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   262篇
  免费   19篇
  国内免费   2篇
耳鼻咽喉   2篇
儿科学   6篇
妇产科学   2篇
基础医学   102篇
口腔科学   5篇
临床医学   3篇
内科学   21篇
皮肤病学   12篇
神经病学   57篇
特种医学   1篇
外科学   18篇
综合类   10篇
预防医学   3篇
眼科学   5篇
药学   2篇
肿瘤学   34篇
  2023年   2篇
  2022年   3篇
  2021年   2篇
  2020年   4篇
  2019年   4篇
  2018年   3篇
  2017年   7篇
  2016年   6篇
  2015年   6篇
  2014年   8篇
  2013年   11篇
  2012年   6篇
  2011年   9篇
  2010年   7篇
  2009年   11篇
  2008年   16篇
  2007年   15篇
  2006年   7篇
  2005年   10篇
  2004年   8篇
  2003年   13篇
  2002年   10篇
  2001年   12篇
  2000年   8篇
  1999年   8篇
  1998年   11篇
  1997年   13篇
  1996年   10篇
  1995年   11篇
  1994年   5篇
  1993年   5篇
  1992年   6篇
  1991年   5篇
  1990年   5篇
  1989年   1篇
  1988年   7篇
  1987年   2篇
  1986年   1篇
  1984年   3篇
  1983年   1篇
  1982年   1篇
排序方式: 共有283条查询结果,搜索用时 31 毫秒
1.
T-cell infiltration was detected by immunohistochemistry in only 2 of 10 sural nerve biopsies from patients with Guillain-Barré syndrome (GBS). The number of endoneurial macrophages, identified by the monoclonal antibody MAC 387, was increased, compared with the number in 10 cases of axonal neuropathy. Macrophage-associated demyelination was identified in 7 and axonal degeneration in 8 cases. Cytomegalovirus (CMV) genome was not detected with the polymerase chain reaction.  相似文献   
2.
To evaluate the clinical applicability of galectin-3 and CD44 variant 6 (CD44v6) immunostaining in fine-needle aspiration cytology (FNAC) of thyroid follicular tumors, 79 cytological specimens (35 follicular carcinomas and 44 follicular adenomas) were studied. The positive rates of galectin-3 and CD44v6 were 89 and 74% in follicular carcinoma, respectively, and 25 and 30% in follicular adenoma, respectively. There were no significant correlations between the expression of galectin-3 or CD44v6 in follicular carcinoma and characteristics such as capsular invasion, vascular invasion, metastasis, or tumor size. Positive staining of either galectin-3 or CD44v6 resulted in a diagnostic sensitivity of 97% and a specificity of 52% for follicular carcinoma among follicular tumors. Immunostaining of galectin-3 or CD44v6 using cytological specimens can provide independent information on conventional morphological findings of cytology to distinguish follicular carcinoma from adenoma.  相似文献   
3.
4.
This study presents a comparative analysis of gangliosides from lymphoid (spleen and thymus) and other (brain, liver, lungs and muscle) tissues of C57BL/6 mice lacking the gene for beta2-microglobulin (beta2M), a constitutive component of the MHC class I molecule. Ganglioside fractions in the tissues of mice homozygous (beta2M-/-) and heterozygous (beta2M-/+) for the gene deletion were determined by high performance thin-layer chromatography (HPTLC), followed by immunostaining with specific polyclonal antibodies. Ubiquitous gangliosides GM3(Neu5Ac) and GM3(Neu5Gc) were the dominant gangliosides in the lungs of the control beta2M-/+ mice, whereas the homozygous knockout mice had substantially decreased expression of these structures. The lungs of the beta2M-/- mice also had reduced expression of T-lymphocyte-specific GM1b-type gangliosides (GM1b and GalNAc-GM1b). beta2M-deficient mice also had more GM1a and GD1a gangliosides in the liver, and several neolacto-series gangliosides were increased in the brain and lungs. This study provides in vivo evidence that the beta2M molecule can influence the acquisition of a distinct ganglioside assembly in different mouse organs, implicating its non-immunological functions.  相似文献   
5.
Summary The relationship between tumor proliferative activity and response to first-line chemotherapy and survival was investigated in 76 advanced breast cancer patients. Proliferative activity was determined by means of Ki-67 immunohistologic staining on primary tumors (55 patients) or at the relapse site (21 patients), and was classified as low ( 25% of stained cells) or high (> 25% of stained cells). The usual WHO response criteria were used. The median duration of follow-up was 18 months (range 3–58).Forty-seven patients (62%) had tumors with low, and 29 (38%) had tumors with a high rate of proliferative activity. The two groups were well balanced in terms of important variables such as disease-free survival, performance status, age, menopausal status, and the type of first-line chemotherapy (anthracycline-based regimens versus cyclophosphamide-methotrexate-5-fluorouracil). The estrogen receptor (ER) content, measured by means of immunohistochemical assay, was markedly different in the two groups, with 27/47 tumors with low proliferative activity (57%) and 6/29 with high-proliferative activity (21%) being ER positive ( 45% of stained cells) (p = 0.003). Moreover, a significant difference in the metastatic pattern was also evident, with a higher incidence of bone and a lower incidence of soft tissue metastases in the group of patients with tumors with low proliferative activity (p = 0.004). Overall, 10/47 responses (21%: PR = 7, and CR = 3) were observed in the group with a low rate of proliferative activity, versus 14/29 (48%: PR = 9, and CR = 5) in the group with highly proliferative tumors, the difference being statistically significant (p = 0.03). When a multivariate analy-sis was performed, the only factor that retained independent prognostic significance was the predominant site of disease, particularly soft tissues (p = 0.003). Despite the difference in response rate, when survival analysis was performed according to the Kaplan-Meier method, no significant difference was observed in the two groups, but when the analysis was limited to responsive patients, the median survival observed in those with a low and those with a high rate of proliferation was 35 and 19 months respectively (p = 0.02). The same results were obtained when multivariate survival analysis was carried out using Cox's regression model. These data suggest that there is a link between tumor proliferative activity and response to chemotherapy in advanced breast cancer, and may indicate the need to use more intensive treatments in selected patients with highly proliferative tumors.Presented in part at the Annual Meeting of the American Society of Clinical Oncology, May 14–17, 1994, Dallas, TX, USA  相似文献   
6.
