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   1072篇
  免费   90篇
  国内免费   19篇
儿科学   79篇
妇产科学   5篇
基础医学   130篇
口腔科学   63篇
临床医学   122篇
内科学   189篇
皮肤病学   46篇
神经病学   27篇
特种医学   246篇
外科学   82篇
综合类   29篇
预防医学   52篇
眼科学   13篇
药学   29篇
  1篇
肿瘤学   68篇
  2021年   6篇
  2020年   9篇
  2019年   8篇
  2018年   15篇
  2017年   6篇
  2016年   12篇
  2015年   27篇
  2014年   23篇
  2013年   43篇
  2012年   22篇
  2011年   20篇
  2010年   53篇
  2009年   52篇
  2008年   23篇
  2007年   33篇
  2006年   24篇
  2005年   26篇
  2004年   16篇
  2003年   26篇
  2002年   20篇
  2001年   16篇
  2000年   5篇
  1999年   22篇
  1998年   81篇
  1997年   78篇
  1996年   60篇
  1995年   53篇
  1994年   37篇
  1993年   45篇
  1992年   7篇
  1991年   23篇
  1990年   15篇
  1989年   42篇
  1988年   35篇
  1987年   25篇
  1986年   18篇
  1985年   18篇
  1984年   9篇
  1983年   12篇
  1982年   14篇
  1981年   14篇
  1980年   15篇
  1978年   13篇
  1977年   11篇
  1976年   10篇
  1975年   8篇
  1971年   3篇
  1969年   6篇
  1968年   3篇
  1966年   3篇
排序方式: 共有1181条查询结果,搜索用时 17 毫秒
101.
102.
Expression of bcl-xL can confer a multidrug resistance phenotype   总被引:14,自引:3,他引:14  
Minn  AJ; Rudin  CM; Boise  LH; Thompson  CB 《Blood》1995,86(5):1903-1910
It has been suggested that genes that regulate apoptotic cell death may play an important role in determining the sensitivity of tumor cells to chemotherapy. We have recently cloned a member of the bcl-2 family, bcl- x. To test whether bcl-XL expression affects the sensitivity of tumor cells to chemotherapy, we have created stable cell lines overexpressing bcl-XL and have tested these cells for resistance to cell death induced by metabolic inhibitors and chemotherapeutic agents. Bcl-XL expression dramatically reduces the cytotoxicity of bleomycin, cisplatin, etoposide, vincristine, hygromycin B, and mycophenolic acid for up to 4 days in culture. Bcl-XL does not prevent cells from undergoing cell cycle arrest in response to these drugs, but rather prevents treated cells from undergoing apoptosis. Cell-cycle analysis on cells treated with the chemotherapeutic agents bleomycin, cisplatin, etoposide, and vincristine, show that the drugs cause growth arrest in different positions within the cell cycle. Bcl-XL expressing cells treated with chemotherapeutic drugs retain their proliferative ability after the drugs are removed. Interestingly, vincristine-treated cells expressing bcl-XL become polyploid after drug removal. These data show that bcl-XL protects cells from a wide variety of apoptotic stimuli, acts in multiple positions within the cell cycle, and confers a multidrug resistance phenotype. The ability of bcl-XL to prevent apoptotic cell death in response to chemotherapy-induced DNA damage and cell-cycle arrest may contribute to the accumulation of chromosomal aberrations within tumors. The expression of bcl-XL in tumor cells is likely to be an important indicator of chemotherapeutic efficacy.  相似文献   
103.

Background

In independent studies, IBD, IBS and HCV have each been associated with a substantially increased risk of psychological problems such as depression and anxiety and impairment of quality of life compared to the general healthy population. However, the relative psychological burden for each of these diagnoses is unknown as it has never been compared contemporaneously at one institution. Current local data are therefore needed to enable an evidence-based allocation of limited clinical psychological resources.

Methods

Overall, 139 outpatients (64 IBD, 41 HCV, and 34 IBS) were enrolled in this cross-sectional study. The HADS, SCL90, SF-12 and appropriate disease-specific activity measures were administered. Differences between groups were assesed with ANOVA, the Chi-Square test and the independent samples t-test (two-tailed).

Results

Each of the three groups had significantly lower quality of life than the general population (p < 0.05). Overall, a total of 58 (42%) participants met HADS screening criteria for anxiety and 26 (19%) participants for depression. The HCV group had a significantly higher prevalence of depression than either of the other groups (HCV = 34%, IBS = 15% and IBD = 11%, p = 0.009). In the SCL90, the three disease groups differed on 7 out of 12 subscales. On each of these subscales, the HCV group were most severely affected and differed most from the general population.

