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   9179篇
  免费   965篇
  国内免费   14篇
耳鼻咽喉   58篇
儿科学   455篇
妇产科学   264篇
基础医学   1382篇
口腔科学   125篇
临床医学   1214篇
内科学   1663篇
皮肤病学   246篇
神经病学   933篇
特种医学   174篇
外科学   825篇
综合类   229篇
一般理论   21篇
预防医学   1140篇
眼科学   163篇
药学   638篇
中国医学   10篇
肿瘤学   618篇
  2024年   12篇
  2023年   132篇
  2022年   192篇
  2021年   413篇
  2020年   269篇
  2019年   373篇
  2018年   393篇
  2017年   288篇
  2016年   319篇
  2015年   341篇
  2014年   392篇
  2013年   505篇
  2012年   750篇
  2011年   781篇
  2010年   407篇
  2009年   303篇
  2008年   494篇
  2007年   552篇
  2006年   467篇
  2005年   505篇
  2004年   454篇
  2003年   357篇
  2002年   398篇
  2001年   61篇
  2000年   55篇
  1999年   66篇
  1998年   73篇
  1997年   41篇
  1996年   61篇
  1995年   47篇
  1994年   44篇
  1993年   47篇
  1992年   43篇
  1991年   34篇
  1990年   28篇
  1989年   21篇
  1987年   22篇
  1986年   28篇
  1985年   38篇
  1984年   38篇
  1983年   30篇
  1982年   29篇
  1981年   18篇
  1980年   15篇
  1979年   14篇
  1978年   13篇
  1975年   11篇
  1973年   11篇
  1972年   12篇
  1962年   11篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
881.
882.
883.
Minimal (i.e. submicroscopic) residual disease (MRD) predicts outcome in childhood acute lymphoblastic leukaemia (ALL). To be used clinically, MRD assays must be reliable and accurate. Two well-established techniques, flow cytometry (FC) and polymerase chain reaction (PCR), can detect leukaemic cells with a sensitivity of 0.01% (10(-4)). We analysed diagnostic samples of 45 ALL-patients (37 B-lineage ALL, eight T-lineage ALL) by four-colour FC and real-time PCR. Leukaemia-associated immunophenotypes, at a sensitivity of MRD detection by FC at the 0.01% level, were identified in 41 cases (91%); antigen-receptor gene rearrangements suitable for MRD detection with a sensitivity of 0.01% or better by PCR were identified in 38 cases (84%). The combined use of FC and PCR allowed MRD monitoring in all 45 patients. In 105 follow-up samples, MRD estimates by both methods were highly concordant, with a deviation factor of <5 by Bland-Altman analysis. Importantly, the concordance between FC and PCR was also observed in regenerating bone marrow samples containing high proportions of CD19(+) cells, and in samples studied 24 h after collection. We conclude that both MRD assays yield generally concordant results. Their combined use should enable MRD monitoring in virtually all patients and prevent false-negative results due to clonal evolution or phenotypic shifts.  相似文献   
884.
To investigate whether genetic differences in cytokine promoter polymorphisms effect various outcomes after exposure to Epstein-Barr virus (EBV) infection, 30 patients with EBV-positive gastric carcinoma (GC), 120 patients with EBV-negative GC, and 220 control subjects were enrolled. Promoter polymorphisms of tumor necrosis factor (TNF)-alpha at positions -238 and -308 and of interleukin (IL)-10 at position -1082 were determined. The frequency of the high-producer allele (-308A) in the TNF-alpha gene was significantly higher among EBV-positive GC patients compared with control subjects (23.3% vs. 12.0%, P<.05), whereas the frequency of the high-producer allele (-1082G) in the IL-10 gene was significantly higher among EBV-negative GC patients compared with control subjects (6.3% vs. 3.0%, P<.05). These data support the notion that genetic factors may modify the outcomes of infectious diseases through different TNF-alpha- or IL-10-producing capabilities.  相似文献   
885.
Our recent report of dihydroartemisinin-piperaquine failure to treat Plasmodium falciparum infections in Cambodia adds new urgency to the search for alternative treatments. Despite dihydroartemisinin-piperaquine failure, and higher piperaquine 50% inhibitory concentrations (IC50s) following reanalysis than those previously reported, P. falciparum remained sensitive to atovaquone (ATQ) in vitro. There were no point mutations in the P. falciparum cytochrome b ATQ resistance gene. Mefloquine, artemisinin, chloroquine, and quinine IC50s remained comparable to those from other recent reports. Atovaquone-proguanil may be a useful stopgap but remains susceptible to developing resistance when used as blood-stage therapy.  相似文献   
886.
Smartphone technology is being increasingly viewed as key to engaging young adults with schizophrenia in their own mental health care. In an attempt to use smartphones as an engagement tool, we conducted a participatory design process, where young adults with schizophrenia (n = 4), healthcare providers (n = 7), software designers (n = 3), graphic designer (n = 1), graphic recorder (n = 1), and team leader (n = 1) co‐designed a smartphone application for use in early phase schizophrenia care. This paper reports the co‐design process. Based on a variety of written data‐sources, the paper describes if, and how, participatory design can help construct a physical and relational environment that enables young adults with schizophrenia to become active participants in the design of a more participatory mental health practice. Guided by Etienne Wenger's construct of Community of Practice, three major categories of characteristics and construction of a physical and relational environment supporting and inspiring participation and engagement were identified: (i) a pre‐narrative about a community of practice, (ii) the room for design is a community of practice and (iii) the community of practice as a practice of special qualities. It is concluded that participatory design can support and inspire participation and engagement in the development of mental health care with young adults with schizophrenia, given that the environment in which participatory design unfolds is transparent, flexible, secure and informal.  相似文献   
887.
PURPOSE: To analyze fracture risk and bone mineral density in patients with eating disorders (anorexia nervosa, bulimia nervosa, and other eating disorders). DESIGN: Clinical overview. FINDINGS: Bone mineral density is decreased and fracture risk increased in patients with anorexia nervosa. In patients with bulimia nervosa, bone mineral is only marginally decreased and fracture risk marginally increased. In patients with other eating disorders (eating disorders not otherwise specified), bone mineral density is decreased and fracture risk increased. CONCLUSIONS: Fracture risk is increased in patients with eating disorders. An eating disorder should be suspected in severely underweight young individuals (primarily girls) presenting with fractures, especially low-energy fractures.  相似文献   
888.
Junctional epidermolysis bullosa (JEB) is an autosomal recessive skin blistering disease with both lethal and nonlethal forms, with most patients shown to have defects in laminin-5. We analyzed the location of mutations, gene expression levels, and protein chain assembly of the laminin-5 heterotrimer in six JEB patients to determine how the type of genetic lesion influences the pathophysiology of JEB. Mutations within laminin-5 genes were diversely located, with the most severe forms of JEB correlating best with premature termination codons, rather than mapping to any particular protein domain. In all six JEB patients, the laminin-5 assembly intermediates we observed were as predicted by our previous work indicating that the α3β3γ2 heterotrimer assembles intracellularly via a β3γ2 heterodimer intermediate. Since assembly precedes secretion, mutations that disrupt protein–protein interactions needed for assembly are predicted to limit the secretion of laminin-5, and likely to interfere with function. However, our data indicate that typically the most severe mutations diminish mRNA stability, and serve as functional null alleles that block chain assembly by resulting in either a deficiency (in the nonlethal mitis variety) or a complete absence (in lethal Herlitz-JEB) of one of the chains needed for laminin-5 heterotrimer assembly.  相似文献   
889.
890.

