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101.
Corticofugal amplification of facilitative auditory responses of subcortical combination-sensitive neurons in the mustached bat 总被引:2,自引:0,他引:2
Recent studies on the bat's auditory system indicate that the corticofugal system mediates a highly focused positive feedback to physiologically "matched" subcortical neurons, and widespread lateral inhibition to physiologically "unmatched" subcortical neurons, to adjust and improve information processing. These findings have solved the controversy in physiological data, accumulated since 1962, of corticofugal effects on subcortical auditory neurons: inhibitory, excitatory, or both (an inhibitory effect is much more frequent than an excitatory effect). In the mustached bat, Pteronotus parnellii parnellii, the inferior colliculus, medial geniculate body, and auditory cortex each have "FM-FM" neurons, which are "combination-sensitive" and are tuned to specific time delays (echo delays) of echo FM components from the FM components of an emitted biosonar pulse. FM-FM neurons are more complex in response properties than cortical neurons which primarily respond to single tones. In the present study, we found that inactivation of the entire FM-FM area in the cortex, including neurons both physiologically matched and unmatched with subcortical FM-FM neurons, on the average reduced the facilitative responses to paired FM sounds by 82% for thalamic FM-FM neurons and by 66% for collicular FM-FM neurons. The corticofugal influence on the facilitative responses of subcortical combination-sensitive neurons is much larger than that on the excitatory responses of subcortical neurons primarily responding to single tones. Therefore we propose the hypothesis that, in general, the processing of complex sounds by combination-sensitive neurons more heavily depends on the corticofugal system than that by single-tone sensitive neurons. 相似文献
102.
With the help of results on the metabolism and the carcinogenicactivities of polycyclic aromatic hydrocarbons (PAH), the comprehensivemetabolic process in vivo is discussed. It is thought that thecarcinogenic activity exhibited by a PAH is determined by thecompetition between the carcinogenesis and detoxification inwhich it participates. It is suggested that the essential agentof carcinogenesis should be, as a rule, the highest delocalizationenergy (ß unit) of the carbonium ion at the aromaticangular ring (A region), which is obtained by the perturbationalmolecular orbit (PMO) method. Since there are no essential distinctionsin the molecular geometry and delocalization energy states betweentwo carbonium ions of the aromatic angular ring and of the bayregion, the A region can be looked upon as the extended bayregion. On the basis of discussion of the overall metabolism,evaluation of the detoxification efficacy of each kind of thecompeting carcinogenic factors, including the biological factorB and three structural factors of the PAH molecule: K, A andL, was made. After making necessary approximation, K=0.228,A=0.5, L=1.22 and B=0.7 are obtained. It can be seen from thesevalues that the L region plays the most important role in detoxificationprocesses, and the K region plays the least important role.The effect of biological factor B is approximately the sum ofthe K region and the A region. This paper suggests the conceptof a carcinogenic constant. For the PAHs with the same numberof aromatic rings (N), C is a constant. The curve of functionC=f(N), including the extensional line, is an isosceles triangle.The author suggests that it should be called the PyramidRule. The final form of the quantitative equation is. The values for 50 PAHs which had been tested by animal experiments were calculated. Of these, 92% of thePAHs are in agreement with experiments on carcinogenic activities. 相似文献
103.
糖尿病足溃疡是糖尿病严重的破坏性并发症,致残率及致死率逐年增高,严重威胁人类身心健康。中医药治疗糖尿病足溃疡,注重辨证论治与整体观念相结合,不仅能改善中医证候,更能在加速创面愈合的同时减少创面的复发,一定程度上延缓了糖尿病足溃疡的进一步恶化,降低其致残率及致死率。现代研究发现,糖尿病足溃疡难以愈合与各种细胞因子如炎症因子、生长因子、趋化因子等分布异常密切相关;随着现代医学对中医药研究的不断深入,中药单体及复方调控细胞因子治疗糖尿病足溃疡已成为研究热点,该文通过对目前国内外研究现状进行归纳,得出以下总结:(1)芝麻酚、栀子苷、当归补血汤、紫朱软膏等调节肿瘤坏死因子-α(TNF-α)、白细胞介素(IL)-1、IL-6、IL-10等炎症因子,抑制创面炎症。(2)白芷、丹酚酸B、四效散、壮药拔毒生肌膏等调节血管内皮生长因子(VEGF)、血小板衍生生长因子(PDGF)、转化生长因子(TGF)、表皮生长因子(EGF)等生长因子,促进创面胶原沉积及血管新生。(3)芍药苷、隐丹参酮、蜂毒、回阳生肌汤等调节CXC趋化因子配体(CXCL)1、CXCL2、CC趋化因子配体(CCL)2、CCL3、基质细胞衍生... 相似文献
104.
