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   10648篇
  免费   432篇
  国内免费   64篇
耳鼻咽喉   55篇
儿科学   281篇
妇产科学   81篇
基础医学   1386篇
口腔科学   243篇
临床医学   646篇
内科学   2578篇
皮肤病学   291篇
神经病学   598篇
特种医学   454篇
外科学   2064篇
综合类   38篇
一般理论   1篇
预防医学   293篇
眼科学   190篇
药学   816篇
中国医学   25篇
肿瘤学   1104篇
  2023年   48篇
  2022年   141篇
  2021年   233篇
  2020年   120篇
  2019年   151篇
  2018年   187篇
  2017年   156篇
  2016年   193篇
  2015年   215篇
  2014年   295篇
  2013年   358篇
  2012年   552篇
  2011年   634篇
  2010年   345篇
  2009年   326篇
  2008年   538篇
  2007年   572篇
  2006年   546篇
  2005年   597篇
  2004年   566篇
  2003年   565篇
  2002年   551篇
  2001年   220篇
  2000年   243篇
  1999年   213篇
  1998年   155篇
  1997年   126篇
  1996年   102篇
  1995年   99篇
  1994年   82篇
  1993年   85篇
  1992年   169篇
  1991年   169篇
  1990年   160篇
  1989年   160篇
  1988年   133篇
  1987年   132篇
  1986年   116篇
  1985年   160篇
  1984年   78篇
  1983年   65篇
  1979年   47篇
  1978年   41篇
  1977年   36篇
  1976年   39篇
  1975年   35篇
  1974年   41篇
  1973年   37篇
  1972年   48篇
  1969年   37篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
The role of insulin in controlling gastric inhibitory polypeptide (GIP) release was assessed in seven totally pancreatectomized patients, in whom inhibitory effects of endogenous pancreatic hormones on GIP secretion were excluded. In these patients, glucose was ingested on two occasions, once alone and once during insulin infusion using an artificial endocrine pancreas to maintain blood glucose at levels similar to those in normal subjects. Plasma levels of GIP, the maximum response of plasma GIP, and the integrated incremental GIP for 180 min were similar. We conclude that insulin does not alter the secretion of GIP in response to oral glucose when the influence of endogenous pancreatic hormones is excluded.  相似文献   
112.
With use of biplane cine-angiocardiograms, the measurements of right and left ventricular volume were determined in 11 children with transposition of the great arteries following Mustard's procedure. Right ventricular end-diastolic volume (RVEDV) ranged from 124 to 264 percent of the normal right ventricular volume with an average of 188 +/- 40 (SDM) percent, and left ventricular end-diastolic volume (LVEDV) ranged from 57 to 181 (122 +/- 43) percent of the normal (p less than 0.01, vs. RVEDV). Right ventricular ejection fraction (RVEF) ranged from 0.26 to 0.66 (0.42 +/- 0.11), and left ventricular ejection fraction (LVEF) ranged from 0.51 to 0.79 (0.66 +/- 0.09) (p less than 0.001, vs RVEF). Left ventriculography showed a deviation of the interventricular septum toward the left ventricle in patients with simple transposition of the great arteries not associated with left ventricular hypertension. The left to right ventricular systolic pressure ratio ranged from 0.22 to 1.02 (0.48 +/- 0.28), and the left to right ventricular end-diastolic volume ratio ranged from 0.43 to 1.00 (0.63 +/- 0.18). There was a high correlation between the left to right ventricular systolic pressure ratio and the left to right ventricular end-diastolic volume ration (r = 0.94, p less than 0.001). The left to right ventricular systolic pressure ratio also correlated well with the right ventricular ejection fraction (r = 0.90, p less than 0.001). Deviation of the interventricular septum was considered to result in a diminished ejection fraction of the right ventricle, in patients with simple transposition of the great arteries not associated with left ventricular hypertension, after Mustard's procedure.  相似文献   
113.
