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   771篇
  免费   70篇
  国内免费   10篇
耳鼻咽喉   9篇
儿科学   7篇
妇产科学   50篇
基础医学   84篇
口腔科学   7篇
临床医学   70篇
内科学   299篇
皮肤病学   18篇
神经病学   47篇
特种医学   20篇
外科学   74篇
综合类   7篇
预防医学   33篇
眼科学   9篇
药学   33篇
中国医学   2篇
肿瘤学   82篇
  2023年   12篇
  2022年   18篇
  2021年   32篇
  2020年   14篇
  2019年   21篇
  2018年   21篇
  2017年   28篇
  2016年   35篇
  2015年   32篇
  2014年   45篇
  2013年   59篇
  2012年   62篇
  2011年   55篇
  2010年   47篇
  2009年   34篇
  2008年   54篇
  2007年   69篇
  2006年   49篇
  2005年   38篇
  2004年   28篇
  2003年   28篇
  2002年   25篇
  2001年   6篇
  2000年   3篇
  1999年   3篇
  1998年   5篇
  1997年   5篇
  1996年   1篇
  1995年   4篇
  1994年   2篇
  1993年   1篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1980年   1篇
  1979年   1篇
  1978年   2篇
  1975年   1篇
  1973年   2篇
  1931年   1篇
  1930年   1篇
排序方式: 共有851条查询结果,搜索用时 15 毫秒
11.
12.
13.
ABSTRACT: BACKGROUND: The leaves of Leea indica (Vitaceae), commonly known as 'Huo Tong Shu' in Malaysia, have been traditionally used as natural remedy in folk medicine by the locals. The current study reports the outcome of antioxidant and cytotoxic investigation of L. indica leaves. To the best of our knowledge, this is the first report of L. indica leaf crude ethanol and its fractionated extracts (hexane, ethyl acetate and water) for evaluation of total phenolic content, antioxidant effect and cytotoxic activity against colon cancer cell lines. METHODS: In the present study, L. indica leaf crude ethanol and its fractionated extracts (hexane, ethyl acetate and water) were firstly prepared prior to phenolic content, antioxidant effect and cytotoxic activity assessment. Folin-Ciocalteau's method was used for the measurement of total phenolic content of the extracts. The antioxidant activity was measured by employing three different established testing systems, such as scavenging activity on DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals, reducing power assay and SOD (superoxide dismutase) activity assay. The cytotoxic activity of the extracts were evaluated against three colon cancer cell lines with varying molecular characteristics (HT-29, HCT-15 and HCT-116) by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. RESULTS: The total phenolic content and antioxidant capabilities differed significantly among the L. indica leaf extracts. A strong correlation between total phenolic content and antioxidant properties was found, indicating that phenolic compounds are the major contributor to the antioxidant properties of these extracts. Among the crude ethanol and its fractionated extracts, fractionated water extract showed significantly the highest total phenolic content and strongest antioxidant effect in all the antioxidant testing systems employed in this study. All the four extracts exert no damage to the selected colon cancer cells. CONCLUSIONS: The data obtained in these testing systems clearly establish the antioxidant potency of the fractionated water extract of L. indica leaves. Additional studies should be carried out to isolate and identify the bioactive compounds in the fractionated water extract, in order to provide more convincing evidence.  相似文献   
14.
Ionized calcium binding adaptor molecule 1 (Iba1) is associated with membrane ruffling and motility of cells. Galectin-3 (Gal-3) is a β-galactoside binding animal lectin, and regulates fibrogenesis probably through transforming growth factor-β1. To evaluate macrophage properties, expressions of Iba1 and Gal-3 were investigated, in relation to macrophages expressing CD68 (ED1; reflecting increased phagocytosis) and CD163 (ED2; implying proinflammatory factor productions) in centrilobular lesions induced in rat livers with thioacetamide (TAA; 300 mg/kg body weight, once intraperitoneally). In agreement with expression patterns of CD68+ and CD163+ macrophages, cells reacting to Iba1 and Gal-3 were increased in numbers on post-injection (PI) days 1–5, peaking on day 2; thereafter, the positive cells gradually decreased to control levels until PI days 7 and 10. The increased expressions of Iba1 and Gal-3 were confirmed at mRNA levels by the RT-PCR. Double immunofluorescence staining on PI days 2 and 3 demonstrated Iba1 expression in 15–46% of CD68+ and CD163+ macrophages, and Gal-3 expression in 65–82% of CD68+ and CD163+ macrophages; Gal-3 expression was observed in 84–93% of Iba1+ cells. Interestingly, Gal-3 was also expressed in a small number of α-smooth muscle actin-positive myofibroblasts in fibrotic lesions developed in injured centrilobular areas. These findings indicate that macrophages with various functions can participate in development of liver lesions and resultant fibrosis. Besides CD68 and CD163, Iba1 and Gal-3 immunohistochemistry for macrophages would be useful to analyze the pathogenesis behind developing hepatotoxicity.  相似文献   
15.
