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Immobilized a-chymotrypsin was used as catalyst for studying temperature effects on acyl transfer reactions (acyl-donor: Bz-TyrOEt) in a water-immiscible organic solvent. The solubility of the two nucleophiles, Phe-NH and water, decreased with decreasing temperature. The relative decrease for the amide was larger (2.4-fold) than for water. Therefore the thermodynamic activity (estimated by the relative saturation) increased more for this substrate and hence the selectivity in the reaction was increased. 相似文献
4.
Johan D. Vochteloo Paul J. A. Timmermans Jo M. H. Vossen John A. H. Diujghuisen 《International journal of primatology》1995,16(3):277-293
Most surrogate-reared long-tailed macaques persistently avoid a big novel object, whereas most mother-reared subjects approach
it. A striking difference between these attachment figures is that the mothers moved about with their infants, whereas the
surrogates were fixed to the wall In this experiment, we aimed to find out whether mobility of the attachment figure plays
a part in the development of an infant’s responses to big novel objects. We studied the effects of mobility of the attachment
figure by restraining mothers in their range of action. We confined mothers of the experimental group in a small part of the
home cage. Their infants could leave the cage in which their mothers were restrained. Infants that were growing up with unrestrained
mothers made up the control group. At two different ages all infants encountered a big novel object. We used two different
objects. We found that the range of action of the mother did not significantly affect the responses of infants to big novel
objects. As in the previous studies, most of the mother-reared monkeys approached the objects. The age at which an infant
was first exposed to an object did not significantly affect its behavior toward it. Further, the two different objects evoked
the same reactions. 相似文献
5.
Potamotrygon marquesi, sp. nov., is described and compared with other species of Potamotrygon occurring in the Amazon Basin. The identity of this new species is supported by an extensive external and internal morphological study including coloration pattern, squamation, skeleton and ventral lateral-line canals. Morphometrics and meristics were used to further distinguish P. marquesi from congeners. Potamotrygon marquesi was first considered to fall within the range of variation found in P. motoro. However, even with an extensive variation in coloration observed in P. motoro, this new species presents a series of autapomorphies that confidently distinguishes it from what is understood as the morphological variation found in P. motoro. Additional morphological characters that diagnose P. marquesi include three angular cartilages, asymmetrical star-shaped denticles, a single regular row of spines on tail dorsum, lateral row of caudal spines near the sting insertion, dorsal disc background in beige and grey mixed with shades of grey and bearing open and closed bicolored rings, among others. Although presenting a gap of distribution along the west–east extension of the Amazon Basin, its diagnostic charactistics are consistent in both recorded regions. Our study supports the need for many morphological characters to robustly distinguish members of Potamotrygoninae considering their extremely variable dorsal disc color pattern. 相似文献
6.
Jun Seong Jeong Min Jee Kim Jeong Sun Park Keon Hee Lee Yong Hun Jo Jun-ichi Takahashi Yong Soo Choi Iksoo Kim 《Journal of Asia》2021,24(2):135-147
The yellow-legged hornet, Vespa velutina nigrithorax (Hymenoptera: Vespidae), invaded South Korea in 2003 through Busan metropolitan city, which is located in the southeast region of the country. Previous studies aiming to trace the origin of V. velutina in Korea used a portion of mitochondrial (mt) COI and detected a single haplotype common to the site of origin. However, no subsequent study on invasive dynamics such as additional entry and/or another site of entry has been performed. In this study, segments of mt COI, CytB, and lrRNA were sequenced from 238 individuals collected in 11 Korean and two Japanese localities, but no variation in each gene was observed. Thus, we developed two intergenic spacer (IGS) sequences from the publicly available mt genome of V. velutina, which provided substantially increased variability (i.e., 19 haplotypes with 1.74% maximum sequence divergence in 1,129–1,146-bp-long concatenated sequences). Population genetic analyses using the concatenated sequences unexpectedly provided higher genetic diversity estimates in the northwest and southwest regions, both of which also harbor international cargo ports, than in the southeast region, in which Busan is located. Furthermore, this genetic result was roughly concordant with our questionnaire survey demonstrating that V. velutina was observed in apiaries located in the northwest and southwest regions up to 2012, when there was no reported prevalent distribution of the hornet beyond the southeast region. These results collectively suggest that the northwest and southwest regions of Korea are additional sites of V. velutina entry to the country, independent from the southeast region origin. 相似文献
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Dong Hyun Jo Chang Sik Cho Jin Hyoung Kim Hyoung Oh Jun Jeong Hun Kim 《Journal of biomedical science》2013,20(1):38
Effective and validated animal models are valuable to investigate the pathogenesis and potential therapeutics for human diseases. There is much concern for diabetic retinopathy (DR) in that it affects substantial number of working population all around the world, resulting in visual deterioration and social deprivation. In this review, we discuss animal models of DR based on different species of animals from zebrafish to monkeys and prerequisites for animal models. Despite criticisms on imprudent use of laboratory animals, we hope that animal models of DR will be appropriately utilized to deepen our understanding on the pathogenesis of DR and to support our struggle to find novel therapeutics against catastrophic visual loss from DR. 相似文献
8.
Maria de Lourdes Lucio Ferrarese Osvaldo Ferrarese-Filho JoĂo Domingos Rodrigues 《Acta Physiologiae Plantarum》2000,22(2):121-124
Ferulic acid uptake by soybean root in nutrient culture was investigated by the depletion method at different concentrations,
temperatures and pH. Results showed that soybean roots absorbed this compound at greater rates in the concentrations between
0.05-mM and 1.0-mM and it was concentration dependent. Ferulic acid uptake was unaffected at pH 4.5 or 6.0 but reduced at
pH 7.0. At pH 6.0, uptake rates decreased significantly with increasing temperature of nutrient solution. 相似文献
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A new method for preparation of sections of undecalcified bone is described. Samples of ovine bone were embedded in methylmethacrylate and thick-sectioned with a cutoff machine or commercial band saw. Composite slides were prepared by gluing white acrylic to glass using cyanoacrylate glue. Bone sections were glued to the composite slide and then surface polished by grinding or ultramilling. The polished surface of the section was then etched and stained. The techniques described in this paper reduce the time spent grinding or milling sections and improve resolution of surface-stained features of undecalcified bone sections. 相似文献