全文获取类型
收费全文 | 49009篇 |
免费 | 3630篇 |
国内免费 | 988篇 |
专业分类
耳鼻咽喉 | 196篇 |
儿科学 | 436篇 |
妇产科学 | 397篇 |
基础医学 | 2322篇 |
口腔科学 | 382篇 |
临床医学 | 5452篇 |
内科学 | 3480篇 |
皮肤病学 | 556篇 |
神经病学 | 832篇 |
特种医学 | 1254篇 |
外科学 | 2410篇 |
综合类 | 12692篇 |
现状与发展 | 2篇 |
一般理论 | 38篇 |
预防医学 | 16534篇 |
眼科学 | 476篇 |
药学 | 2837篇 |
293篇 | |
中国医学 | 2419篇 |
肿瘤学 | 619篇 |
出版年
2024年 | 157篇 |
2023年 | 735篇 |
2022年 | 1494篇 |
2021年 | 1968篇 |
2020年 | 2282篇 |
2019年 | 1498篇 |
2018年 | 1407篇 |
2017年 | 1399篇 |
2016年 | 1424篇 |
2015年 | 1407篇 |
2014年 | 3504篇 |
2013年 | 3697篇 |
2012年 | 3396篇 |
2011年 | 3734篇 |
2010年 | 3093篇 |
2009年 | 2666篇 |
2008年 | 2932篇 |
2007年 | 2748篇 |
2006年 | 2402篇 |
2005年 | 1962篇 |
2004年 | 1600篇 |
2003年 | 1282篇 |
2002年 | 988篇 |
2001年 | 812篇 |
2000年 | 697篇 |
1999年 | 528篇 |
1998年 | 450篇 |
1997年 | 429篇 |
1996年 | 357篇 |
1995年 | 340篇 |
1994年 | 229篇 |
1993年 | 160篇 |
1992年 | 129篇 |
1991年 | 183篇 |
1990年 | 168篇 |
1989年 | 139篇 |
1988年 | 132篇 |
1987年 | 114篇 |
1986年 | 133篇 |
1985年 | 117篇 |
1984年 | 108篇 |
1983年 | 95篇 |
1982年 | 108篇 |
1981年 | 65篇 |
1980年 | 73篇 |
1979年 | 38篇 |
1978年 | 58篇 |
1977年 | 60篇 |
1976年 | 59篇 |
1975年 | 42篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
论述了关系型数据库的革命性贡献与发展中的矛盾,实现医疗系统中的数据管理功能需要解决的问题,以及对临床数据输入系统的需求。 相似文献
32.
33.
幼兔缺血预处理在心肌保护第二窗期对未成熟心肌Bcl-2基因mRNA表达的影响 总被引:2,自引:1,他引:1
目的 观察幼兔心脏缺血预处理 2 4h对未成熟心肌缺血 /再灌注后Bcl -2mRNA表达的影响 ,探讨未成熟心肌保护第二窗形成的作用机理。方法 18只 3~ 4周龄幼兔 ,随机分为 3组 ,每组 6只 :Ⅰ组 ,正常对照组 ;Ⅱ组 ,缺血 /再灌注损伤组 ;Ⅲ组 ,缺血预处理组。建立活体心脏缺血 /再灌注损伤模型 ,Maclab/8s系统监测左心室发展压 (LVDP)、左室压上升及下降最大速率 (+dp/dtmax,-dp/dtmax)变化 ,原位免疫杂交 (ISH)方法检测心肌细胞内Bcl-2mRNA的表达。结果 缺血再灌注前 ,各组间LVDP、±dp/dtmax无显著性差异 (P >0 .0 5) ;再灌注 1h后 ,Ⅱ组的LVDP、+dp/dtmax和 -dp/dtmax恢复率分别为 (42 .81± 12 .56) %、(3 0 .67± 16.2 2 ) %和 (2 9.49± 10 .13 ) % ;Ⅲ组LVDP、+dp/dtmax及 -dp/dtmax恢复率分别为 (84.15± 13 .56) %、(69.49± 10 .3 6) %和 (58.3 7± 12 .45) % ,两组间有显著性差异 (P <0 .0 1)。Ⅱ组、Ⅲ组Bcl -2mRNA表达阳性细胞面积百分数分别为 (8.3± 2 .5) %、(76.3±13 .5) % ,两组间有显著性差异 (P <0 .0 1)。结论 缺血预处理可上调Bcl -2mRNA表达 ,参与未成熟心肌保护第二窗的形成 ,促进未成熟心肌缺血 /再灌注后心室功能恢复 相似文献
34.
Evren Isci Halil Ibrahim Canter Abdullah Kecik 《European journal of plastic surgery》2007,30(1):45-46
Rabbits are the experimental animals of choice in many studies including flaps, wounds, and topical trials for new pharmacological
agents. Because the topical drugs and other materials used for dressing are irritating to the animal, they tend to remove
dressings, bandages, drapes, insensate flaps, and also topical drugs by scratching, licking, and biting if they are within
the reach of the animal. In this study, we report an easy to prepare, user-friendly, comfortable, and cheap dressing protector
called a dressing shield to prevent these problems. 相似文献
35.
