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81.
The leaf-mining larvae of the celery fly, P. heraclei, have the ability to leave their primary mine to bore a secondary mine in another leaflet or leaf. This phenomenon is always numerically significant under natural conditions (depending on the plots and the years, 38 to 97% of the larvae observed made such a change), although it is not an obligatory behavior. The distribution of the secondary mines on the leaflets and on the leaves varies with the importance of the migrations, with the total unoccupied and healthy leaf area and with the relative position of different leaves on the plant. These migrations are due to the insufficiency of healthy food available for the larvae: either because the quantity of parenchyma offered by a leaflet is too small for a larva, or because there is intraspecific competition following multiple egg-layings on the same leaflet, or because there is a deterioration of the quality of the parenchyma, particularly following the development of celery leaf-spot. The possibility for the larvae of P. heraclei to bore secondary mines appears to be an extremely important factor in the population dynamics of this species. This permits the reduction of the negative effects of intraspecific competition and celery leaf-spot, and permits the colonization by the larvae of young leaves not used by the females at the time of egg-laying.  相似文献   
82.
Carrion represents an unpredictable and widely distributed primary food source for vultures and other avian scavengers. Avian scavengers in African savanna ecosystems are reported to rely exclusively on visual stimuli to locate carcasses. However, carnivores’ predation of large mammalian herbivores and subsequent competition for access to the carcass can result in considerable noise, often audible over long distances and for prolonged periods. Vultures and other avian scavengers may therefore detect and respond to these auditory cues, as do the mammalian carnivores alongside which vultures have coevolved, but this has not been investigated to date. Working in the Serengeti ecosystem, Tanzania, we used diurnal auditory broadcasts to simulate predation and competitive carnivore feeding interactions. Based on the current understanding of avian scavenger ecology, we hypothesized that avian responses to call‐in stations would be evoked exclusively by visual, rather than auditory, cues. We therefore predicted that (a) the arrival of avian scavengers at call‐in stations should be preceded and facilitated by mammalian carnivores and that (b) the arrival of avian scavengers would be positively correlated with the number of mammalian scavengers present, which would increase detectability. We recorded 482 birds during 122 separate playback events. In 22% of these instances, avian scavengers arrived first, ruling out responses based exclusively on visual observations of mammalian carnivores, thereby contradicting our first prediction. Furthermore, the first avian arrivals at survey sessions were inversely related to the number of hyenas and jackals present, contradicting our second prediction. Since no bait or carcasses were used during the experiments, these responses are indicative of the birds’ ability to detect and respond to audio stimuli. Our findings challenge the current consensus of sensory perception and foraging in these species and provide evidence that avian scavengers have the ability to use sound to locate food resources.  相似文献   
83.
84.
Sex change in teleost fishes is commonly regulated by social factors. In species that exhibit protogynous sex change, such as the orange-spotted grouper Epinephelus coioides, when the dominant males are removed from the social group, the most dominant female initiates sex change. The aim of this study was to determine the regulatory mechanisms of socially controlled sex change in E. coioides. We investigated the seasonal variation in social behaviours and sex change throughout the reproductive cycle of E. coioides, and defined the behaviour pattern of this fish during the establishment of a dominance hierarchy. The social behaviours and sex change in this fish were affected by season, and only occurred during the prebreeding season and breeding season. Therefore, a series of sensory isolation experiments was conducted during the breeding season to determine the role of physical, visual and olfactory cues in mediating socially controlled sex change. The results demonstrated that physical interactions between individuals in the social groups were crucial for the initiation and completion of sex change, whereas visual and olfactory cues alone were insufficient in stimulating sex change in dominant females. In addition, we propose that the steroid hormones 11-ketotestosterone and cortisol are involved in regulating the initiation of socially controlled sex change.  相似文献   
85.
The early-phase migration dynamics of Echinococcus multilocularis in the intermediate hosts remain largely unknown. We compared the parasite burden in the intestine, liver and faeces of DBA/2 and C57BL/6 mouse strains using parasite-specific quantitative PCR. Our results indicated that the parasites invaded mainly from the middle segments of the small intestine and completed migration to the liver within 24 h p.i. C57BL/6 mice had lower parasite DNA burdens in the intestine and liver but higher in the faeces than DBA/2 mice, suggesting that parasite invasion of the intestine may be a critical stage regulating susceptibility to E. multilocularis infection in mice.  相似文献   
86.
摘要 目的:探讨原发性醛固酮增多症(primary aldosteronism,PA)大鼠其自主活动和对学习记忆行为的影响。方法:8周龄健康雄SD(Sprague-Dawley)大鼠(n=30)随机分为对照组与模型组各15只。两组都皮下埋置微量渗透泵,模型组泵内灌注醛固酮,对照组泵内灌注等量的生理盐水,记录大鼠自主活动和学习记忆行为的变化情况。结果:所有大鼠均存活,模型组都造模成功,切口愈合良好。模型组造模后的收缩压高于对照组(P<0.05),也高于造模前(P<0.05),两组造模前后心率对比差异无统计学意义(P>0.05)。模型组造模后的逃避潜伏期与穿台次数少于对照组(P<0.05),也少于造模前(P<0.05)。模型组造模后的自主活动次数高于对照组(P<0.05),也高于造模前(P<0.05)。造模后模型组的鼠双微基因2(Mouse Double Microgene 2,MDM2)蛋白相对表达水平高于对照组(P<0.05)。造模后模型组的血清醛固酮含量都高对照组(P<0.05),血清钾离子、钠离子、肾素活性低于对照组(P<0.05)。结论:原发性醛固酮增多症大鼠伴随有血清钾离子、钠离子含量降低与MDM2蛋白的高表达,从而导致大鼠出现自主活动和学习记忆行为障碍。  相似文献   
87.
