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   31275篇
  免费   1287篇
  国内免费   125篇
耳鼻咽喉   479篇
儿科学   645篇
妇产科学   360篇
基础医学   4150篇
口腔科学   748篇
临床医学   2172篇
内科学   7710篇
皮肤病学   711篇
神经病学   2091篇
特种医学   1267篇
外国民族医学   1篇
外科学   5122篇
综合类   184篇
一般理论   3篇
预防医学   837篇
眼科学   489篇
药学   2156篇
  8篇
中国医学   88篇
肿瘤学   3466篇
  2023年   236篇
  2022年   424篇
  2021年   697篇
  2020年   442篇
  2019年   538篇
  2018年   634篇
  2017年   479篇
  2016年   566篇
  2015年   551篇
  2014年   793篇
  2013年   933篇
  2012年   1465篇
  2011年   1564篇
  2010年   849篇
  2009年   805篇
  2008年   1357篇
  2007年   1505篇
  2006年   1382篇
  2005年   1489篇
  2004年   1423篇
  2003年   1222篇
  2002年   1185篇
  2001年   1060篇
  2000年   980篇
  1999年   922篇
  1998年   347篇
  1997年   244篇
  1996年   261篇
  1995年   208篇
  1994年   181篇
  1993年   201篇
  1992年   648篇
  1991年   563篇
  1990年   546篇
  1989年   537篇
  1988年   524篇
  1987年   488篇
  1986年   463篇
  1985年   428篇
  1984年   317篇
  1983年   263篇
  1982年   166篇
  1979年   249篇
  1977年   189篇
  1973年   181篇
  1972年   188篇
  1971年   192篇
  1970年   176篇
  1969年   186篇
  1968年   170篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Deletions or translocations of chromosome band 13q14, the locus of the retinoblastoma gene (RB1), have been observed in a variety of hematological malignancies including myelodysplastic syndrome (MDS). We describe here a novel unbalanced translocation der(13)t(7;13)(p13;q14) involving 13q14 in a patient with MDS. A 66-year-old woman was diagnosed as having MDS, refractory anemia with excess of blasts (RAEB-1) because of 7.4% blasts and trilineage dysplasia in the bone marrow cells. G-banding and spectral karyotyping analyses showed complex karyotypes as follows: 46,XX,der(6)t(6;7)(q11;?),der(7)del(7)(?p13)t(6;7)(q?;q11)t(6;13)(q?;q?),der(13)t(7;13)(p13;q14). Fluorescence in situ hybridization (FISH) analyses demonstrated that one allele of the RB1 gene and the microsatellite locus D13S319, located at 13q14 and telomeric to the RB1 gene, was deleted. Considering other reported cases, our results indicate that submicroscopic deletions accompanying 13q14 translocations are recurrent cytogenetic aberrations in MDS. The RB1 gene or another tumor suppressor gene in the vicinity of D13S319, or both, may be involved in the pathogenesis of MDS with 13q14 translocations by monoallelic deletion.  相似文献   
993.
This study investigated inhibitory factors in anger expressive behaviors among Japanese junior high school students. It also examined the relations between anger experiences and personality traits: verbal expression and narcissism. The result indicated that the factors of "friend relationships" and "cost-reward consciousness" were selected as those which inhibited anger expressive behaviors. Results of a covariance structure analysis were as follows. First, narcissistic personality elicited feelings of anger and depression and cognitions of inflating and calming, which all facilitated aggressive behavior, social sharing, and object-displacement as anger expressive behaviors. Second, verbal expression elicited cognitions of objectifying and self-reproaching, and the former inhibited anger expressive behaviors, though the latter facilitated them. Finally, "cost-reward consciousness" inhibited anger expressive behaviors for boys, while "normative consciousness" inhibited them for girls.  相似文献   
994.
995.
