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51.
Diers JA Bowling JJ Duke SO Wahyuono S Kelly M Hamann MT 《Marine biotechnology (New York, N.Y.)》2006,8(4):366-372
Several aaptamine derivatives were selected as potential zebra mussel (Dreissena polymorpha) antifoulants because of the noteworthy
absence of fouling observed on Aaptos sponges. Sponges of the genus Aaptos collected in Manado, Indonesia consistently produce
aaptamine-type alkaloids. To date, aaptamine and its derivatives have not been carefully evaluated for their antifoulant properties.
Structure–activity relationship studies were conducted using several aaptamine derivatives in a zebra mussel antifouling assay.
From these data, three analogs have shown significant antifouling activity against zebra mussel attachment. Aaptamine, isoaaptamine,
and the demethylated aaptamine compounds used in the zebra mussel assay produced EC50 values of 24.2, 11.6, and 18.6 μM, respectively. In addition, neither aaptamine nor isoaaptamine produced a phytotoxic response
(as high as 300 μM) toward a nontarget organism, Lemna pausicostata, in a 7-day exposure. The use of these aaptamine derivatives
from Aaptos sp. as potential environmentally benign antifouling alternatives to metal-based paints and preservatives is significant,
not only as a possible control of fouling organisms, but also to highlight the ecological importance of these and similar
biochemical defenses. 相似文献
52.
Tallmadge RL Hopman TJ Schug MD Aquadro CF Bowling AT Murray JD Caetano AR Antczak DF 《Animal genetics》1999,30(6):462-466
This paper describes a fourth set of 20 characterized horse dinucleotide repeat markers developed at Cornell University. 相似文献
53.
54.
Characterization of an Arabidopsis Mutant That Is Nonresponsive to Inducers of Systemic Acquired Resistance 总被引:17,自引:0,他引:17 下载免费PDF全文
Systemic acquired resistance (SAR) is a general defense response in plants that is characterized by the expression of pathogenesis-related (PR) genes. SAR can be induced after a hypersensitive response to an avirulent pathogen or by treatment with either salicylic acid (SA) or 2,6-dichloroisonicotinic acid (INA). To dissect the signal transduction pathway of SAR, we isolated an Arabidopsis mutant that lacks the expression of an SA-, INA-, and pathogen-responsive chimeric reporter gene composed of the 5[prime] untranslated region of an Arabidopsis PR gene, [beta]-1,3-glucanase (BGL2), and the coding region of [beta]-glucuronidase (GUS). This mutant, npr1 (nonexpresser of PR genes), carries a single recessive mutation that abolishes the SAR-responsive expression of other PR genes as well. While SA-, INA-, or avirulent pathogen-induced SAR protects wild-type plants from Pseudomonas syringae infection, the mutant cannot be protected by pretreatment with these inducers. The insensitivity of npr1 to SA, INA, and avirulent pathogens in SAR induction indicates that these inducers share a common signal transduction pathway. Moreover, in npr1, the localized expression of PR genes induced by a virulent Pseudomonas pathogen is disrupted, and the lesion formed is less confined. These results suggest a role for PR genes in preventing the proximal spread of pathogens in addition to their suggested role in SAR. 相似文献
55.
The genomes of homeothermic (warm-blooded) vertebrates are mosaic
interspersions of homogeneously GC-rich and GC-poor regions (isochores).
Evolution of genome compartmentalization and GC-rich isochores is
hypothesized to reflect either selective advantages of an elevated GC
content or chromosome location and mutational pressure associated with the
timing of DNA replication in germ cells. To address the present controversy
regarding the origins and maintenance of isochores in homeothermic
vertebrates, newly obtained as well as published nucleotide sequences of
the insulin and insulin-like growth factor (IGF) genes, members of a
well-characterized gene family believed to have evolved by repeated
duplication and divergence, were utilized to examine the evolution of base
composition in nonconstrained (flanking) and weakly constrained (introns
and fourfold degenerate sites) regions. A phylogeny derived from amino acid
sequences supports a common evolutionary history for the insulin/IGF family
genes. In cold- blooded vertebrates, insulin and the IGFs were similar in
base composition. In contrast, insulin and IGF-II demonstrate dramatic
increases in GC richness in mammals, but no such trend occurred in IGF- I.
