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   609篇
  免费   35篇
耳鼻咽喉   12篇
儿科学   26篇
妇产科学   7篇
基础医学   131篇
口腔科学   5篇
临床医学   34篇
内科学   183篇
皮肤病学   12篇
神经病学   19篇
特种医学   9篇
外科学   103篇
综合类   10篇
预防医学   17篇
眼科学   4篇
药学   31篇
肿瘤学   41篇
  2023年   4篇
  2021年   4篇
  2020年   6篇
  2019年   4篇
  2018年   10篇
  2017年   7篇
  2016年   12篇
  2015年   10篇
  2014年   10篇
  2013年   16篇
  2012年   26篇
  2011年   27篇
  2010年   16篇
  2009年   14篇
  2008年   34篇
  2007年   40篇
  2006年   40篇
  2005年   42篇
  2004年   43篇
  2003年   36篇
  2002年   26篇
  2001年   17篇
  2000年   19篇
  1999年   24篇
  1998年   7篇
  1997年   6篇
  1995年   7篇
  1994年   13篇
  1993年   2篇
  1992年   9篇
  1991年   18篇
  1990年   10篇
  1989年   8篇
  1988年   10篇
  1987年   8篇
  1986年   12篇
  1985年   8篇
  1984年   6篇
  1983年   4篇
  1979年   4篇
  1978年   6篇
  1975年   2篇
  1972年   1篇
  1971年   2篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1967年   3篇
  1966年   1篇
  1963年   1篇
排序方式: 共有644条查询结果,搜索用时 15 毫秒
621.
Hyaluronan (HA) has been shown to play crucial roles in the tumorigenicity of malignant tumors. Chondrosarcoma, particularly when low-grade, is characterized by the formation of an extracellular matrix (ECM) containing abundant HA, and its drug/radiation resistance has become a clinically relevant problem. This study aimed to evaluate the effects of a novel hyaluronidase, KIAA1199, on ECM formation as well as antitumor effects on chondrosarcoma. To clarify the roles of KIAA1199 in chondrosarcoma, mouse KIAA1199 was stably transfected to Swarm rat chondrosarcoma (RCS) cells (histologically grade 1). We investigated the effects of KIAA1199 on RCS cells in vitro and an autografted model in vivo. HA binding protein (HABP) stainability and ECM formation in KIAA1199-RCS was markedly suppressed compared with that of control cells. No significant changes in messenger RNA expression of Has1, Has2, Has3, Hyal1, or Hyal2 were observed. KIAA1199 expression did not affect proliferation or apoptosis but inhibited migration and invasion of RCS cells. In contrast, the expression of KIAA1199 significantly inhibited the growth of grafted tumors and suppressed the stainability of alcian blue in tumor tissues. Although there was no direct inhibitory effect on proliferation in vitro, induction of KIAA1199 showed the antitumor effects in grafted tumor growth in vivo possibly due to changes in the tumor microenvironment such as inhibition of ECM formation. Forced expression of KIAA1199 exhibits antitumor effects on low-grade chondrosarcoma, which has chemo- and radio-therapy resistant features. Together, KIAA1199 could be a novel promising therapeutic tool for low-grade chondrosarcoma, mediated by the degradation of HA.  相似文献   
622.
Urinary tract infection is a bacterial infection that commonly occurs in children. Vesicoureteral reflux is a major underlying precursor condition of urinary tract infection, and an important disorder in the field of pediatric urology. Vesicoureteral reflux is sometimes diagnosed postnatally in infants with fetal hydronephrosis diagnosed antenatally. Opinions vary regarding the diagnosis and treatment of vesicoureteral reflux, and diagnostic procedures remain debatable. In terms of medical interventions, options include either follow-up observation in the hope of possible spontaneous resolution of vesicoureteral reflux with growth/development or provision of continuous antibiotic prophylaxis based on patient characteristics (age, presence/absence of febrile urinary tract infection, lower urinary tract dysfunction and constipation). Furthermore, there are various surgical procedures with different indications and rationales. These guidelines, formulated and issued by the Japanese Society of Pediatric Urology to assist medical management of pediatric vesicoureteral reflux, cover the following: epidemiology, clinical practice algorithm for vesicoureteral reflux, syndromes (dysuria with vesicoureteral reflux, and bladder and rectal dysfunction with vesicoureteral reflux), diagnosis, treatment (medical and surgical), secondary vesicoureteral reflux, long-term prognosis and reflux nephropathy. They also provide the definition of bladder and bowel dysfunction, previously unavailable despite their close association with vesicoureteral reflux, and show the usefulness of diagnostic tests, continuous antibiotic prophylaxis and surgical intervention using site markings.  相似文献   
623.
