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   2531篇
  免费   252篇
  国内免费   8篇
耳鼻咽喉   128篇
儿科学   84篇
妇产科学   47篇
基础医学   385篇
口腔科学   19篇
临床医学   357篇
内科学   475篇
皮肤病学   12篇
神经病学   201篇
特种医学   47篇
外科学   320篇
综合类   22篇
一般理论   1篇
预防医学   252篇
眼科学   26篇
药学   132篇
中国医学   1篇
肿瘤学   282篇
  2023年   16篇
  2022年   35篇
  2021年   74篇
  2020年   37篇
  2019年   67篇
  2018年   66篇
  2017年   50篇
  2016年   70篇
  2015年   79篇
  2014年   93篇
  2013年   124篇
  2012年   180篇
  2011年   216篇
  2010年   109篇
  2009年   94篇
  2008年   177篇
  2007年   166篇
  2006年   152篇
  2005年   151篇
  2004年   148篇
  2003年   140篇
  2002年   119篇
  2001年   28篇
  2000年   39篇
  1999年   38篇
  1998年   27篇
  1997年   24篇
  1996年   13篇
  1995年   10篇
  1994年   20篇
  1993年   18篇
  1992年   25篇
  1991年   20篇
  1990年   14篇
  1989年   19篇
  1988年   14篇
  1987年   15篇
  1986年   16篇
  1985年   22篇
  1984年   12篇
  1983年   8篇
  1982年   7篇
  1979年   4篇
  1975年   5篇
  1972年   4篇
  1971年   2篇
  1968年   2篇
  1965年   2篇
  1957年   2篇
  1954年   2篇
排序方式: 共有2791条查询结果,搜索用时 15 毫秒
31.
Pathogenic germline variation in the microRNA processing gene DICER1 gives rise to an autosomal dominant, tumor‐predisposition disorder. Conditional deletion of Dicer1 in murine dental epithelium shows that it controls tooth patterning, size, number, and shape. The human dental phenotype of people with germline pathogenic variation in DICER1 is unknown. DICER1‐carriers (n = 57) and family controls (n = 55) were evaluated at the NIH Clinical Center dental clinic as part of a comprehensive medical evaluation. Digital panoramic radiographs, bite‐wing radiographs, and oral photographs were collected. A single observer, blind to DICER1 status, reviewed the dental records and determined the presence or absence of 11 dental characteristics as described in the clinic notes, radiographs, or oral photographs. Subjective phenotypes were reviewed on radiographs by two examiners (blind to DICER1 status) for the presence or absence of the dental characteristics to reduce inconsistencies. By simple association, bulbous crown, periodontitis, and taurodontism were all significant (p < .05). Logistic regression with chi‐square maximum likelihood estimates showed that bulbous crown and periodontitis remained significant. Recognition of these phenotypes may aid identification of individuals and families at risk for DICER1‐associated neoplasms. These findings may also guide dental care for individuals with germline DICER1 pathogenic variation.  相似文献   
32.
The Bioperl toolkit: Perl modules for the life sciences   总被引:36,自引:4,他引:36  
The Bioperl project is an international open-source collaboration of biologists, bioinformaticians, and computer scientists that has evolved over the past 7 yr into the most comprehensive library of Perl modules available for managing and manipulating life-science information. Bioperl provides an easy-to-use, stable, and consistent programming interface for bioinformatics application programmers. The Bioperl modules have been successfully and repeatedly used to reduce otherwise complex tasks to only a few lines of code. The Bioperl object model has been proven to be flexible enough to support enterprise-level applications such as EnsEMBL, while maintaining an easy learning curve for novice Perl programmers. Bioperl is capable of executing analyses and processing results from programs such as BLAST, ClustalW, or the EMBOSS suite. Interoperation with modules written in Python and Java is supported through the evolving BioCORBA bridge. Bioperl provides access to data stores such as GenBank and SwissProt via a flexible series of sequence input/output modules, and to the emerging common sequence data storage format of the Open Bioinformatics Database Access project. This study describes the overall architecture of the toolkit, the problem domains that it addresses, and gives specific examples of how the toolkit can be used to solve common life-sciences problems. We conclude with a discussion of how the open-source nature of the project has contributed to the development effort.  相似文献   
33.
