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   345篇
  免费   9篇
  国内免费   4篇
耳鼻咽喉   2篇
儿科学   9篇
妇产科学   1篇
基础医学   29篇
口腔科学   42篇
临床医学   25篇
内科学   40篇
神经病学   14篇
特种医学   17篇
外科学   131篇
综合类   15篇
预防医学   6篇
眼科学   5篇
药学   9篇
肿瘤学   13篇
  2018年   4篇
  2015年   9篇
  2014年   11篇
  2013年   24篇
  2012年   20篇
  2011年   12篇
  2010年   15篇
  2009年   6篇
  2008年   11篇
  2007年   3篇
  2006年   6篇
  2005年   4篇
  2004年   5篇
  2003年   3篇
  2002年   5篇
  2000年   2篇
  1999年   6篇
  1998年   4篇
  1997年   11篇
  1996年   4篇
  1995年   8篇
  1994年   3篇
  1993年   4篇
  1992年   6篇
  1991年   4篇
  1990年   8篇
  1989年   7篇
  1988年   3篇
  1987年   4篇
  1986年   7篇
  1985年   4篇
  1984年   4篇
  1983年   3篇
  1982年   2篇
  1981年   3篇
  1979年   2篇
  1978年   5篇
  1977年   11篇
  1976年   13篇
  1975年   13篇
  1974年   10篇
  1973年   11篇
  1972年   13篇
  1971年   8篇
  1970年   11篇
  1969年   4篇
  1967年   3篇
  1966年   3篇
  1965年   4篇
  1964年   3篇
排序方式: 共有358条查询结果,搜索用时 15 毫秒
101.

Background

Stool-based molecular tests hold large potential for improving colorectal cancer screening. Here, we investigated the analytical sensitivity of a DNA methylation assay on partial stool samples, and estimated the DNA degradation in stool over time. In addition, we explored the detection of DNA methylation in fecal immunochemical test (FIT) fluid.

Materials and Methods

Partial stool samples of colonoscopy-negative individuals were homogenized with stool homogenization buffer, spiked with different numbers of HCT116 colon cancer cells and kept at room temperature for 0, 24, 48, 72 and 144?h before DNA isolation. Analytical sensitivity was determined by the lowest number of cells that yielded positive test results by DNA methylation or mutation analysis. DNA methylation in FIT fluid was measured in 11 CRC patients and 20 control subjects.

Results

The analytical sensitivity for detecting DNA methylation was 3000 cells per gram stool, compared to 60000 cells per gram stool for detection of DNA mutations in the same stool samples. No degradation up to 72?h was noted when a conservation buffer was used. DNA methylation was detected in 4/11 CRC FIT samples and in none of the 20 control FIT samples.

Conclusions

Methylation based stool DNA testing showed a high analytical sensitivity for tumor DNA in partial stool samples, which was hardly influenced by DNA degradation over time, provided an adequate buffer was used. The feasibility of detecting DNA methylation in FIT fluid demonstrates the opportunity to combine testing for occult blood with DNA methylation in the same collection device.  相似文献   
102.

Background

Spontaneous uterine rupture is a life threatening obstetrical emergency encountered infrequently in the emergency department. Its diagnosis is often missed or delayed, leading to maternal and fetal mortality.

Method

We present a case of ruptured uterus diagnosed by ultrasound in a 33-year-old gravid female with two previous cesarean sections.

Objective

To show the role of ultrasound in uterine rupture

Result

Ultrasound demonstrates uterine laceration and intra-abdominal dislocation of placenta and foetus