摘要 目的:分析熊去氧胆酸联合非诺贝特对原发性胆汁性胆管炎无熊去氧胆酸生化反应的临床疗效及安全性。方法:151例原发性胆汁性胆管炎无熊去氧胆酸患者按随机数表法分为73例对照组和78例研究组。对照组在常规治疗基础上给予安慰剂联合熊去氧胆酸治疗,研究组在常规基础上给予非诺贝特联合熊去氧胆酸治疗,两组均持续治疗12个月。比较两组临床疗效,肝功能,血脂指标,肝纤维化指标,免疫球蛋白G(IgG)、免疫球蛋白M(IgM),瘙痒及乏力评分,不良反应发生情况。结果:治疗后,研究组总有效率高于对照组,比较差异有统计学意义(P<0.05)。治疗后,两组肝功能指标均降低,研究组低于对照组,比较有统计学意义(P<0.05)。治疗后,两组总胆固醇(TC)、甘油三酯(TG)均降低,研究组低于对照组,比较有统计学意义(P<0.05),两组治疗前后低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)比较无统计学意义(P>0.05)。治疗后,两组肝纤维化指标均降低,研究组低于对照组,比较有统计学意义(P<0.05)。治疗后,两组IgG、IgM均降低,研究组低于对照组,比较有统计学意义(P<0.05)。治疗后,两组瘙痒、乏力评分均降低,研究组低于对照组,比较有统计学意义(P<0.05)。两组不良反应发生率比较差异无统计学意义(P>0.05)。结论:熊去氧胆酸联合非诺贝特对原发性胆汁性胆管炎无熊去氧胆酸生化反应的疗效较好,能够改善肝功能,且未明显增加药物不良反应。  相似文献   
88.
目的:探讨微血管减压术(MVD)联合感觉根部分切断术(PSR)对原发性三叉神经痛(TN)患者疼痛评分、生活质量及睡眠状况的影响。方法:回顾性分析2015年2月~2019年3月期间我院收治的80例原发性TN患者的临床资料,根据手术方式的不同将患者分为对照组(n=40,MVD治疗)和研究组(n=40,MVD联合PSR治疗),比较两组患者疼痛评分、生活质量、围术期指标、睡眠状况、并发症发生情况以及复发率。结果:两组患者治疗后视觉疼痛模拟量表(VAS)评分均较治疗前下降,且研究组低于对照组(P<0.05)。两组患者治疗后生活质量量表(SF-36)各维度评分均较治疗前升高,且研究组高于对照组(P<0.05)。两组患者治疗后匹兹堡睡眠质量指数表(PSQI)各项目评分均较治疗前升高,且研究组高于对照组(P<0.05)。研究组住院时间短于对照组,手术时间长于对照组(P<0.05);两组术中出血量比较无统计学差异(P>0.05)。研究组的并发症总发生率低于对照组(P<0.05)。两组随访期间复发率比较差异无统计学意义(P>0.05)。结论:MVD联合PSR治疗原发性TN,虽然手术时间较长,但是在减轻患者疼痛、改善患者生活质量及睡眠状况等方面效果显著,能够降低并发症发生率。  相似文献   
89.
Purinergic Signalling - Purinergic signalling plays important roles in somatosensory and nociceptive transmission in the dorsal horn of the spinal cord under physiological and pathophysiological...  相似文献   
90.
BackgroundChest pain is a common symptom in urgent primary care. The distinction between urgent and non-urgent causes can be challenging. A modified version of the HEART score, in which troponin is omitted (‘simplified HEART’) or replaced by the so-called ‘sense of alarm’ (HEART-GP), may aid in risk stratification.MethodThis study involved a retrospective, observational cohort of consecutive patients evaluated for chest pain at a large-scale, out-of-hours, regional primary care facility in the Netherlands, with 6‑week follow-up for major adverse cardiac events (MACEs). The outcome of interest is diagnostic accuracy, including positive predictive value (PPV) and negative predictive value (NPV).ResultsWe included 664 patients; MACEs occurred in 4.8% (n = 32). For  simplified HEART and HEART-GP, we found C‑statistics of 0.86 (95% confidence interval (CI) 0.80–0.91) and 0.90 (95% CI 0.85–0.95), respectively. Optimal diagnostic accuracy was found for a simplified HEART score ≥2 (PPV 9%, NPV 99.7%), HEART-GP score ≥3 (PPV 11%, NPV 99.7%) and HEART-GP score ≥4 (PPV 16%, NPV 99.4%). Physicians referred 157 patients (23.6%) and missed 6 MACEs. A simplified HEART score ≥2 would have picked up 5 cases, at the expense of 332 referrals (50.0%, p < 0.001). A HEART-GP score of ≥3 and ≥4 would have detected 5 and 3 MACEs and led to 293 (44.1%, p < 0.001) and 186 (28.0%, p = 0.18) referrals, respectively.ConclusionHEART-score modifications including the physicians’ ‘sense of alarm’ may be used as a risk stratification tool for chest pain in primary care in the absence of routine access to troponin assays. Further validation is warranted.Supplementary InformationThe online version of this article (10.1007/s12471-020-01529-4) contains supplementary material, which is available to authorized users.  相似文献   
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