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91.
Kazuho Fujine Ryuji Tada Masanobu Yamamoto 《Palaeogeography, Palaeoclimatology, Palaeoecology》2009,280(3-4):350-360
Paleo-sea-surface temperatures in the northeastern- and southeastern-parts of the Japan Sea were reconstructed for the last 160 kyr using alkenone temperatures (UK′37-temperatures). UK′37-temperatures at two sites show distinct glacial–interglacial changes during the last 160 kyr except for the interval corresponding to middle MIS 3 to MIS 2. On orbital-timescales, UK′37-temperature tends to be high during MIS 5e, MIS 5c, and MIS 5a, which coincides with the intervals of stronger East Asian summer monsoon activity. The amplitude of temperature fluctuations in the Japan Sea is significantly higher than those in the neighboring seas. We suggest that the SST variation was amplified by the increasing source water (Kuroshio water) temperature and the changes in the volume transport of the Tsushima Warm Current (TWC) and/or the north–south oscillation of the sub-polar front position within the Japan Sea. Millennial-scale temperature fluctuations in the Japan Sea show that the temperature at the northern site was higher than that at the southern site during warmer periods of MIS 5, which is called “temperature reversal.” By analogy with modern oceanography, the temperature reversal could reflect the enhanced volume transport of the TWC and the spatial relationship between the studied site and the branches of the TWC, which is an essential factor in north–south temperature reversal around the eastern Japan Sea. Temperature drops were found at 114 ka, 111 ka, 93 ka, 87 ka, and 77 ka in MIS 5. Those events were associated with an increase in organic carbon and alkenone contents and can be correlated with the abundance peaks of ice-rafted debris (IRD) at Site GH05-1208 in the northern Japan Sea, suggesting that the surface water was cooled by enhanced mixing and consequent upwelling in a stronger winter monsoon regime. 相似文献
92.
Ryuji Yonekura Hiroki Yamanaka Atushi Ushimaru Kazuaki Matsui Kimiko Uchii Atsushi Maruyama 《Biological invasions》2009,11(6):1347-1355
Asymmetry in the competition abilities between invasive and native consumers can potentially influence the colonization success
by invasive species. We tested whether a subsidy of allochthonous prey enhanced an asymmetric competition between invasive
bluegill (Lepomis macrochirus) and two native cyprinid fish, that is, stone moroko (Pseudorasbora parva) and tamoroko (Gnathopogon elongatus elongatus). A field experiment was conducted using enclosures wherein the strength of interspecific competition and the presence/absence
of allochthonous prey were manipulated. The experiment revealed that allochthonous prey alleviated the limitation of fish
growths caused by a severe competition for aquatic prey resources. However, the importance of allochthonous prey differed
considerably between invasive bluegill and the two native cyprinids. Individual bluegills grew faster when the allochthonous
prey was supplied, whereas no difference in growth was observed in the two cyprinids whether or not allochthonous prey was
supplied. Interestingly, the importance of allochthonous prey on the total amount of bluegill growth varied depending on the
numerical abundance of native cyprinid competitors, and this importance increased when the native cyprinids were abundant.
These findings indicated that allochthonous prey provides an asymmetric growth benefit to invasive bluegills over the two
native cyprinids by alleviating asymmetrically the competition strength in a Japanese pond, especially under the conditions
of severe interspecific resource competition and a limitation in the utilization of in situ prey resources. 相似文献
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96.
Kita S Hashiba R Ueki S Kimoto Y Abe Y Gotoda Y Suzuki R Uraki E Nara N Kanazawa A Hatakeyama D Kawai R Fujito Y Lukowiak K Ito E 《The Biological bulletin》2011,220(1):71-81
In conditioned taste aversion (CTA) training performed on the pond snail Lymnaea stagnalis, a stimulus (the conditional stimulus, CS; e.g., sucrose) that elicits a feeding response is paired with an aversive stimulus (the unconditional stimulus, US) that elicits the whole-body withdrawal response and inhibits feeding. After CTA training and memory formation, the CS no longer elicits feeding. We hypothesize that one reason for this result is that after CTA training the CS now elicits a fear response. Consistent with this hypothesis, we predict the CS will cause (1) the heart to skip a beat and (2) a significant change in the heart rate. Such changes are seen in mammalian preparations exposed to fearful stimuli. We found that in snails exhibiting long-term memory for one-trial CTA (i.e., good learners) the CS significantly increased the probability of a skipped heartbeat, but did not significantly change the heart rate. The probability of a skipped heartbeat was unaltered in control snails given backward conditioning (US followed by CS) or in snails that did not acquire associative learning (i.e., poor learners) after the one-trial CTA training. These results suggest that as a consequence of acquiring CTA, the CS evokes conditioned fear in the conditioned snails, as evidenced by a change in the nervous system control of cardiac activity. 相似文献
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98.
