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   23029篇
  免费   1147篇
  国内免费   145篇
耳鼻咽喉   155篇
儿科学   336篇
妇产科学   297篇
基础医学   3065篇
口腔科学   339篇
临床医学   1468篇
内科学   6283篇
皮肤病学   409篇
神经病学   1562篇
特种医学   988篇
外科学   4072篇
综合类   122篇
预防医学   600篇
眼科学   351篇
药学   1603篇
  5篇
中国医学   61篇
肿瘤学   2605篇
  2023年   168篇
  2022年   315篇
  2021年   525篇
  2020年   250篇
  2019年   349篇
  2018年   460篇
  2017年   368篇
  2016年   472篇
  2015年   490篇
  2014年   604篇
  2013年   690篇
  2012年   1188篇
  2011年   1341篇
  2010年   691篇
  2009年   679篇
  2008年   1154篇
  2007年   1352篇
  2006年   1292篇
  2005年   1261篇
  2004年   1253篇
  2003年   1274篇
  2002年   1218篇
  2001年   598篇
  2000年   561篇
  1999年   527篇
  1998年   365篇
  1997年   276篇
  1996年   265篇
  1995年   244篇
  1994年   197篇
  1993年   199篇
  1992年   375篇
  1991年   287篇
  1990年   307篇
  1989年   289篇
  1988年   257篇
  1987年   220篇
  1986年   229篇
  1985年   212篇
  1984年   169篇
  1983年   137篇
  1982年   79篇
  1980年   68篇
  1979年   146篇
  1978年   92篇
  1977年   80篇
  1975年   70篇
  1974年   72篇
  1972年   60篇
  1971年   62篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Short-latency somatosensory (SSEPs), brainstem auditory evoked potentials (BAEPs) and event-related potentials (ERPs) were studied in 7 patients with Binswanger's encephalopathy, 12 patients with Alzheimer's disease and 17 normal subjects. Patients with Binswanger's encephalopathy showed significantly prolonged central conduction time (CCT) and P300 latency, and prolonged tendency of I-V IPL compared to those of normal subjects. In particular, CCT showed significant prolongation compared to that of patients with Alzheimer's disease. In patients with Alzheimer's disease, I-V IPL and P300 latency were significantly prolonged compared to those of normals although there was no significant difference in CCT between Alzheimer's disease and normal subjects. These results indicate some difference between Binswanger's encephalopathy and Alzheimer's disease from the electrophysiological aspects although both of these entities are characterized by progressive mental deterioration.  相似文献   
62.
E Wada  A Urisu  Y Kondo  F Horiba  M Tsuruta  T Yasaki  S Masuda  K Yamada  T Kozawa  Y Hida 《Arerugī》1991,40(12):1493-1499
IgE-mediated mechanisms are important in immediate hypersensitive reactions (IHR) to buckwheat. However, a part of subjects with high IgE for buckwheat show no IHR to buckwheat ingestion. Inspite of cross-allergenicity between buckwheat and rice, rice ingestion rarely induces IHR even in subjects with high IgE for rice unlike buckwheat-induced IHR. We speculated that there were some relationships between the presence of IHR to buckwheat and recognition of cross-allergenic determinants on buckwheat components with rice components. We examined IgE-RAST for rice in 58 subjects with positive IgE-RAST for buckwheat. IgE-RAST for Dermatophagoides pteronyssinus (Dp), egg white and cow's milk as unrelated antigens with rice were also assessed for a comparison. Subjects (n = 33) without IHR to buckwheat showed higher IgE-RAST values for rice than those (n = 25) with IHR, whereas there were no differences in IgE-RAST values for Dp, egg white and cow's milk between two groups with and without IHR. IgE-RAST values for buckwheat showed significant close correlations to those for rice in subjects without IHR to buckwheat but not in those with IHR. There were no significant correlations between IgE-RAST values for buckwheat and for Dp, egg white or cow's milk in both groups with and without IHR. These results suggested that the IgE from subjects without IHR to buckwheat recognized cross-allergenic determinants with rice on the buckwheat components.  相似文献   
63.
Attempts at protein transduction into specific restricted brain areas have remained unsuccessful. We attempted targeted, direct in vivo protein transduction by microinjecting beta-galactosidase (beta-gal) with hemagglutinating virus of Japan envelope (HVJ-E) vector into the rat nucleus tractus solitarius (NTS). The medulla oblongata including the NTS was removed 6h post-injection and cryostat sections were histochemically stained to detect beta-gal enzymatic activity. beta-gal-positive cells were present in these sections as was beta-gal activity determined by colorimetric analysis. beta-gal-positive cells were not present in the rats microinjected only beta-gal protein without HVJ-E vector. Our findings suggest that direct in vivo protein transduction into specific restricted brain areas is possible. The type of targeted delivery system we present may have wide applications in the administration of therapeutic proteins to the central nervous system.  相似文献   
64.
A case of a rare renal tumor showing characteristic histo-logic features is presented. The patient was a 54 year old female, whose renal tumor was incidentally detected on abdominal ultrasound (US) examination. Ultrasound, computed tomography and angiography findings were consistent with a diagnosis of renal cell carcinoma of the hypovascular type. Left nephrectomy was performed. The tumor, which measured 2.6 times2.6 times 2.5 cm, was located in the left renal cortex, and had a uniformly whitish-yellow cut surface and well-defined margin. Histologically, the tumor was characterlzed by its monomorphous growth pattern and was composed of uniformly small cells arranged in a tubular or rosette-like pattern. The tumor cells had scant cytoplasm and the nuclei were small, round and regular. These histo-logic features resembled the epithelial elements of a metanephric hamartoma in the nephroblastomatosis complex in infants. However, there was no mitosis and cellular atypia was minimal, suggesting benignity. According to these his-tologic features, the diagnosis of metanephric adenoma was made. Its clinicopathologic features are discussed.  相似文献   
65.
