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111.
Estimates of fossil sirenian body size are important for understanding niche partitioning among possibly sympatric species. Because of the paucity of complete fossil skeletons, we explored the utility of three morphometric predictors of body size: (condylobasal skull length [BSL]; occipital condyle width [OCW]; and foramen magnum width [FMW]) in extant sirenians—Florida manatees (Trichechus manatus latirostris) and dugongs (Dugong dugon)—and then applied these to obtain estimates of body size in extinct sirenian taxa. Condylobasal length of the skull is a more accurate predictor of body size in extant Florida manatees and dugongs than are width of the occipital condyles or width of the foramen magnum. Body length (BL) is predicted more accurately than is body weight (BW) for all three morphometric predictors. For our sample of fossil sirenians, BSL, OCW, and FMW were used to generate predicted BLs and BWs. Preliminary assessments of fossil sirenian faunas from Florida and India suggest that body mass could have been one of several possible important morphological parameters accounting for feeding niche separation. 相似文献
112.
Brian C. Shook Stefanie Rassnick Daniel Hall Kenneth C. Rupert Geoffrey R. Heintzelman Kristen Hansen Devraj Chakravarty James L. Bullington Robert H. Scannevin Brian Magliaro Lori Westover Karen Carroll Lisa Lampron Ronald Russell Shawn Branum Kenneth Wells Sandra Damon Scott Youells Xun Li Mel Osbourne Paul F. Jackson 《Bioorganic & medicinal chemistry letters》2010,20(9):2864-2867
A novel series of arylindenopyrimidines were identified as A2A and A1 receptor antagonists. The series was optimized for in vitro activity by substituting the 8- and 9-positions with methylene amine substituents. The compounds show excellent activity in mouse models of Parkinson’s disease when dosed orally. 相似文献
113.
Steven T. Staben Timothy P. Heffron Daniel P. Sutherlin Seema R. Bhat Georgette M. Castanedo Irina S. Chuckowree Jenna Dotson Adrian J. Folkes Lori S. Friedman Leslie Lee John Lesnick Cristina Lewis Jeremy M. Murray Jim Nonomiya Alan G. Olivero Emile Plise Jodie Pang Wei Wei Prior Laurent Salphati Lionel Rouge Bing-Yan Zhu 《Bioorganic & medicinal chemistry letters》2010,20(20):6048-6051
Starting from HTS hit 1a, X-ray co-crystallization and molecular modeling were used to design potent and selective inhibitors of PI3-kinase. Bioavailablity in this series was improved through careful modulation of physicochemical properties. Compound 12 displayed in vivo knockdown of PI3K pharmacodynamic markers such as pAKT, pPRAS40, and pS6RP in a PC3 prostate cancer xenograft model. 相似文献
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115.
Susana R Parathath Lori Anne Mainwaring Africa Fernandez-L Cemile G Guldal Zaher Nahle Anna Marie Kenney 《Cell cycle (Georgetown, Tex.)》2010,9(19):4013-4024
Development of the cerebellum, a brain region regulating posture and coordination, occurs post-natally and is marked by rapid proliferation of granule neuron precursors (CGNPs), stimulated by mitogenic Sonic hedgehog (Shh) signaling. β-Arrestin (βArr) proteins play important roles downstream of Smoothened, the Shh signal transducer. However, whether Shh regulates βArrs and what role it plays in Shh-driven CGNP proliferation remains to be determined. Here, we report that Shh induces βArr1 accumulation and localization to the nucleus, where it participates in enhancing expression of the cyclin dependent kinase (cdk) inhibitor p27, whose accumulation eventually drives CGNP cell cycle exit. βArr1 knockdown enhances CGNP proliferation and reduces p27 expression. Thus, Shh-mediated βArr1 induction represents a novel negative feedback loop within the Shh mitogenic pathway, such that ongoing Shh signaling, while required for CGNPs to proliferate, also sets up a cell-intrinsic clock programming their ultimate exit from the cell cycle.Key words: sonic hedgehog, cerebellum, neural precursor, β-arrestin 1, p27, differentiation 相似文献
116.
