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   2732篇
  免费   196篇
  国内免费   29篇
耳鼻咽喉   77篇
儿科学   100篇
妇产科学   41篇
基础医学   389篇
口腔科学   108篇
临床医学   225篇
内科学   468篇
皮肤病学   93篇
神经病学   114篇
特种医学   366篇
外科学   259篇
综合类   99篇
预防医学   130篇
眼科学   120篇
药学   154篇
中国医学   13篇
肿瘤学   201篇
  2023年   19篇
  2022年   35篇
  2021年   74篇
  2020年   53篇
  2019年   60篇
  2018年   73篇
  2017年   46篇
  2016年   68篇
  2015年   73篇
  2014年   83篇
  2013年   117篇
  2012年   127篇
  2011年   161篇
  2010年   94篇
  2009年   101篇
  2008年   141篇
  2007年   123篇
  2006年   88篇
  2005年   106篇
  2004年   79篇
  2003年   80篇
  2002年   65篇
  2001年   83篇
  2000年   53篇
  1999年   45篇
  1998年   52篇
  1997年   57篇
  1996年   49篇
  1995年   45篇
  1994年   27篇
  1993年   34篇
  1992年   33篇
  1991年   40篇
  1990年   28篇
  1989年   35篇
  1988年   49篇
  1987年   67篇
  1986年   37篇
  1985年   32篇
  1984年   18篇
  1983年   23篇
  1982年   21篇
  1981年   24篇
  1980年   27篇
  1979年   17篇
  1977年   21篇
  1976年   30篇
  1975年   26篇
  1972年   11篇
  1971年   12篇
排序方式: 共有2957条查询结果,搜索用时 187 毫秒
61.
Nasal polyposis is often encountered in rhinology practice. Those who fail conservative management, a definitive surgery is essential to achieve sufficient ventilation and drainage of the affected sinuses by using either microdebrider or conventional instruments for functional endoscopic sinus surgery (FESS). A prospective study was conducted on 40 cases of nasal polypi in a tertiary care hospital. 20 cases were operated by conventional endoscopic instruments and 20 using the microdebrider. The study aimed at comparing the intra operative (blood loss, duration of surgery) and post operative results (crusting, scarring, discharge, symptoms, recurrence) between the two groups using Lund–Mackay scoring system and the data was statistically analysed. There was no statistically significant difference in surgical outcome for patients when either conventional endoscopic instruments or microdebrider was used. However, there was a significant symptomatic improvement in cases undergoing microdebrider FESS. Microdebrider assisted polypectomy is precise, relatively bloodless surgery though the precision depends on the surgeon’s anatomical knowledge and operative skills. Study substantiates that these instruments are helpful but not a prerequisite for successful outcomes in FESS. The study re-emphasises the utility of the microdebrider to young learning FESS surgeons.  相似文献   
62.
Mucormycosis is a rare but life-threatening disease with high morbidity and mortality and is difficult to diagnose. Mucormycosis, is a severe but rare fungal infection caused by a group of molds called mucormycetes. Diabetes, use of corticosteroids, metabolic/diabetic acidosis and Covid-19 mediated immunosuppression are reported in more than 70% of cases in mucormycosis patients. Coexisting mucormycosis, Covid-19 along with diabetes mellitus increase the likelihood of mortality. Despite its occurrence since the beginning of the pandemic, there are still unanswered concerns regarding the origin of this fungal infection and mortality rate and/or relation with diabetic patients. In this review, we describe the detailed view of causative pathogens responsible for mucormycosis, diabetes mellitus and Covid-19 association along with the morbidity cases during the latest Covid-19 crisis. In the case of mucormycosis diagnosis, imaging, histopathological confirmation, fungal culture and molecular identification methods should be considered. Once mucormycosis is diagnosed, a combined treating method consisting of antifungals administration like amphotericin B, surgical intervention is needed for the reversal of the underlying condition. Early detection of this potentially life-threatening infection and timely care is needed in lowering mortality rates.  相似文献   
63.
64.
The anti-microbial compound triclosan is incorporated into numerous consumer products and is detectable in the urine of 75% of the general United States population. Recent epidemiological studies report positive associations with urinary triclosan levels and allergic disease. Although not sensitizing, earlier studies previously found that repeated topical application of triclosan augments the allergic response to ovalbumin (OVA) though a thymic stromal lymphopoietin (TSLP) pathway in mice. In the present study, early immunological effects following triclosan exposure were further evaluated following topical application in a murine model. These investigations revealed abundant expression of S100A8/A9, which reportedly acts as an endogenous ligand for Toll-like Receptor 4 (TLR4), in skin tissues and in infiltrating leukocytes during topical application of 0.75–3.0% triclosan. Expression of Tlr4 along with Tlr1, Tlr2 and Tlr6 increased in skin tissues over time with triclosan exposure; high levels of TLR4 were expressed on skin-infiltrating leukocytes. In vivo antibody blockade of the TLR4/MD-2 receptor complex impaired local inflammatory responses after four days, as evidenced by decreased Il6, Tnfα, S100a8, S100a9, Tlr1, Tlr2, Tlr4 and Tlr6 expression in the skin and decreased lymph node cellularity and production of IL-4 and IL-13 by lymph node T-cells. After nine days of triclosan exposure with TLR4/MD-2 blockade, impaired T-helper cell type 2 (TH2) cytokine responses were sustained, but other early effects on skin and lymph node cellularity were lost; this suggested alternative ligands/receptors compensated for the loss of TLR4 signaling. Taken together, these data suggest the S100A8/A9-TLR4 pathway plays an early role in augmenting immunomodulatory responses with triclosan exposure and support a role for the innate immune system in chemical adjuvancy.  相似文献   
65.

