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101.
V. A. Polunovskii 《Bulletin of experimental biology and medicine》1975,80(1):815-817
Under the influence of 1 mM cyclic-adenosine-3,5-monophosphate (cyclic-AMP) the degree of survival and rate of reproduction of Chinese hamster cells in culture were reduced to 27 and 42% of the control level, respectively. Addition of 0.02 mM thymidine along with the cyclic-AMP almost completely abolished the cytostatic effect of the latter. Thymidine also prevented the cytostatic effect of noncyclic 5-AMP, but did not affect death of the cells due to the action of dibutyryl cyclic-AMP and theophylline. Thymidine did not prevent the inhibitory action of cyclic-AMP on a mutant line of mouse cells deficient in thymidine kinase. It is concluded that, in the concentrations used, the cytostatic action of exogenous cyclic-AMP on mammalian cells is the result of its splitting to 5-AMP in the culture medium, and that it acts by blocking one of the stages of TMP biosynthesis.Department of Genetics and Plant Breeding, Faculty of Biology, M. V. Lomonosov Moscow University. (Presented by Academician S. E. Severin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 80, No. 7, pp. 93–95, July, 1975. 相似文献
102.
MTEC 1分泌的趋化因子引起特定亚群胸腺细胞的定向迁移 总被引:9,自引:0,他引:9
分析胸腺髓质上皮样细胞系MTEC1分泌的化学趋化因子对胸腺细胞亚群的趋化作用。方法以抗体加补体杀伤结合免疫磁珠及panning法,将小鼠胸腺细胞分离纯化,获得CD4+CD8+(DP),CD4-CD8-(DN),CD4+CD8-(CD4SP)及CD4-CD8+(CD8SP)四亚群细胞,用Boyden小室分析MTEC1┐SN对四群胸腺细胞的趋化作用。结果MTEC1┐SN对DP及CD4SP胸腺细胞有趋化活性(CI=6.6±1.0及6.1±1.8);对CD8SP细胞有中度趋化活性(CI=3.2±1.0);对DN趋化活性微弱(CI=1.3±0.6)。化学趋化因子MCP┐1纯品对CD4SP胸腺细胞显示强趋化活性(CI=5.6),对DN胸腺细胞则无可测出趋化活性。结论MTEC1分泌的化学趋化因子对DP,CD4SP及CD8SP胸腺细胞有显著趋化作用,对DN胸腺细胞几乎无趋化作用。提示此类化学趋化因子有趋使胸腺发育中后期阶段的细胞向胸腺髓质区迁移和定位的作用。 相似文献
103.
自体甲状腺组织与干细胞移植治疗甲状腺功能减退症的研究进展 总被引:1,自引:0,他引:1
不可逆性甲减患者需要终身服用甲状腺激素,对患者的日常工作和生活造成了很大的不便。随着近年来对自体甲状腺组织与干细胞移植研究的进展,有望解决甲减病人终身服药这一问题。自体甲状腺组织移植的动物实验以及人体试验均表明:甲状腺移植物不但能够存活,而且能够发挥作用。最新的胚胎干细胞(Embryonic stemcell,ESC)研究证明,ESC可以分化为甲状腺滤泡细胞。 相似文献
104.
Z. Oláh S. Komoly N. Nagashima F. Joó U. R. Rapp W. B. Anderson 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1991,83(2):403-410
Summary In this report we describe changes in the intracellular redistribution of raf serine/threonine protein kinase (product of the raf proto-oncogene family) in hippocampal neurons following cerebral ischemia in Mongolian gerbils. For immunohistochemical localization studies polyclonal antisera specific for each of the A, B, and Raf-1 isotypes of raf, as well as a pan-raf antisera, were employed. Of these, only sera recognizing B-raf, as well as the general v-raf (raised against the conserved C-terminal region) were positive, indicating that B-raf is the major isotype in this neuronal region. Three different ischemie models were used (repeated 3 times for two min and single 5 or 15 min occlusions, of the common carotid arteries) to demonstrate that ischemie insult causes redistribution of raf protein kinase into the cell nucleus of hippocampal neurons. Increased amounts of raf protein in the nuclei of pyramidal cells following ischemia was confirmed by Western blot analysis of isolated nuclear fractionations. Moreover, an elevation in the level of nuclear raf protein also was detected in the contralateral (i.e. non-occluded hemisphere) neurons of CA1 and CA3 subfields 4 days after the ischemie insult indicating a possible transsynaptic increase in the amount of raf protein along with redistribution. The intranuclear translocation of the immunoreactive material started from the perinucleolar rim and with time extended throughout the nucleus. Enhanced levels and altered redistribution of the raf polypeptide in the nuclei of pyramidal cells of the CA3 subfleld appears to be reversible and returns to the normal level 12 days following the ischemic insult. In addition to triggering the above changes in the intracellular redistribution of raf, ischemie insult also caused an increase in the level of B-raf protein in reactive astrocytes. 相似文献
105.
106.
