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   2853篇
  免费   84篇
  国内免费   33篇
耳鼻咽喉   5篇
儿科学   32篇
妇产科学   27篇
基础医学   410篇
口腔科学   56篇
临床医学   124篇
内科学   883篇
皮肤病学   27篇
神经病学   239篇
特种医学   144篇
外科学   376篇
综合类   8篇
预防医学   77篇
眼科学   35篇
药学   157篇
中国医学   8篇
肿瘤学   362篇
  2022年   14篇
  2021年   25篇
  2020年   23篇
  2019年   33篇
  2018年   32篇
  2017年   27篇
  2016年   43篇
  2015年   49篇
  2014年   77篇
  2013年   81篇
  2012年   145篇
  2011年   184篇
  2010年   96篇
  2009年   92篇
  2008年   152篇
  2007年   178篇
  2006年   180篇
  2005年   210篇
  2004年   189篇
  2003年   187篇
  2002年   188篇
  2001年   40篇
  2000年   26篇
  1999年   40篇
  1998年   46篇
  1997年   47篇
  1996年   40篇
  1995年   36篇
  1994年   27篇
  1993年   37篇
  1992年   32篇
  1991年   24篇
  1990年   29篇
  1989年   27篇
  1988年   20篇
  1987年   23篇
  1986年   19篇
  1985年   11篇
  1984年   21篇
  1983年   14篇
  1981年   13篇
  1980年   14篇
  1979年   17篇
  1978年   15篇
  1977年   15篇
  1976年   12篇
  1975年   13篇
  1972年   15篇
  1970年   14篇
  1969年   15篇
排序方式: 共有2970条查询结果,搜索用时 31 毫秒
1.
2.
3.
The aim of this study was to evaluate whether the lesion regression rate (ΔLR) based on the Response Evaluation Criteria in Solid Tumors (RECIST) criteria could be used for the prediction of treatment outcome in head and neck squamous cell carcinoma (HNSCC) patients treated with chemoradiotherapy (CRT) compared with FDG PET-CT. A total of 33 patients underwent MRI and PET-CT at pretreatment and at 8 weeks after CRT. We assessed the treatment outcome by analyzing the following parameters: the RECIST criteria, ΔLR, the European Organization for Research and Treatment of Cancer (EORTC) criteria, and pretreatment SUVmax of the primary tumor and node. The correlation between the analysis of the parameters and the results of the long-term follow-up of the patients was determined. The RECIST did not significantly correlate with locoregional control (LRC) or survival. The ΔLR was significantly lower for the lesions with locoregional failure (LRF) than for those with LRC. A threshold ΔLR of 48% revealed a sensitivity of 72.7% and specificity of 77.3% for the prediction of LRF. Progression-free survival (PFS) of patients with ΔLR ≥ 48% was significantly better than that of patients with ΔLR < 48% (P = 0.001), but not overall survival. There was a significant correlation between LRC and the EORTC (P = 0.02). The patients who achieved a complete response by the EORTC criteria showed significantly better PFS and overall survival (P = 0.01 and 0.04, respectively). The ΔLR was inferior to FDG PET-CT with respect to the prediction of patient survival; however, it may be useful for selecting patients in need of more aggressive monitoring after CRT.  相似文献   
4.
