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   35707篇
  免费   2689篇
  国内免费   905篇
耳鼻咽喉   536篇
儿科学   499篇
妇产科学   428篇
基础医学   5826篇
口腔科学   539篇
临床医学   3575篇
内科学   6344篇
皮肤病学   1377篇
神经病学   2483篇
特种医学   2261篇
外国民族医学   2篇
外科学   3927篇
综合类   1475篇
现状与发展   3篇
一般理论   5篇
预防医学   1751篇
眼科学   783篇
药学   3893篇
  2篇
中国医学   879篇
肿瘤学   2713篇
  2024年   44篇
  2023年   358篇
  2022年   1147篇
  2021年   1605篇
  2020年   908篇
  2019年   1184篇
  2018年   1316篇
  2017年   1134篇
  2016年   1482篇
  2015年   1997篇
  2014年   2375篇
  2013年   2467篇
  2012年   3430篇
  2011年   3374篇
  2010年   2065篇
  2009年   1680篇
  2008年   2099篇
  2007年   2007篇
  2006年   1665篇
  2005年   1490篇
  2004年   1247篇
  2003年   1088篇
  2002年   858篇
  2001年   467篇
  2000年   378篇
  1999年   320篇
  1998年   188篇
  1997年   148篇
  1996年   100篇
  1995年   70篇
  1994年   51篇
  1993年   54篇
  1992年   83篇
  1991年   84篇
  1990年   49篇
  1989年   55篇
  1988年   34篇
  1987年   22篇
  1986年   24篇
  1985年   36篇
  1984年   14篇
  1983年   10篇
  1982年   5篇
  1981年   12篇
  1979年   11篇
  1977年   10篇
  1976年   7篇
  1974年   6篇
  1973年   5篇
  1963年   4篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
The application of molecular techniques to solid tumors   总被引:1,自引:0,他引:1  
Recent developments in the field of molecular biology including the sequencing of the human genome and related high throughput methodologies are presenting the diagnostic pathologist with new opportunities to expand our understanding of human disease. These techniques enable the comprehensive assessment of molecular alterations with cell populations of interest, including cancer. It will be necessary for the diagnostic pathologist to become familiar with these techniques to effectively translate their potential into the clinical environment.  相似文献   
72.
Calcium channel blocker is useful for a variety of purposes and is effective for preventing hepatitis elicited by different inducers, suggesting its possible clinical application for treating hepatitis. The alpha1-subunit of the dihydropyridine-sensitive L-type calcium channel is a target of calcium channel blocker. For clinical application of calcium channel blocker, it is important to analyze the expression of the L-type calcium channel in the liver. However, the subtype of the L-type calcium channel alpha1-subunit expressed in the liver was not known. In the present study, the alpha1-subunit of the calcium channel expressed in human liver was systematically analyzed. The alpha1D subunit of the dihydropyridine-sensitive L-type voltage gated calcium channel is expressed relatively strongly in the liver and may play an important role in the liver.  相似文献   
73.
Lamivudine, a nucleoside analogue, has been used widely as an effective antiviral agent for the treatment of patients with chronic hepatitis B virus (HBV) infection. However, the YMDD motif mutation of HBV polymerase resistant to lamivudine occurs very frequently after long term therapy. We developed an oligonucleotide chip for the detection of YMDD motif mutants resistant to lamivudine and investigated the prevalence of the mutants in patients with chronic HBV infection who had not been treated by lamivudine before. Forty patients who had not been treated with lamivudine were included in this study. Serum samples were tested by the oligonucleotide chips designed for detection of wild-type YMDD motif, M552V and M552I. Samples were confirmed by restriction fragment length polymorphism (RFLP) and direct sequencing. M552I mutants were detected by the oligonucleotide chips in 7.5% (3/40) of chronic HBV infected patients (2 chronic hepatitis and 1 cirrhosis). The results were in accordance with those of RFLP. YMDD motif mutants occur as natural genome variabilities in patients with chronic HBV infection who had not been treated with lamivudine before. Oligonucleotide chip technology is a reliable and useful diagnostic tool for the detection of mutants resistant to antiviral therapy in chronic HBV infection.  相似文献   
74.