It is well known that the hypolipidemic drug ciprofibrate induces peroxisome proliferation in rodent liver, which in turn leads to the oxidative stress, and modifies some parameters related to cell proliferation and apoptosis. The administration of ciprofibrate to rats during the lactating period determined in their pups significant modifications in hepatic peroxisome enzyme activities, induction of the PPARalpha-target gene, Cyp4a10, and perturbation in cell proliferation and apoptosis, which affected the size of the liver. Moreover, this modification was associated to about two-fold induction of mRNA-PPARalpha. On the contrary, in the kidney, although a similar two-fold up-regulation of PPARalpha was detected, the induction of both peroxisomal enzyme activities and Cyp4a10 were weak, and no alterations were detected, neither in cell cycle nor in the size of the tissue. Our results indicate that the response to ciprofibrate is stronger in the liver than in the kidney of newborn rats. 相似文献
107.
The genome of equine arteritis virus (EAV) produces a 3 coterminal-nested set of six subgenomic (sg) viral RNAs during virus replication cycle, and each set possesses a common leader sequence of 206 nucleotides (nt) in length derived from the 5 end of the viral genome. Given the presence of the leader region within both genomic and sg mRNAs, it is likely to contain cis-acting signals that may interact with cellular or viral proteins for RNA synthesis. Gel mobility shift assays indicated that proteins in Vero cell cytoplasmic extracts formed complexes with the positive (+) and negative (-) strands of the EAV leader RNA. Several cell proteins with molecular masses ranging from 74 to 31 kDa and 58 to 32 kDa were detected in UV-induced cross-linking assays with the EAV leader RNA (+) and (-) strands, respectively. In both cases, intense bands were observed at the 58–52 kDa molecular weight markers. Results from competition gel mobility shift assays using overlapping cold RNA probes spanning the leader RNA (+) strand indicated that nt 140–206 are not necessary for binding to cell proteins. 相似文献
108.
培养细胞整装内质网三维结构的多态性 总被引:3,自引:0,他引:3
用高锰酸钾-锇酸固定法制备了5种培养细胞整装内质网标本,并在扫描电镜下对其三维结构进行了观察。观察结果表明内质网是由膜性小管构成的贯穿整个细胞质的管囊网络样膜性区室,并以多种形态深入到细胞伪足及突起中;细胞质中内质网则表现为簇状网络(见于GCM3T3细胞)、多态性多孔扁囊样网络、筛网状网络、条索状网络、大孔条索网状和细孔扁囊样分区网络、不规则管网状和多孔管囊分区网络(见于CV-1细胞)、细管网络(见于CCL187和CCL229细胞)、球囊网络(见于CCL187和A431细胞)和不规则管网状网络(见于A431细胞)等。内质网的这种多态性提示它是一种高度可变的结构,其可变性可能与细胞特性、分化程度、细胞功能状态及细胞骨架系统的分布变化等因素有关。 相似文献
109.
本文对转染PSV_2-neo质粒后的Wg3h细胞系(Wg3h-neo)在长期传代中的生长特性和表面超微结构与母系Wg3h细胞进行了比较研究。结果发现:转染后Wg3h细胞的DNA合成及生长速度明显高于母系Wg3h细胞,生长饱和密度增大。在软琼脂培养中不形成集落,接种在裸鼠不长肿瘤。在扫描电镜下,细胞表面的微绒毛较母系Wg3h细胞丰富。Southern印迹杂交实验证明PSV_2-neo质粒已整合到宿主细胞的基因组中。转染后Wg3h细胞的生长特性和表面超微结构均发生了某些转化特征。 相似文献
110.
人肿瘤细胞TH2类细胞因子的逆转与NK抗性变化的研究 总被引:3,自引:0,他引:3
目的研究促使人肿瘤细胞中TH2类细胞因子表达向TH0型的逆转及逆转后的肿瘤细胞对NK抗性的变化。方法首先用MTT方法对悬浮培养的肿瘤细胞株DB大淋巴细胞瘤、Karpas淋巴瘤、Michael淋巴瘤、Raji、HL60和K562进行了NK杀伤敏感性的筛选。选择NK不敏感的Karpas淋巴瘤和HL60,用rhIFNγ、rhIL-12和抗IL-10McAb经不同组合对其进行由TH2类细胞因子表达向TH1类细胞因子表达的促逆转研究,并观察促逆转后的肿瘤细胞对NK抗性的变化。结果RT-PCR结果表明,经上述不同细胞因子组合诱导后,Karpas淋巴瘤细胞均从表达TH2类细胞因子为主向TH0型逆转,并且各组逆转后的肿瘤细胞对NK的抗性均有不同程度的减弱。结论TH1类细胞因子(如IFNγ)、TH2类细胞因子拮抗剂(如IL-10单抗)和IL-12不同程度地促进肿瘤细胞表达的细胞因子由TH2型向TH0/TH1型逆转。促逆转后可以改善肿瘤细胞对机体杀伤作用的敏感性,提高抗肿瘤免疫能力 相似文献