Priyanka Sharma Guojun Wu Deeptha Kumaraswamy Natalie Burchat Hong Ye Yongjia Gong Liping Zhao Yan Y. Lam Harini Sampath 《Nutrients》2021,13(2)
7,8-Dihydroxyflavone (DHF) is a naturally occurring flavonoid that has been reported to protect against a variety of pathologies. Chronic administration of DHF prevents high-fat diet (HFD)-induced obesity in female, but not male, mice. However, the mechanisms underlying this sexual dimorphism have not been elucidated. We have discovered that oral DHF supplementation significantly attenuates fat mass, hepatic lipid accumulation, and adipose tissue inflammation in female mice. In contrast, male mice were not protected from adiposity, and had a paradoxical worsening of hepatic lipid accumulation and adipose tissue inflammation upon DHF supplementation. Consistent with these sexually dimorphic effects on body weight and metabolic health, 7,8-DHF induced early and stable remodeling of the female intestinal microbiome. DHF supplementation significantly increased gut microbial diversity, and suppressed potentially detrimental bacteria, particularly Desulfovibrionaceae, which are pro-inflammatory and positively associated with obesity and inflammation. Changes in the female gut microbiome preceded alterations in body weights, and in silico analyses indicated that these early microbial changes were highly predictive of subsequent weight gain in female mice. While some alterations in the intestinal microbiome were also observed in male DHF-supplemented mice, these changes were distinct from those in females and, importantly, were not predictive of subsequent body weight changes in male animals. The temporality of microbial changes preceding alterations in body weight in female mice suggests a role for the gut microbiome in mediating the sexually dimorphic effects of DHF on body weight. Given the significant clinical interest in this flavonoid across a wide range of pathologies, further elucidation of these sexually dimorphic effects will aid the development of effective clinical therapies. 相似文献
105.
人工流产术前宫颈及子宫内膜麻醉的镇痛效果探讨 总被引:1,自引:0,他引:1
目的 探讨宫颈与子宫内膜两部位联合麻醉、普鲁卡因与利多卡因两药物配合应用在人工流产术中的镇痛效果。方法 人工流产术前对麻醉组 10 6例行普鲁卡因宫颈浸润麻醉和利多卡因子宫内膜表面麻醉。术中记录受术者腹痛程度、无阻力插入宫颈内口的扩张器号、出血量、人流综合征例数等指标。按照世界卫生组织规定疼痛标准及人工流产综合征反应进行评价 ,同期选择按传统机械扩宫法 10 4例做对照。结果 麻醉组镇痛有效率95 3% ,宫口松驰有效率 95 3% ,人流综合征无 1例发生。两组比较P均 <0 0 0 1。两组出血量比较无差异 ,无利多卡因毒性反应发生。结论 人工流产术前普鲁卡因宫颈浸润麻醉和利多卡因子宫内膜表面麻醉镇痛效果显著 ,可大大降低人流综合征的发生 ,避免利多卡因的毒性反应 相似文献
106.
张雁 《菏泽医学专科学校学报》2001,13(4):47-49
目的 研究PCEA对病人术后转归的影响。方法 100例均行硬膜外穿刺的手术,随机等分为两组即PCEA(A)组和未实施PCEA(B)组。定时监测两组MAP,HR,SPO2,RR;选择其中30例食管,胃肠道手术,除监测以上项目外,并于入手术室后硬膜外穿刺前(T0),术始60分钟(T1),术毕24小时(T2)时分别测定病人皮质醇,血糖,胃粘膜pH的变化情况。结果 A组镇痛期间MAP,HR,SPO2,RR,血糖,胃粘膜pH均变化不大,术后皮质醇浓度下降,镇痛确切,病人平干静合作,满意度高;B组镇痛期间除皮质醇浓度变化不大外,其余指标均波动明显,镇痛效果差,病人呈焦虑状态,满意度差。结论 PCEA利于病人术后转归。 相似文献
107.
目的:探讨知觉性斜视的病因,临床特点,治疗方法及预后,方法:根据不同病情采取手术治疗,弱视训练及配戴三棱镜。结果:手术的29例眼位正,1例术后配戴三棱镜矫正眼位,1例先天性白内障术后经弱视训练视力改善后矫正眼位,24例无双眼单视功能,结论:及早发现各种引起知觉斜视的病因预以治疗,以促进双眼单视功能的发育。 相似文献
108.
目的:为临床应用混合抗体进行放射免疫治疗提供实验依据。方法:在裸鼠荷人大肠癌Lovo移植瘤生长至1cm时,瘤内分别或同时注射~(131)I标记的抗CL_3单克隆抗体(~(131)I-CL_3)和~(131)I标记抗FERR单克隆抗体T_9(~(131)I-T_9),治疗后行SPECT显像观察标记抗体在肿瘤内的浓聚,并进行疗效观察。结果:我们发现两种抗体混合治疗组疗效明显好于单独治疗组,抗体在肿瘤内的浓聚也大于单独应用。结论:多种抗体混合应用瘤内注射放射免疫治疗可增加标记抗体在肿瘤内的浓聚,并能提高放射免疫治疗的疗效。 相似文献
109.
海南省山区霍乱流行病学分析 总被引:2,自引:1,他引:1
目的 为了解海南省山区的霍乱流行特点,为今后更好地预防、控制山区的霍乱流行提供理论依据。方法 采用统一制定的霍乱个案调查表和流行病学调查表进行调查,然后做统计分析。结果 1994~1998年,海南省山区发生6起食物型霍乱爆发疫情,发病191例,罹患率13.12%,病死6例,病死率3.14%。患者皆为黎族居民,各年龄组均有发病,以20~40岁组的青壮年所占比例最高,为67.54%。男性患者(65.97%)明显多于女性(34.03%)。疫情波及4个县(市)、8个乡(镇)、40个自然村。轻型病例仍然占大多数(62.30%)。对82株菌株的鉴定结果全部为小川lb型,与该省沿海地区自1994年后以小川1b型为优势流行株相一致。结论 导致这6起霍乱爆发的最主要原因是丧事聚餐,可疑食物均来自某市的海鱼。 相似文献
110.