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   96201篇
  免费   7698篇
  国内免费   3192篇
耳鼻咽喉   495篇
儿科学   3492篇
妇产科学   1235篇
基础医学   15537篇
口腔科学   1343篇
临床医学   10060篇
内科学   20478篇
皮肤病学   1208篇
神经病学   1941篇
特种医学   1405篇
外国民族医学   8篇
外科学   7698篇
综合类   13207篇
现状与发展   22篇
预防医学   16820篇
眼科学   652篇
药学   6525篇
  54篇
中国医学   1828篇
肿瘤学   3083篇
  2024年   199篇
  2023年   1480篇
  2022年   3570篇
  2021年   4395篇
  2020年   4005篇
  2019年   3243篇
  2018年   3222篇
  2017年   3170篇
  2016年   3560篇
  2015年   3989篇
  2014年   6105篇
  2013年   6749篇
  2012年   6049篇
  2011年   6552篇
  2010年   5046篇
  2009年   4626篇
  2008年   4461篇
  2007年   4631篇
  2006年   4297篇
  2005年   3763篇
  2004年   3202篇
  2003年   2786篇
  2002年   2111篇
  2001年   1997篇
  2000年   1633篇
  1999年   1483篇
  1998年   1253篇
  1997年   1224篇
  1996年   1018篇
  1995年   1003篇
  1994年   941篇
  1993年   766篇
  1992年   625篇
  1991年   553篇
  1990年   445篇
  1989年   431篇
  1988年   368篇
  1987年   278篇
  1986年   228篇
  1985年   409篇
  1984年   251篇
  1983年   194篇
  1982年   189篇
  1981年   150篇
  1980年   100篇
  1979年   96篇
  1978年   71篇
  1977年   51篇
  1976年   60篇
  1975年   21篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
51.
Between October 2001 and August 2002, 30 hospital patients became infected or colonised by a multiresistant (including to carbapenems) epidemic strain of Acinetobacter baumannii (AbMR) in a hospital outbreak. This study analysed the risk-factors associated with acquisition of this epidemic strain and investigated the prognosis of patients infected by AbMR, with the aim of elucidating factors which lead to mortality. A case-control study of the acquisition of AbMR in patients infected or colonised in the hospital outbreak was performed. Independent risk-factors leading to death were studied by logistic regression analysis. Multivariate analysis of the risk-factors for colonisation/infection with AbMR revealed an independent association with the presence of an arterial catheter (OR, 1.13; 95% CI, 1.03-1.25) and administration of imipenem as monotherapy (OR, 11.12; 95% CI, 2.33-53.09). Multivariate analysis of the prognostic features leading to mortality revealed a significant association with hypotension or shock (OR, 24.63; 95% CI, 1.56-387.56) at the time of bacterial isolation.  相似文献   
52.
Antibodies against nerve growth factor (NGF) in sera were detected by enzyme-linked immunosorbent assays (ELISA), by their isolation after passage of sera through NGF immunoadsorbent columns and by their specificity to bind and immunoprecipitate mouse NGF as well as to stain by immunohistochemical methods cellular sites of NGF synthesis. Increased levels of anti-NGF antibodies were found in sera of herpes simplex virus (HSV)-infected patients but not in HSV-inoculated rabbits. As HSV latency is known to be promoted by NGF in vitro, these results may suggest that anti-NGF antibodies modulate the cytokine function of NGF and thus might play a role in HSV infection. The biological function of circulating antibodies against NGF, in general, is now open to future investigation.  相似文献   
53.
本文通过免疫荧光(IF)和电镜(EM)技术对新疆出血热(XHF)及流行性出血热(EHF)病毒的生物学特性在Vero E_6及LLC-MK_2两株传代细胞上进行了比较。两种病毒感染两株细胞后免疫荧光染色有两种不同的荧光形态特征,两种病毒对细胞的敏感性明显不同,XHF病毒在LLC-MK_2细胞上感染后6~8天可出现明显的细胞病变,而EHF病毒感染此细胞后则不引起病变。电镜观察到两种病毒在LLC-MK_2细胞中都能形成与布尼病毒相似的形态特征。  相似文献   
54.
Different doses of hepatitis B virus vaccine—prepared by Korea Green Cross Corporation, were given to healthy infants born to HBsAg-negative mothers at birth, 1 and 6 months of age. A dose of 2 μg was administered intradermally in Group A and, in the three other groups, the vaccine was given intramuscularly (i.m.). An adequate follow-up observation was possible for 9 months after birth in 22, 25, 23 and 21 infants in Groups A, B, C and D, respecvely.
Group C (5 μg, i.m.) produced seroconversion most rapidly, showing the highest rate (96%) at 9 months of age. The lowest seroconversion rate (5%) was found at the age of 1 month in Group A subjects, but the rate increased to 91% after a booster dose was given at 6 months of age.
While it can be concluded that a 5 μg i.m. dose of vaccine at 0, 1 and 6 months of age is optimum for the immunization of infants in efficacy and economy, a 2 μg intradermal dose can also be considered as an immunogenic and economical regimen, though the immune response is slower and a special technique is required for immunization.  相似文献   
55.
56.
