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   992篇
  免费   45篇
  国内免费   32篇
儿科学   14篇
妇产科学   15篇
基础医学   96篇
口腔科学   18篇
临床医学   90篇
内科学   129篇
皮肤病学   128篇
神经病学   32篇
特种医学   133篇
外科学   138篇
综合类   93篇
预防医学   26篇
眼科学   4篇
药学   74篇
肿瘤学   79篇
  2021年   11篇
  2019年   10篇
  2018年   5篇
  2017年   11篇
  2016年   13篇
  2015年   19篇
  2014年   16篇
  2013年   26篇
  2012年   34篇
  2011年   31篇
  2010年   19篇
  2009年   25篇
  2008年   39篇
  2007年   52篇
  2006年   37篇
  2005年   36篇
  2004年   27篇
  2003年   24篇
  2002年   28篇
  2001年   27篇
  2000年   33篇
  1999年   33篇
  1998年   44篇
  1997年   31篇
  1996年   23篇
  1995年   22篇
  1994年   20篇
  1993年   16篇
  1992年   9篇
  1991年   23篇
  1990年   15篇
  1989年   17篇
  1988年   23篇
  1987年   23篇
  1986年   25篇
  1985年   18篇
  1984年   20篇
  1983年   16篇
  1982年   15篇
  1981年   16篇
  1980年   14篇
  1979年   15篇
  1978年   16篇
  1977年   5篇
  1975年   15篇
  1974年   5篇
  1971年   4篇
  1968年   4篇
  1966年   6篇
  1919年   4篇
排序方式: 共有1069条查询结果,搜索用时 15 毫秒
41.

Background

HBV DNA quantitation is used extensively world wide for the diagnosis and monitoring of treatment of Hepatitis B virus (HBV) infection. However, it has still to be popular in India. The aim of this study was to quantitate HBV – DNA by Real time – PCR method in Hepatitis B and in immuno-compromised patients, to compare the results with HBeAg detection and to monitor the response to therapy of chronic Hepatitis B patients to antivirals.

Methods

Ninety one serum samples of Hepatitis group of patients (all HBsAg positive), 41 samples from immuno-compromised patients (all HBsAg negative) and 49 patients of Chronic Hepatitis B group (all HBsAg positive) were the subjects of this first ever study in Armed Forces. Twenty serum samples from healthy volunteers and non-hepatitis B patients served as negative controls. The amplification detection was carried out in a Rotor-Gene 2000-sequence detector

Results

Amongst Hepatitis B group, 33% (30/91) of the samples were positive for HBV-DNA and 26% (24/91) of samples were positive for HBeAg. In the immuno-compromised group of patients 14.6% (6/11) of samples were positive for HIV-DNA and 9.7% (4/41) were positive for HBeAg. Of the Chronic Hepatitis B patients on treatment, all (100%) were positive by HBV-DNA, whereas 29/49 (59.2%) were positive by HBeAg before treatment. After treatment with antivirals, 06/49 (12.2%) were positive by both tests and 11/49 (22.5%) were positive only by HBV-DNA. 32/49 (65.3%) patients became negative serologically after therapy.