We report a rare case of large-cell neuroendocrine carcinoma of the breast. A 63-year-old woman was admitted to our hospital with a firm mass in the right breast. Mammography revealed a high-density mass with specula, and ultrasonography showed a heterogeneous hypoechoic mass with irregular margin and posterior acoustical shadowing. She underwent breast-conserving surgery with axillary lymph node dissection. Histopathologically, the tumor consisted of large cells with polygonal and prominent nuclei and a small amount of eosinophilic cytoplasm, and these cells showed palisading arrangement with fibrous stroma. The tumor cells were positive for neuroendocrine markers such as NSE, synaptophysin, CD56 (NCAM), but not for chromogranin A. Interestingly, the tumor cells showed reactivity for cytokeratin 20 but not for cytokeratin 7. The immunostaining pattern is different from the usual adenocarcinoma of the breast. The patient received postoperative radiotherapy and was given adjuvant chemotherapy. She has remained disease-free for 44?months.  相似文献   
16.
17.
18.
A radioimmunoassay method of motilin was developed in our laboratory and was validated in dogs with a platinum monopolar electrode in the duodenum. We confirmed that a bolus infusion of 0.3 M tris-buffer solution or 0.1 N HCl solution in the duodenum produces a significant rise in plasma immunoreactive motilin (IRM) concentrations. This coincided with a marked increase in the percentage of spike potentials on slow waves of the duodenum, similar to phase III of interdigestive myoelectric-activity (MA). A possible relationship between plasma IRM and interdigestive MA of canine duodenum was studied. It was found that cyclic changes occurred in the fasting plasma IRM concentrations in dogs. While the peak motilin concentration was always observed in phase III, the lowest concentration of motilin was found in phase I of interdigestive MA in the duodenum. In dogs with the electrodes in the duodenum and jejunum, the peak IRM concentration did not correlate with phase III of interdigestive MA in the jejunum. A dose of synthetic porcine motilin, 0.06 g/kg/hr, which produced the plasma IRM concentration comparable to the peak fasting motilin concentration, could induce an identical phase III in the duodenum. These observations indicate that there is a relationship between cyclic changes in plasma IRM concentrations and interdigestive MA of the duodenum. It is suggested further that motilin is a hormone which may play an important role in inducing phase III of interdigestive MA in the duodenum.This work was supported by the Gastrointestinal Research Fund at The Genesee Hospital.  相似文献   
19.
Gastric tuberculosis presenting as a submucosal tumor   总被引:1,自引:0,他引:1  
  相似文献   
20.
Well‐differentiated papillary mesothelioma (WDPM) is a distinct subtype of mesothelial tumor from diffuse malignant mesothelioma (DMM), with an uncertain malignant potential. The relationship between WDPM and DMM, with regard to the ability of the former to develop into the latter, is also unknown. A 58‐year‐old woman, diagnosed with a rectal carcinoid tumor, underwent removal of the lymph nodes via the abdomen in 2004. A large number of white miliary nodules were identified on the mesentery and peritoneum, which were histologically diagnosed as WDPM. No further therapy was administered, but the patient was followed‐up using imaging methods. Seven years later, an abdominal wall mass was discovered using positron emission tomography‐computed tomography, and a laparotomy biopsy was performed. DMM was diagnosed, because mesothelioma with extended invasion had been histologically identified. Mesothelioma similar to papillary proliferation was present on the outer layer of the peritoneum, and an infiltrating lesion with continuous restiform or solid‐like structures was noted. WDPM was believed to have undergone malignant transformation. Compared to DMM, WDPM has a good prognosis and is considered a benign or borderline neoplasm. Our findings suggest that WDPM does have malignant potential, however, because histological findings indicated a malignant transformation of WDPM to DMM.  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