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   3393篇
  免费   228篇
  国内免费   9篇
耳鼻咽喉   62篇
儿科学   129篇
妇产科学   37篇
基础医学   499篇
口腔科学   64篇
临床医学   321篇
内科学   665篇
皮肤病学   100篇
神经病学   274篇
特种医学   70篇
外科学   611篇
综合类   18篇
一般理论   31篇
预防医学   296篇
眼科学   32篇
药学   149篇
中国医学   2篇
肿瘤学   270篇
  2022年   23篇
  2021年   37篇
  2020年   33篇
  2019年   38篇
  2018年   64篇
  2017年   54篇
  2016年   65篇
  2015年   71篇
  2014年   78篇
  2013年   125篇
  2012年   162篇
  2011年   152篇
  2010年   105篇
  2009年   100篇
  2008年   172篇
  2007年   172篇
  2006年   168篇
  2005年   167篇
  2004年   152篇
  2003年   151篇
  2002年   146篇
  2001年   66篇
  2000年   55篇
  1999年   73篇
  1998年   52篇
  1997年   49篇
  1996年   47篇
  1995年   49篇
  1994年   32篇
  1993年   30篇
  1992年   50篇
  1991年   62篇
  1990年   49篇
  1989年   50篇
  1988年   59篇
  1987年   40篇
  1986年   41篇
  1985年   35篇
  1984年   34篇
  1983年   45篇
  1982年   34篇
  1981年   33篇
  1979年   33篇
  1978年   23篇
  1977年   22篇
  1976年   27篇
  1974年   22篇
  1971年   21篇
  1970年   21篇
  1967年   23篇
排序方式: 共有3630条查询结果,搜索用时 18 毫秒
81.
82.
OBJECTIVE: This study explored whether the Pro12Ala polymorphism in the peroxisome proliferator-activated receptor-gamma (PPARgamma) is associated with blood pressure in subjects with type 2 diabetes. DESIGN: A community-based, cross-sectional observation study. SETTING: Primary care. PATIENTS: One hundred and ninety-two men and 192 women with type 2 diabetes who consecutively underwent annual follow-up. MAIN OUTCOME MEASURE: The PPARgammaPro12Ala genotype was determined by polymerase chain reaction-based techniques. Associations between genotype and blood pressure were analysed by linear regression and expressed as differences in blood pressure (delta) with 95% confidence interval (CI). RESULTS: The mean systolic blood pressure and the diastolic blood pressure were 160 mmHg (standard deviation = 22.8) and 84 mmHg (standard deviation = 9.6), respectively. Subjects with Pro/Ala (24%) or Ala/Ala (2%) had lower diastolic blood pressure (delta = 2.8; 95% CI, 0.6-5.0) when adjusted for age and gender compared with Pro/Pro subjects (74%). This association was restricted to men (delta = 4.4; 95% CI, 1.3-7.4), who also had a borderline significant difference in systolic blood pressure (delta = 6.9; 95% CI, -0.8 to 13.8). In men the difference in diastolic blood pressure remained after adjustment for age, body mass index, serum triglycerides, serum insulin and haemoglobin A(1c) (delta = 4.6; 95% CI, 1.1-8.1). A subanalysis of normotensive men (n = 100) confirmed the difference associated with the Pro12Ala polymorphism in diastolic blood pressure (delta = 5.2; 95% CI, 0.6-10.0). CONCLUSIONS: The common Pro12Ala polymorphism in PPARgamma is associated with lower diastolic blood pressure in male subjects with type 2 diabetes.  相似文献   
83.
The association between various human leucocyte antigen (HLA) alleles and the occurrence of acute and chronic graft-versus-host disease (GVHD) was evaluated in 493 haematopoietic stem-cell transplant (HSCT) patients with HLA identical sibling donors. There were 307 men and 186 women with a median age of 30 years (0.2-77). Most of the patients had a haematological malignancy and received total body irradiation or busulphan combined with cyclophosphamide as conditioning before transplantation. GVHD prophylaxis consisted of monotherapy with methotrexate (MTX) or cyclosporin (CsA) in 118 patients, MTX + CsA in 323, T-cell depletion in 28 and other combinations in 24. In total, 84 patients (17%) received a peripheral blood stem-cell graft, whereas the rest received bone marrow. The cumulative incidence of acute GVHD grades II-IV was 20%, and chronic GVHD 46%. In the multivariate analysis, HLA-A10 (OR 2.14, CI 1.04-4.41, P = 0.03) and HLA-B7 (OR 1.80, CI 1.04-3.12, P = 0.03) correlated with an increased risk of acute GVHD grades II-IV. We also found an association between HLA-B27 (RR 0.60, CI 0.37-0.95, P = 0.04) and a lower incidence of chronic GVHD. These HLA alleles were independent of other known risk factors for acute or chronic GVHD, as shown by multivariate analysis. These results show that major histocompatibility comlex (MHC) alleles may influence the incidence of GVHD in HSCT with HLA identical sibling donors.  相似文献   
84.
85.