Summary.  Hepatitis B virus (HBV) circulates in blood as closely related, but genetically diverse molecules called quasispecies. During replication, HBV production may approach 1011 molecules/day, although during peak activity this rate may increase 100–1000 times. Generally, DNA polymerases have excellent fidelity in reading DNA templates because they are associated with an exonuclease which removes incorrectly added nucleotides. However, the HBV-DNA polymerase lacks fidelity and proofreading function partly because exonuclease activity is either absent or deficient. Thus, the HBV genome and especially the envelope gene, is mutated with unusually high frequency. These mutations can affect more than one open reading frame because of overlapping genes. The S gene contains an exposed major hydrophilic region (residues 110–155), which encompasses the 'a' determinant that is important for inducing immunity. Nucleotide substitutions in this region are common and result in reduced binding or failure to detect hepatitis B surface antigen (HBsAg) in diagnostic assays. Adaptive immunity also depends on the recognition of HBsAg by specific antibody and variants pose a threat if they interfere with binding to antibody. Finally, genomic hypervariability allows HBV to escape selection pressures imposed by antiviral therapies, vaccines and the host immune system, and is responsible for creating genotypes, subgenotypes and subtypes.  相似文献   
57.
门诊抽血室医院感染标本检测结果分析   总被引:1,自引:0,他引:1  
目的 :了解门诊抽血室医院内感染情况。方法 :通过对空气培养、医护人员的手、物体表面、使用中的消毒液 4项指标 112 0份标本进行监测分析。结果 :112 0份标本检验结果合格 10 30份 ,合格率 92 % ,不合格标本 90份 ,培养出细菌 87份。结论 :通过监测抽血室的医院感染标本 ,了解了院内感染情况 ,有效地减少和防止了医护人员之间、医患之间以及和家属之间的交叉感染 ,提高了医疗护理质量 ,预防了医院交叉感染的发生。  相似文献   
58.
With the introduction of more potent immunosuppressive agents, rejection has decreased in simultaneous pancreas/kidney transplant (SPK) recipients. However, as a consequence, opportunistic infections have increased. The purpose of this report is to outline the course of SPK patients who developed polyomavirus-associated nephropathy (PVAN). A retrospective review of 146 consecutive SPK recipients from January 1, 1996 to December 31, 2002 was performed. Immunosuppression, rejection and development of PVAN were reviewed. Nine patients were identified. All received induction with either OKT3 or thymoglobulin. Immunosuppression included tacrolimus/cyclosporine, MMF/azathioprine and sirolimus/prednisone. Two patients were treated for kidney rejection prior to the diagnosis of PVAN. Time to diagnosis was an average of 359.3 days post-transplantation. Immunosuppression was decreased but five ultimately lost function. However, none developed pancreatic abnormalities as demonstrated by normal glucose and amylase. Two underwent renal retransplantation after PVAN diagnosis and both have normal kidney function. PVAN was the leading cause of renal loss in SPK patients in the first 2 years after transplantation and is a serious concern for SPK recipients. The pancreas, however, is spared from evidence of infection, and no pancreatic rejection occurred when immunosuppression was decreased.  相似文献   
59.
加替沙星序贯治疗下呼吸道细菌感染的药物经济学评价   总被引:3,自引:1,他引:2  
郑咏池  魏祖珊 《西部医学》2005,17(5):473-474
目的对加替沙星序贯治疗下呼吸道细菌感染进行药物经济学评价。方法将69例下呼吸道细菌性感染患者,随机分为A组(34例)、B组(35例),其中A组采用加替沙星注射液400mg静脉滴注,每天1次,连用10天;B组先用加替沙星注射液400mg静脉滴注,每天1次,3—4天后改为口服400mg,每天1次,连用6—7天,然后对两种方案进行成本-效果分析。结果两组在临床疗效、不良反应发生率及细菌清除率方面差异无统计学意义(P〉0.05);但A组的医疗费用却高于B组(P〈0.01)。结论加替沙星序贯疗法与单纯静脉滴注相比更安全,更经济合理。  相似文献   
60.
The correlation between microscopic changes with cellular localization of viral antigens was studied in the ileum of 16 cases infected with bovine viral diarrhea virus (BVDV). Microscopic lesions in the ileum included multifocal erosive and ulcerative ileitis, severe congestion and hemorrhage, crypt dilation and mucus engorgement, epithelial debris and leukocytes, lymphoid depletion of Peyer’s patches, herniation of mucosal epithelium into depleted Peyer’s patches, and fibrinoid vasculitis of submucosal vessels. BVDV antigen was detected by immunohistochemistry in macrophages, dendritic cells, smooth muscle cells, endothelial cells, epithelial cells of crypts, and mucosal epithelium, together with other mononuclear cells including lymphocytes, plasma cells, fibroblasts, and intramural ganglial cells. No consistent correlation between the presence of BVDV antigen and vascular lesions in the ileum was identified. The intensity and distribution of the immunoperoxidase stain in the ileum was graded as highly positive (18.7%), moderately positive (56.3%), and mildly positive (25%). In conclusion, the pattern and density of distribution and localization of BVDV antigen in the ileum was not consistently correlated with the severity of microscopic lesions.  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