Kitaura K Fujii Y Hayasaka D Matsutani T Shirai K Nagata N Lim CK Suzuki S Takasaki T Suzuki R Kurane I 《Journal of immunology (Baltimore, Md. : 1950)》2011,187(8):3919-3930
It has been reported that brain-infiltrating T lymphocytes play critical roles in the clearance of West Nile virus (WNV) from the brains of mice. We characterized brain-infiltrating T lymphocytes by analyzing the TCR α- and β-chain repertoires, T cell clonality, and CDR3 sequences. CD3(+)CD8(+) T cells were localized in the WNV-infected brains. The expression of CD3, CD8, CD25, CD69, perforin, and granzymes positively correlated with viral RNA levels, and high levels of expression of IFN-γ, TNF-α, and IL-2 were detected in the brains, suggesting that Th1-like cytotoxic CD8(+) T cells are expanded in the brains in response to WNV infection. The brain-infiltrating T lymphocytes dominantly used TCR genes, VA1-1, VA2-1, VB5-2, and VB8-2, and exhibited a highly oligoclonal TCR repertoire. Interestingly, the brain-infiltrating T lymphocytes had different patterns of TCR repertoire usages among WNV-, Japanese encephalitis virus-, and tick-borne encephalitis virus-infected mice. Moreover, CD8(+) T cells isolated from the brains of WNV-infected mice produced IFN-γ and TNF-α after in vitro stimulation with peritoneal cells infected with WNV, but not with Japanese encephalitis virus. The results suggest that the infiltrating CD8(+) T cells were WNV-specific, but not cross-reactive among flaviviruses. T cells from the WNV-infected brains exhibited identical or similar CDR3 sequences in TCRα among tested mice, but somewhat diverse sequences in TCRβ. The results indicate that WNV-specific CD3(+)CD8(+) T cells expanding in the infected brains are highly oligoclonal, and they suggest that TCR α-chains play a dominant and critical role in Ag specificity of WNV-specific T cells. 相似文献
99.
Takao Ishii Eri Hashimoto Wataru Ukai Yohei Kakutani Ryuji Sasaki Toshikazu Saito 《PloS one》2014,9(5)
Recent reports suggest a lifetime suicide risk for schizophrenia patients of approximately 5%. This figure is significantly higher than the general population suicide risk consequently, detection of those at risk is clinically important. This study was undertaken to define the characteristics of suicide attempts by schizophrenia patients compared with attempts by patients with mood disorders. All patients were diagnosed using the ICD-10 criteria. The study population comprised 65 patients with F2 disorders (schizophrenia, schizotypal and delusional disorders), i.e., “the F2 group”, and 94 patients with F3 disorders (mood disorders), i.e., “the F3 group”, who presented in the clinical setting of consultation-liaison psychiatry. The F2 group had a significantly younger mean age and significantly higher ratios of ‘past/present psychiatric treatment’ and ‘more than 3 months interruption of psychiatric treatment’. In contrast, the ratios of ‘physical disorder comorbidity’, ‘alcohol intake at suicide attempt’ and ‘suicide note left behind’ were significantly higher in the F3 group. The F2 group attempted suicide by significantly more serious methods. Furthermore, ‘hallucination-delusion’ was the most prevalent motive in the F2 group and was the only factor that showed a significant association with the seriousness of the method of suicide attempt (OR = 3.36, 95% CI: 1.05–11.33). 相似文献
100.
Satoshi Nozuma Eiji Matsuura Toshio Matsuzaki Osamu Watanabe Ryuji Kubota Shuji Izumo Hiroshi Takashima 《PloS one》2014,9(5)