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   2347篇
  免费   87篇
  国内免费   7篇
耳鼻咽喉   37篇
儿科学   110篇
妇产科学   18篇
基础医学   194篇
口腔科学   36篇
临床医学   152篇
内科学   534篇
皮肤病学   34篇
神经病学   114篇
特种医学   75篇
外科学   491篇
综合类   65篇
预防医学   123篇
眼科学   157篇
药学   129篇
中国医学   9篇
肿瘤学   163篇
  2023年   15篇
  2022年   42篇
  2021年   104篇
  2020年   48篇
  2019年   71篇
  2018年   80篇
  2017年   58篇
  2016年   70篇
  2015年   68篇
  2014年   107篇
  2013年   128篇
  2012年   214篇
  2011年   191篇
  2010年   121篇
  2009年   104篇
  2008年   165篇
  2007年   145篇
  2006年   124篇
  2005年   102篇
  2004年   85篇
  2003年   79篇
  2002年   89篇
  2001年   16篇
  2000年   14篇
  1999年   25篇
  1998年   5篇
  1997年   6篇
  1996年   7篇
  1995年   10篇
  1994年   5篇
  1993年   4篇
  1992年   9篇
  1991年   10篇
  1990年   11篇
  1989年   9篇
  1988年   7篇
  1987年   5篇
  1985年   4篇
  1977年   4篇
  1976年   4篇
  1974年   4篇
  1972年   10篇
  1970年   4篇
  1969年   4篇
  1968年   4篇
  1967年   4篇
  1966年   10篇
  1965年   3篇
  1962年   4篇
  1946年   4篇
排序方式: 共有2441条查询结果,搜索用时 15 毫秒
11.
Peduncular hallucinations are formed visual images often associated with sleep disturbance, and are caused by lesions in the midbrain, pons and diencephalon. In the present study, we report two patients who developed peduncular hallucinations following surgery in the suprasellar region. In one of these, the peduncular hallucinations were a sequel to endoscopic third ventriculostomy, while in the other, they were due to diencephalon and mid-brain compression by a postoperative clot following excision of a hypothalamic astrocytoma.  相似文献   
12.
A case of a child with bilateral fleshy limbal masses with a coloboma of the right upper lid is discussed. Systemic examination revealed two patches of alopecia on the right frontoparietal and right occipital areas of the scalp. Punch biopsy and histopathological examination led to the diagnosis of Linear Nevus Sebaceus Syndrome (LNSS) with bilateral complex limbal choristomas. The authors have stated that they do not have a significant financial interest or other relatioship with any product manufacturer or provider of services discussed in this article. The authors also do not discuss the use of off-label products, which includes unlabeled, unapproved, or investigative products or devices.  相似文献   
13.
OBJECTIVES: To determine whether pulse oximetry-detected episodes of desaturation are associated with impairment of cerebral and somatic (renal) tissue oxygenation in mechanically ventilated preterm neonates. DESIGN: Observational cross-sectional study. SETTING: Neonatal intensive care unit of a university-affiliated children's hospital. PATIENTS: Ten mechanically ventilated preterm (gestational age 24-32 wks) infants. INTERVENTIONS: In addition to the traditional monitoring of hemodynamic variables that included pulse oximetry (Sao2), near-infrared spectroscopy (NIRS) was used to evaluate the cerebral and somatic (renal) tissue oxygen saturation (rSO2C and rSO2R, respectively). MEASUREMENTS AND MAIN RESULTS: A total of 40 rSO2C and rSO2R measurements were simultaneously recorded: 20 during hypoxic events when the Sao2 was /=4 secs (cases) and generally ranged between 70% and 80%, and 20 measurements when the Sao2 was >/=85% (paired controls). Additionally, the fractional oxygen extraction (FOE) from the cerebral (FOEC) and renal (FOER) tissue was calculated. All the measurements were made under steady conditions during a 2-hr period. The rSO2C, rSO2R, FOEC, and FOER among the cases (Sao2 /= 85%) were compared using the paired Student's t-test. Both rSO2C and rSO2R during the desaturation episodes were lower than in the controls (51.6 +/- 6.3% vs. 66.2 +/- 10.2%, p < .0001 and 61.1 +/- 6.8% vs. 80.1 +/- 10.0%, p < .0001, respectively). The FOEC during the hypoxic episodes was comparable with control levels but increased in renal tissue. However, during two of the desaturation episodes (10%), the rSO2C and FOEC levels (which were <44% and >0.47, respectively) may reflect compromised tissue oxygen supply. CONCLUSIONS: In the majority of mechanically ventilated preterm neonates, the reduction in cerebral and renal tissue oxygenation associated with short periods of decreased arterial saturation to 70-80% does not significantly compromise oxygen utilization in the cerebral tissue but increases oxygen extraction in the renal tissue, which might cause ischemic tissue injury following a further reduction in oxygen delivery.  相似文献   
14.
