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   6336篇
  免费   465篇
  国内免费   84篇
耳鼻咽喉   115篇
儿科学   243篇
妇产科学   169篇
基础医学   904篇
口腔科学   126篇
临床医学   777篇
内科学   1395篇
皮肤病学   84篇
神经病学   421篇
特种医学   438篇
外科学   729篇
综合类   149篇
一般理论   1篇
预防医学   503篇
眼科学   45篇
药学   373篇
中国医学   4篇
肿瘤学   409篇
  2023年   29篇
  2022年   45篇
  2021年   73篇
  2020年   42篇
  2019年   97篇
  2018年   117篇
  2017年   95篇
  2016年   96篇
  2015年   116篇
  2014年   136篇
  2013年   239篇
  2012年   274篇
  2011年   276篇
  2010年   211篇
  2009年   166篇
  2008年   262篇
  2007年   296篇
  2006年   261篇
  2005年   258篇
  2004年   226篇
  2003年   232篇
  2002年   225篇
  2001年   173篇
  2000年   176篇
  1999年   158篇
  1998年   155篇
  1997年   136篇
  1996年   154篇
  1995年   129篇
  1994年   139篇
  1993年   112篇
  1992年   129篇
  1991年   139篇
  1990年   111篇
  1989年   122篇
  1988年   135篇
  1987年   114篇
  1986年   124篇
  1985年   105篇
  1984年   64篇
  1983年   69篇
  1982年   54篇
  1981年   47篇
  1980年   47篇
  1979年   69篇
  1978年   58篇
  1977年   29篇
  1976年   46篇
  1975年   29篇
  1974年   33篇
排序方式: 共有6885条查询结果,搜索用时 15 毫秒
991.
Previous published research has shown promising results with flexion splinting post total knee arthroplasty. Before instituting this practice, we conducted a randomised controlled trial to confirm any benefits over splinting in extension. Five patients were recruited into the trial. 5 were excluded. The flexion group consisted of 49 patients who had their knee placed in 70 degrees of flexion over an inactive CPM machine for 24 h post operation. The extension group consisted of 46 patients who were splinted in full extension for the first 24 h post operation. We assessed post-operative day 1 drain volume, haemoglobin and haematocrit, blood transfusions, duration of inpatient stay, range of motion and complications within 6 weeks of surgery. There was no significant difference between the two groups among any of the outcomes measured. As such, we have been unable to demonstrate any benefit with splintage in flexion post total knee arthroplasty and have not adopted it as part of our post-operative management.  相似文献   
992.
BACKGROUND: Fingerstick blood samples are used to estimate donor venous hemoglobin (Hb). STUDY DESIGN AND METHODS: Fingerstick Hb or hematocrit (Hct) was determined routinely for 2425 selected donors at six blood centers, along with venous Hb. Using sex and measures of iron status including absent iron stores (AIS; ferritin < 12 ng/mL), linear regression models were developed to predict venous Hb from fingerstick. RESULTS: Across all subjects, fingerstick Hb was higher than venous Hb in the higher part of the clinical range, but lower in the lower part of the range. The relationship varied by sex and iron status. Across centers, a female donor had on average a venous Hb result 0.5 to 0.8 g/dL lower than a male donor with the same fingerstick Hb and iron status. Similarly, a donor with AIS had on average a venous Hb result 0.3 to 1.1 g/dL lower than an iron‐replete donor with the same fingerstick value and sex. An iron‐replete male donor with a fingerstick result at the cutoff (Hb 12.5 g/dL) had an acceptable expected venous Hb (12.8 to 13.8 g/dL). A female donor with AIS with a fingerstick result at the cutoff had an expected venous Hb below 12.5 g/dL (11.7 to 12.4 g/dL). Of females with AIS, 40.2% donated blood when their venous Hb was less than 12.5 g/dL. CONCLUSIONS: Fingerstick is considered a useful estimator of venous Hb. However, in some donor groups, particularly female donors with AIS, fingerstick overestimates venous Hb at the donation cutoff. This significant limitation should be considered in setting donor fingerstick Hb or Hct requirements.  相似文献   
993.
Satratoxin-G (SG) is a trichothecene mycotoxin of Stachybotrys chartarum, the black mold suggested to contribute etiologically to illnesses associated with water-damaged buildings. We have reported that intranasal exposure to SG evokes apoptosis of olfactory sensory neurons (OSNs) and acute inflammation in the nose and brain of laboratory mice. To further assess the potential human risk of nasal airway injury and neurotoxicity, we developed a model of SG exposure in monkeys, whose nasal airways more closely resemble those of humans. Adult, male rhesus macaques received a single intranasal instillation of 20 μg SG (high dose, n = 3), or 5 μg SG daily for four days (repeated low dose, n = 3) in one nasal passage, and saline vehicle in the contralateral nasal passage. Nasal tissues were examined using light and electron microscopy and morphometric analysis. SG induced acute rhinitis, atrophy of the olfactory epithelium (OE), and apoptosis of OSNs in both groups. High-dose and repeated low-dose SG elicited a 13% and 66% reduction in OSN volume density, and a 14-fold and 24-fold increase in apoptotic cells of the OE, respectively. This model provides new insight into the potential risk of nasal airway injury and neurotoxicity caused by exposure to water-damaged buildings.  相似文献   
994.

