):243-252
Temperature transduction in peripheral cold receptors and processing of peripheral temperature signals in the spinal cord were studied in cats and rats. The temperature dependence of the generator potential is attributed to different temperature coefficients of an electrogenic Na-efflux and the passive Na-influx. Cold receptor activity and particularly its bursting pattern is considerably modulated by the local Ca-concentration, but the effect of elevated Ca-concentration is abolished by the ATPase blocker ouabain. — The peripheral temperature signals from the scrotal skin of rats are transformed in dorsal horn neurones (DHN) into temperature reactions, which occur only above (warm reaction) or below (cold reaction) a certain temperature threshold and are limited to an operational range of 1–4°C. Convergency of different temperature inputs were observed in one and the same DHN. Supraspinal control of temperature reactive DHN appears to be complex but predominantly excitatory.Presented at the Eighth International Congress of Biometeorology, 9–14 September 1979, Shefayim, Israel. 相似文献
56.
Unusually large sex chromosomes in the sitatunga (Tragelaphus spekei) and the blackbuck (Antilope cervicapra) 总被引:1,自引:0,他引:1
Sex chromosomes in mammals are generally of the XY type with the X chromosome constituting 5% by weight of the haploid chromosomal complement. Unusually large sex chromosomes have been described in a few species all of which belong to theRodentia, but two members of theArtiodactyla, the African sitatunga and the Indian blackbuck, have now been found to have this peculiarity. The sitatunga has an X chromosome that represents 13.08% and a Y that represents 7.29% of the haploid complement, and the X of the blackbuck represents 14.96% of its haploid complement. Portions of both extra large sex chromosomes in a pair are late replicating. Theories concerning the formation of these outsized chromosomes are discussed. 相似文献
57.
H P Thalhofer W Starz G Daum B Wurster B G Harris H W Hofer 《Archives of biochemistry and biophysics》1989,271(2):471-478
The cyclic 3',5'-AMP-binding protein was isolated from the muscle of Ascaris suum and purified to apparent homogeneity. It migrated as a protein with a relative Mr 54,000 on electrophoresis under denaturing conditions. On gel filtration columns it was eluted at a volume corresponding to a protein of Mr greater than 200,000 under conditions which kept the cyclic 3',5'-AMP-binding property intact. The purified catalytic subunit of protein kinase from Ascaris and the C subunit of cyclic 3',5'-AMP-dependent protein kinase from bovine heart were inhibited by the cyclic 3',5'-AMP-binding protein. Gel filtration studies indicated the formation of a stable protein complex between the protein kinase and the cyclic 3',5'-AMP-binding protein from Ascaris. 相似文献
58.
Teng YK Verburg RJ Verpoort KN Diepenhorst GM Bajema IM van Tol MJ Jol-van der Zijde EC Toes RE Huizinga TW van Laar JM 《Arthritis research & therapy》2007,9(5):R106
In order to identify pathogenic correlates of refractory rheumatoid arthritis (RA), antibodies against anti-cyclic citrullinated
protein (ACPAs) were investigated in RA patients in whom the dysregulated immune system had been ablated by high-dose chemotherapy
(HDC) and autologous haematopoietic stem cell transplantation (HSCT). Six patients with refractory RA were extensively characterized
in terms of levels of total immunoglobulins, RA-specific autoantibodies (ACPAs and rheumatoid factor) and antibodies against
rubella, tetanus toxoid (TT) and phosphorylcholine before and after HDC plus HSCT. Additionally, the avidity of ACPAs was
measured before and after treatment and compared with the avidity of TT antibodies following repeated immunizations. Synovial
biopsies were obtained by arthroscopy before HDC plus HSCT, and analyzed by immunohistochemistry. In the three patients with
clinically long-lasting responses to HDC plus HSCT (median 423 days), significant reductions in ACPA-IgG levels after therapy
were observed (median level dropped from 215 to 34 arbitrary units/ml; P = 0.05). In contrast, stable ACPA-IgG levels were observed in three patients who relapsed shortly after HDC plus HSCT (median
of 67 days). Clinical responders had ACPA-IgG of lower avidity (r = 0.75; P = 0.08) and higher degree of inflammation histologically (r = 0.73; P = 0.09). Relapse (after 38 to 530 days) in all patients was preceded by rising levels of low avidity ACPA-IgG (after 30 to
388 days), in contrast to the stable titres of high avidity TT antibodies. In conclusion, humoral autoimmune responses were
differentially modulated by immunoablative therapy in patients with synovial inflammation and low avidity ACPA-IgG autoantibodies
as compared with patients with high levels of high avidity ACPA-IgG. The distinct clinical disease course after immunoablative
therapy based on levels and avidity of ACPA-IgG indicates that refractory RA is not a single disease entity. 相似文献
59.
