全文获取类型
收费全文 | 5979篇 |
免费 | 576篇 |
国内免费 | 275篇 |
专业分类
耳鼻咽喉 | 49篇 |
儿科学 | 82篇 |
妇产科学 | 97篇 |
基础医学 | 855篇 |
口腔科学 | 81篇 |
临床医学 | 716篇 |
内科学 | 937篇 |
皮肤病学 | 33篇 |
神经病学 | 412篇 |
特种医学 | 146篇 |
外国民族医学 | 1篇 |
外科学 | 695篇 |
综合类 | 864篇 |
现状与发展 | 2篇 |
预防医学 | 392篇 |
眼科学 | 132篇 |
药学 | 647篇 |
5篇 | |
中国医学 | 236篇 |
肿瘤学 | 448篇 |
出版年
2024年 | 16篇 |
2023年 | 74篇 |
2022年 | 165篇 |
2021年 | 283篇 |
2020年 | 189篇 |
2019年 | 178篇 |
2018年 | 181篇 |
2017年 | 159篇 |
2016年 | 149篇 |
2015年 | 228篇 |
2014年 | 303篇 |
2013年 | 282篇 |
2012年 | 417篇 |
2011年 | 467篇 |
2010年 | 249篇 |
2009年 | 197篇 |
2008年 | 320篇 |
2007年 | 301篇 |
2006年 | 305篇 |
2005年 | 319篇 |
2004年 | 257篇 |
2003年 | 202篇 |
2002年 | 176篇 |
2001年 | 172篇 |
2000年 | 186篇 |
1999年 | 184篇 |
1998年 | 113篇 |
1997年 | 103篇 |
1996年 | 72篇 |
1995年 | 62篇 |
1994年 | 59篇 |
1993年 | 44篇 |
1992年 | 86篇 |
1991年 | 63篇 |
1990年 | 35篇 |
1989年 | 47篇 |
1988年 | 42篇 |
1987年 | 30篇 |
1986年 | 20篇 |
1985年 | 20篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 11篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1975年 | 5篇 |
1969年 | 2篇 |
1967年 | 2篇 |
排序方式: 共有6830条查询结果,搜索用时 31 毫秒
11.
Antiproliferative Activity Against MCF‐7 Breast Cancer Cells by Diamino‐Triazaspirodiene Antifolates
Xiang Ma Renee Ser‐Peng Woon Paul Chi‐Lui Ho Wai‐Keung Chui 《Chemical biology & drug design》2009,74(3):322-326
Two triazaspirodienes, having similar phenoxy propyloxy side chain, were identified as potent mammalian dihydrofolate reductase inhibitors; one having a 6,5‐spiro bicyclic ring system (IC50 = 2.3 nm ) and the other a 6,6‐spiro bicyclic system (IC50 = 6.9 nm ). They also showed more than 50% antiproliferative activity against the MCF‐7 breast cancer cells at 20 μm . This study demonstrated the potential lead of the diamino‐triazaspirodienes in anticancer chemotherapeutical agents’ discovery. 相似文献
12.
Deborah A Cahn-Weiner Sarah Tomaszewski Farias Laura Julian Danielle J Harvey Joel H Kramer Bruce R Reed Dan Mungas Margaret Wetzel Helena Chui 《Journal of the International Neuropsychological Society》2007,13(5):747-757
Impaired ability to conduct daily activities is a diagnostic criterion for dementia and a determinant of healthcare services utilization and caregiver burden. What predicts decline in instrumental activities of daily living (IADLs) is not well understood. This study examined measures of episodic memory, executive function, and MRI brain volumes in relation to baseline IADLs and as predictors of rate of IADL change. Participants were 124 elderly persons with cognitive function between normal and moderate dementia both with and without significant small vessel cerebrovascular disease. Random effects modeling showed that baseline memory and executive function (EXEC) were associated with baseline IADL scores, but only EXEC was independently associated with rate of change in IADLs. Whereas hippocampal and cortical gray matter volumes were significantly associated with baseline IADL scores, only hippocampal volume was associated with IADL change. In a model including cognitive and neuroimaging predictors, only EXEC independently predicted rate of decline in IADL scores. These findings indicate that greater executive dysfunction at initial assessment is associated with more rapid decline in IADLs. Perhaps executive function is particularly important with respect to maintaining IADLs. Alternatively, executive dysfunction may be a sentinel event indicating widespread cortical involvement and poor prognosis. 相似文献
13.
