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   760篇
  免费   89篇
  国内免费   10篇
耳鼻咽喉   2篇
儿科学   14篇
妇产科学   4篇
基础医学   52篇
口腔科学   13篇
临床医学   201篇
内科学   114篇
皮肤病学   4篇
神经病学   30篇
特种医学   121篇
外科学   144篇
综合类   7篇
预防医学   75篇
药学   34篇
中国医学   1篇
肿瘤学   43篇
  2023年   5篇
  2021年   8篇
  2018年   18篇
  2017年   14篇
  2016年   15篇
  2015年   18篇
  2014年   26篇
  2013年   22篇
  2012年   18篇
  2011年   20篇
  2010年   16篇
  2009年   20篇
  2008年   26篇
  2007年   32篇
  2006年   30篇
  2005年   45篇
  2004年   28篇
  2003年   25篇
  2002年   36篇
  2001年   32篇
  2000年   21篇
  1999年   32篇
  1998年   29篇
  1997年   26篇
  1996年   35篇
  1995年   15篇
  1994年   20篇
  1993年   14篇
  1992年   12篇
  1991年   9篇
  1990年   12篇
  1989年   12篇
  1988年   8篇
  1987年   11篇
  1986年   14篇
  1985年   15篇
  1984年   13篇
  1983年   12篇
  1982年   5篇
  1981年   6篇
  1979年   7篇
  1978年   5篇
  1977年   4篇
  1976年   10篇
  1975年   4篇
  1974年   4篇
  1973年   10篇
  1972年   5篇
  1971年   4篇
  1969年   4篇
排序方式: 共有859条查询结果,搜索用时 12 毫秒
21.
A prospective study of the impact of training 41 hospice nurses in assessment skills was used to test hypotheses that blocking behaviours would be used more when patients disclosed feelings and used less when nurses perceived that they had satisfactory professional support Each nurse was asked to assess a patient's current problems before and after feedback training and 8 months later Audiotape recordings of these interviews were rated by trained raters They determined the frequency of nurses' responses which had the function of blocking patient disclosure and the emotional level of patient disclosure Before each patient assessment each nurse was interviewed and questionnaires administered to measure her perceptions of the support she received Blocking behaviours were most evident when patients disclosed their feelings (Kendalls r=0 36, P < 0 001) In interviews containing most patient disclosure of feeling, blocking was significantly less (r= - 0 24, P < 0 5) when the nurse felt that practical help would be available if needed and when the nurse felt that her direct supervisor was concerned about the nurse's own welfare (r= -0 37, P < 0 005)  相似文献   
22.
23.
24.
Liver Transplantation for Primary or Metastatic Sarcoma to the Liver   总被引:3,自引:0,他引:3  
Sarcoma is generally a rare disease in the US, with poor survival in patients with both primary angiosarcoma and metastatic disease from sarcoma and GIST. In order to determine if liver transplantation for sarcoma is a realistic option, we examined records of all patients in the US component of the Israel Penn International Transplant Tumor Registry were reviewed. Those patients with liver failure from primary or metastatic liver sarcoma were evaluated. Patient outcome analysis was then performed. Patient and tumor demographics were reviewed as well as patient survival after transplantation. 19 patients are identified having received liver transplantation after treatment for sarcoma of the liver, 6 patients with primary hepatic sarcoma and 13 patients with metastatic sarcoma of the liver. Recurrence was almost universal in 18 of 19 patients (95%) after a median interval of 6 months. Survival for the group as a whole was 47% for 1-year, 15% for 3-years and 5% for 5-years. Given the early recurrence of tumor and meager 1-year survival outcome, liver transplantation is a poor therapeutic choice for patients with either primary or metastatic liver sarcoma, including high-grade leiomyosarcoma (GIST) regardless of primary site or primary therapy.  相似文献   
25.