The effects of different molecular weights of hyaluronic acid (HA), a major component of extracellular matrix, on gap junctional intercellular communication (GJIC) in normal human dermal fibroblasts (NHDF cells) were investigated. NHDF cells were cultured for 4 days with different molecular weights of HA and then the extent of GJIC was assessed by the scrape-loading dye transfer method, using Lucifer yellow. The area of dye transfer was greater in the dishes coated with HA than in those to which HA was added. Thus, NHDF cells cultured on surfaces coated with high molecular weight (HMW) HA (MW, 800 kDa) showed greatly enhanced GJIC. Furthermore, another aim of this study was to evaluate the effects of different molecular weights of HA on the production of FGF-2 and KGF, because both are important cytokines produced by NHDF cells. When FGF-2 and KGF cultured levels of cell extracts and media were determined by ELISA, both levels were significantly enhanced when cells were grown on plates coated with HMW HA. This finding indicated that the function of gap junction channels in NHDF cells grown on plates coated with HMW HA may promote the biosynthesis of growth factors such as FGF-2 and KGF.  相似文献   
75.
掌背动脉皮瓣的应用解剖   总被引:4,自引:0,他引:4  
目的:手指软组织损伤,使用手背动脉皮瓣进行修复,手术简单,转移方便,并能很好满足手指修复中对于弹性,厚度,韧度,感觉和活动功能等诸多要求,方法:43只上肢标本,色素动脉灌注,解剖掌背动脉及分支,结果:观测掌背动脉起源,形态,分支吻合,管径,并计算各吻合点的自比例定位,结论;提出掌背动脉轴形皮瓣应用范围及可行性,为临床提供解剖学资料和手术操作要点。  相似文献   
76.
Although acquired mutations in the GATA1 gene have been reported for Down syndrome-related acute megakaryoblastic leukemia (DS-AMKL) in Caucasians, this is the first report of a Korean Down syndrome patient with AMKL carrying a novel mutation of the GATA1 gene. A 3-yr-old Korean girl with Down syndrome was admitted to our hospital complaining of pallor and fever. The findings of a peripheral blood smear and bone marrow study were compatible with the presence of AMKL. A chromosome study showed 48,XX,-7,+21c,+21,+r[3]/47,XX,+21c[17]. Following GATA1 gene mutation analysis, a novel mutation, c.145dupG (p.Ala49GlyfsX18), was identified in the N-terminal activation domain of the GATA1 gene. This mutation caused a premature termination at codon 67 and expression of an abnormal GATA-1 protein with a defective N-terminal activation domain, and the absence of full-length GATA-1 protein. This case demonstrates that a leukemogenic mechanism for DS-AMKL is contributed by a unique collaboration between overexpressed genes from trisomy 21 and an acquired GATA1 mutation previously seen in Caucasians and now in a Korean patient.  相似文献   
77.
78.
79.
PurposeOral adsorbents delay disease progression and improve uremic symptoms in patients with chronic kidney disease (CKD). DW-7202 is a newly developed oral adsorbent with high adsorptive selectivity for uremic toxins. We evaluated patient preference for and adherence to DW-7202 versus AST-120 therapy and compared treatment efficacy and safety in patients with pre-dialysis CKD.Materials and MethodsA seven-center, randomized, open-label, two-way crossover, active-controlled, phase IV clinical trial was conducted. Patients with stable CKD were randomly assigned to receive DW-7202 (capsule type) or AST-120 (granule type) for 12 weeks. The groups then switched to the other adsorbent and took it for the next 12 weeks. Patient preference was the primary outcome. Secondary outcomes included changes in estimated glomerular filtration rate (eGFR) and serum creatinine, cystatin C, and indoxyl sulfate (IS) levels.ResultsSignificantly more patients preferred DW-7202 than AST-120 (p<0.001). Patient adherence improved after switching from AST-120 to DW-7202; there was no apparent change in adherence after switching from DW-7202 to AST-120. Changes in eGFR and serum creatinine, cystatin C, and IS levels were not significantly different according to adsorbent type. There was also no significant difference in the incidences of adverse events during treatment with DW-7202 and AST-120.ConclusionDW-7202 can be considered as an alternative to AST-120 in patients who cannot tolerate or show poor adherence to granule type adsorbents. Further studies to evaluate factors affecting patient preferences and improved adherence are warranted (Clinical trial registration No. NCT02681952).  相似文献   
80.
The study of the reaction of some methylenebisphenols with chloranil in ethanol and also of a phenol formaldehyde condensate prepared by acid catalysis, reveals that quinone methide is formed in the self-cure of quinoid phenol formaldehyde resin. The quinone methide reacts with ethanol to give an adduct. The structure of the alcohol adduct is identified by NMR and IR data and by means of pyrolysis.  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