全文获取类型
收费全文 | 231558篇 |
免费 | 11229篇 |
国内免费 | 928篇 |
专业分类
耳鼻咽喉 | 2973篇 |
儿科学 | 7340篇 |
妇产科学 | 5117篇 |
基础医学 | 32117篇 |
口腔科学 | 8013篇 |
临床医学 | 17248篇 |
内科学 | 55079篇 |
皮肤病学 | 6592篇 |
神经病学 | 20478篇 |
特种医学 | 5401篇 |
外国民族医学 | 4篇 |
外科学 | 25289篇 |
综合类 | 1043篇 |
一般理论 | 81篇 |
预防医学 | 22353篇 |
眼科学 | 4530篇 |
药学 | 15929篇 |
中国医学 | 1020篇 |
肿瘤学 | 13108篇 |
出版年
2024年 | 474篇 |
2023年 | 1773篇 |
2022年 | 2761篇 |
2021年 | 6160篇 |
2020年 | 3591篇 |
2019年 | 5937篇 |
2018年 | 8321篇 |
2017年 | 5441篇 |
2016年 | 5654篇 |
2015年 | 6253篇 |
2014年 | 7729篇 |
2013年 | 10820篇 |
2012年 | 17566篇 |
2011年 | 18531篇 |
2010年 | 9720篇 |
2009年 | 7601篇 |
2008年 | 14849篇 |
2007年 | 15396篇 |
2006年 | 14233篇 |
2005年 | 13731篇 |
2004年 | 12311篇 |
2003年 | 11292篇 |
2002年 | 10410篇 |
2001年 | 4453篇 |
2000年 | 4944篇 |
1999年 | 3977篇 |
1998年 | 1317篇 |
1997年 | 965篇 |
1996年 | 875篇 |
1995年 | 708篇 |
1994年 | 624篇 |
1993年 | 539篇 |
1992年 | 1598篇 |
1991年 | 1286篇 |
1990年 | 1158篇 |
1989年 | 977篇 |
1988年 | 831篇 |
1987年 | 799篇 |
1986年 | 802篇 |
1985年 | 661篇 |
1984年 | 536篇 |
1983年 | 447篇 |
1979年 | 419篇 |
1975年 | 330篇 |
1974年 | 376篇 |
1973年 | 389篇 |
1972年 | 317篇 |
1971年 | 337篇 |
1970年 | 319篇 |
1969年 | 327篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
21.
Caterina Proto Daniela Romualdi Rosa Maria Cento Rosario S Spada Giuseppina Di Mento Raffaele Ferri Antonio Lanzone 《Gynecological endocrinology》2006,22(4):213-218
BACKGROUND: In the central nervous system, several neuropeptides are believed to be involved in the pathophysiology of Alzheimer's disease (AD). Indeed, previous studies have documented that glucagon-like peptide 1 (GLP-1) possesses neurotropic properties and can reduce amyloid-beta peptide levels in the brain in vivo. Moreover, the concentrations of neuropeptide Y (NPY) seem to be altered in the cerebrospinal fluid of patients with AD and in subjects with major depression. Finally, among the modifications induced by aging, a dysregulation of the ghrelin-growth hormone (GH) system has been reported. METHODS: We investigated the plasma concentrations of these neuropeptides in 14 subjects with AD. Data obtained from these patients were compared with data from an age- and weight-matched healthy group. RESULTS: No significant differences were found between the two groups in relation to plasma levels of GLP-1, NPY, ghrelin and GH. Peripheral NPY concentrations were positively correlated with ghrelin levels in both groups, and with plasma GLP-1 concentration only in controls. CONCLUSION: On the basis of our results, peripheral levels of these neuropeptides seem not to serve as biochemical markers of AD. 相似文献
22.
Jorge Guardado Carlos Cotrim Otília Sim?es Sofia Almeida Mário Ialá Luís Lopes Hélder Pereira Manuel Carrageta 《Revista portuguesa de cardiologia》2006,25(4):409-415
INTRODUCTION: Transesophageal echocardiography (TEE) has become increasingly useful in the study of patients with suspected pulmonary thromboembolism. OBJECTIVE: The aim of this study was to prospectively evaluate the usefulness of TEE in the study of the distal part of the left pulmonary artery (LPA) as well as the influence of this procedure on total echocardiographic exam duration. METHODOLOGY: A prospective study in two groups of consecutive patients referred for TEE with a one- year interval between evaluation of Group A: 33 patients, 17 male, mean age 54 +/- 24 years, and Group B: 42 patients, 20 male, mean age 48 +/- 27 years (p = NS). The procedure was considered long when it took more than 3 min to evaluate the distal part of the LPA. RESULTS: In group A we were able to visualize the distal part of the LPA in 24 patients (73%) without significant prolongation of total exam duration in 16 patients (48% of group A). In one of the patients with suspected pulmonary thromboembolism thrombi were only observed in the distal part of the LPA. In group B we were able to visualize the distal part of the LPA in 36 patients (86%) without significant prolongation of total exam duration in 26 patients (61% of group B). CONCLUSIONS: 1. Visualization of the distal part of the LPA was possible in more patients, and with TEE time prolongation in less patients, in group B. These differences can be accounted for by the training of the operator in this technique. 2. The importance of visualization of this part of the LPA in guiding treatment in the subset of patients with pulmonary thromboembolism confirms the usefulness of this specific procedure. 相似文献
23.
24.
25.
26.
The present authors investigated the excretion, distribution and pharmacokinetics of the novel potential antirheumatic agent flobufen and its active metabolite after p.o. and i.v. doses of 2, 10 and 50 mg/kg administered to rats. The drug is resorbed well from the digestive tract and mostly it is metabolized to the principal metabolite M, which is only slowly excreted from the organism mainly by renal clearance. Within the whole dose range the kinetics of the drug is linear. Binding of flobufen and M to proteins is high (95-99%). The highest concentrations of radioactive metabolites (mostly M) were found in the plasma, liver, lungs, kidneys, connective tissue and inflammatory foci. The penetration of metabolites through the placenta and excretion in human milk are relatively important. 相似文献
27.
28.
29.
30.