全文获取类型
收费全文 | 58522篇 |
免费 | 5413篇 |
国内免费 | 4145篇 |
专业分类
耳鼻咽喉 | 650篇 |
儿科学 | 599篇 |
妇产科学 | 564篇 |
基础医学 | 6006篇 |
口腔科学 | 872篇 |
临床医学 | 7424篇 |
内科学 | 7935篇 |
皮肤病学 | 569篇 |
神经病学 | 2778篇 |
特种医学 | 2278篇 |
外国民族医学 | 36篇 |
外科学 | 6354篇 |
综合类 | 10808篇 |
现状与发展 | 13篇 |
一般理论 | 3篇 |
预防医学 | 4151篇 |
眼科学 | 1623篇 |
药学 | 6338篇 |
53篇 | |
中国医学 | 4150篇 |
肿瘤学 | 4876篇 |
出版年
2024年 | 251篇 |
2023年 | 854篇 |
2022年 | 2312篇 |
2021年 | 2939篇 |
2020年 | 2394篇 |
2019年 | 1872篇 |
2018年 | 2009篇 |
2017年 | 1996篇 |
2016年 | 1800篇 |
2015年 | 2880篇 |
2014年 | 3615篇 |
2013年 | 3327篇 |
2012年 | 4839篇 |
2011年 | 5180篇 |
2010年 | 3593篇 |
2009年 | 2913篇 |
2008年 | 3372篇 |
2007年 | 3121篇 |
2006年 | 3044篇 |
2005年 | 2810篇 |
2004年 | 1833篇 |
2003年 | 1736篇 |
2002年 | 1439篇 |
2001年 | 1186篇 |
2000年 | 1113篇 |
1999年 | 1053篇 |
1998年 | 655篇 |
1997年 | 587篇 |
1996年 | 485篇 |
1995年 | 454篇 |
1994年 | 344篇 |
1993年 | 259篇 |
1992年 | 315篇 |
1991年 | 307篇 |
1990年 | 210篇 |
1989年 | 163篇 |
1988年 | 184篇 |
1987年 | 154篇 |
1986年 | 101篇 |
1985年 | 80篇 |
1984年 | 61篇 |
1983年 | 32篇 |
1982年 | 29篇 |
1981年 | 31篇 |
1980年 | 23篇 |
1979年 | 38篇 |
1978年 | 13篇 |
1977年 | 11篇 |
1975年 | 11篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
Jing‐Long Huang Liang‐Shiou Ou Ching‐Hsiung Tsao Li‐Chen Chen Ming‐Ling Kuo 《Pediatric allergy and immunology》2002,13(6):426-433
T lymphocytes play a fundamental role in the initiation and regulation of chronic inflammatory responses in patients with asthma. CD69 is an early marker of T‐cell activation. The levels of intercellular adhesion molecule‐1 (ICAM‐1, CD54) and L ‐selectin have been reported to increase in patients with allergic diseases and asthma. The present study was therefore undertaken to investigate the expression of CD69, CD54, and L ‐selectin by T lymphocytes of children with asthma, before and after immunotherapy. Eighteen children newly diagnosed with asthma, 11 good and nine poor responders to immunotherapy, and 16 normal subjects, were enrolled in this study. The percentages of CD69+, CD54+, and CD62L+ cells in T lymphocytes were measured by using flow cytometry. The levels of CD69, CD54, and CD62L in serum and culture supernatants were determined by using enzyme‐linked immunosorbent assay (ELISA). The expression of CD69 and CD54 on CD3+ T lymphocytes was significantly higher in children with asthma than in control patients. All the patient groups expressed (spontaneously and following stimulation with phorbol myristate acetate and ionomycin together with mite‐extract proteins) greater amounts of CD69 and CD54 than did control subjects. With long‐term immunotherapy, the percentages of CD69+ and CD54+ T lymphocytes were significantly lower in patients with a good response to immunotherapy. Our results also showed significantly lower serum L ‐selectin levels following immunotherapy. In conclusion, successful immunotherapy resulted in decreased expression and production of CD69 and CD54. These results may explain, in part, the clinical efficacy of immunotherapy. 相似文献
12.
13.
14.
