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   415篇
  免费   16篇
  国内免费   2篇
耳鼻咽喉   1篇
儿科学   21篇
妇产科学   10篇
基础医学   71篇
口腔科学   4篇
临床医学   22篇
内科学   56篇
皮肤病学   8篇
神经病学   56篇
特种医学   32篇
外科学   55篇
预防医学   13篇
药学   16篇
肿瘤学   68篇
  2023年   5篇
  2022年   7篇
  2021年   3篇
  2020年   5篇
  2019年   6篇
  2018年   7篇
  2017年   4篇
  2016年   6篇
  2015年   7篇
  2014年   10篇
  2013年   17篇
  2012年   21篇
  2011年   28篇
  2010年   12篇
  2009年   12篇
  2008年   22篇
  2007年   34篇
  2006年   31篇
  2005年   23篇
  2004年   30篇
  2003年   24篇
  2002年   16篇
  2001年   8篇
  2000年   8篇
  1999年   6篇
  1997年   3篇
  1996年   4篇
  1995年   3篇
  1993年   3篇
  1992年   5篇
  1991年   6篇
  1990年   7篇
  1989年   4篇
  1987年   10篇
  1986年   3篇
  1985年   7篇
  1984年   2篇
  1983年   5篇
  1982年   3篇
  1981年   3篇
  1980年   1篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1973年   1篇
  1970年   1篇
  1968年   1篇
  1966年   1篇
  1965年   1篇
  1963年   1篇
排序方式: 共有433条查询结果,搜索用时 15 毫秒
91.
Abstract  Hereditary osteoonychodysplasia (HOOD) or nail-patella syndrome (NPS) is a rare autosomal dominant disorder characterized by abnormal nail development and growth with hypoplastic highriding or absent patellae. Congenital dislocation of the radial head and bony deformities particularly around the pelvis (iliac horns) are also features. Occasionally renal dysfunction and proteinuria may be present. We report a case of nail-patella syndrome and review the literature of this rare hereditary condition.  相似文献   
92.
OBJECTIVE: To examine changes in parent-adolescent interactions after traumatic brain injury (TBI) and their relationship to parent and adolescent adjustment. DESIGN: Concurrent cohort, cross-sectional study. Analysis of variance was used to examine group differences and regression analysis to assess associations between interactional measures and concurrent adjustment. SETTING: Four hospitals in north-central Ohio. PARTICIPANTS: Adolescents with severe TBI (25), moderate TBI (22), and orthopedic injuries (35) and their parents. MAIN OUTCOME MEASURES: Observer ratings of parent-adolescent interactions, Conflict Behavior Questionnaire (CBQ), Family Burden of Injury Interview (FBII), Brief Symptom Inventory (BSI), Family Assessment Device (FAD), Child Behavior Checklist, Vineland Adaptive Behavior Scale, and Children's Depression Inventory. RESULTS: No group differences were found on ratings of parent-adolescent interaction or the parent or child CBQ. However, observed criticism/coldness and self-rated conflict had stronger associations with the FBII, BSI, and FAD in the severe TBI group than in the orthopedic injury group, suggesting that conflict is more disruptive after TBI. Ratings of criticism/coldness and parent and adolescent CBQ scores were also associated with parent and adolescent adjustment. CONCLUSIONS: Results support the utility of observational measures in assessing dyadic interactions after TBI.  相似文献   
93.
94.
Exposure to ionizing radiation has long been well-recognized as a risk factor for cancer development. Since ionizing radiation can induce mutations, an accurate way of measuring somatic mutation frequencies could be a useful tool for evaluating cancer risks. In the present study, we have examined in vivo somatic mutation frequencies at the erythrocyte glycophorin A (GPA) and T-cell receptor (TCR) loci in 18 Thorotrast patients who have been continuously irradiated with alpha-particles emitted from the internal deposition of thorium dioxide and who thus have increased risks of certain malignant tumors. When compared with controls, the results showed a significantly higher frequency of mutants at the lymphocyte TCR loci but not at the erythrocyte GPA loci in the Thorotrast patients. The discrepancy between the results of the two assays is discussed.  相似文献   
95.
96.
