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   27253篇
  免费   1182篇
  国内免费   170篇
耳鼻咽喉   240篇
儿科学   518篇
妇产科学   459篇
基础医学   3544篇
口腔科学   446篇
临床医学   1586篇
内科学   6785篇
皮肤病学   367篇
神经病学   2460篇
特种医学   1064篇
外科学   4571篇
综合类   100篇
一般理论   5篇
预防医学   767篇
眼科学   609篇
药学   1657篇
中国医学   68篇
肿瘤学   3359篇
  2023年   116篇
  2022年   264篇
  2021年   448篇
  2020年   241篇
  2019年   339篇
  2018年   438篇
  2017年   386篇
  2016年   435篇
  2015年   469篇
  2014年   604篇
  2013年   749篇
  2012年   1254篇
  2011年   1352篇
  2010年   800篇
  2009年   678篇
  2008年   1200篇
  2007年   1356篇
  2006年   1330篇
  2005年   1312篇
  2004年   1246篇
  2003年   1295篇
  2002年   1419篇
  2001年   740篇
  2000年   793篇
  1999年   756篇
  1998年   393篇
  1997年   306篇
  1996年   294篇
  1995年   271篇
  1994年   273篇
  1993年   274篇
  1992年   681篇
  1991年   609篇
  1990年   574篇
  1989年   580篇
  1988年   530篇
  1987年   524篇
  1986年   455篇
  1985年   455篇
  1984年   262篇
  1983年   222篇
  1982年   101篇
  1979年   237篇
  1978年   129篇
  1977年   109篇
  1975年   108篇
  1974年   102篇
  1973年   104篇
  1970年   104篇
  1969年   117篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
Humoral hypercalcemia of malignancy (HHM) in neoplastic syndrome has been most commonly reported in squamous cell carcinoma. Gallbladder carcinoma with HHM is uncommon. In this report, we describe a male case of gallbladder carcinoma with marked hypercalcemia and a high level of serum parathyroid hormone-related peptide (PTHrP). An immunohistochemical examination using PTHrP was also positive.  相似文献   
14.
15.
16.
Ketogenic capacity of mitochondria from the remnant liver of 70% hepatectomized rats was studied in relation to mitochondrial phosphorylative activity. Ketogenic capacity increased to a maximum of 6.04 +/- 0.39 from 3.84 +/- 0.13 of control, with an enhancement of mitochondrial phosphorylative activity 6 hr after hepatectomy, and then decreased to normal levels within 24 hr. Adenylate energy charge, (ATP + 1/2ADP)/(ATP + ADP + AMP), of the remnant liver decreased to 0.825 +/- 0.006 as compared to 0.849 +/- 0.002 of control 6 hr after operation. At 12 hr, total ketone body concentrations of the arterial blood increased concomitant with a fall in ketone body ratio (acetoacetate/3-hydroxybutyrate) which reflects the decreased liver mitochondrial redox (NAD+/NADH) state. These findings suggest that an enhancement of mitochondrial fatty acid oxidation and ketogenesis occurs concomitant with an enhancement of mitochondrial phosphorylative activity in the remnant liver in response to a decreased energy charge after 70% hepatectomy.  相似文献   
17.
Using high resolution ultrasonography (US), diagnostic accuracy of thrombi in each venous segment of lower limbs and qualitative evaluation of thrombi in deep vein thrombosis (DVT) were investigated. The subjects were 106 lower limbs in 81 patients. The thrombi in common femoral vein (CFV), were diagnosed by compression technique and, were qualitatively analysed by echogenicity and consistency. Venography was performed in 18 limbs and histologic tests of thrombi were made in 6 limbs. The total accuracy of US was 100% for diagnosis of DVT, but was 83% for diagnosis of its extent. The total accuracy of US in each segment was greater than 90%, but the sensitivity of iliac veins was less than 90%. The thrombi in CFV were divided into 3 types and 8 sub-types. Type A was homogenous, type B was heterogenous, and type C was contracted echo. The types of us were consistent with results of histologic tests. We concluded that high resolution US is available for screening test for diagnosis of DVT and that qualitative evaluation of thrombi by US is a useful clinical test for selection of more adequate treatments.  相似文献   
18.
The tumor vessels of a primary meningeal malignant melanoma were studied by electron microscopy. There were numerous endothelial fenestrae and basal lamina abnormalities in the intrinsic tumor capillaries. They resembled the tumor vessels found in nonglial tumors, but were distinctly different from those seen in glial tumors with nonfenestrated capillaries. These findings were anticipated because leptomeninges have fenestrated capillaries.  相似文献   
19.
20.
Immunopathogenicity of trypsin-solubilized or non-solubilized renal tubular basement membrane (TBM) of the Lewis (LEW) rat was investigated. Autoimmune tubulointerstitial nephritis (TIN) was induced in BALB/c mice by immunization with trypsin-solubilized LEW rat TBM, while immunization with non-solubilized TBM did not produce the disease. Based on this preliminary experiment we studied the characterization of immunogenic and nephritogenic TBM antigen of the LEW rat. TIN was characterized by severe mononuclear cell infiltrates with multi-nucleated giant cells in the interstitium, tubular destruction and intensive IgG and C3 deposits along the TBM. Anti-TBM antisera and eluate from the nephritic mouse kidneys reacted with the TBM of normal LEW rat kidney by immunofluorescence. LEW rat TBM was also detected immunofluorescently by using antisera from BALB/c mice immunized with autologous trypsin-solubilized TBM. A competitive inhibition test revealed a higher titer of anti-TBM antibody in the eluate than in the adsorption-treated antisera per microgram IgG. Immunoblotting showed one reactive band with a molecular weight of 45,000 daltons, and the blotting patterns in tryptic TBM of the Brown Norway (BN) and LEW rats appeared similar. Amino acid analysis of nephritogenic LEW rat tryptic TBM showed that it contained no hydroxyproline and hydroxylysine, suggesting that this TBM preparation was not collagenous. These findings suggest that tryptic digestion contributes to the release of nephritogenic antigen from the LEW rat TBM and that this antigen system might participate in the immune system involved in the anti-TBM associated TIN that is well known to be induced by non-digested TBM of TBM antigen positive animals.  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