Desmoid tumors of the chest wall following chest surgery are a rare occurrence. A case of this disease is reported herein together with a review of the literature. A 74-year-old man, who had previously undergone a right lower lobectomy for squamous cell carcinoma of the lung, was referred to our hospital with an abnormal shadow on his chest X-ray. The tumor, located in the right lateral chest wall, was successfully resected by an aggressive, wide extirpation, and a final diagnosis of a desmoid tumor originating in the chest wall was made. When following up patients after surgery for lung cancer, the possibility of desmoid tumors developing in the incised chest wall should therefore be kept in mind.  相似文献   
114.
115.
A 58-year-old man was found to have a basaloid carcinoma of the thymus, initially detected as an abnormal shadow on chest radiograph. The patient underwent resection followed by radiotherapy, and has survived 25 months without recurrence. Although this rare tumor may be related to multilocular thymic cyst, its pathogenesis is obscure. We discuss clinicopathologic features of our case and others.  相似文献   
116.
Some hemophilic patients in Japan suffer from infections with both human immunodeficiency virus (HIV) and hepatitis virus because they received contaminated nonheated blood products. Coinfection with HIV appears to accelerate the course of chronic hepatitis. Although powerful antiviral therapy was introduced as HIV treatment and the prognosis of HIV patients was dramatically improved, the risk of rapid progression of hepatitis and carcinogenesis remains for the patients. Recently, we performed surgery for hepatocellular carcinoma (HCC) in two hemophilic patients with HIV and hepatitis C virus (HCV) coinfection. Case 1 was a 52-years-old man who suffered from liver cirrhosis, hypersplenism, and hyperammonemia due to portosystemic shunt. A recent abdominal computed tomography (CT) scan had revealed a low-density area in segment VI of the liver. Splenectomy and partial resection of the liver were performed. Case 2 was a 66-year-old man who had been diagnosed with chronic hepatitis at age 50, and HIV infection at age 52 years. When his serum alpha-fetoprotein level was increased, CT scan of the liver revealed a mass in segment VIII. Subsegmentectmy of the liver was performed. Although the CD4 value in each patient was lower than 200µl, the operations were safely carried out and no major complication occurred. Because the chance of encountering HCC patients infected with HIV and HCV is increasing in Japan, we should consider the perioperative care of these patients, as well as the protection of medical workers against HIV infection.  相似文献   
117.
Most cases of thoracic outlet syndrome are detected by neulogical symptoms, and most of the other symptoms are caused by arterial stenosis. It is rare for the syndrome to be recognized by venous symptoms. We report a 56-year-old woman with thoracic outlet syndrome recognized by arm swelling. She was admitted for radiation therapy of a recurrent tumor of lung cancer at the left apex. Her right arm gradually became swollen. We performed venography from the right median cubital vein because of suspected venous thrombosis. Venography revealed stenosis of the right subclavian vein at the costoclavicular space, and this finding was confirmed by helical CT. These findings strongly support our diagnosis of thoracic outlet syndrome.  相似文献   
118.
The aim of this study was to evaluate the clinical usefulness of attenuation and scatter correction (AC, SC) on a 201Tl myocardial single-photon emission computed tomography (201Tl SPECT) as a multi-center trial. With a dual-detecter and a triple-detector SPECT systems with a 99mTc transmission source, simultaneous transmission/emission tomography (TCT/ECT) was performed on 38 patients with angiographically coronary heart disease (CHD) and 26 patients without evidence of CHD. Stress and delayed attenuation and scatter corrected images (SAC) and uncorrected images (NC) were reconstructed. On NC images of normal cases, influence of attenuation was greater in male than female. In comparison of 201Tl distribution between male and female, significant decrease in 201Tl activity was observed in the inferoposterior wall in male and that was observed in the anterobasal wall of the left myocardium in female. Such a difference in 201Tl distribution between male and female disappeared on SAC images. On the diagnostic performance for the identification of CHD, SAC images demonstrated improved specificity and accuracy values in the right coronary arterial territory (RCA) with visual analysis statistically. Sensitivity value in the RCA was also improved, but it was not statistically significant. Sensitivity value in the left circumflex arterial territory (LCX) increased without decrease in specificity value on SAC images. In the left anterior descending arterial territory (LAD), sensitivity value increased on SAC images. Although specificity value decreased on SAC images in LAD territory, it was not statistically significant. The difference in 201Tl distribution between male and female is improved in normal cases by attenuation and scatter correction on 201Tl myocardial SPECT. Diagnostic performance of CHD is also improved by attenuation and scatter correction, especially in territories of which specificity in assessing the absence of disease have been suboptimal. In conclusion, attenuation and scatter correction on 201Tl myocardial SPECT is considered to be clinically useful.  相似文献   
119.
