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   3197篇
  免费   153篇
  国内免费   17篇
耳鼻咽喉   78篇
儿科学   30篇
妇产科学   28篇
基础医学   415篇
口腔科学   47篇
临床医学   185篇
内科学   898篇
皮肤病学   39篇
神经病学   223篇
特种医学   84篇
外科学   517篇
综合类   10篇
预防医学   118篇
眼科学   27篇
药学   156篇
中国医学   2篇
肿瘤学   510篇
  2023年   18篇
  2022年   36篇
  2021年   67篇
  2020年   42篇
  2019年   27篇
  2018年   47篇
  2017年   40篇
  2016年   66篇
  2015年   49篇
  2014年   51篇
  2013年   71篇
  2012年   140篇
  2011年   154篇
  2010年   84篇
  2009年   69篇
  2008年   146篇
  2007年   142篇
  2006年   163篇
  2005年   157篇
  2004年   149篇
  2003年   126篇
  2002年   87篇
  2001年   116篇
  2000年   101篇
  1999年   89篇
  1998年   49篇
  1997年   26篇
  1996年   24篇
  1995年   18篇
  1993年   17篇
  1992年   67篇
  1991年   70篇
  1990年   68篇
  1989年   65篇
  1988年   70篇
  1987年   68篇
  1986年   71篇
  1985年   83篇
  1984年   48篇
  1983年   38篇
  1982年   19篇
  1979年   24篇
  1978年   19篇
  1977年   22篇
  1975年   19篇
  1973年   19篇
  1971年   17篇
  1969年   24篇
  1968年   34篇
  1967年   20篇
排序方式: 共有3367条查询结果,搜索用时 15 毫秒
111.
Extratumoral lymphatic permeation (ly‐ext) has been reported as an independent poor prognostic factor for lung adenocarcinoma, but whether or not the number of ly‐ext foci is associated with prognosis and its relationship to the immune microenvironment is unclear. We counted the number of ly‐ext foci on pathological slides from patients with completely resected lung adenocarcinoma with ly‐ext, and divided them into two groups: a group with a high number of ly‐ext foci (ly‐ext high) and one with a low number of ly‐ext foci (ly‐ext low). Among the patients with ly‐ext, only a high number of ly‐ext foci was an independent poor prognostic factor. The 3‐year recurrence‐free survival (RFS) rate of the ly‐ext high group was significantly lower than that of the ly‐ext low group (14.7% vs. 50.0%, P < 0.01). Then, we analyzed the immune microenvironment of pT1 lung adenocarcinoma with ly‐ext (13 cases of ly‐ext high and 11 cases of ly‐ext low tumor) by immunohistochemistry using antibodies for stem cell markers (aldehyde dehydrogenase 1 A1 and CD44), tumor‐promoting mucin (MUC1), tumor‐infiltrating lymphocytes (CD4, CD8, FOXP3, and CD79a), and tumor‐associated macrophages (CD204). The number of CD8+ TILs within the primary lesion was significantly lower and the number of FOXP3+ TILs within the primary lesion was significantly higher in the ly‐ext high group (P < 0.05 and P < 0.01, respectively). Our results indicated that a high number of ly‐ext foci was an independent poor prognostic factor. Moreover, tumors with high numbers of ly‐ext foci had a more immunosuppressive microenvironment.  相似文献   
112.
AIMS: A novel blood purification material that we previously reported as a superantigen- and cytokine-adsorbing device (SCAD) was evaluated for its ability to adsorb unbound, unconjugated bilirubin (UUBil) in vitro and in vivo. METHODS: In albumin-containing buffer, UUBil was dissolved and circulated through the SCAD column. Also, bilirubin was infused into low-body weight newborn piglets and hemoperfused for 3 h over SCAD columns. RESULTS: In albumin-containing buffer, concentration of bilirubin decreased from 34 to 0.6 mg/dL within 5 h and the SCAD fiber turned brown, indicating that bilirubin was adsorbed onto the surface of the adsorbent and was not degraded during the circulation. Using the hyperbilirubinemia swine, clearances of total bilirubin (TBil), direct bilirubin (DBil), and indirect bilirubin (IdBil) were significantly higher (P<0.01) in the SCAD group compared with the control group. The clearances of TBil, DBil, and IdBil at 3 h after the initiation of the bilirubin infusion were 0.47, 0.53, and 0.45 mL/min, respectively, at a blood flow rate of 2.5 mL/min, and this result indicates that almost 20% of bilirubins were adsorbed to the SCAD column in a single passage. CONCLUSION: These results provide initial evidence that SCAD treatment is effective in the removal of UUBil and can be performed safely in newborn animals.  相似文献   
113.