This paper is focused on selected items from an exploratory study of nurse tutor-student nurse role-relationships. Aspects of the teacher-student and counsellor-client dimensions of the relationship are reported. The research was conducted from a sociological perspective using role theory as the organizing theoretical framework. An 'ideal type' tutor-student relationship was proposed from the findings. There was concensus between tutors and students that tutors acted in a caring way towards students but many constraints were identified which inhibited students with problems from seeking help from tutors and prevented tutors from offering all the help which they wished to give to students.  相似文献   
26.
27.
Chen JM, Férec C, Cooper DN. Revealing the human mutome. The number of known mutations in human nuclear genes, underlying or associated with human inherited disease, has now exceeded 100,000 in more than 3700 different genes (Human Gene Mutation Database). However, for a variety of reasons, this figure is likely to represent only a small proportion of the clinically relevant genetic variants that remain to be identified in the human genome (the ‘mutome’). With the advent of next‐generation sequencing, we are currently witnessing a revolution in medical genetics. In particular, whole‐genome sequencing (WGS) has the potential to identify all disease‐causing or disease‐associated DNA variants in a given individual. Here, we use examples of recent advances in our understanding of mutational/pathogenic mechanisms to guide our thinking about possible locations outwith gene‐coding sequences for those disease‐causing or disease‐associated variants that are likely so often to have been overlooked because of the inadequacy of current mutation screening protocols. Such considerations are important not only for improving mutation‐screening strategies but also for enhancing the interpretation of findings derived from genome‐wide association studies, whole‐exome sequencing and WGS. An improved understanding of the human mutome will not only lead to the development of improved diagnostic testing procedures but should also improve our understanding of human genome biology.  相似文献   
28.
Heterogeneous perfusion in left bundle branch block (LBBB) has been demonstrated by (99m)Tc-methoxyisobutylisonitrile (MIBI) SPECT. Locally different contraction is also associated with LBBB. Quantitative analysis of myocardial SPECT is influenced by partial-volume effects depending on systolic wall thickening. Therefore, partial-volume effects may mimic perfusion heterogeneity in LBBB. METHODS: Fifteen patients with nonischemic dilated cardiomyopathy and LBBB underwent resting (15)O-water PET, (99m)Tc-MIBI SPECT, and gated (18)F-FDG PET for analysis of wall thickening. Myocardial blood flow corrected for rate-pressure product (corrMBF), (99m)Tc-MIBI uptake, and wall thickening were determined in 4 left ventricular wall areas. In 14 patients, M-mode echocardiographic recordings were available for comparison. RESULTS: Homogeneous distribution was found for corrMBF (1.09 +/- 0.41 to 1.19 +/- 0.31 mL x g(-1) x min(-1)). (99m)Tc-MIBI uptake and wall thickening were heterogeneous (P < 0.0001), with the lowest values septal ((99m)Tc-MIBI, 65% +/- 10%; wall thickening, 16% +/- 14%) and the highest lateral ((99m)Tc-MIBI, 84% +/- 5%; wall thickening, 55% +/- 17%). Similar relationships in systolic wall thickening were observed by M-mode echocardiography (anteroseptal, 20% +/- 11%; posterolateral, 37% +/- 18%; P < 0.001). CONCLUSION: Heterogeneity of (99m)Tc-MIBI uptake in LBBB corresponds to differences in wall thickening and does not reflect distribution of corrMBF. Supplementary analysis of wall thickening is recommended when assessing (99m)Tc-MIBI SPECT in LBBB.  相似文献   
29.
