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   2601篇
  免费   199篇
  国内免费   22篇
耳鼻咽喉   20篇
儿科学   39篇
妇产科学   39篇
基础医学   382篇
口腔科学   30篇
临床医学   297篇
内科学   722篇
皮肤病学   57篇
神经病学   298篇
特种医学   29篇
外科学   194篇
综合类   7篇
一般理论   1篇
预防医学   260篇
眼科学   45篇
药学   214篇
中国医学   9篇
肿瘤学   179篇
  2024年   5篇
  2023年   30篇
  2022年   88篇
  2021年   119篇
  2020年   78篇
  2019年   93篇
  2018年   98篇
  2017年   78篇
  2016年   70篇
  2015年   83篇
  2014年   129篇
  2013年   131篇
  2012年   197篇
  2011年   220篇
  2010年   90篇
  2009年   113篇
  2008年   130篇
  2007年   160篇
  2006年   134篇
  2005年   130篇
  2004年   123篇
  2003年   140篇
  2002年   128篇
  2001年   22篇
  2000年   24篇
  1999年   15篇
  1998年   26篇
  1997年   16篇
  1996年   9篇
  1995年   19篇
  1994年   8篇
  1993年   8篇
  1992年   10篇
  1991年   13篇
  1990年   9篇
  1989年   8篇
  1988年   2篇
  1987年   12篇
  1986年   5篇
  1985年   5篇
  1984年   3篇
  1983年   2篇
  1982年   9篇
  1981年   4篇
  1980年   6篇
  1979年   5篇
  1977年   2篇
  1974年   6篇
  1966年   3篇
  1949年   1篇
排序方式: 共有2822条查询结果,搜索用时 15 毫秒
81.
Recent studies suggest an increased risk for Pneumocystis jirovecii pneumonia (PJP) in adults receiving short-interval rituximab-CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) therapy for diffuse large cell B cell lymphoma (DLBCL). This retrospective study evaluates precise PJP incidence and the efficacy of anti-PJP prophylaxis in DLBCL. Patients with DLBCL, aged ≥18 years and treated between December 2004 and December 2010, were included. Details of treatment-related respiratory infections, focusing on PJP incidence, risk factors and prophylaxis, were assessed. A total of 132 patients were analyzed; 47 were treated with rituximab-CHOP therapy every 21 days (R-CHOP-21) and 85 were treated every 14 days (R-CHOP-14). The incidence of treatment-related respiratory infections was higher in patients receiving R-CHOP-14. PJP was diagnosed in 5 patients: 4 in the R-CHOP-14 (6.6%) and 1 in the R-CHOP-21 cohort (2.6%), using triplex polymerase chain reaction (PCR) for PJ in bronchoalveolar fluid. None of the patients receiving P.jirovecii prophylaxis (n = 33) developed PJP, compared with 6.6% of those treated with R-CHOP-14 without such prophylaxis. An older age and R-CHOP administered every 14 rather than every 21 days increased the PJP risk. Trimethoprim/sulfamethoxazole prophylaxis is found to be highly efficient in preventing this life-threatening complication and, therefore, should be recommended for patients receiving the R-CHOP-14 regimen.  相似文献   
82.
Inflammatory bowel disease is accompanied by extraintestinal manifestations in a high percentage of patients. Cutaneous lesions are the second most prevalent of these manifestations, and within these, metastatic Crohn's disease is one of the least common, being the least frequent specific cutaneous manifestation of Crohn's disease. This entity includes cutaneous and subcutaneous lesions with a non-caseating granulomatous appearance on histological analysis identical to that of Crohn's disease. These lesions are not found adjacent to the digestive tract. Due to the low prevalence of these manifestations, conclusive trials on the treatment of choice have not been performed and there is no well-defined therapeutic strategy. Distinct therapies with varying results have been reported. We report the case of a female patient with longstanding and complex Crohn's disease who developed metastatic cutaneous manifestations while receiving adalimumab. The cutaneous manifestations responded well to dose intensification of this drug. A review of the literature is provided.  相似文献   
83.
MicroRNAs (miRNAs) are small non-coding RNA molecules that negatively regulate gene expression. They actively participate in the modulation of important cell physiological processes and are involved in the pathogenesis of lung diseases such as lung cancer, pulmonary fibrosis, asthma and chronic obstructive pulmonary disease. A better understanding of the role that miRNAs play in these diseases could lead to the development of new diagnostic and therapeutic tools. In this review, we discuss the role of some miRNAs in different lung diseases as well as the possible future of these discoveries in clinical applications.  相似文献   
84.
85.