BACKGROUND: In patients with chronic kidney disease (CKD), although strong associations have been observed between malnutrition and atherosclerosis, the relationship between serum albumin concentration and angiographic changes of coronary artery disease (CAD) remains poorly explored. The goal of the present study was, in patients with CKD, to clarify the relationship between the angiographic severity of CAD and serum albumin concentration reflecting either inflammation or nutrition or both. METHODS: In this study, 100 end-stage renal disease (ESRD) patients were enrolled, who commenced long-term dialysis therapy at our hospital and underwent coronary angiography within 3 months of the first haemodialysis (HD) session. Mean age was 63+/-11 years, 20% of the subjects were female and 62% had diabetes. Severity of CAD was evaluated in terms of (i) number of vessels exhibiting CAD (>or=75% stenosis) and (ii) Gensini score (GS). Clinical characteristics and laboratory findings were recorded at initiation of long-term HD therapy. We then evaluated a possible association with the presence and degree of CAD. RESULTS: Sixty-four patients exhibited signs of CAD. Forty-one among them (64%) had multivessel disease. On univariate logistic regression analysis, age, diabetes and hypoalbuminaemia were significantly associated with multivessel CAD. Univariate linear regression analysis demonstrated a positive correlation of age and diabetes with GS, and an inverse correlation of BMI and serum albumin level with GS. Stepwise regression analysis showed age and serum albumin level to be independently associated with multivessel CAD and GS. The ROC curves demonstrated best cut-off levels of age and albumin for predicting multivessel CAD to be 70 years and 3.15 g/dl, respectively. CONCLUSION: Hypoalbuminaemia at the initiation of dialysis is an important predictor of advanced CAD, particularly in male and in diabetic patients. It may reflect mainly a state of inflammation. However, malnutrition as a confounding factor cannot be entirely excluded.  相似文献   
5.
Background: Buried bumper syndrome (BBS) is a rare complication of percutaneous endoscopic gastrostomy (PEG). Along with the widespread use of the button‐type kit, BBS is encountered frequently. Methods: In the present study, we examined causes and treatments for BBS among 1400 patients who had undergone PEG. Results: The causes of BBS after PEG were classified into two categories: early causes consisted of wound infection, inappropriate size of kit and severe lordosis, while late causes were inappropriate exchange of kit, rough management or weight gain. The treatments for BBS could be determined by the degree of wound infection, fistula and burial of the bumper. Conclusion: We prepared a flowchart for replacement, by which BBS can be managed safely and quickly without surgical or endoscopic intervention.  相似文献   
6.
One hundred and thirty-four patients with vasoocclusive diseases were retrospectively tested for three kinds of antiphospholipid antibody (aPL). The mean age at onset of the disease in 58 patients with aPL was 43 years old. Seventeen, 11, and 9 patients were positive for the aCL IgA, IgM, and IgG isotypes, respectively. The rates of anti-phospholipid syndrome (APS) in patients with arterial (n=94), venous (n= 31), or both arterial and venous (n=9) occlusion were 45%, 29%, and 78%, respectively.The rates of APS in patients with autoimmune disease (n=13), thromboangiitis obliterans (TAO) (n= 36), arteriosclerosis obliterans (ASO) with lower leg involvement (n=8) or aortic arch syndrome (n=5), Raynaud's syndrome (n=15), aortitis syndrome (n= 13), ischemic heart disease (IHD) with young onset (n =12), and bilateral leg deep venous thrombosis (DVT) (n=10) were 77%, 46%, 13%, 80%, 40%, 62%, 33%, and 70%, respectively. The cumulative patency rate for reconstructive surgery in patients (n=13) with aCL was found to be considerably lower than that in those without aCL (n=13). From these results it was concluded that IgA was the most valuable aCL isotype for the diagnosis of APS and that aPL should be examined in patients with double-vessel occlusion, autoimmune disease, bilateral leg DVT, aortic arch syndrome, TAO, Raynaud's syndrome, or IHD with young onset. Furthermore, prophylaxis for graft failure is more strongly recommended for patients with aCL than for those without it.  相似文献   
7.