Conclusion

Patients with these common chronic gastrointestinal diseases have significant impairment of quality of life. Anxiety is a greater problem than depression, although patients with HCV in particular, should be regularly monitored and treated for co-morbid depression. Evaluation of specific psychological interventions targeting anxiety is warranted.
  相似文献   
104.
Push enteroscopy in the investigation of small-intestinal disease   总被引:3,自引:0,他引:3  
We report our experience with small-bowel push enteroscopy in 50 patients. The indications for push enteroscopy were: anaemia/occult gastrointestinal bleeding (22 patients); overt gastrointestinal bleeding (17 patients); abnormal small-bowel radiology (8 patients) and miscellaneous (3 patients). In those with undiagnosed gastrointestinal bleeding/anaemia, abnormalities were detected in 24/39 patients (62%): small bowel arteriovenous malformations (AVMs) were detected in 19 (49%), and five (13%) had lesions in the upper gastrointestinal tract. Seventeen patients had heater-probe ablation therapy of vascular lesions: nine patients had small-intestinal lesions, four patients gastric lesions, and four patients combined gastric and small- intestinal lesions. In those with abnormal small-bowel radiology, abnormalities were detected in 6/8 patients. We conclude that (i) push enteroscopy can establish a diagnosis in a high proportion of patients with gastrointestinal bleeding; (ii) heater-probe ablation therapy of vascular lesions can be performed routinely at the time of enteroscopy; (iii) a significant proportion of patients (9/50) referred for enteroscopy with undiagnosed gastrointestinal bleeding have lesions in the stomach/proximal duodenum missed at diagnostic endoscopy. Push enteroscopy is a valuable diagnostic and therapeutic endoscopic procedure.   相似文献   
105.
Objective. To evaluate the therapeutic response to sumatriptan in the acute migraine attack. Material and methods. Two hundred and thirty migraineurs diagnosed by their general practitioners in accordance with their usual practice were included in the study. The patients treated two migraine attacks at home by subcutaneous injection of sumatriptan or placebo for the first attack and the alternative medication, i.e. placebo or sumatriptan, for the second attack (crossover). Following treatment, a neurology resident interviewed and examined the patients, Results. When sumatriptan was compared to placebo, significantly more of the 209 evaluable patients reported headache relief at I h (56% vs 8%, p < 0.001) and 2 h (62% vs 15%, p < 0.001) after the first injection. Resolution of nausea, photophobia, and phonophobia was significantly more common in patients on sumatriptan than in those on placebo ( p < 0.001 for all comparisons). The adverse events were usually transient and of mild or moderate severity; however, three patients withdrew due to adverse events. Ninety-five percent of patients evaluated by a neurology resident met the IHS criteria for migraine. Conclusion. In general practice, sumatriptan taken subcutaneously using an autoinjector at home was an effective and well tolerated acute treatment for migraine.  相似文献   
106.
SUMMARY A case is reported of pseudohyperphosphataemia in association with a monoclonal gammopathy of undetermined significance.  相似文献   
107.
108.
AIMS: In several observational studies, revascularization is associated with substantial reduction in mortality in patients with non-ST-segment elevation acute coronary syndrome (nSTE-ACS). This has strengthened the belief that routine early angiography would lead to a reduction in mortality. We investigated the association between actual in-hospital revascularization and long-term outcome in patients with nSTE-ACS included in the ICTUS trial. METHODS AND RESULTS: The study population of the present analysis consists of ICTUS participants who were discharged alive after initial hospitalization. The ICTUS trial was a randomized, controlled trial in which 1200 patients were randomized to an early invasive or selective invasive strategy. The endpoints were death from hospital discharge until 4 year follow-up and death or spontaneous myocardial infarction (MI) until 3 years. Among 1189 patients discharged alive, 691 (58%) underwent revascularization during initial hospitalization. In multivariable Cox regression analyses, in-hospital revascularization was independently associated with a reduction in 4 year mortality and 3 year event rate of death or spontaneous MI: hazard ratio (HR) 0.59 [95% confidence interval (CI) 0.37-0.96] and 0.46 (95% CI 0.31-0.68). However, when intention-to-treat analysis was performed, no differences in cumulative event rates were observed between the early invasive and selective invasive strategies: HR 1.10 (95% CI 0.70-1.74) for death and 1.27 (95% CI 0.88-1.85) for death or spontaneous MI. CONCLUSION: The ICTUS trial did not show that an early invasive strategy resulted in a better outcome than a selective invasive strategy in patients with nSTE-ACS. However, similar to retrospective analyses from observational studies, actual revascularization was associated with lower mortality and fewer MI. Whether an early invasive strategy leads to a better outcome than a selective invasive strategy cannot be inferred from the observation that revascularized patients have a better prognosis in non-randomized studies.  相似文献   
109.
In this case report we present an elderly patient who was referred to our hospital with recurrent episodes of cholangitis that persisted after placement of five metal stents for a distal common bile duct (CBD) stenosis.All metal stents were endoscopically removed from the CBD by forceps after balloon dilatation of the papilla. A profoundly dilated CBD with sludge and concrements was seen. To ensure adequate bile drainage an enteral metal stent was inserted in the CBD. This case shows that proximally migrated uncovered metal stents in the CBD can be safely removed endoscopically under certain circumstances. We suggest that in the case of a CBD drainage problem due to an extremely dilated CBD, placement of an enteral metal stent in the CBD could be considered, especially in patients who are unfit for surgery.  相似文献   
110.
From experiments with purified proteins, it has been concluded that factor XIa (FXIa) is inhibited in plasma mainly by alpha 1-antitrypsin (a1AT), followed by antithrombin III (ATIII), C1-inhibitor (C1Inh), and alpha 2-antiplasmin (a2AP). However, the validity of this concept has never been studied in plasma. We established the relative contribution of different inhibitors to the inactivation of FXIa in human plasma, using enzyme-linked immunosorbent assays (ELISAs) for the quantification of complexes of FXIa with a1AT, C1Inh, a2AP, and ATIII. We found that 47% of FXIa added to plasma formed complexes with C1Inh, 24.5% with a2AP, 23.5% with a1AT, and 5% with ATIII. The distribution of FXIa between these inhibitors in plasma was independent of whether FXIa was added to plasma, or was activated endogenously by kaolin, celite, or glass. However, in the presence of heparin (1 or 50 U/mL), C1Inh appeared to be the major inhibitor of FXIa, followed by ATIII. Furthermore, at lower temperatures, less FXIa-C1Inh and FXIa-a1AT complexes but more FXIa-a2AP complexes were formed. These data demonstrate that the contribution of the different inhibitors to inactivation of FXIa in plasma may vary, but C1Inh is the principal inhibitor under most conditions.  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