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   20482篇
  免费   1434篇
  国内免费   72篇
耳鼻咽喉   347篇
儿科学   613篇
妇产科学   356篇
基础医学   2452篇
口腔科学   258篇
临床医学   2031篇
内科学   4497篇
皮肤病学   482篇
神经病学   2012篇
特种医学   723篇
外科学   2948篇
综合类   243篇
现状与发展   1篇
一般理论   18篇
预防医学   1854篇
眼科学   557篇
药学   1289篇
中国医学   23篇
肿瘤学   1284篇
  2023年   109篇
  2022年   207篇
  2021年   457篇
  2020年   288篇
  2019年   426篇
  2018年   539篇
  2017年   367篇
  2016年   434篇
  2015年   471篇
  2014年   690篇
  2013年   984篇
  2012年   1401篇
  2011年   1491篇
  2010年   798篇
  2009年   769篇
  2008年   1247篇
  2007年   1358篇
  2006年   1329篇
  2005年   1290篇
  2004年   1300篇
  2003年   1124篇
  2002年   1009篇
  2001年   233篇
  2000年   184篇
  1999年   230篇
  1998年   256篇
  1997年   177篇
  1996年   159篇
  1995年   169篇
  1994年   142篇
  1993年   120篇
  1992年   137篇
  1991年   112篇
  1990年   89篇
  1989年   107篇
  1988年   103篇
  1987年   98篇
  1986年   114篇
  1985年   95篇
  1984年   111篇
  1983年   86篇
  1982年   99篇
  1981年   120篇
  1980年   95篇
  1979年   86篇
  1978年   78篇
  1977年   82篇
  1976年   50篇
  1975年   53篇
  1974年   50篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
OBJECTIVE: Septal-lateral annular cinching ('SLAC') corrects both acute and chronic ischemic mitral regurgitation in animal experiments, which has led to the development of therapeutic surgical and interventional strategies incorporating this concept (e.g., Edwards GeoForm ring, Myocor Coapsys, Ample Medical PS3). Changes in left ventricular (LV) transmural cardiac and fiber-sheet strains after SLAC, however, remain unknown. METHODS: Eight normal sheep hearts had two triads of transmural radiopaque bead columns inserted adjacent to (anterobasal) and remote from (midlateral equatorial) the mitral annulus. Under acute, open chest conditions, 4D bead coordinates were obtained using videofluoroscopy before and after SLAC. Transmural systolic strains were calculated from bead displacements relative to local circumferential, longitudinal, and radial cardiac axes. Transmural cardiac strains were transformed into fiber-sheet coordinates (X(f), X(s), X(n)) oriented along the fiber (f), sheet (s), and sheet-normal (n) axes using fiber (alpha) and sheet (beta) angle measurements. Results: SLAC markedly reduced (approximately 60%) septal-lateral annular diameter at both end-diastole (ED) (2.5+/-0.3 to 1.0+/-0.3 cm, p=0.001) and end-systole (ES) (2.4+/-0.4 to 1.0+/-0.3 cm, p=0.001). In the LV wall remote from the mitral annulus, transmural systolic strains did not change. In the anterobasal region adjacent to the mitral annulus, ED wall thickness increased (p=0.01) and systolic wall thickening was less in the epicardial (0.28+/-0.12 vs 0.20+/-0.06, p=0.05) and midwall (0.36+/-0.24 vs 0.19+/-0.11, p=0.04) LV layers. This impaired wall thickening was due to decreased systolic sheet thickening (0.20+/-0.8 to 0.12+/-0.07, p=0.01) and sheet shear (-0.15+/-0.07 to -0.11+/-0.04, p=0.02) in the epicardium and sheet extension (0.21+/-0.11 to 0.10+/-0.04, p=0.03) in the midwall. Transmural systolic and remodeling strains in the lateral midwall (remote from the annulus) were unaffected. CONCLUSIONS: Although SLAC is an alluring concept to correct ischemic mitral regurgitation, these data suggest that extreme SLAC adversely effects systolic wall thickening adjacent to the mitral annulus by inhibiting systolic sheet thickening, sheet shear, and sheet extension. Such alterations in LV strains could result in unanticipated deleterious remodeling and warrant further investigation.  相似文献   
92.
In October 2003, over 200 nurse leaders from education and practice met at the invitation of the American Association of Colleges of Nursing. A newly released white paper, describing the role of the clinical nurse leader, was discussed at the conference. This article outlines a response to that white paper from one practice setting. The article shares information about another role, that of team coordinator, that is similar to clinical nurse leader and has been implemented at an integrated not-for-profit health care system in 5 hospitals. The comparison of the team coordinator role to the clinical nurse leader role might assist in visualizing such a role in practice. Although the roles are not identical, many of the driving forces for change were similar; these included the need to meet the changing demands for improved patient outcomes and nurse retention. The team coordinator role has 4 domains of practice that are crosswalked against the clinical nurse leader 15 core competencies. An evaluation of the team coordinator role showed changes that need to be made, such as placing more emphasis on clinical progression of patients. Lessons learned are shared, including keeping the scope of the role manageable, providing documentation standards for new roles, and the leadership required of the nursing executive to implement change.  相似文献   
93.
