全文获取类型
收费全文 | 24081篇 |
免费 | 2534篇 |
国内免费 | 996篇 |
专业分类
耳鼻咽喉 | 489篇 |
儿科学 | 148篇 |
妇产科学 | 412篇 |
基础医学 | 2385篇 |
口腔科学 | 467篇 |
临床医学 | 1664篇 |
内科学 | 1975篇 |
皮肤病学 | 284篇 |
神经病学 | 250篇 |
特种医学 | 1103篇 |
外国民族医学 | 37篇 |
外科学 | 4220篇 |
综合类 | 3557篇 |
现状与发展 | 8篇 |
预防医学 | 350篇 |
眼科学 | 180篇 |
药学 | 1003篇 |
4篇 | |
中国医学 | 347篇 |
肿瘤学 | 8728篇 |
出版年
2024年 | 56篇 |
2023年 | 391篇 |
2022年 | 822篇 |
2021年 | 1069篇 |
2020年 | 887篇 |
2019年 | 789篇 |
2018年 | 752篇 |
2017年 | 867篇 |
2016年 | 997篇 |
2015年 | 1297篇 |
2014年 | 1593篇 |
2013年 | 1390篇 |
2012年 | 1408篇 |
2011年 | 1532篇 |
2010年 | 1289篇 |
2009年 | 1248篇 |
2008年 | 1310篇 |
2007年 | 1296篇 |
2006年 | 1241篇 |
2005年 | 1144篇 |
2004年 | 917篇 |
2003年 | 825篇 |
2002年 | 702篇 |
2001年 | 583篇 |
2000年 | 544篇 |
1999年 | 463篇 |
1998年 | 431篇 |
1997年 | 332篇 |
1996年 | 242篇 |
1995年 | 206篇 |
1994年 | 174篇 |
1993年 | 123篇 |
1992年 | 113篇 |
1991年 | 84篇 |
1990年 | 71篇 |
1989年 | 65篇 |
1988年 | 58篇 |
1987年 | 50篇 |
1986年 | 38篇 |
1985年 | 39篇 |
1984年 | 36篇 |
1983年 | 25篇 |
1982年 | 21篇 |
1981年 | 25篇 |
1980年 | 24篇 |
1979年 | 16篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1976年 | 5篇 |
1974年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
L-选择蛋白在小鼠肝癌细胞高低转移株HCa-F、HCa-P的表达及与肿瘤转移潜能的相关性 总被引:7,自引:0,他引:7
目的 探讨经淋巴道转移的小鼠肝癌细胞高低转移株HCa F、HCa P淋巴道转移能力及与淋巴细胞归巢受体L 选择蛋白的相关性。方法 应用免疫印迹分析、RT PCR及流式细胞术检测小鼠肝癌HCa F、HCa P细胞表面L 选择蛋白的表达情况 ,再通过E 、P 、L 选择蛋白的抗体对细胞粘附实验的影响检测HCa F、HCa P细胞淋巴道转移潜能与L 选择蛋白的相关性。结果 L 选择蛋白在HCa F、HCa P细胞表面均有表达 ,且HCa F细胞的表达量明显高于HCa P细胞 (P <0 .0 1) ,HCa F细胞与淋巴结之间的粘附可被抗L 选择蛋白的抗体所阻断。结论 小鼠肝癌细胞高低转移株HCa F、HCa P细胞均表达L 选择蛋白 ,其程度与该细胞的淋巴道转移潜能正相关 相似文献
102.
Robinson VL Hickson JA Vander Griend DJ Dubauskas Z Rinker-Schaeffer CW 《Clinical & experimental metastasis》2003,20(1):25-30
MAP kinase kinase 4 (MKK4) is a member of the stress-activated protein kinase (SAPK) signaling cascade and is involved in the regulation of many cellular processes. We have recently demonstrated a functional role for MKK4 in the suppression of metastases. In this review, we discuss the established cellular and biochemical functions of MKK4, as well as a new function for MKK4 as a metastasis suppressor gene. Because of the importance of signaling studies to this translational work, a detailed example of the strategy and tools that can be employed to define the biochemical mechanism of MKK4-mediated metastasis suppression is presented. Finally, the potential therapeutic utility of these findings is discussed. 相似文献
103.
Inter-laboratory and inter-observer reproducibility of immunohistochemical assessment of the Ki-67 labelling index in a large multi-centre trial 总被引:23,自引:0,他引:23
Mengel M von Wasielewski R Wiese B Rüdiger T Müller-Hermelink HK Kreipe H 《The Journal of pathology》2002,196(3):292-299
The calcium-binding protein S100A4 induces the metastatic phenotype in rodent models of breast cancer and its expression correlates strongly with reduced survival in human breast cancer. The expression of S100A4 in normal bladders and 101 bladder tumours has been studied using immunocytochemistry. Moderate or strong expression of S100A4 was found in 28% of the tumours, whilst the remaining tumours and normal urothelium either failed to stain or showed weak staining. S100A4 staining was more frequently observed in invasive bladder tumours than in non-invasive tumours (p<0.05). In invasive tumours, S100A4 staining was usually strongest in invasive regions and single infiltrating cells. Statistically significant associations were found between S100A4 expression and metastasis (p=0.0003) and reduced survival (p<0.0001). It is concluded that S100A4 expression may play an important role in bladder cancer and may identify a subgroup of patients at increased risk of metastasis who should be considered for adjuvant systemic therapy. 相似文献
104.
