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   710篇
  免费   55篇
  国内免费   14篇
耳鼻咽喉   9篇
儿科学   8篇
妇产科学   28篇
基础医学   143篇
口腔科学   68篇
临床医学   51篇
内科学   196篇
皮肤病学   14篇
神经病学   52篇
特种医学   22篇
外科学   72篇
综合类   13篇
预防医学   24篇
眼科学   19篇
药学   20篇
中国医学   1篇
肿瘤学   39篇
  2022年   10篇
  2021年   18篇
  2020年   8篇
  2019年   17篇
  2018年   23篇
  2017年   17篇
  2016年   16篇
  2015年   14篇
  2014年   27篇
  2013年   26篇
  2012年   43篇
  2011年   38篇
  2010年   24篇
  2009年   28篇
  2008年   27篇
  2007年   38篇
  2006年   40篇
  2005年   23篇
  2004年   30篇
  2003年   30篇
  2002年   32篇
  2001年   31篇
  2000年   41篇
  1999年   15篇
  1998年   11篇
  1997年   20篇
  1996年   10篇
  1995年   10篇
  1994年   10篇
  1993年   3篇
  1992年   6篇
  1991年   4篇
  1990年   6篇
  1989年   10篇
  1987年   6篇
  1986年   5篇
  1985年   3篇
  1984年   5篇
  1983年   6篇
  1982年   4篇
  1981年   2篇
  1980年   2篇
  1979年   9篇
  1977年   8篇
  1976年   5篇
  1975年   3篇
  1971年   2篇
  1958年   2篇
  1957年   2篇
  1956年   2篇
排序方式: 共有779条查询结果,搜索用时 15 毫秒
31.
ObjectiveTo assess the association of the polymorphisms of the interleukin-18 (IL-18) gene with rheumatoid arthritis (RA) and with risk factors for cardiovascular diseases (CVD).MethodsThis sample comprised 97 patients with RA and 151 healthy controls. In the patients, risk factors for CVD were analyzed, such as cholesterol levels, arterial hypertension, smoking habit, C-reactive protein (CRP) level, and rheumatoid factor. DNA was extracted and the single nucleotide polymorphisms (SNP) at the ?607C/A and ?137G/C positions of the IL-18 gene were assessed in both groups. The Hardy-Weinberg equilibrium (HWE) was calculated and the odds ratio (OR) test performed, considering a 95% CI and P < 0.05.ResultsThe frequencies of the ?607A allele in patients with RA and in controls were 0,443 and 0.424, respectively, and of the ?137C allele, 0.304 and 0.291, respectively. The genotype frequencies were in HWE, except for controls in the ?137 locus (P = 0.006). Association of the polymorphisms of the IL-18 gene was found with neither RA nor risk factors for CVD, including cholesterol level and CRP (P > 0.05). In addition, more smokers were found among patients with RA as compared with controls (OR = 1.691; P = 0.088), and the CRP levels were slightly higher in patients who smoked than in patients who did not (OR = 2.673; P = 0.061).ConclusionsIn this sample of patients with RA in the South of Brazil, association of the polymorphisms of the IL-18 gene was observed with neither RA nor risk factors for CVD.  相似文献   
32.

Background and aims

Endoscopic placement of enteral self-expandable metallic stents is an alternative to surgical gastrojejunostomy (GJ) for palliation of malignant gastric outlet obstruction (GOO). Factors associated with clinical outcomes are not known. The aims of this study are to compare the overall complication rate and effectiveness (duration of oral intake) between endoscopic stenting (ES) and GJ in patients with GOO and identify predictors of clinical outcomes.

Patients and methods

This was a retrospective cohort study at a single tertiary academic center. Patients who underwent ES or GJ for treatment of GOO between 1/2001 and 12/2010 were identified using an institutional claims database. The electronic medical records for each patient were reviewed. Univariate and multivariate logistic regression analyses were performed to study the association of treatment outcomes with patient factors and cancer therapy.

Results

120 patients had ES while 227 had GJ. Technical success was higher for GJ (99 vs. 96 %, p = 0.004). Complication rates were higher in the GJ group (22.10 vs. 11.66 %, p = 0.02). Reintervention was more common with ES [adjusted odds ratio (OR) 9.18, p < 0.0001]. Mean length of hospital stay (LOHS) was shorter (adjusted p = 0.005) in the ES compared with the GJ group. However, mean hospital charges, including reinterventions, were greater in the ES group (US $34,250 vs. US $27,599, p = 0.03). ES and GJ had comparable reintervention-free time in patients who had reintervention (88 vs. 106 days, respectively, p = 0.79). Chemotherapy [adjusted hazard ratio (HR) 3 > 0.57, p = 0.04] and radiation therapy (adjusted HR 0.35, p = 0.03) were associated with significantly longer duration of oral intake after ES or GJ.

