首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   43116篇
  免费   4696篇
  国内免费   2783篇
耳鼻咽喉   428篇
儿科学   478篇
妇产科学   405篇
基础医学   4417篇
口腔科学   1008篇
临床医学   5420篇
内科学   5717篇
皮肤病学   600篇
神经病学   2058篇
特种医学   1710篇
外国民族医学   14篇
外科学   4417篇
综合类   8200篇
现状与发展   13篇
一般理论   10篇
预防医学   3362篇
眼科学   892篇
药学   4982篇
  58篇
中国医学   3497篇
肿瘤学   2909篇
  2024年   206篇
  2023年   733篇
  2022年   2049篇
  2021年   2649篇
  2020年   2003篇
  2019年   1544篇
  2018年   1580篇
  2017年   1593篇
  2016年   1448篇
  2015年   2139篇
  2014年   2674篇
  2013年   2694篇
  2012年   3670篇
  2011年   3947篇
  2010年   2723篇
  2009年   2172篇
  2008年   2487篇
  2007年   2317篇
  2006年   2137篇
  2005年   1867篇
  2004年   1395篇
  2003年   1365篇
  2002年   1216篇
  2001年   841篇
  2000年   606篇
  1999年   498篇
  1998年   328篇
  1997年   245篇
  1996年   199篇
  1995年   196篇
  1994年   168篇
  1993年   118篇
  1992年   120篇
  1991年   105篇
  1990年   85篇
  1989年   81篇
  1988年   62篇
  1987年   72篇
  1986年   55篇
  1985年   45篇
  1984年   34篇
  1983年   16篇
  1982年   13篇
  1981年   17篇
  1980年   7篇
  1979年   13篇
  1977年   8篇
  1976年   6篇
  1975年   6篇
  1970年   5篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
This study aims to investigate the relationship between the levels of IL-18, IL-10, and MMP-9 and -137G/C polymorphism of interleukin 18 with the risk of in-stent restenosis (ISR). The study population consisted of 68 patients with ISR, 173 in non-ISR group, treated with drug-eluting stent and evaluated by coronary angiography post-procedure and at follow-up, and also 109 without angiographic evidence of coronary artery disease (CAD) which formed a reference control group (non-CAD group). The sequential plasma IL-18, IL-10, and MMP-9 levels were assessed at admission, 24 h, and 2 weeks after percutaneous coronary intervention. The -137G/C polymorphism of IL-18 was genotyped by the ligase detection reaction-polymerase chain reaction. Plasma IL-18 and MMP-9 increased significantly from admission, peaking after 24 h and fall after 2 weeks. Compared with the non-ISR group, the ISR group had higher levels of IL-18 and MMP-9, but IL-10 level was the opposite. The -137GG genotype of IL-18 was significantly higher than of the CG and CC genotypes. A significant higher frequency of -137G allele or GG genotype of IL-18 was observed in patients with ISR group compared with the non-ISR group. There is correlation between the changes of IL-18, IL-10, MMP-9, and ISR. IL-18 promoter -137G/C polymorphism influences IL-18 levels and the susceptibility to ISR, suggesting that IL-18-mediated pathways are causally involved in the process of ISR.  相似文献   
992.