Lesbianism in China has a long but usually hidden history. This paper examines the historical and literary sources of the past to illustrate the history of lesbianism and then turns to a survey of lesbianism in the China of today. As in the past, lesbianism remains more or less hidden, and comes to light only occasionally. Data for contemporary China comes from a visit to an institution for delinquent young women, recent police records, and contemporary fiction. It has only been in the past 4 or 5 years that it was possible to talk about lesbianism and most lesbians are fearful of becoming identified. 相似文献
14.
We describe a novel alpha-thalassaemia-1 deletion that removes the entire zeta-alpha globin gene cluster. A Chinese couple were referred for counselling after two consecutive pregnancies ended with fetal hydrops. Gene mapping was used to demonstrate that the mother is heterozygous for the South-east Asia alpha-thalassaemia-1 deletion (zeta zeta zeta alpha alpha/zeta zeta--SEA), while the father carries an alpha-thalassaemia-1 deletion of more than 100 kilobases (zeta zeta alpha alpha/----). This newly discovered deletion extends for unknown distances 3' and 5' of the zeta-alpha globin gene cluster and has been designated (--HW). 相似文献
15.
16.
The metabolic disposition of 14C-labeled 4-chlorodiphenyl ether ([14C]4-CDE) was examined in rats following iv administration of a single dose (850 nmol/kg). [14C]4-CDE decayed rapidly from the blood since no unchanged [14C]4-CDE was detected in the blood beyond 2 hr after [14C]4-CDE administration. The dispositional kinetics of [14C]4-CDE in rats were best described by a two-compartment open pharmacokinetic model. Total radioactivity was excreted slowly from rats; about 41% and 33% of the administered dose were excreted into the urine and feces, respectively, within 1 week after chemical administration. About 5% of the total radioactivity administered to rats was excreted into the bile in 1 hr. The bulk of the radioactivity in the excreta was due to the presence of [14C]4-CDE metabolites. 14C-labeled 4'-hydroxy-4-CDE was the major metabolite and accounted for at least 90% of the radioactivity in the urine. The metabolic conversion of [14C]4-CDE to 14C-labeled 4'-hydroxy-4-CDE was corroborated by in vitro studies with liver microsomes of rats. In addition, [14C]4-CDE was converted by liver microsomes to reactive metabolites which bound irreversibly to microsomal protein. An arene oxide is suggested as the intermediate metabolite in the biotransformation of [14C]4-CDE by rats. 相似文献
17.
18.
高等护理毕业生应具备临床护理、护理教育、护理科研、护理管理、社区护理5方面的能力。其授课水平的高低将成为评价高护生护理教育能力的重要指标。我院从2002年起探讨对高护生临床授课的教学模式,以提高授课水平。笔者对2004年-2005年在我院实习的168名高护生进行调查,现将结果报告如下。 相似文献
19.
Mast cells in adenoid liver tumors of 32 rats induced with nitrosomorpholine were observed ultrastructurally, and among them, some were studied immunocytochemically via immunogold techniques. Data indicating that mast cells which located in tumor tissues presented positive expression of rat mast cell protein (RMCP) Ⅰ, Indicating origination from the mucosa mast cells, while those in the connective tissues around tumors were largely stained negatively with either RMCP Ⅰor RMCP Ⅰ antisera, with the exception of only a few cells showing positive RMCP Ⅰ staining. Ultrastructural observation showed that mast cells in tumon contacted closely with the tumor cells. Membranes of the intracytoplasmic granules in these mast cells were fusing together. The content inside the granules were discharged and spread along the intercellular space between the tumor cells. There was not any lesion observed uitrasructrually in the tumor cells contacting with the mast cells. The significance of mucosa mast cells in adenoi 相似文献
20.
为探讨四君子汤对烧伤早期代谢营养的作用,采用30%Ⅲ度烧伤豚鼠胃造口模型将400g左右豚鼠分别在喂养等量热卡、氮和自由进食两种膳食条件下,将31只豚鼠分为四组,即喂养治疗组(n=7),喂养对照组(n=4),自食治疗组(n=9),自食对照组(n=11)予以观察。结果发现:自由进食时,四君子汤能增加摄食量,减轻伤后体重丢失,改善氮平衡,增加肝、回肠粘膜含氮量,而躯壳重及腓肠肌含氮量增加不明显,但静息代谢率则增加;等量喂养时,四君子汤治疗组体重、躯壳重及腓肠肌含氮量显著低于对照组,而肝、肠粘膜重量及含氮量差异无显著意义。此外,四君子汤还可调整激素和内脏组织含水量。因此,我们认为四君子汤对改善烧伤后代谢营养及脏器功能可能是有益的 相似文献