The purpose of this study is to investigate whether serum hyaluronan (HA) and serum-derived HA-associated proteins (SHAP)-HA complex predict cervical ripening and premature delivery. Sera were obtained from 64 women with normal pregnancies, 20 with full term delivery, and 13 with threatened premature labor. Concentrations of HA and SHAP-HA complex in serum were measured by sandwich ELISA. Serum concentrations of HA and SHAP-HA complex did not differ within first, second, and third trimester groups. The serum SHAP-HA complex was elevated in the full term labor group more than in the third trimester group; however, the concentrations of serum HA did not differ between both groups. The HA and SHAP-HA complex levels in sera were higher in the premature labor group than in the second trimester group. In the premature labor group, the SHAP-HA complex levels were higher in the cases with Bishop scores more than 4 points when compared with the cases with Bishop scores of 4 points or less. Increased levels of SHAP-HA complex in sera are possible predictive markers for cervical ripening in premature labor.  相似文献   
624.
IntroductionThe rate of complications for mandibular reconstruction after segmental mandibulectomy is higher with reconstruction plates than with vascularised bone grafts. We have experience of over 100 patients using reconstructive plates for reconstruction immediately after segmental mandibulectomy and have considered factors contributing to plate exposure.Patients and methodsSeventeen cases utilised our prevention methods in which reconstructive plates were used for mandibular reconstruction were reviewed. The flaps used with reconstruction plates were rectus abdominis myocutanenous flaps in 10 cases, anterolateral thigh flaps combined vastus lateralis muscle in four cases, and the omentum in one case; no flap was transferred in two cases.ResultsIn only one of 17 cases was a plate exposed at 3 months postoperatively. No plate exposure occurred during the follow-up period in the other 16 cases. Because no flap had been transferred in the patient with plate exposure, a possible contributing factor was the persistence of dead space beneath the plate.ConclusionThis series suggests that factors other than flap selection contribute to the exposure of reconstructive plates. Use of a reconstruction plate is a useful reconstructive method, especially for patients who cannot tolerate transfer of a vascularised bone graft.  相似文献   
625.
Hyaluronate plays a unique role in the cancer cell microenvironment. In particular, melanoma is the tumor type in which hyaluronate and hyaluronate recognition have been most closely linked to malignancy. In this study we show that a human melanoma cell line stably transfected with hyaluronate synthase cDNA displays enhanced motility. We used a fixed erythrocyte exclusion assay to isolate subsets of the WM793 human melanoma cell line that expressed either high or low amounts of hyaluronate. A cell line with a high level of hyaluronate on its surface (WM793H) displayed significantly higher cell motility on colloidal-gold-coated coverslips than did a line with a low level (WM793L). Next, in order to directly investigate the effects of hyaluronate on melanoma cell migration, we transfected cDNA encoding mouse hyaluronate synthase HAS1 or HAS2 into the re-cloned human melanoma cell line that produced a low amount of hyaluronate (WM793L) by the lipofection method. Several clonal transfectants differentially producing hyaluronate were obtained. There was a positive correlation between total hyaluronate synthesis and formation of the pericellular hyaluronate-rich matrix. We observed an increase in the migration ability of hyaluronate cDNA (HAS1 or HAS2)-transfected cells compared with control cells on glass plates covered with colloidal gold particles. A migration-inhibition assay with anti-CD44 monoclonal antibody showed blocking of the cell motility. It is speculated that the tumor cells might migrate through a hyaluronate-rich extracellular environment when they invade nearby host tissues and that hyaluronate production by the tumor cells could increase this migration. These results suggest that hyaluronate may play a role in the aggressiveness of human melanoma cells.  相似文献   
626.