目的 观察大鼠脊髓损伤(SCI)后神经元细胞凋亡和相关调控蛋白Caspase-3表达的时间、空间分布规律。方法 SD大鼠50只,分为假手术组和SCI组,钳夹法建立SCI模型,用结晶紫(CV)染色法、TUNEL法和免疫组织化学方法观察SCI后6h、12h、24h、3d和7d损伤中心到头端0~5.00mm空间范围内脊髓神经细胞存活、凋亡以及相关调控蛋白Caspase-3的表达状况。 结果 CV染色发现,SCI后6h~7d在0~0.50mm空间范围内均未发现存活的神经细胞,在1.00~3.50mm距离内,存活的神经细胞数逐渐增加,4.00mm处达峰值;TUNEL结果发现,SCI后6h~7d在1.05~4.55mm范围内,神经细胞出现凋亡,3d时在2.55mm处,细胞凋亡达高峰,7d时显著减少;免疫组织化学结果发现,SCI后6h~7d在1.10~4.60mm范围内,神经元细胞出现Caspase-3阳性表达,3d在3.10mm处Caspase-3表达达到高峰,7d显著减少。 结论 SCI后,凋亡的神经细胞及其相关调控蛋白Caspase-3的表达有一定的时空分布规律。  相似文献   
993.
Pilocytic astrocytoma (PA) is the most frequent solid neoplasm in childhood. It has a good 5‐year overall survival (90% in childhood and 52% in adults). However, up to 20% of patients experience residual tumor growth, recurrence, and death. Although the main genetic alteration of PAs, including KIAA1549:BRAF fusion, involves chromosome 7q34, we previously found frequent loss in chr9q34.3 locus in a small subset of these tumors. Among the genes present in this locus, EGFL7 is related to poor prognosis in several tumor types. In this study, we aimed to assess EGFL7 expression through immunohistochemistry, and to evaluate its prognostic value in a series of 64 clinically and molecularly well‐characterized pilocytic astrocytomas. We found high expression of EGFL7 in 71.9% of patients. Low EGFL7 expression was associated with older patients, the mean age mainly older than 11 years (P = 0.027). EGFL7 expression was not associated with presence of KIAA1549:BRAF fusion, BRAF mutation, FGFR1 mutation, nor FGFR1 duplication. Moreover, high EGFL7 expression was associated with high FGFR1 (P = 0.037) and 5′‐deoxy‐5′‐methyltioadenosine phosphorylase (MTAP) (P = 0.005) expression, and with unfavorable outcome of patients (P = 0.047). Multivariate analysis revealed low EGFL7 expression related to older patients and high EGFL7 expression related to retained expression of MTAP. In addition, we found a borderline significance of unfavorable outcome and high EGFL7 expression. Finally, EGFL7 expression was not associated with overall or event‐free survival of PA patients. Our findings point to EGFL7 expression as a novel candidate prognostic marker in PA, which should be further investigated.  相似文献   
994.
目的 探讨卵巢核分裂象活跃的富于细胞性纤维瘤的临床病理学特征及鉴别诊断.方法 收集2008至2012年间11例卵巢核分裂象活跃的富于细胞性纤维瘤患者的临床病理资料,光镜观察并进行免疫组织化学EnVision法染色.结果 11例患者发病年龄21~ 65岁,平均46岁.肿瘤最大径6 ~ 16 cm,平均9.8 cm.镜下梭形瘤细胞丰富,交叉成束或旋涡状排列,形态温和,细胞轻至中度异型性,核分裂象(4~20)/10 HPF,平均8.4/10 HPF,无坏死.8例进行了波形蛋白检测,均阳性表达.5例检测了WT-1,均有弥漫或灶性阳性表达.α-inhibin和calretinin在检测的6例中仅有1例弥漫表达.6例检测了Ki-67的阳性指数5%~30%,其中1例约10%,1例核分裂象20/10 HPF的Ki-67阳性指数为30%.此外,细胞角蛋白、AE1/AE3、CD117、CD34、CD99和结蛋白在5例检测病例中均呈阴性.2例行网状纤维染色,显示网状纤维包绕在每个瘤细胞周围.10例随访4 ~ 38个月无复发或进展,1例术后94个月复发后仍存活.结论 在卵巢富于细胞性纤维瘤中,当核分裂象≥4/10 HPF、细胞温和、缺乏显著异型时,诊断为核分裂象活跃的富于细胞性纤维瘤比纤维肉瘤更为恰当.绝大多数病例临床呈良性经过,少数病例可复发,提示它是一种具有低度恶性潜能的肿瘤.  相似文献   
995.
Purpose

