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   270篇
  免费   10篇
  国内免费   2篇
儿科学   1篇
基础医学   20篇
口腔科学   6篇
临床医学   11篇
内科学   73篇
皮肤病学   18篇
神经病学   6篇
特种医学   3篇
外科学   74篇
综合类   1篇
预防医学   5篇
眼科学   1篇
药学   4篇
肿瘤学   59篇
  2023年   1篇
  2022年   4篇
  2021年   13篇
  2020年   6篇
  2019年   7篇
  2018年   5篇
  2017年   3篇
  2016年   9篇
  2015年   9篇
  2014年   5篇
  2013年   8篇
  2012年   20篇
  2011年   23篇
  2010年   14篇
  2009年   7篇
  2008年   7篇
  2007年   11篇
  2006年   12篇
  2005年   15篇
  2004年   11篇
  2003年   22篇
  2002年   10篇
  2001年   11篇
  2000年   9篇
  1999年   4篇
  1998年   2篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   3篇
  1991年   1篇
  1989年   3篇
  1987年   5篇
  1985年   2篇
  1984年   2篇
  1983年   4篇
  1979年   2篇
  1978年   4篇
  1974年   2篇
  1969年   1篇
  1967年   2篇
排序方式: 共有282条查询结果,搜索用时 15 毫秒
61.
Some patients with nongonococcal urethritis (NGU) are negative for Chlamydia trachomatis, mycoplasmas, and ureaplasmas. The optimal antimicrobial chemotherapy for such NGU has not fully been clarified. We assessed the efficacy of azithromycin for treatment of nonmycoplasmal, nonureaplasmal, nonchlamydial NGU (NMNUNCNGU). Thirty‐eight men whose first‐pass urine was negative for Chlamydia trachomatis, Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum, and Ureaplasma urealyticum were treated with a single dose of 1 g azithromycin. Urethritis symptoms and polymorphonuclear leukocytes in urethral smears or in first‐pass urine were assessed before and after treatment with azithromycin. Thirty‐two (84.2%) of the 38 men with NMNUNCNGU showed no signs of urethral inflammation after treatment. The efficacy of this azithromycin regimen was comparable to that of the 7‐day regimen of levofloxacin, gatifloxacin, minocycline, or clarithromycin reported previously. A single dose of 1 g azithromycin, which is effective not only for NGU due to specific pathogens but also for NMNUNCNGU, is an appropriate treatment for NGU.  相似文献   
62.
63.
Noriko Sho  md    Arata Oiji  md  phd  Chizue Konno  ma    Koji Toyohara  md    Tatsuya Minami  md  phd  Takashi Arai  md  phd  Yoji Seike  md  phd 《Psychiatry and clinical neurosciences》2009,63(3):410-416
Aims:  The objectives of the present study were to (i) evaluate the prevalence of children and adolescents who have engaged in intentional self-harm using a sharp object; and (ii) investigate the relationship between self-harm with sharp objects and depressive tendencies or dissociative tendencies.
Methods:  A total of 1938 students in grades 5–12 in Yokohama, Japan, were enrolled, and they completed anonymous self-report questionnaires including a question about intentional self-harm with a sharp object, the Depression Self-Rating Scale for Children (DSRSC) and the Adolescent Dissociative Experiences Scale (A-DES).
Results:  The prevalence of self-harm using sharp object was 5.4% among male 5th–6th graders, 4.0% among female 5th–6th graders, 5.3% among male 7th–9th graders, 15.1% among female 7th–9th graders, 6.6% among male 10th–12th graders, and 9.6% among female 10th–12th graders. Categorical regression analysis showed that a small amount of variance in self-harm by sharp object was explained by DSRSC and A-DES scores.
Conclusions:  Self-harm with a sharp object was prevalent among pre-adolescents and adolescents and was associated with depressive and dissociative tendencies.  相似文献   
64.