Uterine smooth muscle tumors range from the very common benign leiomyoma to the uncommon, but frequently lethal, leiomyosarcoma. Morphological and clinical differences between these tumors are presumed to result from differences in gene expression. To test this hypothesis, RNAs from four normal uterine myometria, seven uterine leiomyomas, and nine uterine leiomyosarcomas were profiled using microarrays of oligonucleotides representing about 7,000 unique probe sets. RNAs whose levels distinguished any of the three sample types were selected by analysis of variance (ANOVA). The 153 (2.2% of the total) probe sets representing 146 unique genes with the highest test statistic selected for further analysis met minimum ratio and range thresholds between groups. Cluster analysis distinguished benign and malignant samples at the first node, and myometrium and leiomyoma were resolved in a secondary node. Downregulation of specific genes in uterine leiomyosarcoma was the most common pattern of differential gene expression selected by the three-way ANOVA. Four extrauterine leiomyosarcomas had profiles most similar to that of the uterine leiomyosarcomas. Functional analysis of the 146 genes did not reveal any strong biological theme. These genes were distributed throughout the genome, but there was slight overrepresentation of genes on 1p and 2q. These genes define a tumor signature for uterine smooth muscle neoplasia, and they suggest that the molecular pathways in leiomyoma and leiomyosarcoma are distinct.  相似文献   
34.
After bilateral labyrinthectomy the maximum slow phase velocity of flash-induced nystagmus (FIN) was diminished; the flash induced after-nystagmus was always absent. Unilateral labyrinthectomy resulted in a weaker FIN response on stimulation of both eyes, but the best response was seen after contralateral stimulation. These findings are discussed in relation to reported effects of labyrinthectomy on OKN, "central nystagmus" and vestibular nuclear discharge activity.  相似文献   
35.
As a philosophical position, pragmatism can be critiqued to distinguish truth only with methods that bring about desired results, predominantly with scientific enquiry. The article hopes to dismiss this oversimplification and propose that within mental health nursing, enquiry enlightened by pragmatism can be anchored to methods helping to tackle genuine human problems. Whilst pragmatists suggest one reality exists, fluctuating experiences and shifting beliefs about the world can inhabit within; hence, pragmatists propose reality has the potential to change. Moreover, pragmatism includes being cognisant of what works to whom reality concerns, making reality context-driven, with a view to understand how actions shape experiences so what is generated has usefulness. Hence, it somewhat follows pragmatism can inform mental health nursing, after all, nursing is a discipline of action, and awareness is needed in how actions produce experiences that patients find helpful. Given the principles of recovery are preferably adopted in mental health care, the paper will explore how pragmatism can help nurses move towards that goal; specifically, with patients voicing their experiences. This is because like pragmatism, recovery subscribes to hope that reality can progress, and through meaningful experiences and beliefs, patients have expertise about personal difficulties alongside how life may flourish, despite mental illness.  相似文献   
36.
37.
38.
39.
Archives of Sexual Behavior - Despite the gaining popularity in mainstream media of the phenomenon that is BDSM, empirical research on the motives and underlying psychological mechanisms driving...  相似文献   
40.
We looked for the presence of the anti-Hu antibody in the sera from 50 normal subjects; 44 patients with small cell lung cancer, not associated with paraneoplastic disease; and 25 patients with small cell lung cancer associated with paraneoplastic sensory neuropathy, encephalomyelitis, or both. Using the avidin-biotin immunoperoxidase method and a highly sensitive quantitative Western blot analysis, the anti-Hu antibody was not detected in the 50 normal human sera. Seven of the 44 patients with small cell lung cancer but no paraneoplastic syndrome had detectable levels (average titer, 76 U/ml) of anti-Hu antibody on Western blot. These levels are significantly lower than the average titer of the 25 patients who had small cell lung cancer and paraneoplastic sensory neuropathy or encephalomyelitis (average titer, 4,592 U/ml). In the group with nonparaneoplastic small cell lung cancer (low anti-Hu titer) there was a predominance of women (5 women: 2 men), and all patients had "limited" disease when diagnosed. In the antibody-negative group the sex ratio was 16 women to 21 men and 51% of the patients had "extensive" disease. None of the 7 patients with a low-titer anti-Hu antibody developed a paraneoplastic syndrome by the time of writing. The anti-Hu antibody appears, when present, to be a good marker for small cell lung cancer and, when present at high titer, for small cell lung cancer associated with a paraneoplastic syndrome.  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