首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   534篇
  免费   24篇
儿科学   45篇
妇产科学   13篇
基础医学   80篇
口腔科学   11篇
临床医学   34篇
内科学   111篇
皮肤病学   2篇
神经病学   79篇
特种医学   26篇
外科学   68篇
综合类   3篇
一般理论   2篇
预防医学   48篇
眼科学   9篇
药学   7篇
中国医学   2篇
肿瘤学   18篇
  2023年   2篇
  2022年   5篇
  2021年   7篇
  2020年   8篇
  2019年   7篇
  2018年   17篇
  2017年   13篇
  2016年   13篇
  2015年   13篇
  2014年   13篇
  2013年   40篇
  2012年   37篇
  2011年   30篇
  2010年   17篇
  2009年   18篇
  2008年   28篇
  2007年   27篇
  2006年   25篇
  2005年   32篇
  2004年   30篇
  2003年   28篇
  2002年   19篇
  2001年   8篇
  2000年   10篇
  1999年   9篇
  1998年   12篇
  1997年   5篇
  1996年   3篇
  1995年   5篇
  1994年   4篇
  1993年   3篇
  1992年   7篇
  1991年   5篇
  1990年   7篇
  1989年   6篇
  1988年   4篇
  1987年   6篇
  1986年   2篇
  1985年   2篇
  1984年   6篇
  1983年   2篇
  1982年   8篇
  1981年   3篇
  1976年   1篇
  1975年   2篇
  1973年   2篇
  1971年   1篇
  1970年   1篇
  1968年   2篇
  1967年   2篇
排序方式: 共有558条查询结果,搜索用时 31 毫秒
1.
2.
3.
Highly malignant cell lines and low-malignant cell lines isolated from three different methylcholanthrene-induced murine fibrosarcomas were examined for their ability to attach to plastic dishes and collagen-coated dishes under serumfree conditions and in the presence of serum. Most of the cells from the three highly malignant lines attached and spread under all conditions. By 72h, there was a significant increase in the number of cells indicating that at least some of the cells had undergone division (even in the absence of serum). In contrast, fewer of the cells from the three low-malignant lines attached and spread on the plastic or collagen substrates in the absence of serum or in the presence of 0.1 per cent serum. However, when 15g laminin per dish was added along with the lowmalignant cells, they then attached and spread on the plastic and collagen-coated dishes. Previous studies have indicated that the highly malignant lines express cell surface antigens that cross-react with laminin while the low-malignant cell lines do not. We speculate that the differences between the high- and low-malignant cells in the expression of cell surface laminin-like antigens contribute to the dissimilarities in attachment and spreading capacity. These differences may also contribute to the dissimilarity between these cells in malignant potential.  相似文献   
4.
To test the hypothesis that the same genetic loci confer susceptibility to, or protection from, disease in different populations, and that a combined analysis would improve the map resolution of a common susceptibility locus, we analyzed data from three studies that had reported linkage to bipolar disorder in a small region on chromosome 4p. Data sets comprised phenotypic information and genetic marker data on Scottish, Danish, and USA extended pedigrees. Across the three data sets, 913 individuals appeared in the pedigrees, 462 were classified, either as unaffected (323) or affected (139) with unipolar or bipolar disorder. A consensus linkage map was created from 14 microsatellite markers in a 33 cM region. Phenotypic and genetic data were analyzed using a variance component (VC) and allele sharing method. All previously reported elevated test statistics in the region were confirmed with one or both analysis methods, indicating the presence of one or more susceptibility genes to bipolar disorder in the three populations in the studied chromosome segment. When the results from both the VC and allele sharing method were considered, there was strong evidence for a susceptibility locus in the data from Scotland, some evidence in the data from Denmark and relatively less evidence in the data from the USA. The test statistics from the Scottish data set dominated the test statistics from the other studies, and no improved map resolution for a putative genetic locus underlying susceptibility in all three studies was obtained. Studies reporting linkage to the same region require careful scrutiny and preferably joint or meta analysis on the same basis in order to ensure that the results are truly comparable.  相似文献   
5.

