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   488篇
  免费   37篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   8篇
妇产科学   7篇
基础医学   55篇
口腔科学   15篇
临床医学   41篇
内科学   101篇
皮肤病学   13篇
神经病学   20篇
特种医学   9篇
外科学   161篇
综合类   6篇
预防医学   28篇
眼科学   12篇
药学   27篇
中国医学   3篇
肿瘤学   18篇
  2024年   1篇
  2023年   7篇
  2022年   20篇
  2021年   36篇
  2020年   17篇
  2019年   24篇
  2018年   22篇
  2017年   23篇
  2016年   14篇
  2015年   10篇
  2014年   24篇
  2013年   33篇
  2012年   40篇
  2011年   39篇
  2010年   20篇
  2009年   12篇
  2008年   23篇
  2007年   30篇
  2006年   10篇
  2005年   17篇
  2004年   16篇
  2003年   7篇
  2002年   7篇
  2001年   6篇
  2000年   8篇
  1999年   4篇
  1998年   1篇
  1997年   1篇
  1996年   4篇
  1995年   2篇
  1994年   2篇
  1993年   1篇
  1992年   4篇
  1991年   4篇
  1990年   2篇
  1989年   8篇
  1988年   4篇
  1987年   6篇
  1986年   3篇
  1985年   1篇
  1984年   2篇
  1983年   3篇
  1982年   2篇
  1981年   2篇
  1970年   2篇
  1967年   2篇
排序方式: 共有526条查询结果,搜索用时 0 毫秒
1.
2.
Gamma irradiation alters bluetongue virus protein antigen.   总被引:1,自引:0,他引:1  
Bluetongue virus (BTV) antigen, prepared for a monoclonal antibody (MAb)-based competitive enzyme-linked immunosorbent assay (C-ELISA), was exposed to 1, 2, 3, 4, 5 and 6 Mrad of gamma irradiation. The major group-specific BTV protein (VP7) reactive with the Mab was altered at higher doses of radiation, as revealed by immunoblotting studies. As well, a reduction in immunoreactivity was noted when irradiated antigen was used in the ELISA.  相似文献   
3.
Anionic block copolymerization of styrene and divinylbenzene is known to lead to the formation of star-shaped macromolecules. This “arm-first” method has been widely used and studied. The present paper is devoted to two special aspects of this method: The first is concerned with the efficiency of the protection exerted by the arms on the crosslinked core, preventing gelation of the reaction medium. A number of “porcupine” polymers involving bulky cores, fitted with a large number of arms, were synthesized and characterized. The second deals with the possibility of using the “living” carbanionic sites present in the cores, either for purpose of functionalization, or to grow new branches from the core. The presence of remaining unsaturations in the core was evidenced. This is a drawback, since the possibility for “transverse” bonds to be formed results in couplings, inducing gelation.  相似文献   
4.
PurposeTo identify influence of different values of age and abnormal bowel length in HD patients selected for single stage TERPT which affects the technique of surgery.MethodsThis observational study was carried out for over 2.5 years. All children younger than 14 years old with clinical suspicion for HD, typical transitional zone (TZ) on contrast enema (CE) distal to splenic flexure, preoperative diagnosis approved by full thickness biopsy, no previous surgical history and no urgency were included. The distance between the anus and TZ was considered as aganglionic length on CE. Biopsy was taken from distal to proximal of resected bowel to reach circumferentially normal innervated bowel. Paired sample Student's t-test, Pearson correlation test, receiver operating characteristic (ROC) analysis were performed.ResultsForty-eight patients were enrolled in this study. Measured mean for aganglionic bowel length on CE and pathology were 33.5 ± 17.1 cm and 56.8 ± 33.5 cm, respectively (p < 0.01). Correlation coefficient (R) and coefficient of determination (R2) were 0.632 and 40%, respectively (p < 0.01). The difference between radiologic and pathologic measurements in females was higher than males (mean: 29.3 vs 21.9 cm) but was not statistically significant (p = 0.75). There was statistically significant difference between CE and pathologic results in the infants younger than 10 months (p = .004). Abnormal bowel length equal to 52 cm predicted requirement of laparoscopy assistance/laparotomy with 75% sensitivity and 85% specificity.ConclusionOur investigation showed it is safe to attempt for single stage TERPT when aganglionic length on CE is less than 52 cm and the child with HD is older than 10 months. Chance of requiring additional laparotomy or laparoscopy assistance is low in these patients.Type of studyStudy of diagnostic test.Level of evidenceLevel II.  相似文献   
5.
