全文获取类型
收费全文 | 4173篇 |
免费 | 345篇 |
国内免费 | 53篇 |
专业分类
耳鼻咽喉 | 258篇 |
儿科学 | 114篇 |
妇产科学 | 21篇 |
基础医学 | 519篇 |
口腔科学 | 1515篇 |
临床医学 | 220篇 |
内科学 | 79篇 |
皮肤病学 | 105篇 |
神经病学 | 110篇 |
特种医学 | 66篇 |
外科学 | 864篇 |
综合类 | 429篇 |
预防医学 | 105篇 |
眼科学 | 29篇 |
药学 | 86篇 |
1篇 | |
中国医学 | 18篇 |
肿瘤学 | 32篇 |
出版年
2024年 | 4篇 |
2023年 | 58篇 |
2022年 | 87篇 |
2021年 | 123篇 |
2020年 | 142篇 |
2019年 | 153篇 |
2018年 | 181篇 |
2017年 | 101篇 |
2016年 | 154篇 |
2015年 | 136篇 |
2014年 | 327篇 |
2013年 | 299篇 |
2012年 | 212篇 |
2011年 | 272篇 |
2010年 | 218篇 |
2009年 | 201篇 |
2008年 | 204篇 |
2007年 | 184篇 |
2006年 | 181篇 |
2005年 | 139篇 |
2004年 | 136篇 |
2003年 | 131篇 |
2002年 | 120篇 |
2001年 | 99篇 |
2000年 | 76篇 |
1999年 | 82篇 |
1998年 | 56篇 |
1997年 | 72篇 |
1996年 | 51篇 |
1995年 | 40篇 |
1994年 | 35篇 |
1993年 | 32篇 |
1992年 | 42篇 |
1991年 | 21篇 |
1990年 | 16篇 |
1989年 | 20篇 |
1988年 | 20篇 |
1987年 | 14篇 |
1986年 | 10篇 |
1985年 | 14篇 |
1984年 | 22篇 |
1983年 | 15篇 |
1982年 | 18篇 |
1981年 | 12篇 |
1980年 | 17篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 5篇 |
1970年 | 1篇 |
排序方式: 共有4571条查询结果,搜索用时 31 毫秒
51.
Test of genetic heterogeneity of cleft lip with or without cleft palate as related to race and severity 总被引:6,自引:0,他引:6
The question of possible heterogeneity among population groups and phenotypic groups on the role of major gene in the etiology of cleft lip with or without cleft palate [CL(P)] was examined using the uniformly collected data in Hawaii. Complex segregation analysis was used to analyze patterns of family resemblance under the mixed model incorporating the effects of major gene and multifactorial inheritance. Analysis of the entire data showed superior fit of the mixed model including the effects of both major gene and multifactorial inheritance over the model of major gene alone or multifactorial inheritance alone. No significant heterogeneity could be detected between the high-incidence group (Oriental or Japanese) and the low-incidence group (non-Oriental) in the underlying general model, although higher heritability was observed in general. When families were classified into "severe" and "mild" phenotypes based on cleft lip vs. cleft lip and palate or unilateral vs. bilateral cleft in the proband, no significant differences could be detected between the two types in the underlying genetic model. 相似文献
52.
Pigments of the Gastrointestinal Tract: A Comparison of Light Microscopic and Electron Microscopic Findings 总被引:6,自引:0,他引:6
It is now apparent that light microscopy and histochemistry failed to identify correctly the nature and composition of pigments in various gastrointestinal tract melanoses. In most instances it was thought that the pigment was melanin or a melanin-like substance. Electron microscopy (EM) and electron-probe energy dispersive x-ray analysis have rectified these errors and have shown the following: in melanosis coli the pigment granules contain lipofuscin; in melanoses ilei the pigment granules may contain either silicates and titanium or hemosiderin; and in melanosis duodeni the pigment granules contain iron sulfide. In melanosis esophagi it is not clear what the pigment is; it could be melanin or lipofuscin. 相似文献
53.
内耳门周结构对内镜下脑桥小脑三角区手术的影响 总被引:3,自引:3,他引:3
目的:研究内耳门周结构对颞骨径路内镜下处理脑桥小脑三角区病变手术的影响,为临床开展相应手术提供参考。方法:在20例40侧成人尸头上模拟颞骨径路内窥镜手术,观察小脑下前动脉及内耳门后唇的变异,了解其对内窥镜导入及其手术的影响。结果:内耳门后唇隆起超过面神经脑桥小脑角段1/3以上者占27.5%(11侧)。小脑下前动脉在Ⅶ、Ⅷ脑神经外侧成袢者占22.5%(9侧)。内耳门后唇隆起合并小脑下前动脉袢在Ⅶ、Ⅷ脑神经之外侧者占7.5%(3侧)。结论:当内耳门后唇隆起超过面神经脑桥小脑角段1/3或小脑下前动脉弓在Ⅶ、Ⅷ脑神经之前时将对内窥镜导入有阻碍,当两种情况合并存在时要将内窥镜导入脑桥小脑三角区相当困难,不宜采用此种手术方式。 相似文献
54.
Roger L. Ladda Jonathan Zonana Jeanette C. Ramer Maria J. Mascari Peter K. Rogan 《American journal of medical genetics. Part A》1993,47(4):550-555
Brother were affected with severe congenital contractures, multiple cutaneous manifestations of ectodermal dysplasia, cleft lip/palate, and psychomotor and growth impairment. High resolution prometaphase chromosomes were normal. Molecular studies of DNA markers, closely flanking the X-linked hypohidrotic ectodermal dysplasia locus, did not show evidence of a submicroscopic deletion from the Xq12-q13 region. The parents and a normal sister exhibited none of these findings. This constellation of anomalies appears to represent a unique AR or XLR syndrome. © 1993 Wiley-Liss, Inc. 相似文献
55.
