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   843篇
  免费   55篇
  国内免费   1篇
耳鼻咽喉   6篇
儿科学   46篇
妇产科学   9篇
基础医学   158篇
口腔科学   16篇
临床医学   82篇
内科学   166篇
皮肤病学   32篇
神经病学   74篇
特种医学   21篇
外科学   54篇
综合类   9篇
一般理论   3篇
预防医学   66篇
眼科学   35篇
药学   82篇
中国医学   1篇
肿瘤学   39篇
  2024年   2篇
  2023年   10篇
  2022年   23篇
  2021年   43篇
  2020年   19篇
  2019年   25篇
  2018年   31篇
  2017年   9篇
  2016年   20篇
  2015年   30篇
  2014年   29篇
  2013年   47篇
  2012年   74篇
  2011年   48篇
  2010年   35篇
  2009年   23篇
  2008年   51篇
  2007年   67篇
  2006年   52篇
  2005年   38篇
  2004年   38篇
  2003年   36篇
  2002年   36篇
  2001年   14篇
  2000年   6篇
  1999年   8篇
  1998年   8篇
  1997年   4篇
  1996年   6篇
  1995年   2篇
  1994年   4篇
  1993年   4篇
  1989年   3篇
  1988年   4篇
  1987年   2篇
  1986年   3篇
  1984年   4篇
  1981年   2篇
  1978年   2篇
  1976年   2篇
  1973年   2篇
  1933年   5篇
  1931年   2篇
  1929年   1篇
  1928年   1篇
  1927年   1篇
  1925年   3篇
  1922年   1篇
  1912年   2篇
  1911年   1篇
排序方式: 共有899条查询结果,搜索用时 15 毫秒
51.
52.
A retrospective review of an outbreak of community-acquired methicillin-resistant Staphylococcus aureus soft tissue infections in a high school football team was conducted. Thirteen players had 20 infections. Available community-acquired methicillin-resistant S. aureus isolates showed identical antibiotic susceptibility and field inversion gel electrophoresis analysis band patterns. Nasal cultures and mupirocin were ineffective at predicting and controlling infection, respectively. Infections treated with beta-lactam antibiotics were at risk for recurrence.  相似文献   
53.
Purpose: To develop inhouse made (IHM) embryo culture medium with a Multipurpose Isolator and compare the embryo development in a prospective randomized study with commercial media.Methods: Fertilization by intracytoplasmic single sperm injection (ICSI) of Metaphase II oocytes obtained after 96 controlled ovarian hyperstimulation cycles in patients not older than 37 years. Transfer of zygotes to IHM or commercial Cook Sydney IVF Cleavage medium (SIC) immediately after pronucleus observation. Evaluation of embryo cleavage and score, pregnancy, and implantation rate.Results: From 100 zygotes cultured in SIC, 61% were at the 4 cell stage 45 h after ICSI compared to 77% (78/101) in the IHM, P<0.05. The mean embryo score with IHM was 3.9±0.9 compared to 3.5±1.2 with SIC, P<0.05. The clinical pregnancy rate per transfer was 38.9% (37/95), the implantation rate was 23% (46/200), and no differences were observed between the groups.  相似文献   
54.
Mutations in the connexin 26 (Cx26) gene (GJB2) are a common cause of hereditary hearing impairment which affects approximately 1 in 2000 newborn children. We report the identification of a novel Cx26 point mutation (439 G-->A) linked to familial, autosomal recessive, sensorineural hearing loss. This missense mutation (E147K) is located in the highly conserved, putative K(+) channel lining sequence of the third transmembrane domain (TM3) of Cx26. Hearing impairment associated with this mutation was congenital, moderate to profound and showed no signs of progressive deterioration.  相似文献   
55.
BACKGROUND: Immunosuppressive agents are at the forefront of preventing organ rejection after transplantation. However, their effects on vascular smooth muscle cell-mediated intimal hyperplasia that occurs in post-transplant coronary artery disease are less well known. METHODS AND RESULTS: We investigated the in vitro effects of three immunosuppressive agents cyclosporine A (CsA), FK506 (tacrolimus), and rapamycin (sirolimus, Rapa) on cultured human coronary artery smooth muscle cells (cSMC). CsA inhibited both platelet-derived growth factor (PDGF)-stimulated DNA synthesis and serum-induced proliferation at high concentrations (> or =1000 ng/ml). The growth-inhibitory effect of CsA was not altered by anti-TGF-beta neutralising antibodies nor was autocrine TGF-beta release detected in CsA-treated culture medium. At inhibitory doses, CsA inhibited ERK kinase activation by PDGF, although cytotoxicity was also apparent. Most notably, CsA visibly prevented PDGF-induced altered cell morphology. Rapa was a highly potent and effective inhibitor of cSMC proliferation (reduction in DNA synthesis by >50% from 0.01 ng/ml), acting through inhibition of 70-kDa S6 kinase (p70S6k). FK506 (1-1000 ng/ml) did not affect cSMC proliferation alone, although a > or =250-fold excess of FK506 over Rapa completely reversed the inhibitory effect of Rapa, confirming that these two agents share a common intracellular receptor, the FK506-binding protein (FKBP). CONCLUSION: Rapa is a powerful inhibitor of cSMC proliferation, while CsA slighly inhibits cSMC proliferation, although only at higher concentrations that may be toxic. These results indicate that therapeutic immunosuppression with Rapa may be additionally useful in prevention or delay of posttransplant coronary artery disease.  相似文献   
56.
