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   168620篇
  免费   32186篇
  国内免费   2411篇
耳鼻咽喉   5318篇
儿科学   6029篇
妇产科学   2958篇
基础医学   5346篇
口腔科学   1631篇
临床医学   30231篇
内科学   50024篇
皮肤病学   7749篇
神经病学   16337篇
特种医学   6589篇
外科学   42303篇
综合类   389篇
现状与发展   72篇
一般理论   34篇
预防医学   9560篇
眼科学   3503篇
药学   2156篇
  2篇
中国医学   13篇
肿瘤学   12973篇
  2024年   690篇
  2023年   4863篇
  2022年   1331篇
  2021年   3442篇
  2020年   6234篇
  2019年   2540篇
  2018年   7819篇
  2017年   7692篇
  2016年   8764篇
  2015年   8787篇
  2014年   16016篇
  2013年   16434篇
  2012年   6812篇
  2011年   6820篇
  2010年   11053篇
  2009年   14868篇
  2008年   7015篇
  2007年   5374篇
  2006年   7800篇
  2005年   4995篇
  2004年   4256篇
  2003年   3115篇
  2002年   3127篇
  2001年   3896篇
  2000年   3059篇
  1999年   3303篇
  1998年   3845篇
  1997年   3615篇
  1996年   3519篇
  1995年   3339篇
  1994年   2088篇
  1993年   1665篇
  1992年   1438篇
  1991年   1471篇
  1990年   1121篇
  1989年   1229篇
  1988年   1078篇
  1987年   902篇
  1986年   941篇
  1985年   760篇
  1984年   599篇
  1983年   553篇
  1982年   575篇
  1981年   469篇
  1980年   420篇
  1979年   338篇
  1978年   361篇
  1977年   424篇
  1975年   293篇
  1972年   310篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Anxiety disorders and anxiety symptoms are highly prevalent in the general population and more so in the medically ill. They have a number of negative consequences for these patients and may worsen the outcome of the medical illness and increase health care utilization. In the evaluation of these patients, it is of paramount importance to identify the etiology of the anxiety and, in particular, to differentiate primary from secondary anxiety. Management includes medications (especially benzodiazepines and selective serotonin reuptake inhibitors) and psychotherapy (particularly cognitive-behavioral therapy).  相似文献   
22.
23.
Wound healing involves a number of cellular and molecular events, many of which are controlled by soluble growth factors. In the process of healing, hepatocyte growth factor, a cytokine known to act as mitogen, motogen, and morphogen, has been postulated to play multiple roles during several stages of this complex biological process. Produced primarily by stromal fibroblasts, hepatocyte growth factor regulates angiogenesis, vascular permeability, cell migration, matrix deposition and degradation, and other biological processes. The current article discusses recent progress in understanding the multiple roles played by this growth factor in tissue repair.  相似文献   
24.
To produce a stable epidermis, keratinocytes need to be firmly attached to the basement membrane. However, following wounding, keratinocytes are required to develop a migratory phenotype in order to reepithelialize the wound. To investigate some of the issues underlying reepithelialization, we have developed a three-dimensional in vitro model of tissue-engineered skin, comprising sterilized human dermis seeded with human keratinocytes and dermal fibroblasts. Using this model, we have shown that the inclusion of fibroblasts within the model increases the stability of keratinocyte attachment. We have also demonstrated that keratinocyte migration occurs most effectively in the absence of a basement membrane and following the inclusion of fibroblasts in the model. In addition, subjecting the keratinocyte layer to mechanical trauma induces a migratory phenotype. We conclude that this three-dimensional in vitro wound model can be used to increase our understanding of the factors that enhance keratinocyte migration and hence wound healing in vivo.  相似文献   
25.
OBJECTIVES: Patients undergoing emergent endotracheal intubation are at increased risk for developing pneumonia. Although numerous strategies have been investigated to reduce ventilator-associated pneumonia (VAP), the incidence of VAP and its associated mortality remains high. This investigation tested the hypothesis that LiquiVent (Alliance Pharmaceutical, San Diego, CA-LV) delivered antibiotics (via spray-dried microspheres-SDM) would improve survival in a rat model of descending gram-negative pneumonia. METHODS: Wistar rats (n = 49) were randomized to receive prophylaxis with 1). nothing (controls); 2). intramuscular (IM) tobramycin, 3). intratracheal LV plus SDM shells (vehicle), 4). intratracheal LV plus SDM shells plus IM tobramycin, or 5). intratracheal LV plus SDM containing 1 mg/kg of tobramycin. All interventions were given 24 hours before a bacterial challenge with 10(8) colony-forming units of intratracheal Klebsiella pneumoniae. Mortality at ten days was the sole outcome measure. Survival in individual groups was compared with controls by Fisher's exact test with Bonferroni correction for multiple comparisons. RESULTS: All animals in the control group died of pneumonia within ten days of bacterial inoculation (0% survival). Prophylaxis with either IM tobramycin or SDM vehicle plus IM tobramycin provided no protection (0% survival). This is in sharp contrast to the cohort receiving pretreatment with tobramycin-containing SDM delivered via LV, in which 60% of the animals survived to study completion (p < 0.05). CONCLUSIONS: Prophylaxis with SDM containing antibiotics delivered in low-dose LV provided significant protection in a rat model of descending gram-negative pneumonia. These data support the hypothesis that perfluorocarbon-delivered intratracheal antimicrobials may be useful in the prevention of VAP.  相似文献   
26.
We present a case of intrapulmonary metastasis developing 18 years after complete resection of thymoma. An 8 mm nodule in the lower lobe of the left lung was noted on chest X-ray in a 76-year-old woman who had undergone complete resection of Masaoka’s stage II thymoma 18 years earlier. Since the nodule grew to 17 mm during a 2-year follow-up, wedge resection was performed. The lesion was histologically diagnosed as an intrapulmonary metastasis from thymoma. Extremely late recurrence after complete resection of thymoma is discussed.  相似文献   
27.
28.
29.
30.
OBJECTIVE: To assess whether pharmacokinetic drug interactions occur when sertraline is added to antipsychotic medications. METHOD: Forty-eight patients with remitted DSM-IV schizophrenia and comorbid major depression were randomized to placebo for 6 weeks or sertraline 50 mg for 4 weeks followed by sertraline 50 mg to 100 mg for 2 weeks for nonresponders. Treatment with the patients' usual antipsychotic continued. Weekly clinical outcome assessments occurred for 6 weeks, and serum samples for drug monitoring were collected at Weeks 1, 5, and 6. Serum concentrations of sertraline and antipsychotics were measured with standard assays. RESULTS: In both placebo- and sertraline-treated groups, most patients displayed minor fluctuations in antipsychotic serum levels over 6 weeks. There was no clinical evidence of drug interactions in the sertraline-treated group. CONCLUSIONS: Clinically significant adverse effects did not occur despite variable antipsychotic serum levels with or without sertraline. Concern about pharmacokinetic interactions should not deter the use of sertraline for depression in individuals with schizophrenia.  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