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   4162篇
  免费   115篇
  国内免费   23篇
耳鼻咽喉   79篇
儿科学   35篇
妇产科学   87篇
基础医学   766篇
口腔科学   66篇
临床医学   326篇
内科学   901篇
皮肤病学   83篇
神经病学   250篇
特种医学   218篇
外科学   426篇
综合类   19篇
一般理论   4篇
预防医学   179篇
眼科学   19篇
药学   472篇
  1篇
中国医学   65篇
肿瘤学   304篇
  2024年   13篇
  2023年   37篇
  2022年   88篇
  2021年   138篇
  2020年   73篇
  2019年   88篇
  2018年   106篇
  2017年   69篇
  2016年   119篇
  2015年   183篇
  2014年   204篇
  2013年   232篇
  2012年   377篇
  2011年   337篇
  2010年   216篇
  2009年   183篇
  2008年   251篇
  2007年   263篇
  2006年   232篇
  2005年   220篇
  2004年   153篇
  2003年   136篇
  2002年   101篇
  2001年   98篇
  2000年   69篇
  1999年   69篇
  1998年   29篇
  1997年   15篇
  1996年   25篇
  1995年   15篇
  1994年   10篇
  1993年   9篇
  1992年   21篇
  1991年   11篇
  1990年   7篇
  1989年   7篇
  1988年   5篇
  1987年   5篇
  1986年   9篇
  1985年   9篇
  1984年   10篇
  1981年   3篇
  1980年   3篇
  1979年   3篇
  1978年   8篇
  1973年   4篇
  1972年   4篇
  1971年   6篇
  1970年   4篇
  1968年   4篇
排序方式: 共有4300条查询结果,搜索用时 15 毫秒
31.
This study retrospectively evaluated the effectiveness of an open reduction and internal fixation of a tension band wiring technique for treating displaced or unstable comminuted distal ulnar shaft fractures without a radial fracture. Ten patients were treated for an isolated distal ulnar shaft fracture. There were 6 cases of a fracture 2.5 cm below the lower end of the ulna, and 4 cases with the fracture being 2.5 cm to 5 cm away from the lower end of the ulna. The authors classified the fractures of the distal ulnar into 3 types: a type I-simple fracture, a type II-comminuted fracture without a distal radioulnar joint (DRUJ) involvement, and a type III- comminuted fracture with DRUJ involvement. There were 3 cases of a type I fracture, 4 of type II and 3 of type III. The open reduction and internal fixation using tension band wiring were performed in 10 of these cases. After the operation, the wrist was placed in a cast for six weeks before active movement was allowed. The clinical results were excellent in 7 cases, good in 2 and poor in 1. In conclusion, tension band wiring surgery is recommended for treating an isolated distal ulnar with unreduced displaced fractures, in a comminuted fracture that cannot be maintained by a closed reduction and when there is the potential encroachment of fracture fragments in the DRUJ.  相似文献   
32.
Chang BC  Lim SH  Kim DK  Seo JY  Cho SY  Shim WH  Chung N  Kim SS  Cho BK 《The Journal of heart valve disease》2001,10(2):185-194; discussion195
BACKGROUND AND AIM OF THE STUDY: The clinical evaluation and comparison of St. Jude Medical (SJM) and CarboMedics (CM) prosthetic heart valves implanted between 1988 and 1997 is presented. METHODS: In total, 648 SJM valves were implanted in 641 patients, and 601 CM valves in 591 patients. There were 684 mitral valve replacements, 256 aortic valve replacements, 252 mitral and aortic (double) valve replacements, 16 triple valve replacements, and 41 other tricuspid-related valve replacements. Total follow up was 98%. The overall incidence of valve-related events was compared before and after establishment of a 'valve clinic' in 1993. RESULTS: The overall hospital mortality was 3.4%; late mortality was 8.2%. The five- and ten-year survival for all patients was 92.1% and 86.2%, respectively. There were 31 episodes of thromboembolism in 27 patients (including valve thrombosis in three), 21 episodes of bleeding events in 20 patients, and 18 re-replacements of implanted valves. No structural valve deterioration was observed. Freedom from thromboembolism was 97.8% at five years and 96.3% at ten years; freedom from bleeding episodes was 98.1% and 97.6%, respectively. In terms of hospital and late mortality, and incidence of thromboembolism, hemorrhagic episodes and structural valve failure, no statistically significant differences were found between the SJM and CarboMedics patient groups. Freedom from thromboembolism was 96.7% at five years before initiation of an intensive follow up program, and 99.0% thereafter (p = 0.031). In contrast, freedom from bleeding episodes fell from 99.3% to 96.1% during the same time period (p = 0.0004). CONCLUSION: Both the SJM and CM prosthetic heart valves performed well in our study, and no discernible differences in clinical performance of the two valves were detected. The intensive follow up program resulted in a reduced incidence of thromboembolism, but an increased number of bleeding complications. An optimum anticoagulation regimen to manage these two conflicting problems has yet to be elucidated.  相似文献   
33.
The purpose of this study was to describe the clinical, computed tomographic (CT), and pathologic findings of large cell neuroendocrine carcinoma (LCNEC) of the lung. CT and pathologic findings as well as clinical features of surgically proven LCNEC of the lung were reviewed retrospectively in 11 consecutive patients (eight men and three women; mean age, 63 years; range, 44-77 years). Chest CT showed peripheral mass or nodule (n = 8) and central mass with distal atelectasis (n = 3). Six tumors were accompanied by mediastinal (n = 3) and hilar (n = 3) lymph node enlargement at CT. On pathologic examination, all resected tumors showed necrosis of variable extent (mean: 38%, range; 10-70%). The areas of intrinsic lipoid pneumonia and tumor emboli in two patients appeared at CT as areas of ground-glass opacity surrounding the tumor. Mediastinal nodal metastases were seen in three (27%) patients. Pathologic staging of 11 patients was IB in six, IIA in one, IIB in one, IIIA in two, and IIIB in one. Follow-up data showed extrathoracic metastases in four patients at mean follow-up period of 15 months. One patient died of distant metastasis 5 months after the surgery. CT findings of LCNEC of the lung are nonspecific and similar to those of other non-small cell lung cancers and extrathoracic metastasis is seen in approximately one third of the patients with follow-up study.  相似文献   
34.
In our previous study we demonstrated that acupuncture at Shenmen (HT7) points suppressed a decrease of accumbal dopamine (DA) release in ethanol-withdrawn rats. Furthermore, here we found that it inhibited behavioral withdrawal signs of ethanol. In an effort to better understand the mechanisms underlying this inhibition, the potential role of GABA receptor system in acupuncture was investigated. Male Sprague–Dawley rats were treated with 3 g/kg/day of ethanol (20%, w/v) or saline by intraperitoneal injection for 21 days. Following 48 or 72 h of ethanol withdrawal, acupuncture was applied at bilateral HT7 for 1 min. The selective GABAA antagonist bicuculline and the selective GABAB antagonist SCH 50911 were injected intraperitoneally 20 min before acupuncture, respectively. Importantly, suppressive effects of acupuncture on DA deficiency were completely abolished by SCH 50911, but not by bicuculline, whereas ameliorating effects of acupuncture on ethanol withdrawal syndrome were completely blocked either by SCH 50911 or bicuculline. These results suggest that acupuncture at specific acupoint HT7 may normalize the DA release in the mesolimbic system and attenuate withdrawal syndrome through the GABAB receptor system in ethanol-withdrawn rats.  相似文献   
35.

