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41.
The target antigen for Epstein-Barr virus (EBV)-specific cytotoxic T cells (Tc) was expressed on BJAB cells exposed to the B95-8 strain of EBV for at least one hour. Ultraviolet-light (UV)-irradiated noninfectious B95-8 virus also induced the target antigen on BJAB cells. Cold target competition tests suggested that the target antigen expressed on EBV-infected BJAB cells was distinct from the lymphocyte-detected membrane antigen (LYDMA) which was also recognized by the EBV-specific Tc and expressed on autologous EBV-transformed lymphoblastoid cell line (LCL) cells. Neither of these target antigens for EBV-specific Tc was detected on the surface of EBV-genome positive BJAB cells which had been kept in a long-term culture after EBV-infection. Thus, the virion antigen, especially the EBV-membrane antigen (MA), is a possible candidate for the target antigen expressed on EBV-infected BJAB cells. Lysis of EBV-infected BJAB cells was inhibited by target cell treatment with anti-β2 microglobulin (anti-β2M) antibody and induction of the effector Tc was dependent on the donor individual. These resalts suggested the possibility that the Tc recognizing EBV-infected BJAB cells are restricted by the major histocompatibility complex (MHC). 相似文献
42.
Adults of the grasshopper Atractomorpha lata use a hind leg kick to project their frass a considerable distance from themselves. To clarify the defecation behavior quantitatively and collect basic information that aids in clarification of the adaptive significance of this behavior, we measured the flying distance of kicked frass and examined the factors affecting the flying distance in adult A. lata. Males and females kicked their frass an average of 252 and 487 mm away, respectively. This represented more than ten times the body length or 100 times the length of the frass pellet for either sex. Only sex affected the flying distance of frass. There were sexual differences in hind‐femur length (females longer than males), volume of frass pellet (females larger than males) and ratio of diameter to length of frass pellet (RFP; larger in males than in females). The flying distance appears to be affected by the femur length, volume of frass pellet and RFP when data of both males and females were combined for analysis. However, none of these effects were observed when testing the effects within each sex. These results suggest that the sex difference in the flying distance does not result from the sex difference in femur length, volume of frass pellet or RFP. Because A. lata kicked their frass far away in both sexes, the frass‐kicking behavior might give benefit common to both males and females. 相似文献
43.
KOJI TANAKA 《Biological journal of the Linnean Society. Linnean Society of London》2007,92(2):309-322
The adaptive significance of colour polymorphisms in animals has received extensive scientific attention. In snakes, a generally accepted hypothesis is that melanistic individuals enjoy thermal advantages compared to normal coloured individuals. Elaphe quadrivirgata on Yakushima Island exhibits a distinct melanistic/striped colour dimorphism. To test this hypothesis, the thermal biology of free‐ranging E. quadrivirgata was investigated using temperature‐sensitive radio transmitters. The thermal quality of habitats was also evaluated using physical models of the snake. In addition, the species' set‐point range (Tset) was estimated using a laboratory experiment. In July, thermal environments appear to be benign because snakes were able to maintain their body temperature (Tb) within Tset from the midday to evening by using average thermal habitats. By contrast, later months of the year were severe in thermoregulation, and snakes had difficulty maintaining their Tb within Tset by using average thermal habitats. There were no significant intermorph differences in thermoregulation indices in any months, whereas slight differences were detected in hourly comparisons. Most of these comparisons indicated active and precise thermoregulation (with respect to Tset) in striped individuals by using thermally favourable but rare microhabitats such as forest gap. Thus, the obtained values do not support the prediction that melanistic individuals are precise thermoregulators. Yet, melanistic individuals do modify their thermoregulation strategy with respect to the available thermal environments in contrast to striped individuals. Together with the fact that body heating is slower in striped individuals than in melanistic individuals under experimental conditions, it is concluded that melanistic individuals have the potential to enjoy thermal advantages but that this might be of no practical use in terms of Tb in the wild because of the greater thermoregulatory efforts of striped individuals, and because melanistic individuals may use forest gap rarely due to conspicuousness to visually orientated predators under the exposed habitat. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 92 , 309–322. 相似文献
44.
