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   3084篇
  免费   135篇
  国内免费   35篇
耳鼻咽喉   18篇
儿科学   81篇
妇产科学   75篇
基础医学   254篇
口腔科学   64篇
临床医学   212篇
内科学   982篇
皮肤病学   35篇
神经病学   226篇
特种医学   128篇
外科学   590篇
综合类   15篇
一般理论   1篇
预防医学   116篇
眼科学   37篇
药学   146篇
中国医学   1篇
肿瘤学   273篇
  2024年   2篇
  2023年   34篇
  2022年   47篇
  2021年   75篇
  2020年   38篇
  2019年   69篇
  2018年   82篇
  2017年   78篇
  2016年   58篇
  2015年   71篇
  2014年   116篇
  2013年   163篇
  2012年   265篇
  2011年   265篇
  2010年   175篇
  2009年   162篇
  2008年   261篇
  2007年   268篇
  2006年   244篇
  2005年   210篇
  2004年   178篇
  2003年   137篇
  2002年   112篇
  2001年   14篇
  2000年   13篇
  1999年   17篇
  1998年   12篇
  1997年   14篇
  1996年   11篇
  1995年   11篇
  1994年   5篇
  1993年   3篇
  1992年   7篇
  1991年   4篇
  1990年   4篇
  1984年   2篇
  1982年   1篇
  1981年   1篇
  1980年   2篇
  1978年   2篇
  1976年   2篇
  1975年   3篇
  1971年   1篇
  1969年   2篇
  1968年   2篇
  1967年   2篇
  1966年   2篇
  1963年   2篇
  1962年   1篇
  1960年   1篇
排序方式: 共有3254条查询结果,搜索用时 31 毫秒
21.
22.
Although large-scale population studies have shown that non-steroidal anti-inflammatory drugs (NSAIDs) increase the risk of myocardial infarction, this is not confirmed in patients with rheumatoid arthritis (RA). Herein, we review the litterature on the differential effects of NSAIDs on cardiovascular risk in osteoarthritis (OA) versus RA and discuss possible explanations for this discrepancy. To assess a potential additive effect of age in non-RA populations, we compared weighted mean age between RA patients and unselected NSAID users included in cohort and case–control studies that estimate the cardiovascular risk of NSAIDs, assuming that the main indication for NSAID usage in elderly populations is OA. Our hypothesis that advanced age in osteoarthtitis compared to RA patients confounds the effect of NSAIDs on cardiovasular risk was not confirmed. Several other hypotheses that can be proposed to explain this counterintuitive effect of NSAIDs on the cardiovascular risk of RA patients are discussed. We conclude that patients with RA have a lower cardiovascular disease risk associated with the use of NSAIDs, probably due to the nature of their disease per se, until further research indicates differently.  相似文献   
23.
European Journal of Orthopaedic Surgery & Traumatology - In this article, two cases of ulnar nerve neuropathy in Guyon’s canal caused by a ganglion cyst are reported. A review of the...  相似文献   
24.
The majority of vascular access thrombosis episodes in hemodialysis patients are due to anatomic abnormalities. Thrombophilias are inherited, acquired or mixed disorders which also predispose to venous thromboembolism. They include protein C, protein S and antithrombin deficiencies, as well as gene mutations for prothrombin and factor V Leiden. The most important of the mixed cases is hyperhomocysteinemia, which includes both a genetic and an acquired substrate. We report two patients undergoing hemodialysis who suffered from multiple thrombotic events, the first due to factor V Leiden heterozygosity and the second because of hyperhomocysteinemia due to homozygosity for MTHFR C677T mutation. As no site for vascular access was left, transfer to peritoneal dialysis for both patients improved solute clearance and quality of life with no additional thrombotic events noted.  相似文献   
25.
Context/Objective: To investigate prospectively preoperative parameters that might be related to the outcome of surgically treated patients for cervical spondylotic myelopathy (CSM).

Design: Prospective study.

Setting: Single Center in Ioannina, Greece.

Participants: Thirty-six patients were included in the study. There were 21 males and 15 females, mean age 50.8 years, range 39–70 years. The mean BMI was 27.3.

Outcome measures: From each patient, we recorded age, sex, BMI, symptoms, duration of symptoms, comorbidities, lifestyle, myelopathy grade based on MRI and levels of compression. All patients completed the modified JOA (mJOA) and NPE questionnaires preoperatively and at 1, 3, 12 months and 5-years postoperatively.