Diagnostic differentiation of pathogenic Entamoeba histolytica from non-pathogenic Entamoeba dispar is of great clinical importance. We have developed and evaluated a new polymerase chain reaction (PCR) assay (haemo-PCR) based on the novel E. histolytica hemolysin gene HLY6. The specificity of this assay was confirmed by analyzing different Entamoeba species, faeces samples, human and bacterial DNA, and digestion of amplification products with appropriate restriction enzymes. The sensitivity was confirmed by serial dilutions of E. histolytica HM-1:IMSS DNA in the excess of human DNA. Totally, 45 clinical samples were analyzed by the haemo-PCR assay including amoebic liver abscess (ALA) fluids from 23 patients suspected for amoebiasis, four faeces samples containing E. histolytica and E. dispar, and positive and negative controls. The results were compared with those obtained with PCRs for cystein-rich surface protein (P30) and small subunit ribosomal RNA (ssu rRNA) genes. The haemo-PCR gave a positive result in 18 (89%) ALA fluids compared with 14 (77%) and five (28%) by PCR for p30, and ssu rRNA, respectively. PCR products were obtained only from specimens containing E. histolytica DNA. The haemo-PCR assay was therefore found to be a valuable diagnostic tool for identification of E. histolytica infections both in faeces and ALA samples.  相似文献   
86.
Genome-wide association studies have identified a number of susceptibility loci in sporadic Parkinson's disease (PD). Recent larger studies and meta-analyses have greatly expanded the list of proposed association signals. We performed a case-control replication study in a Scandinavian population, analyzing samples from 1345 unrelated PD patients and 1225 control subjects collected by collaborating centers in Norway and Sweden. Single-nucleotide polymorphisms representing 18 loci previously reported at genome-wide significance levels were genotyped, as well as 4 near-significant, suggestive, loci. We replicated 11 association signals at p < 0.05 (SNCA, STK39, MAPT, GPNMB, CCDC62/HIP1R, SYT11, GAK, STX1B, MCCC1/LAMP3, ACMSD, and FGF20). The more recently nominated susceptibility loci were well represented among our positive findings, including 3 which have not previously been validated in independent studies. Conversely, some of the more well-established loci failed to replicate. While future meta-analyses should corroborate disease associations further on the level of common markers, efforts to pinpoint functional variants and understand the biological implications of each risk locus in PD are also warranted.  相似文献   
87.
Angiogenesis is an important physiological and pathological process. Bartonella is the only genus of bacteria known to induce pathological angiogenesis in the mammalian host. Bartonella-induced angiogenesis leads to the formation of vascular tumors including verruga peruana and bacillary angiomatosis. The mechanism of Bartonella-induced angiogenesis is not completely understood. Pericytes, along with endothelial cells, play an important role in physiological angiogenesis, and their role in tumor angiogenesis has been extensively studied. Abnormal signaling between endothelial cells and pericytes contributes to tumor angiogenesis and metastasis; however, the role of pericytes in Bartonella-induced angiogenesis is not known. In this study, after infecting human brain vascular pericytes (HBVPs) with Bartonella henselae, we found that these bacteria were able to invade HBVPs and that bacterial infection resulted in decreased pericyte proliferation and increased pericyte production of vascular endothelial growth factor (VEGF) when compared to the uninfected control cells. In the context of pathological angiogenesis, reduced pericyte coverage, accompanied by increased VEGF production, may promote endothelial cell proliferation and the formation of new vessels.  相似文献   
88.
89.
Pancreatic islet transplantation is a treatment option for patients with type 1 diabetes (T1D), but pregnancy has generally not been advised for women after receiving an islet allograft. We hereby describe what is to our knowledge the first successful pregnancy and persistent graft function in a woman 4 years after her initial islet transplantation. A 37‐year‐old woman with brittle type 1 diabetes was transplanted with two separate islet graft infusions, eventually becoming insulin independent. Ten months after her second transplantation, her immunosuppression was switched from tacrolimus and sirolimus to tacrolimus, azathioprine, and prednisolone, due to her wish to become pregnant. She became pregnant one year later, and after 38 weeks of uncomplicated pregnancy, she gave birth to a healthy child by C‐section. The current report suggests that pregnancy and childbirth can be accomplished after islet transplantation without loss of islet graft function.  相似文献   
90.
In this single-center study, we retrospectively analyzed incidenceand risk factors for hepatic veno-occlusive disease (VOD) in 249 consecutive patients who underwent allogeneic hematopoietic stem celltransplantation between January 1990 and June 1995. Twenty-four of the249 transplanted patients developed VOD. The probabilities ofdeveloping VOD were 17% among women and 7% in men (P = .01). In women treated with norethisterone, the incidence was 27%compared with 3% in women without this treatment (P = .007).One-year survival rates were 17% and 73% in patients with (n = 24)or without VOD (n = 225), respectively. The use of heparin prophylaxis (100 IE/kg/24 hours for 1 month) did not alter the incidence or 1-year mortality of VOD. In multivariate analysis, thefollowing risk factors were significant: norethisterone treatment (P < .001), bilirubin >26 µmol/L before bone marrowtransplantation (BMT) (P = .002), one HLA-antigen mismatch(P = .003), previous abdominal irradiation (P = .02), and conditioning with busulphan (P = .02). Ourconclusion is that norethisterone treatment should not be used inpatients undergoing BMT and heparin prophylaxis did not affect theincidence or mortality of VOD.  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