It was expected that using a comprehensive scale like the Thought and Language Disorder Scale (TALD) for measurement of FTD would enable assessing its heterogeneity and its associations with cognitive impairment and functionality. This study has aimed to analyze the relationship between formal thought disorder (FTD) and cognitive functions, functionality, and quality of life in schizophrenia.

Methods

This cross-sectional exploratory study included 46 clinical participants meeting the DSM-5 diagnostic criteria for schizophrenia and 35 healthy individuals as the control groups. Data were acquired by means of the Turkish language version of the TALD, the Positive and Negative Syndrome Scale, the Clinical Global Impression Scale, the Functioning Assessment Short Test, the Social Functioning Scale, the World Health Organization Quality of Life Instrument-Short Form, and a neuropsychological test battery on executive functions, working memory, verbal fluency, abstract thinking, and response inhibition. Correlation analyses were conducted to detect significant relationships.

Results

The clinical group scored failures in all cognitive tests. The objective positive FTD was associated with deficits in executive functions and social functioning. The objective negative FTD was associated with poor performance in all cognitive domains, physical quality of life, and social and global functioning. The subjective negative FTD was negatively correlated with psychological quality of life.

Conclusion

This study demonstrated that objective FTD factors reflect different underlying cognitive deficits and correlate with different functioning domains. Significant correlation was determined between subjective negative FTD and psychological quality of life. Given the close relationship of FTD with functioning and quality of life, the FTD-related cognitive deficits should be the key treatment goal in schizophrenia.

  相似文献   
996.
Heat shock protein 70 (Hsp70) has been found to play key roles in tumor immunity due its chaperone function of binding antigenic peptides. Here we report it can also stimulate NK cells in vivo, which is another role in Hsp70s' anti-tumor response. Injecting Hsp70 into mice increased splenic NK cell populations, which may be reason for anti-tumor effect of Hsp70. The Hsp70 14-mer peptide (aa450–463, TRD) was identified as the critical epitope for this stimulatory activity. It was the murine Hsp70 14-mer peptide TRD instead of the corresponding human Hsp70 14-mer peptide TKD that functioned in the mouse experimental model.  相似文献   
997.
Fan  Zhen  Sun  Bing  Lang  Li-qin  Hu  Jie  Hameed  N. U. Farrukh  Wei  Zi-xuan  Zhuang  Qi-yuan  Cai  Jia-jun  Liu  Feng-tao  Mao  Yi-ting  Feng  Rui  Pan  Li 《Neurological sciences》2021,42(6):2353-2361
Neurological Sciences - Exploring the role of amygdala enlargement (AE) in temporal lobe epilepsy (TLE) without ipsilateral mesial temporal sclerosis (MTS) using comprehensive presurgical workup...  相似文献   
998.
Urothelial bladder cancer (UBC) is a heterogeneous type of disease. It is urgent to screen biomarkers of tumour aggressiveness in order to clarify the clinical behaviour and to personalize therapy in UBC patients. Raf kinase inhibitory protein (RKIP) is a metastasis suppressor, and its downregulation is associated with metastatic events in an increasing number of solid tumours. We evaluated the clinical and prognostic significance of RKIP expression in patients with high risk of progression UBC. Using immunohistochemistry, we determined RKIP expression levels in a series of 81 patients with high-grade pT1/pTis or muscle-invasive UBC. Staining of CD31 and D2-40 was used to assess blood and lymphatic vessels, in order to distinguish between blood and lymphatic vessel invasion (LVI). We found that 90 % of pT1/pTis tumours, 94 % of non-muscle invasive papillary tumours and 76 % of the cases without LVI occurrence expressed RKIP in >10 % of cells. In this group, we observed a subgroup of tumours (42 %) in which the tumour centre was significantly more intensely stained than the invasion front. This heterogeneous pattern was observed in 63 % of the cases with LVI. Low RKIP expression was associated with poorer 5-year disease-free and overall survival rates, and remained as an independent prognostic factor for disease-free survival. Loss of RKIP expression may be an important prognostic factor for patients with high risk of progression bladder cancer.  相似文献   
999.
The gastrointestinal distribution of glycinin in pigs at different growth stages was investigated in this study. Fifteen healthy General No. 1 barrows weaned on the 28th day were randomly assigned to three groups with five replicates: five weanling, five growing and five finishing. All pigs received diets with non-soya bean ingredients in non-experimental periods, while the pigs received diets containing 4% purified glycinin in experimental periods. Binding of anti-glycinin antibody was detected using a labelled streptavidin–peroxidase complex method to determine the gastrointestinal distribution of glycinin. The results indicated that there was a significant difference on the gastrointestinal mucosal distribution of glycinin between pigs of different ages. Glycinin in growers was higher than piglets and lower than finishers (P<0.001). The highest content of glycinin was in the distal jejunum and ileum for piglets, and in distal jejunum for growers and finishers (P<0.05).  相似文献   
1000.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号