Purpose

This study aimed to determine the proportion and characteristics of radiation oncology outpatients who were willing to answer questions about their life expectancy.

Methods

A cross-sectional patient self-report survey was conducted using touch screen computers in Australian radiation oncology treatment centers. The primary outcome was the respondent’s willingness to complete a survey subsection about life expectancy. Demographic and disease characteristics were also collected, and level of anxiety and depression was assessed using the Hospital Anxiety and Depression Scale.

Results

Of the 469 oncology outpatients who completed the survey, 327 (70?%; 95?% CI, 65?%, 74?%) indicated that they were willing to answer questions about life expectancy. Being female (p?<?0.001), older (p?<?0.05), born in Asia (p?<?0.05), and being diagnosed with cancer types other than breast and prostate cancer (p?<?0.01) were associated with lower odds of answering life expectancy questions.

Conclusions

The opportunity to opt-out of survey questions about sensitive issues such as life expectancy is a feasible method for accessing important information about patient preferences while minimizing burden. Further research may be needed to improve acceptability of life expectancy research to some patient groups.  相似文献   
995.
996.
997.
998.
HIV-Tat protein has been implicated in the pathogenesis of HIV-1 neurological complications (i.e., neuroAIDS), but direct demonstrations of the effects of Tat on behavior are limited. GT-tg mice with a doxycycline (Dox)-inducible and brain-selective tat gene coding for Tat protein were used to test the hypothesis that the activity of Tat in brain is sufficient to impair learning and memory processes. Western blot analysis of GT-tg mouse brains demonstrated an increase in Tat antibody labeling that seemed to be dependent on the dose and duration of Dox pretreatment. Dox-treated GT-tg mice tested in the Barnes maze demonstrated longer latencies to find an escape hole and displayed deficits in probe trial performance versus uninduced GT-tg littermates, suggesting Tat-induced impairments of spatial learning and memory. Reversal learning was also impaired in Tat-induced mice. Tat-induced mice additionally demonstrated long-lasting (up to one month) deficiencies in novel object recognition learning and memory performance. Furthermore, novel object recognition impairment was dependent on the dose and duration of Dox exposure, suggesting that Tat exposure progressively mediated deficits. These experiments provide evidence that Tat protein expression is sufficient to mediate cognitive abnormalities seen in HIV-infected individuals. Moreover, the genetically engineered GT-tg mouse may be useful for improving our understanding of the neurological underpinnings of neuroAIDS-related behaviors.  相似文献   
999.

Purpose

Psychological problems could lead to several adverse health outcomes and were strongly correlated with cigarette smoking and alcohol consumption. In addition, patients treated in EDs were vulnerable to psychological problems. We therefore examined the population-level association between serious psychological distress (SPD) and emergency department (ED) use among young adults in the USA. We also studied the additive effects of SPD, cigarette smoking, and alcohol consumption on the ED presentation.

Methods

The study sample contains 16,873 individuals, using data from the National Health Interview Survey, from 2004 to 2006. Bivariate analyses with chi-square tests and logistic regression analyses are performed.

Results

Young adults having SPD were 2.05 times more likely to go to an ED. People having SPD and being a current smoker were 2.52 times more likely to use services in an ED. However, people having SPD and being a heavy drinker did not have a significantly elevated risk of ED use.

Conclusion

An association between SPD and ED use among US young adults is established in this study. Attempts to decrease excess ED use and the development of strategies to improve mental health among young adults are needed to improve patient health and reduce the health-care burden of high costs and deteriorating ED care quality.  相似文献   
1000.
Assessing joint disorders has been a relatively recent and evolving application of 18F-2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) imaging. FDG is taken up by inflammatory cells, particularly when they are active as part of an ongoing inflammatory process. Hence FDG PET has been employed to assess a wide array of arthritic disorders. FDG PET imaging has been investigated in various joint diseases for diagnostic purposes, treatment monitoring, and as a prognostic indicator as in other disorders. In some of the diseases the ancillary findings in FDG PET have provided important clues about the underlying pathophysiology and pathogenesis processes. While substantial promise has been demonstrated in a number of studies, it is clear that the potential utility of PET in this clinical realm far outweighs that which has been established to date.  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