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191.
ÅSA NORDIN 《Physiologia plantarum》1976,38(4):233-239
The transpiration response to recurrent light periods was studied'n water-stressed wheat seedlings. Seedlings were stressed by three methods: addition of mannitol to the root medium, root cooling and drving of the roots in air. All three methods induced almost equal effects on transpiration regulation during alternating dark and light intervals. Exogenous abscisic acid supplied to the shoots of excised plants had qualitatively the same effect as water stress. Water stress and ABA increased the time lapse between light-on and the onset of transpiration increase and lowered the amplitude of transpiration increase in light. Weak light introduced before strong light shortened the delay times. 相似文献
192.
目的研究运行中的实验动物屏障系统微生物的情况。方法采用沉降菌法、棉拭子法等方法,研究运行中的屏障系统不同区域、不同环境指标下屏障系统内微生物的状况。结果动态下的屏障系统微生物情况与国标GB14925-2001中静态环境有较大不同,动物饲养室和动物实验室沉降菌浓度远高于静态要求;辅助区域在规范化消毒及严格管理的情况下,能达到国标要求。屏障系统的微生物情况存在一定的昼夜变化规律,在晚间出现峰值。结论合适的换气次数可有效控制实验动物屏障系统的沉降菌浓度;加强消毒及硬件的管理,是屏障系统内环境稳定的保障。 相似文献
193.
目的探索长爪沙鼠高胆固醇血症模型建立及辛伐他汀的影响。方法在饲喂长爪沙鼠高脂饲料的同时给予不同浓度辛伐他汀抑制胆固醇生物合成,通过观察肝脏颜色,测量体重、肝重、TC、LDL-C及HDL-C等血脂和肝功能指标判断高脂饲料和辛伐他汀对血脂和肝脏功能的影响。结果动物体重、肝重和肝脏指数没有显著变化。高脂饲料能够促进脂肪在肝脏的沉积,但是对AST和ALT等肝脏功能指标影响不显著;辛伐他汀能够有效抑制TC、LDL-C、HDL-C、TBA和GLU的升高,但对其他指标影响不明显。结论高脂饲料能够快速建立长爪沙鼠高胆固醇血症模型;辛伐他汀能够抑制内源性胆固醇的合成从而有效抑制血浆胆固醇(TC)、LDL-C和HDL-C的升高。结果表明,特殊的反馈调节机制导致长爪沙鼠无法在大量摄入胆固醇时终止内源性胆固醇的合成。长爪沙鼠特殊的反馈调节机制可能是易发高胆固醇血症的一个主要原因。 相似文献
194.
A positive family history of alcohol use disorders (FH) is a robust predictor of personal alcohol abuse and dependence. Exposure to problem-drinking models is one mechanism through which family history influences alcohol-related cognitions and drinking patterns. Similarly, exposure to alcohol advertisements is associated with alcohol involvement and the relationship between affective response to alcohol cues and drinking behavior has not been well established. In addition, the collective contribution that FH, exposure to different types of problem-drinking models (e.g. parents, peers) and personal alcohol use have on appraisal of alcohol-related stimuli has not been evaluated with a large sample. We investigated the independent effects of FH, exposure to problem-drinking models and personal alcohol use on valence ratings of alcohol pictures in a college sample. College students (n = 227) completed measures of personal drinking and substance use, exposure to problem-drinking models, FH and ratings on affective valence of 60 alcohol pictures. Greater exposure to non-familial problem-drinkers predicted greater drinking among college students (beta = 0.17, P < 0.01). However, personal drinking was the only predictor of valence ratings of alcohol pictures (beta = -0.53, P < 0.001). Personal drinking level predicted valence ratings of alcohol cues over and above FH, exposure to problem-drinking models and demographic characteristics. This suggests that positive affective responses to alcohol pictures are more a function of personal experience (i.e. repeated heavy alcohol use) than vicarious learning. 相似文献
195.
The morphology, structure, and optical characteristics of the spicules of some marine glass sponges have been studied. The
results obtained are interpreted from the point of view of their possible role in the vital provision of the sponge organism. 相似文献
196.
Galkina S Deryusheva S Fillon V Vignal A Crooijmans R Groenen M Rodionov A Gaginskaya E 《Genetica》2006,128(1-3):241-251
Giant lampbrush chromosomes, which are characteristic of the diplotene stage of prophase I during avian oogenesis, represent
a very promising system for precise physical gene mapping. We applied 35 chicken BAC and 4 PAC clones to both mitotic metaphase
chromosomes and meiotic lampbrush chromosomes of chicken (Gallus gallus domesticus) and Japanese quail (Coturnix coturnix japonica). Fluorescence in situ hybridization (FISH) mapping on lampbrush chromosomes allowed us to distinguish closely located probes and revealed gene
order more precisely. Our data extended the data earlier obtained using FISH to chicken and quail metaphase chromosomes 1–6
and Z. Extremely low levels of inter- and intra-chromosomal rearrangements in the chicken and Japanese quail were demonstrated
again. Moreover, we did not confirm the presence of a pericentric inversion in Japanese quail chromosome 4 as compared to
chicken chromosome 4. Twelve BAC clones specific for chicken chromosome 4p and 4q showed the same order in quail as in chicken
when FISH was performed on lampbrush chromosomes. The centromeres of chicken and quail chromosomes 4 seem to have formed independently
after centric fusion of ancestral chromosome 4 and a microchromosome. 相似文献
197.
The periodic occurrence of chiasmata was studied in lampbrush chromosomes of the chicken (Gallus gallus domesticus). It was shown that the most probable interference distance in chicken macrobivalents 1-3 corresponded to 24.48 Mb. The distance at which absolute interference is observed in chicken macrochromosomes varies from 5.75 to 9.02 Mb. 相似文献
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