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   2274篇
  免费   131篇
  国内免费   32篇
耳鼻咽喉   30篇
儿科学   69篇
妇产科学   24篇
基础医学   232篇
口腔科学   34篇
临床医学   211篇
内科学   538篇
皮肤病学   117篇
神经病学   109篇
特种医学   237篇
外科学   247篇
综合类   29篇
预防医学   288篇
眼科学   6篇
药学   93篇
中国医学   3篇
肿瘤学   170篇
  2023年   9篇
  2021年   18篇
  2020年   23篇
  2019年   21篇
  2018年   31篇
  2017年   31篇
  2016年   41篇
  2015年   50篇
  2014年   74篇
  2013年   136篇
  2012年   71篇
  2011年   78篇
  2010年   101篇
  2009年   104篇
  2008年   85篇
  2007年   98篇
  2006年   78篇
  2005年   75篇
  2004年   47篇
  2003年   47篇
  2002年   59篇
  2001年   51篇
  2000年   33篇
  1999年   38篇
  1998年   95篇
  1997年   80篇
  1996年   85篇
  1995年   58篇
  1994年   68篇
  1993年   59篇
  1992年   29篇
  1991年   30篇
  1990年   28篇
  1989年   49篇
  1988年   52篇
  1987年   41篇
  1986年   31篇
  1985年   30篇
  1984年   23篇
  1983年   16篇
  1982年   24篇
  1981年   21篇
  1980年   14篇
  1979年   18篇
  1978年   15篇
  1977年   21篇
  1976年   16篇
  1975年   18篇
  1973年   14篇
  1971年   8篇
排序方式: 共有2437条查询结果,搜索用时 109 毫秒
1.
2.
3.
Brain Imaging and Behavior - In healthy participants, the strength of task-evoked network reconfigurations is associated with cognitive performance across several cognitive domains. It is, however,...  相似文献   
4.
5.
The success of vaccination programs is contingent upon irrefutable scientific safety data combined with high rates of public acceptance and population coverage. Vaccine hesitancy, characterized by lack of confidence in vaccination and/or complacency about vaccination that may lead to delay or refusal of vaccination despite the availability of services, threatens to undermine the success of coronavirus disease 2019 (COVID-19) vaccination programs. The rapid pace of vaccine development, misinformation in popular and social media, the polarized sociopolitical environment, and the inherent complexities of large-scale vaccination efforts may undermine vaccination confidence and increase complacency about COVID-19 vaccination. Although the experience of recent lethal surges of COVID-19 infections has underscored the value of COVID-19 vaccines, ensuring population uptake of COVID-19 vaccination will require application of multilevel, evidence-based strategies to influence behavior change and address vaccine hesitancy. Recent survey research evaluating public attitudes in the United States toward the COVID-19 vaccine reveals substantial vaccine hesitancy. Building upon efforts at the policy and community level to ensure population access to COVID-19 vaccination, a strong health care system response is critical to address vaccine hesitancy. Drawing on the evidence base in social, behavioral, communication, and implementation science, we review, summarize, and encourage use of interpersonal, individual-level, and organizational interventions within clinical organizations to address this critical gap and improve population adoption of COVID-19 vaccination.  相似文献   
6.
OBJECTIVES: To compare the relative amounts of elastase (primary polymorphonuclear leucocyte granule constituent) and lactoferrin (secondary PMN granule constituent) in the gingival crevicular fluid (GCF) of healthy, gingivitis and periodontitis sites.
DESIGN: This cross-sectional study looked at the two GCF constituents in three categories of disease status within the same subject.
MATERIALS AND METHODS: Patients with chronic adult periodontitis were screened and those exhibiting all three types of sites ie periodontally healthy, gingivitis and periodontitis sites were recruited (n = 10) and had GCF collected from the three sites. Lactoferrin and elastase were measured in eluates of GCF by enzyme-linked immunosorbent assay.
RESULTS: The absolute amount of lactoferrin measured in ng per 30 s samples was significantly lower in healthy and gingivitis sites as compared to periodontitis sites however this difference failed to reach significance when the concentration of lactoferrin in GCF was used as the analytical unit. No significant differences were found for elastase levels at any sites when expressed as either absolute amounts or concentrations. Secondary granule release, as evidenced by lactoferrin levels, occurs during cell migration and the process is independent of primary granule release, which is thought to correlate with PMN activation. The relationship between granule constituents in the samples showed significant differences, the highest lactoferrinlelastase ratio being at periodontitis sites (P < 0.001).