Polette-Niewold LA Manciu FS Torres B Alvarado M Chianelli RR 《Journal of inorganic biochemistry》2007,101(11-12):1958-1973
Maya Blue is an ancient blue pigment composed of palygorskite clay and indigo. It was used by the ancient Maya and provides a dramatic background for some of the most impressive murals throughout Mesoamerica. Despite exposure to acids, alkalis, and chemical solvents, the color of the Maya Blue pigment remains unaltered. The chemical interaction between palygorskite and indigo form an organic/inorganic complex with the carbonyl oxygen of the indigo bound to a surface Al(3+) in the Si-O lattice. In addition indigo will undergo an oxidation to dehydroindigo during preparation. The dehydro-indigo molecule forms a similar but stronger complex with the Al(3+). Thus, Maya Blue varies in color due to the mixed indigo/dehydroindigo complex. The above conclusions are the result of application of multiple techniques (X-ray diffraction, differential thermal analysis/thermal gravimetric analysis, high resolution transmission electron microscopy, scanning electron microscopy, infrared and Raman spectroscopy) to the characterization of the organic/inorganic complex. A picture of the bonding of the organic molecule to the palygorskite surface forming a surface complex is developed and supported by the results of density functional theory calculations. We also report that other organic molecules such as thioindigo form similar organic/inorganic complexes thus, opening an entirely new class of complex materials for future applications. 相似文献
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118.
Stable isotopes can be used to elucidate ecological relationships in community and trophic studies. Findings are calibrated
against baselines, e.g. from a producer or primary consumer, assumed to act as a reference to the isotopic context created
by spatio-temporal attributes such as geography, climate, nutrient, and energy sources. The ability of an organism to accurately
represent a community base depends on how, and over what time-scale, it assimilates ambient materials. Freshwater mussels
have served as references for trophic studies of freshwater communities and as indicators of change in nutrient pollution
load or source. Their suitability as reference animals has not yet been fully explored, however. We conducted a series of
studies examining the suitability of freshwater mussels as isotopic baselines, using their ability to reflect variation in
ambient nutrient loads as a case scenario. (1) We analyzed bivalve foot tissue δ15N and δ13C from 22 stream reaches in the Piedmont region of North Carolina, USA to show that compositions varied substantially among
locations. Site mean bivalve δ13C values correlated with site ambient particulate organic matter (POM) δ13C values, and site mean bivalve δ15N values correlated with site ambient water dissolved δ15N-NO3 values. (2) Similarity of results among sample types demonstrated that the minimally invasive hemolymph sample is a suitable
substitute for foot tissue in δ15N analyses, and that small sample sizes generate means representative of a larger population. Both findings can help minimize
the impact of sampling on imperiled freshwater mussel populations. (3) In a bivalve transplantation study we showed that hemolymph
δ15N compositions responded to a shift in ambient dissolved δ15N-NO3, although slowly. The tissue turnover time for bivalve hemolymph was 113 days. We conclude that bivalves serve best as biomonitors
of chronic, rather than acute, fluctuations in stream nutrient loads, and provide initial evidence of their suitability as
time-integrated isotopic baselines for community studies. 相似文献
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120.
Olson MM Templeton LJ Suh W Youderian P Sariaslani FS Gatenby AA Van Dyk TK 《Applied microbiology and biotechnology》2007,74(5):1031-1040
Escherichia coli K12 strains producing l-phenylalanine were converted to l-tyrosine-producing strains using a novel genetic method for gene replacement. We deleted a region of the E. coli K12 chromosome including the pheA gene encoding chorismate mutase/prephenate dehydratase, its leader peptide (pheL), and its promoter using a new polymerase chain reaction-based method that does not leave a chromosomal scar. For high level
expression of tyrA, encoding chorismate mutase/prephenate dehydrogenase, its native promoter was replaced with the strong trc promoter. The linked ΔpheLA and Ptrc-tyrA::KanR genetic modifications were moved into l-phenylalanine producing strains by generalized transduction to convert l-phenylalanine-producing strains to l-tyrosine-producing strains. Moreover, introduction of a plasmid carrying genes responsible for sucrose degradation into these
strains enabled l-tyrosine-production from sucrose. 相似文献