15.
High utilizers of alcohol and other drug treatment (AODTx) services are a priority for healthcare cost control. We examine characteristics of Medicaid-funded AODTx clients, comparing three groups: individuals < 90th percentile of AODTx expenditures (n = 41,054); high-cost clients in the top decile of AODTx expenditures (HC; n = 5,718); and 1760 enrollees in a chronic care management (CM) program for HC clients implemented in 22 counties in New York State. Medicaid and state AODTx registry databases were combined to draw demographic, clinical, social needs and treatment history data. HC clients accounted for 49% of AODTx costs funded by Medicaid. As expected, HC clients had significant social welfare needs, comorbid medical and psychiatric conditions, and use of inpatient services. The CM program was successful in enrolling some high-needs, high-cost clients but faced barriers to reaching the most costly and disengaged individuals.  相似文献   
16.
Retinal pigment epithelial detachment, often asymptomatic is a common retinal finding. Multiple serous retinal pigment epithelial detachment especially in a female is very uncommon. We describe a case of multiple retinal pigment epithelial detachments throughout the fundus in a 51-year old female otherwise asymptomatic. Indocyanine green angiography and fundus auto fluorescence showed abnormalities with a normal systemic work-up. This is the first report of an asymptomatic patient correlating angiogram with auto fluorescence in multiple serous retinal pigment epithelial detachments.  相似文献   
17.
18.
3-Phenoxybenzoic acid (3-PBA) and 4-hydroxy-3-phenoxybenzoic acid (OH-PBA) are the two common metabolites for most pyrethroid insecticides. A rapid, sensitive, and eco-friendly method has been developed based on ultrasound-assisted dispersive liquid–liquid microextraction (DLLME) coupled to large volume injection–gas chromatography–tandem mass spectrometry for the simultaneous determination of pyrethroid metabolites in rat brain treated with cypermethrin (CYP). Brain samples were homogenized in methanol (disperser solvent) followed by derivatization with methyl chloroformate (MCF) and extraction using DLLME. Factors that influence the extraction and derivatization efficiency such as type and volume of extraction and disperser solvent, sonication time, pH, ionic strength, and volumes of MCF and pyridine were optimized. Under optimized conditions, the limits of detection were 1 and 4 ng/g for 3-PBA and OH-PBA, respectively. Mean recoveries of pyrethroid metabolites in rat brain were in the range of 83–95 %. The developed method was successfully applied for determination of 3-PBA and OH-PBA in brain samples of CYP-treated rats. The developed method can be adopted for rapid and sensitive analysis of pyrethroid metabolites in toxicological and forensic laboratories.  相似文献   
19.
We report a case of a newborn male who had mongoloid slant and was hypotonic at birth. Routine investigations revealed leucocytosis (WBC > 70,000/cmm) with 50% blasts in peripheral blood film. Marrow examination confirmed the excess of blasts. Karyotyping revealed 47, XY + 21 chromosomes. Due to absence of clinical symptoms, the baby was kept on follow-up without treatment. Within 7 weeks, PBF and bone marrow findings returned to normal, and the child was diagnosed as having Transient leukaemia with Down syndrome.  相似文献   
20.
The objective of this work was to collect and summarize relevant literature on the anatomy, histology, and imaging of apical support of the upper vagina and the uterus provided by the cardinal (CL) and uterosacral (USL) ligaments. A literature search in English, French, and German languages was carried out with the keywords apical support, cardinal ligament, transverse cervical ligament, Mackenrodt ligament, parametrium, paracervix, retinaculum uteri, web, uterosacral ligament, and sacrouterine ligament in the PubMed database. Other relevant journal and textbook articles were sought by retrieving references cited in previous PubMed articles. Fifty references were examined in peer-reviewed journals and textbooks. The USL extends from the S2 to the S4 vertebra region to the dorsal margin of the uterine cervix and/or to the upper third of the posterior vaginal wall. It has a superficial and deep component. Autonomous nerve fibers are a major constituent of the deep USL. CL is defined as a perivascular sheath with a proximal insertion around the origin of the internal iliac artery and a distal insertion on the cervix and/or vagina. It is divided into a cranial (vascular) and a caudal (neural) portions. Histologically, it contains mainly vessels, with no distinct band of connective tissue. Both the deep USL and the caudal CL are closely related to the inferior hypogastric plexus. USL and CL are visceral ligaments, with mesentery-like structures containing vessels, nerves, connective tissue, and adipose tissue.  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