The increasing complexity of diseases and advancing medical technologies have recently raised the number of test items and their use. This has caused each department to ask for clinical support by medical technologists, including consultation services on clinical laboratory tests in Japan. Under these circumstances, we think it is necessary to consider a Japanese education system for medical technologists to foster people with advanced ability capable in providing adequate clinical support. It is important that we study medical technologist systems and education systems superior to than ours. Therefore, to investigate the state of the Japanese education system for medical technologists, we conducted a comparison between the medical technologist systems and education systems in foreign countries and those of Japan. The social background in which medical technologists are positioned, their scope of work, and the education systems overseas are different from Japan on many points and we were given many suggestions for what a system in Japan should be like.  相似文献   
66.
67.
Invasive fungal infection (IFI) is a significant complication after allogeneic hematopoietic stem cell transplantation (HSCT); however, we have little information on its clinical features after reduced intensity cord blood transplantation (RICBT) for adults. We reviewed medical records of 128 patients who underwent RICBT at Toranomon Hospital between March 2002 and November 2005. Most of the patients received purine-analogbased preparative regimens. Graft-versus-host disease (GVHD) prophylaxis was a continuous infusion of either tacrolimus 0.03 mg/kg or cyclosporine 3 mg/kg. IFI was diagnosed according to the established EORTC/NIH-MSG criteria. IFI was diagnosed in 14 patients. Thirteen of the 14 had probable invasive pulmonary aspergillosis and the other had fungemia resulting from Trichosporon spp. Median onset of IFI was day 20 (range: 1-82), and no patients developed IFI after day 100. Three-year cumulative incidence of IA was 10.2%. Four of the 13 patients with invasive aspergillosis (IA) developed grade II-IV acute GVHD, and their IA was diagnosed before the onset of acute GVHD. The mortality rate of IFI was 86%. Multivariate analysis revealed that the use of prednisolone >0.2 mg/kg (relative risk 7.97, 95% confidence interval 2.24-28.4, P = .0014) was a significant risk factor for IA. This study suggests that IFI is an important cause of deaths after RICBT, and effective strategies are warranted to prevent IFI.  相似文献   
68.
Ultrastructural myeloperoxidase (MPO) activity and myeloid-associated antigen (MyAg) expression were investigated in 12 adult patients with acute lymphoblastic leukemia (ALL). Ultrastructural MPO was detected by 3 different methods. Immunophenotyping was performed by flow cytometry, using a series of monoclonal antibodies. Ultrastructural MPO-positive blast cells were detected in 6 patients (50%). In 5 of these 6 patients, the methods detecting both MPO and platelet peroxidase (PPO) activities found MPO-positive blast cells more frequently than those detecting MPO activity alone. In 2 patients (17%), at least one kind of MyAg was positive. Ultrastructural MPO activity was detected more frequently than MyAg expression in ALL patients. This method of detecting PPO and MPO is recommended for detection of ultrastructural MPO-positive ALL.  相似文献   
69.
Mutation of the adenomatous polyposis coli gene, which is known to be an early event in the carcinogenesis of intestinal-type gastric carcinoma, leads to accumulation of beta-catenin. In addition, beta-catenin has been found to activate down stream signaling molecules in the wingless/Wnt pathway. In this study, the clinical significance of nuclear accumulation of beta-catenin was evaluated in gastric carcinoma. Immunohistochemical staining showed nuclear localization in 16 (12%) of 139 (94 intestinal-type and 45 diffuse-type) gastric carcinomas, and all 16 lesions with nuclear staining were intestinal-type adenocarcinomas. Of the 16 cases, 15 were in the early clinical stage. In the remaining case, the lesion had invaded the subserosal layer and showed strong nuclear staining at the invasive front. In 14 of the 16 cases with nuclear localization, there were no abnormal mobility shifts detected using polymerase chain reaction-single strand conformational polymorphism analysis. This was confirmed using direct sequencing analysis, which revealed the wild-type sequence in the 12 cases tested. Nuclear accumulation of beta-catenin did not correlate with lymph node metastasis or 5-year survival. These findings suggest that high intranuclear levels of beta-catenin protein play an important role in early tumor growth and may function in initiation of invasive processes in intestinal-type gastric carcinoma.  相似文献   
70.
Prostate cancer is a major cause of cancer death among elderly men in America, Europe, and Japan. However, the molecular mechanism of carcinogenesis is not yet well characterized. Frequent loss of heterozygosity (LOH) on chromosome 10q was reported in prostate cancer, and a candidate tumor suppressor gene, PTEN, was isolated on chromosome band 10q23.3. To investigate the genetic alterations of PTEN, we examined 45 primary prostate cancer specimens. LOH at the PTEN locus was observed in two (11.1%) of 18 tumors. However, no mutations were observed in any of the primary prostate cancers. These data suggest that mutation of the PTEN gene does not play a major role in prostate carcinogenesis of Japanese patients. Received: February 6, 1998 / Accepted: July, 3, 1998  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