PURPOSE: While the mode of inheritance of a genetic condition has long been considered to have not only medical, but also psychosocial consequences for families, this supposition has never been tested. METHODS: We surveyed 112 members of 51 families (59% response) with chronic granulomatous disease to determine the influence of mode of inheritance on parents', siblings', and patients' (1) knowledge of inheritance and reproductive risk; (2) concern about risk to future family-members; (3) feelings of guilt and blame; and (4) feelings of stigmatization. Ninety-six members of 51 families (49% response) with Duchenne/Becker muscular dystrophy and spinal muscular atrophy types II/III were also studied. RESULTS: X-linked families had better understanding of inheritance (P < 0.001) and reproductive risks (P < 0.01). X-linked mothers worried more about risks to future generations; other autosomal-recessive family members were as worried. X-linked mothers were more likely to feel guilty (P < 0.01) and blame themselves (P < 0.001). X-linked fathers blamed their child's mother (P < 0.05) and X-linked mothers felt more blamed by the father (P < 0.01). X-linked family-members were more likely to consider being a carrier stigmatizing (P < 0.05). CONCLUSION: When providing genetic counseling, attention should be given to guilt and blame in X-linked families and understanding reproductive risks in autosomal recessive families.  相似文献   
94.
OBJECTIVES: To examine ventilatory support for the VLBW infant over the past 10 years in a single academic NICU and determine factors that predicted length of ventilation, death, and CLD. STUDY DESIGN: A retrospective cohort review of neonatal blood gases, ventilatory support, and clinical outcomes. RESULTS: From 1992 through October 2002, 6254 infants were admitted, of whom 2388 required intubation for mechanical ventilation. Of these, 837 were <1500 g at birth (VLBW) infants and 453 were less than 1000 g (ELBW). Total duration of ventilation decreased in all weight groups. Noninvasive ventilatory support increased from 20 to 55% of total ventilation from 1997 to 2002. During this same period, CLD decreased from 20 to 11% in ventilated VLBW infants. Duration of total ventilation was best predicted by birth weight, with each 100 g increment decreasing the duration of ventilation by 71 hours. Lower birth weight, male sex, and a longer total duration of ventilatory support were significant factors in predicting the occurrence of CLD. Death alone was best predicted by lower birth weight and maximum oxygen index (OI). Transported infants had significantly increased maximal OIs, durations of ventilation, and incidence of death. A total of 48% of infants with a single OI >10 either died or survived with CLD. CONCLUSIONS: Birth weight is the best predictor of duration of ventilation, and CLD is best predicted by birth weight, duration of ventilation and male sex. The increasing use of noninvasive strategies has not been associated with an observable increase in respiratory morbidity. VLBW infants with a single OI>10 may benefit from inclusion in future interventional rescue studies.  相似文献   
95.
Tamponade caused by cardiac lipomatous hypertrophy.   总被引:1,自引:0,他引:1  
Cardiac lipomatous hypertrophy is an unusual disorder that typically affects the interatrial septum. We report a case in which large subpericardial deposits of fat were initially mistaken for a pericardial effusion and the subsequent clinical picture resembled tamponade. The patient improved following a pericardiectomy.  相似文献   
96.
Solution Focused Brief Therapy (SFBT) focuses on clients' strengths and expressed goals in an attempt to produce therapeutic change as quickly as possible. This study examined whether clients seen for SFBT were seen for fewer sessions than those seen for cognitive behaviour therapy (CBT) in a clinical psychology service taking adult referrals from primary care. The study was a retrospective one using pseudo-randomization. The results indicated that SFBT clients (n = 41) were seen for two sessions on average compared to five for CBT (n = 119). This difference was accounted for by a higher proportion of the SFBT group being seen for one session only, which is consistent with the approach. A simple therapist-rated outcome scale showed no significant difference between the two groups. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
97.
98.
The aim of our study was to characterize the parental perceptions of the behavioral and emotional functioning of their children and families coping with gastrointestinal motility disorders. The American Pseudo-obstruction and Hirschsprung's disease Society sponsored an educational meeting for parents of children afflicted with a variety of pediatric gastrointestinal motility disorders. During the conference, parents completed a questionnaire pertaining to the behavioral and emotional functioning of the afflicted child and other family members. Parents perceived that the child's illness was more difficult on the parents than on the affected child or their siblings. Also, parents perceived support from professionals, family, and friends increased after the children were diagnosed with pediatric gastrointestinal motility disorders. Parents worried most about the health and medical management of their afflicted child. The most common behavioral problem of the afflicted children was fear of separation, whereas the most common behavioral problem of their siblings was jealousy. The majority of referrals to mental health professionals resulted from parental emotional problems or marital discord.  相似文献   
99.
The use of split-liver (SL) allografts continues to be an excellent option for many pediatric recipients. Patient and graft survival with this graft type are comparable to patient and graft survival with whole organ grafts. Quality-of-life issues, specifically growth, for SL recipients have not been compared to those of recipients of more conventional whole-organ recipients. Pediatric recipients of SL and whole allografts at 2 institutions were identified. Height, z score, and delta z score were calculated for all recipients for each year after transplant. Between 1995 and 2004, 201 pediatric liver transplants were analyzed. Data were collected on 39 split-graft recipients and 36 whole-size recipients. Only subjects 3 years or younger were included in the study. Growth retardation was present in all recipients at transplant. Height z score post split and whole-size transplant were not statistically different at 1- (P = 0.65), 2- (P = 0.13), and 3-year (P = 0.32) anniversaries, respectively. Catch-up growth was present only in recipients of split grafts. In conclusion, the use of split grafts as opposed to whole-size grafts revealed no significant differences in terms of linear growth. Our report indicates that split-liver transplantation does not impair recipient growth.  相似文献   
100.
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