1. We previously reported that volatile anaesthetics produce incidences of a transient opisthotonus in mice, a sign of CNS stimulation. This study was performed to investigate mechanisms by which enflurane-induced opisthotonus (EIO) occurs. 2. The effects of pretreatment of N-methyl-d-aspartate (NMDA) antagonists dizocilpine (MK-801; DIZ) and ketamine (KET), GABAA antagonists picrotoxin (PIC), pentylenetetrazol (PTZ) and glycine antagonist strychnine (STR) on the incidence of EIO were determined. Prior to exposure to 2.0% enflurane in air, male ddN mice were given intraperitoneal injections of 0.2 mL saline (control), 0.5–5.0 mg/kg DIZ, 20–80 mg/kg KET, 2.9 mg/kg PIC, 40.0 mg/kg PTZ and 0.75 mg/kg STR. After the injection, the behavioural state of the mice was observed for 20 min (the pre-enflurane period). During the exposure to enflurane the time for immobilization, that is, anaesthetic induction time (IT), and the incidence of EIO were measured. 3. Dizocilpine (1.0–5.0 mg/kg) and KET (80 mg/kg) significantly (P<0.01) reduced both the incidence of EIO and IT in a dose-dependent manner. During the pre-enflurane period DIZ produced incidences (5–40%) of transient seizures in a dose-dependent manner, while KET did not induce them at all. The two GABAa antagonists had no detectable effect on the EIO. Strychnine significantly enhanced the EIO. These CNS stimulants resulted in a 3–10% incidence of transient seizure and/or opisthotonus during the pre-enflurane period, but there was no correlation between DIZ-induced seizure and EIO. 4. These results suggest that the EIO is mediated by the NMDA and the STR-sensitive glycine receptors, but not the GABAA receptor. We speculate that DIZ acts on the NMDA-receptor and/or disrupts the balance between the inhibitory and the excitatory systems.  相似文献   
8.
Practical guidelines for physicians in the management of febrile seizures   总被引:14,自引:0,他引:14  
Recent studies have shown that adequate medication can prevent the recurrence of febrile seizures (FS). It has also been clarified that the vast majority of, though not all, FS patients follow a benign course. Then, questions arise as to whether or not FS should be prevented, particularly in light of the risks of side effects from drugs. Which kinds of FS can be prevented, if necessary? The guidelines presented here are aimed primarily at helping general practitioners in considering how to manage FS most appropriately. The guidelines stress that judgements should be individualized, while referring to a few specific ‘warning factors’. The guidelines follow a ‘laissez-faire’ principle for the majority of FS cases, whereas intermittent therapy with diazepam and continuous medication with either phenobarbital or valproate are indicated in other limited cases meeting respective definite criteria.  相似文献   
9.
The relationship between the histological grade of dedifferentiation of thyroid cancer and estrogen receptors (ER) was examined immunohistochemically. Thyroid cancers were from postmenopausal females of almost the same mean age (69-73 years old) and within the same period of time (1974–1983). ER immunoreactivity located in the nucleus of the epithelium was found in all 6 well differentiated papillary cancers, and 5 of them (83.3%) showed ER-immunoreactive (ER-IR) cells amounting to 20 or more per visual field (x 100) under a light microscope. Of the 6 cases of poorly differentiated papillary cancer, 5 (83.3%) had 1-19 ER-IR cells per visual field. ER-IR cells were negative in 5 out of 6 cases (83.3%) of anaplastic cancers. Thus, the number of ER-IR cells tended to decrease with the degree of atypism of thyroid cancer (P < 0.001).  相似文献   
10.
Biodegradable copolymers of L -lactic acid (L -LA) and DL -α-hydroxy acids with relatively low molecular weights, for example L -LA/DL -lactic acid (DL -LA), L -LA/DL -α-hydroxybutyric acid (DL -HBA), L -LA/DL -α-hydroxyisovaleric acid (DL -HIVA), and L -LA/DL -α-hydroxyisocaproic acid (DL -HICA), were synthesized by quantitative direct copolycondensation without catalysts at 200°C. The in vitro degradation, which was evaluated by measuring the weight loss of these copolymers in M/15 phosphate buffer solution (pH 7,2) without enzymes at 37°C, is strongly dependent on the kind and molecular weight of these copolymers, resulting in the formation of different degradation patterns such as parabola type (L -LA/DL -HBA system), linear type (L -LA/DL -LA system), and S type (L -LA/DL -HIVA and L -LA/DL -HICA systems).  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