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   1994篇
  免费   94篇
  国内免费   35篇
耳鼻咽喉   18篇
儿科学   138篇
妇产科学   23篇
基础医学   313篇
口腔科学   48篇
临床医学   168篇
内科学   344篇
皮肤病学   74篇
神经病学   136篇
特种医学   246篇
外科学   174篇
综合类   44篇
预防医学   79篇
眼科学   132篇
药学   81篇
中国医学   3篇
肿瘤学   102篇
  2022年   28篇
  2021年   45篇
  2020年   31篇
  2019年   32篇
  2018年   59篇
  2017年   36篇
  2016年   33篇
  2015年   50篇
  2014年   51篇
  2013年   83篇
  2012年   90篇
  2011年   92篇
  2010年   91篇
  2009年   79篇
  2008年   83篇
  2007年   97篇
  2006年   82篇
  2005年   73篇
  2004年   58篇
  2003年   56篇
  2002年   33篇
  2001年   38篇
  2000年   49篇
  1999年   48篇
  1998年   56篇
  1997年   52篇
  1996年   55篇
  1995年   36篇
  1994年   44篇
  1993年   42篇
  1992年   25篇
  1991年   32篇
  1990年   19篇
  1989年   36篇
  1988年   57篇
  1987年   42篇
  1986年   27篇
  1985年   38篇
  1984年   7篇
  1983年   7篇
  1982年   10篇
  1981年   9篇
  1980年   11篇
  1979年   13篇
  1977年   8篇
  1976年   13篇
  1975年   6篇
  1973年   8篇
  1972年   12篇
  1971年   12篇
排序方式: 共有2123条查询结果,搜索用时 15 毫秒
61.
Background: Q-switched lasers are conventionally used for the treatment of black tattoo. However, they require multiple sittings, and the response may be slow due to competing epidermal pigment in dark skin. Objective: To compare the efficacy of Q-switched Nd:YAG laser alone with its combination with ultrapulse CO2 for the removal of black tattoo. Materials and methods: Sixty patients with black tattoo were randomized into two groups viz., group A and group B. Group A was treated with QS Nd:YAG laser (1064 nm) alone, and group B received combination of ablative ultrapulse CO2 followed by fixed-dose QS Nd:YAG laser (1064 nm), at 6-week interval for a maximum of 6 sittings. After each sitting, 3 independent physicians noted percentage of improvement that was evaluated using visual analogue scale (VAS) and grading system for tattoo ink lightening (TIL). Results: Combination laser (group B) showed statistically significant improvement in mean VAS score in the last 2 noted visits as compared to 1st session (p < 0.007, p < 0.001) and TIL mean score in last three noted visits as compared to 1st session (p < 0.008, p < 0.020, and p < 0.004). There was no statistically significant difference in the side effect profile of both the groups. Conclusion: For refractory professional tattoos, combination of ultrapulse CO2 laser and QS Nd:YAG laser is superior to QS Nd:YAG laser alone.  相似文献   
62.
BACKGROUND: Bone, soft-tissue, and articular lesions are often well visualized by magnetic resonance imaging. Our goal was to evaluate the diagnostic performance of magnetic resonance imaging-guided biopsies of selected musculoskeletal lesions. METHODS: In this retrospective case series, forty-five consecutive biopsies were performed in an open mid-field 0.5-T interventional magnetic resonance imaging unit with a real-time guidance system. The biopsies were performed at twenty bone, eighteen extra-articular soft-tissue, and seven intra-articular soft-tissue sites. The main reasons for using magnetic resonance imaging guidance were the need to improve lesion conspicuity compared with that provided by other imaging modalities, the need for site-specific targeting within the lesion, and the need for real-time guidance. Samples were obtained with fine-needle aspiration, core-needle biopsy, or a combination of these techniques. An independent reference standard was used to confirm the final diagnosis. Diagnostic performance was evaluated on the basis of the diagnostic yield (the proportion of biopsies yielding sufficient material for pathological evaluation) and diagnostic accuracy (sensitivity, specificity, positive predictive value, and negative predictive value). Complications were identified as well. RESULTS: The diagnostic yield was 91% (forty-one of forty-five biopsies yielded sufficient material for a diagnosis) overall, 95% (nineteen of twenty) for the bone lesions, 94% (seventeen of eighteen) for the extra-articular soft-tissue lesions, and 71% (five of seven) for the intra-articular soft-tissue lesions. With regard to the diagnostic accuracy, the sensitivity was 0.86, the specificity was 1.00, the positive predictive value was 1.00, and the negative predictive value was 0.76 in the overall group. The respective values were 0.92, 1.00, 1.00, and 0.86 for the bone lesions; 0.77, 1.00, 1.00, and 0.57 for the extra-articular soft-tissue lesions; and 1.00, 1.00, 1.00, and 1.00 for the intra-articular soft-tissue lesions. There was one complication: exacerbation of neuropathic pain related to a biopsy of a peripheral nerve sheath tumor. CONCLUSIONS: Magnetic resonance imaging-guided percutaneous biopsies of musculoskeletal lesions for which other imaging modalities might be inadequate have a good diagnostic performance overall. The performance can be very good for bone lesions, moderate for extra-articular soft-tissue lesions, and fair for intra-articular soft-tissue lesions.  相似文献   
63.