105.
106.
107.
Christopher W. Stackpole Laura Groszek Suraj S. Kalbag 《Clinical & experimental metastasis》1995,13(2):105-115
Four mouse B16 melanoma subclones (G3.15, G3.5, G3.12 and G3.26) exhibit progressively greater growth capacity in vitro and in vivo. Previously, non-metastatic G3.15 cells were sequentially converted, in monolayer cultures, to the moderately-metastatic G3.5 cells, and then to a highly-metastatic G3.5* phenotype. Both conversions were induced by hypoxia followed by confluence, and also occurred in tumors. G3.5* cells were comparable with, yet distinguishable from, G3.12 cells in being growth-autonomous in culture. In this study, the presumption that rapidly-growing G3.26 cells represented the ultimate progression step in this clonal system was examined. Both G3.12 and G3.5* cells converted in vitro to the G3.26 phenotype during growth in serum-free medium conditioned by G3.26 cell growth. By selective filtration of conditioned medium and characterization of the stability of growth- and conversion-promoting activities, three distinct activities were found to promote a two-step G3.12 to G3.26 phenotype conversion: (1) a < 10 kDa filtrate stimulated slight attachment and proliferation of G3.12 cells, effects that were reversible, partly attributable to accumulated lactate, and fully mimicked by medium acidification to pH 6.5; (2) medium acidification, together with a heat- and acid-stable but partially trypsin-sensitive > 10 kDa activity, induced G3.12 G3.5* conversion that resulted in acquisition of growth autonomy; and (3) a heat-, acid- and trypsin-sensitive > l0 kDa activity induced G3.5* G3.26 conversion, characterized by anchorage-independent growth in soft agar, and potent lung colonization following intravenous injection. Phenotype analysis of G3.12 tumors and lung metastases revealed that G3.5*-like cells were regularly present in tumors and metastases, whereas G3.26-like cells occurred almost exclusively in large lung metastases. While G3.12 cells might convert to G3.5* cells in order to disseminate, G3.26 cells are apparently not involved in metastatic spread but probably account for the rapid growth of established metastases. 相似文献
108.
The OPAR mouse monoclonal antibody (mAb) directed against rat hepatocytes was previously shown to inhibit adhesion of TA3/Ha mammary carcinoma cells to hepatocytes. The antigen is abundantly present at the surface of hepatocytes beneath the endothelium of liver capillaries where we have observed invasion of carcinoma cells to occur. The OPAR mAb reacted with three major bands on a Western blot of liver plasma membrane proteins. The same proteins were also seen upon immunoprecipitation from iodinated liver plasma membrane proteins. We have isolated OPAR antigens by lectin wheat germ agglutinin (WGA) and OPAR affinity chromatography. Amino acid sequence analysis revealed that two of the bands were 1-macroglobulin and C4-binding protein, which are serum components produced by hepatocytes. The presence of the epitope on distinct proteins and our previous observation that it can be detected in the Golgi apparatus but not in the endoplasmic reticulum, suggested that OPAR reacts with a liver-specific glycoconjugate. Loss of OPAR reactivity after neuraminidase and N-glycosidase F treatment showed that the epitope contains sialic acid residues on N-linked sugar moieties. OPAR also reacted with rat fibronectin, and inhibited adhesion of TA3/St cells to fibronectin. This explains the inhibition by the OPAR mAb of TA3/St cell adhesion to hepatocytes, which we have shown to be due mainly to interaction with hepatocyte surface-associated fibronectin. However, adhesion of the related TA3/Ha cells to hepatocytes, which is mediated by the 6P4 integrin, and does not involve binding to fibronectin, is also inhibited. This suggests that 64 on liver-metastasizing carcinoma cells binds to an OPAR epitope-carrying glycoprotein produced by hepatocytes. 相似文献
109.
110.
目的:分析舌鳞癌颈淋巴结转移的发生规律,探讨舌癌特别是 cNo(临床不怀疑转移)患者的治疗原则。 方法: 通过对1985-2003年199例舌癌患者进行舌颌颈联合根治术的临床病理资料进行回顾性研究。 结果: 舌鳞癌的总体转移率为42.14%,cNo患者的颈淋巴结隐匿性转移率为26.83%,舌鳞癌的隐匿性转移与肿瘤TNM分期等密切相关。 结论: 临床上应根据原发灶的大小等综合考虑分析,选择合理的治疗方案。 相似文献