Background  

To determine whether the use of an electronic, sensor based stethoscope affects the cardiac auscultation skills of undergraduate medical students.  相似文献   
6.
This longitudinal study examines continuity and discontinuity of attachment quality from infancy to late adolescence in a sample of 125 participants considered at birth to be at high-risk due to poverty. Strange Situations were conducted at 12 and 18 months; Adult Attachment Interviews were administered at age 19. Child and maternal characteristics and experiences and observational assessments of the families were explored as correlates of continuity and discontinuity in attachment. Contrary to findings of continuity from low-risk samples, analyses demonstrated no significant overall continuity in attachment security. Disorganized infants were significantly more likely than organized infants to be insecure or unresolved in late adolescence. Additionally, infant disorganization predicted unresolved abuse scores on the AAI for those participants who experienced childhood abuse. Significant correlates of continuity and change spanned a variety of age periods and included infant temperament, maternal life stress, family functioning at pre-adolescence, child maltreatment and features of the home environment. Findings are discussed as supporting the coherence of attachment over time.  相似文献   
7.
Genomic typing of in vitro amplified DNA with sequence-specific oligonucleotide (SSO) probes was performed for DRB1, DQA1, DQB1, DPA1 and DPB1 alleles in 54 random Norwegian rheumatoid arthritis (RA) patients and 181 healthy controls. DRB1 alleles encoding the serological specificity DR4 were found in 80% of the patients, compared to 34% of the controls (relative risk = 7.9, p less than 0.0001). All DR4-positive RA patients carried either DRB1*0401 (Dw4), 0404 (Dw14), or 0405 (Dw15), while no patients were found to carry DRB1*0402 (Dw10) or 0403 (Dw13). The frequency of the DRB1*0101 allele encoding DR1 was not increased, even among DR4-negative RA patients, and we were unable to detect any sharing of other class II alleles among DR4-negative patients. No contribution of any DQA1, DQB1, DPA1 or DPB1 alleles to RA susceptibility could be detected. The results suggest that in the Norwegian population RA is primarily associated with a shared sequence at residues 67-74 of the DR beta 1 chain, but only when this sequence is expressed on DR4 molecules.  相似文献   
8.
Bowlby's attachment theory is a theory of psychopathology as well as a theory of normal development. It contains clear and specific propositions regarding the role of early experience in developmental psychopathology, the importance of ongoing context, and the nature of the developmental process underlying pathology. In particular, Bowlby argued that adaptation is always the joint product of developmental history and current circumstances (never either alone). Early experience does not cause later pathology in a linear way; yet, it has special significance due to the complex, systemic, transactional nature of development. Prior history is part of current context, playing a role in selection, engagement, and interpretation of subsequent experience and in the use of available environmental supports. Finally, except in very extreme cases, early anxious attachment is not viewed as psychopathology itself or as a direct cause of psychopathology but as an initiator of pathways probabilistically associated with later pathology.  相似文献   
9.
10.
In clinical practice, it is commonly assumed that occlusal splints have therapeutic value in the treatment of temporomandibular disorders (TMD), but the evidence based on randomized controlled trials is scarce. This study evaluated the short-term (10-week) efficacy of a stabilization splint in subjects with recurrent secondary otalgia and active TMD treatment need using a randomized, controlled, double-blind design. Thirty-six subjects were randomly allocated to the two treatment groups: the stabilization splint and the control splint group. After 10 weeks' treatment, the intensity of secondary otalgia, measured on a VAS scale (from 0 to 100 mm), decreased statistically significantly in the stabilization splint group (t 2.12; P 0.006), but not in the control group. Improvement in active TMD treatment need in subjects showing moderate or severe signs and symptoms of TMD was reported significantly more often in the stabilization splint group than in the control splint group (χ2 5.71; P .017). A statistically significant decrease in the Helkimo clinical dysfunction index was seen in the subjects with stabilization splint (Z -2.63; P .009), but not in the subjects with control splint. The results indicate that the use of a stabilization splint is beneficial with regard to secondary otalgia and active TMD treatment need.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号