Background

Non-unions of long bone fractures are a therapeutic and economic problem of increasing frequency. Aside from conservative treatment options such as ultrasound, impulse waves, and casts, the basic surgical options are autogenous cancellous bone grafting, rod dynamization, reamed nailing, plate fixation, and bone transport techniques. If these methods fail to work, there is a need for alternative treatment options.

Methods

Since May 2001, treatment with recombinant human bone morphogenic protein 7 (BMP 7 or osteogenic protein 1) in combination with a type-one collagen carrier has been the subject of increasing interest. BMP 7 induces the formation of new bone by stem cell differentiation, thereby initiating the reaction cascade of osteogenesis. Non-unions over 9 months and unsuccessful bone grafting constitute the indication for this treatment.

Results

We report our experience with 54 patients who had atrophic non-union of long bone fractures. Between May 2002 and May 2006, 57 units of BMP 7 were used. The localization of the non-unions included 21 in the femur, 26 in the tibia, 3 in the humerus and 7 in the forearm. In 36 cases, BMP 7 was used in combination with osteosynthesis revision and bone grafting; in 9 additional patients, BMP 7 was used with bone grafting alone. In 12 patients, BMP 7 was applied as a single procedure without any bone grafting or any change in osteosynthesis.

Conclusions

There were no perioperative or postoperative complications. Follow-up was obtained for a minimum of 6 months. 47 of the 57 (82%) implantations were successful, with bony healing confirmed by clinical and radiological evaluation. In summary, our results support BMP 7 as an additional innovative therapy for long bone non-unions.  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