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   68305篇
  免费   6707篇
  国内免费   4176篇
耳鼻咽喉   214篇
儿科学   1650篇
妇产科学   383篇
基础医学   4176篇
口腔科学   115篇
临床医学   7254篇
内科学   23584篇
皮肤病学   331篇
神经病学   440篇
特种医学   3353篇
外国民族医学   18篇
外科学   9001篇
综合类   11556篇
现状与发展   20篇
预防医学   2441篇
眼科学   152篇
药学   5902篇
  30篇
中国医学   4434篇
肿瘤学   4134篇
  2024年   241篇
  2023年   1528篇
  2022年   2343篇
  2021年   3086篇
  2020年   3090篇
  2019年   2724篇
  2018年   2525篇
  2017年   2802篇
  2016年   3230篇
  2015年   2960篇
  2014年   4710篇
  2013年   4674篇
  2012年   3866篇
  2011年   4355篇
  2010年   3363篇
  2009年   3328篇
  2008年   3334篇
  2007年   3365篇
  2006年   3349篇
  2005年   2771篇
  2004年   2222篇
  2003年   1920篇
  2002年   1699篇
  2001年   1540篇
  2000年   1255篇
  1999年   1050篇
  1998年   1027篇
  1997年   874篇
  1996年   783篇
  1995年   651篇
  1994年   637篇
  1993年   514篇
  1992年   458篇
  1991年   387篇
  1990年   325篇
  1989年   294篇
  1988年   249篇
  1987年   202篇
  1986年   175篇
  1985年   195篇
  1984年   168篇
  1983年   109篇
  1982年   136篇
  1981年   115篇
  1980年   98篇
  1979年   87篇
  1978年   82篇
  1977年   69篇
  1976年   88篇
  1975年   34篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
To examine the effect of colchicine on ethionine induced fatty liver, adult female rats were starved overnight and then injected i.p. with 1 g kg ethionine at 11th hour of fasting; then a half of the rats were also injected i.p. with 2.5 mg kg colchicine twice at 3 and 6 h after the single administration of ethionine. Similarly, fasted control rats were injected i.p. with vehicle alone at the above times. All of the rats were sacrificed after a 20 h fast, and the hepatocytes in periportal areas were observed ultra-structurally. In addition, total lipids in the liver tissue were extracted and determined biochemically. Although similar significant increases of triglyceride were observed in the liver tissue of all ethionine-injected rats, the hapatocytes in the group treated with both chemicals had fewer cytoplasmic fat globules (CFG) than those in the group treated with ethionine only. On the other hand, the diameters of markedly increased membrane-bound lipid particles (MLP) in the double treated group were distributed mainly in the range 0.2–0.4 μm, compared with those (0.1-0.2 μm) in the other groups. These findings indicate that colchicine inhibits the development of CFG in ethionine injured hapatocytes. Acta Pathol Jpn 39: 281∼288, 1989.  相似文献   
62.
The OPAR mouse monoclonal antibody (mAb) directed against rat hepatocytes was previously shown to inhibit adhesion of TA3/Ha mammary carcinoma cells to hepatocytes. The antigen is abundantly present at the surface of hepatocytes beneath the endothelium of liver capillaries where we have observed invasion of carcinoma cells to occur. The OPAR mAb reacted with three major bands on a Western blot of liver plasma membrane proteins. The same proteins were also seen upon immunoprecipitation from iodinated liver plasma membrane proteins. We have isolated OPAR antigens by lectin wheat germ agglutinin (WGA) and OPAR affinity chromatography. Amino acid sequence analysis revealed that two of the bands were 1-macroglobulin and C4-binding protein, which are serum components produced by hepatocytes. The presence of the epitope on distinct proteins and our previous observation that it can be detected in the Golgi apparatus but not in the endoplasmic reticulum, suggested that OPAR reacts with a liver-specific glycoconjugate. Loss of OPAR reactivity after neuraminidase and N-glycosidase F treatment showed that the epitope contains sialic acid residues on N-linked sugar moieties. OPAR also reacted with rat fibronectin, and inhibited adhesion of TA3/St cells to fibronectin. This explains the inhibition by the OPAR mAb of TA3/St cell adhesion to hepatocytes, which we have shown to be due mainly to interaction with hepatocyte surface-associated fibronectin. However, adhesion of the related TA3/Ha cells to hepatocytes, which is mediated by the 6P4 integrin, and does not involve binding to fibronectin, is also inhibited. This suggests that 64 on liver-metastasizing carcinoma cells binds to an OPAR epitope-carrying glycoprotein produced by hepatocytes.  相似文献   
63.
