全文获取类型
收费全文 | 8061篇 |
免费 | 566篇 |
国内免费 | 165篇 |
专业分类
耳鼻咽喉 | 45篇 |
儿科学 | 235篇 |
妇产科学 | 119篇 |
基础医学 | 1456篇 |
口腔科学 | 107篇 |
临床医学 | 391篇 |
内科学 | 1196篇 |
皮肤病学 | 139篇 |
神经病学 | 730篇 |
特种医学 | 338篇 |
外科学 | 1230篇 |
综合类 | 532篇 |
现状与发展 | 1篇 |
一般理论 | 1篇 |
预防医学 | 264篇 |
眼科学 | 67篇 |
药学 | 995篇 |
1篇 | |
中国医学 | 215篇 |
肿瘤学 | 730篇 |
出版年
2024年 | 19篇 |
2023年 | 118篇 |
2022年 | 177篇 |
2021年 | 254篇 |
2020年 | 199篇 |
2019年 | 311篇 |
2018年 | 284篇 |
2017年 | 217篇 |
2016年 | 208篇 |
2015年 | 231篇 |
2014年 | 441篇 |
2013年 | 469篇 |
2012年 | 358篇 |
2011年 | 472篇 |
2010年 | 399篇 |
2009年 | 433篇 |
2008年 | 415篇 |
2007年 | 418篇 |
2006年 | 431篇 |
2005年 | 370篇 |
2004年 | 321篇 |
2003年 | 277篇 |
2002年 | 233篇 |
2001年 | 172篇 |
2000年 | 154篇 |
1999年 | 115篇 |
1998年 | 121篇 |
1997年 | 106篇 |
1996年 | 157篇 |
1995年 | 79篇 |
1994年 | 64篇 |
1993年 | 52篇 |
1992年 | 60篇 |
1991年 | 39篇 |
1990年 | 22篇 |
1989年 | 27篇 |
1988年 | 19篇 |
1986年 | 27篇 |
1985年 | 57篇 |
1984年 | 62篇 |
1983年 | 43篇 |
1982年 | 61篇 |
1981年 | 43篇 |
1980年 | 44篇 |
1979年 | 36篇 |
1978年 | 35篇 |
1977年 | 23篇 |
1976年 | 33篇 |
1975年 | 25篇 |
1974年 | 19篇 |
排序方式: 共有8792条查询结果,搜索用时 15 毫秒
91.
2型糖尿病为影响人类生存质量的主要病因之一,在过去十年里,2型糖尿病在全球范围的发病率显著增加[1].其主要特征是胰岛素相对不足和存在胰岛素抵抗.2型糖尿病的胰岛素抵抗作用和人体肝脏、骨骼肌及脂肪组织中的胰岛素信号转导通路紊乱关系密切[2]. 相似文献
92.
儿童肿瘤性疾病的化学治疗目前趋向于较大剂量,以达到降低复发率、提高预后和生存质量之目的。而由此往往导致严重骨髓抑制,血小板减少是其中一个重要表现,往往发生严重的出血,甚至导致患者的死亡。为此临床采用大量的血小板输注以帮助患者度过血小板减少期.但其费用昂贵,且合并症较多。寻找缩短血小板减少时间的治疗方法是临床努力的方向。笔者用IL-11(巨和粒,山东齐鲁制药030201)合并使用血小板输注治疗22例骨髓抑制合并血小板减少的患者儿.并以同期患者20例为对照,进行了比较性研究.取得了较好的疗效,现报告如下。 相似文献
93.
目的 探讨电离辐射是否对成纤维细胞和血管内皮细胞的增殖游走功能具有直接抑制作用及其抑制程度,以及W11-a12的促愈使用。方法 采用培养的单层3T3细胞(小鼠胚胎FBs株)和培养的单层ECV304细胞(人脐静脉内皮细胞株)划痕伤口模型进行离体照射,观察痕隙闭合速度。结果 在6Gy照射后培养的单层3T3细胞与单层L-ECV304细胞划痕“伤口”闭合明显延缓。单层3T3细胞在伤后10h对照组伤口完全闭合,而照射组仅闭合77%;照射组单层ECV304细胞在伤后12h仅为对照组的83.6%。W11-a12用药组对单层3T3细胞与ECV304细胞“划痕”伤口的闭合均有促进作用。结论 放射损伤对成纤维细胞与血管内皮细胞的增殖游走有直接抑制作用,这是伤口难愈的重要原因之一。促进伤口细胞游走和增殖是W11-a12作用的一个重要途径。 相似文献
94.