Blue rubber bleb nevus syndrome (BRBNS) is a rare disorder showing venous malformations in the skin and gastrointestinal tract, and other internal organs. We encountered a patient with BRBNS in whom hemangiomas of the uterine cervix appeared during pregnancy. This was apparently the first reported occurrence. To avoid unexpected bleeding from hemangiomas, patients with BRBNS should be examined repeatedly for hemangiomas of the birth canal, and special care should be taken in deciding the mode of delivery.  相似文献   
114.
115.
116.
Follicular lymphoma (FL) is a germinal center-derived B-cell lymphoma that is known to proliferate in the intrafollicular region. However, lymphoma cells can be identified in the extrafollicular regions, which are related to disease dissemination. We purified the intrafollicular and extrafollicular regions of FL cells by laser microdissection and conducted microarray analysis in order to characterize the gene expression profiles of FL cells from both regions. BCL2 and genes of germinal B-cell markers clearly separated intrafollicular and extrafollicular regions of reactive follicular hyperplasia, suggesting the adequacy of the current analysis. In FL cases, cytokine-related genes were significantly enriched in extrafollicular regions compared with those in the intrafollicular regions. In intrafollicular regions of FL, cell-cycle–related genes were enriched. We found that the FL cells in the extrafollicular region more strongly expressed IL3RA and CXCL12 than those of intrafollicular regions. The cytokines might be also derived from stroma cells in the extrafollicular regions, which may initiate activation and migration of the tumor cells to this region. Our results suggest that FL cell interaction with surrounding stroma cells plays an important role in the pathophysiology of FL and that such interactions should be a good target for therapy.  相似文献   
117.
The interaction of CD47 and signal-regulatory protein alpha (SIRPα) induces “don't eat me signal”, leading suppression of phagocytosis. This signal can affect the clinical course of malignant disease. Although CD47 and SIRPα expression are associated with clinicopathological features in several neoplasms, the investigation for adult T-cell leukemia/lymphoma (ATLL) has not been well-documented. This study aimed to declare the association between CD47 and SIRPα expression and clinicopathological features in ATLL. We performed immunostaining on 73 biopsy samples and found that CD47 is primarily expressed in tumor cells, while SIRPα is expressed in non-neoplastic stromal cells. CD47 positive cases showed significantly higher FoxP3 (P = .0232) and lower CCR4 (P = .0214). SIRPα positive cases presented significantly better overall survival than SIRPα negative cases (P = .0132). SIRPα positive cases showed significantly HLA class I (P = .0062), HLA class II (P = .0133), microenvironment PD-L1 (miPD-L1) (P = .0032), and FoxP3 (P = .0229) positivity. In univariate analysis, SIRPα expression was significantly related to prognosis (Hazard ratio [HR] 0.470; 95% confidence interval [CI] 0.253-0.870; P = .0167], although multivariate analysis did not show SIPRα as an independent prognostic factor. The expression of SIRPα on stromal cells reflects activated immune surveillance mechanism in tumor microenvironment and induce good prognosis in ATLL. More detailed studies for gene expression or genomic abnormalities will disclose clinical and biological significance of the CD47 and SIRPα in ATLL.  相似文献   
118.