The goal of this study was to validate the accuracy of the Emory Cardiac Tool Box (ECTB) in assessing left ventricular end-diastolic or end-systolic volume (EDV, ESV) and ejection fraction (LVEF) from gated (99m)Tc-methoxyisobutylisonitrile ((99m)Tc-MIBI) SPECT using cardiac MRI (cMRI) as a reference. Furthermore, software-specific characteristics of ECTB were analyzed in comparison with 4D-MSPECT and Quantitative Gated SPECT (QGS) results (all relative to cMRI). METHODS: Seventy patients with suspected or known coronary artery disease were examined using gated (99m)Tc-MIBI SPECT (8 gates/cardiac cycle) 60 min after tracer injection at rest. EDV, ESV, and LVEF were calculated from gated (99m)Tc-MIBI SPECT using ECTB, 4D-MSPECT, and QGS. Directly before or after gated SPECT, cMRI (20 gates/cardiac cycle) was performed as a reference. EDV, ESV, and LVEF were calculated using Simpson's rule. RESULTS: Correlation between results of gated (99m)Tc-MIBI SPECT and cMRI was high for EDV (R = 0.90 [ECTB], R = 0.88 [4D-MSPECT], R = 0.92 [QGS]), ESV (R = 0.94 [ECTB], R = 0.96 [4D-MSPECT], R = 0.96 [QGS]), and LVEF (R = 0.85 [ECTB], R = 0.87 [4D-MSPECT], R = 0.89 [QGS]). EDV (ECTB) did not differ significantly from cMRI, whereas 4D-MSPECT and QGS underestimated EDV significantly compared with cMRI (mean +/- SD: 131 +/- 43 mL [ECTB], 127 +/- 42 mL [4D-MSPECT], 120 +/- 38 mL [QGS], 137 +/- 36 mL [cMRI]). For ESV, only ECTB yielded values that were significantly lower than cMRI. For LVEF, ECTB and 4D-MSPECT values did not differ significantly from cMRI, whereas QGS values were significantly lower than cMRI (mean +/- SD: 62.7% +/- 13.7% [ECTB], 59.0% +/- 12.7% [4DM-SPECT], 53.2% +/- 11.5% [QGS], 60.6% +/- 13.9% [cMRI]). CONCLUSION: EDV, ESV, and LVEF as determined by ECTB, 4D-MSPECT, and QGS from gated (99m)Tc-MIBI SPECT agree over a wide range of clinically relevant values with cMRI. Nevertheless, any algorithm-inherent over- or underestimation of volumes and LVEF should be accounted for and an interchangeable use of different software packages should be avoided.  相似文献   
30.
The purpose of this study was to evaluate a dual head coincidence gamma camera (DH-PET) equipped with single-photon transmission for 2-[fluorine-18]-fluoro-2-deoxy-d-glucose (FDG) imaging in oncological patients. Forty-five patients with known or suspected malignancies, scheduled for a positron emission tomography (PET) scan, were first studied with a dedicated ring PET and subsequently with DH-PET. All patients underwent measured attenuation correction using germanium-68 rod sources for ring PET and caesium-137 sources for DH-PET. Ring PET emission scan was started 64±17 min after intravenous administration of 235±42 MBq FDG. DH-PET emission followed 160±32 min after i.v. FDG. Attenuation-corrected and non-attenuation-corrected images were reconstructed for ring PET and DH-PET. The image sets were evaluated independently by three observers blinded to clinical data and to results of conventional imaging. Attenuation-corrected ring PET as the standard of reference depicted 118 lesions, non-attenuation-corrected ring PET 113 (96%) lesions, and attenuation-corrected DH-PET and non-attenuation-corrected DH-PET, 101 (86%) and 84 (71%) lesions, respectively (P<0.05). The lesion detection rate of attenuation-corrected and non-attenuation-corrected DH-PET was almost similar for lesions >20 mm, whereas attenuation correction increased the detection rate from 60% to 80% for lesions ≤20 mm (P<0.01). A patient-based analysis revealed concordant results relative to attenuation-corrected ring PET for non-attenuation-corrected ring PET, attenuation-corrected DH-PET and non-attenuation-corrected DH-PET in 42 (93%), 36 (80%) and 31 (69%) patients, respectively. Differences might have influenced patient management in two (4%), six (13%) and ten (22%) patients, respectively. In conclusion, measured attenuation correction markedly improves the lesion detection capability of DH-PET. With measured attenuation correction the diagnostic performance of DH-PET is closer to that of dedicated ring PET. Received 9 April and in revised form 20 April 1999  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