Conclusion

Because of the severity of the complication and the great variation of symptoms in connection with it, the authors encourage the use of ultrasound screening in the detection of this rare, but often catastrophic complication.  相似文献   
103.
104.
Pain due to cancer is frequently visceral, and neurolysis of the sympathetic axis has been shown to be an effective and safe method for treating this visceral pain. Several studies have documented the efficacy of neurolytic blocks both by a reduction in the intensity of pain and by a decrease in opioid consumption. Neurolysis of the sympathetic axis should be incorporated into the pain specialist's arsenal as an adjuvant to oral pharmacologic therapy.  相似文献   
105.
OBJECTIVE: Viscosupplementation with hylan G-F 20 has recently become registered for treatment of patients with osteoarthritis (OA) of the knee in most parts of the world. The cost effectiveness and cost utility of this new therapeutic modality were determined as part of a Canadian prospective, randomized, 1-year, open-label, multicentered trial. DESIGN: A total of 255 patients were randomized to 'Appropriate care with hylan G-F 20' (AC+H) or 'Appropriate care without hylan G-F 20' (AC). Costs (1999 Canadian dollars) were collected from the societal viewpoint and included all costs related to OA of the knee and OA in all joints. Patients completed a number of outcomes questionnaires including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Health Utilities Index Mark 3 (HUI3). Data were collected at clinic visits (baseline, 12 months) and by telephone (1, 2, 4, 6, 8, 10, and 12 months). RESULTS: The AC+H group over the year had higher costs ($2125-$1415=$710, P< 0.05), more patients improved (69%-40%=29%,P =0.0001), greater increases in HUI3 (0.13-0.03=0.10, P< 0.0001) and increased quality-adjusted life years (QALYs) (0.071, P< 0.05). The incremental cost-effectiveness ratio was $2505/patient improved. The incremental cost-utility ratio was $10000/QALY gained. Sensitivity analyses and a second cost perspective gave similar results. CONCLUSION: The cost-utility ratio is below the suggested Canadian adoption threshold. The results provide strong evidence for adoption of treatment with hylan G-F 20 in the patients and settings studied in the trial.  相似文献   
106.
As the highly active antiretroviral therapy (HAART) has transitioned human immunodeficiency virus (HIV) infection into a 'chronic disease' management strategy, there is growing evidence that infection with non-HIV pathogens in HIV+ patients may have important public health implications in undermining HAART success and acquired immunodeficiency syndrome progression. Several bacterial and host cell products during infections with non-HIV pathogens have shown the capacity to regulate HIV replication in latently infected cells. A high prevalence of oral infections caused by bacteria, viruses and fungi has been described in HIV+ patients, including periodontal disease. The oral cavity appears to be a site of HIV pathogenesis and potential reservoir for the disease as HIV RNA and DNA forms are present in saliva as well as in gingival crevicular fluid, and oral epithelial cells are susceptible to either cell free or cell-associated HIV infection. The clinical and biological bases of potential associations between chronic oral inflammatory disorders, such as periodontal disease, and exacerbation of HIV viraemia have received little attention. This review attempts to evaluate the current understanding of HIV reactivation as a result of co-infection and/or inflammation induced by non-HIV pathogens in HIV-infected patients, and presents a hypothetic model about the potential role of periodontitis as a global oral infection that potentially contributes to HIV recrudescence.  相似文献   
107.

Objective

Awareness of stimuli originating inside of the body (interoceptive awareness) is thought to have an impact on psychopathology. The aim of the present study was to analyze whether heartbeat perception accuracy is reduced in depressed patients. Furthermore, we investigated whether putative differences are reflected in heartbeat-evoked potentials.

Method

We assessed the heartbeat perception score in 16 depressed patients and in matched healthy controls. A 63-channel EEG was recorded while participants counted pseudo-randomly presented target tones or heartbeats during a fixed number of cardiac cycles. ECG R-waves served as the trigger for EEG averaging. The cardiac-field artifact was minimized using independent component analysis and current–source density.

Results

Behaviorally, the depressed sample showed less accurate heartbeat perception in comparison to the control group (p = .011). The two groups also demonstrated psychophysiological differences, showing that heartbeat-evoked potentials were significantly reduced in depressed patients.

Conclusions

Our results suggest that heartbeat evoked potentials are objective markers of altered bodily awareness. Reduced interoception during depression may be linked to alexithymia, as well as to both decreased capacity for decision-making and for cognitive processing.

Significance

It may be helpful to practice interoceptive awareness to improve depressive symptoms, for example by practicing meditation.  相似文献   
108.
Summary A multiplicity of surgical operations have been developed in an attempt to achieve satisfactory function after anterior cruciate ligament (ACL) repair. None of these procedures have been able to reproduce the fiber organization anatomy of attachment site, vascularity, or function of the ACL. Twenty-nine foxhounds received a deep-frozen bone-ACL-bone allograft and a ligament augmentation device (LAD). Biomechanical, microvascular, and histological changes were evaluated 3, 6, and 12 months following implantation. The maximum loads of the allograft/LADs were 34.3% (387.2N) after 3 months, 49.3% (556.6N) after 6 months, and 61.1% (698.8N) after a year. The maximum load was 69.1% (780 N). In general, after 6 months the allografts showed normal collagen orientation. The allografts demonstrated no evidence of infection or immune reaction. No bone ingrowth into the LAD was observed. Polarized light microscopy and periodic acid-schiff staining showed that the new bone-ligament substance interface had intact fiber orientation at the area of the ligament insertion. Microvascular examination using the Spalteholtz technique revealed revascularization and the importance of an infrapatellar fat pad for the nourishment of ACL allografts.  相似文献   
109.
110.
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