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   9001篇
  免费   435篇
  国内免费   148篇
耳鼻咽喉   176篇
儿科学   150篇
妇产科学   87篇
基础医学   1682篇
口腔科学   129篇
临床医学   850篇
内科学   1757篇
皮肤病学   206篇
神经病学   552篇
特种医学   504篇
外科学   1108篇
综合类   33篇
一般理论   2篇
预防医学   339篇
眼科学   254篇
药学   891篇
中国医学   92篇
肿瘤学   772篇
  2024年   3篇
  2023年   63篇
  2022年   241篇
  2021年   359篇
  2020年   180篇
  2019年   205篇
  2018年   268篇
  2017年   209篇
  2016年   260篇
  2015年   408篇
  2014年   518篇
  2013年   557篇
  2012年   788篇
  2011年   760篇
  2010年   451篇
  2009年   393篇
  2008年   542篇
  2007年   600篇
  2006年   502篇
  2005年   439篇
  2004年   315篇
  2003年   288篇
  2002年   230篇
  2001年   204篇
  2000年   202篇
  1999年   174篇
  1998年   51篇
  1997年   40篇
  1996年   27篇
  1995年   22篇
  1994年   20篇
  1993年   28篇
  1992年   37篇
  1991年   29篇
  1990年   26篇
  1989年   22篇
  1988年   16篇
  1987年   22篇
  1986年   15篇
  1985年   12篇
  1984年   5篇
  1983年   6篇
  1982年   5篇
  1979年   6篇
  1978年   6篇
  1977年   4篇
  1976年   3篇
  1975年   3篇
  1970年   3篇
  1968年   4篇
排序方式: 共有9584条查询结果,搜索用时 0 毫秒
991.
Koh YY  Jung da E  Koh JY  Kim JY  Yoo Y  Kim CK 《Chest》2007,131(5):1454-1460
BACKGROUND: Measles virus infection may progress to a chronic obstructive process including bronchiolitis obliterans (BO). This study investigates pulmonary cellular profiles and interleukin (IL)-8 levels in patients with BO following the measles. METHODS: BAL fluid was obtained from 12 children with BO who had a history of measles pneumonia during an outbreak in 2000 and 2001. BAL cell counts and differentials were compared to control patients as well as BAL IL-8 levels, which were measured by enzyme-linked immunosorbent assay. Immunohistochemical staining of BAL cells and three open-lung biopsy specimens were also analyzed for T-cell surface markers CD3, CD4, and CD8. RESULTS: BAL cellular profiles were characterized by a significantly increased percentage of neutrophils in the measles BO group (median, 16.0%) compared to the control group (2.3%) [p < 0.01]. BAL IL-8 levels were also markedly increased in the measles BO group (mean +/- SD, 418.6 +/- 286.0 pg/mL) compared to the control group (92.8 +/- 126.7 pg/mL) [p < 0.01]. BAL IL-8 levels correlated significantly with neutrophil percentages in both the measles BO group (r = 0.86, p = 0.000) and the control group (r = 0.79, p = 0.007). The lymphocyte subsets were characterized by a significantly increased number of CD8+ cells, resulting in a decreased CD4/CD8 ratio in the BAL and the biopsy specimens. CONCLUSION: These results suggest that pulmonary neutrophils and IL-8, along with CD8+ T lymphocytes may play an important role in the pathogenesis of BO after measles virus infection.  相似文献   
992.
From June 1997 to August 2005, 52 consecutive newly diagnosed stage 4 neuroblastoma patients over 1 year of age were assigned to receive tandem high-dose chemotherapy and autologous stem cell rescue (HDCT/ASCR) as consolidation therapy. Fifty of the 52 patients underwent a first HDCT/ASCR and 44 patients underwent a second HDCT/ASCR. Eight patients (15.4%) died from treatment-related toxicity (seven during the second HDCT/ASCR). Total body irradiation (TBI) in the first HDCT/ASCR and a shorter interval (< 12 weeks) between the first and second HDCT/ASCR were associated with a higher rate of treatment-related death in the second HDCT/ASCR (P = 0.032 and 0.095, respectively). The tumor relapsed or progressed in 11 patients, and 33 patients remained event free with a median follow-up of 53 months (range 19-117) from diagnosis. The 5-year event-free survival (EFS) (+/- 95% confidence interval) for all 52 patients was 62.1+/-13.7%. The application of TBI and local radiotherapy, and a longer interval between the first and second HDCT/ASCR were independently associated with a better EFS (P = 0.026, 0.007 and 0.020, respectively). However, further studies will be needed to decrease the toxic death rate in the second HDCT/ASCR while reducing the relapse rate.  相似文献   
993.
OBJECTIVE: To investigate the effect of cyclosporine on cytokine production, especially on T helper 1 (Th1) and T helper 2 (Th2) type cytokines, in patients with rheumatoid arthritis (RA). METHODS: A 16 week randomized, double blind, placebo controlled study of cyclosporine (2.5 to 4 mg/kg/day) was conducted in 40 patients with severe, refractory RA who had residual inflammation and disability despite partial responses to prior maximal tolerated dose of methotrexate (MTX; < 15 mg/week) and low dose prednisone (< 10 mg/day). Clinical and laboratory variables, and circulating levels of interleukin 2 (IL-2), IL-4, IL-10, IL-12, tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma) measured by ELISA were compared between patients (cyclosporine group) treated with cyclosporine plus MTX and those (placebo group) treated with placebo plus MTX at entry and at 16 weeks. RESULTS: At 16 weeks, the cyclosporine group (n = 17), compared