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   132篇
  免费   4篇
  国内免费   105篇
耳鼻咽喉   1篇
儿科学   1篇
妇产科学   5篇
基础医学   3篇
口腔科学   3篇
临床医学   67篇
内科学   19篇
神经病学   7篇
特种医学   1篇
外科学   18篇
综合类   28篇
预防医学   2篇
眼科学   5篇
药学   78篇
肿瘤学   3篇
  2022年   1篇
  2021年   3篇
  2019年   3篇
  2018年   2篇
  2017年   2篇
  2016年   5篇
  2015年   3篇
  2014年   4篇
  2013年   3篇
  2012年   7篇
  2011年   9篇
  2010年   2篇
  2009年   2篇
  2008年   6篇
  2007年   63篇
  2006年   8篇
  2005年   16篇
  2004年   1篇
  2002年   7篇
  2001年   12篇
  2000年   5篇
  1999年   3篇
  1998年   8篇
  1997年   6篇
  1996年   2篇
  1995年   2篇
  1994年   4篇
  1993年   8篇
  1992年   15篇
  1991年   3篇
  1990年   7篇
  1989年   7篇
  1988年   10篇
  1987年   1篇
  1984年   1篇
排序方式: 共有241条查询结果,搜索用时 46 毫秒
1.
This molecular epidemiologic case-control study of lung cancer incorporated three complementary biomarkers: the glutathione S- transferase M1 (GSTM1) null genotype, a potential marker of susceptibility, and polycyclic aromatic hydrocarbon-DNA adducts (PAH- DNA) and sister chromatid exchanges (SCE), both indicators of environmentally induced genetic damage. Associations between biomarkers and lung cancer were investigated, as were possible gene-environment interactions between the GSTM1 null genotype and tobacco smoke exposure. Subjects included 136 primary non-small cell lung cancer surgical patients and 115 controls at the Columbia Presbyterian Medical Center. Questionnaire and Tumor Registry data, pre-treatment blood samples and biomarker measurements on blood were obtained. Overall, GSTM1 null genotype was significantly associated with lung cancer [odds ratio (OR) = 2.04, 95% confidence interval (CI) = 1.13-3.68]. ORs for GSTM1 and lung cancer were significant in females (2.50, 1.09-5.72) and smokers (2.25, 1.11-4.54) and not significant in males (1.4, 0.58-3.38) and non-smokers (0.88, 0.18-4.33). However, ORs for males versus females and smokers versus non-smokers did not differ significantly. The OR for GSTM1 and lung cancer in female smokers was 3.03 (1.09- 8.40), compared with 1.42 (0.53-4.06) in male smokers. In contrast to PAH-DNA adducts in leukocytes, SCE did not differ between cases and controls. Neither biomarker differed significantly between the two GSTM1 genotypes. The combined effect of elevated PAH-DNA adducts and GSTM1 genotype on case-control status (16.19, 1.2-115) appeared multiplicative. Results suggest that the effect of the GSTM1 null genotype is greatest in female smokers, which is consistent with other evidence that indicates that women are at higher risk of lung cancer than males, given equal smoking. Persons with both the GSTM1 deletion and elevated PAH-DNA adducts may represent a sensitive subpopulation with respect to carcinogens in tobacco smoke and other environmental media.   相似文献   
2.
N,N-Substituted benzimidazole salts were successfully synthesized and characterized by 1H-NMR, 13C {1H} NMR and IR techniques, which support the proposed structures. Catalysts generated in situ were efficiently used for the carbonylative cross-coupling reaction of 2 bromopyridine with various boronic acids. The reaction was carried out in THF at 110 °C in the presence of K2CO3 under inert conditions and yields unsymmetrical arylpyridine ketones. All N,N-substituted benzimidazole salts 2a–i and 4a–i studied in this work were screened for their cytotoxic activities against human cancer cell lines such us MDA-MB-231, MCF-7 and T47D. The N,N-substituted benzimidazoles 2e and 2f exhibited the most cytotoxic effect with promising cytotoxic activity with IC50 values of 4.45 μg mL−1 against MDA-MB-231 and 4.85 μg mL−1 against MCF7 respectively.

The in situ prepared four component system Pd(OAc)2, 1,3-dialkylbenzimidazolium halides 2a–i and 4a–i, K2CO3 under CO atmosphere catalyses carbonylative cross-coupling reaction of 2-bromopyridine with various boronic acids to yield unsymmetrical arylpyridine ketones.  相似文献   
3.
原发性胆汁性肝硬化自身抗体谱研究进展   总被引:4,自引:1,他引:4  
原发性胆汁性肝硬化(primary biliary cirrhosis, PBC)是一种慢性渐进性胆汁淤积性肝脏疾病, 以小胆管破坏为主要组织学特征的非化脓性炎症,并以血清中出现特征性自身抗体为主要标志.自身抗体对该病发病机制、诊断、治疗及预后均有重要意义.我们就PBC自身抗体谱研究进展作简要综述.  相似文献   
4.
