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   3478篇
  免费   325篇
  国内免费   10篇
耳鼻咽喉   6篇
儿科学   103篇
妇产科学   43篇
基础医学   658篇
口腔科学   49篇
临床医学   401篇
内科学   870篇
皮肤病学   80篇
神经病学   313篇
特种医学   167篇
外科学   370篇
综合类   29篇
一般理论   2篇
预防医学   197篇
眼科学   31篇
药学   203篇
中国医学   5篇
肿瘤学   286篇
  2023年   32篇
  2022年   50篇
  2021年   113篇
  2020年   63篇
  2019年   106篇
  2018年   113篇
  2017年   73篇
  2016年   82篇
  2015年   91篇
  2014年   163篇
  2013年   158篇
  2012年   304篇
  2011年   304篇
  2010年   168篇
  2009年   135篇
  2008年   213篇
  2007年   247篇
  2006年   224篇
  2005年   200篇
  2004年   187篇
  2003年   130篇
  2002年   114篇
  2001年   53篇
  2000年   36篇
  1999年   40篇
  1998年   37篇
  1997年   22篇
  1996年   13篇
  1995年   11篇
  1994年   11篇
  1993年   11篇
  1992年   27篇
  1991年   26篇
  1990年   18篇
  1989年   15篇
  1988年   16篇
  1987年   11篇
  1986年   9篇
  1985年   17篇
  1984年   19篇
  1983年   14篇
  1979年   8篇
  1976年   12篇
  1974年   14篇
  1973年   6篇
  1972年   7篇
  1971年   8篇
  1970年   7篇
  1969年   9篇
  1967年   5篇
排序方式: 共有3813条查询结果,搜索用时 15 毫秒
111.
Postnatal growth from birth up to 7 y of age was evaluated in 151 children with varying degrees of intrauterine growth retardation who were previously examined in their intrauterine life with Doppler velocimetry of the thoracic descending aorta. The children with abnormal fetal aortic blood flow class (BFC), of which 39/46 (85%) had a birthweight > or = 2 SD below the mean of the population, were lean at birth and had a high rate of catch-up growth in weight and length during the first 3 and 6 mo, respectively. After the initial phases of rapid catch-up in weight and length, mean values of SD scores for weight and height remained relatively unchanged up until 2 y of age, thereafter increasing gradually up to 7 y of age, leaving 4/46 (8%) and 4/46 (8%) below -2 SD for weight and height, respectively. The pattern of changes in length/height and weight over time did not differ between those infants with abnormal BFC and those with normal BFC. The abnormal fetal aortic waveform was not related to rate of early catch-up growth or to height or weight at 7 y of age after adjustment for deviation in growth at birth. The magnitude of deficit in weight and length at birth was more predictive of subsequent growth.  相似文献   
112.
Thirty audiotaped and transcribed general practice consultations were used to develop a classification scheme to code the content of doctor-patient communication in primary care. Open coding was used to identify subject matter discussed by general practitioners in consultations featuring commonly presented problems such as respiratory, psychological and musculoskeletal complaints. The classification scheme was found to have an adequate inter-rater reliability (0.72) and was used in a pilot study to code a further 75 consultations featuring psychological problems as the main presenting complaints. Multivariate analysis of variance showed significant relationships between what was discussed by general practitioners and the type of treatment decisions made (F(16, 51) 2.12, p .01). Consultations in which general practitioners talked to their patients about mental coping strategies, social support and treatment options were less likely to end with decisions to prescribe drugs than consultations in which general practitioners did not discuss these subjects.  相似文献   
113.
114.
OBJECTIVE: We studied hypophosphatasia (HP) mutations in 19 cases prenatally detected by ultrasonography without familial history of HP. We correlated the mutations with the reported ultrasound signs, and discussed genetic counseling with regard to the particular dominantly inherited prenatal benign form of HP. METHOD: The coding sequence of the tissue nonspecific alkaline phosphatase (TNSALP) gene was analyzed by DNA sequencing, and 3D modeling was used to locate the mutated amino acids with regard to the functional domains of TNSALP. RESULTS: Although reported ultrasound signs were heterogeneous, two mutated alleles were found in 18 of the 19 cases studied, indicating recessive transmission of the disease. Functional domains of TNSALP were affected by 74% of missense mutations. In all the cases, including one with only a heterozygous mutation, molecular, biological, and familial data do not corroborate the hypothesis of prenatal benign HP. The mutation c.1133A>T observed in the prenatal benign form of HP and common in USA was not found in this series. CONCLUSION: The results point out the prenatally detectable allelic heterogeneity of HP. The nature of the detected mutations and the evidence of recessive inheritance do not support these cases being affected with prenatal benign HP.  相似文献   
115.
