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   3421篇
  免费   204篇
  国内免费   11篇
耳鼻咽喉   33篇
儿科学   100篇
妇产科学   82篇
基础医学   442篇
口腔科学   255篇
临床医学   294篇
内科学   741篇
皮肤病学   123篇
神经病学   304篇
特种医学   87篇
外科学   372篇
综合类   29篇
一般理论   3篇
预防医学   237篇
眼科学   100篇
药学   185篇
中国医学   3篇
肿瘤学   246篇
  2023年   32篇
  2022年   38篇
  2021年   96篇
  2020年   60篇
  2019年   86篇
  2018年   78篇
  2017年   63篇
  2016年   85篇
  2015年   89篇
  2014年   108篇
  2013年   147篇
  2012年   236篇
  2011年   256篇
  2010年   155篇
  2009年   122篇
  2008年   207篇
  2007年   242篇
  2006年   230篇
  2005年   238篇
  2004年   202篇
  2003年   169篇
  2002年   170篇
  2001年   35篇
  2000年   22篇
  1999年   26篇
  1998年   37篇
  1997年   48篇
  1996年   23篇
  1995年   15篇
  1994年   39篇
  1993年   25篇
  1992年   8篇
  1991年   10篇
  1990年   12篇
  1989年   15篇
  1988年   18篇
  1987年   11篇
  1986年   11篇
  1985年   12篇
  1984年   20篇
  1983年   12篇
  1982年   13篇
  1981年   14篇
  1980年   9篇
  1978年   12篇
  1977年   10篇
  1976年   6篇
  1969年   6篇
  1962年   6篇
  1961年   6篇
排序方式: 共有3636条查询结果,搜索用时 15 毫秒
101.
102.
This article reports two discoveries. (1) 2-Methoxyethanol induces unprecedented selectivity for etherification of 5-hydroxy-2-nitrobenzic acids without forming undesired esters. (2) Such compounds are precursors for amides showing unusual robustness against oxidative degradation, essential for molecular electrets that transfer strongly oxidizing holes at about −6.4 eV vs. vacuum.

Selective etherification produces precursors for amides resistant to oxidative degradation, i.e., showing reversible oxidation at 1.5 to 1.7 V vs. SCE.  相似文献   
103.
104.
We have benefited from using a simple, time-saving radiographic procedure for more than 5 years which may establish a correct diagnosis in most patients with clinically suspected, but initially occult, hip fractures.  相似文献   
105.
106.
It is important to estimate both chronological age (CA) and maturational age of an individual, in order to perform orthopedic treatment or surgery, and in cases of lost documentation. Use of dental age (DA) for these purposes has been widely studied; however, the literature is scarce with regard to individuals with Down syndrome (DS), a prevalent condition worldwide. In this study the chronology of dental maturation was evaluated by analyzing the DA of individuals with DS based on the Chronological Mineralization Table proposed by Nolla (1960). Thus, second molars were evaluated in 57 panoramic radiographs of male and female individuals with DS, between 5 and 16 years-old. These data were compared with a control group of 191 nonsyndromic individuals of the same age group. Correlation between CA and DA was ascertained using Pearson's correlation coefficient (r), and the difference between these variables was measured using Student's t-test for paired samples and the method proposed by Bland and Altman. The difference between DA and CA was compared between the control and DS groups using Student's t-test for independent samples (α = 0.05). DA was slightly lower than the CA; however, this difference was only significant for females. The difference between DA and CA was not significant between individuals with DS and control group (both genders, p = 0.945; males, p = 0.542; females, p = 0.381). We concluded that dental maturation in individuals with DS occurs similarly to that of nonsyndromic individuals.  相似文献   
107.
108.
ObjectiveSpinal cord stimulation (SCS) has become a popular nonopioid pain intervention. However, the treatment failure rate for SCS remains significantly high and many of these patients have poor sagittal spinopelvic balance, which has been found to correlate with increased pain and decreased quality of life. The purpose of this study was to determine if poor sagittal alignment is correlated with SCS treatment failure.Materials and MethodsComparative retrospective analysis was performed between two cohorts of patients who had undergone SCS placement, those who had either subsequent removal of their SCS system (representing a treatment failure cohort) and those that underwent generator replacement (representing a successful treatment cohort). The electronic medical record was used to collect demographic and surgical characteristics, which included radiographic measurements of lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS). Also included were data on pain medication usage including opioid and nonopioid therapies.ResultsEighty-one patients met inclusion criteria, 31 had complete removal, and 50 had generator replacements. Measurement of sagittal balance parameters demonstrated that many patients had poor alignment, with 34 outside normal range for LL (10 vs 24 in removal and replacement cohorts, respectively), 30 for PI (12 [38.7%] vs 18 [36.0%]), 46 for PT (18 [58.1%] vs 28 [56.0%]), 38 for SS (18 [58.1%] vs 20 [40.0%]), and 39 for PI-LL mismatch (14 [45.2%] vs 25 [50.0%]). There were no significant differences in sagittal alignment parameters between the two cohorts.ConclusionsThis retrospective cohort analysis of SCS patients did not demonstrate any relationship between poor sagittal alignment and failure of SCS therapy. Further studies of larger databases should be performed to determine how many patients ultimately go on to have additional structural spinal surgery after failure of SCS and whether or not those patients go on to have positive outcomes.  相似文献   
109.
Anaphylaxis in the pediatric population is both serious and potentially lethal. The incidence of allergic and anaphylactic reactions has been increasing and the need for life saving intervention with epinephrine must remain an important part of Emergency Medical Services (EMS) provider training. Our aim was to characterize dosing and timing of epinephrine, diphenhydramine, and albuterol in the pediatric patient with anaphylaxis. In this retrospective chart review, we studied prehospital medication administration in pediatric patients ages 1 month up to 14 years old classified as having a severe allergic reaction or anaphylaxis. We compared rates of epinephrine, diphenhydramine, and albuterol given to patients with allergic conditions including anaphylaxis. In addition, we calculated the rate of epinephrine administration in cases of anaphylaxis and determined what percentage of time the epinephrine was given by EMS or prior to their arrival. Of the pediatric patient contacts, 205 were treated for allergic complaints. Of those with allergic complaints, 98 of 205 (48%; 95% CI 41%, 55%) had symptoms consistent with anaphylaxis and indications for epinephrine. Of these 98, 53 (54%, 95% CI 44%, 64%) were given epinephrine by EMS or prior to EMS arrival. Among the patients in anaphylaxis not given epinephrine prior to EMS arrival, 6 (12%; 95% CI 3%, 21%) received epinephrine from EMS, 10 (20%; 95% CI 9%, 30%) received diphenhydramine only, 9 (18%, 95% CI 7%–28%) received only albuterol and 17 (33%, 95% CI 20%–46%) received both albuterol and diphenhydramine. 9 patients in anaphylaxis received no treatment prior to arriving to the emergency department (18%, 95% CI 7%–28%). In pediatric patients who met criteria for anaphylaxis and the use of epinephrine, only 54% received epinephrine and the overwhelming majority received it prior to EMS arrival. EMS personnel may not be treating anaphylaxis appropriately with epinephrine.  相似文献   
110.
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