Many epidemiological studies have shown the magnitude and seriousness of mental disorders in developing countries. However, mental health care remains unsatisfactory owing to lack of skilled manpower and many other social and medical priorities. General practitioners and other health personnel can significantly help in extending mental health care provided they receive adequate training during their medical curriculum. With this aim, the Department of Psychiatry at Addis Ababa University runs a 6-week full-time course for undergraduate medical students. Its chief objectives, teaching methods, achievements and shortcomings are discussed in the paper. 相似文献
36.
37.
WEIGUANG ZENG PIERRE-OLIVIER REGAMEY KEITH ROSE YUZHOU WANG ERNST BAYER 《Chemical biology & drug design》1997,49(3):273-279
The use of N, O-bisFmoc-N-(2-hydroxy-4-methoxybenzyl) amino acid derivatives in the synthesis of peptides with difficult sequences has already been described. With these amino acid derivatives the reversible protecting group 2-hydroxy-4-methoxybenzyl (Hmb) for the backbone amide bonds of peptide chains is introduced, and thus the aggregation due to hydrogen-bond interchain association is inhibited. This paper describes the synthesis and use of Fmoc-N-(2-hydroxy-4-methoxybenzyl)amino acid derivatives as an alternative means of introducing Hmb backbone protection. These new monoFmoc derivatives were obtained in higher yield than the bisFmoc derivatives. Coupling yields to the amino peptide resin were the same as those obtained with bisFmoc derivatives, under the TBTU/HOBt/DIEA conditions. We also compared different syntheses of a difficult peptide with the Fmoc approach [triple coupling, capping, use of chaotropic agents, backbone protection using monoFmoc (Hmb)Ala] and with optimized Boc chemistry. Both the backbone protection and optimized Boc chemistry approaches gave the desired product in excellent yield and purity. © Munksgaard 1997. 相似文献
38.
RACHEL PHILOSOF-OPPENHEIMER ISRAEL PECHT MATI FRIDKIN 《Chemical biology & drug design》1995,45(2):116-121
The facile thiolytic cleavage of the O-2,4-dinitrophenyl (Dnp) tyrosine bond was applied to the solid-phase synthesis of the 22-amino acid residue peptide H-Asp-Ala-Val-Tyr -Thr-Gly-Leu-Asn-Thr-Arg-Asn-Gln-Glu-Thr-Tyr -Glu-Thr-Leu-Lys-His-Glu-Lys-OH, corresponding to positions 62-83 in the chain of the type 1 receptor for Fcε, domains expressed on the rat mucosal-type mast cells (line RBL-2H3). A method for the spectrophotometric determination of insoluble O-Dnp as well as of unprotected phenolic moieties of tyrosine was developed. It is based on monitoring S-Dnp-2-mercaptoethanol, produced upon O-Dnp thiolysis by 2-mercaptoethanol. © Munksgaard 1995. Dedicated to the memory of Dr. Susumu Funakoshi, a dear friend and a leader in peptide chemistry. 相似文献
39.
The involvement of children in research studies is historically fraught with difficulties. Experiments on children without their consent or knowledge have been carried out in the past and thus the need for stringent ethical control is undoubtedly necessary. However this paper argues that the need to protect children from unethical research has somehow become entwined in the web of secrecy that surrounds the very nature of child abuse. In the name of 'protection' are children in danger of not having their voice heard?
In the foreword to 'Listening to Children' (Alderson, 1995) Roger Singleton writes, 'much research is carried out on and about children, but seldom with children. Children themselves are often strangely silent'. This paper draws on recent literature on the institutional abuse of young people in residential care and the lack of voice that those abused in residential care have traditionally had, suggesting that their silence is not 'strange' but perhaps contrived.
This paper does not repeat the work of Alderson (1995) and make suggestions as to how research with children may best be carried out, but seeks to address the issues in relation to research with children who are in institutions. 相似文献
In the foreword to 'Listening to Children' (Alderson, 1995) Roger Singleton writes, 'much research is carried out on and about children, but seldom with children. Children themselves are often strangely silent'. This paper draws on recent literature on the institutional abuse of young people in residential care and the lack of voice that those abused in residential care have traditionally had, suggesting that their silence is not 'strange' but perhaps contrived.
This paper does not repeat the work of Alderson (1995) and make suggestions as to how research with children may best be carried out, but seeks to address the issues in relation to research with children who are in institutions. 相似文献
40.
O. A. MIRGHANI† E. O. EL AMIN† M. E. S. ALI† H. S. OSMAN‡ B. HAMAD§ 《Medical education》1988,22(4):314-316
The community-based course presented is a longitudinal course running through four semesters in the Faculty of Medicine, University of Gezira, Sudan. Students combine their regular work in primary health care centres with attachments to a number of families in Wad Medani town. They continue to visit these families regularly throughout their entire medical course with the aim of studying them and helping them with some of their medical and psychosocial problems. 相似文献