全文获取类型
收费全文 | 1393篇 |
免费 | 138篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 63篇 |
妇产科学 | 21篇 |
基础医学 | 158篇 |
口腔科学 | 19篇 |
临床医学 | 181篇 |
内科学 | 219篇 |
皮肤病学 | 13篇 |
神经病学 | 121篇 |
特种医学 | 241篇 |
外科学 | 154篇 |
综合类 | 25篇 |
一般理论 | 1篇 |
预防医学 | 139篇 |
眼科学 | 29篇 |
药学 | 90篇 |
肿瘤学 | 65篇 |
出版年
2022年 | 9篇 |
2021年 | 22篇 |
2020年 | 13篇 |
2019年 | 21篇 |
2018年 | 32篇 |
2017年 | 20篇 |
2016年 | 16篇 |
2015年 | 20篇 |
2014年 | 30篇 |
2013年 | 46篇 |
2012年 | 56篇 |
2011年 | 45篇 |
2010年 | 34篇 |
2009年 | 34篇 |
2008年 | 48篇 |
2007年 | 51篇 |
2006年 | 46篇 |
2005年 | 45篇 |
2004年 | 37篇 |
2003年 | 43篇 |
2002年 | 28篇 |
2001年 | 29篇 |
2000年 | 33篇 |
1999年 | 15篇 |
1998年 | 34篇 |
1997年 | 32篇 |
1996年 | 43篇 |
1995年 | 26篇 |
1994年 | 26篇 |
1993年 | 34篇 |
1992年 | 33篇 |
1991年 | 29篇 |
1990年 | 38篇 |
1989年 | 45篇 |
1988年 | 47篇 |
1987年 | 51篇 |
1986年 | 41篇 |
1985年 | 39篇 |
1984年 | 23篇 |
1983年 | 18篇 |
1982年 | 29篇 |
1981年 | 24篇 |
1980年 | 21篇 |
1979年 | 19篇 |
1978年 | 17篇 |
1977年 | 14篇 |
1976年 | 27篇 |
1975年 | 17篇 |
1974年 | 10篇 |
1973年 | 10篇 |
排序方式: 共有1553条查询结果,搜索用时 15 毫秒
1.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence. 相似文献
2.
In the study of monozygotic twins relative to disease and risk factors, particular interest focuses on the subset who are discordant for some suspected risk factor (for example, smoking), since such twins constitute a natural case-control pair. In such studies, questionnaires designed to identify the status of all twin pairs are sometimes error prone and can yield misleading estimates of the concordance-discordance ratios. Greater efforts to verify the characteristics of apparently discordant pairs than to verify those of apparently concordant pairs can result in the 'unequal ascertainment' fallacy. Using the results of a questionnaire with known error rates and the 'apparent' frequencies yielded, we present unbiased, maximum likelihood estimates of the 'true' proportions of concordant and discordant pairs. concordant and discordant pairs. We also present approximate covariances among these estimates. 相似文献
3.
4.
静松灵[2-(2,4-二甲基苯胺基)-4,5-二氢噻唑,XT]是国内合成的麻醉物,经ip给药后,从大鼠尿中分离、纯化、鉴定了四个代谢产物。MB1即XT原形;MB3及MA2互为异构体,分别为2位、4位甲基氧化为羧基的产物;MA1则4位甲基氧化为羧基,二氢噻唑环中41位亚甲基氧化为羰基。初步实验表明:代谢产物MB3,MA2,MA1的药效与毒性均远低于原形药,大鼠与小鼠对XT的转化机制相近,但也存在种属的差异。 相似文献
5.
将真蓝(true blue)混悬液注入出生后7、14、28d大鼠眼球内,经过一定时间后,视神经内的轴突和少突胶质细胞被荧光标记。荧光强度在视神经眼球端强于视神经交叉端;出生后14~28d的幼鼠荧光标记明显强于出生后7d的幼鼠;不同年龄组的动物荧光标记普遍在注射荧光染料后的第5d显著增强。本研究表明,荧光染料可被视网膜的节细胞吸收,经轴突输送,然后,横向扩散到少突胶质细胞,扩散的通路可能是朗氏结旁区的轴胶连接。 相似文献
6.
7.
8.
M.M. Bialoskurski MA RN RM C.L. Cox MSc PhD RN & R.D. Wiggins PhD 《Journal of advanced nursing》2002,37(1):62-69
AIM: The aim of this study was to investigate the nature and organization of maternal needs and priorities in a neonatal unit. BACKGROUND: The relationship between maternal needs and priorities appears to be an under studied area in neonatal nursing. METHODS: A quantitative survey was carried out based on 209 mothers with premature infants. Two self-assessment schedules were used: critical care maternal needs inventory (J. Leske, Heart and Lung 15, 27-42) and a ranking scale. The data were analysed with multivariate analysis. FINDINGS: Data analysis revealed clear priorities in maternal needs. In particular the need for accurate infant related information was a priority for 93% of the mothers. Good communication practices with professionals were also valued. The mothers displayed altruistic behaviour, and self-related needs took second place. It is proposed that maternal needs demonstrate a hierarchical organization. CONCLUSION: It is important for nurses to consider the individual needs of the mothers, simply because the satisfaction of these needs is essential for maternal well-being. 相似文献
9.
To evaluate how steroid trials are currently used in the assessment of reversibility of air flow limitation, a postal questionnaire was sent to 355 consultant members of the British Thoracic Society working in England and Wales; 253 questionnaires were returned (71% response rate). Two respondents did not undertake steroid trials; of the remaining 251, 75% prescribed 30-40 mg oral prednisolone, with the commonest treatment period being 2 weeks. A high dose steroid inhaler was sometimes used as an alternative by 31% of respondents. Although 71% of respondents made lung function measurements on several occasions before starting steroids and 76% made measurements during treatment, 78% assessed patients on only one occasion at the end of the trials to ascertain its outcome. Weight, blood pressure and glycosuria were measured less frequently after the steroid treatment compared to the pre-trial period. Blood glucose and serum electrolytes were infrequently measured both before and after treatment. Wide variations exist in steroid trial regimens and current practice may neither provide definitive evidence of treatment benefit nor an adequate safeguard for patients against potential side-effects. 相似文献
10.
Noninvasive metabolic magnetic resonance (MR) imaging reflecting glucose metabolism in the aldose-reductase-sorbitol (ARS) pathway was performed in the rabbit head; after administration of the fluorinated glucose analogue 3-fluoro-3-deoxy-D-glucose (3FD-glucose), fluorine-19 images were generated. Images of 3FD-glucose showed significant 3FD-glucose uptake by adipose tissue, indicating its buffering effects in case of excess loads of glucose. Images of 3-fluoro-3-deoxy-D-sorbitol (3FD-sorbitol) demonstrated the spatial distribution of aldose reductase activities and significant sorbitol accumulation in the lens. Images of 3-fluoro-3-deoxy-D-fructose (3FD-fructose) showed preferential uptake of fructose by muscle tissue. The extremely low toxicity of 3FD-glucose indicates promise for its clinical application in metabolic imaging. 相似文献