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   5622篇
  免费   463篇
  国内免费   48篇
耳鼻咽喉   31篇
儿科学   191篇
妇产科学   115篇
基础医学   711篇
口腔科学   85篇
临床医学   661篇
内科学   1080篇
皮肤病学   60篇
神经病学   471篇
特种医学   405篇
外科学   757篇
综合类   116篇
一般理论   4篇
预防医学   605篇
眼科学   76篇
药学   415篇
中国医学   4篇
肿瘤学   346篇
  2021年   61篇
  2020年   53篇
  2019年   54篇
  2018年   75篇
  2017年   85篇
  2016年   61篇
  2015年   100篇
  2014年   151篇
  2013年   196篇
  2012年   231篇
  2011年   233篇
  2010年   189篇
  2009年   158篇
  2008年   207篇
  2007年   258篇
  2006年   207篇
  2005年   205篇
  2004年   228篇
  2003年   222篇
  2002年   233篇
  2001年   216篇
  2000年   208篇
  1999年   153篇
  1998年   97篇
  1997年   99篇
  1996年   78篇
  1995年   85篇
  1994年   65篇
  1993年   91篇
  1992年   103篇
  1991年   129篇
  1990年   124篇
  1989年   134篇
  1988年   119篇
  1987年   112篇
  1986年   102篇
  1985年   103篇
  1984年   78篇
  1983年   81篇
  1982年   55篇
  1981年   42篇
  1980年   46篇
  1979年   59篇
  1978年   57篇
  1977年   37篇
  1976年   32篇
  1975年   37篇
  1974年   34篇
  1973年   31篇
  1972年   35篇
排序方式: 共有6133条查询结果,搜索用时 15 毫秒
91.
To detect cytomegalovirus (CMV) infections, a total of 1,074 cultures of urine, saliva, or blood were collected weekly from 43 consecutive patients undergoing allogeneic bone marrow transplantation. Twenty-three patients were seronegative before transplant and primary infection occurred in 2 (9%). Twenty patients were initially seropositive and recurrent infections occurred in 5 (25%). Three patients in the recurrent group had proven CMV pneumonitis; viraemia was detected in two recipients, while the third had CMV isolated only from bronchial lavage fluid. The serological response of the 43 patients was defined by testing 559 serial sera for specific IgG and IgM antibodies by radioimmunoassay. Passive acquisition of IgG antibodies from blood products was found in 78% of initially seronegative recipients. One patient with primary infection responded in a pattern typical of immunocompetent individuals with long-term production of specific IgG and transient production of specific IgM antibodies. The second patient also had a typical response, but this was delayed until several weeks after the start of virus excretion. In patients with recurrent infections, specific IgM production did not correlate with episodes of virus excretion. Three of five such patients failed to mount a specific IgM response, and these were the only patients in the study to develop CMV pneumonitis. We conclude that CMV infection in bone marrow recipients can only be diagnosed by detection of virus; therefore, the ability of these patients to mount humoral immune responses should not be relied upon for diagnostic purposes.  相似文献   
92.
Papilloedema is not always an adequate predictor of potential complications from lumbar puncture, and many clinicians are using computed tomography (CT) before lumbar puncture in an effort to identify more accurately the "at risk" patient. This paper identifies the following anatomical criteria defined by CT scanning that correlate with unequal pressures between intracranial compartments and predispose a patient to herniation following decompression of the spinal compartment: lateral shift of midline structures, loss of the suprachiasmatic and basilar cisterns, obliteration of the fourth ventricle, or obliteration of the superior cerebellar and quadrigeminal plate cisterns with sparing of the ambient cisterns. These criteria should be considered to be contraindications to lumbar puncture.  相似文献   
93.
Computed tomographic (CT) examinations were performed in seven patients after cochlear implant surgery. Preimplantation CT demonstrated the petrous anatomy well and revealed an abnormality in one case. Postimplantation CT adequately assessed electrode position in all cases. Malposition of the active electrode was identified in one patient. Electrode position was correlated with postimplantation audiometric testing. A "transpetrous" projection was used to image perpendicular to the active electrode within the basal turn of the cochlea. A potential pitfall was identified where the ground electrode tip appeared to be embedded in the carotid canal cortex due to partial-volume averaging. With further experience, the clinical utility of CT in cochlear implantation patients will be better defined.  相似文献   
94.
BackgroundWe aimed to examine process and outcome indicators for adolescents with specific injury patterns managed in pediatric versus adult paradigms within the same trauma system.MethodsAdolescents (15–17 years old) admitted to the region's adult trauma center (ATC) or pediatric trauma center (PTC) with an abdominal injury, femur fracture or traumatic brain injury (TBI) were reviewed retrospectively. Global and injury-specific process and outcome indicators were compared.ResultsOf 141 ATC and 69 PTC patients, injury patterns differed significantly with more TBI and abdominal injuries at the ATC and femur fractures at the PTC. Overall injury severity was greater at the ATC. Patients with solid organ injuries appeared more likely to undergo embolization or splenectomy at the ATC; however, higher injury grade and later time period were the only variables significantly associated with this. Computed tomography (CT) was used significantly more frequently at the ATC overall, most notable with panscanning and head CTs for major TBI. Time to operative management did not differ for patients with isolated femur fractures. Neuropsychological follow up after minor TBI was documented more often at the PTC than the ATC; there was no difference for those with more severe TBIs.ConclusionsManagement varies for adolescents between PTCs and ATCs with more exposure to radiation and less neuropsychological follow-up of less severe TBIs at the ATC. This presents distinct opportunities to identify best policies for triage and sharing of management practices within a single regional inclusive trauma system in order to optimize short and long-term outcomes for this population.Type of studyRetrospective cohort.Level of evidenceLevel IV.  相似文献   
95.