Due to the sharp increase in liver transplant candidates and the subsequent shortage of suitable donor livers, an extension of the current donor criteria is necessary. Simple cold storage, the current standard in organ preservation has proven to be insufficient to preserve extended criteria donor livers. Therefore a renewed interest grew toward alternative methods for liver preservation, such as hypothermic machine perfusion and normothermic machine perfusion. These “new” preservation methods were primarily assessed in rat models, and only a few clinically relevant large animal models have been described so far. This review will elaborate on these alternative preservation methods. Anat Rec, 291:735–740, 2008. © 2008 Wiley‐Liss, Inc.  相似文献   
64.
Previous studies have demonstrated the existence of nuclear carbohydrate binding proteins in a variety of mammalian cells with molecular masses of 35 000, 67 000, and 70 000 (CBP35, CBP67, and CBP70), which are associated with nuclear ribonucleoprotein (RNP) complexes. CBP35 consists of two domains, an aminoterminal portion that is homologous to certain regions of proteins of the heterogeneous nuclear RNP complex, and a carboxyl-terminal portion homologous to β-galactoside-specific lectins. CBP35 it has been proposed, like the glucose-specific lectin, CBP67, to guide RNP complexes through the nuclear pore. Here we show that the exposure of mature rats to stress induces an increase in nuclear CBP35 bound to CBP67 and retained on immobilized glucose. Nuclear extracts from the livers of old rats displayed no detectable stress response. This CBP35·CBP67 association detected in rat liver is considered with respect to the CBP35·CBP70 association recently observed in HL60 cell nuclear extracts.  相似文献   
65.
Institute of Therapy, Siberian Branch, Academy of Medical Sciences of the USSR, Novosibirsk. All-Union Preventive Medicine Research Center, Ministry of Health of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR Yu. P. Nikitin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 110, No. 12, pp. 611–613, December, 1990.  相似文献   
66.
67.
68.
分六个年龄组观察了180个(男98,女82)小儿肝的形态、度量、位置及体表投影.小儿肝相对较大,右叶大于左叶,下界位置较低并逐渐上移.在右锁骨中线的肋弓下一般均可触到.小儿肝重随其年龄(身高)的增长而增长,其增长速度相对较慢,尤以Ⅶ组小儿更明显.  相似文献   
69.
Hexokinase and glucokinase activity in the supernatant of a rabbit liver homogenate obtained at 18,000g was determined by a spectrophotometric method. Preliminary purification to remove low-molecular-weight components by gel filtration on Molselect G-50 dextran was shown to prevent reduction of NADP unconnected with the hexokinase reaction.Presented by Academician of the Academy of Medical Sciences of the USSR V. S. Il'in.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 7, pp. 891–892, July, 1976.  相似文献   
70.
采用聚合酶链反应(PCR)技术,对42例肝活切组织石蜡切片中乙型肝炎病毒(HBV)DNA进行检测,并与乙肝表面抗原(HBsAg)的免疫组织化学及血清学检测进行比较,HBV-PCR阳性率为73.8%,高于组织及血清HBsAg阳性率(分别为59.5%和50.0%)。3例病理形态呈肝炎改变,而血清HBsAg(─)的肝组织中有2例检出HBV-DNA,提示PCR的高度敏感性和准确性。83.3%的门脉性肝硬变和87.5%的肝细胞癌组织中HBV-PCR呈阳性,进一步证实了上述两病与HBV的关系密切。我们还发现肝细胞淤胆患者HBV感染率较高,HBV-DNA及组织HBsAg阳性比例各为6/9和4/8。  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