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   2878篇
  免费   145篇
  国内免费   15篇
耳鼻咽喉   23篇
儿科学   51篇
妇产科学   37篇
基础医学   308篇
口腔科学   77篇
临床医学   140篇
内科学   700篇
皮肤病学   125篇
神经病学   214篇
特种医学   126篇
外科学   558篇
综合类   12篇
预防医学   92篇
眼科学   31篇
药学   226篇
中国医学   11篇
肿瘤学   307篇
  2023年   22篇
  2022年   30篇
  2021年   50篇
  2020年   35篇
  2019年   35篇
  2018年   60篇
  2017年   47篇
  2016年   52篇
  2015年   66篇
  2014年   64篇
  2013年   76篇
  2012年   125篇
  2011年   137篇
  2010年   81篇
  2009年   85篇
  2008年   125篇
  2007年   137篇
  2006年   161篇
  2005年   116篇
  2004年   148篇
  2003年   129篇
  2002年   146篇
  2001年   90篇
  2000年   84篇
  1999年   88篇
  1998年   39篇
  1997年   37篇
  1996年   21篇
  1995年   19篇
  1994年   25篇
  1993年   15篇
  1992年   63篇
  1991年   42篇
  1990年   48篇
  1989年   56篇
  1988年   51篇
  1987年   47篇
  1986年   54篇
  1985年   52篇
  1984年   42篇
  1983年   29篇
  1982年   12篇
  1980年   13篇
  1979年   21篇
  1978年   16篇
  1977年   14篇
  1976年   12篇
  1975年   10篇
  1974年   13篇
  1971年   10篇
排序方式: 共有3038条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
Neuromedin s is a novel anorexigenic hormone   总被引:4,自引:0,他引:4  
A novel 36-amino acid neuropeptide, neuromedin S (NMS), has recently been identified in rat brain and has been shown to be an endogenous ligand for two orphan G protein-coupled receptors, FM-3/GPR66 and FM-4/TGR-1. These receptors have been identified as neuromedin U (NMU) receptor type 1 and type 2, respectively. In this study, the physiological role of the novel peptide, NMS, on feeding regulation was investigated. Intracerebroventricular (icv) injection of NMS decreased 12-h food intake during the dark period in rats. This anorexigenic effect was more potent and persistent than that observed with the same dose of NMU. Neuropeptide Y, ghrelin, and agouti-related protein-induced food intake was counteracted by coadministration of NMS. Icv administration of NMS increased proopiomelanocortin mRNA expression in the arcuate nucleus (Arc) and CRH mRNA in the paraventricular nucleus (PVN). Pretreatment with SHU9119 (antagonist for alpha-MSH) and alpha-helical corticotropin-releasing factor-(9-41) (antagonist for CRH) attenuated NMS-induced suppression of 24-h food intake. After icv injection of NMS, Fos-immunoreactive cells were detected in both the PVN and Arc. When neuronal multiple unit activity was recorded in the PVN before and after icv injection of NMS, a significant increase in firing rate was observed 5 min after administration, and this increase continued for 100 min. These results suggest that the novel peptide, NMS, may be a potent anorexigenic hormone in the hypothalamus, and that expression of proopiomelanocortin mRNA in the Arc and CRH mRNA in the PVN may be involved in NMS action on feeding.  相似文献   
55.
56.
BACKGROUND/AIMS: Solitary small-sized HCCs tend to be considered as less aggressive cancer, and non-surgical treatments have recently been preferred. The aim of this study was to clarify the clinicopathological features and the prognostic factors of small-sized HCCs and to evaluate the significance of hepatic resection for them. METHODOLOGY: Eighty patients with HCC up to 2cm in diameter who had undergone hepatic resection were enrolled in this study. We investigated the clinicopathological features and evaluated the prognostic factors by univariate and multivariate analyses. RESULTS: The overall survival rates at 3, 5 and 10 years were 83%, 69% and 36%, respectively, and the corresponding disease-free survival rates were 63%, 41% and 10%. Well-differentiated, moderately differentiated and poorly differentiated HCC were detected in 29%, 65% and 6% of the patients, respectively. Furthermore, microscopic portal vein invasion (vp), hepatic vein invasion (vv) and intrahepatic metastasis (im) were positive in 15%, 4% and 10% of the patients, respectively. Multivariate analysis revealed that Child-Pugh classification (p=0.005) and vp (p=0.0008) were independent prognostic factors for survival rate and that platelet count (p=0.002) and tumor differentiation (p=0.0016) were independent prognostic factors for disease-free survival rate. CONCLUSIONS: Even solitary small-sized (up to 2cm in diameter) HCC already have the characteristics of advanced HCC. When hepatic function is well preserved, hepatic resection should be the first choice for local control, especially in cases of moderately to poorly differentiated HCC, because the frequency of microscopic vascular invasion is high.  相似文献   
57.
