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991.
992.
Ten humanCoxiella burnetii isolates from french patients with acute hepatitis or chronic endocarditis were characterized according to their polymorphism in DNA restriction patterns and differentiated by plasmid-specific PCR. The aim of this investigation was to clarify if the present classification of so called acute and chronicCoxiella burnetii isolates — based on plasmid profile of a so far limited number of partly ancient isolates — could be confirmed with lately isolated organisms of this agent. The data obtained in this investigation indicate that this classification based onC. burnetii plasmid content is no longer justified. 相似文献
993.
中风是一致死率和致残率极高的危急重症,其急性期的治疗直接关系到疾病的预后。本文探讨将中医辨证与西医医技检查手段相结合以认识、辨治本病,以求提高治愈率,减低致死率和致残率。 相似文献
994.
995.
脐血血管内皮祖细胞的分离和诱导分化 总被引:7,自引:2,他引:7
目的 从脐血中分离内皮祖细胞,诱导其向内皮细胞分化,研究内皮祖细胞的生物学特性和诱导分化条件。方法 从新鲜脐血中纯化的CD133^ 细胞接种于添加了VEGF、bFGF、IGF—1的M199培养液中,观察梭形贴壁细胞的出现时间和特异性细胞标志。结果 培养3—4d可观察到梭形贴壁细胞,14d左右可形成索条状结构,贴壁细胞表达血管内皮细胞特异性标志VE-cadherin,vWF,UEA-1和VEGFR-2。结论 脐血中含有内皮祖细胞,在一定的条件下,可分化为内皮样细胞。 相似文献
996.
Carter CA 《Experimental and molecular pathology》2003,75(1):34-44
The specific signals required for actin polymerization in response to extracellular factors remain unknown. However, in many cell types, there is a correlation between actin polymerization, activation of phosphatidylinositol 3-kinase (PI 3-kinase), and the production of the second messenger phosphatidylinositol-3,4,5-triphosphate. Increased levels of PI 3-kinase have been detected during cell growth and transformation. However, PI 3-kinase is also activated during differentiation, suggesting that PI 3-kinase and its lipid products also play a role in the regulation of cellular differentiation. The newly characterized CAC-1 cell line established from a poorly differentiated human endometrial adenocarcinoma (Exp. Mol. Pathol. 69 (2000), 175) was used as a model to investigate the role of PI 3-kinase in differentiation induction. CAC-1 cells differentiated upon treatment with pharmacological doses of retinoids (1 micro M of 13-cis or all-trans), evidenced by actin filament reorganization, and cell enlargement. PI 3-kinase staining is primarily localized to perinuclear regions in untreated cells. However, retinoic acid treatment induced PI 3-kinase to relocalize throughout the cytoplasm. Subcellular fractionation and Western blotting confirmed that PI 3-kinase decreased in the particulate fraction, concurrent with retinoid-induced differentiation. Interestingly, pretreatment with the PI 3-kinase inhibitor wortmannin (100 nM) prior to retinoic acid treatment prevented retinoic acid-induced actin reorganization and cell enlargement. To distinuish whether retinoid regulation of PI 3-kinase is mediated through traditional nuclear retinoic acid receptors, the levels of retinoic acid receptor-beta (RAR-beta) protein were evaluated. Retinoid treatment did not alter RAR-beta protein levels compared to controls. These data suggest that PI 3-kinase activity and cytoplasmic relocalization are required for retinoid-induced differentiation of poorly differentiated human endometrial adenocarcinoma cells. 相似文献
997.