The classification of thalidomide as an orphan drug with anti-inflammatory actions has led to its off-label use in conditions refractory to other medications. Although the observed clinical effects of thalidomide suggest it to have immunomodulatory capabilities, the mechanism of action is unclear. Here we review both the positive and negative studies of thalidomide at the bench in order to improve our understanding of the possible mechanisms of this drug in treating a variety of diseases at the bedside. Studies on the effects of thalidomide on the innate and adaptive immune system as well as tumorigenesis and angiogenesis are discussed.  相似文献   
116.
117.
Recent in vitro studies have suggested a role for sialylation in chemokine receptor binding to its ligand (Bannert, N., S. Craig, M. Farzan, D. Sogah, N.V. Santo, H. Choe, and J. Sodroski. 2001. J. Exp. Med. 194:1661-1673). This prompted us to investigate chemokine-induced leukocyte adhesion in inflamed cremaster muscle venules of alpha2,3 sialyltransferase (ST3Gal-IV)-deficient mice. We found a marked reduction in leukocyte adhesion to inflamed microvessels upon injection of the CXCR2 ligands CXCL1 (keratinocyte-derived chemokine) or CXCL8 (interleukin 8). In addition, extravasation of ST3Gal-IV(-/-) neutrophils into thioglycollate-pretreated peritoneal cavities was significantly decreased. In vitro assays revealed that CXCL8 binding to isolated ST3Gal-IV(-/-) neutrophils was markedly impaired. Furthermore, CXCL1-mediated adhesion of ST3Gal-IV(-/-) leukocytes at physiological flow conditions, as well as transendothelial migration of ST3Gal-IV(-/-) leukocytes in response to CXCL1, was significantly reduced. In human neutrophils, enzymatic desialylation decreased binding of CXCR2 ligands to the neutrophil surface and diminished neutrophil degranulation in response to these chemokines. In addition, binding of alpha2,3-linked sialic acid-specific Maackia amurensis lectin II to purified CXCR2 from neuraminidase-treated CXCR2-transfected HEK293 cells was markedly impaired. Collectively, we provide substantial evidence that sialylation by ST3Gal-IV significantly contributes to CXCR2-mediated leukocyte adhesion during inflammation in vivo.  相似文献   
118.
Keratitis-Ichthyosis-Deafness (KID) syndrome (OMIM 148210) is a congenital ectodermal defect. KID consists of an atypical ichthyosiform erythroderma associated with congenital sensorineural deafness. A rare form of the KID syndrome is a fatal course in the first year of life due to severe skin lesion infections and septicaemia. KID appears to be genetically heterogeneous and may be caused by mutations in connexin 26 or connexin 30 genes. GJB2 mutations in the connexin 26 gene are the main cause of the disease. Most of the cases caused by GJB2 mutations are sporadic, but dominant transmission has also been described. To date, the rare lethal form of the disease has been only observed in two Caucasian sporadic patients with the GJB2 mutation, with the p.Gly45Glu (G45E) arising de novo. We have reported an African family with dizygotic twins suffering from a lethal form of KID. The dizygosity of the twins was confirmed by microsatellite markers. The two patients were heterozygous for the G45E mutation of GJB2, whereas the mutation was not detected in the two parents. The unusual transmission of the disease observed in this family could be explained by the occurrence of a somatic or more probably a germinal mosaic in one of the parents.  相似文献   
119.
Embryonic stem cell (ESC)-derived hematopoietic stem cells (HSC), unlike HSC harvested from the blood or marrow, are not contaminated by lymphocytes. We therefore evaluated whether ESC-derived HSC could produce islet cell tolerance, a phenomenon termed graft versus autoimmunity (GVA), without causing the usual allogeneic hematopoietic stem cell transplant complication, graft-versus-host disease (GVHD). Herein, we demonstrate that ESC-derived HSC may be used to prevent autoimmune diabetes mellitus in NOD mice without GVHD or other adverse side effects. ESC were cultured in vitro to induce differentiation toward HSC, selected for c-kit expression, and injected either i.v. or intra-bone marrow (IBM) into sublethally irradiated NOD/LtJ mice. Nine of 10 mice from the IBM group and 5 of 8 from the i.v. group did not become hyperglycemic, in contrast to the control group, in which 8 of 9 mice developed end-stage diabetes. All mice with >5% donor chimerism remained free of diabetes and insulitis, which was confirmed by histology. Splenocytes from transplanted mice were unresponsive to glutamic acid decarboxylase isoform 65, a diabetic-specific autoantigen, but responded normally to third-party antigens. ESC-derived HSC can induce an islet cell tolerizing GVA effect without GVHD. This study represents the first instance, to our knowledge, of ESC-derived HSC cells treating disease in an animal model.  相似文献   
120.
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