with the placebo group (n = 17), had greater decreases in tender joints, swollen joints, patient global assessment, patient self-assessed disability, and C-reactive protein, as well as having more patients with > 20% improvement. Comparison of circulating cytokines at entry and at 16 weeks showed significant decreases of IL-2 (median -61 vs 7 pg/ml; p = 0.004) ("+" denotes increase, "-" denotes decrease), IL-12 (median -313 vs -14 pg/ml; p = 0.002), TNF-alpha (median -55 vs 5 pg/ml; p < 0.001), and IFN-gamma (median -21 vs 5 pg/ml; p = 0.003), and a significant increase of IL-10 (median 55 vs -12 pg/ml; p < 0.001) in the cyclosporine group compared with the placebo group. The degree of IL-10 increases correlated strongly with the degree of IL-12 decreases in the cyclosporine group (r = 0.572, p = 0.016). However, there was no change in circulating IL-4 between the 2 groups. Within the cyclosporine group, the improved patients (n = 10) compared to the non-improved patients (n = 7) had a greater increase in circulating IL-10 (median 172.0 vs 85.2%; p = 0.01). The rate of increase of IL-10 strongly correlated with the rate of improvement of joint scores (r = 0.718, p = 0.001) after administration of cyclosporine. CONCLUSION: Our results suggest that the therapeutic effect of cyclosporine is achieved by correcting a Th1/Th2 imbalance (a shift of Th1 type to Th2 type), which may be involved in the pathogenesis of RA; and that circulating IL-10 is useful to assess the clinical improvements in patients with RA after administration of cyclosporine.  相似文献   
994.
Seiki Kiriyama  Kazuto Kozaka  Tadahiro Takada  Steven M. Strasberg  Henry A. Pitt  Toshifumi Gabata  Jiro Hata  Kui‐Hin Liau  Fumihiko Miura  Akihiko Horiguchi  Keng‐Hao Liu  Cheng‐Hsi Su  Keita Wada  Palepu Jagannath  Takao Itoi  Dirk J. Gouma  Yasuhisa Mori  Shuntaro Mukai  Mariano Eduardo Giménez  Wayne Shih‐Wei Huang  Myung‐Hwan Kim  Kohji Okamoto  Giulio Belli  Christos Dervenis  Angus C. W. Chan  Wan Yee Lau  Itaru Endo  Harumi Gomi  Masahiro Yoshida  Toshihiko Mayumi  Todd H. Baron  Eduardo de Santibañes  Anthony Yuen Bun Teoh  Tsann‐Long Hwang  Chen‐Guo Ker  Miin‐Fu Chen  Ho‐Seong Han  Yoo‐Seok Yoon  In‐Seok Choi  Dong‐Sup Yoon  Ryota Higuchi  Seigo Kitano  Masafumi Inomata  Daniel J. Deziel  Eduard Jonas  Koichi Hirata  Yoshinobu Sumiyama  Kazuo Inui  Masakazu Yamamoto 《Journal of hepato-biliary-pancreatic sciences》2018,25(1):17-30
Although the diagnostic and severity grading criteria on the 2013 Tokyo Guidelines (TG13) are used worldwide as the primary standard for management of acute cholangitis (AC), they need to be validated through implementation and assessment in actual clinical practice. Here, we conduct a systematic review of the literature to validate the TG13 diagnostic and severity grading criteria for AC and propose TG18 criteria. While there is little evidence evaluating the TG13 criteria, they were validated through a large‐scale case series study in Japan and Taiwan. Analyzing big data from this study confirmed that the diagnostic rate of AC based on the TG13 diagnostic criteria was higher than that based on the TG07 criteria, and that 30‐day mortality in patients with a higher severity based on the TG13 severity grading criteria was significantly higher. Furthermore, a comparison of patients treated with early or urgent biliary drainage versus patients not treated this way showed no difference in 30‐day mortality among patients with Grade I or Grade III AC, but significantly lower 30‐day mortality in patients with Grade II AC who were treated with early or urgent biliary drainage. This suggests that the TG13 severity grading criteria can be used to identify Grade II patients whose prognoses may be improved through biliary drainage. The TG13 severity grading criteria may therefore be useful as an indicator for biliary drainage as well as a predictive factor when assessing the patient's prognosis. The TG13 diagnostic and severity grading criteria for AC can provide results quickly, are minimally invasive for the patients, and are inexpensive. We recommend that the TG13 criteria be adopted in the TG18 guidelines and used as standard practice in the clinical setting. Free full articles and mobile app of TG18 are available at: http://www.jshbps.jp/modules/en/index.php?content_id=47 . Related clinical questions and references are also included.  相似文献   
995.
We present three cases of focal eosinophilic infiltration in the liver that mimicked hepatic malignancy on computed tomography during hepatic arteriography (CTHA) and computed tomography during arterial portography (CTAP). In all patients, focal eosinophilic liver infiltration appeared as a solitary nodule or as two nodules without hepatosplenomegaly and showed homogeneous hyperattenuation on CTHA and hypoattenuation on CTAP. Received: 10 June 1998/Revision accepted: 26 August 1998  相似文献   
996.