Results: The mean mJOA score significant improved from 10.8?±?1.9 points preoperatively to 16.6?±?2.2 points at 12 months postoperatively. The mean mJOA score at 5-years postoperatively was 15.5?±?3 points. The difference was still highly significant. The mean NPE score significant improved from 59.8?±?12.2 points preoperatively to 28.2?±?8.5 points at 1 month, to 35.8?±?8.1 points at 3 month and to 28.2?±?8.8 points at 12 months postoperatively. Younger patients had significant higher baseline mJOA scores and significant higher mJOA scores 5-year postoperatively. No correlation was found between sex, BMI, symptom duration, baseline mJOA or myelopathy grade and outcome at 12 months or 5-year postoperatively.

Conclusion: Age was highly predictive factor of outcome for patients undergoing surgical treatment of CSM.  相似文献   
26.
27.
Immediately after the removal of orthodontic appliances, the teeth might start to drift away from their corrected position in an attempt to reach a new equilibrium. Medications and biologic factors could potentially modulate these processes. The objective of the present systematic review is to systematically investigate and appraise the quality of the evidence regarding the effect of various medications and biologic factors on the rate of relapse following active tooth movement. Search without restrictions in eight databases and hand searching until April 2020 were conducted. Studies performed on animal models investigating the effects of medication and biologic factors on the rate of relapse following orthodontic tooth movement were considered. Following study retrieval and selection, relevant data were extracted and the risk of bias was assessed. Seventeen studies were finally identified, mostly at either high or unclear risk of bias. Ketorolac did not show any significant effects on relapse, while the administration of tetracycline, atorvastatin, psoralen and raloxifene decreased it. Overall, the same result was observed with bisphosphonates with the exception of low dosage of risedronate, which did not have an effect. Osteoprotegerin and strontium resulted in reduced relapse, but not in the immediate post-administration period. Inconsistent or conflicting effects were noted after the use of simvastatin and relaxin. The quality of the available evidence was considered at best as low. It can be concluded that specific medications and biologic factors may have an effect on the rate of relapse following tooth movement. The orthodontist should be knowledgeable about the substances potentially affecting retention.  相似文献   
28.
29.
Epigenetic mechanisms participate in melanoma development and progression. The effect of histone modifications and their catalysing enzymes over euchromatic promoter DNA methylation in melanoma remains unclear. This study investigated the potential association of p16INK4A promoter methylation with histone methyltransferase SETDB1 expression in Greek patients with sporadic melanoma and their correlation with clinicopathological characteristics. Promoter methylation was detected by methylation‐specific PCR in 100 peripheral blood samples and 58 melanoma tissues from the same patients. Cell proliferation (Ki‐67 index), p16INK4A and SETDB1 expression were evaluated by immunohistochemistry. High‐frequency promoter methylation (25.86%) was observed in tissue samples and correlated with increased cell proliferation (= 0.0514). p16INK4A promoter methylation was higher in vertical growth‐phase (60%) melanomas than in radial (40%, = 0.063) and those displaying epidermal involvement (= 0.046). Importantly, p16INK4A methylation correlated with increased melanoma thickness according to Breslow index (= 0.0495) and marginally with increased Clark level (I/II vs III/IV/V, = 0.070). Low (1–30%) p16INK4A expression was detected at the majority (19 of 54) of melanoma cases (35.19%), being marginally correlated with tumor lymphocytic infiltration (= 0.078). SETDB1 nuclear immunoreactivity was observed in 47 of 57 (82.46%) cases, whereas 27 of 57 (47.37%) showed cytoplasmic immunoexpression. Cytoplasmic SETDB1 expression correlated with higher frequency of p16INK4A methylation and p16INK4A expression (= 0.033, = 0.011, respectively). Increased nuclear SETDB1 levels were associated with higher mitotic count (0–5/mm2 vs >5/mm2, = 0.0869), advanced Clark level (III‐V, = 0.0380), epidermal involvement (= 0.0331) and the non‐chronic sun exposure‐associated melanoma type (= 0.0664). Our data demonstrate for the first time the association of histone methyltransferase SETDB1 with frequent methylation of the euchromatic p16INK4A promoter and several prognostic parameters in melanomas.  相似文献   
30.
Mesenteric panniculitis (MP) is a rare inflammatory and fibrotic disease of the mesentery of unknown etiology. It has various clinical and radiological manifestations, posing a diagnostic challenge for clinicians. Its diagnosis is indicated via radiologic imaging and is usually confirmed via peritoneal biopsies. We describe a case of a patient with histopathologically proven MP, in which steroid dependence was successfully managed with colchicine.  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