Epithelial to mesenchymal transition (EMT) is induced by transforming growth factor-β1 (TGF-β1) and is a crucial event for cancer cells to acquire invasive and metastatic phenotypes. However, the signals that induce EMT in cancer cells have yet to be adequately defined. In this study, a proteomic investigation was performed to understand the signaling pathway of the EMT of lung cancer using two-dimensional difference gel electrophoresis (2D-DIGE) and mass spectrometry. The protein expression profiles of A549 were compared to those of A549 cells treated with TGF-β1. Of more than 2,000 protein spots shown by 2D-DIGE, 53 were found to be up- or down-regulated upon induction with TGF-β1. In the 53 protein spots, the protein level of heat shock protein (HSP) 27 was found to increase significantly. HSP27 protein was higher in two different lung cancer cell lines, demonstrating the EMT phenomenon with TGF-β1. Notably, the silencing of HSP27 enhanced spindle integration, resulting in an additive effect with TGF-β1-induced EMT. Furthermore, the TGF-β1-induced HSP27 increase was not affected by the suppression of Smad2 and Smad3 in A549 cells. These results suggest that HSP27 was involved in TGF-β1-induced EMT in a Smad-independent manner in lung cancer cells and may provide an effective clinical strategy in lung cancer patients whose tumors are dependent on TGF-β1-induced EMT.  相似文献   
65.
The mannose 6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2R) is involved in activating the transforming growth factor beta(1) (TGF-beta(1)), an inhibitor of the cell proliferation, and limiting the insulin-like growth factor 2 mediated-growth stimulation. The M6P/IGF2R gene has been reported to be mutated and deleted in various cancers, and is a candidate tumor suppressor gene. We studied the genomic structure of the M6P/IGF2R gene and designed the intron primers to detect mutations in the M6P/IGF2R gene of genomic DNA samples. The M6P/IGF2R gene consists of 48 exons. The previously reported 23 mutations of the M6P/IGF2R gene in human cancers, liver, breast, and gastrointestinal tumors, are located in five exons, exon 27, 28, 31, 40, 48. Using the intron primers designed in this study, polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis, and direct sequencing, we performed an initial analysis of the complete coding sequences of the M6P/IGF2R gene in 21 human cell lines resistant to growth inhibition by TGF-beta(1). An adenine-to-guanine transition, resulting in an asparagine-to-serine amino acid substitution, was found in one lung adenocarcinoma cell line at exon 40 where the mutation has been previously reported in human cancers. This is the first report of a mutation of the M6P/IGF2R gene in lung tumor. These results indicated that the mutation in M6P/IGF2R may be involved in human lung cancinogenesis.  相似文献   
66.
Nitropyrenes are widespread in the environment due to mainly diesel engine emissions. Dinitropyrenes (DNPs), especially 1,8-dinitropyrene (1,8-DNP) and 1,6-dinitropyrene (1,6-DNP), are much more potent mutagens than other nitropyrenes. The carcinogenicity of 1,8-DNP and 1,6-DNP is stronger than 1,3-dinitropyrene (1,3-DNP). It is considered that adduct formation after metabolic activation plays an important role in the expression of carcinogenicity of nitropyrenes. However, Djuric et al. [(1993) Cancer Lett.] reported that oxidative DNA damage was also found as well as adduct formation in rats treated with 1,6-DNP. We investigated oxidative DNA damage by DNPs in the presence of NAD(P)H-cytochrome P450 reductase using 32P-5'-end-labeled DNA. After P450 reductase treatment, DNPs induced Cu(II)-mediated DNA damage in the presence of NAD(P)H. The intensity of DNA damage by 1,8-DNP or 1,6-DNP was stronger than 1,3-DNP. We also examined synthetic 1-nitro-8-nitrosopyrene (1,8-NNOP) and 1-nitro-6-nitrosopyrene (1,6-NNOP) as one of the metabolites of 1,8-DNP and 1,6-DNP, respectively, to find that 1,8-NNOP and 1,6-NNOP induced Cu(II)-mediated DNA damage in the presence of NAD(P)H but untreated DNPs did not. In both cases of P450 reductase-treated DNPs and NNOPs, catalase and a Cu(I) specific chelator attenuated DNA damage, indicating the involvement of H2O2 and Cu(I). Using a Clarke oxygen electrode, oxygen consumption by the reaction of NNOPs with NAD(P)H and Cu(II) was measured to find that NNOP was nonenzymatically reduced by NAD(P)H and that the addition of Cu(II) promoted the redox cycle. Therefore, these results suggest that DNPs are enzymatically reduced to NNOPs via nitro radical anion and that NNOPs are further reduced nonenzymatically by NAD(P)H. Subsequently, autoxidation of nitro radical anion and the reduced form of NNOP occurs, resulting in O2- generation and DNA damage. We conclude that oxidative DNA damage in addition to DNA adduct formation may play important roles in the carcinogenesis of DNPs via their metabolites.  相似文献   
67.