Background

Drinking coffee can raise public health problems, but the association between coffee and kidney disease is unknown. We studied whether coffee intake can affect the development of chronic kidney disease in the general population.

Methods

We analyzed 8717 subjects with normal renal function recruited from the Korean Genome and Epidemiology Study (KoGES) cohort. Based on a food frequency questionnaire, coffee consumption was categorized into 5 groups: 0 per week, <1 cup per week, 1-6 cups per week, 1 cup per day, and ≥2 cups per day. The primary outcome was incident chronic kidney disease, defined as an estimated glomerular filtration rate <60 mL/min/1.73 m2.

Results

The mean age (standard deviation) of study subjects was 52.0 (8.8) years, and 47.8% were male. Among the subjects, 52.8% were daily coffee consumers. During a mean follow-up of 11.3 (range, 5.9-11.5) years, 9.5% of participants developed chronic kidney disease. The incident chronic kidney disease occurred less in daily coffee consumers. Unadjusted hazard ratios (HRs) was significantly lower in daily coffee consumers. In multivariable Cox model even after adjustment of blood pressure, hypertension, cardiovascular disease, diabetes, and amount of daily intake for caffeine-containing foods such as tea and chocolate, coffee consumers with 1 cup per day (HR, 0.76; 95% confidence interval, 0.63-0.92) and ≥2 cups per day (HR, 0.80; 95% confidence interval, 0.65-0.98) were associated with a lower risk of chronic kidney disease development than nondrinkers. Time-averaged and time-varying Cox models yielded similar results. The rates of decline in glomerular filtration were lower in daily coffee consumers.