Background and Aims

Various prognostic scores are available for predicting outcome in acute-on-chronic liver failure (ACLF). We compared the available prognostic models as predictors of outcome in alcohol-related ACLF patients.

Methods

All consecutive patients with alcohol-related ACLF were included. At admission, prognostic indices-acute physiology and chronic health evaluation score (APACHE II), model for end-stage liver disease (MELD), MELD-Na, Maddrey’s discriminant function (DF), age-bilirubin-INR-creatinine (ABIC), and Chronic Liver Failure Consortium (CLIF-C) ACLF score (CLIF-C ACLF) score were calculated. Receiver operator characteristic (ROC) curves were plotted for all prognostic scores with in-hospital, 90-day, and 1-year mortality as outcome.

Results

Of the 171 patients, 170 were males, and grade 1 ACLF in 20 (11.7%), grade 2 in 52 (30.4%), and grade 3 in 99 (57.9%) patients. One hundred and nineteen (69.6%) died in-hospital. The median (IQR) Maddrey’s score, MELD, MELD-Na, ABIC, APACHE II, and CLIF-C ACLF were 87.8 (66.5–123.0), 33.1 (27.6–40.0), 34.4 (29.5–40.0), 8.5 (7.3–9.6), 15 (12–21), and 51.1 (44.1–56.4), respectively. On multivariate Cox regression analysis, independent predictors of in-hospital outcome were presence of hepatic encephalopathy (early HR, 2.078; 95%CI, 1.173–3.682, p?=?0.012 and advanced, HR, 2.330; 95% CI, 1.270–4.276, p?=?0.006), elevated serum creatinine (HR, 1.140; 95% CI, 1.023–1.270, p?=?0.018), and infection at admission (HR, 1.874; 95% CI, 1.160–23.029, p?=?0.010). On comparison of ROC curves, APACHE II and CLIF-C ACLF AUROC were significantly higher than MELD, MELD-Na, DF, and ABIC (p?<?0.05) for predicting in-hospital, 90-day, and 1-year mortality. The AUROC was highest for APACHE II followed by CLIF-C ACLF (Hanley and McNeil, p?=?0.660).

