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   4490篇
  免费   252篇
  国内免费   30篇
耳鼻咽喉   53篇
儿科学   138篇
妇产科学   111篇
基础医学   529篇
口腔科学   148篇
临床医学   349篇
内科学   1033篇
皮肤病学   142篇
神经病学   334篇
特种医学   208篇
外国民族医学   1篇
外科学   605篇
综合类   25篇
一般理论   1篇
预防医学   175篇
眼科学   130篇
药学   299篇
中国医学   18篇
肿瘤学   473篇
  2024年   7篇
  2023年   58篇
  2022年   113篇
  2021年   188篇
  2020年   103篇
  2019年   144篇
  2018年   183篇
  2017年   138篇
  2016年   139篇
  2015年   144篇
  2014年   166篇
  2013年   203篇
  2012年   336篇
  2011年   378篇
  2010年   187篇
  2009年   171篇
  2008年   284篇
  2007年   244篇
  2006年   249篇
  2005年   215篇
  2004年   211篇
  2003年   203篇
  2002年   183篇
  2001年   57篇
  2000年   65篇
  1999年   37篇
  1998年   36篇
  1997年   22篇
  1996年   33篇
  1995年   16篇
  1994年   8篇
  1993年   7篇
  1992年   25篇
  1991年   12篇
  1990年   19篇
  1989年   10篇
  1988年   10篇
  1987年   12篇
  1985年   18篇
  1983年   10篇
  1981年   8篇
  1980年   9篇
  1979年   19篇
  1978年   8篇
  1976年   10篇
  1972年   7篇
  1971年   9篇
  1970年   6篇
  1969年   6篇
  1968年   6篇
排序方式: 共有4772条查询结果,搜索用时 0 毫秒
41.
Although adenovirus vectors (Ad) provide high-level transduction efficacy to many cell types, extremely high doses of Ad are required for sufficient gene transduction into several tumors, including melanoma. Here, we demonstrated that the expression of coxsackie-adenovirus receptor, a primitive Ad-receptor, was very low in murine and human melanoma cells. We also found that fiber-mutant Ad containing the Arg-Gly-Asp (RGD) sequence in the fiber knob remarkably augmented gene transduction efficacy in melanoma cells by targeting alpha(v)-integrins. In addition, intratumoral injection of RGD fiber-mutant Ad containing the tumor necrosis factor alpha gene (Ad-RGD-TNFalpha) revealed dramatic anti-tumor efficacy through hemolytic necrosis in an established murine B16 BL6 melanoma model. Ad-RGD-TNFalpha required one-tenth the dosage of Ad-TNFalpha to induce an equal therapeutic effect. These results suggest that alpha(v)-integrin-targeted Ad will be a very powerful tool for the advancement of melanoma gene therapy.  相似文献   
42.
Nine hundred eight women aged 40-88 years living in a non-Cd-polluted area in Japan were analyzed for urinary cadmium (Cd), N-acetyl-beta-D-glucosaminidase (NAG) activity, beta(2)-microglobulin (B2MG) concentration, and for the stiffness index (STIFF) of calcaneal bone using an ultrasound method. The urinary Cd in the subjects, with a mean and range of 2.87 and 0.25-11.4 microg/g creatinine, respectively, showed a significant correlation with NAG but not with B2MG. STIFF was significantly inversely correlated with urinary Cd, and the association remained significant after adjusting for age, body weight, and menstrual status, suggesting a significant effect of Cd on the bone loss in these subjects without signs of Cd-induced kidney damage. A two-fold increase in urinary Cd was accompanied by a decrease in STIFF corresponding to a 1.7-year rise in age. These results emphasize the need for reassessment of the significance of Cd exposure in the general Japanese population.  相似文献   
43.
Gestational diabetes mellitus (GDM) is one of the most common pregnancy‐related complications; it is associated with adverse pregnancy outcomes and metabolic disorders in offspring, consistent with the concept of the developmental origins of health and disease. This cohort study of women without diabetes (n = 761), who were part of the Yamanashi Adjunct Study of the Japan Environment and Children’s Study, aimed to explore the associations between maternal GDM and their offspring’s level of high‐sensitivity C‐reactive protein (hsCRP), a biomarker of inflammatory and cardiovascular diseases. We analyzed the associations between GDM and the offspring’s hsCRP levels using a multiple logistic regression model. A mother with GDM significantly increased the risk for high hsCRP level by 4.07‐fold (≥2.0 mg/L) in the child. As such, maternal GDM was significantly associated with increased serum hsCRP levels in 8‐year‐old children.  相似文献   
44.
The novel coronavirus-19 (COVID-19) pandemic has considerably impacted children’s lives. The aim of this study was to determine whether the pandemic affected mealtime regularity among preschool children and whether maintaining regular mealtimes or changes in mealtime regularity during the pandemic were related to dietary balance, including chronological relationships. This online cross-sectional survey involving individuals registered with a company that provides meals to children aged 2−6 years was conducted in February 2021. Using a 40-point scale, a healthy diet score (HDS) was developed to evaluate children’s dietary balance. The participants were divided into four groups based on their responses, and multiple regression analyses were performed with the HDS as the dependent variable. Maintaining regular mealtimes was associated with practices such as waking and going to bed earlier, less snacking, and eating breakfast every day. Even after adjusting for basic attributes, lifestyle habits, household circumstances, and other factors, regular mealtimes were still positively correlated with the HDS. These findings indicate that maintaining regular mealtimes is associated with higher HDS scores and better lifestyle habits. Furthermore, as the changed HDS was higher in the group whose mealtimes became regular during the pandemic, adopting regular mealtimes may lead to a more balanced diet.  相似文献   
45.
46.
This retrospective study clarified the success rate of endoscopic endodontic surgeries and identified predictors accounting for successful surgeries. In this retrospective study, 242 patients (90 males, 152 females) who underwent endoscopic endodontic surgery at a single general hospital and were diagnosed through follow-up one year later were included. Risk factors were categorized into attributes, general health, anatomy, and surgery. Then, the correlation coefficient was calculated for the success or failure of endodontic surgery for each variable, the odds ratio was calculated for the upper variable, and factors related to the surgical prognosis factor were identified. The success rate of endodontic surgery was 95.3%, showing that it was a highly predictable treatment. The top three correlation coefficients were post, age, and perilesional sclerotic signs. Among them, the presence of posts was the highest, compared with the odds ratio, which was 9.592. This retrospective study revealed the success rate and risk factors accounting for endoscopic endodontic surgeries. Among the selected clinical variables, the presence of posts was the most decisive risk factor determining the success of endodontic surgeries.  相似文献   
47.
BACKGROUND: Use of the inferior mesenteric vein (IMV) for partial portal decompression has not been recommended as a first-line option for intractable gastroesophageal variceal bleeding because of the thin diameter of the vein. Although these indications remain relevant, few reports have compared partial portal decompression using the IMV with other therapies. We propose that partial portal decompression using the IMV is a useful alternative treatment for intractable variceal bleeding. METHODS: We performed partial portal decompression using the IMV in eight patients with intractable variceal bleeding that had been uncontrolled using medical and endoscopic therapies. All patients were classified into Child's class B or C. The surgical data, morbidity, and mortality were assessed. RESULTS: Mean portal venous pressure significantly decreased from 26.9 +/- 2.0 mmHg before the surgery to 19.8 +/- 3.9 mmHg after the surgery. The operative mortality rate was 0%. The mean duration of hospital stay was 25.5 +/- 13.3 days. Although one patient experienced recurrent bleeding, shunt patency was well maintained in all patients during the follow-up period (mean 28.9 +/- 14.1 months). Six patients are still alive and well without ascites or hepatic encephalopathy. Two of the Child's class C patients who underwent emergency shunt died owing to hepatic decompensation. CONCLUSION: Partial portal decompression using the IMV can be a safe, effective way to treat intractable variceal bleeding in patients with liver cirrhosis. However, use of the shunt procedure may have the most survival benefits for cirrhotic patients with preserved liver function.  相似文献   
48.
49.