Experimental laboratory data suggest that tumour growth is a balance between apoptosis and proliferation and that suppression of drug-induced apoptosis by oncogenes such as bcl-2 may be an important cause of intrinsic chemoresistance. The aims of this study were to assess the in vivo relationship of apoptosis to proliferation and Bcl-2 protein in human breast tumours both prior to chemotherapy and in the residual resistant cell population at the completion of treatment. We examined apoptotic index (AI), Ki67 and Bcl-2 protein expression in the tissue of 40 patients with operable breast cancer immediately before ECF preoperative chemotherapy, and in 20 of these patients with residual tumour, at the completion of treatment. There was a significant positive association between AI and Ki67 both before and after chemotherapy, and in their percentage change with treatment. In the residual specimens AI and Ki67 were significantly reduced compared with pre-treatment biopsies, while Bcl-2 expression showed a significant increase. No differences were seen in the pre-treatment levels of any of the variables measured between patients obtaining pathological complete response and those who did not, although numbers were small. These data suggest that apoptosis and proliferation are closely related in vivo. It is possible that the phenotype of reduced apoptosis and proliferation, and increased Bcl-2 may be associated with breast cancer cells resistant to cytotoxic chemotherapy, although this can only be proven by assessing larger numbers of patients in relation to pathological response.  相似文献   
7.
Fatty infiltration is associated with an increased incidence of complications and mortality after liver resection and transplantation. The aim of this study was to document the regenerative response in patients with hepatic steatosis and mild inflammatory activity (NASH) and to identify potential levels of impaired regeneration. Ki-67 immunostaining was similar in patients with NASH (ages 44.6 ± 15 years, labeling index, 0.4 ± 0.3%) when compared to patients with chronic hepatitis C infection (ages 50.7 ± 17 years, labeling index; 0.4 ± 0.7%). The labeling index was not increased in patients with a higher level of inflammation, a higher level of fibrosis, and a higher level of fat in either study group. In conclusion, liver regeneration is not altered in patients with nonalcoholic steatohepatitis, suggesting that the delayed postoperative liver failure seen in these patients may be related to another mechanism.  相似文献   
8.
The present study investigates whether lymphatic vessel invasion (LVI) detected by D2‐40 staining is a prognostic factor for stage I adenocarcinoma of the lung. We retrospectively reviewed 124 patients who underwent complete resection for stage I adenocarcinoma of the lung from January 1983 to June 2003. LVI was microscopically evaluated using D2‐40 immunostaining. The median follow‐up was 71 months. The LVI positive rate was 37%. The 5‐year cancer‐specific survival rates of the D2‐40 positive LVI and negative groups were 88.8% and 84.3%, respectively (P = 0.630). The stage I lung adenocarcinoma patients who were determined to be LVI positive based on D2‐40 immunostaining did not have a significantly poorer prognosis than the LVI negative cases. Thus, lymphatic microinvasion may not be a prognostic indicator in early lung cancer, although advanced LVI does appear to correlate with survival. It is therefore unnecessary to use D2‐40 immunostaining to diagnose LVI in practical settings, and Hematoxylin‐Eosin and Elastica van Gieson staining should continue to be used to predict the prognosis of patients with stage I lung adenocarcinoma.  相似文献   
9.
Membrane-type 1 matrix metalloproteinase (MT1-MMP, also known as MMP14), the best characterized membrane-anchored MMP, is an important matrix-degrading proteinase that could digest a broad spectrum of extracellular matrix proteins and accelerate angiogenesis. We have previously reported that some MMPs involved in the angiogenesis and the pannus formation within the joint, leading to the erosion of articular cartilage and bone in the pathological process of rheumatoid arthritis (RA). In the present study, we used immunohistochemistry assay and con-focal scanning technique to study the detailed immunolocalization of MT1-MMP in human RA synovium tissues as well as the infiltrating immune cell subsets. Our results showed that the positive MT1-MMP immunostaining could be found in synoviocytes, vascular endothelial cells, infiltrating macrophages and monocytes in RA synovium tissues, while weak or negative immunostaining could be found in infiltrating T cells, B cells and NK cells, respectively. Moreover, the Ki-67+ highly proliferating synoviocytes also showed higher MT1-MMP expression in RA synoviocytes. Thus, the aberrant expression of MT1-MMP in RA synoviocytes as well as infiltrating immune cells may contribute to the proliferation of the synoviocytes, and the angiogenesis and the pannus formation in RA pathological progression.  相似文献   
10.
We report the case of a baby with low birthweight born by emergency caesarean section at 33 weeks 2 days' gestation due to placental abruption. High‐mobility group box‐1 (HMGB‐1) and interleukin‐17 concentration in the umbilical cord blood were high at 55.7 ng/mL and 50.7 pg/mL, respectively. On immunostaining of umbilical cord and amniotic epithelium, HMGB‐1 was identified in the nuclei of vascular endothelial cells and cytoplasm of the surrounding cells in the umbilical cord. This suggests that, in the present case of placental abruption and subsequent ischemic placenta and fetus, the high level of HMGB‐1 observed was due to the release of HMGB‐1 into the umbilical cord blood from the vascular endothelial cells of the umbilical cord.  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