Conclusions

Alcohol-related ACLF has high in-hospital mortality. Among the available prognostic scores, CLIF-C ACLF and APACHE II perform best.
  相似文献   
66.
Allergic rhinitis (AR) is a common chronic condition in children and may impact a child's quality of life. Increasing treatment compliance may improve quality of life. An oral suspension of fexofenadine hydrochloride (HCl) has been developed to ease administration to children and may, therefore, improve treatment compliance. The purpose of this study was to assess the pharmacokinetic behavior, safety, and tolerability of a single dose of fexofenadine HCl oral suspension administered to children aged 2-5 years with allergic rhinitis. Children (aged 2-5 years) with AR were recruited in a multicenter, open-label, single-dose study. Fexofenadine HCl (30 mg) was administered as a 6-mg/mL suspension (5 mL). Plasma samples were collected up to 24 hours postdose. Adverse events (AEs); electrocardiograms (ECGs); vital signs; and clinical laboratory tests for hematology, blood chemistry, and urinalysis were analyzed to evaluate safety and tolerability. Fifty subjects completed the study. Mean maximum plasma concentration of fexofenadine was 224 ng/mL, and mean area under the plasma concentration curve was 898 ng . hour/mL. Treatment-emergent AEs were mild in intensity and reported in a total of seven subjects. No trends or clinically meaningful changes in mean ECG, vital sign, or clinical laboratory test data occurred during the study. In children aged 2-5 years, the exposure after a 30-mg dose of fexofenadine HCl suspension was similar to the exposures previously seen after a 30- and 60-mg dose of fexofenadine HCl in children aged 6-11 years and in adults, respectively. The suspension was also well tolerated.  相似文献   
67.
BACKGROUND & AIMS: Shwachman syndrome is an inherited condition with multisystemic abnormalities, including exocrine pancreatic dysfunction. The aim of this study was to evaluate the occurrence and progression of features in a large cohort of patients. METHODS: Clinical records of 25 patients with Shwachman syndrome were reviewed. RESULTS: Mean birth weight (2.92 +/- 0.51 kg) was at the 25th percentile. However, by 6 months of age, mean heights and weights were less than the 5th percentile. After 6 months of age, growth velocity was normal. Severe fat maldigestion due to pancreatic insufficiency was present in early life (fecal fat, 26% +/- 17% of fat intake; age, < 2 years). Serial assessment of exocrine pancreatic function showed persistent deficits of enzyme secretion, but 45% of patients showed moderate age-related improvements leading to pancreatic sufficiency. Neutropenia was the most common hematologic abnormality (88%), but leukopenia, thrombocytopenia, and anemia were also frequently encountered. Patients with hypoplasia of all three bone marrow cellular lines (n = 11) had the worst prognosis; 5 patients died, 2 of sepsis and 3 of acute myelogenous leukemia. Other findings included hepatomegaly and/or abnormal liver function test results and skeletal abnormalities. CONCLUSIONS: A wide and varied spectrum of phenotypic abnormalities among patients with Shwachman syndrome is described. Pancreatic acinar dysfunction is an invariable abnormality. Patients with severe bone marrow involvement may have a guarded prognosis. (Gastroenterology 1996 Dec;111(6):1593-602)  相似文献   
68.
INTRODUCTION: Nonsustained ventricular tachycardia (NSVT) is a frequent phenomenon in some patients with heart disease, but its association with sustained ventricular tachycardias (ventricular tachycardia [VT]/ventricular fibrillation [VF]) is still not clear. The aim of this study was to determine whether NSVT incidence was associated with sustained VT/VF in patients with an implantable cardioverter defibrillator (ICD). METHODS AND RESULTS: Retrospective data analysis was conducted in 923 ICD patients with a mean follow-up of 4 months. NSVT and sustained VT/VF were defined as device-detected tachycardias. The incidence rates of NSVT and sustained VT/VF as well as ICD therapies were determined as episodes per patient. The NSVT index was defined as the product of NSVT episodes/day times the mean number of beats per episode, i.e., total beats/day. The NSVT index peak was defined as the highest value on or prior to the day with sustained VT/VF episodes. Patients (n = 393) with NSVT experienced a higher incidence of sustained VT/VF (17.2 +/- 63.0 episodes/patient) and ICD therapies (15.2 +/- 61.4 episodes/patient) than patients (n = 530) without NSVT (sustained VT/VF: 0.5 +/- 6.6 and therapies: 0.5 +/- 5.6; P < 0.0001). Approximately 74% of NSVT index peaks occurred on the same day or <3 days prior to sustained VT/VF episodes. The index was higher for peaks < or =3 days prior to the day with sustained VT/VF (94.3 +/- 140.1 total beats/day) than for peaks >3 days prior to the day with sustained VT/VF (32.7 +/- 55.9 total beats/day; P < 0.0001). CONCLUSION: ICD patients with NSVT represent a population more likely to experience sustained VT/VF episodes with a temporal association between an NSVT surge and sustained VT/VF occurrence.  相似文献   
69.
In the human heart there is a sequential contraction of the systemic veins, systemic venous sinus and the pectinated right atrium, 'the systemic waltz', and sequential contraction of the pulmonary veins, pulmonary venous sinus and pectinated left atrium, 'the pulmonary waltz'. The systemic veins contract earlier than the pulmonary veins creating a 'duet. We hypothesise that this waltz and duet point to a complex extracardiac control of the cardiac rhythm on a beat-to-beat neural basis.  相似文献   
70.
In a patient with tetralogy of Fallot (TOF) and pulmonary atresia, treating the cardiac problem or the associated congenital illness is always a challenge. We describe the challenges and successful initial management of bilateral cataract to prevent visual loss in an infant with TOF with pulmonary atresia.  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