Analysis of anticancer immunity aids in assessing the prognosis of patients with breast cancer. From 250 operated breast cancers, we focused on serum levels of C‐C motif chemokine ligand 5 (CCL5), which is involved in cancer immune reactions. Serum levels of CCL5 were measured using a cytometric bead‐based immunoassay kit and CCL5 expression in cancer cells was determined using immunohistochemical staining. In addition, mRNA in cancer and stromal cells was analyzed by microdissection and comparison with the public dataset. Disease‐free survival (DFS) of patients with high CCL5 levels (cut‐off, 13.87 ng/mL; n = 192) was significantly better than those with low CCL5 levels (n = 58; hazard ratio, 0.20; 95% confidence interval, 0.10‐0.39; P < .0001). An improved overall survival was observed in patients with high CCL5 levels compared to those with low CCL5 levels (P = .024). On the contrary, high immunohistochemical expression of CCL5 in cancer cells was significantly associated with decreased DFS. As serum CCL5 levels did not correlate with CCL5 expression in cancer cells and the relative expression of mRNA CCL5 was elevated in stromal cells in relation to cancer cells, serum CCL5 might be derived not from cancer cells, but from stromal cells. Expression of CCL5 in serum, but not in cancer cells, might contribute to improved patient prognosis mediating through not only immune reaction, but through other mechanisms. Determination of circulating CCL5 levels could be useful for predicting patient prognosis.  相似文献   
119.
Both dermatopathic lymphadenopathy (DL) and immunoglobulin G4-related disease (IgG4-RD) are frequently complicated with allergic diseases. However, the relationship between DL and IgG4-RD is not well known. To clarify this relationship on the basis of clinical and pathological findings, including IgG4-positive (IgG4+) plasma cell infiltration in lymph nodes (LNs) of DL patients, we analyzed LNs of 11 DL patients using immunostaining of IgG, IgG4, forkhead box P3 (FOXP3), transforming growth factor (TGF)-β, interferon (IFN)-γ, and matrix metalloproteinase (MMP)-1, MMP-8, and MMP-13. Toluidine blue staining was also performed to identify mast cells. Of 3 patients with a high ratio of IgG4+/IgG+ cells (>40%) and elevated serum IgG4 levels, 2 developed IgG4-RD, whereas the other patient did not. Of 8 patients with a low ratio of IgG4+/IgG+ cells (<40%) or no infiltration of IgG4+ cells, 5 who could be followed did not develop IgG4-RD. The numbers of mast cells were similar to those of TGF-β-positive cells, and serial sections showed that mast cells possibly produce TGF-β. LNs of DL patients with a high ratio of IgG4+/IgG+ cells had significantly more mast cells and TGF-β-positive cells than those of patients with a low ratio of IgG4+/IgG+ cells or no infiltration of IgG4+ cells. However, no fibrosis was observed in LNs of both groups. IFN-γ was positive in interdigitating dendritic cells, Langerhans cells, and macrophages. MMP-1, MMP-8, or MMP-13 was expressed in macrophages. The lack of fibrosis in LNs may have been due to the production of IFN-γ, MMP-1, MMP-8, or MMP-13. Thus, DL with increased IgG4+ cells seems to be a phenotype of IgG4-RD in LNs.  相似文献   
120.
To evaluate the correlation between predicted postoperative lung function and postoperative respiratory morbidity, 156 patients with lung cancer who underwent resection were classified into four groups based on the degree of postoperative problems: Group 1--no problems (116 patients); Group 2--retention of sputum or atelectasis requiring bronchofiberscopy two or more times (17 patients); Group 3--tracheostomy or mechanical ventilation for more than 2 days or both (14 patients); and Group 4--postoperative death (9 patients). The mean ages of Groups 2, 3, and 4 were significantly (p less than 0.05) higher than the mean age of Group 1. The predicted postoperative lung function (F) was assessed by the formula F = [1-(b-n)/(42-n)] x f, where f is the preoperative vital capacity or forced expiratory volume in one second, b is the number of subsegments of the resected lung lobe, and n is the number of subsegments obstructed by the tumor, which was assessed by the findings on the chest tomogram, on the bronchogram, at bronchofiberscopy, or a combination of these. The total number of subsegments was assumed to be 42. The predicted postoperative % FEV1 was 65.1 +/- 19.3% in Group 1,55.3 +/- 10.6% in Group 2,37.6 +/- 12.1% in Group 3, and 42.3 +/- 18.4% in Group 4. It was significantly (p less than 0.05) different between all the groups except between Groups 3 and 4. All 10 patients with a predicted postoperative % FEV1 of less than 30% were in Groups 3 and 4. We conclude that special attention to postoperative management is needed for patients whose predicted postoperative %FEV1 is lower than 30%.  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