Hematopoietic cytokines such as interleukin (IL)-3, IL-5, and granulocyte macrophage colony-stimulating factor (GM-CSF) play a fundamental role in eosinophil functions in allergic asthma. The intracellular signal transduction mechanisms of these cytokines regulating the activation of eosinophils have been potential therapeutic targets. We investigated the roles of p38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-kappaB) in IL-3, IL-5, and GM-CSF-induced adhesion, morphological changes, and subsequence transmigration of human eosinophils. IL-3, IL-5, and GM-CSF could augment the phosphorylation of p38 MAPK and nucleus translocation of NF-kappaB in eosinophils. cDNA expression arrays demonstrated that the gene expression levels of several adhesion molecules including intercellular adhesion molecule-1 (ICAM-1), alpha6, beta2 integrin (CD18), and CD44 were upregulated by these cytokines. Results from functional assays showed that adhesion of eosinophils onto airway epithelial cells was enhanced after IL-3 and IL-5 but not GM-CSF stimulation. These cytokines could markedly induce shape change and augment the transmigration of eosinophils. Moreover, administration of either p38 MAPK inhibitor, SB 203580, or proteasome inhibitor, N-cbz-Leu-Leu-leucinal (MG-132), could inhibit the cytokine-induced adhesion, shape change, and transmigration of eosinophils. Together, our findings suggest that IL-3, IL-5, and GM-CSF regulated the adhesion and chemotaxis of human eosinophils through shared signaling pathways involving both p38 MAPK and NF-kappaB. Our results therefore shed light on the further development of more effective agents for allergic and inflammatory diseases.  相似文献   
996.
Parkinson's disease is a common neurodegenerative disease that shows not only movement disorder, but also profound urinary dysfunction. Bladder hyperactivity is the major urodynamic abnormality. Therefore, the basal ganglia have been thought to modulate the micturition reflex. In six male adult cats under ketamine anesthesia, in which spontaneous isovolumetric micturition reflexes had been generated, we measured levels of striatal dopamine, in micturition and storage phases, using in vivo microdialysis. The striatal dopamine level significantly increased in the storage phase as compared with that in the micturition phase. It is suggested that striatal dopamine may inhibit the micturition reflex via the dopamine D1 receptor-GABAergic direct striatal output pathway, and that disruption of this pathway may be what leads to bladder hyperactivity in patients with Parkinson's disease.  相似文献   
997.
A major goal of current human genome-wide studies is to identify the genetic basis of complex disorders. However, the availability of an unbiased, reliable, cost efficient and comprehensive methodology to analyze the entire genome for complex disease association is still largely lacking or problematic. Therefore, we have developed a practical and efficient strategy for whole genome association studies of complex diseases by charting the human genome at 100 kb intervals using a collection of 27,039 microsatellites and the DNA pooling method in three successive genomic screens of independent case-control populations. The final step in our methodology consists of fine mapping of the candidate susceptible DNA regions by single nucleotide polymorphisms (SNPs) analysis. This approach was validated upon application to rheumatoid arthritis, a destructive joint disease affecting up to 1% of the population. A total of 47 candidate regions were identified. The top seven loci, withstanding the most stringent statistical tests, were dissected down to individual genes and/or SNPs on four chromosomes, including the previously known 6p21.3-encoded Major Histocompatibility Complex gene, HLA-DRB1. Hence, microsatellite-based genome-wide association analysis complemented by end stage SNP typing provides a new tool for genetic dissection of multifactorial pathologies including common diseases.  相似文献   
998.
Although embryo screening by preimplantation genetic diagnosis (PGD) has become the standard technique for the treatment of recurrent pregnancy loss in couples with a balanced gross chromosomal rearrangement, the implantation and pregnancy rates of PGD using conventional fluorescence in situ hybridization (FISH) remain suboptimal. Comprehensive molecular testing, such as array comparative genomic hybridization and next‐generation sequencing, can improve these rates, but amplification bias in the whole genome amplification method remains an obstacle to accurate diagnosis. Recent advances in amplification procedures combined with improvements in the microarray platform and analytical method have overcome the amplification bias, and the data accuracy of the comprehensive PGD method has reached the level of clinical laboratory testing. Currently, comprehensive PGD is also applied to recurrent pregnancy loss due to recurrent fetal aneuploidy or infertility with recurrent implantation failure, known as preimplantation genetic screening. However, there are still numerous problems to be solved, including misdiagnosis due to somatic mosaicism, cell cycle‐related background noise, and difficulty in diagnosis of polyploidy. The technology for comprehensive PGD also requires further improvement.  相似文献   
999.
1000.
Contribution of polymorphism of transporter associated with antigen processing 1 and 2 (TAP1 and 2) alleles to pathogenesis of Japanese rheumatoid arthritis (RA) was studied in 92 RA patients by PCR-RFLP. The allele frequency of TAP2A was slightly low (38.0%) and the frequencies of TAP2B and TAP2C were slightly high (39.7% and 17.9%) in RA, but these differences were not significant. These increases and decrease were due to the positive or negative associations with HLA-DRB1*0405. It was very likely that slight differences in TAP2A, TAP2B and TA2C in RA were secondary phenomenon reflecting an increase in HLA-DRB1*0405. The prevalence of TAP2E allele was low (3.3%, P <0.01, Pc=not significant) and not correlated with HLA-DRB1*0405.  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