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Conserved function for embryonic nodal cilia 总被引:10,自引:0,他引:10
How left right handedness originates in the body plan of the developing vertebrate embryo is a subject of considerable debate. In mice, a left right bias is thought to arise from a directional extracellular flow (nodal flow) that is generated by dynein-dependent rotation of monocilia on the ventral surface of the embryonic node. Here we show that the existence of node monocilia and the expression of a dynein gene that is implicated in ciliary function are conserved across a wide range of vertebrate classes, indicating that a similar ciliary mechanism may underlie the establishment of handedness in all vertebrates. 相似文献
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Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Insect damage to second-year cones was generally not significantly different between crown levels, but was significantly different among areas and among trees within areas for Conophthorus, Megastigmus, and Cydia. Both cone length and width were not significantly different between lower and middle crown, but cone length was significantly greater in the upper crown. Seeds per cone ranged from 34 to 66, but the percent of sound seed per cone varied significantly according to the amount of insect damage. 相似文献
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Roy Wagner 《Archive for History of Exact Sciences》2010,64(5):485-523
The purpose of this article is to analyse the mathematical practices leading to Rafael Bombelli’s L’algebra (1572). The context for the analysis is the Italian algebra practiced by abbacus masters and Renaissance mathematicians of
the fourteenth to sixteenth centuries. We will focus here on the semiotic aspects of algebraic practices and on the organisation
of knowledge. Our purpose is to show how symbols that stand for underdetermined meanings combine with shifting principles
of organisation to change the character of algebra. 相似文献
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Nègre N Brown CD Ma L Bristow CA Miller SW Wagner U Kheradpour P Eaton ML Loriaux P Sealfon R Li Z Ishii H Spokony RF Chen J Hwang L Cheng C Auburn RP Davis MB Domanus M Shah PK Morrison CA Zieba J Suchy S Senderowicz L Victorsen A Bild NA Grundstad AJ Hanley D MacAlpine DM Mannervik M Venken K Bellen H White R Gerstein M Russell S Grossman RL Ren B Posakony JW Kellis M White KP 《Nature》2011,471(7339):527-531
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DiMaio F Terwilliger TC Read RJ Wlodawer A Oberdorfer G Wagner U Valkov E Alon A Fass D Axelrod HL Das D Vorobiev SM Iwaï H Pokkuluri PR Baker D 《Nature》2011,473(7348):540-543
Molecular replacement procedures, which search for placements of a starting model within the crystallographic unit cell that best account for the measured diffraction amplitudes, followed by automatic chain tracing methods, have allowed the rapid solution of large numbers of protein crystal structures. Despite extensive work, molecular replacement or the subsequent rebuilding usually fail with more divergent starting models based on remote homologues with less than 30% sequence identity. Here we show that this limitation can be substantially reduced by combining algorithms for protein structure modelling with those developed for crystallographic structure determination. An approach integrating Rosetta structure modelling with Autobuild chain tracing yielded high-resolution structures for 8 of 13 X-ray diffraction data sets that could not be solved in the laboratories of expert crystallographers and that remained unsolved after application of an extensive array of alternative approaches. We estimate that the new method should allow rapid structure determination without experimental phase information for over half the cases where current methods fail, given diffraction data sets of better than 3.2?? resolution, four or fewer copies in the asymmetric unit, and the availability of structures of homologous proteins with >20% sequence identity. 相似文献