Objective

This study aimed to evaluate the effects of heat treatment on the tribochemical silica coating and silane surface conditioning and the bond strength of rebonded alumina monocrystalline brackets.

Material and Methods

Sixty alumina monocrystalline brackets were randomly divided according to adhesive base surface treatments (n=20): Gc, no treatment (control); Gt, tribochemical silica coating + silane application; Gh, as per Gt + post-heat treatment (air flux at 100ºC for 60 s). Brackets were bonded to the enamel premolars surface with a light-polymerized resin and stored in distilled water at 37ºC for 100 days. Additionally, half the specimens of each group were thermocycled (6,000 cycles between 5-55ºC) (TC). The specimens were submitted to the shear bond strength (SBS) test using a universal testing machine (1 mm/min). Failure mode was assessed using optical and scanning electron microscopy (SEM), together with the surface roughness (Ra) of the resin cement in the bracket using interference microscopy (IM). 2-way ANOVA and the Tukey test were used to compare the data (p>0.05).

Results

The strategies used to treat the bracket surface had an effect on the SBS results (p=0.0), but thermocycling did not (p=0.6974). Considering the SBS results (MPa), Gh-TC and Gc showed the highest values (27.59±6.4 and 27.18±2.9) and Gt-TC showed the lowest (8.45±6.7). For the Ra parameter, ANOVA revealed that the aging method had an effect (p=0.0157) but the surface treatments did not (p=0.458). For the thermocycled and non-thermocycled groups, Ra (µm) was 0.69±0.16 and 1.12±0.52, respectively. The most frequent failure mode exhibited was mixed failure involving the enamel-resin-bracket interfaces.