BACKGROUND: The high proportions of lymphoid tissues are thought to be one of the underlying factors inducing severe allograft rejection following small bowel transplantation. Mesenteric lymph nodes (MLN) contained in the intestinal graft are not only a source of donor-derived professional antigen-presenting cells, but also offer a field for immune interaction between donor and host cells. We investigated immune responses in graft MLNs with or without FK506 to develop a novel strategy to control small bowel allograft rejection. MATERIALS AND METHODS: Heterotopic small bowel transplantations were performed from Brown Norway donors to Lewis recipients. Changes in population of lymphocytes, expressions of costimulatory molecules, apoptosis, and cytokine profiles in graft MLNs were evaluated. RESULTS: The increase in apoptotic cells and cytokine responses relating to rejection in the graft MLNs developed prior to those in graft jejunum. While donor lymphocytes in graft MLNs were rapidly replaced to host-derived lymphocytes independent of FK treatment, increase in CD8(+) T cells in host population was seen only in recipients without FK506 treatment. The expressions of B7 molecules on donor cells in graft MLNs were significantly lower in the recipients with FK treatment. CONCLUSIONS: Immune responses in graft MLNs have significant impact on the outcome of the small bowel allograft. Apoptosis of graft MLN cells was well correlated with and ahead of progression of acute rejection. Modulation of costimulatory molecules on donor-derived MLN cells in the allograft and specific suppression of host CD8(+) T cells are possible ways to control severe rejection after allogeneic small bowel transplantation.  相似文献   
120.
Bone marrow chimerism and tolerance induced by single-dose cyclophosphamide   总被引:3,自引:0,他引:3  
BACKGROUND: Establishment of hematopoietic chimerism is the most stable strategy for donor-specific tolerance. Safer pretreatment regimens are needed for clinical application. We evaluated the efficacy of a simple protocol using cyclophosphamide (CYP) on induction of chimerism and organ transplant tolerance across major histocompatibility complex (MHC) barriers in the rat. MATERIALS AND METHODS: Bone marrow cells from BN (RT1(n)) donors were infused to LEW (RT1(l)) recipients on day 0 after a single injection of CYP at various doses on day -1. Donor-derived hematopoietic chimerism was evaluated by flowcytometry. The recipients received BN or third party (BUF) heart allografts on day 100. RESULTS: While pretreatment with 200 mg/kg of CYP induced high levels of hematopoietic chimerism, six of eight recipients died of severe graft-versus-host-disease (GVHD). CYP at dose of 150 mg/kg induced 36.5 +/- 24.1% of donor-derived chimerism on day 10, and sustained macrochimerism was seen until day 100 without GVHD. Pretreatment with 100 mg/kg of CYP resulted in only transient chimerism (4.8 +/- 5.2%) which disappeared by day 20. In the recipients with 50 mg/kg of CYP, donor bone marrow cells were rapidly rejected and no chimerism was observed. The recipients with 150 mg/kg of CYP accepted BN heart allografts (>100 days x 5), while rejecting BUF allografts by day 12 (n = 4). BN heart allografts were rejected in the recipients with 100 (MST: 57 days, n = 5) and 50 mg/kg (MST: 7 days, n = 5) of CYP. CONCLUSIONS: A single dose of CYP can induce hematopoietic chimerism across MHC-barriers. The dose of 150 mg/kg seems to be optimal to induce organ transplant tolerance without developing GVHD.  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