全文获取类型
收费全文 | 109571篇 |
免费 | 10817篇 |
国内免费 | 8341篇 |
专业分类
耳鼻咽喉 | 805篇 |
儿科学 | 1537篇 |
妇产科学 | 1288篇 |
基础医学 | 12883篇 |
口腔科学 | 1933篇 |
临床医学 | 15641篇 |
内科学 | 15990篇 |
皮肤病学 | 944篇 |
神经病学 | 6282篇 |
特种医学 | 3924篇 |
外国民族医学 | 61篇 |
外科学 | 10796篇 |
综合类 | 18363篇 |
现状与发展 | 24篇 |
一般理论 | 16篇 |
预防医学 | 7448篇 |
眼科学 | 3335篇 |
药学 | 11213篇 |
119篇 | |
中国医学 | 6756篇 |
肿瘤学 | 9371篇 |
出版年
2024年 | 382篇 |
2023年 | 1791篇 |
2022年 | 4929篇 |
2021年 | 6092篇 |
2020年 | 4620篇 |
2019年 | 3805篇 |
2018年 | 4141篇 |
2017年 | 3531篇 |
2016年 | 3396篇 |
2015年 | 5146篇 |
2014年 | 6313篇 |
2013年 | 5435篇 |
2012年 | 7954篇 |
2011年 | 9052篇 |
2010年 | 5614篇 |
2009年 | 4389篇 |
2008年 | 5634篇 |
2007年 | 5447篇 |
2006年 | 5626篇 |
2005年 | 5555篇 |
2004年 | 3438篇 |
2003年 | 3310篇 |
2002年 | 2809篇 |
2001年 | 2461篇 |
2000年 | 2450篇 |
1999年 | 2525篇 |
1998年 | 1641篇 |
1997年 | 1567篇 |
1996年 | 1247篇 |
1995年 | 1134篇 |
1994年 | 975篇 |
1993年 | 634篇 |
1992年 | 797篇 |
1991年 | 683篇 |
1990年 | 612篇 |
1989年 | 558篇 |
1988年 | 501篇 |
1987年 | 408篇 |
1986年 | 355篇 |
1985年 | 298篇 |
1984年 | 184篇 |
1983年 | 117篇 |
1982年 | 98篇 |
1981年 | 102篇 |
1980年 | 71篇 |
1979年 | 118篇 |
1974年 | 57篇 |
1973年 | 73篇 |
1972年 | 58篇 |
1971年 | 62篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Prospective survey of investigations in outpatients referred with iron deficiency anaemia. 总被引:8,自引:1,他引:7 下载免费PDF全文
Recent evidence has suggested that colonic neoplasm may be missed in patients presenting with iron deficiency anaemia unless colonic investigations are performed on all patients even when an alternative cause has been found. This study prospectively surveyed 114 consecutive patients referred from family practitioners to an outpatient clinic for the investigation of iron deficiency anaemia to determine the diagnoses contributing to the anaemia, the usefulness of certain clinical features, and the role of colonic and other investigations in obtaining the diagnosis. Upper gastrointestinal lesions contributing to anaemia were identified in 45 patients while colonic lesions were found in 18. Twenty three patients had a non-gastrointestinal cause for anaemia and in 12 patients no cause was found. Only two patients were identified as having colonic neoplasia (a small adenomatous polyp in each case) coexisting with upper gastrointestinal lesions. Symptoms and signs had a sensitivity and specificity of upper gastrointestinal disease of 50% and 83% respectively, and 44% and 80% for colonic disease. Endoscopy had a high yield (42%) and duodenal biopsy identified coeliac disease in three patients (two were aged > 70 years) each of whom had normal folate values. Barium enema had a yield of 13%. All colonic carcinomas occurred in patients > 65 years. The coexistence of colonic cancer or large polyps with an upper gastrointestinal lesion identified at endoscopy was rare in outpatients referred from family practitioners. Clinical symptoms and signs were poor indicators of the investigations that will detect a cause for the anaemia.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
72.