BackgroundPancreatoduodenectomies at high risk for clinically relevant pancreatic fistula are uncommon, yet intimidating, situations. In such scenarios, the impact of individual surgeon experience on outcomes is poorly understood.MethodsThe fistula risk score was applied to identify high-risk patients (fistula risk score 7–10) from 7,706 pancreatoduodenectomies performed at 18 international institutions (2003–2020). For each case, surgeon pancreatoduodenectomy career volume and years of practice were linked to intraoperative fistula mitigation strategy adoption and outcomes. Consequently, best operative approaches for clinically relevant pancreatic fistula prevention and best performer profiles were identified through multivariable analysis models.ResultsEight hundred and thirty high-risk pancreatoduodenectomies, performed by 64 surgeons, displayed an overall clinically relevant pancreatic fistula rate of 33.7%. Clinically relevant pancreatic fistula rates decreased with escalating surgeon career pancreatoduodenectomy (–49.7%) and career length (–41.2%; both P < .001), as did transfusion and reoperation rates, postoperative morbidity index, and duration of stay. Great experience (≥400 pancreatoduodenectomies performed or ≥21-year-long career) was a significant predictor of clinically relevant pancreatic fistula prevention (odds ratio 0.52, 95% confidence interval 0.35–0.76) and was more often associated with pancreatojejunostomy reconstruction and prophylactic octreotide omission, which were both independently associated with clinically relevant pancreatic fistula reduction. A risk-adjusted performance analysis also correlated with experience. Moreover, minimizing blood loss (≤400 mL) significantly contributed to clinically relevant pancreatic fistula prevention (odds ratio 0.40, 95% confidence interval 0.22–0.74).ConclusionSurgeon experience is a key contributor to achieve better outcomes after high-risk pancreatoduodenectomy. Surgeons can improve their performance in these challenging situations by employing pancreatojejunostomy reconstruction, omitting prophylactic octreotide, and minimizing blood loss.  相似文献   
96.
97.
BackgroundAdherent perinephric fat (APF) contributes to surgical complexity and can be associated with adverse perioperative outcomes for partial nephrectomy (PN). The Mayo Adhesive Probability (MAP) score accurately predicts the presence of APF during robotic-assisted partial nephrectomy (RAPN). Our primary aim is to validate MAP score as a predictor of APF in open partial nephrectomy (OPNx).MethodsWe reviewed 105 consecutive OPNx (100 patients) performed by a single surgeon with intraoperative determination of APF. We evaluated the ability of the MAP score to discriminate between those with APF and those without APF by estimating the area under the receiver operating characteristic curve (AUROCC). The association of perioperative outcomes with APF was evaluated as well.ResultsForty-three patients [49%; 95% confidence interval (CI), 39–59%] had intraoperative identification of APF. The MAP score had excellent ability to predict APF in OPNx (AUROCC, 0.82; 95% CI, 0.74–0.92). APF was observed in 6% of patients with a MAP score of 0-1, 27% with score 2, 52% with score 3, 75% with score 4, and 90% with score 5. The presence of APF was associated with longer operative times (P=0.004) and higher estimated blood loss (EBL) (P=0.003). Although not statistically significant, our study did suggest that APF may be associated with postoperative complications and prolonged length of stay (LOS) (>3 days).ConclusionsMAP score accurately predicts the presence of APF in patients undergoing OPNx. APF is associated with longer operative time and higher blood loss in OPNx.  相似文献   
98.
Digital health is transforming the delivery of health care around the world to meet the growing challenges presented by ageing populations with multiple chronic conditions. Digital health technologies can support the delivery of personalised nutrition care through the standardised Nutrition Care Process (NCP) by using personal data and technology‐supported delivery modalities. The digital disruption of traditional dietetic services is occurring worldwide, supporting responsive and high‐quality nutrition care. These disruptive technologies include integrated electronic and personal health records, mobile apps, wearables, artificial intelligence and machine learning, conversation agents, chatbots, and social robots. Here, we outline how digital health is disrupting the traditional model of nutrition care delivery and outline the potential for dietitians to not only embrace digital disruption, but also take ownership in shaping it, aiming to enhance patient care. An overview is provided of digital health concepts and disruptive technologies according to the four steps in the NCP: nutrition assessment, diagnosis, intervention, and monitoring and evaluation. It is imperative that dietitians stay abreast of these technological developments and be the leaders of the disruption, not simply subject to it. By doing so, dietitians now, as well as in the future, will maximise their impact and continue to champion evidence‐based nutrition practice.  相似文献   
99.
100.
The personality structure of 'normal' volunteers   总被引:1,自引:0,他引:1       下载免费PDF全文
The personality structure of 65 volunteers for a Phase 1 drug trial was examined using the Eysenck Personality Questionnaire. It revealed a common pattern of high extroversion, low neuroticism and psychoticism. The reasons why the study might attract such people are examined and the structure compared with those that take drugs that might have 'strange or dangerous effects'. The likely forms of bias that this personality structure may bring to the trial are explored.  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