Rens W O'Brien PC Grützner F Clarke O Graphodatskaya D Tsend-Ayush E Trifonov VA Skelton H Wallis MC Johnston S Veyrunes F Graves JA Ferguson-Smith MA 《Genome biology》2007,8(11):R243-21
Background
Sex-determining systems have evolved independently in vertebrates. Placental mammals and marsupials have an XY system, birds have a ZW system. Reptiles and amphibians have different systems, including temperature-dependent sex determination, and XY and ZW systems that differ in origin from birds and placental mammals. Monotremes diverged early in mammalian evolution, just after the mammalian clade diverged from the sauropsid clade. Our previous studies showed that male platypus has five X and five Y chromosomes, no SRY, and DMRT1 on an X chromosome. In order to investigate monotreme sex chromosome evolution, we performed a comparative study of platypus and echidna by chromosome painting and comparative gene mapping.Results
Chromosome painting reveals a meiotic chain of nine sex chromosomes in the male echidna and establishes their order in the chain. Two of those differ from those in the platypus, three of the platypus sex chromosomes differ from those of the echidna and the order of several chromosomes is rearranged. Comparative gene mapping shows that, in addition to bird autosome regions, regions of bird Z chromosomes are homologous to regions in four platypus X chromosomes, that is, X1, X2, X3, X5, and in chromosome Y1.Conclusion
Monotreme sex chromosomes are easiest to explain on the hypothesis that autosomes were added sequentially to the translocation chain, with the final additions after platypus and echidna divergence. Genome sequencing and contig anchoring show no homology yet between platypus and therian Xs; thus, monotremes have a unique XY sex chromosome system that shares some homology with the avian Z. 相似文献60.
Eveline M van den Berg Udo van Dongen Ben Abbas Mark CM van Loosdrecht 《The ISME journal》2015,9(10):2153-2161
Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are competing microbial nitrate-reduction processes. The occurrence of DNRA has been shown to be effected qualitatively by various parameters in the environment. A more quantitative understanding can be obtained using enrichment cultures in a laboratory reactor, yet no successful DNRA enrichment culture has been described. We showed that a stable DNRA-dominated enrichment culture can be obtained in a chemostat system. The enrichment was based on the hypothesis that nitrate limitation is the dominant factor in selecting for DNRA. First, a conventional denitrifying culture was enriched from activated sludge, with acetate and nitrate as substrates. Next, the acetate concentration in the medium was increased to obtain nitrate-limiting conditions. As a result, conversions shifted from denitrification to DNRA. In this selection of a DNRA culture, two important factors were the nitrate limitation and a relatively low dilution rate (0.026 h−1). The culture was a highly enriched population of Deltaproteobacteria most closely related to Geobacter lovleyi, based on 16S rRNA gene sequencing (97% similarity). We established a stable and reproducible cultivation method for the enrichment of DNRA bacteria in a continuously operated reactor system. This enrichment method allows to further investigate the DNRA process and address the factors for competition between DNRA and denitrification, or other N-conversion pathways. 相似文献