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   12977篇
  免费   964篇
  国内免费   24篇
耳鼻咽喉   83篇
儿科学   505篇
妇产科学   430篇
基础医学   1461篇
口腔科学   216篇
临床医学   2406篇
内科学   1874篇
皮肤病学   217篇
神经病学   1367篇
特种医学   301篇
外科学   1203篇
综合类   226篇
一般理论   28篇
预防医学   1787篇
眼科学   174篇
药学   863篇
  1篇
中国医学   48篇
肿瘤学   775篇
  2023年   68篇
  2022年   110篇
  2021年   221篇
  2020年   158篇
  2019年   221篇
  2018年   279篇
  2017年   248篇
  2016年   243篇
  2015年   266篇
  2014年   368篇
  2013年   551篇
  2012年   868篇
  2011年   917篇
  2010年   511篇
  2009年   462篇
  2008年   815篇
  2007年   878篇
  2006年   799篇
  2005年   788篇
  2004年   840篇
  2003年   733篇
  2002年   707篇
  2001年   171篇
  2000年   176篇
  1999年   161篇
  1998年   150篇
  1997年   138篇
  1996年   114篇
  1995年   107篇
  1994年   104篇
  1993年   73篇
  1992年   101篇
  1991年   109篇
  1990年   88篇
  1989年   85篇
  1988年   82篇
  1987年   81篇
  1986年   70篇
  1985年   70篇
  1984年   65篇
  1983年   77篇
  1982年   71篇
  1981年   69篇
  1980年   61篇
  1979年   57篇
  1978年   63篇
  1977年   45篇
  1976年   47篇
  1975年   44篇
  1974年   52篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
The flavonoids isolated from the leaves ofRhododendron brachycarpum, were identified as quercetin, avicularin, quercitrin and hyperin.  相似文献   
72.
73.
A successful feature of the 4th-year curriculum in the Medical Faculty of the Queen's University, Belfast has been the development of interdisciplinary teaching in a three-week joint course to which several clinical departments contribute...Co-ordinated teaching of topics of common interest in small groups included, until the academic year 1987/88, a three-hour session on medical ethics. In the spring of 1987 the authors approached the Department of Philosophy at Queen's; subsequently proposals for a formal multidiscipinary course in medical ethics for 4th-year clinical students in the Medical Faculty, for the academic year 1987/88, were approved by the Education Committee of the Medical Faculty.  相似文献   
74.
We evaluated the relationship between life events, social support, coping, and depression in 27 male inpatients meeting the requirements for Research Diagnostic Criteria major depressive disorder and in 35 age- and sex-matched nonpatients. Overall, the hospitalized depressed patients reported significantly more events and difficulties than did the controls, but this difference in statistical significance disappeared after excluding from analysis "non-independent" happenings which could have been brought on by depression. More hospitalized depressed patients (23 of 27, or 85%) than controls (8 of 35, or 22.9%) experienced markedly threatening events and difficulties ("marked adversities") in the 6 months before their interview. The depressed group also reported having significantly fewer social supports, being less satisfied with the emotional component of this support, and using more emotion-focused coping than the controls. A discriminant analysis predicted depressive status from a combination of marked adversities, reduced number of social supports, and greater use of emotion-focused coping. The results indicate that the relationship of life events to depression is complex. The excess number of events might be partly a product of dysfunctional behavior that "produces" depression-related events which might, in turn, exacerbate depression; simultaneously, patients are more likely to experience highly adverse events which might precipitate the depression in the first place. Reduced social supports and the use of emotion-focused coping appear to also be associated with hospitalization for major depression.  相似文献   
75.
Immunostimulatory oligodeoxynucleotides (IS ODN) can mediate a number of immunologic effects. We previously demonstrated that treatment of B cell chronic lymphocytic leukemia (B-CLL) cells with one class of IS ODN, CpG ODN, alters their phenotype and increases their immunogenicity. Here, we demonstrate that in contrast to the classic understanding of CpG ODN as inhibitors of B cell apoptosis, IS ODN including CpG ODN induce apoptosis in B-CLL cells. It is important that these changes are seen not only with CpG ODN but with ODN that lack the classical CpG motif. B-CLL cells from 20 subjects were treated in vitro with IS ODN for up to 7 days. IS ODN treatment resulted in increased numbers of apoptotic cells in 13 out of 20 B-CLL samples. IS ODN enhanced apoptosis in samples with 13q deletion as a single aberration and had a heterogeneous effect on apoptosis in samples with other aberrations including 17p deletion, 11q deletion, or trisomy 12. Induction of apoptosis did not correlate with expression of the CpG ODN receptor Toll-like receptor 9. Apoptosis was dependent on the activation of caspases and was accompanied by up-regulation of CD95/Fas and its ligand. We conclude that IS ODN including CpG ODN can induce apoptosis of most B-CLL samples. The ability of IS ODN to induce apoptosis differs based on cytogenetic status. Up-regulation of CD95/Fas may play a role in IS ODN-induced apoptosis of B-CLL.  相似文献   
76.