Five different concentrations (100, 250, 500, 1000 and 2000 μg/L of aflatoxin B1 were found to be inhibitory to seed germination and seedling growth (root and shoot lengths) of mustard seeds (variety Pusa
bold). These also lowered the levels of chlorophyll and carotenoids in the emerging leaves during seedling growth. The inhibitory
effect was correlated with the concentration of applied toxin. 相似文献
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47.
Aberrant frenum attachment would cause plaque accumulation and malalignment of teeth. It can be managed by frenotomy or frenectomy methods, through a conventional surgical technique or laser technique. Therefore, it is of interest to compare frenectomy healing surgical and laser techniques. Data from 51 outpatients and post-operative healing of frenectomy was assessed by Landry’s healing score index using 3 weeks postoperative photographs followed by statistical analysis. Based on the healing score index, the laser technique showed better outcomes than the surgical technique. Moreover, the association between the management of high frenal attachment and the healing score index was found to be statistically significant. 相似文献
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49.
SHIGERU KIKUKAWA RYOU HASHIZUME MIHO HONDA YUKA INOUE TATSUYA MAEKAWA RISA SAKATA NANAKO TAKAHASHI KUNIAKI TANAKA YU UCHIDA 《Physiological Entomology》2013,38(3):253-259
In addition to photoperiod, thermoperiod (or thermocycle) might be an important Zeitgeber for entraining the circadian oscillator controlling adult eclosion rhythm in the Indian meal moth Plodia interpunctella Hübner (Lepidoptera: Pyralidae). This is confirmed by exposing larvae receiving diapause‐preventing treatments to various thermocycles with different means and amplitudes of temperature. The thermocycles investigated in the present study are TC 8 : 16 h, TC 12 : 12 h, TC 16 : 8 h and TC 20 : 4 h, where T and C represent thermophase (30 °C) and cryophase (20 °C), respectively. For all thermocycles, the peak of adult eclosion rhythm occurs at around the mid‐thermophase. This indicates that the larvae use both ‘temperature‐rise’ and ‘temperature‐fall’ signals to adjust the eclosion phase in each thermocycle. The absence (DD) or presence (LL) of light affects this time‐keeping system slightly under the given thermocycle. The rhythmic adult eclosion noted after exposure of larvae to 30 °C DD for 14 days is recorded in the thermocycles (TC 12 : 12 h, DD; mean temperature = 25 °C) with different amplitudes of 27.5/22.5 °C, 26.5/23.5 °C and 25.5/24.5 °C. The peak in adult eclosion advances in time as the amplitude of the temperature cycle decreases. In the temperature cycle of 25.5/24.5 °C, a peak occurs at the end of the cryophase, 2 h before the temperature‐rise. The adult eclosion rhythm is also observed under various thermocycles (TC 12 : 12 h, DD) consisting of different temperature levels (30 to 20 °C) with different amplitudes. It is found that the temporal position of the peak advances significantly when the amplitude of the thermocycle becomes lower. 相似文献
50.
Several cell types migrated cut from small pieces of newt testes cultivated in vitro. Flat fibroblastic cells migrated out within a few days. Then, secondary spermatogonia, identified by the presence of germ cell-specific substances and by the shape and appearance of their nucleus and subcellular organelles, migrated out over the sheet of fibroblastic cells. Sertoli cells co-migrated with secondary spermatogonia, maintaining a similar cellular arrangement to that of testicular cells in vivo. Mitosis of secondary spermatogonia both in clusters and as single cells was frequent from the third day until about 2 weeks after inoculation. During mitosis, active and periodic rotation of chromosomes was observed. Identification of the cell types and studies on their behavior were performed by electron microscopy and phase contrast microscopy. 相似文献