CD4 CD25 调节性T细胞是维持机体自身免疫耐受的调节性T细胞亚群,主要来源于胸腺, 与自身免疫性疾病的发生、发展密切相关.炎症性肠病(IBD)是一种病因未明侵犯胃肠道的自身免疫性疾病,免疫耐受异常是导致其发病主要因素之一.CD4 CD25 调节性T细胞的异常表达可能与IBD的发病有关.  相似文献   
5.
Objective To explore the characteristics of arrhythmogenic right ventricular cardiomyopathy (ARVC). Methods Seven patients with arrhythmogenic right ventricular cardiomyopathy and 34 members of three families were studied. All patients and family members underwent history collection, clinical examination, electrocardiogram (ECG), two-dimensional echocardiography (2-DE) and a signal averaging electrocardiogram. Programmed ventricular stimulation was performed in five patients. Results All patients and family members had normal morphologic characteristics and normal function of the left ventricular by 2-DE. Fourteen persons had abnormal findings indicating ARVC. Five had enlargement of the right ventricular with diffused hypocontractility, eight had thin and systolic bulging in the focal anterior wall with hypokinesia and one had bulging of the inferior wall. Twenty-five persons (seven patients and 18 family members) had abnormal findings in ECG. Positive ventricular late potential was recorded in 13 persons (six patients). Two to three monomorphic ventricular tachycardia (VT) with left bundle branch block (LBBB) configurations were induced in five patients. Ventricular fibrillation was induced in two patients during the electrophysiologic study (EPS). Five patients had very high pacing threshold and/or ineffective pacing in one or many regions of the right ventricle. Two members of one family died suddenly. One member was a dwarf with ARVC. Spontaneous VT with a left bundle branch block (LBBB) configuration was recorded in five patients, polymorphic VT with extremely short coupling interval in one, and premature ventricular complexes with LBBB configuration in 12 (six patients). Conclusion Our familial study strongly suggests that ARVC may be a hereditary disease and it is helpful in the diagnosis and detection of ARVC. The most common manifestations were abnormal structure and function of the right ventricle and abnormal ECG of repolarization and ventricular arrhythmia which originates from the right ventricle.  相似文献   
6.
0 引言 手术切除椎管内肿瘤是唯一有效的治疗方法 .由于病变部位的特殊性 ,手术难度大、危险性大 ,术后易出现神经损伤、脊髓缺血、水肿 ,发生呼吸障碍、高热、消化道出血、四肢瘫痪或截瘫等严重并发症 .其护理工作也具有一定的复杂性和特殊性 .1 临床资料 我院 2 0 0 0 - 0 5 / 11收治椎管内肿瘤患者 2 6 (男19,女 7)例 ,年龄 9~ 6 1岁 .颈椎段 14例 ,胸椎段 6例 ,腰椎段 5例 ,骶管内 1例 . 7例为转移瘤 ,2例为原发性胶质瘤 ,其余均为良性肿瘤 .本组患者以颈段椎管内肿瘤居多 (5 4% ) .2 讨论 为使患者安全渡过围手术期 ,术前健康教…  相似文献   
7.
1 临床资料我们总结2004-02/2004-06在第四军医大学唐都医院神经外科住院行栓塞治疗颅内动脉瘤患者27(男12,女15)例,年龄32~72岁.  相似文献   
8.
9.
青翘和老翘中连翘苷的含量测定   总被引:10,自引:0,他引:10  
目的:测定青翘与老翘中连翘苷含量。方法:。双波和薄层扫描法。结果:表翘中连翘苷含量为0.076%;老翘中仅占0.012%,与报道的青翘中连翘酯苷含量高于老翘的实验结果相同,结论;本文结果与文献报道的就抗菌效价而言青翘优于老翘的结论吻合,目前市售药材青老翘混杂,有必要进行深入研究,确定合理的采收期。  相似文献   
10.
目的 :寻找具有正性肌力活性的化合物。方法 :根据文献报道的二氢喹啉酮类正性肌力药物的结构特点 ,设计、合成了其类似物。以苯胺为起始原料经多步合成 ,对所得化合物用离体豚鼠心脏与主动脉观察了心肌收缩力、扩血管作用及心率。结果 :合成了 1 0个 6 ( 4 酰基 1 哌嗪乙酰氨基 ) 3 ,4 二氢 2 ( 1H) 喹啉酮类化合物 ( 4a~ 4j) ,均为未见文献报道的化合物。结论 :初步药理试验表明 ,化合物 ( 4h)显示了正性肌力及扩血管活性。  相似文献   
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