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   1321篇
  免费   51篇
  国内免费   5篇
耳鼻咽喉   19篇
儿科学   28篇
妇产科学   35篇
基础医学   106篇
口腔科学   53篇
临床医学   107篇
内科学   229篇
皮肤病学   37篇
神经病学   199篇
特种医学   99篇
外科学   255篇
综合类   3篇
预防医学   90篇
眼科学   20篇
药学   57篇
中国医学   3篇
肿瘤学   37篇
  2023年   12篇
  2022年   16篇
  2021年   27篇
  2020年   27篇
  2019年   20篇
  2018年   32篇
  2017年   24篇
  2016年   21篇
  2015年   24篇
  2014年   45篇
  2013年   67篇
  2012年   89篇
  2011年   86篇
  2010年   61篇
  2009年   48篇
  2008年   73篇
  2007年   92篇
  2006年   97篇
  2005年   108篇
  2004年   81篇
  2003年   74篇
  2002年   64篇
  2001年   13篇
  2000年   20篇
  1999年   11篇
  1998年   10篇
  1997年   4篇
  1996年   7篇
  1995年   10篇
  1994年   5篇
  1993年   7篇
  1992年   10篇
  1991年   14篇
  1990年   9篇
  1989年   3篇
  1988年   9篇
  1987年   8篇
  1986年   4篇
  1985年   5篇
  1984年   4篇
  1983年   9篇
  1982年   3篇
  1981年   5篇
  1980年   2篇
  1977年   5篇
  1975年   2篇
  1974年   3篇
  1968年   2篇
  1965年   1篇
  1959年   1篇
排序方式: 共有1377条查询结果,搜索用时 250 毫秒
61.
62.
BACKGROUND: New-onset diabetes mellitus after transplantation (NODAT) is a severe complication of kidney transplantation (KTx) with negative effects upon patient and graft survival. Several risk factors for NODAT have been described; however, the search for an early predictive marker is ongoing. It has recently been demonstrated that high concentrations of adiponectin (APN), which is an adipocyte-derived peptide with antiinflammatory and insulin-sensitizing properties, protect against future development of type 2 diabetes in healthy individuals. The purpose of this report was to study pretransplant insulin resistance and analyze pretransplant serum leptin and APN levels as independent risk factors for the development of NODAT. METHODS: A total of 68 KTx patients were studied [mean age, 48 +/- 11 years; 70% males; body mass index (BMI), 25 +/- 3 kg/m]; 31 KTx patients with NODAT and 37 KTx patients without NODAT (non-NODAT) with similar age, sex, BMI, immunosuppression, and posttransplant time were studied. All patients received prednisone and calcineurin inhibitors (75% tacrolimus and 25% cyclosporine A), and 76% of patients received mycophenolate mofetil. Family history of diabetes mellitus was recorded. Pretransplant homeostasis model assessment for insulin resistance (HOMA-IR) index was calculated from fasting plasma glucose and insulin. Pretransplant serum leptin and APN levels were determined by radioimmunoassay. RESULTS: NODAT patients showed higher pretransplant plasma insulin concentrations [NODAT, 13.4 (11-22.7) microIU/mL; non-NODAT, 10.05 (7.45-18.4) microIU/mL; P=0.049], HOMA-IR index [NODAT, 4.18 (2.49-5.75); non-NODAT, 2.63 (1.52-4.68); P=0.043], and lower pretransplant serum APN concentration [NODAT, 8.78 (7.2-11.38) microg/mL; non-NODAT, 11.4 (8.56-15.27) microg/mL, P=0.012]. Inverse correlations between APN and BMI (r=-0.33; P=0.014) and APN and HOMA-IR index (r=-0.39; P=0.002) and between APN and NODAT (r=-0.31; P=0.011) were observed. Multiple logistic regression analysis showed the patients with lower pretransplant APN concentrations to be those at greater risk of developing NODAT [Odds Ratio=0.832 (0.71-0.96); P=0.01]. CONCLUSION: Pretransplant serum APN concentration is an independent predictive factor for NODAT development in kidney-transplanted patients.  相似文献   
63.
The present study evaluated the effect of experimental sleep deprivation on attentional biases to emotional information among a sample of 40 healthy, young adults. Participants were randomized into either a total sleep deprivation (i.e., 28 consecutive hours awake) or sleep control (i.e., 8-h sleep opportunity) condition. Participants also completed a modified version of the Dot Probe Task to assess attentional biases to positive and negative information and the insomnia severity index (ISI) to assess current insomnia symptom severity. While controlling for ISI scores, acute sleep deprivation was not associated with a greater bias to negative stimuli. In contrast, sleep deprivation predicted a significantly reduced bias to positive stimuli, but only among participants with relative low ISI scores. The present findings suggest that young adults with low levels of insomnia symptoms are particularly susceptible to the effects of sleep deprivation; such that acute sleep loss can reduce their natural tendencies to attend to positive information in the environment.  相似文献   
64.