73.
OBJECTIVE: To study the value of serum progesterone in selecting the candidate patients with ectopic pregnancy (EP) for methotrexate (MTX) treatment and in monitoring the effect of the treatment. METHODS: Thirty-seven EP patients who were given single-dose intramuscular injection with 50 mg/m2 MTX were divided into success and failure groups according to the effect of the treatment. The serum progesterone concentrations in these patients were measured and compared between the 2 groups, and the receiver-operator curves (ROC) were used to determine the critical serum progesterone levels for assessing the effect of MTX treatment. The time consumed respectively by serum progesterone and beta-human chorionic gonadotrophin (beta-hCG) decreasing to below normal level was also compared. RESULTS: The serum progesterone concentrations of the success group (7.93+/-2.02 ng/ml) were significantly lower than those of the failure group (14.53+/-1.72 ng/ml, P<0.05). The recommended critical level for assessing the effect of MTX treatment for EP patients was 11 ng/ml according to the ROC, and the time for serum progesterone decreasing to below normal level was significantly less than that for beta-hCG. CONCLUSION: Serum progesterone can be used as an index for selecting candidate EP patients for MTX treatment, and also as a good indicator for assessing the therapeutic effect after treatment. 相似文献
74.
目的 :探讨外周血单个核细胞 (PBMC)内上游信号分子及核因子 κB(NF κB)在烧伤后炎症级联反应中的作用。 方法 :体外检测在烧伤血浆作用下的PBMC内游离Ca2 及NF κB活化的变化 ,观察钙通道阻断药对NF κB活化及IL 6、NO表达水平的调控作用。 结果 :不同时相点的烧伤血浆可使体外PBMC内Ca2 明显增加 ,培养的PBMC核内NF κB的积聚明显增加 ,培养上清中NO和IL 6高表达。应用尼莫通 (Nimodipine)和丹曲林 (Dantrium)对NF κB的活化有调节作用 ,对IL 6和NO亦有下调作用。 结论 :烧伤血浆可使PBMC内信号分子浓度明显增高 ,NF κB过度活化 ,并易位进入细胞核内 ,NF κB介导的促炎性细胞因子和NO过度表达。两种钙通道阻断药有调控细胞内信号转导的作用 ,对烧伤后全身炎症反应综合征 (SIRS)可能有防治作用 相似文献
75.
浅谈基因治疗的现状及其面临的困境 总被引:1,自引:0,他引:1
基因治疗将在未来的疾病治疗中扮演重要的角色,然而这一新颖的技术却面临着诸多问题,本文论述了基因治疗的发展现状及其所面临的技术难题。 相似文献
76.
种植义齿修复的医学伦理问题 总被引:1,自引:1,他引:0
种植义齿是一项新的修复缺失牙方法,本文从医学伦理学的角度出发,探究种植又齿修复过程中应遵循的医德原则,医师高度的责任心、精湛的医术和正确的口腔宣教是保证种植义齿修复成功的关键。 相似文献
77.
78.
79.
本文应用结肠非低张双重对比灌肠造影诊断结肠病变,这是一种简单的方法。本文根据150例的实践径验介绍了技术、病人的准备、有关造影剂的问题和正常所见,并通过具体的病例阐述了结肠非低张双重对比检查的临床应用价值,并指出了本法的不足之处。 相似文献
80.
The measurement of amniotic fluid (AF) acetylcholinesterase isoenzyme (AChEI) is a relatively new method for early diagnosis of open neural tube defects (NTDs). As quantitative methods are of unproven reliability at present, the authors used a high resolving power qualitative method-vertical slab polyaerylamide gel electrophoresis. The benefits of this technique are: simplicity of operation, accuracy, unsophisticated equipment, and easily available reagents. Combined results of 9 NTDs studies revealed that samples from early pregnancy gave more accurate results than those from late pregnancy. 相似文献