Background and Aim

Esophagogastroduodenoscopy (EGD) is recommended at 2-year intervals in countries with a high prevalence of gastric cancer. The aim of this study was to determine whether interval gastric cancers that develop within 2 years of a previous complete screening are associated with microsatellite instability (MSI).

Methods

Newly diagnosed gastric cancer patients who had undergone gastrectomy were included. Of these 459 patients, 177 were classified as interval gastric cancer since they were diagnosed within 2 years of a previous EGD. Noninterval gastric cancer patients were subclassified into 65 patients who underwent previous EGD between the past 2 and 10 years and 217 patients without EGD during the last 10 years. Analysis for MSI was conducted using two mononucleotide and three dinucleotide markers.

Results

MSI was found more frequently in noninterval gastric cancers than in interval gastric cancers (p = 0.009). Interval gastric cancers were associated with a higher prevalence of early gastric cancer (p = 0.006), smaller size (p < 0.001), and lower TNM stages (p = 0.006). On logistic regression analysis, noninterval gastric cancers were related to MSI (p = 0.010) and larger size (≥4 cm) (p = 0.009). Subjects with interval gastric cancer showed better survival than those with noninterval gastric cancer (p = 0.006).

Conclusions

During a 2-year screening interval, noninterval gastric cancers tend to be larger, more advanced, and associated with MSI. Biannual EGD screening is effective for detecting small gastric cancers at an early stage, but is not useful in detecting gastric cancers with MSI.  相似文献   
36.

Background

Endoscopic submucosal dissection is applied in selected cases of signet ring cell early gastric cancer. However, factors related to curability of signet ring cell early gastric cancer with this method have not been fully evaluated. Our aim was to evaluate factors related to incomplete resection in signet ring cell early gastric cancer with endoscopic submucosal dissection.

Methods

A retrospective analysis was performed on a total of 126 consecutive patients with signet ring cell early gastric cancer who had undergone endoscopic submucosal dissection at the Severance Hospital in Korea, between March 2007 and March 2012. The clinical outcomes were reviewed and factors related to incomplete resection were analysed.

Results

Multivariate analysis showed that large tumour size was the only significant factor related to incomplete resection (P = 0.006; hazard ratio, 1.040; 95% confidence interval, 1.101–1.084). In addition, large tumour size was the only significant factor related to endoscopic size underestimation (P < 0.001; hazard ratio, 1.391; 95% confidence interval, 1.221–1.586). The rate of endoscopic size underestimation was significantly higher in tumours with a size ≥20 mm (P < 0.001).

