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   800篇
  免费   39篇
  国内免费   2篇
耳鼻咽喉   13篇
儿科学   39篇
妇产科学   12篇
基础医学   72篇
口腔科学   10篇
临床医学   67篇
内科学   141篇
皮肤病学   17篇
神经病学   95篇
特种医学   17篇
外科学   150篇
综合类   16篇
预防医学   52篇
眼科学   28篇
药学   61篇
中国医学   7篇
肿瘤学   44篇
  2024年   1篇
  2023年   5篇
  2022年   13篇
  2021年   34篇
  2020年   21篇
  2019年   14篇
  2018年   21篇
  2017年   12篇
  2016年   18篇
  2015年   24篇
  2014年   38篇
  2013年   57篇
  2012年   61篇
  2011年   78篇
  2010年   30篇
  2009年   30篇
  2008年   59篇
  2007年   60篇
  2006年   52篇
  2005年   50篇
  2004年   37篇
  2003年   25篇
  2002年   25篇
  2001年   11篇
  2000年   16篇
  1999年   6篇
  1998年   3篇
  1997年   3篇
  1996年   4篇
  1995年   4篇
  1994年   2篇
  1992年   6篇
  1991年   5篇
  1990年   3篇
  1989年   2篇
  1988年   2篇
  1987年   4篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1976年   1篇
排序方式: 共有841条查询结果,搜索用时 156 毫秒
51.
Numerous models have been developed to address key elements in the biology of breast cancer development and progression. No model is ideal, but the most useful are those that reflect the natural history and histopathology of human disease, and allow for basic investigations into underlying cellular and molecular mechanisms. We describe two types of models: those that are directed toward early events in breast cancer development (hyperplastic alveolar nodules [HAN] murine model, MCF10AT human xenograft model); and those that seek to reflect the spectrum of metastatic disease (murine sister cell lines 67, 168, 4T07, 4T1). Collectively, these models provide cell lines that represent all of the sequential stages of progression in breast disease, which can be modified to test the effect of genetic changes.  相似文献   
52.
The PCR-ELISA represents a promising advance for diagnosis of visceral leishmaniasis (VL) in blood samples. However, the method has been validated mostly with HIV-positive patients who are known to have high levels of parasitaemia. We developed a new PCR-ELISA assay for specific detection of Leishmania in patients' blood and validated it in Nepalese subjects with clinically suspected VL, almost all of whom were HIV-negative. For blood samples, PCR-ELISA was more sensitive (83.9%) than conventional PCR (73.2%), and demonstrated 100% and 87.2% specificity when using healthy controls who had never travelled to a VL-endemic area and controls from a VL-endemic area as references, respectively. We have demonstrated the ability of PCR-ELISA to detect parasites in blood of HIV-negative patients. The method could be used for epidemiological as well as clinical purposes, as it reduces the need for traumatic bone marrow sampling and risky spleen aspiration.  相似文献   
53.
54.
55.
Background Non malignant tracheo-esophageal fistula is a rare entity, which is usually post traumatic, post inflammatory or could be a delayed presentation of congenital tracheo-esophageal fistula. Patients and Methods In this retrospective study of seven cases, we aim to document and evaluate the causes, presentation and treatment modalities. Results All the cases underwent surgical intervention, with single stage definitive repair in four cases and two stage repair in three cases. There was no mortality, and minimal morbidity. Conclusions Being a benign disease with fatal complications, early diagnosis and early surgical intervention is the key to successful management of non-malignant tracheo-esophageal fistula.  相似文献   
56.
Serotonergic systems play important roles in modulating behavioral arousal, including behavioral arousal and vigilance associated with anxiety states. To further our understanding of the neural systems associated with increases in anxiety states, we investigated the effects of multiple anxiogenic drugs on topographically organized subpopulations of serotonergic neurons using double immunohistochemical staining for c-Fos and tryptophan hydroxylase combined with topographical analysis of the rat dorsal raphe nucleus (DR). Anxiogenic drugs with diverse pharmacological properties including the adenosine receptor antagonist caffeine, the serotonin 5-HT2A/2C receptor agonist m-chlorophenyl piperazine (mCPP), the alpha2-adrenoreceptor antagonist yohimbine, and the benzodiazepine receptor partial inverse agonist N-methyl-beta-carboline-3-carboxamide (FG-7142) induced increases in behavioral arousal and vigilance behaviors consistent with an increase in anxiety state. In addition, these anxiogenic drugs, excluding yohimbine, had convergent actions on an anatomically-defined subset of serotonergic neurons within the middle and caudal, dorsal subdivision of the DR. High resolution topographical analysis revealed that at the mid-rostrocaudal level, caffeine and FG-7142 had convergent effects on c-Fos expression in serotonergic neurons that were restricted to a previously undefined region, which we have named the shell region of the dorsal part of the dorsal raphe nucleus (DRDSh), that overlaps the anatomical border between the dorsal part of the dorsal raphe nucleus, the ventral part of the dorsal raphe nucleus (DRV), and the ventrolateral part of the dorsal raphe nucleus (DRVL). Retrograde tracing methods revealed that DRDSh contains large numbers of neurons projecting to the basolateral amygdaloid nucleus, a forebrain structure important for emotional appraisal and modulation of anxiety-related physiological and behavioral responses. Together these findings support the hypothesis that there is a functional topographical organization in the DR and are consistent with the hypothesis that anxiogenic drugs have selective actions on a subpopulation of serotonergic neurons projecting to a distributed central autonomic and emotional motor control system regulating anxiety states and anxiety-related physiological and behavioral responses.  相似文献   
57.
58.
59.
60.
Patients with bipolar disorder show cognitive deficits and disorganized behavior, which may reflect a disturbance in neural synchronization. We tested whether EEG measures of auditory neural synchronization were abnormal in bipolar disorder. Nineteen symptomatic patients with bipolar disorder and 32 non-psychiatric control subjects were evaluated. Click trains (500 ms duration) presented at 20, 30, 40 and 50 Hz were used to evoke EEG synchronization. Patients with bipolar disorder showed reduced power across the frequencies of stimulation. Phase-locking across trials was also disturbed in bipolar disorder, consistent with poor phase synchronization between the stimulus and EEG. Abnormal high frequency neural synchronization may contribute to cognitive deficits in bipolar disorder.  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