BackgroundFew studies evaluate the impact of unhealthy alcohol and drug use on the risk and severity of postoperative outcomes after upper gastrointestinal and pancreatic oncologic resections.MethodsThe National Inpatient Sample was queried to identify patients undergoing total gastrectomy, esophagectomy, total pancreatectomy, and pancreaticoduodenectomy between 2012 and 2015. Unhealthy alcohol and drug use was assessed by the International Classification of Diseases, Ninth Revision, and National Inpatient Sample coder designation. Multivariable regression was used to identify associations between alcohol and drug use and postoperative complication, duration of stay, hospital cost, and mortality.ResultsIn the study, 59,490 patients met inclusion criteria; 2,060 (3.5%) had unhealthy alcohol use; 1,265 (2.1%) had unhealthy drug use. Postoperative complication rates were higher in patients with alcohol and drug use than in abstainers (67.5% vs 62.8% vs 57.2%; P < .01). On multivariable regression, alcohol use was independently associated with increased risk of a nonwithdrawal complication (odds ratio 1.33 [1.05, 1.68]), and alcohol and drug use were independently associated with increased length of stay (1.54 [0.12, 2.96]) and 2.22 [0.90, 3.55] days) and cost ($5,471 [$60, $10,881] and $4,022 [$402, $7,643]), but not mortality.ConclusionUnhealthy substance use is associated with increased rates of postoperative complications, prolonged length of stay, and costs in patients undergoing major upper gastrointestinal and pancreatic oncologic resections. Screening and abstinence interventions should be incorporated into the preoperative care pathways for these patients.  相似文献   
6.
OBJECT: The authors describe a computer-resident digital representation of a stereotactic atlas of the human brainstem, its semiautomated registration to sagittal fast low-angle shot three-dimensional (3-D) magnetic resonance (MR) imaging data sets in 27 healthy volunteers and 24 neurosurgical patients, and an analysis of the subsequent transforms needed to refine the initial registration. METHODS: Contour drawings from the atlas, which offer the 70th percentile of variation of anatomical structures, were interpolated into an isotropic 3-D representation. Initial atlas-to-patient registration was based on the fastigium/ventricular floor plane reference system. The quality of the fit was evaluated using superimposition of the atlas and MR images. If necessary, the atlas was tailored to the individual anatomy by using additional transforms. On average, the atlas had to be stretched by 2 to 6% in the three directions of space. Scale factors varied over a broad range from -8 to +19% and the benefit of visual interactive control of the atlas-to-patient registration was evident. Analysis of distances within the pons measured in the midsagittal MR imaging slices and the required scale factors revealed significant correlations that may be used to reduce the amount of user interaction in the coregistration substantially. In 70.6% of the cases, the atlas had to be shifted in a cranial direction along the brainstem axis (in 25.5% of cases 3-4 mm, in 45.1% of cases 1-2 mm). This was due to a more caudal position of the fastigium cerebelli on the MR images compared with the atlas. CONCLUSIONS: This observation, in conjunction with the variability of the height of the fourth ventricle in our MR imaging data (range 6.1-15.2 mm, mean 10.1 mm, standard deviation 1.8 mm) calls into question the role of the fastigium cerebelli as an anatomical landmark for localization within the brainstem.  相似文献   
7.
8.
Swyer syndrome is a 46, XY karyotype, with pure gonadal dysgenesis and primary amenorrhea. These females have primordial Mullerian structures and seek medical attention as they experience primary amenorrhea. Here, we report a 15‐year‐old girl, diagnosed as Swyer syndrome associated with left ovarian dysgerminoma.  相似文献   
9.
Development of pemphigus foliaceus (PF) following SARS‐CoV‐2 infection has only been reported in one patient who had received Bamlanivimab and thus might be considered as a drug‐induced case of PF. Here, we reported the first case of PF arising solely after COVID infection without taking any culprit drug.  相似文献   
10.
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