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   1898篇
  免费   105篇
  国内免费   37篇
耳鼻咽喉   12篇
儿科学   57篇
妇产科学   38篇
基础医学   265篇
口腔科学   27篇
临床医学   248篇
内科学   299篇
皮肤病学   20篇
神经病学   113篇
特种医学   135篇
外科学   235篇
综合类   25篇
一般理论   1篇
预防医学   124篇
眼科学   75篇
药学   170篇
中国医学   9篇
肿瘤学   187篇
  2023年   18篇
  2022年   34篇
  2021年   81篇
  2020年   42篇
  2019年   49篇
  2018年   63篇
  2017年   49篇
  2016年   45篇
  2015年   48篇
  2014年   72篇
  2013年   108篇
  2012年   124篇
  2011年   118篇
  2010年   74篇
  2009年   72篇
  2008年   82篇
  2007年   120篇
  2006年   92篇
  2005年   89篇
  2004年   76篇
  2003年   70篇
  2002年   55篇
  2001年   56篇
  2000年   40篇
  1999年   48篇
  1998年   25篇
  1997年   29篇
  1996年   20篇
  1995年   20篇
  1994年   16篇
  1993年   7篇
  1992年   29篇
  1991年   19篇
  1990年   18篇
  1989年   19篇
  1988年   26篇
  1987年   13篇
  1986年   15篇
  1985年   6篇
  1984年   8篇
  1983年   11篇
  1982年   9篇
  1981年   3篇
  1980年   5篇
  1979年   2篇
  1977年   2篇
  1976年   2篇
  1975年   3篇
  1974年   3篇
  1968年   2篇
排序方式: 共有2040条查询结果,搜索用时 687 毫秒
101.
Objective: To examine the relationship between reflection, gender, residency choice, word count, and academic achievement among medical students.

Methods: A modified version of the Reflection Evaluation for Learners’ Enhanced Competencies Tool (REFLECT) was developed and used for this study (Cronbach’s alpha of 0.86 with an intraclass correlation coefficient [ICC] of 0.68). This was applied to writing samples about professionalism in gross anatomy from first-year medical students between 2005 and 2011. Four analysts reviewed and scored written reflections independently. Composite reflection scores were compared with gender, residency choice, length of written reflection, NBME® Gross Anatomy and Embryology Subject Examination scores, and final gross anatomy course.

Results: Total of 319 written reflections were evaluated. Female students who pursued medicine specialties had the highest composite reflection scores (87 [27.2%]). Word count frequently correlated with reflection score (p?<?0.0001). Students who performed well on the NBME® Gross Anatomy and Embryology Subject Examination tended to achieve high anatomy course grades (p?<?0.0001). There was no statistically significant relationship between composite reflection scores and NBME® Gross Anatomy and Embryology Subject Examination scores (p?=?0.16) or anatomy course grades (p?=?0.90).

Conclusions: This study suggests there are likely no correlations between reflective capacity and academic performance on tests of medical knowledge administered early in the medical curriculum.  相似文献   
102.
红细胞输注前的质量标准   总被引:1,自引:0,他引:1  
现行红细胞输注规则主要规定红细胞采集量和输注时存活红细胞的比例,即450ml的采集量,输注时24h平均体内的存活率至少75%。其他还限制了游离血红蛋白的含量,通常不超过红细胞总量的1.0%。特殊需求的红细胞产品又有额外的要求。每单位少白细胞的红细胞的残余白细胞不超过1×10~6。  相似文献   
103.
BackgroundCancer of unknown primary (CUP) comprises a heterogeneous collection of malignancies that are typically associated with a poor prognosis and a lack of effective treatment options. We retrospectively evaluated the clinical utility of targeted next-generation sequencing (NGS) among CUP patients to assist with diagnosis and identify opportunities for molecularly guided therapy.Patients and MethodsPatients with a CUP at Moffitt Cancer Center who underwent NGS between January 1, 2014 and December 31, 2019, were eligible for study inclusion. Next-generation sequencing results were assessed to determine the frequency of clinically actionable molecular alterations, and chart reviews were performed to ascertain the number of patients receiving molecularly guided therapy.ResultsNinety-five CUP patients were identified for analysis. Next-generation sequencing testing identified options for molecularly guided therapy for 55% (n = 52) of patients. Among patients with molecularly guided therapy options, 33% (n = 17) were prescribed a molecularly guided therapy. The median overall survival for those receiving molecularly guided therapy was 23.6 months. Among the evaluable patients, the median duration of treatment for CUP patients (n = 7) receiving molecular-guided therapy as a first-line therapy was 39 weeks. The median duration of treatment for CUP patients (n = 8) treated with molecularly guided therapy in the second- or later-line setting was 13 weeks. Next-generation sequencing results were found to be suggestive of a likely primary tumor type for 15% (n = 14) of patients.ConclusionNext-generation sequencing results enabled the identification of treatment options in a majority of patients and assisted with the identification of a likely primary tumor type in a clinically meaningful subset of patients.  相似文献   
104.
Lactococcus lactis strain Plasma (LC-Plasma) is reported to have anti-viral effects via direct activation of plasmacytoid dendritic cells, which upregulate the production of type I and III interferons. A randomized, placebo-controlled, double-blind, parallel group study was designed for elementary schoolchildren, grades 1 to 3, in Vietnam. LC-Plasma or a control were administered to schoolchildren as a beverage (1.0 × 1011 count LC-Plasma/day/person). The primary endpoint was to determine the efficacy of LC-Plasma in reducing the cumulative days absent from school due to upper respiratory disease (URID) and gastrointestinal disease (GID), and the secondary endpoint was to evaluate the potency of LC-Plasma on URID/GID symptoms and general well-being scores. LC-Plasma intake significantly reduced the cumulative days absent from school due to URID/GID (Odds ratio (OR) = 0.57, p = 0.004) and URID alone (OR = 0.56, p = 0.005); LC-Plasma also significantly reduced the number of cumulative fever positive days during the first 4 weeks of intervention (OR = 0.58, p = 0.001) and cumulative days with diarrhea during the last 4 weeks of the intervention period (OR = 0.78, p = 0.01). The number of positive general wellbeing days was significantly improved in the LC-Plasma group compared with the control throughout the intervention period (OR = 0.93, 0.93, p = 0.03, 0.04 in the first and last 4 weeks of the intervention, respectively). These data suggest that LC-Plasma seems to improve the health condition of elementary schoolchildren and reduces school absenteeism due to infectious disease, especially URID.  相似文献   
105.
Pramipexole (PPX) is known in the treatment of Parkinson''s disease and restless legs syndrome. We carried out a theoretical investigation on pramipexole–Au cluster interactions for the applications of drug delivery and detection. Three AuN clusters with sizes N = 6, 8 and 20 were used as reactant models to simulate the metallic nanostructured surfaces. Quantum chemical computations were performed in both gas phase and aqueous environments using density functional theory (DFT) with the PBE functional and the cc-pVDZ-PP/cc-pVTZ basis set. The PPX drug is mainly adsorbed on gold clusters via its nitrogen atom of the thiazole ring with binding energies of ca. −22 to −28 kcal mol−1 in vacuum and ca. −18 to −24 kcal mol−1 in aqueous solution. In addition to such Au–N covalent bonding, the metal–drug interactions are further stabilized by electrostatic effects, namely hydrogen-bond NH⋯Au contributions. Surface-enhanced Raman scattering (SERS) of PPX adsorbed on the Au surfaces and its desorption process were also examined. In comparison to Au8, both Au6 and Au20 clusters undergo a shorter recovery time and a larger change of energy gap, being possibly conducive to electrical conversion, thus signaling for detection of the drug. A chemical enhancement mechanism for SERS procedure was again established in view of the formation of nonconventional hydrogen interactions Au⋯H–N. The binding of PPX to a gold cluster is expected to be reversible and triggered by the presence of cysteine residues in protein matrices or lower-shifted alteration of environment pH. These findings would encourage either further theoretical probes to reach more accurate views on the efficiency of pramipexole–Au interactions, or experimental attempts to build appropriate gold nanostructures for practical trials, harnessing their potentiality for applications.