Conclusion

HBeAg status did not necessarily reflect HBV-DNA level in the serum, as 10/91 (11%) in the Hepatitis B group, 2/41 (4.9%) in the immuno compromised group and 20/49 (40.8%) patients in the Chronic Hepatitis B group were positive for HBV-DNA but negative for HBeAg. HBV-DNA was not found to be positive amongst any of the negative controls. Real time – PCR is a sensitive and reproducible assay for HBV-DNA quantitation and may be started in Armed Forces referral centers in the near future.Key Words: Real time – PCR, Chronic Hepatitis B, HBV – DNA, Antivirals  相似文献   
42.
The prevalence of congenital-nevus-like nevi (CNLN) in a group of 105 adults who had malignant melanoma (MM) was compared with that in a control group of 601 adults not afflicted by MM. Total cutaneous examinations were performed on both groups. The control group presented with complaints other than pigmented lesions. In this series, 10 (9.5%) of the group with MM had clinically diagnosed CNLN 1.5 cm or larger in diameter. These CNLN were not in contiguity with the MM sites. The 9.5% prevalence of CNLN in the group with MM was significantly higher (p less than 0.005) than the 2.5% CNLN observed in the control population. None of the patients in either group had large congenital nevocytic nevi (greater than or equal to 20 cm). In addition, in the group with MM, 5 patients (4.8%) had nevi spili (NS) and 13 (12.4%) had café-au-lait spots (CLS). The prevalence rates for these two types of pigmented lesions were not significantly different from those observed in the nonmelanoma control group (2.3% for NS; 13.8% for CLS). The relative risk for developing MM is 4.1 in people with CNLN compared with those without CNLN, which indicates that these nevi may be markers for individuals prone to develop malignant melanoma.  相似文献   
43.
We have reviewed 44 consecutive patients undergoing myocardial revascularization from 1 to 42 days after myocardial infarction. Operation within 12 days of transmural myocardial infarction carried a substantially high risk, particularly in patients with poor ventricular function. Patients with subendocardial infarction may be safely operated on shortly after infarction has occurred. In those with transmural infarcts, it may be advantageous to delay operation if early and aggressive medical therapy can effectively control the symptoms. This has to be counterbalanced, however, by the realization that the situation should not be allowed to slide into one of irreparable ventricular damage from infarct extension.  相似文献   
44.
45.
Marsland BJ  Kopf M  Le Gros G 《Nature immunology》2004,5(9):865; author reply 865-865; author reply 866
  相似文献   
46.
PURPOSE: Short term hyperglycemia has previously been shown to induce a blood flow increase in the retina. The mechanism behind this effect is poorly understood. We set out to investigate whether exercise-induced hyperlactatemia may alter the response of retinal blood flow to hyperglycemia. METHODS: We performed a randomized, controlled two-way cross over study comprising 12 healthy subjects, performed a 6-minutes period of dynamic exercise during an euglcaemic or hyperglycaemic insulin clamp. Retinal blood flow was assessed by combined vessel size measurement with the Zeiss retinal vessel analyzer and measurement of red blood cell velocities using bi-directional laser Doppler velocimetry. Retinal and systemic hemodynamic parameters were measured before, immediately after and 10 and 20 minutes after isometric exercise. RESULTS: On the euglycemic study day retinal blood flow increased after dynamic exercise. The maximum increase in retinal blood flow was observed 10 minutes after the end of exercise when lactate plasma concentration peaked. Hyperglycemia increased retinal blood flow under basal conditions, but had no incremental effect during exercise induced hyperlactatemia. CONCLUSIONS: Our results indicate that both lactate and glucose induce an increase in retinal blood flow in healthy humans. This may indicate a common pathway between glucose and lactate induced blood flow changes in the human retina.  相似文献   
47.
48.
49.
Gonadotropin releasing hormone (GnRH) is a hypothalamic decapeptide that binds to GnRH receptors on pituitary gonadotrope cells to modulate the synthesis and secretion of the gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These gonadotropins in turn regulate gonadal steroidogenesis and gametogenesis. Chemical characterization and structure-activity analysis of GnRH variants containing systematic amino acid substitutions led to the discovery of GnRH superagonists and antagonists. These peptides are widely used for the treatment of clinical conditions in which modulation of or interference with sex hormone production is beneficial to prevent development or progression of benign conditions (e.g. endometriosis, uterine fibroids) or malignant tumors (e.g. breast, ovarian, endometrial and prostate carcinoma). When compared to native GnRH, GnRH superagonists have increased potency for the short-term release of gonadotropins. However, they show paradoxical action in that chronic treatment with superagonists results in inhibition of gonadotropin production as a result of desensitization of the gonadotropes and down regulation of its receptor. In contrast, GnRH antagonists produce a rapid and dose-dependent suppression of gonadotropin release by competitive blockade of the GnRH receptors without any initial stimulatory effect as seen with superagonists. In recent years, a search for peptidomimetic compounds to replace peptides as therapeutic agents has been undertaken to find compounds with higher affinity for the GnRH receptor but do not have the disadvantages of peptides. Such efforts have resulted in the identification and development of small-molecule non-peptide compounds that are sufficiently stable in vivo and possess favorable pharmacological parameters comparable to peptide antagonists. Some of these compounds are being tested in human volunteers and the preliminary results are very encouraging.  相似文献   
50.

Background  

The Major Depression Inventory (MDI) is a brief self-rating scale for the assessment of depression. It is reported to be valid because it is based on the universe of symptoms of DSM-IV and ICD-10 depression. The aim of the current preliminary study was to assess the reliability, validity and psychometric properties of the Greek translation of the MDI.  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