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351.
Identification and Characterization of an N-Methyl-D-Aspartate-Specific L-[3 H]Glutamate Recognition Site in Synaptic Plasma Membranes 总被引:1,自引:0,他引:1
Conditions have been developed for an L-[3H]glutamate binding assay in which 85-95% of the specific binding is to a site that corresponds to the N-methyl-D-aspartate subclass of acidic amino acid receptors. Incubation of synaptic plasma membranes with L-[3H]glutamate in 50 mM Tris/acetate, pH 7.4, for 2-20 min at 2 degrees C results in binding with pharmacological characteristics of the electrophysiologically defined N-methyl-D-aspartate receptor. The fraction of glutamate binding to this subclass of receptors, relative to the total, decreases with both increased time and temperature. This binding is reversible, is concentrated in the synaptic plasma membrane fraction, has a pH optimum of 7.0-7.4, and is linear with respect to tissue protein concentration. The binding is unaffected by 1 mM concentrations of the anions sulfate, chloride, bromide, thiocyanate, phosphate, acetate, nitrate, or carbonate and the monovalent cations potassium or ammonium. However sodium and the divalent cations copper, cobalt, zinc, cadmium, and manganese decrease binding to this N-methyl-D-aspartate site. 相似文献
352.
An overview of the phanerogamic and cryptogamic collections accumulated by The New York Botanical Garden Herbarium (NY) since its foundation in 1891 is presented. Appended are a list of herbaria incorporated into NY, a list of collectors who have deposited their original herbaria or significant parts thereof at NY, a list of the taxonomic groups particularly well represented at NY, and a list of papers published since 1963 about the NY collections. 相似文献
353.
William A. Schutt Matthew A. Cobb Jacquelyn L. Petrie John W. Hermanson 《Journal of morphology》1994,220(3):295-305
The ontogeny of a primary flight muscle, the pectoralis, in the little brown bat (Myotis lucifugus: Vespertilionidae) was studied using histochemical, immunocytochemical, and electrophoretic techniques. In fetal and early neonatal (postnatal age 1–6 days) Myotis, histochemical techniques for myofibrillar ATPase (mATPase) and antibodies for slow and fast myosins demonstrated the presence of two fiber types, here called types I and IIa. These data correlated with multiple transitional myosin heavy chain isoforms and native myosin isoforms demonstrated with SDS-PAGE and 4% pyrophosphate PAGE. There was a decrease in the distribution and number of type I fibers with increasing postnatal age. At postnatal age 8–9 days, the adult phenotype was observed with regard to muscle fiber type (100% type IIa fibers) and myosin isoform profile (single adult MHC and native myosin isoforms). This “adult” fiber type profile and myosin isoform composition preceeded adult function by about 2 weeks. For example, little brown bats were incapable of sustained flight until approximately postnatal day 24, and myofiber size did not achieve adult size until approximately postnatal day 25. Although Myotis pectoralis is unique in being composed of 100% type IIa fibers, transitional fiber types and isoforms were present. These transitional forms had been observed previously in other mammals bearing mixed adult muscle fibers and which undergo transitional stages in muscle ontogeny. However, in Myotis pectoralis, this transition transpires relatively early in development. © 1994 Wiley-Liss, Inc. 相似文献
354.
Deborah A. Sampson Dennis Caldwell Andre D. Taylor Jacquelyn Y. Taylor 《The Yale journal of biology and medicine》2013,86(1):89-98
In this paper, we examine the implementation and difficulties when conducting
genetics research in a rural, traditional West African culture within the frame
of the United States’ grounded research ethics. Research challenges are
highlighted by Western researchers following U.S. Institutional Review Board
(IRB) guidelines and practices in a non-Western country. IRB concepts are
culture bound in Western ideals that may not have synchronicity and
compatibility with non-Western cultures. Differences in sociocultural norms,
traditions, language, and geography were influencing factors that can affect
application of IRB principles. Suggestions for change are offered, which will
potentially aid researchers considering application of IRB requirements when
conducting research in non-Westernized, non-industrialized countries. 相似文献
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Tyrone J. Summers James W. Thomas Shih-Queen Lee-Lin Valerie V.B. Maduro Jacquelyn R. Idol Eric D. Green 《Mammalian genome》2001,12(7):508-512
The comparative mapping and sequencing of vertebrate genomes is now a key priority for the Human Genome Project. In addition
to finishing the human genome sequence and generating a `working draft' of the mouse genome sequence, significant attention
is rapidly turning to the analysis of other model organisms, such as the laboratory rat (Rattus norvegicus). As a complement to genome-wide mapping and sequencing efforts, it is often important to generate detailed maps and sequence
data for specific regions of interest. Using an adaptation of our previously described approach for constructing mouse comparative
and physical maps, we have established a general strategy for targeted mapping of the rat genome. Specifically, we constructed
a framework comparative map of human Chromosome (Chr) 7 and the orthologous regions of the rat genome, as well as two large
(>1-Mb) P1-derived artificial chromosome (PAC)-based physical maps. Generation of these physical maps involved the use of
mouse-derived probes that cross-hybridized with rat PAC clones. The first PAC map encompasses the cystic fibrosis transmembrane
conductance regulator gene (Cftr), while the second map allows a three-species comparison of a genomic region containing intra- and inter-chromosomal evolutionary
rearrangements. The studies reported here further demonstrate that cross-species hybridization between related animals, such
as rat and mouse, can be readily used for the targeted construction of clone-based physical maps, thereby accelerating the
analysis of biologically interesting regions of vertebrate genomes.
Received: 5 December 2000 / Accepted: 27 February 2001 相似文献
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