Despite the obvious importance of limbal stem cells in corneal homeostasis and tumorigenesis, little is known about their specific biological characteristics. The purpose of this study was to characterize limbal slow-cycling cells based on the expression of ABCG2 and major histocompatibility complex (MHC) class II and the cell size. Wistar rats were daily injected with 5-bromo-2-deoxyuridine (BrdU) at a dose of 5 mg/100 g for 2 weeks. After 4-week BrdU-free period, corneal tissues were excised, and immunofluorescence staining for ABCG2, BrdU, and MHC class II was performed by confocal microscopy. In another series, corneal tissues of normal rat were double immunostained for ABCG2, keratin 14, keratin 3, CD11c, and MHC class II. In addition, limbal, peripheral and central corneal epithelial sheets were isolated by Dispase II digestion and dissociated into single cell by trypsin digestion and cytospin preparations were double immunostained for ABCG2 and MHC class II. The cell size and nucleus-to-cytoplasm (N/C) ratio of limbal ABCG2+ cells were analyzed and compared with those of cells from other zones. BrdU label-retaining cells (LRCs) with expression of ABCG2 were found in the limbal epithelial basal layer, but not in other parts of the cornea. Approximately 20% of these cells were MHC class II positive. All MHC class II+ cells in the corneal epithelium were positive for CD11c, a marker for dendritic cells (DCs). Double labeling with ABCG2 and keratin 14 showed that nearly four-fifth of limbal ABCG2+ cells were positive for keratin 14 but negative for keratin 3, exhibiting an undifferentiated epithelial cell lineage. Cytospin sample analysis revealed the presence of a distinct population of smaller ABCG2+ cells with expression of MHC class II with a larger N/C ratio in the limbal epithelium. A new population of small slow-cycling cells with large N/C ratio has been found to express ABCG2 in the limbal epithelial basal layer. Some of these cells normally express MHC class II antigen. These findings may have important implications for our understanding of the characteristics of limbal slow-cycling cells. 相似文献
95.
黄芪多糖对B16-F10荷瘤鼠髓样抑制细胞免疫活性的影响 总被引:2,自引:0,他引:2
目的:观察黄芪多糖对B16-F10荷瘤鼠髓样抑制细胞免疫活性的影响,探讨黄芪多糖在抗肿瘤免疫机制方面所发挥的作用。方法:建立B16-F10荷瘤鼠模型,通过计算抑瘤率观察黄芪多糖的体内抗肿瘤活性;通过流式细胞术检测脾脏中Gr-1+CD11b+髓样抑制细胞比例;采用酶联免疫吸附试验检测血清中IL-10、VEGF水平。结果:与模型组相比,黄芪多糖治疗可以明显抑制荷瘤鼠黑色素瘤的生长,且可以降低荷瘤鼠脾脏Gr-1+CD11b+髓样抑制细胞比例,抑制外周血VEGF、IL-10的分泌,有显著性差异。结论:适当浓度的黄芪多糖可能通过降低髓样抑制细胞的比例,抑制VEGF、IL-10的分泌和肿瘤的生长。 相似文献
96.
F. Pisani A. Haj-Yehia A. Fazio C. Artesi G. Oteri E. Perucca D. L. Kroetz R. H. Levy M. Dialer 《Epilepsia》1993,34(5):954-959
Six patients stabilized with carbamazepine (CBZ) therapy received an 8-day “add-on” supplement of valnoctamide (VCD), a tranquilizer available over the counter (OTC) in several European countries that exhibits promising anticonvulsant activity in animal models. During VCD intake, serum levels of the active CBZ metabolite, carbamazepine-10,ll-epoxide (CBZ-E), increased fivefold from 1.5 ± 0.7 μg/ml at baseline to 7.4 ± 4.4 μg/ml after 4 days of VCD therapy and 7.7 ± 3.1 ^g/ml after 7 days of VCD therapy (means ± SD, p < 0.01). In 4 patients, the increase in serum CBZ-E levels was associated with clinical signs of CBZ intoxication. CBZ-E levels returned to baseline after VCD therapy was discontinued. Serum CBZ levels remained stable throughout the study. The interaction observed in this study is similar to that described in patients treated with CBZ and valpromide (VPD, an isomer of VCD). In a mechanistic study, therapeutic concentrations of VCD inhibited hydrolysis of styrene oxide in human liver mi-crosome preparations. Thus, VCD is a potent inhibitor of microsomal epoxide hydrolase (IC50 15 μM). There was a striking similarity between in vitro and in vivo inhibition potencies. In this study, VCD clearance was higher in epileptic patients (treated with CBZ) than in healthy subjects. 相似文献
97.
