全文获取类型
收费全文 | 75228篇 |
免费 | 7962篇 |
国内免费 | 4957篇 |
专业分类
耳鼻咽喉 | 585篇 |
儿科学 | 1268篇 |
妇产科学 | 678篇 |
基础医学 | 6741篇 |
口腔科学 | 1515篇 |
临床医学 | 9158篇 |
内科学 | 9458篇 |
皮肤病学 | 775篇 |
神经病学 | 3448篇 |
特种医学 | 3167篇 |
外国民族医学 | 27篇 |
外科学 | 7500篇 |
综合类 | 15983篇 |
现状与发展 | 13篇 |
一般理论 | 2篇 |
预防医学 | 6523篇 |
眼科学 | 2000篇 |
药学 | 8283篇 |
55篇 | |
中国医学 | 5851篇 |
肿瘤学 | 5117篇 |
出版年
2024年 | 308篇 |
2023年 | 1126篇 |
2022年 | 2816篇 |
2021年 | 3687篇 |
2020年 | 2980篇 |
2019年 | 2377篇 |
2018年 | 2416篇 |
2017年 | 2530篇 |
2016年 | 2299篇 |
2015年 | 3350篇 |
2014年 | 4275篇 |
2013年 | 4600篇 |
2012年 | 6482篇 |
2011年 | 6682篇 |
2010年 | 5181篇 |
2009年 | 4414篇 |
2008年 | 4870篇 |
2007年 | 4705篇 |
2006年 | 4462篇 |
2005年 | 3704篇 |
2004年 | 2993篇 |
2003年 | 2721篇 |
2002年 | 2155篇 |
2001年 | 1707篇 |
2000年 | 1272篇 |
1999年 | 943篇 |
1998年 | 508篇 |
1997年 | 563篇 |
1996年 | 400篇 |
1995年 | 331篇 |
1994年 | 307篇 |
1993年 | 187篇 |
1992年 | 144篇 |
1991年 | 135篇 |
1990年 | 120篇 |
1989年 | 89篇 |
1988年 | 84篇 |
1987年 | 68篇 |
1986年 | 57篇 |
1985年 | 28篇 |
1984年 | 18篇 |
1983年 | 21篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1970年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
乙醇对人绒毛孕酮分泌的影响 总被引:1,自引:0,他引:1
本工作利用灌流技术观察了四种不同浓度的乙醇(0.5%、1%、2.5%、5%)对妊娠早期人工流产新鲜胎盘绒毛分泌孕酮的影响。结果表明,乙醇具有促进孕酮分泌的作用,并存在剂量依赖的关系。提示乙醇可能破坏胎盘激素内分泌的平衡,从而影响胎儿的正常生长与发育。 相似文献
42.
Schecter AD Berman AB Yi L Ma H Daly CM Soejima K Rollins BJ Charo IF Taubman MB 《Journal of leukocyte biology》2004,75(6):1079-1085
Monocyte chemoattractant protein-1 (MCP-1, CCL2) is a mediator of inflammation that has been implicated in the pathogenesis of a wide variety of human diseases. CCR2, a heterotrimeric G-coupled receptor, is the only known receptor that functions at physiologic concentrations of MCP-1. Despite the importance of CCR2 in mediating MCP-1 responses, several recent studies have suggested that there may be another functional MCP-1 receptor. Using arterial smooth muscle cells (SMC) from CCR2(-/-) mice, we demonstrate that MCP-1 induces tissue-factor activity at physiologic concentrations. The induction of tissue factor by MCP-1 is blocked by pertussis toxin and 1,2-bis(O-aminophenyl-ethane-ethan)-N,N,N',N'-tetraacetic acid-acetoxymethyl ester, suggesting that signal transduction through the alternative receptor is G(alphai)-coupled and dependent on mobilization of intracellular Ca(2+). MCP-1 induces a time- and concentration-dependent phosphorylation of the mitogen-activated protein kinases p42/44. The induction of tissue factor activity by MCP-1 is blocked by PD98059, an inhibitor of p42/44 activation, but not by SB203580, a selective p38 inhibitor. These data establish that SMC possess an alternative MCP-1 receptor that signals at concentrations of MCP-1 that are similar to those that activate CCR2. This alternative receptor may be important in mediating some of the effects of MCP-1 in atherosclerotic arteries and in other inflammatory processes. 相似文献
43.
动脉导管溶栓治疗急性肢体动脉栓塞14例分析 总被引:3,自引:0,他引:3
目的 探讨动脉导管溶栓治疗急性肢体动脉栓塞的方法和疗效。方法回顾性分析14例肢体动脉栓塞的诊断方法和介入手术治疗方案。结果治愈11例,治愈率78.6%(11/14);2例好转。无患肢缺血坏死或截肢,无术后因肾功能衰竭死亡。结论动脉导管溶栓是治疗急性肢体动脉栓塞有效的方法,值得进一步开展和探索。 相似文献
44.