A family with cardiac malformation, cleft lip-palate, short stature, microcephaly, distally placed thumbs, short 2nd and 5th fingers, long and broad 1st toes, broad distance between 1st and 2nd toes and mediodorsal curvature of the 4th toes with syndactyly of the 2nd and 3rd toes has been described as having a new syndrome. While some members of the family had full signs of the syndrome, others had similar but fewer and less severe anomalies of the same structures. The presence of common findings in three generations, its variable expressivity and pleiotropism, and the non-consanguineous history in the parents suggest that the inheritance is autosomal dominant. 相似文献
56.
Robert E. Nickel De-Ann M. Pillers Mark Merkens R. Ellen Magenis Deborah A. Driscoll Beverly S. Emanuel Jonathan Zonana 《American journal of medical genetics. Part A》1994,52(4):445-449
Approximately 5% of children with neural tube defects (NTDs) have a congenital heart defect and/or cleft lip and palate. The cause of isolated meningomyelocele, congenital heart defects, or cleft lip and palate has been largely thought to be multifactorial. However, chromosomal, teratogenic, and single gene causes of combinations of NTDs with congenital heart defects and/or cleft lip and palate have been reported. We report on 3 patients with meningomyelocele, congenital heart defects, and 22q11 deletions. Two of the children had the clinical diagnosis of velo-cardio-facial syndrome (VCFS); both also have bifid uvula. The third child had DiGeorge sequence (DGS). The association of NTDs with 22q11 deletions has not been reported previously. An accurate diagnosis of the 22q11 deletions is critical as this micro-deletion and its associated clinical problems is transmitted as an autosomal dominant trait due to the inheritance of the deletion-bearing chromosome. We recommend that all children with NTDs and congenital heart defects, with or without cleft palate, have cytogenetic and molecular studies performed to detect 22q11 deletions. © 1994 Wiley-Liss, Inc. 相似文献
57.
Mitchell LE, Risch N. Correlates of genetic risk for non-syndromic cleft lip with or without cleft palate. Clin Genet 1993: 43: 255–260. © Munksgaard, 1993 Multivariate analysis was used to determine which characteristics: sex of the proband, sibling sex, severity of the proband's defect or family history, are the best predictors of recurrence risk among siblings of individuals with non-syndromic cleft lip with or without cleft palate (CL \pm P). Sibling recurrence risks are not significantly related to the sex of the proband. Severity of the proband's defect, classified by the extent of the lip defect (unilateral versus bilateral), was found to be a significant predictor of sibling recurrence, whereas involvement of the palate in the proband's defect was not. A positive family history of clefting (i.e. at least one affected first-degree relative in addition to the proband) and the sex of the sibling were also found to be significant predictors of sibling recurrence. The associations between sibling risk and family history, and sibling risk and bilaterality of the proband's defect appear to be mildly confounded. After adjusting for the effects of family history, the risk to siblings of probands with bilateral lip defects is twice the risk to siblings of probands with unilateral defects (O.R. = 2.00; 95% C.I. 1.25-3.19). A positive family history of clefting increases the risk to siblings by greater than 4-fold (O.R. =4.49; 95% C.I. 2.74-7.35), after adjusting for the extent of the proband's lip defect. These results provide a rational strategy for identifying subsets of the ‘at risk’ population which have markedly different recurrence risks. This information is important for genetic counseling, since it allows for more precise estimation of sibling recurrence risks in individual cases. Furthermore, our findings indicate that the power to detect linkage between a genetic marker or a candidate gene and CL \pm P will increase if the study population is ascertained through individuals with bilcteral clefts of the lip, rather than through individuals with either unilateral or bilateral CL \pm P. 相似文献
58.
将人机交互领域中研究的唇读技术应用于康复工程之中,设计了一个基于视觉语言的语音合成系统。该系统特别针对后天致残,丧失语音能力的人设计,采用了一种特定条件下的汉语可视语音数据库。不同于现有的数据库,该数据库的设计具有以下特点:采用了非对称唇形轮廓模型,提取了嘴唇突出度的信息;针对汉语音节的特点,增强了汉字音节中信息变化过程;兼顾未来唇读技术的发展,以音节为基本元素,具有可扩充性。采用运动检测和数学形态学的办法提取唇动图像序列中的唇形区域,并从中提取非对称唇形轮廓模型特征参数,同时通过计算部分参数对时间的差分,来获得唇形轮廓的动态信息。基于隐马尔可夫模型的学习和识别实验表明,该数据库的设计方法合理,所选的唇动特征用能够将识别效果平均提高25%。 相似文献
59.
A new inbred mouse strain, SW/Fr, developed from a random-bred SW stock has a 6% incidence of spontaneous cleft palate without cleft lip. SW/Fr mice close their palates comparatively late in development. After cortisone treatment, the mean of the distribution (mean time to reach palate stage 5) is shifted towards later gestational ages. There is no change in the variance of the distribution. These data lend further support to the hypothesis that cleft palate in mice may fit a model where a continuous distribution is separated into discontinuous parts by a developmental threshold, and that time of palate closure is an important component of liability to cleft palate. 相似文献
60.
Dvorak Abeliovich Esther Maor Nava Bashan Rivka Carmi 《American journal of medical genetics. Part A》1989,32(3):346-349
We report on three patients with duplication of distal 22q. One patient is a de novo carrier of the translocation t(21;22) (p13;q11), the other two are offspring of a translocation carrier t(10;22) (q26;q12). The clinical manifestations of these patients demonstrate the variability of the dup(22q) syndrome. 相似文献