目的:回顾总结腧穴学科十一五期间(2006~2010年)取得的主要研究成果,并对腧穴研究未来的发展进行展望。方法:检索国家奖励办等相关网站及中国学术期刊网络出版总库发布或刊载的在研究立项等方面与腧穴研究相关的重要成果。结果:2项研究被列入国家重点基础研究发展计划(973计划),8项成果分获中国针灸学会和中华中医药学会科学技术奖,3项国家标准和1项国际标准确立,经穴效应具有特异性等一些新学术观点受到国内外学术界关注,23项专利获国家授权,多项新技术得以应用,《针灸单穴临床研究》等多部学术专著出版。结论:基于以上研究成果,腧穴研究将以提高临床疗效和阐释科学内涵为根本目的,在十二五期间取得新的更重要成果。 相似文献
98.
Clint L. Miller Amy R. Kontorovich Ke Hao Lijiang Ma Conrad Iyegbe Johan L.M. Björkegren Jason C. Kovacic 《Journal of the American College of Cardiology》2021,77(20):2531-2550
In this second of a 5-part Focus Seminar series, we focus on precision medicine in the context of vascular disease. The most common vascular disease worldwide is atherosclerosis, which is the primary cause of coronary artery disease, peripheral vascular disease, and a large proportion of strokes and other disorders. Atherosclerosis is a complex genetic disease that likely involves many hundreds to thousands of single nucleotide polymorphisms, each with a relatively modest effect for causing disease. Conversely, although less prevalent, there are many vascular disorders that typically involve only a single genetic change, but these changes can often have a profound effect that is sufficient to cause disease. These are termed “Mendelian vascular diseases,” which include Marfan and Loeys-Dietz syndromes. Given the very different genetic basis of atherosclerosis versus Mendelian vascular diseases, this article was divided into 2 parts to cover the most promising precision medicine approaches for these disease types. 相似文献
99.
Robin A. Aglietti Alberto Estevez Aaron Gupta Monica Gonzalez Ramirez Peter S. Liu Nobuhiko Kayagaki Claudio Ciferri Vishva M. Dixit Erin C. Dueber 《Proceedings of the National Academy of Sciences of the United States of America》2016,113(28):7858-7863
Gasdermin-D (GsdmD) is a critical mediator of innate immune defense because its cleavage by the inflammatory caspases 1, 4, 5, and 11 yields an N-terminal p30 fragment that induces pyroptosis, a death program important for the elimination of intracellular bacteria. Precisely how GsdmD p30 triggers pyroptosis has not been established. Here we show that human GsdmD p30 forms functional pores within membranes. When liberated from the corresponding C-terminal GsdmD p20 fragment in the presence of liposomes, GsdmD p30 localized to the lipid bilayer, whereas p20 remained in the aqueous environment. Within liposomes, p30 existed as higher-order oligomers and formed ring-like structures that were visualized by negative stain electron microscopy. These structures appeared within minutes of GsdmD cleavage and released Ca2+ from preloaded liposomes. Consistent with GsdmD p30 favoring association with membranes, p30 was only detected in the membrane-containing fraction of immortalized macrophages after caspase-11 activation by lipopolysaccharide. We found that the mouse I105N/human I104N mutation, which has been shown to prevent macrophage pyroptosis, attenuated both cell killing by p30 in a 293T transient overexpression system and membrane permeabilization in vitro, suggesting that the mutants are actually hypomorphs, but must be above certain concentration to exhibit activity. Collectively, our data suggest that GsdmD p30 kills cells by forming pores that compromise the integrity of the cell membrane.Pyroptosis is an inflammatory form of programmed cell death that occurs in response to microbial products in the cytoplasm or to cellular perturbations caused by diverse stimuli, including crystalline substances, toxins, and extracellular ATP (1, 2). Pyroptosis plays a critical role in the clearance of intracellular bacteria (3), but may also contribute to autoinflammatory and autoimmune disease pathology. Mechanistically, pyroptosis occurs when cytosolic nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs), including NLRP1, NLRP3, and NLRC4, or the pyrin domain-containing protein AIM2, nucleate a canonical inflammasome complex that activates the protease caspase-1 (2). Alternatively, intracellular lipopolysaccharide (LPS) from Gram-negative bacteria can trigger noncanonical activation of mouse caspase-11 and human caspases 4 and 5 (4–7). Caspases 1, 4, 5, and 11 can each cleave Gasdermin-D (GsdmD) to mediate pyroptotic cell death (8, 9). It is the N-terminal p30 fragment of GsdmD that is cytotoxic to cells, but precisely how it kills cells is unknown.Here we show that the human GsdmD p30 fragment liberated by active caspase-11 forms ring-like structures within membranes that function as pores. Therefore, we propose p30 kills cells by directly compromising the integrity of cellular membranes. We also show that the GsdmD I105N mutant that was unable to mediate macrophage pyroptosis (9) is hypomorphic at cell killing in a transient overexpression system and at liposome permeabilization in vitro—conditions where p30 concentration favors oligomerization. 相似文献
100.