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排序方式: 共有294条查询结果,搜索用时 31 毫秒
31.
Delane C. Kritsky Stephen A. Bullard Carlos F. Ruiz Micah B. Warren 《Systematic parasitology》2017,94(7):777-784
A new species of Empruthotrema Johnston & Tiegs, 1922 is described based on specimens collected from the olfactory sacs of smooth butterfly rays Gymnura micrura (Bloch & Schneider) captured in Mobile Bay (northcentral Gulf of Mexico), Alabama, USA. Empruthotrema longipenis n. sp. is most similar to the type-species Empruthotrema raiae (MacCallum, 1916) Johnston & Tiegs, 1922 by having 12 marginal and two interhamular loculi with members of haptoral hook pair 1 located midway along the periphery of each interhamular loculus and those of hook pair 2 located at the marginal termini of the bilateral septa flanking the interhamular loculi. Empruthotrema longipenis n. sp. differs from E. raiae by having a much longer male copulatory organ and from its remaining congeners by the sinistral and extracecal ejaculatory bulb flanking the pharynx, the number of interhamular and marginal septa, and the distribution of hook pairs 1 and 2 along the haptoral margin. This is the first report of a monocotylid from the smooth butterfly ray and from Mobile Bay. The diversity of haptoral morphotypes among the currently accepted species of Empruthotrema is detailed and discussed in the context of monophyly of the genus. 相似文献
32.
The availability of human stem cells heralds a new era for modeling normal and pathologic tissues and developing therapeutics. For example, the in vitro recapitulation of normal and aberrant neurogenesis holds significant promise as a tool for de novo modeling of neurodevelopmental and neurodegenerative diseases. Translational applications include deciphering brain development, function, pathologies, traditional medications, and drug discovery for novel pharmacotherapeutics. For the latter, human stem cell-based assays represent a physiologically relevant and high-throughput means to assess toxicity and other undesirable effects early in the drug development pipeline, avoiding late-stage attrition whilst expediting proof-of-concept of genuine drug candidates. Here we consider the potential of human embryonic, adult, and induced pluripotent stem cells for studying neurological disorders and preclinical drug development. 相似文献
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34.
Spangenburg Espen E. Brown David A. Johnson Micah S. Moore Russell L. 《Molecular and cellular biochemistry》2009,331(1-2):225-230
Molecular and Cellular Biochemistry - Reticulon3 (RTN3), as a member of the reticulon family, is generally regarded as a novel human apoptosis-inducing protein. But the extensional role of RTN3... 相似文献
35.
Micah Dunthorn 《Plant Systematics and Evolution》2009,280(3-4):153-166
Anatomical observations of the petiole and lamina of Mammea L. (Clusiaceae, Kielmeyeroideae) show extensive variation. All species have a complex folding pattern of the vascular bundle within the petiole, differing from most of the patterns found in the rest of the family. Except for the species found in the Neotropics and Africa, the laminas of almost all species contain fibers not immediately associated with the vascular tissue—a unique feature in the Clusiaceae. Fiber motifs range from bundles originating within the petiole, sheets forming an almost contiguous layer, to fibers with various patterns of organization derived from the secondary veins. Species groups based on fiber motif are recognized, and these correlate with other anatomical and morphological characters. 相似文献
36.
Donna L Montgomery Ying-Jie Wang Renee Hrin Micah Luftig Bin Su Michael D Miller Fubao Wang Peter Haytko Lingyi Huang Salvatore Vitelli Jon Condra Xiaomei Liu Richard Hampton Andrea Carfi Antonello Pessi Elisabetta Bianchi Joseph Joyce Chris Lloyd Romas Geleziunas David Bramhill Vicki M King Adam C Finnefrock William Strohl Zhiqiang An 《MABS-AUSTIN》2009,1(5):462-474
The human D5 monoclonal antibody binds to the highly conserved hydrophobic pocket on the N-terminal heptad repeat (NHR) trimer of HIV-1 gp41 and exhibits modest yet relatively broad neutralization activity. Both binding and neutralization depend on residues in the complementarity determining regions (CDRs) of the D5 IgG variable domains on heavy chain (VH) and light chain (VL). In an effort to increase neutralization activity to a wider range of HIV-1 strains, we have affinity matured the parental D5 scFv by randomizing selected residues in 5 of its 6 CDRs. The resulting scFv variants derived from four different CDR changes showed enhanced binding affinities to gp41 NHR mimetic (5-helix) which correlated to improved neutralization potencies by up to 8-fold. However, when converted to IgG1s, these D5 variants had up to a 12-fold reduction in neutralization potency over their corresponding scFvs despite their slightly enhanced in vitro binding affinities. Remarkably, D5 variant IgG1s bearing residue changes in CDRs that interact with epitope residues N-terminal to the hydrophobic pocket (such as VH CDR3 and VL CDR3) retained more neutralization potency than those containing residue changes in pocket-interacting CDRs (such as VH CDR2). These results provide compelling evidence for the existence of a steric block to an IgG that extends to the gp41 NHR hydrophobic pocket region, and can be a useful guide for developing therapeutic antibodies and vaccines circumventing this block. 相似文献
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39.