Background

Information on young patients with Brugada syndrome (BrS) and arrhythmic events (AEs) is limited.

Objectives

The purpose of this study was to describe their characteristics and management as well as risk factors for AE recurrence.

Methods

A total of 57 patients (age ≤20 years), all with BrS and AEs, were divided into pediatric (age ≤12 years; n = 26) and adolescents (age 13 to 20 years; n = 31).

Results

Patients’ median age at time of first AE was 14 years, with a majority of males (74%), Caucasians (70%), and probands (79%) who presented as aborted cardiac arrest (84%). A significant proportion of patients (28%) exhibited fever-related AE. Family history of sudden cardiac death (SCD), prior syncope, spontaneous type 1 Brugada electrocardiogram (ECG), inducible ventricular fibrillation at electrophysiological study, and SCN5A mutations were present in 26%, 49%, 65%, 28%, and 58% of patients, respectively. The pediatric group differed from the adolescents, with a greater proportion of females, Caucasians, fever-related AEs, and spontaneous type-1 ECG. During follow-up, 68% of pediatric and 64% of adolescents had recurrent AE, with median time of 9.9 and 27.0 months, respectively. Approximately one-third of recurrent AEs occurred on quinidine therapy, and among the pediatric group, 60% of recurrent AEs were fever-related. Risk factors for recurrent AE included sinus node dysfunction, atrial arrhythmias, intraventricular conduction delay, or large S-wave on ECG lead I in the pediatric group and the presence of SCN5A mutation among adolescents.

Conclusions

Young BrS patients with AE represent a very arrhythmogenic group. Current management after first arrhythmia episode is associated with high recurrence rate. Alternative therapies, besides defibrillator implantation, should be considered.  相似文献   
50.

Background  

Nonalcoholic steatohepatitis (NASH) is a feature of metabolic syndrome. Advanced glycation end-products (AGEs) are formed by the Maillard reaction, which contributes to aging and to certain pathological complications of diabetes. A recent study has suggested that glyceraldehyde-derived AGEs (Glycer-AGEs) are elevated in the sera of patients with NASH. Furthermore, immunohistochemistry of Glycer-AGEs showed intense staining in the livers of patients with NASH. The present study aimed to examine the effect of intracellular Glycer-AGEs on hepatocellular carcinoma (Hep3B) cells.  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