Costello syndrome (CS) is a RASopathy caused by activating germline mutations in HRAS. Due to ubiquitous HRAS gene expression, CS affects multiple organ systems and individuals are predisposed to cancer. Individuals with CS may have distinctive craniofacial features, cardiac anomalies, growth and developmental delays, as well as dermatological, orthopedic, ocular, and neurological issues; however, considerable overlap with other RASopathies exists. Medical evaluation requires an understanding of the multifaceted phenotype. Subspecialists may have limited experience in caring for these individuals because of the rarity of CS. Furthermore, the phenotypic presentation may vary with the underlying genotype. These guidelines were developed by an interdisciplinary team of experts in order to encourage timely health care practices and provide medical management guidelines for the primary and specialty care provider, as well as for the families and affected individuals across their lifespan. These guidelines are based on expert opinion and do not represent evidence‐based guidelines due to the lack of data for this rare condition.  相似文献   
77.
This study was undertaken in order to compare the interphase and metaphase cytogenetics of 28 patients with ETV6/RUNX1 positive acute lymphoblastic leukemia, at diagnosis and relapse. The median time to relapse was 26 months. The significant fusion positive population heterogeneity revealed at interphase by a commercial probe for ETV6/RUNX1 fusion has not been described before. Six diagnostic samples had a single abnormal population; others had up to five each, which differed in the numbers of RUNX1 signals, and in the retention or loss of the second ETV6 signal. In contrast, the number of fusion signals was more constant. At relapse, there were fewer populations; the largest or unique clone was sometimes a re-emergence of a minor, diagnostic one, with a retained copy of ETV6 and the most RUNX1 signals. Abnormal, fusion negative clones were identified in bone marrow samples at extra-medullary relapse. Variant three or four-way translocations, which involved chromosomes 12 and 21, were prominent among the complex rearrangements revealed by metaphase FISH. The frequency of their occurrence at diagnosis and reappearance at relapse, sometimes accompanied by minor clonal evolution, was another new observation. Other recurrent cytogenetic features included a second copy of the fusion signal in six cases, partial duplication of the long arm of the X chromosome in two cases, and trisomy 10 in three cases. In comparing our data with previously reported cases, a picture is beginning to emerge of certain diagnostic features, which may provide circumstantial evidence of an increased risk of relapse.  相似文献   
78.

Background  

Decision aids (DA) to assist patients in evaluating treatment options and sharing in decision making have proliferated in recent years. Most require high literacy and do not use plain language principles. We describe one of the first attempts to design a decision aid using principles from reading research and document design. The plain language DA prototype addressed treatment decisions for localized prostate cancer. Evaluation assessed impact on knowledge, decisions, and discussions with doctors in men newly diagnosed with prostate cancer.  相似文献   
79.
OBJECTIVE: To determine the optimal strategy to investigate mumps virus infection in a partially vaccinated cohort. STUDY DESIGN: 122 oral fluid and serum samples were collected in a recent outbreak in Ireland. The largest age cohort, students aged 18-21 years old attending third level institutions, were investigated using virus isolation, detection of mumps specific IgM, IgG, RT-PCR and molecular genotyping. RESULTS: 97% of patients had both detectable serum IgM and IgG. Mumps virus RNA was detected in 17 oral fluid samples and 14 of these originated from a single geographic location. Only 6 of the IgM positive samples had detectable mumps virus RNA whereas this could be detected in 11 IgM negative samples. Genotyping studies revealed that genotypes G and J were co-circulating during this outbreak. CONCLUSIONS: The use of an oral fluid sample to detect mumps virus RNA and IgM offers a major improvement over serological diagnosis in acute infection in both non-vaccinated or partially vaccinated individuals, and has the advantage that specimens are collected non-invasively.  相似文献   
80.
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