Conclusions

Our findings suggest that daily coffee intake is associated with decreased risk of the development of chronic kidney disease.  相似文献   
997.
Melatonin plays an important role in regulating circadian rhythms. It also acts as a potent antioxidant and regulates glucose and lipid metabolism, although the exact action mechanism is not clear. The α2‐HS‐glycoprotein gene (AHSG) and its protein, fetuin‐A (FETUA), are one of the hepatokines and are known to be associated with insulin resistance and type 2 diabetes. The aim of this study was to determine whether melatonin improves hepatic insulin resistance and hepatic steatosis in a FETUA‐dependent manner. In HepG2 cells treated with 300 μmol/L of palmitic acid, phosphorylated AKT expression decreased, and FETUA expression increased, but this effect was inhibited by treatment with 10 μmol/L of melatonin. However, melatonin did not improve insulin resistance in FETUA‐overexpressing cells, indicating that improvement in insulin resistance by melatonin was dependent on downregulation of FETUA. Moreover, melatonin decreased palmitic acid‐induced ER stress markers, CHOP, Bip, ATF‐6, XBP‐1, ATF‐4, and PERK. In addition, in the high‐fat diet (HFD) mice, oral treatment with 100 mg/kg/day melatonin for 10 weeks reduced body weight gain to one‐third of that of the HFD group and hepatic steatosis. Insulin sensitivity and glucose intolerance improved with the upregulation of muscle p‐AKT protein expression. FETUA expression and ER stress markers in the liver and serum of HFD mice were decreased by melatonin treatment. In conclusion, melatonin can improve hepatic insulin resistance and hepatic steatosis through reduction in ER stress and the resultant AHSG expression.  相似文献   
998.
A 17‐year‐old male with acute lymphoblastic leukemia developed severe hematuria and scrotal swelling after haploidentical hematopoietic cell transplantation (HCT). Urine culture was negative. BK virus and adenovirus were negative. However, Ureaplasma urealyticum was detected. He showed dramatic improvement after doxycycline treatment. This is the first report in the literature of hemorrhagic cystitis caused by U. urealyticum in a HCT recipient. In HCT recipients with hemorrhagic cystitis, U. urealyticum should be considered as a potential cause.  相似文献   
999.
1000.

Objective

The purpose of this study was to evaluate the changes in right ventricle (RV) and left ventricle (LV) function after transcatheter atrial septal defect (ASD) closure and to assess the influence of the age and the amount of shunt.

Design

Retrospective study

Patients

Fifty‐three adult patients who underwent transcatheter closure were enrolled, then divided into subgroups according to the age (< 40 years vs ≥ 40 years), and the amount of shunt flow (QpQs < 2.5 vs QpQs ≥ 2.5).

Outcome Measures

Two‐dimensional tissue Doppler imaging was performed in a four‐chamber view at the basal ventricular septum (VS) and tricuspid valve annulus (TVA) before and at 1 month and 6 months after closure. Myocardial velocities, the myocardial performance index (MPI), and isovolumic acceleration (IVA) were assessed.

Results

At the TVA, the MPI decreased slightly and then greatly increased at 6 months after closure (P = .002). The IVA improved in all patients (P < .001), and the E′/A′ ratio decreased, especially in the old age group (P = .031) and larger shunt group (P = .035). At the VS, S′ and the IVA decreased and had not recovered until 6 months in the old age (P = .02) and larger shunt (P = .02). The Qp/Qs showed a significant reverse correlation with a decrease in the E′/A′ at the TVA (r = ?0.37, P = .008), and age of patient was correlated with a decrease in the IVA at the VS (r = ?0.32, P = .019). The age at closure (β = ?0.36, P = .002), the Qp/Qs ratio (β = ?0.45, P = .01), and RV MPI changes (β = ?7.64, P < .001) were found to be associated factors with IVA decrease at the VS.

Conclusions

After ASD closure, RV global function might be impaired. In elderly patients and patients with a large shunt, impairment of LV contractility developed until 6 months after closure. Close long‐term observation is required after closure, especially in old‐age patients with a large shunt.  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