Mixed disulfide between lens crystallin and glutathione has been observed in human cataracts and could be formed in vitro by thiol-disulfide exchange reaction. The glutathionyl crystallins have been reported to become partially unfolded. The present paper reports the conformational destabilization by the mixed disulfide formation in calf alpha- and gamma-II crystallin. The conformational stability was studied by the denaturants urea and guanidine hydrochloride (Gdn-HCl), and by proteolytic degradation. The denaturation curves of both urea and Gdn-HCl shift to lower denaturant concentration for crystallins of glutathione mixed disulfide. The decrease in conformational stability is estimated to be 0.22- and 0.92 kcal mol-1 for modified alpha- and gamma-II crystallin, respectively. Proteolytic digestion also shows a faster rate of degradation for the modified crystallins. These results indicate that mixed disulfide destabilizes the crystallin conformation. The destabilization may make crystallins more susceptible to changes as observed in aging lenses. 相似文献
15.
本文对从事京剧打击乐的55人(110耳)进行了听力调查及动态观察。利用图表进行对比分析,发现110耳中高频听力损伤89耳,占81%;语频听力损伤32耳,占29.1%;其中伴有高频耳鸣78耳,占70.9%。动态观察30人(60耳),均为永久性听阈阈移。高频听力损伤最早出现的频率是4kHz,并见典型“V”谷,符合噪声性聋的诊断。 相似文献
16.
D Johnstone M Limacher M Rousseau C S Liang L Ekelund M Herman D Stewart M Guillotte G Bjerken W Gaasch 《The American journal of cardiology》1992,70(9):894-900
The Studies of Left Ventricular Dysfunction (SOLVD) trials were designed to evaluate the effects of enalapril on long-term mortality in patients with severe left ventricular (LV) dysfunction. Patients with LV ejection fractions less than or equal to 0.35 and symptoms of congestive heart failure (CHF) were enrolled in the treatment trial, whereas those with no history of overt CHF and taking no treatment directed for LV dysfunction were enrolled in the prevention trial. The baseline clinical characteristics of SOLVD patients were compared to characterize differences between patients in these 2 separate but concurrent trials. From over 70,000 patients screened with LV dysfunction, 4,228 patients were enrolled in the prevention trial and 2,569 patients in the treatment trial. Ischemic heart disease was the primary cause of LV dysfunction in both prevention (83%) and treatment (71%) trial patients. Prior myocardial infarction was present in 80% of the prevention and 66% of the treatment trial patients (p less than 0.001). In the prevention trial, infarction was recent (less than or equal to 6 months) in 27% patients and remote (greater than 6 months) in 57% patients. Treatment trial patients had proportionately more women (20 vs 13%; p less than 0.001) and non-Caucasians (20 vs 14%; p less than 0.001), as well as the coexisting risk factors of hypertension (42 vs 37%; p less than 0.001) and diabetes (26 vs 15%; p less than 0.001) than did prevention trial patients. Clinical characteristics of patients in both trials were influenced by the gender and race of enrolled patients. Similarly, coronary artery bypass surgery was performed less often in women and non-Caucasians.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
17.
18.
目的探讨胃黏膜内pH值对胆源性胰腺炎病情预后评估及在决定手术冶疗中应用的价值。方法对确诊的146例胆源性胰腺炎患者经鼻插入胃黏膜二氧化碳张力计(TRIP-NGS导管)测定胃黏膜内pH值,每隔12小时测定一次,并进行APACHEⅡ评分,将2组数据与外科治疗进行相关分析。结果①pH值变化反映胆源性胰腺炎病情发展变化,与器官衰竭数呈负相关;②外科干预治疗与内科治疗比较差异有统计学意义(P〈0.05);③pHI〉7.25与pH〈7.25患者开腹手术病死率和细菌培养阳性率比较差异有统计学意义(P〈0.05)。结论pH值对胆源性胰腺炎外科治疗有指导意义。外科处理原则是:①胆道无梗阻,以内科保守治疗为主;②伴胆道梗阻,先行经内镜十二指肠乳头括约肌切开术、经内镜鼻胆管引流术、B超导引引流、腹腔灌洗等,如胆道引流不畅或pH值持续下降,则开腹手术。 相似文献
19.
Liang Ying-rui梁英锐Department of Pathology Hunan Medical University Changsha 《中华医学杂志(英文版)》1989,102(1):53-59
The cytoplasm of human bile ductule epithelia was found to be Type V collagen positive, demonstrating that the epithelia were able to generate this type of collagen. The ductules proliferated greatly with Type V collagen positive cytoplasm in piece-meal necrosis of chronic active hepatitis (CAH). The capillary-like bile ductules inside human hepatic lobules were identified. Our findings might explain the mechanism of fibroplasia in CAH. 相似文献
20.