CONCLUSIONS These findings imply a change in the relative amounts of elastase and lactoferrin released at different disease level sites, with an almost 10-fold increase in the proportion of lactoferrin to elastase in periodontitis sites over healthy and gingivitis sites. This variation in the release by PMNs of primary and secondary granule constituents may indicate alterations in PMN function in different disease environments.  相似文献   
7.
Neuropsychological follow-up appointments are important for patients who have had intracranial surgery because cognitive deficits are common in this population and prognosis is not always optimistic. Unfortunately some patients cancel or do not show up. The current study attempted to identify predictors of non-attendance in this population. A total of 428 patients recruited over 2 years with a scheduled neuropsychological follow-up appointment after intracranial surgery in the St. Elisabeth Hospital, Tilburg, The Netherlands were included. Demographic, clinical, and other miscellaneous variables were extracted from medical records. Of this total population, 42% were non-attenders. The predictors of non-attendance were as follows: patients who had subdural hematomas and/or malignant tumors (compared to those who had other diagnoses prior to intracranial surgery); those who had been transferred to another hospital (compared to those sent home); those who had been referred for further medical treatment before the appointment; a shorter time interval between discharge and follow-up appointment; and finally, if the patient’s home was further away from the hospital. Patients who undergo intracranial surgery are a very heterogeneous group with different needs. Neuropsychological follow-up after surgery may be important for some patients (the better-functioning and/or those with cognitive complaints) but perhaps not for others (those with more severe prognoses and/or no complaints). We provide suggestions which should increase attendance in those who could benefit from follow-up neuropsychological assessment.  相似文献   
8.
α-葡萄糖苷酶抑制剂治疗2型糖尿病的系统评价   总被引:4,自引:0,他引:4  
目的评价α-葡萄糖苷酶抑制剂治疗2型糖尿病患者的效果。方法检索Cochrane图书馆、MEDLINE、EMBASE、CurrentContents、LILACS在研试验数据库,主题为α-葡萄糖苷酶抑制剂的综述的参考文献,并联系纳入试验的专家与实施者。最近检索日期为2003年月12月(CurrentContents)和2003年4月(其他数据库)。纳入α-葡萄糖苷酶抑制剂单一疗法与其它干预比较,治疗2型糖尿病疗程至少12周的随机对照试验,并且试验至少包括以下结局之一:病死率、患病率、生活质量、血糖控制、血脂、胰岛素水平、体重、不良事件。两名评价者独立阅读所有摘要,评价质量并提取数据,分歧通过协商解决或由第三位评价者裁决。由一位统计学家在对提取数据输入数据库时进行检查。我们尽量联系所有作者以核实数据。结果共纳入41个试验、8130例受试者,其中30个针对阿卡波糖,7个针对米格列醇,1个针对优格列波糖,还有3个为不同α-葡萄糖苷酶抑制剂间的比较。绝大多数研究疗程为24周,仅有2个研究超过1年。与安慰剂相比,阿卡波糖血糖控制效果更好:糖化血红蛋白–0.8%[95%CI(–0.9,–0.7)],空腹血糖–1.1mmol/L[95%CI(–1.4,–0.9)],负荷血糖–2.3mmol/L[95%CI(–2.7,–1.9)],阿卡波糖对糖化血红蛋白的作用呈非剂量依赖。我们发现其可降低负荷胰岛素,但对血脂和体重未见临床相关的作用。不良反应主要来自胃肠道且与剂量相关。相对于磺脲,阿卡波糖将空腹和负荷胰岛素水平分别降低至–24.8pmol/L[95%CI(–43.3,–6.3)]和–133.2pmol/L[95%CI(–184.5,–81.8)],但阿卡波糖引起的不良反应更多。结论关于α-葡萄糖苷酶抑制剂是否影响2型糖尿病患者的病死率和患病率仍不清楚。相反,其对血糖控制或胰岛素水平作用明显,对血脂和体重的作用差异无统计学意义。α-葡萄糖苷酶抑制剂更长疗程的效果仍不确定。阿卡波糖剂量超过50mg(TID)时不能进一步影响糖化血红蛋白水平,不良反应反而更多,与磺脲相比,α-葡萄糖苷酶抑制剂降低了空腹和负荷胰岛素水平,但在血糖控制和不良反应方面存在不利影响。  相似文献   
9.
We present an unusual case of haematogenous osteomyelitis in the diaphysis of the tibia of an adult leading to a subacute presentation with an extracortical abscess. Fluid from the abscess grew methicillin resistant Staphylococcus aureus (MRSA) on culture; MRSA with the same antibiogram had been grown from the patient’s blood seven years earlier following a bowel resection. Drainage of the abscess and curettage of the bone lesion together with appropriate antibiotic therapy led to resolution of the osteomyelitis.  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