Bindi Dangi Marcus Obeng Julie M. Nauroth Mah Teymourlouei Micah Needham Krishna Raman Linda M. Arterburn 《The Journal of biological chemistry》2009,284(22):14744-14759
Enzymatically oxygenated derivatives of the ω-3 fatty acids
cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) and
cis-5,8,11,14,17-eicosapentaenoic acid, known as resolvins, have
potent inflammation resolution activity (Serhan, C. N., Clish, C. B., Brannon,
J., Colgan, S. P., Chiang, N., and Gronert, K. (2000) J. Exp. Med.
192, 1197–1204; Hong, S., Gronert, K., Devchand, P. R., Moussignac, R.,
and Serhan, C. N. (2003) J. Biol. Chem. 278,
14677–14687). Our objective was to determine whether similar derivatives
are enzymatically synthesized from other C-22 fatty acids and whether these
molecules possess inflammation resolution properties. The reaction of DHA,
DPAn-3, and DPAn-6 with 5-, 12-, and 15-lipoxygenases produced oxylipins,
which were identified and characterized by liquid chromatography coupled with
tandem mass-spectrometry. DPAn-6 and DPAn-3 proved to be good substrates for
15-lipoxygenase. 15-Lipoxygenase proved to be the most efficient enzyme of the
three tested for conversion of long chain polyunsaturated fatty acids to
corresponding oxylipins. Since DPAn-6 is a major component of Martek
DHA-S™ oil, we focused our attention on reaction products obtained from
the DPAn-6 and 15-lipoxygenase reaction. (17S)-hydroxy-DPAn-6 and
(10,17S)-dihydroxy-DPAn-6 were the main products of this reaction.
These compounds were purified by preparatory high performance liquid
chromatography techniques and further characterized by NMR, UV
spectrophotometry, and tandem mass spectrometry. We tested both compounds in
two animal models of acute inflammation and demonstrated that both compounds
are potent anti-inflammatory agents that are active on local intravenous as
well as oral administration. These oxygenated DPAn-6 compounds can thus be
categorized as a new class of DPAn-6-derived resolvins.Enzymatically formed oxygenation products of C-20 and C-22 long chain
polyunsaturated fatty acids
(LC-PUFAs),4 have
important biological roles in inflammation, allergies, and blood clotting and
are thus believed to have therapeutic potential in several chronic immune
diseases
(1–10)
Several biologically important products of
cis-5,8,11,14-eicosatetraenoic acid/arachidonic acid (ARA),
cis-5,8,11,14,17-eicosapentaenoic acid (EPA), and
cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) have been described
(4,
11,
12). Proinflammatory
oxylipins, such as leukotrienes and some prostaglandins, are derived from ARA,
an ω-6 fatty acid. Interestingly, the same fatty acid also serves as a
precursor to anti-inflammatory or proresolution molecules like lipoxins
(13,
14). Stable analogues of
lipoxins are being developed as drugs for asthma and other inflammatory airway
diseases (15,
16). Oxylipins derived from
ω-3 fatty acids, such as DHA and EPA, known as resolvins, are primarily
anti-inflammatory in nature
(17). EPA acts as a precursor
to the E-series resolvins that have shown potential in the treatment of
colitis, arthritis, and periodontitis
(18–20).
The resolvins of the D-series derived from DHA are useful as neuroprotective
agents. 10,17-Dihydroxy-4,7,11,13,15,19-docosahexaenoic acid (10,17-HDHA) or
neuroprotectin D1 is a resolvin that is formed endogenously in the human brain
and eye and is believed to exert its protective effect against cell
injury-induced oxidative stress
(21–23).The main enzymes responsible for the production of these oxygenated LC-PUFA
products are primarily lipoxygenases and, in addition, cyclo-oxygenases and
cytochromes P450. These enzymes produce oxylipins via transcellular activity,
often involving multiple cell types
(24). This activity mainly
results in mono-, di-, and tri-hydroxylation products of fatty acids that have
varying potencies, depending on the exact structure of the compound.