Conclusions

To improve the curability of signet ring cell early gastric cancer with endoscopic submucosal dissection, larger tumours (especially tumour with a size ≥20 mm) should be resected with a larger margin.  相似文献   
37.
Heo SK  Yun HJ  Noh EK  Park WH  Park SD 《Immunology letters》2008,120(1-2):57-64
Inflammation is an important event in the development of vascular diseases such as hypertension, atherosclerosis, and restenosis. In addition, the stimulation of Toll-like receptor 4 (TLR4) by lipopolysaccharide (LPS) induces the release of critical proinflammatory cytokines that activate potent immune responses. In this study, LPS was found to induce TLR4 expression and increased nitric oxide (NO) production by increasing the expression of inducible nitric oxide synthase (iNOS). Furthermore, LPS was found to induce interleukin (IL)-8 and vascular endothelial growth factor (VEGF) production, as well as intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression. Taken together, these results indicate that LPS induces inflammatory responses in HASMC. Moreover, NOS inhibitor (L-NAME) and anti-TLR 4mAb reduced the LPS-induced NO, IL-8 and VEGF production and ICAM-1 expression. Additionally, TLR4 expression was reduced by NOS inhibitor. Taken together, these results indicate that LPS-induced inflammatory responses are regulated by TLR4 expression and NO production.  相似文献   
38.
39.
T-cell lymphomas are a biologically heterogeneous group of diseases with varying clinical presentations and outcomes. We tried to understand the effect of Epstein-Barr virus (EBV) on lymphogenesis, prognostic factors and drug resistance of T-cell lymphomas, and to establish their relationship with international prognostic factors. Formalin-fixed paraffin-embedded tissue sections from 35 patients (12 women and 23 men) with T-cell lymphomas were examined to detect the presence of EBV using RNA in situ hybridization for EBV-encoded small nuclear RNA (EBER) 1/2 and immunohistochemical stain for latent membrane protein (LMP)-1. We also tried to establish the expression of p53 and P-glycoprotein (P-gp) using immunohistochemistry. The distribution according to the subgroup was: two T-lymphoblastic lymphomas, 13 NK/T-cell lymphomas, one angioimmunoblastic T-cell lymphoma, 17 peripheral T-cell lymphomas, unspecified, and two anaplastic large cell lymphomas. The EBER was detected in 15 of 35 T-cell lymphomas (42.9%) and among these it was detected in five of 17 nodal lymphomas (29.4%) and 10 of 18 extranodal lymphomas (55.6%). There was close correlation between EBER positivity and NK/T-cell lymphoma (P = 0.032). Expression of LMP was found in a proportion of tumor cells in seven of the 15 EBER-positive cases (46.7%). There was no correlation between EBER expression and complete response (CR rate), but coexpression of EBER and p53 was associated with treatment failure (P = 0.047). The 18 patients (51.4%) with p53 expression had significantly poorer outcomes compared with the 17 patients without p53 expression (CR rate, P < 0.0005; overall survival, P = 0.0102). Twenty of 35 patients (57.1%) were positive for P-gp expression. P-gp expression was significantly associated with treatment failure (P = 0.001) and overall survival (P = 0.0089). Seventeen of 35 patients (48.6%) treated with systemic chemotherapy or radiation therapy achieved a CR after initial treatment. When the prognostic factors were grouped using the international prognostic index, the CR rate was 58.8% for the low risk group, 50.0% for the low-intermediate risk group, 14.3% for the high-intermediate risk group, and 0% for the high risk group. In conclusion, high incidence of EBV was detected among Korean patients with T-cell lymphomas. Our study supports the prediction that patients who express p53 and P-gp have a poorer prognosis than those who do not and this should be considered when treatment strategies for individual patients are selected.  相似文献   
40.
An efficient and quantitative tool for rapid assessment of human immunodeficiency virus (HIV)-induced cellular immune responses is important for resource-limited settings, such as in sub-Saharan Africa. Modifications are required to previously reported methods for evaluating ex-vivo antigen-specific cellular responses based on direct recombinant vaccinia virus (rVV) stimulation of peripheral blood mononuclear cells (PBMCs) by enzyme linked immunosorbent assay (ELISPOT) and by flow cytometry intracellular cytokine assay (ICA). We made such modifications in order to detect specific responses and compared quantitative cellular immune responses in HIV-1 and HIV-2 infected Gambians. The sensitivity of the rVV-based ELISPOT assay was on average 1.25 interferon (IFN)-gamma spot forming cells (SFC) per 50 000 PBMCs specific for either infection, and 5 IFN-gamma-secreting CD8+ T cells/50 000 in the ICA. The level of IFN-gamma SFC detected by ELISPOT and by ICA were correlated (P < 0.02). ICA detected pol-specific responses in 88% and 67% of HIV-1 and HIV-2 subjects, respectively, and gag-specific responses in more than 80% of both infections. Lower proportions of responders were obtained with ELISPOT, for which pol responses were present in 60% of HIV-1 and 46% of HIV-2 infected patients, and gag responses in 55% and 69%, respectively. The assays did not show any significant difference in cellular immune responses between HIV-1 and HIV-2 infected subjects with CD4% >or= 20%. These outcomes are comparable with results obtained using standard techniques and thus this method is a suitable, rapid and less expensive assessment of cellular immunity.  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