Mutations in human cardiac calsequestrin (CASQ2), a high-capacity calcium-binding protein located in the sarcoplasmic reticulum (SR), have recently been linked to effort-induced ventricular arrhythmia and sudden death (catecholaminergic polymorphic ventricular tachycardia). However, the precise mechanisms through which these mutations affect SR function and lead to arrhythmia are presently unknown. In this study, we explored the effect of adenoviral-directed expression of a canine CASQ2 protein carrying the catecholaminergic polymorphic ventricular tachycardia-linked mutation D307H (CASQ2(D307H)) on Ca2+ signaling in adult rat myocytes. Total CASQ2 protein levels were consistently elevated approximately 4-fold in cells infected with adenoviruses expressing either wild-type CASQ2 (CASQ2(WT)) or CASQ2(D307H). Expression of CASQ2(D307H) reduced the Ca2+ storing capacity of the SR. In addition, the amplitude, duration, and rise time of macroscopic I(Ca)-induced Ca2+ transients and of spontaneous Ca2+ sparks were reduced significantly in myocytes expressing CASQ2(D307H). Myocytes expressing CASQ2(D307H) also displayed drastic disturbances of rhythmic oscillations in [Ca2+]i and membrane potential, with signs of delayed afterdepolarizations when undergoing periodic pacing and exposed to isoproterenol. Importantly, normal rhythmic activity was restored by loading the SR with the low-affinity Ca2+ buffer, citrate. Our data suggest that the arrhythmogenic CASQ2(D307H) mutation impairs SR Ca2+ storing and release functions and destabilizes the Ca2+-induced Ca2+ release mechanism by reducing the effective Ca2+ buffering inside the SR and/or by altering the responsiveness of the Ca2+ release channel complex to luminal Ca2+. These results establish at the cellular level the pathological link between CASQ2 mutations and the predisposition to adrenergically mediated arrhythmias observed in patients carrying CASQ2 defects.  相似文献   
97.
This 2014 roundtable discussion, hosted by the Canadian Association of General Surgeons, brought together general surgeons and gastroenterologists with expertise in endoscopy from across Canada to discuss the state of endoscopy in Canada. The focus of the roundtable was the evaluation of the competence of general surgeons at endoscopy, reviewing quality assurance parameters for high-quality endoscopy, measuring and assessing surgical resident preparedness for endoscopy practice, evaluating credentialing programs for the endosuite and predicting the future of endoscopic services in Canada. The roundtable noted several important observations. There exist inadequacies in both resident training and the assessment of competency in endoscopy. From these observations, several collaborative recommendations were then stated. These included the need for a formal and standardized system of both accreditation and training endoscopists.  相似文献   
98.
A 30-year-old man presented to the Hansen outpatient department with swelling and ulceration of toes for 2 months and swelling of the right fifth and fourth fingers and the left second finger for 1 month. In addition to skin lesions of lepromatous leprosy (subpolar type), there was nontender, non-fluctuant swelling of the right fifth and fourth fingers and left second finger. Skin over the right fifth finger showed sinus-like openings with associated purulent discharge. He also had swelling and ulceration of second left toe. Slit-skin smear (SSS) showed a bacterial index of 6+ from the ear lobes and cutaneous nodules, 4+ from the patch, and 3+ from normal skin. Modified Ziehl-Neelsen staining of the discharge extruding from the sinuses on the right fifth finger also showed abundant acid-fast bacilli. Radiography of the hands and feet showed lytic lesions in the distal epimetaphyseal region o proximal phalanx of the right fifth finger and left second finger and erosion of distal end of proximal phalanges of both second toes. Histopathological examination of biopsy specimen from the patch (back) showed features of lepromatous leprosy, and Fite-Faraco stain for tissue acid-fast bacteria (AFB) was strongly positive. Fine-needle-aspiration cytology (FNAC) from the lytic lesion in the bone also showed predominantly foamy macrophages with strongly positive staining for AFB with a few interspersed lymphocytes, epithelioid cells and Langhans giant cells. On the basis of these features, a clinical diagnosis of subpolar lepromatous leprosy with leprous osteitis was made. In today's clinical era of improved case detection and prompt treatment with effective multidrug regimens, advanced bone changes are rarely encountered. We describe this case of lepromatous leprosy that developed cavitating lesions of the phalanges of the hand, seen on x-ray as well-defined bone cyst and erosions.  相似文献   
99.
The skeletal muscle sarcoplasmic reticulum (SR) was investigated for the presence of well-known endoplasmic reticulum (ER) markers: the lumenal protein BiP and a group of membrane proteins recognized by an antibody raised against ER membrane vesicles. Western blots of SR fractions revealed the presence of BiP in fast- and slow-twitch muscles of the rabbit as well as in rat and chicken muscles. Analyses of purified SR subfractions, together with cryosection immunofluorescence and immunogold labeling, revealed BiP evenly distributed within the longitudinal SR and the terminal cisternae. Within the terminal cisternae BiP appeared not to be mixed with calsequestrin but to be distributed around the aggregates of the latter Ca2+ binding protein. Of the various membrane markers only calnexin (91 kDa) was found to be distributed within both SR subfractions, whereas the other markers (apparent molecular masses of 64 kDa and 58 kDa and a doublet around 28 kDa) were concentrated in the terminal cisternae. These results suggest that the SR is a specialized ER subcompartment in which general markers, such as the ones we have investigated, coexist with the major SR proteins specifically responsible for Ca2+ uptake, storage, and release. The differential distribution of the ER markers reveals new aspects of the SR molecular structure that might be of importance for the functioning of the endomembrane system.  相似文献   
100.

Background  

Ablation of the left atrium and pulmonary veins antrum (PVAI) can be an effective treatment of atrial fibrillation (AF). However, there is discrepancy in the literature regarding the effect extensive ablation has on left atrial (LA) function. We sought to evaluate the effect that AF ablation procedures has on global and regional wall motion as assessed by cardiovascular magnetic resonance imaging (MRI).  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