There is a discrepancy in the reported incidence of childhood immune thrombocytopenic purpura (ITP) between Europe (2.9–5.3 per 100 000 persons) and Japan (1.91). Ise district is a suitable area in which to conduct epidemiological study because there is little fluctuation in the sociodemographic factors. We performed a retrospective population‐based study to clarify the incidence of primary childhood ITP. We calculated person‐years for children aged <15 years based on the Ise district demographics between 2002 and 2012. The calculated person‐years were 298 533. The number of hospitalized patients in Ise district was 25 (M/F, 14/11) during the study period. The calculated incidence was therefore 8.4 per 100 000 person‐years. It is possible that the difference in incidence between the present calculation and that of the European studies is due to variation in accuracy and/or registration criteria between the studies.  相似文献   
627.
628.
OBJECTIVE: To investigate social images associated with dentistry in comparison with nine other medical disciplines. DESIGN: A questionnaire survey among members of the general public. Subjects were asked to state, in not more than five words, the images which they associated with each of the ten disciplines. SETTING: Komaki City, Shikatsu Town and Nagoya City in Japan. PARTICIPANTS: 261 respondents from a convenience sample of 300 residents, not associated with any branch of medicine. OUTCOME MEASURES: Frequency distribution of word images used on at least five occasions and a correspondence analysis of the responses for the ten disciplines. RESULTS: Of the 163 coded image items, 60 were related to internal medicine, 56 to dentistry, 55 to dermatology, 51 to orthopaedic surgery, 51 to ophthalmology, 50 to surgery, 47 to obstetrics and gynaecology, 43 to otolaryngology, 40 to paediatrics and 33 to psychiatry. Correspondence analysis applied to the 163 items and 10 medical disciplines indicated that three similar paired image groups were found, namely between dermatology and ophthalmology, surgery and orthopaedic surgery, and between dentistry and internal medicine, which were the more commonly encountered disciplines across all age groups. However, compared with the other specialities, dentistry had a significantly greater association with pain, this response being four times more common than for surgery. CONCLUSIONS: This group of members of the public in Japan perceived dentistry-associated images in a similar way to internal medicine, but the negative associations with pain need to be addressed by the dental profession and health educators alike.  相似文献   
629.
630.
Alzheimer's disease (AD) is characterized by extracellular cerebral accumulation of amyloid β peptide (Aβ). Heparan sulfate (HS) is a glycosaminoglycan that is abundant in the extracellular space. The state of sulfation within the HS chain influences its ability to interact with a variety of proteins. Highly sulfated domains within HS are crucial for Aβ aggregation in vitro. Here, we investigated the expression of the sulfated domains and HS disaccharide composition in the brains of Tg2576, J20, and T41 transgenic AD mouse models, and patients with AD. RB4CD12, a phage display antibody, recognizes highly sulfated domains of HS. The RB4CD12 epitope is abundant in the basement membrane of brain vessels under physiological conditions. In the cortex and hippocampus of the mice and patients with AD, RB4CD12 strongly stained both diffuse and neuritic amyloid plaques. Interestingly, RB4CD12 also stained the intracellular granules of certain hippocampal neurons in AD brains. Disaccharide compositions in vessel-enriched and nonvasculature fractions of Tg2576 mice and AD patients were found to be comparable to those of non-transgenic and non-demented controls, respectively. The RB4CD12 epitope in amyloid plaques was substantially degraded ex vivo by Sulf-1 and Sulf-2, extracellular HS endosulfatases. These results indicate that formation of highly sulfated HS domains may be upregulated in conjunction with AD pathogenesis, and that these domains can be enzymatically remodeled in AD brains.  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