Gold clusters as prospective carriers and detectors of pramipexole.  相似文献   
106.
107.
激光生物效应及医学应用研究   总被引:1,自引:0,他引:1  
李海涛  杨继庆 《医学争鸣》2007,28(14):1341-1342
激光作用于生物体会产生物理、化学或生物学的效应,激光正是通过这些效应达到医学基础研究、诊断和治疗疾病的目的.本文简介了激光与生物组织相互作用所产生的生物效应,概述了激光生物效应在生物学和医学研究中的应用.  相似文献   
108.
The aim of this study was to determine factors that predict mortality in patients with traumatic inferior vena cava (IVC) injuries and to review the current management of this lethal injury. A 7-year retrospective review of all trauma patients with IVC injuries was performed. Factors associated with mortality were assessed by univariate analysis. Significant variables were included in a multivariate regression analysis model to determine independent predictors of mortality. Statistical significance was determined at P < or = 0.05. A literature review of traumatic IVC injuries was performed and compared with our institutional experience. Thirty-six IVC injuries were identified (mortality, 56%; mechanisms of injury, 28% blunt and 72% penetrating). There was no difference in mortality based on mechanism of injury. Injuries with closer proximity to the heart were associated with increased mortality (P < 0.001). Univariate analysis demonstrated that nonsurvivors had a higher injury severity scale, a lower systolic blood pressure in the emergency department, a lower Glasgow coma score (GCS), and were more likely to have thoracotomies performed in the emergency department or operating room. Multivariate analysis revealed that only GCS (P = 0.03) was an independent predictor of mortality. Typical factors predicting mortality were identified in our cohort of patients, including GCS. The mechanism of injury is not associated with survival outcome, although mortality is higher with injuries more proximal to the heart. The form of management by IVC level is reviewed in our patient population and compared with the literature.  相似文献   
109.
Magnetic resonance imaging (MRI) is now a leading diagnostic technique. As technology has improved, so has the spatial resolution achievable. In 1986 MR microscopy (MRM) was demonstrated with resolutions in the tens of micrometers, and is now an established subset of MRI with broad utility in biological and non-biological applications. To date, only large cells from plants or aquatic animals have been imaged with MRM limiting its applicability. Using newly developed microsurface coils and an improved slice preparation technique for correlative histology, we report here for the first time direct visualization of single neurons in the mammalian central nervous system (CNS) using native MR signal at a resolution of 4–8 μm. Thus MRM has matured into a viable complementary cellular imaging technique in mammalian tissues.  相似文献   
110.
Urinary ascites is a rare diagnosis, commonly associated with bladder rupture. We present a case of intraperitoneal bladder injury following a Cesarean section with subsequent development of urinary ascites. Initial laboratory data with elevated serum creatinine and blood urea nitrogen (BUN) raised the suspicion for acute kidney injury due to the recent obstetrical procedure. This case highlights the importance of including intraperitoneal bladder injury with urinary ascites as a key differential in the workup of acute renal failure, particularly in the obstetric surgical setting. The rapid development of ascites with elevated serum BUN and creatinine should prompt work up for evaluating intraperitoneal bladder injury. Early diagnosis and treatment can yield gratifying results and avoid unnecessary workup of other causes of renal failure.  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