Aberrant accumulation of beta-catenin protein because of mutation of either the beta-catenin or adenomatous polyposis coli gene plays an essential role in the development of colorectal carcinoma. We established previously a stable clone of the rat small intestinal epithelial cell line IEC6, which is capable of inducing stabilized beta-catenin protein lacking NH(2)-terminal glycogen synthase kinase-3beta phosphorylation site under a strict control of the tetracycline-regulatory system. This clone, IEC6-TetOFF-beta-catenin DeltaN89, shows in vitro polypoid growth on the removal of doxycycline and seems to be an appropriate model for analyzing the molecular mechanisms of early intestinal carcinogenesis. Of >2000 protein spots displayed by newly developed two-dimensional difference gel electrophoresis, 22 were found to be up- or down-regulated on the induction of stabilized beta-catenin. The majority of these proteins fell into two categories: (a) redox-status regulatory proteins and (b) cytoskeleton-associated proteins. Representatively, a key redox-status regulatory protein, manganese superoxide dismutase, up-regulated in IEC6 cells expressing stabilized beta-catenin protein, was overexpressed in adenoma and adenocarcinoma cells of familial adenomatous polyposis patients in parallel with the accumulation of beta-catenin. These results suggest that aberrant accumulation of beta-catenin might contribute to colorectal carcinogenesis by affecting redox status in the mitochondria of intestinal epithelial cells.  相似文献   
68.
Summary Intraluminal crystalloids (ICr) observed in 19 cases of incidental or invasive human prostatic carcinoma (PCa) and in a case of benign prostatic hyperplasia were examined extensively by immunohistochemistry and electron microscopy. They were brilliantly eosinophilic with haematoxylin and eosin, manifesting needlelike, triangular, rectangular, hexagonal and irregular lump-like in shape. They were strongly positive, dark blue, with phosphotungstic acid -haematoxylin (PTAH) stain in all cases examined. Among the human antibodies tested, epithelial membrane antigen (EMA) gave specifically positive immunostainability with ICr in all cases. Annual ring-like lamellar or concentric structures were detected by electron microscopy. Positive staining of ICr with PTAH and anti-EMA antibody is very useful as a diagnostic marker for PCa in human prostatic tissues.  相似文献   
69.
Background. Epstein-Barr virus (EBV), the etiological agent of infectious mononucleosis, has an important role in the oncogenesis of EBV-related malignant diseases. The association of EBV with gastric carcinoma cells has become well known recently, but there are only a few reports concerning its association with surrounding epithelia and infiltrating lymphocytes. In this study, we investigated the association of EBV with gastric carcinoma and surrounding cells. Methods. One hundred and two cases of gastric carcinoma were studied. The specimens were studied for the presence of the EBV genome by polymerase chain reaction (PCR), and then by in situ hybridization (ISH) technique to determine the localization of EBV. Results. Of 97 informative cases, EBV was detected in 21 cases (21.6%) by the PCR method. ISH studies showed that EBV RNA was expressed in 5 of the 97 cases (5.2%) and was localized to the nuclei of carcinoma cells. All these 5 lesions were found in male patients. In these 5 cases, 3 were diffuse type and 2 were intestinal type, and all cases arose in the proximal region of the stomach. EBV RNA was not detected in non-neoplastic epithelia, but it was detected in 24 of the 97 cases (24.7%) in small lymphocytes. Conclusion. EBV was detected in 5.2% of gastric carcinomas and in 24.7% of infiltrating lymphocytes by the ISH method. The high positive rate (21.6%) by the PCR method corresponds to the presence of the EBV genome in surrounding lymphocytes.  相似文献   
70.
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