Lipoxygenases are non-heme, iron-containing dioxygenases that catalyze the
regioselective and enantioselective oxidation of polyunsaturated fatty acids
containing one or more cis,cis-1,4-pentadienoic moieties to give the
corresponding hydroperoxy derivatives
(25,
26). We thus considered that,
in addition to DHA and EPA, other C-22 PUFAs containing such methylene
interrupted double bonds may also be substrates for lipoxygenases and that
resulting products may have anti-inflammatory activity similar to DHA-derived
resolvins. DPAn-6 (cis-4,7,10,13,16-docosapentaenoic acid) is present
in algal oils, and recent studies have demonstrated that this fatty acid has
anti-inflammatory activities in vitro and, in conjunction with DHA,
also has anti-inflammatory activity in
vivo.5 Also, it
has been suggested that a combination of DHA and DPAn-6 could be a beneficial
natural therapy in neuroinflammatory conditions like Alzheimer disease.
Specifically, in a 3×Tg-AD mouse model of Alzheimer disease, DPAn-6 was
shown to reduce levels of early stage phospho-Tau epitopes, which in turn
correlated with a reduction in phosphorylated c-Jun N-terminal kinase, a
putative Tau kinase (27).
Although the precise mechanism of action of DPAn-6 in these inflammatory
milieus is not known, it suggests a possible role for oxylipin products of
DPAn-6 in resolution of inflammation. Also, another LC-PUFA, DPAn-3
(cis-7,10,13,16,19-docosapentaenoic acid) usually present along with
DHA and EPA in marine oils is known to be a potent inhibitor of platelet
aggregation
(28–30).
In addition, this LC-PUFA has a potent inhibitory effect on angiogenesis
through the suppression of VEGFR-2 (vascular endothelial-cell growth factor
receptor 2) expression. Angiogenesis is known to contribute to tumor growth,
inflammation, and microangiopathy, again pointing to the possibility that
anti-inflammatory activity of DPAn-3 might be mediated through resolvin-like
products as in the case of DHA and EPA
(31).The purpose of this research was to determine whether oxylipins are formed
from the C-22 LC-PUFAs, DPAn-6 and DPAn-3, by lipoxygenase activity; to
compare them to products formed from DHA; to chemically characterize products;
to purify key oxylipin products from the DPAn-6/15-lipoxygenase reaction; and
to test whether these compounds have resolvin-like anti-inflammatory activity.
This research also sets the stage for preparation and isolation of a wide
range of other C-22 oxylipins that could be evaluated as potential
anti-inflammatory compounds. 相似文献
40.
Grace X. Ma Steve Shive Yin Tan Wanzhen Gao Joanne Rhee Micah Park Jaesool Kim Jamil I. Toubbeh 《Cancer epidemiology》2009,33(5):381-386
Background: Despite evidence of a decline in both incidence and prevalence of colorectal cancer nationwide, it remains the second most commonly diagnosed cancer and the third highest cause of mortality among Asian Americans, including Korean Americans. This community-based and theoretically guided study evaluated a culturally appropriate intervention program that included a bilingual cancer educational program among Korean Americans including information on CRC risks, counseling to address psychosocial and access barriers, and patient navigation assistance. Methods: A two-group quasi-experimental design with baseline and post-intervention assessment and a 12-month follow-up on screening was used in the study. Korean Americans (N = 167) were enrolled from six Korean churches. The intervention group received culturally appropriate intervention program addressing accessibility and psychosocial barriers, and navigation assistance for screening. The control group received general health education that included cancer-related health issues and screening. Results: There was a significant difference (p < 0.05) between the post-intervention and control groups in awareness of CRC risk factors. There was also a significant improvement in the pre–post across HBM measures in the intervention group for perceived susceptibility (p < 0.05) and benefits and barriers to screening (p < 0.001). At baseline, 13% of participants in the intervention group and 10% in control group reported having had a CRC cancer screening test in the previous year. At the 12-month post-intervention follow-up, 77.4% of participants in the intervention group had obtained screening compared to 10.8% in the control group. Conclusion: While health disparities result from numerous factors, a culturally appropriate and church-based intervention can be highly effective in increasing knowledge of and access to, and in reducing barriers to CRC screening among underserved Koreans. 相似文献