全文获取类型
收费全文 | 576篇 |
免费 | 43篇 |
出版年
2023年 | 4篇 |
2021年 | 11篇 |
2020年 | 7篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 13篇 |
2016年 | 10篇 |
2015年 | 14篇 |
2014年 | 32篇 |
2013年 | 19篇 |
2012年 | 27篇 |
2011年 | 30篇 |
2010年 | 19篇 |
2009年 | 14篇 |
2008年 | 27篇 |
2007年 | 37篇 |
2006年 | 16篇 |
2005年 | 22篇 |
2004年 | 26篇 |
2003年 | 24篇 |
2002年 | 25篇 |
2001年 | 18篇 |
2000年 | 16篇 |
1999年 | 21篇 |
1998年 | 9篇 |
1997年 | 5篇 |
1995年 | 10篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 19篇 |
1987年 | 11篇 |
1986年 | 8篇 |
1985年 | 9篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1970年 | 8篇 |
1969年 | 4篇 |
1967年 | 4篇 |
排序方式: 共有619条查询结果,搜索用时 31 毫秒
611.
Yukiko Yonemori Shogo Kokubu Gregory N. Nishihara Hikaru Endo Ryuta Terada 《Phycological Research》2023,71(1):3-12
The responses of photochemical efficiency to desiccation and salinity gradients in an intertidal edible brown macroalga, Sargassum fusiforme (Harvey) Setchell (Sargassaceae, Fucales), were determined using a pulse amplitude modulation (PAM)-chlorophyll fluorometer. The effective quantum yields (ΔF/Fm'; = ΦPSII) of photosystem II (PSII) dropped to zero after 360-min aerial exposure under low irradiance (20 μmol photons m−2 s−1) and 120-min exposure under high irradiance (700 μmol photons m−2 s−1) for this species at 20°C and 50% relative humidity. Under these conditions, ΔF/Fm' failed to recover to initial levels even after 1-day rehydration in seawater. In general, ΔF/Fm' decreased as desiccation reduced the absolute water content (AWC, %). Nevertheless, when AWC was above ca. 20%, ΔF/Fm' was mostly restored to initial levels after 1-day rehydration in seawater, suggesting strong tolerance to dehydration. Furthermore, S. fusiforme appeared to tolerate a broad range of salinity (i.e. 15–50 psu) during six days of culture; however, ΔF/Fm' declined when salinity was <10 and 60 psu. Strong tolerance to dehydration and salinity stress likely provides S. fusiforme an advantage that allows it to flourish in the intertidal habitat. 相似文献
612.
Yasuhiro Kajihara Yurie Kanemitsu Mika Nishihara Ryo Okamoto Masayuki Izumi 《Journal of peptide science》2014,20(12):958-963
In order to synthesize interferon‐γ glycoform having an oligosaccharide at the 97 position by a semi‐synthetic method, interferon‐γ‐polypeptide‐(1–94)‐α‐hydrazide was prepared by the specific Cys‐cyanylation of polypeptide‐(1–94)‐Cys‐His6 expressed from E. coli and subsequent hydrazinolysis in 22% yield (two steps). This polypeptide‐α‐hydrazide was then converted into corresponding polypeptide‐α‐thioester under NaNO2/acid conditions followed by thiolysis in 83% yield. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
613.
Kahoko Tochigi Kato Shuri Satoshi Kikuchi Shoji Naoe Shinsuke Koike Teruyoshi Nagamitsu 《Plant Species Biology》2021,36(2):230-245
Hybrid zones between species with staggered reproductive phenology sometimes occur along elevational gradients. The maintenance of such hybrid zones may depend on elevational shift in phenology and vertical dispersal of pollen and seeds. In a hybrid zone of Cerasus leveilleana (Cl) and C. sargentii (Cs), 111 adults, 372 embryos of 65 mothers, and 133 juveniles were sampled across elevations of 900–1,400 m in central Japan. Using the hybrid index estimated from nuclear microsatellites, the samples were assigned to Cl, Cs or their hybrid taxon. Cs was in higher elevations than Cl with an overlapping range, and their hybrids were in intermediary elevations. Flowering periods were earlier in Cs than in Cl with little overlap at the same elevation and were intermediate in their hybrids. Flowering periods were delayed in higher elevations and overlapped between Cl and Cs in different elevations. Fruiting periods were slightly earlier in Cs than in Cl but were largely overlapped. Effective pollinators and seed dispersers were common among the taxa. Changes in the hybrid index from mothers to their embryos were larger in hybrid mothers than in Cl or Cs mothers, indicating mating of hybrids with diverse taxa. In Cs, juveniles were more abundant in lower elevations than embryos, indicating downhill seed dispersal. Proportions of hybrids were 19% in embryos, 17% in juveniles and 12% in adults. The findings suggest that the hybrid zone is maintained by interspecific pollination between different elevations, backcrossing with hybrids at similar elevations, vertical seed dispersal and mild selection against hybrids. 相似文献
614.
When the spores of Bacillus megaterium QM B1551 (ATCC 12872) were incubated with 5 mM CdCl2 at 30 C, they underwent the early germination events, such as loss of heat resistance and release of calcium dipicolinate, in the same way as when they were germinated by glucose + KNO3. However, germination by CdCl2 caused no increase in the reducing groups in the cortex and no excretion of glucosamine-containing materials due to the hydrolysis of the cortex peptidoglycan. Addition of CdCl2 at any time during germination by glucose + KNO3 inhibited the release of glucosamine-containing materials from the spores, whereas removal of cadmium from the CdCl2-germinated spores by treatment with cysteine restored the hydrolysis of peptidoglycan. These results suggested that CdCl2 caused the early events of spore germination but prevented the spores from undergoing the events following germination by inhibiting the enzymatic lysis of the cortex peptidoglycan. The conclusion from the study is that cortex degradation is not always required for the initiation of germination. 相似文献
615.
T. Nishihara T. Yamada K. Takano S. Osada J. Nishikawa M. Imagawa 《Letters in applied microbiology》1994,19(4):181-183
A shaken thermal gradient device providing temperatures between 8.3 and 33.5° C was used to investigate the effects of silver ion on the duration of the lag phase and on minimum apparent growth temperatures of Hyphomicrobium spp. grown at 29 and 9°C. With 29°C-grown inocula, at lower temperatures, an increased time was required for growth initiation in the presence of silver ion added at 5 ng ml-1 . With silver ion added at 10 or 100 ng ml-1 , growth initiation was not observed at lower temperatures. With 100 ng ml-1 added silver ion, this effect also was observed with 9°C-grown inocula. This increased sensitivity to silver ion could limit the ability of Hyphomicrobium spp., and possibly other microbes, to initiate growth and to contribute to microbial functioning in silver-impacted low temperature environments. 相似文献
616.
617.
Mice either excreting or not excreting Pseudomonas aeruginosa in feces were maintained in stainless steel mesh cages on an automated rearing apparatus with automatic water-supply nozzles and intermittently flusing metal racks. No evidence of transmission of the organisms from positive mice to negative ones was obtained during at least eight weeks. 相似文献
618.
Using immunological techniques, we studied the behavior of spore coat protein during sporulation of Bacillus megaterium ATCC 19213. Antibody specific to the main coat protein of 17,000 daltons was prepared and used to demonstrate that the spore coat protein was synthesized and deposited at a later stage during sporulation. 相似文献
619.