Conclusion

Regardless of the aging method, Gh promoted similar SBS results to Gc, suggesting that rebonded ceramic brackets are a more effective strategy.  相似文献   
86.
The objective of this study was to investigate the effects of low-level laser therapy (LLLT) treatment alone (λ?=?660 nm and λ?=?830 nm) or associated with platelet-rich plasma (PRP). We used 54 male rats divided into six groups, with nine animals each: group 1, partial tenotomy; group 2 (GII), PRP; group 3 (GIII): λ660?nm; group 4 (GIV), λ830?nm; group 5 (GV), PRP + λ660?nm; and group 6 (GVI), PRP + λ830?nm. The protocol used was power density 0.35 W/cm2, energy 0.2 J, energy density 7.0 J/cm2, time 20 s per irradiated point, and number of points 3. Animals in groups GII, GV, and GVI received treatment with PRP, consisting of a single dose of 0.2 mL directly into the surgical site, on top of the tenotomy. Animals were killed on the 13th day post-tenotomy and their tendons were surgically removed for a quantitative analysis using polarization microscopy. The percentages of collagen fibers of types I and III were expressed as mean ± SD. Higher values of collagen fibers type I were obtained for groups GV and GVI when compared with all other groups (p?<?0.05), whereas groups GIII and GIV showed no significant difference between them (p?>?0.05). For collagen type III, a significant difference was observed between GII and all other groups (p?<?0.5), but no significant difference was found between GIII and GIV and between GV and GVI. Results showed that the deposition of collagen type I was higher when treatment with PRP and LLLT was combined, suggesting a faster regeneration of the tendon.  相似文献   
87.
ObjectiveDiabetic nephropathy is a common cause of end stage renal disease. Notwithstanding, wide inter-individual variations in the speed of progression of diabetic nephropathy are frequent. We have used the score of the HUGE formula to predict progression of kidney disease in a group of diabetic nephropathy patients.Design and methodsThe sample consisted of 84 type 2 diabetic patients. At treatment entry, the mean age was 62.1 ± 12.5 years and 59.5% were male. Blood pressure was measured at office at each visit. Serum creatinine, urea, hematocrit and 24 h proteinuria were analyzed every 6 months. HUGE score was calculated from gender, urea and hematocrit.ResultsMean HUGE score was 0.99 ± 3.88. Using as cut off point 1.5, those patients who had a score equal or higher (n = 31) showed a bigger increase in serum creatinine after one year (41.8 ± 62.1%) than those subjects with score < 1.5 (n = 53) (18.7 ± 38.6%, p = 0.041). 5 patients with low HUGE score reached end stage renal failure (9.4%) and 10 patients in the high HUGE score group (32.3, p = 0.008). When logistic regression analysis was performed only a HUGE score higher than 1.5 (p = 0.003) and proteinuria higher than 2 g/day (p = 0.041) were independently associated to CRF progression (creatinine increment > 25%).ConclusionsIn diabetic nephropathy patients the HUGE equation may be useful to detect the subjects prone to progressive renal failure. Wider samples will be needed to confirm this finding and, most important, its applicability to other kinds of nephropathy.  相似文献   
88.

Background  

Excess endogenous steroids are a risk factor for obstructive sleep apnea (OSA). The role of exogenous steroids in this setup is not known. In this study, we prospectively looked at the consequences of a 3-month steroid treatment on the objective measures of sleep-disordered breathing.  相似文献   
89.
The evaluation of cognitive status is not routine in the acute stroke setting. We aimed to investigate feasibility, applicability, and performances of the Montreal cognitive assessment (MoCA) in acute stroke patients. Consecutive stroke patients (ischemic or hemorrhagic) admitted to one stroke unit were evaluated 5–9 days after stroke with MoCA (score range: 0–30; higher scores indicate better cognitive performance). Pre-morbid functional and cognitive status was assessed by a structured interview to caregivers. Neuroimaging data regarding index stroke and pre-existing lesions were collected. From December 2009 to December 2010, out of 207 patients with stroke, 137 (66 %) were enrolled [mean age 69.2 ± 14.8 years; males 62 %; mean National Institute of Health and Stroke Scale (NIHSS) score 5.9 ± 7.9]. The most common reason for non-enrolment was unfitting the time window inclusion criteria. MoCA was entirely applicable to 113/137 (82.5 %) patients and the mean score was 17.8 ± 7.1. Multivariate analyses showed that non-applicability was associated with higher NIHSS scores [OR (95 % CI) = 1.4 (1.2–1.7) for each point], left sided lesions [OR (95 % CI) = 18.8 (2.3–155.2)], and worse pre-morbid functional status [OR (95 % CI) = 0.7 (0.6–0.9) for each point of the instrumental activity of daily living scale]. Factors influencing MoCA performance were low education (β = 0.264, p < 0.01), higher NIHSS scores (β = ?0.277, p < 0.01) and worse pre-morbid functional status (β = 0.504, p < 0.001). MoCA administration is feasible in acute patients with mild-to-moderate stroke, with lesion location, stroke severity, and pre-morbid functional status as major determinants of its applicability and performance. MoCA seems to reveal some degree of cognitive deficit even in patients with mild stroke.  相似文献   
90.
Journal of Neurology - TK2 deficiency (TK2d) is a rare mitochondrial disorder that manifests predominantly as a progressive myopathy with a broad spectrum of severity and age of onset. The rate of...  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