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排序方式: 共有488条查询结果,搜索用时 15 毫秒
71.
L. Panizzi Maria Luisa Scarpati Giovanna Oriente 《Cellular and molecular life sciences : CMLS》1955,11(10):383-384
Summary Quinic acid methyl ester, having the 1.4 and 5 hydroxy-groups suitably blocked, was condensed with the carbonilcaffeic acid chloride.Gradual hydrolysis of the condensation compound gave place to chlorogenic acid. 相似文献
72.
Maria Assunta Mor 《Cellular and molecular life sciences : CMLS》1956,12(6):224-226
Riassunto L'Autore ha studiato l'influenza della concentrazione degli ioni Ca++ e Mg++ sull'ATPasi degli atri e dei ventricoli di cuore di cavia. Tale attività è maggiore a pH 9,2 che a pH 6,8. Mentre il Ca++ influisce differenziando decisamente le attività degli atri da quelle dei ventricoli, il Mg++ accentua piuttosto una differenza tra la parte destra e la sinistra. Il calore distrugge quasi completamente l'attività enzimatica dopo una permanenza a 60° per 20 min. 相似文献
73.
Hillier LW Graves TA Fulton RS Fulton LA Pepin KH Minx P Wagner-McPherson C Layman D Wylie K Sekhon M Becker MC Fewell GA Delehaunty KD Miner TL Nash WE Kremitzki C Oddy L Du H Sun H Bradshaw-Cordum H Ali J Carter J Cordes M Harris A Isak A van Brunt A Nguyen C Du F Courtney L Kalicki J Ozersky P Abbott S Armstrong J Belter EA Caruso L Cedroni M Cotton M Davidson T Desai A Elliott G Erb T Fronick C Gaige T Haakenson W Haglund K Holmes A Harkins R Kim K Kruchowski SS Strong CM Grewal N Goyea E 《Nature》2005,434(7034):724-731
Human chromosome 2 is unique to the human lineage in being the product of a head-to-head fusion of two intermediate-sized ancestral chromosomes. Chromosome 4 has received attention primarily related to the search for the Huntington's disease gene, but also for genes associated with Wolf-Hirschhorn syndrome, polycystic kidney disease and a form of muscular dystrophy. Here we present approximately 237 million base pairs of sequence for chromosome 2, and 186 million base pairs for chromosome 4, representing more than 99.6% of their euchromatic sequences. Our initial analyses have identified 1,346 protein-coding genes and 1,239 pseudogenes on chromosome 2, and 796 protein-coding genes and 778 pseudogenes on chromosome 4. Extensive analyses confirm the underlying construction of the sequence, and expand our understanding of the structure and evolution of mammalian chromosomes, including gene deserts, segmental duplications and highly variant regions. 相似文献
74.
The faithful inheritance of genetic information, which is essential for all organisms, requires accurate DNA partition (segregation) at cell division. In prokaryotes, partition is mediated by par systems, for which the P1 plasmid system of Escherichia coli is a prototype comprising a partition site and two proteins, ParA and ParB. To form the partition complex necessary for segregation, P1 ParB must recognize a complicated arrangement of A-box and B-box DNA motifs located on opposite ends of a sharply bent parS partition site of approximately 74 bp (refs 3-7). Here we describe structures of ParB bound to partition sites. ParB forms an asymmetric dimer with extended amino-terminal HTH (helix-turn-helix) domains that contact A-boxes. The two HTH domains emanate from a dimerized DNA-binding module composed of a six-stranded beta-sheet coiled-coil that binds B-boxes. Strikingly, these individual DNA-binding modules rotate freely about a flexible linker, enabling them to contact several arrangements of A- and B-boxes. Most notably, each DNA-binding element binds to and thus bridges adjacent DNA duplexes. These unique structural features of ParB explain how this protein can bind complex arrays of A- and B-box elements on adjacent DNA arms of the looped partition site. 相似文献
75.
A. Pessina Maria Grazia Neri A. Muschiato 《Cellular and molecular life sciences : CMLS》1982,38(9):1056-1057
Summary Filtrates fromE. coli H10407 cultures, giving a positive response for heat-labile enterotoxin (LT) in the Y-1 cell test, show an inhibitory activity both on3H-thymidine uptake by Ehrlich ascites cells and on granulocytic-macrophagic precursors (CFU-C) in murine bone marrow.Acknowledgments. We gratefully acknowledge the expert technical assistance of L. Basso and A. Gerosa of Department of Pathology, Hospital of Desio. 相似文献
76.
L. Mazzanti M. Lopez Maria Grazia Berti 《Cellular and molecular life sciences : CMLS》1964,20(9):492-493
Riassunto Gli autori descrivono le lesioni del testicolo del ratto osservate nel corso di sperimentazioni con la fluoroacetamide. Tali lesioni consistono in alterazioni regressive interessanti elettivamente la linea seminale. 相似文献
77.
C. M. Caldarera C. Cozzani Maria S. Moruzzi 《Cellular and molecular life sciences : CMLS》1966,22(9):579-580
Riassunto Un considerevole aumento di spermina e spermidina è stato osservato nel fegato di ratti dopo 48 h dalla pan-irradiazione con dosi totali di raggi X di 800 e di 1000 r. Gli acidi ribonucleici si modificano nello stesso modo, quantunque in misura minore. 相似文献
78.
Peroxiredoxins are conserved markers of circadian rhythms 总被引:1,自引:0,他引:1
79.
Zuber MT Head JW Smith DE Neumann GA Mazarico E Torrence MH Aharonson O Tye AR Fassett CI Rosenburg MA Melosh HJ 《Nature》2012,486(7403):378-381
Shackleton crater is nearly coincident with the Moon's south pole. Its interior receives almost no direct sunlight and is a perennial cold trap, making Shackleton a promising candidate location in which to seek sequestered volatiles. However, previous orbital and Earth-based radar mapping and orbital optical imaging have yielded conflicting interpretations about the existence of volatiles. Here we present observations from the Lunar Orbiter Laser Altimeter on board the Lunar Reconnaissance Orbiter, revealing Shackleton to be an ancient, unusually well-preserved simple crater whose interior walls are fresher than its floor and rim. Shackleton floor deposits are nearly the same age as the rim, suggesting that little floor deposition has occurred since the crater formed more than three billion years ago. At a wavelength of 1,064 nanometres, the floor of Shackleton is brighter than the surrounding terrain and the interiors of nearby craters, but not as bright as the interior walls. The combined observations are explicable primarily by downslope movement of regolith on the walls exposing fresher underlying material. The relatively brighter crater floor is most simply explained by decreased space weathering due to shadowing, but a one-micrometre-thick layer containing about 20 per cent surficial ice is an alternative possibility. 相似文献
80.
Tsukada Y Fang J Erdjument-Bromage H Warren ME Borchers CH Tempst P Zhang Y 《Nature》2006,439(7078):811-816