Conclusion

ES is associated with fewer complications, shorter LOHS, but higher reintervention rates and overall charges.  相似文献   
33.

Background

Parenchymal-sparing pancreatic surgery is ideal for lesions such as small pancreatic neuroendocrine tumors (PanNET). However, precise localization of these small tumors at surgery can be difficult. The placement of fiducials under endoscopic ultrasound (EUS) guidance (EUS-F) has been used to direct stereotactic radiation therapy for pancreatic adenocarcinoma. This report describes two cases in which placement of fiducials was used to guide surgical resection. This study aimed to assess the feasibility, safety, and efficacy of using EUS-F for intraoperative localization of small PanNETs.

Methods

A retrospective study analyzed two consecutive patients with small PanNETs who underwent EUS-F followed by enucleation in a tertiary-care referral hospital. The following features were examined: technical success and complication rates of EUS-F, visibility of the fiducial at the time of surgery, and fiducial migration.

Results

In the study, EUS-F was performed for two female patients with a 7-mm and a 9-mm PanNET respectively in the uncinate process and neck of the pancreas. In both patients, EUS-F was feasible with two Visicoil fiducials (Core Oncology, Santa Barbara, CA, USA) placed either within or adjacent to the tumors using a 22-gauge Cook Echotip needle. At surgery, the fiducials were clearly visible on intraoperative ultrasound, and both the tumor and the fiducials were successfully enucleated in both cases. No complications were associated with EUS-F, and no evidence of pancreatitis was shown either clinically or on surgical pathology. This investigation had the limitations of a small single-center study.

Conclusions

For patients undergoing enucleation, EUS-F is technically feasible and safe and aids intraoperative localization of small PanNETs.  相似文献   
34.

Purpose

In in vitro maturation (IVM) cycles primed with human chorionic gonadotropin (hCG), both immature and mature oocytes are retrieved from antral follicles sized 8–12 mm. Using time-lapse microscopy, we compared the morphokinetic behavior of embryos developed from oocytes matured in vivo and in vitro, testing the hypothesis that IVM affects preimplantation development. Furthermore, we extended the morphokinetic analysis of these embryos by a comparison with embryos obtained in stimulated assisted reproduction technology (ART) cycles.

Methods

In IVM cycles primed with follicle-stimulating hormone (FSH)/hCG, prior to sperm microinjection, oocytes surrounded by an expanded cumulus at retrieval and presumably mature (EC-MII) were incubated for 6 h, while immature oocytes enclosed in a compact cumulus (CC) were matured in vitro for 30 h. The morphokinetics of embryos selected for transfer or cryopreservation, derived from EC-MII and CC oocytes, were comparatively and retrospectively analyzed in terms of cleavage times (t2, t3, t4, t5, and t8) and intervals (cc2, cc3, s2, s3). For further comparison, the morphokinetics of embryos selected for transfer or cryopreservation (ICSI) or giving rise to ongoing pregnancies (model) in stimulated ART cycles was also assessed.

Results

The morphokinetic behavior of EC-MII and CC embryos was entirely comparable, as suggested by the absence of statistical differences in the averages of all cleavage times and intervals. Almost all cleavage and interval times were also similar between EC-MII, CC, ICSI, and model groups, with the exception of t4 and s2, which were delayed and longer, respectively, in embryos generated in IVM cycles (EC-MII and CC).

Conclusions

These findings do not support the hypothesis that maturation in vitro affects embryo morphokinetics, while they suggest only marginal differences in the morphokinetics of embryos developed from oocytes matured in vivo and in vitro in IVM cycles and embryos developed from mature oocytes recovered in stimulated cycles.
  相似文献   
35.
36.
37.
38.
39.
Early recognition of the signs and symptoms of acute coronary syndromes (ACS) is essential to improving patient management and associated outcomes. It is widely reported that women might have a different ACS symptom presentation than men. Multiple review articles have examined sex differences in symptom presentation of ACS and these studies have yielded inconclusive results and/or inconsistent recommendations. This is largely because these studies have included diverse study populations, different methods of assessing the chief complaint and associated coronary symptoms, relatively small sample sizes of women and men, and lack of adequate adjustment for age or other potentially confounding differences between the sexes. There is a substantial overlap of ACS symptoms that are not mutually exclusive according to sex, and are generally found in women and men. However, there are apparent differences in the frequency and distribution of ACS symptoms among women and men. Women, on average, are also more likely to have a greater number of ACS-related symptoms contributing to the perception that women have more atypical symptoms than men. In this review, we address issues surrounding whether women should have a different ACS symptom presentation message than men, and provide general recommendations from a public policy perspective. In the future, our goal should be to standardize ACS symptom presentation and to elucidate the full range of ACS and myocardial infarction symptoms considering the substantial overlap of symptoms among women and men rather than use conventional terms such as “typical” and “atypical” angina.  相似文献   
40.
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