全文获取类型
收费全文 | 1546998篇 |
免费 | 122224篇 |
国内免费 | 6807篇 |
专业分类
耳鼻咽喉 | 19404篇 |
儿科学 | 49339篇 |
妇产科学 | 40897篇 |
基础医学 | 213675篇 |
口腔科学 | 41115篇 |
临床医学 | 137583篇 |
内科学 | 323673篇 |
皮肤病学 | 37406篇 |
神经病学 | 129014篇 |
特种医学 | 61593篇 |
外国民族医学 | 368篇 |
外科学 | 236115篇 |
综合类 | 32580篇 |
现状与发展 | 2篇 |
一般理论 | 469篇 |
预防医学 | 125806篇 |
眼科学 | 32260篇 |
药学 | 108627篇 |
7篇 | |
中国医学 | 2898篇 |
肿瘤学 | 83198篇 |
出版年
2019年 | 12589篇 |
2018年 | 20042篇 |
2017年 | 15001篇 |
2016年 | 17120篇 |
2015年 | 19177篇 |
2014年 | 25056篇 |
2013年 | 37966篇 |
2012年 | 50813篇 |
2011年 | 53436篇 |
2010年 | 31620篇 |
2009年 | 29310篇 |
2008年 | 48904篇 |
2007年 | 52199篇 |
2006年 | 52233篇 |
2005年 | 50661篇 |
2004年 | 48109篇 |
2003年 | 46252篇 |
2002年 | 43662篇 |
2001年 | 70861篇 |
2000年 | 72780篇 |
1999年 | 60984篇 |
1998年 | 17536篇 |
1997年 | 15707篇 |
1996年 | 16650篇 |
1995年 | 16798篇 |
1994年 | 15597篇 |
1993年 | 14581篇 |
1992年 | 49655篇 |
1991年 | 48092篇 |
1990年 | 46192篇 |
1989年 | 43877篇 |
1988年 | 40730篇 |
1987年 | 39914篇 |
1986年 | 37611篇 |
1985年 | 36211篇 |
1984年 | 27537篇 |
1983年 | 23118篇 |
1982年 | 14427篇 |
1981年 | 12926篇 |
1980年 | 12201篇 |
1979年 | 24583篇 |
1978年 | 17810篇 |
1977年 | 15073篇 |
1976年 | 13752篇 |
1975年 | 14426篇 |
1974年 | 16973篇 |
1973年 | 16282篇 |
1972年 | 15007篇 |
1971年 | 13860篇 |
1970年 | 12654篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
W. Ziegler D. von Cramon 《European archives of psychiatry and clinical neuroscience》1986,236(1):44-49
Summary This paper deals with a particular aspect of speech motor control in patients suffering from apraxia of speech. Three experiments are reported concerning the phase relations between individual speech gestures. These include the timing of laryngeal, velar and labial movements relative to lingual gestures.A total of 8 patients and 12 normal controls were examined using speech material which was designed according to appropriate phonetic paradigms. Evaluation was performed on the basis of speech signal parameters referring to the kinematics of inter-articulatory phasing. Deviations of the patient group were found in all three experiments. This suggests that disturbed phase relations of individual speech movements are a general feature of apraxic speech. It is further hypothesized that the described motor symptoms are the origin of a variety of phonemic errors. Support for this view is provided by appropriate examples which refer to the examined paradigms. By this argument, much of the disturbed phonemic structure of apraxic speech may be accounted for by timing deficits. 相似文献
992.
993.
In brain regions containing noradrenergic (NA) cell bodies or terminals, DSP-4 induces changes in the activity of catecholamine-synthesizing enzymes which suggest that central NA neurons are lesioned by this neurotoxin. In contrast, the lack of change in the same enzymatic activities in an area containing mostly adrenergic (A) neurons (C2 region), favors the hypothesis of a resistance of the A neurons to DSP-4. Furthermore, the enzymatic changes observed in peripheral organs suggest a peripheral activation of the NA cell bodies in response to lesioning of the sympathetic terminals by DSP-4. 相似文献
994.
995.
M Gómez-Silva L Garza-Oca?as N Waksman V Rivas A Pi?eyro-López 《Toxicology in vitro》2005,19(1):47-53
T-514 (Peroxisomicine A(1)) from Karwinskia humboldtiana is a dimeric hydroxyanthracenone with a highly selective cytotoxic effect on tumor cells. We evaluated the metabolism of this compound in two in vitro systems (liver microsomes and hepatocytes) and assessed the cytotoxicity of its metabolites on normal and tumor cells. Microsomes (12.5, 125 and 250 microg of protein/ml) and hepatocytes (1 x 10(6) cells/ml) were incubated with the toxin (25 microM) for 0.5, 1, 3, 6, 9, 12 and 24 h and the samples were examined using chromatographic analysis and UV spectra. Two metabolites (M1 and M2) were detected in the rat microsomes and one (M1) in the monkey microsomes. The retention times and UV spectra of the peaks were very similar to those of the toxin T-514. M1 was isolated and identified as a mixture of two isomers. The cytotoxicity of the metabolites was evaluated in Chang liver and Hep G2 cells but they did not show the selective cytotoxic effect on tumor cells seen in the original compound. 相似文献
996.
Pamela D Reiter Adam A Rosenberg Robert Valuck Kathryn Novak 《Journal of perinatology》2005,25(2):125-129
OBJECTIVE: To determine the effectiveness of a 10-day subcutaneous erythropoietin (rHuEpo) course of 300 units per kg per dose plus oral iron compared to oral iron alone in anemic infants during their convalescent phase of illness. STUDY DESIGN: Prospective, randomized trial performed at a 40-bed, teaching, referral, level III, neonatal intensive care unit. Infants with a gestational age at birth of less than 32 weeks, hematocrit of less than or equal to 28% with a corrected reticulocyte count of less than or equal to 5%, postconceptual age of less than 48 weeks or 5 months chronological age, and a diagnosis of anemia of prematurity were considered for inclusion. Major outcome parameters included hematocrit, corrected reticulocyte count and red cell transfusion requirements. RESULTS: A total of 60 infants were enrolled (n=30 per group). Infants randomized to rHuEpo had a significantly higher post-treatment hematocrit and corrected reticulocyte count than infants in the iron only group (p<0.001). There was a trend towards fewer red cell requirements in the rHuEpo group. CONCLUSIONS: The rHuEpo regimen studied here was associated with an acute improvement in hematocrit and corrected reticulocyte counts. This study did not demonstrate a statistically significant decrease in transfusion therapy, in part related to increased subsequent use of rHuEpo in the control group. Taken together, these data demonstrate that this regimen can effectively treat anemia in convalescent premature infants. 相似文献
997.
998.
999.
1000.