64.
65.
66.
67.
Fibrillary renal deposits and nephritis.   总被引:3,自引:1,他引:3  
Fibrillary renal deposits and nephritis. The authors have studied 8 patients whose glomeruli contain abundant fibrils in their mesangial matrix and basement membranes. Although the location of these fibrils is very similar to that of amyloid, they are about twice the size of amyloid fibrils, averaging 20 nm in width, and fail to react as amyloid does with special stains. Immunofluorescence-microscopic studies are usually positive with antiserums to IgG, often IgM, and in some cases IgA, and also kappa and lambda light chains, C3, and C4. The fibrils are associated with diffuse mesangial widening and increased mesangial matrix strands. Although peripheral glomerular capillary walls appear to be spared initially, their eventual involvement leads to glomerular capillary collapse and glomerular obsolescence. Crescent formation occurred in 5 cases, focally in 3 and diffusely in 2. Tubular basement membrane involvement was seen in 1 case. These patients exhibit hematuria, and proteinuria, and often hypertension and renal insufficiency. Proteinuria was in the nephrotic range in 3 patients in whom involvement of glomerular capillary basement membranes was extensive. Unless electron microscopy is applied to renal biopsies, these cases may be considered to represent mesangiocapillary or rapidly progressive glomerulonephritis, or amyloidosis. The nature of these fibrils is as yet not determined. It is likely that they have been called "atypical amyloidosis" in the past.  相似文献   
68.
Ocular compression (OC) is a maneuver performed during EEG to demonstrate increased vagal reactivity in children with suspected syncope including breath-holding spells. We examined the relationship between the simulated OC pressure exerted by different physicians and the cardiac slowing responses that they had historically obtained as per EEG records. Simulated OC was performed by each physician using a sphygmomanometer. EEGs were reviewed for the rate of positive cardiac slowing per physician. Among three physicians who performed a total of 73 OC, the mean +/- SD of applied pressure were 29.0 +/- 2.4, 60.7 +/- 3.5 and 42.4 +/- 2.5 mmHg, respectively. There was good intra-physician consistency for the OC pressures exerted. The mean pressure exerted was significantly different between physicians (p < 0.001, ANOVA). The positive response rate for cardiac slowing among these physicians was 11/37 (29.7%), 10/21 (47.6%) and 8/15 (53.3%) respectively. The difference in positive OC responses between physicians was not significant (p = 0.127, chi-square). Higher OC pressures did not translate into more positive responses. A pressure of 30 mmHg is as good as 60 mmHg in demonstrating cardiac slowing during OC.  相似文献   
69.
Background Heart failure (HF) is a physically and socially debilitating disease that carries the burden of hospital re-admission and mortality. As an aging society, Hong Kong urgently needs to find ways to reduce the hospital readmission of HF patients. This study evaluates the effects of a nurse-led HF clinic on the hospital readmission and mortality rates among older HF patients in Hong Kong. Methods This study is a retrospective data analysis that compares HF patient in a nurse-led HF clinic in Hong Kong compared with HF patients who did not attend the clinic. The nurses of this clinic provide education on lifestyle modification and symptom monitoring, as well as titrate the medications and measure biochemical markers by following established protocols. This analysis used the socio-demographic and clinical data of HF patients who were aged ≥ 65 years old and stayed in the clinic over a six-month period. Results The data of a total of 78 HF patients were included in this data analysis. The mean age of the patients was 77.38 ± 6.80 years. Approximately half of the HF patients were male (51.3%), almost half were smokers (46.2%), and the majority received ≤ six years of formal education. Most of the HF patients (87.2%) belonged to classes II and III of the New York Heart Association Functional Classification, with a mean ejection fraction of 47.15 ± 20.31 mL. The HF patients who attended the clinic (n = 38, 75.13 ± 5.89 yrs) were significantly younger than those who did not attend the clinic (n = 40, 79.53 ± 6.96 yrs) (P = 0.04), and had lower recorded blood pressure. No other statistically significant difference existed between the socio-demographic and clinical characteristics of the two groups. The HF patients who did not attend the nurse-led HF clinic demonstrated a significantly higher risk of hospital readmission [odd ratio (OR): 7.40; P < 0.01] than those who attended after adjusting for the effect of age and blood pressure. In addition, HF patients who attended the clinic had lower mortality (n = 4) than those who did not attend (n = 14). However, such a difference did not reach statistical significance when the effects of age and blood pressure were adjusted. A significant reduction in systolic blood pressure [F (2, 94) = 3.39, P = 0.04] and diastolic blood pressure [F (2, 94) = 8.48, P < 0.01] was observed among the HF patients who attended the clinic during the six-month period. Conclusions The finding of this study suggests the important role of nurse-led HF clinics in reducing healthcare burden and improving patient outcomes among HF patients in Hong Kong.  相似文献   
70.
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