乙型肝炎病毒前S1抗原检测及其临床意义 总被引:10,自引:0,他引:10
为探讨检测乙型肝炎病毒前S1抗原(Pre-S1Ag)的临床意义,本文对338例各型乙型肝炎患者进行Pre-S1Ag检测,同时检测HBV标志物和HBV-DNA,对其阳性率及相互关系进行分析比较.结果表明:338例患者,Pre-S1Ag阳性检测率为63.02%,HBeAg阳性检测率为48.52%,HBV-DNA阳性检测率为68.05%.Pre-S1Ag阳性与HBV-DNA阳性的符合率为78.56%;Pre-S1Ag与HBeAg阳性的符合率为81.17%;Pre-S1Ag与HBeAg、HBV-DNA具有显著相关性(P<0.01),提示Pre-S1Ag能够较好地反映病毒复制状况,有可能作为体内病毒复制存在的实验室指标. 相似文献
45.
Multi-virulence-locus sequence typing clarifies epidemiology of recent listeriosis outbreaks in the United States 总被引:2,自引:0,他引:2
Multi-virulence-locus sequence typing (MVLST) was used to analyze isolates from two major listeriosis outbreaks in the United States in 1998 and 2002 that were due to consumption of contaminated hot dogs and turkey deli meat, respectively. MVLST demonstrated high epidemiological relevance and indicated that the two outbreaks were the result of one epidemic. 相似文献
46.
氧化苦参碱对LAK细胞活性的影响 总被引:18,自引:0,他引:18
LAK细胞具有很强的广谱杀瘤作用,而氧化苦参碱具有较强的免疫抑制作用。本文研究了氧化苦参碱对LAK细胞活力的影响,结果表明:氧化苦参碱可抑制IL-2对小鼠脾细胞的促增殖作用,并且对IL-2活化LAK细胞杀伤P815的能力也有抑制作用。当IL-2(500u/ml)与200μg/ml的氧化苦参碱共同孵育4d后,可使LAK细胞杀瘤能力(在效靶比为100:1时)的82.5%被抑制。同时氧化苦参碱本身对P8 相似文献
47.
Jian-Zhong Zhang Li Jing Feng-Ying Guo Yi Ma Yi-Li Wang 《Experimental and toxicologic pathology》2007,59(3-4):227-235
To determine if the inhibitory effects of ketamine on the extracellular signal-regulated kinase (ERK) 1/2 are involved in reduction of the hyperglycemia-exaggerated cerebral ischemic lesion, rats with normoglycemia, hyperglycemia, or hyperglycemia supplemented with ketamine were subjected to 15 min of forebrain ischemia, and then, reperfusion for 0.5, 1, and 3h. Phosphorylation of ERK1/2 in the brain tissues was assessed by immunohistochemistry and Western blot analysis. In rats with normoglycemia, we demonstrated a moderate increase of the ERK1/2 phosphorylation in the cingulum cortex and hippocampus CA3 following an ischemic intervention. It quickly dropped to control levels after reperfusion for 0.5h. In rats with hyperglycemia, however, the increase of the ERK1/2 phosphorylation in these areas was significantly higher in all animals reperfused. The neuronal death, detected by the TdT-mediated-dUTP nick end labeling assays, was found in the cingulum cortex (5.23+/-2.34, per high power feild) and hippocampus CA3 areas (6.29+/-3.68, per 1mm(2)) in hyperglycemic group after reperfusion for 3h. With ketamine treatment, the ERK1/2 phosphorylation in cingulum cortex and hippocampus CA1 and CA3 areas was found to be the same as that in normoglycemia rats. Our results suggest that hyperglycemia may increase the ischemic insult through modulation of the signal transduction pathways involving ERK1/2. The inhibitory effects of ketamine on the hyperglycemia-activated ERK1/2 phosphorylation are probably through inhibition of the N-methyl d-aspartate-mediated calcium influx, which subsequently reduce the hyperglycemia-exaggerated cerebral damage. 相似文献
48.
Hepatocytes are anchorage-dependent cells sensitive to microenvironment; the control of the physicochemical properties of the extra-cellular matrices may be useful to the maintenance of hepatocyte functions in vitro for various applications. In a microcapsule-based 3-D hepatocyte culture microenvironment, we could control the physical properties of the collagen nano-fibres by fine-tuning the complex-coacervation reaction between methylated collagen and terpolymer of hydroxylethyl methacrylate-methyl methacrylate-methylacrylic acid. The physical properties of the nano-fibres were quantitatively characterized using back-scattering confocal microscopy to help optimize the physical support for hepatocyte functions. We further enhanced the chemical properties of the collagen nano-fibres by incorporating galactose onto collagen, which can specifically interact with the asialoglycoprotein receptor on hepatocytes. By correlating a range of collagen nano-fibres of different physicochemical properties with hepatocyte functions, we have identified a specific combination of methylated and galactosylated collagen nano-fibres optimal for maintaining hepatocyte functions in vitro. A model of how the physical and chemical supports interplay to maintain hepatocyte functions is discussed. 相似文献
49.
50.
Metastatic tumors in the sellar and parasellar regions: clinical review of four cases 总被引:1,自引:0,他引:1
Metastatic tumors in the sellar and parasellar regions are uncommon and rarely detected in clinical practice. We present four cases of sellar and parasellar metastatic tumors, which metastasized from distant organ in one case and extended directly from adjacent structures in three. Common presenting symptoms were cranial neuropathies, headache and facial pain. Invasion into the cavernous sinus was noted in all cases. We report rare cases of sellar and parasellar metastases. Also, we should consider the possibility of metastasis in these regions for patients who showed the above clinical presentations in systemic cancer patients. In extensive diseases, transient symptomatic relief could be obtained by direct surgical management, even in restricted degree. 相似文献