The purpose of this study was to investigate whether an association exists between the promoter region of the prostacyclin synthase gene and essential hypertension (EH). Using the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method, we discovered a novel single nucleotide polymorphism (SNP), T-192G, in the 5'-flanking region. We performed an association study using the SNP in 200 patients and 200 controls. The allele frequency distribution in the two groups was not significantly different. Thus, this SNP in the PGIS gene is not associated with EH.  相似文献   
58.
Pooled sera collected from cirrhotic patients was fractionated by affinity chromatography with a fibronectin receptor monoclonal antibody against the beta-subunit of fibronectin receptor. Eluates were assayed using Western immunoblotting. The relative mobility of the protein reactive with fibronectin receptor antibody was nearly identical to that of the beta-subunit of fibronectin receptor, confirming that fibronectin receptor is present in human serum. Serum levels of the beta-subunit of fibronectin receptor were analyzed by sandwich enzyme-linked immunosorbent assay in patients with various liver diseases. The serum level of fibronectin receptor (micrograms/ml) was significantly higher in patients with chronic hepatitis (inactive, 2.59 +/- 0.04; active, 3.45 +/- 0.13), cirrhosis (4.77 +/- 0.30), alcoholic liver disease (2.96 +/- 0.16) and hepatocellular carcinoma (4.71 +/- 0.49) than in normal subjects (2.11 +/- 0.08). Strong positive correlation was observed between serum levels of fibronectin receptor and histological findings, particularly in the degree of hepatic fibrosis. Immunohistochemical studies with fibronectin receptor antibody revealed that the beta-subunit of fibronectin receptor was present on the plasma membrane of hepatocytes and sinusoidal lining cells in the normal liver and was increased in fibrotic areas and on the plasma membrane of hepatocytes and sinusoidal lining cells of fibrotic liver. The serum level of fibronectin receptor in patients with chronic liver diseases may therefore be a useful marker of hepatic fibrosis.  相似文献   
59.
The objectives of this study were to evaluate dosimetric quality and acute toxicity of volumetric-modulated arc therapy (VMAT) and daily image guidance in high-risk prostate cancer patients. A total of 100 consecutive high-risk prostate cancer patients treated with definitive VMAT with prophylactic whole-pelvic radiotherapy (WPRT) were enrolled. All patients were treated with a double-arc VMAT plan delivering 52 Gy to the prostate planning target volume (PTV), while simultaneously delivering 46.8 Gy to the pelvic nodal PTV in 26 fractions, followed by a single-arc VMAT plan delivering 26 Gy to the prostate PTV in 13 fractions. Image-guided RT was performed with daily cone-beam computed tomography. Dose–volume parameters for the PTV and the organs at risk (OARs), total number of monitor units (MUs) and treatment time were evaluated. Acute toxicity was assessed using the Common Terminology Criteria for Adverse Events, version 4.0. All dosimetric parameters met the present plan acceptance criteria. Mean MU and treatment time were 471 and 146 s for double-arc VMAT, respectively, and were 520 and 76 s for single-arc VMAT, respectively. No Grade 3 or higher acute toxicity was reported. Acute Grade 2 proctitis, diarrhea, and genitourinary toxicity occurred in 12 patients (12%), 6 patients (6%) and 13 patients (13%), respectively. The present study demonstrated that VMAT for WPRT in prostate cancer results in favorable PTV coverage and OAR sparing with short treatment time and an acceptable rate of acute toxicity. These findings support the use of VMAT for delivering WPRT to high-risk prostate cancer patients.  相似文献   
60.
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