Base composition of the coding portions of the insulin and IGF genes across
vertebrates correlated (r = 0.90) with that of the introns and flanking
regions. The GC content of homologous introns differed dramatically between
insulin/IGF-II and IGF-I genes in mammals but was similar to the GC level
of noncoding regions in neighboring genes. Our findings suggest that the
base composition of introns and flanking regions is determined by
chromosomal location and the mutational pressure of the isochore in which
the sequences are embedded. An elevated GC content at codon third positions
in the insulin and the IGF genes may reflect selective constraints on the
usage of synonymous codons.
相似文献
56.
Peter Moller Jacques Serrier Deborah Bowling 《Ethology : formerly Zeitschrift fur Tierpsychologie》1989,82(3):177-191
We investigated the electric organ discharge (EOD) activity of the mormyrid fish Brienomyrus niger during social encounters. The fish were contained in porous ceramic shelters and tested alone and in pairs in an experimental tank designed to restrict communication to the electrosensory modality. We moved one fish toward and away from a stationary conspecific, beginning at a distance known to be outside the range of communication (250 cm). Baseline EOD activity was recorded prior to interaction and categorized as ‘variable’, ‘regular’, and ‘scallop’. When moved closer together, the fish modulated this baseline activity in four ways: (1) At 100–130 cm apart, the stationary fish emitted a maximum of sudden EOD rate increases which defined the outer limit of its communication range. (The associated Electric Field Gradient was 1 μV/cm). (2) Long EOD cessations, which we called social silence, lasted from 5–130 s and occurred most frequently when the fish were 36 to 55 cm apart (EFG: 100 μV/cm). The duration of social silence was negatively correlated (r = ? 0.862) with the responding fish's size, and was independent of the partner's sex and size. Fish whose EOD baseline pattern was ‘scallop’ were least likely to fall electrically silent, and those that were categorized as ‘regular’ or ‘variable’ were most likely to cease discharging. (3) Within electrolocation range, fish ‘regularized’ their EOD activity while the partner was ‘silent’ (EFG: 1 mV/cm). (4) Following long EOD cessations the fish resumed discharging with characteristic EOD rebound patterns. The possible ethological significance of these findings is discussed. 相似文献
57.
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59.
J. David Pinkston C. J. Venkatramani Linda J. Tulich Donald J. Bowling Kenneth R. Wehmeyer 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1993,622(2):209-214
Supercritical fluid chromatography with mass spectrometric detection was evaluated as a technique for the analysis of drugs in biological fluids. Dog plasma was spiked with a model drug, mebeverine, and with a deuterium-labeled analog of mebeverine. The spiked plasma was prepared for analysis by solid-phase extraction on octadecylsilane cartridges. Mebeverine levels in the spiked dog plasma samples were determined by interpolation from a standard curve. Accuracy and precision of the analysis were determined within and between days. In general, accuracy was found to be 100 ± 15% for plasma samples spiked with 6 to 60 ng mebeverine/ml. The relative standard deviation for replicate sample analysis over this concentration range was between 5 and 12.5%. 相似文献
60.
Douglas Boyette C. Bowling Andrew J. Vaughn Kevin C. Hoagland Robert E. Stetina Kenneth C. 《World journal of microbiology & biotechnology》2010,26(5):951-956
World Journal of Microbiology and Biotechnology - In greenhouse experiments, an invert emulsion (MSG 8.25) was tested with spores of the mycoherbicidal fungus Colletotrichum gloeosporioides f. sp.... 相似文献