Recent data indicate that the apoptotic process, mediated by the CD95/Fas cell surface receptor, is impaired in activated lymphocytes of patients with relapsing-remitting multiple sclerosis. Using flow cytometric-immunophenotyping, we analyzed the expression of CD95/Fas on peripheral blood CD4+ and CD8+ T lymphocytes (PBL) in 10 MS patients in relapse, and the effect of pulse corticosteroid therapy on the apoptosis of autoreactive lymphocytes. The proportions of CD8+ and CD8+CD95+ T lymphocytes were significantly higher in MS patients in relapse before than after pulse corticosteroid therapy. Conversely, the proportions of CD4+ and CD4+CD95+ T cells were significantly lower before than after therapy, but not significantly different from healthy persons. The different expression of CD95/Fas on peripheral blood CD8+ T lymphocytes in relapsing RRMS and in healthy controls suggests a possible involvement of apoptosis in the pathogenesis of MS. Our results also show that pulse corticosteroid therapy influences the CD95/Fas expression on CD8+ and CD4+ T lymphocytes in patients with RRMS.  相似文献   
57.
Granulocyte/macrophage-colony stimulating factor (GM-CSF) is a valuable adjuvant to enhance induction of cellular immune responses in rodents. Less information is available regarding its use as an adjuvant in primates or humans. We explored recombinant human GM-CSF for potential vaccine studies in rhesus macaques and focused on its effect on peripheral monocytes as progenitors of dendritic cells and its potential immunogenicity. Application of human GM-CSF to nine animals led to an average 32-fold increase in monocyte numbers. This was not observed upon re-treatment, which coincided with GM-CSF-specific neutralising antibodies. These also neutralised the activity of rhesus macaque GM-CSF. The data underscore the need to use species-specific GM-CSF for immunomodulation in primates.  相似文献   
58.
Chemokines play an important role in leukocyte mobilization, hematopoiesis, and angiogenesis. Tissue-specific expression of particular chemokines also influences tumor growth and metastasis. Here, the CC chemokine pulmonary and activation-regulated chemokine (PARC)/CCL18 was measured in pediatric patients with acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML). Surprisingly, PARC immunoreactivity was consistently detected in plasma from healthy donors. After purification to homogeneity, the presence of intact PARC (1-69) and processed PARC (1-68) in normal human plasma was confirmed by sequence and mass spectrometry analysis. Furthermore, PARC serum levels were significantly increased in children with T-ALL and prepreB-ALL compared to control serum samples, whereas serum levels in AML and preB-ALL patients were not significantly different from controls. In contrast, the hemofiltrate CC chemokine-1 (HCC-1)/CCL14 was not found to be a biomarker in any of these patients' strata, whereas the cytokine interleukin-6 (IL-6) was significantly decreased in AML and prepreB-ALL. Stimulated leukocytic cell lines or lymphoblasts from patients produced IL-8/CXCL8 or macrophage inflammatory protein-1alpha (MIP-1alpha/CCL3) but not PARC, not even after IL-4 or IL-10 treatment. However, PARC was produced by superantigen or IL-4 stimulated monocytes co-cultured with lymphocytes or lymphoblastic cells. Serum PARC levels thus constitute a novel leukemia marker, possibly reflecting tumor/host cell interactions in the circulation.  相似文献   
59.
Guo YX  Wei T  Dallmann K  Kwang J 《Virology》2003,308(1):74-82
Betanodaviruses, members of the Nodaviridae family, are the causative agents of viral nervous necrosis in fish and infection by which cause high mortality in larvae and juveniles in a wide range of marine fish species in Asia, Europe, Australia, Martinique, and Tahit. Greasy grouper (Epinephelus tauvina) nervous necrosis viruses (GGNNV) were investigated for their apoptotic activity in culture cells. GGNNV infection of sea bass (SB) cells appeared to induce a typical cytopathic effect (CPE), i.e., cytoplasmic vacuolation, thinning, rounding up, detachment of infected cells from the cultured dish, and eventually cell lysis and death. The infected SB cells underwent DNA fragmentation and stained positive in terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) assay, suggesting that GGNNV infection induced apoptosis in SB cells. In addition, GGNNV-infected SB cells showed an increased activity of caspase-8-like proteases (IETDase) and caspase-3-like proteases (IETDase), whereas inhibitor of caspase-8 and caspase-3 reduced GGNNV-induced apoptosis. This suggests that GGNNV may promote apoptosis via the extrinsic pathway in SB cells. Protein alpha, the precursor of GGNNV capsid proteins, was transiently expressed in SB and Cos-7 cells. The DNA fragmentation and TUNEL positive signal were apparent in SB and Cos-7 cells expressing protein alpha, suggesting that protein alpha may serve as an apoptotic inducer in these cells. Moreover, expression of protein alpha resulted in the activation of caspase-3-like proteases in both cells, which could be inhibited by a caspase-3-like protease specific inhibitor DEVD-CHO peptide. These results suggest that fish caspases are important elements in GGNNV-meditated apoptosis.  相似文献   
60.
Development of a vaccine for prevention of congenital cytomegalovirus (CMV) disease is a priority. This study evaluated a "prime-boost" strategy by comparing the safety and immunogenicity of 3 doses of subunit CMV glycoprotein B (gB) vaccine plus MF59 (a squalene-in-water emulsion), 2 doses of a canarypox recombinant vaccine expressing CMVgB (ALVAC-CMVgB) followed by 2 doses of the subunit gB vaccine, 3 doses of both vaccines administered concomitantly, and placebo in 105 healthy, CMV-seronegative adults. Systemic adverse events were rare, but local reactions were common in all groups. After the first subunit vaccination, neutralizing antibody titers in the prime-boost group were comparable to those in subjects receiving 2 subunit vaccinations, indicating a priming effect of ALVAC-CMVgB. However, after the final dose, antibody and cell-mediated immune responses were not significantly different among the groups. All 3 vaccine regimens induced high-titer antibody and lymphoproliferative responses, but no benefit for priming or simultaneous vaccination was detected.  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