65.
Human placental tissues have been shown to contain gonadotrophin-releasing hormone-(GnRH)-like activity. Thus, the effect of a potent GnRH antagonist (N-Ac-Pro1,D-p-Cl-Phe2,D-Nal(2)3,6-GnRH, obtained from Syntex Laboratories) on placental hormonal release was studied. Explant cultures of placentae of 6 to 15 weeks' gestation were studied. This GnRH antagonist did not inhibit the alpha human chorionic gonadotrophin (alpha hCG), human chorionic gonadotrophin (hCG), oestrone or oestradiol release from the six- and nine-week placental cultures, but greatly suppressed the release of these hormones in the placental cultures from 13- and 15-week gestations. Synthetic GnRH partially reversed the action of this antagonist on the hormonal releases in the 15-week placental cultures. These data demonstrate a gestational age-related action of this antagonist on placental hormonal release. Thus, a role for the endogenous GnRH-like activity of the placenta in the control of placental hormonogenesis is indicated.  相似文献   
66.
The aim of this pictorial essay is to illustrate the distribution of normal findings and various lung diseases on coronal reconstructions as compared with cross-sectional high-resolution CT images. The volumetric CT images were obtained at 120 kVp, 200 mA/rotation, pitch 6:1, and a high-spatial-frequency reconstruction algorithm. The scans were performed using 2.5-mm collimation and reconstructed at 1.25-mm intervals. Coronal reconstructions were obtained at 2.5-mm slice thickness and 2.5-mm intervals. The pictorial includes images of normal anatomy, emphysema, idiopathic pulmonary fibrosis, Langerhans cell histiocytosis, sarcoidosis, bronchiolitis obliterans organizing pneumonia, desquamative interstitial pneumonia, nonspecific interstitial pneumonia, lymphocytic interstitial pneumonia, pulmonary edema, tuberculosis, cytomegalovirus pneumonia, bronchiectasis, and panbronchiolitis.  相似文献   
67.
Cunha MA  Schor N 《Renal failure》2002,24(6):687-690
Aminoglycosides are widely used in the treatment of gram-negative bacterial infections. Gentamicin (GE) acts mainly in proximal tubular cells, where it is uptake via organic anion transport system and it induces a high incidence of nephrotoxicity, which is characterized by tubular necrosis [5] leading to acute renal failure in 10 to 50% of patients. Gram-negative bacteria has lipopolysaccharide (LPS) which is an endotoxin that cause renal damage. [1] Moreover, many patients are undergone exams using radiologic contrast, which is a risk factor to induce a hemodynamic change in the kidney and to develop acute renal failure. [6] Intracellular calcium [Ca2+]i is involved in renal cellular injury [7,3] and maybe mediate the effects provoked by these drugs. This study was performed to evaluate necrosis, apoptosis, and intracellular calcium levels ([Ca2+]i) in LLC-PK1 (epithelial cell line from pig kidney) induced by GE associated with LPS and a low-osmolality media, Hexabrix (HE).  相似文献   
68.
69.
Acute renal failure and the sepsis syndrome   总被引:4,自引:0,他引:4  
  相似文献   
70.
PURPOSE: To characterize thin-section computed tomographic (CT) findings of pathologic subgroups of nonspecific interstitial pneumonia (NIP) in a sizeable number of patients. MATERIALS AND METHODS: The study included 55 cases of pathologically proven NIP. The 55 cases were categorized histologically into four grades: grade 1, interstitial inflammation without fibrosis (n = 6); grade 2, interstitial inflammation predominating over fibrosis (n = 16); grade 3, fibrosis predominating over inflammation (n = 5); and grade 4, fibrosis only (n = 28). Two independent observers evaluated the presence, extent, and distribution of various CT findings. Thin-section CT findings and histologic grades were compared by using the Spearman rank correlation coefficient. Observer agreement was assessed. RESULTS: Areas with ground-glass attenuation and architectural distortion were present in all 55 patients. Traction bronchiectasis and intralobular reticular opacities were seen in 52 and 48 patients, respectively. The extent of traction bronchiectasis (r = 0.68; P <.001) and intralobular reticular opacities (r = 0.35; P <.05) correlated with the histologic grade. Honeycombing was seen in 12 (43%) of 28 patients with grade 4 NIP and in three (11%) of the remaining 27 patients (chi(2) test, P <.001). There was good agreement between the observers for the presence (kappa = 0.7-1.0) and extent (Spearman rank correlation; r = 0.87-0.98; P <.001) of various abnormalities. CONCLUSION: The extent of traction bronchiectasis and intralobular reticulation at thin-section CT correlates with increased fibrosis in NIP. Honeycombing is seen almost exclusively in patients with fibrotic NIP.  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