H. -P. Fischer M. Altmannsberger J. Kracht 《Virchows Archiv : an international journal of pathology》1988,412(3):247-253
Summary Two cases of osteoclast-type giant cell tumour of the pancreas (OGTP) are presented and compared with similar tumours of other locations and pancreatic carcinomas. One of the tumours was analyzed by immunohistochemical methods. The mononuclear stromal cells and osteoclast-like giant cells, which characterize this very rare neoplasm, reacted with an antibody against vimentin, but were not decorated by antibodies against lysozyme, alpha-1-ACHT, alpha-1-AT. Pleomorphic mononuclear cells in osteoid additionally contained osteonectin and could thus be identified as osteoblasts. Only the tumour glands stained positively with panepithelial keratin antibodies and antibodies against the keratin polypeptides 7, 18, 19. These results demonstrate for the first time the mesenchymal differentiation of the OGTP, which in some cases is also able to form epithelial structures. The immunohistochemical reactions and the characteristic morphology of the tumour show the OGTP to be an entity which must be differentiated from pancreatic carcinoma, especially from its giant cellular subtype. 相似文献
998.
999.
Summary The general histology and ultrastructural features of the developing ductus epididymidis were examined in the brown marsupial mouse, Antechinus stuartii, from April, when males were sexually immature, until August, when the adult males were involved in mating activities, just prior to the annual male die-off. Samples were also examined 3 and 6 months after the August die-off period in males kept in isolation from conspecifics during the prebreeding and breeding periods. In April, tubule diameter and epithelial height were largest in the caput and least in caudal segments but the reverse was observed thereafter. Epithelial height increased in caput segments in August and remained high in the post die-off samples. However, caput epithelial height and tubule diameters were low compared with the remainder of the duct from July until February. Luminal shape in caudal segments (10, 11 and 12) changed in June from circular to a narrow slit, and the epithelium became variable in height. The epididymal epithelium was undifferentiated with few cytoplasmic organelles in April. Differentiation occurred mostly from May to June in associaion with an increased abundance of cytoplasmic organelles, increasing prostatic weight and rising plasma androgen levels. Differentiated principal and basal cells were found in caput and corpus regions in May and in caudal segments in June in association with the de novo development of a brush border of microvilli. Few clear cells were seen in caput and corpus regions of the duct in May but they, and mitochondria-rich cells, were common throughout the duct from June. Development of the unusual structural features of the cauda epididymidis preceded the arrival of spermatozoa in June. The presence of degenerating spermatozoa and cytoplasmic droplets in the cauda at this time suggested that it was not yet capable of supporting sperm viability. There was no evidence to suggest that the presence of spermatozoa has a stimulatory effect on the epididymis. Intact sperm were observed throughout the duct from July. Free cytoplasmic droplets, which showed some evidence of degeneration, collected in large masses in the distal corpus/ proximal cauda epididymidis of adult males between aggregates of spermatozoa. Epididymal differentiation appeared complete by mid-July; few ultrastructural changes occurred after this time. Recruitment of spermatozoa into the epididymis ceased by August and was associated with a rapid decline in sperm content in the proximal caput segments. In the November and February samples, spermatozoa were present only in distal corpus and proximal cauda segments. As in some eutherian mammals, differentiation of the epididymis in A. stuartii occurs in a descending fashion from caput to cauda. Development is linked to the onset of fluid and androgen production from the testis, which is essential for developing and maintaining a suitable caudal environment for storage and survival of spermatozoa. 相似文献
1000.
目的在基因转录水平了解肝再生中肝细胞的生长和分化情况。方法用搜集网站资料和查阅相关论文等方法获得参与肝细胞生长和分化基因,用大鼠基因组230 2.0芯片检测它们在大鼠肝再生(LR)中的表达情况,通过比较手术组和假手术组中基因表达差异性以确定上述基因中的肝再生相关基因。结果初步证实上述基因中110个基因与肝再生相关。肝再生启动(PH后0.5~4h)、G0/G1过渡(PH后4~6h)、细胞增殖(PH后6~66h)、细胞分化和组织结构功能重建(PH后72~168h)等4个阶段起始表达的基因数为63、11、43和3,基因总表达的次数为63、43、101和80,表明相关基因主要在肝再生启动阶段起始表达,在不同阶段发挥作用。它们共表达上调488次,下调248次,分为6种表达方式,表明肝再生中细胞生理生化活动的多样性和复杂性。结论肝细胞生长和分化贯穿于整个肝再生中。 相似文献