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   6260篇
  免费   314篇
  国内免费   31篇
耳鼻咽喉   64篇
儿科学   123篇
妇产科学   88篇
基础医学   637篇
口腔科学   103篇
临床医学   376篇
内科学   1925篇
皮肤病学   59篇
神经病学   655篇
特种医学   170篇
外科学   762篇
综合类   40篇
一般理论   5篇
预防医学   417篇
眼科学   238篇
药学   417篇
  1篇
中国医学   18篇
肿瘤学   507篇
  2023年   49篇
  2022年   104篇
  2021年   215篇
  2020年   104篇
  2019年   184篇
  2018年   201篇
  2017年   159篇
  2016年   157篇
  2015年   168篇
  2014年   213篇
  2013年   337篇
  2012年   485篇
  2011年   467篇
  2010年   278篇
  2009年   246篇
  2008年   424篇
  2007年   437篇
  2006年   430篇
  2005年   373篇
  2004年   278篇
  2003年   301篇
  2002年   265篇
  2001年   79篇
  2000年   56篇
  1999年   47篇
  1998年   61篇
  1997年   42篇
  1996年   36篇
  1995年   28篇
  1994年   24篇
  1993年   15篇
  1992年   39篇
  1991年   30篇
  1990年   22篇
  1989年   30篇
  1988年   27篇
  1987年   23篇
  1986年   17篇
  1985年   14篇
  1984年   12篇
  1983年   9篇
  1982年   18篇
  1981年   13篇
  1980年   9篇
  1979年   7篇
  1978年   8篇
  1977年   7篇
  1976年   8篇
  1975年   6篇
  1974年   7篇
排序方式: 共有6605条查询结果,搜索用时 15 毫秒
91.
Glioblastoma (GBM) is one of the most highly aggressive neoplasms of the central nervous system. Extra-cranial metastases in GBM are rare. Here we present the case of a 26-year-old man with extra-cranial metastasis of a frontal lobe GBM to the parotid gland, cervical lymph nodes, and bones, with initial diagnosis made by fine needle aspiration cytology (FNAC) of the parotid gland. FNAC is a reliable technique in the study of primary and secondary parotid gland neoplasms, allowing a presumptive diagnosis in difficult cases. We correlate the cytologic, histopathologic, and immunohistochemical findings in this case and discuss previous literature reports.  相似文献   
92.
Two hallmarks of Alzheimer diseases are the continuous inflammatory process, and the brain deposit of Amyloid b (Aβ), a cytotoxic protein. The intracellular accumulation of Aβ25–35 fractions, in the absence of Heat Shock proteins (Hs?s), could be responsible for its cytotoxic activity. As, pro-inflammatory mediators and nitric oxide control the expression of Hs?s, our aim was to investigate the effect of Aβ25–35 on the concentration of IL-1β, TNF-α and nitrite levels, and their relation to pHSF-1, Hsp-60, -70 and -90 expressions, in the rat C6 astrocyte cells. Interleukin-specific ELISA kits, immunohistochemistry with monoclonal anti-Hsp and anti pHSF-1 antibodies, and histochemistry techniques, were used. Our results showed that Aβ25–35 treatment of C6 cells increased, significantly and consistently the concentration of IL-1β, TNF-α and nitrite 3 days after initiating treatment. The immunoreactivity of C6 cells to Hsp-70 reached its peak after 3 days of treatment followed by an abrupt decrease, as opposed to Hsp-60 and -90 expressions that showed an initial and progressive increase after 3 days of Aβ25–35 treatment. pHSF-1 was identified throughout the experimental period. Nevertheless, progressive and sustained cell death was observed during all the treatment times and it was not caspase-3 dependent. Our results suggest that Hsp-70 temporary expression serves as a trigger to inhibit casapase-3 pathway and allow the expression of Hsp-60 and -90 in C6 astrocytoma cells stimulated with Aβ25–35.  相似文献   
93.
94.
Aim: Circulating immune cell activation is associated with worse outcome in adult and animal models of brain injury. Our aim was to profile the systemic inflammatory response over the first week of life in infants at risk of neonatal encephalopathy (NE) and correlate early neutrophil and monocyte endotoxin and activation responses with outcome.

Methods: Prospective observational study in a tertiary referral university hospital including 22 infants requiring resuscitation at birth who had serial (five time points) neutrophil and monocyte CD11b (marker of cell adhesion), intracellular reactive oxygen intermediates (ROI; cell activation) and Toll-like receptor (TLR; endotoxin recognition) before and after endotoxin stimulation ex vivo compared to neonatal controls.

Results: All neonates requiring resuscitation at delivery (n?=?122 samples) had higher neutrophil and monocyte CD11b and TLR-4 expression compared with adults and neonatal controls. Neonates with abnormal neuroimaging and/or severe NE had increased CD11b, ROI and TLR-4. Increased polymorphonuclear leukocytes TLR-4 expression was associated with increased mortality in infants with NE.

Conclusion: Innate immune dysregulation in the first week of life is associated with severity of outcome in neonatal brain injury in this cohort and may be amenable to immunomodulation.  相似文献   
95.

Background

Adipose tissue (AT) dysfunction in obesity is commonly linked to insulin resistance and promotes the development of metabolic disease. Bariatric surgery (BS) represents an effective strategy to reduce weight and to improve metabolic health in morbidly obese subjects. However, the mechanisms and pathways that are modified in AT in response to BS are not fully understood, and few information is still available as to whether these may vary depending on the metabolic status of obese subjects.

Methods

Abdominal subcutaneous adipose tissue (SAT) samples were obtained from morbidly obese women (n?=?18) before and 13.3?±?0.37 months after BS. Obese women were stratified into two groups: normoglycemic (NG; Glu?<?100 mg/dl, HbA1c <5.7 %) or insulin resistant (IR; Glu 100–126 mg/dl, HbA1c 5.7–6.4 %) (n?=?9/group). A multi-comparative proteomic analysis was employed to identify differentially regulated SAT proteins by BS and/or the degree of insulin sensitivity. Serum levels of metabolic, inflammatory, and anti-oxidant markers were also analyzed.

Results

Before surgery, NG and IR subjects exhibited differences in AT proteins related to inflammation, metabolic processes, the cytoskeleton, and mitochondria. BS caused comparable weight reductions and improved glucose homeostasis in both groups. However, BS caused dissimilar changes in metabolic enzymes, inflammatory markers, cytoskeletal components, mitochondrial proteins, and angiogenesis regulators in NG and IR women.

Conclusions

BS evokes significant molecular rearrangements indicative of improved AT function in morbidly obese women at either low or high metabolic risk, though selective adaptive changes in key cellular processes occur depending on the initial individual’s metabolic status.
  相似文献   
96.
97.
98.
99.
A suitable dynamic 3D model that allows the simulation of the inguinal region with real-time performance on a personal computer was developed. A geometric model adjusted to real data was created by means of semiautomatic contour segmentation of anatomic units from the visible human project and data generated from classical anatomic information. A dynamic model included converting muscular units from their continuous geometric representation into a set of voxels and then real-time interaction and performance. The current implementation enables deformation of the realistic model associated with pushing and stretching interaction, allowing immersion in the anatomy of the inguinal structures. The model does not allow simulation of surgical interventions.  相似文献   
100.

Background

Unintentional underfeeding is common in patients receiving enteral nutrition (EN), and is associated with increased risk of malnutrition complications. Protocols for EN in critically ill patients have been shown to enhance adequacy, resulting in better clinical outcomes; however, outside of intensive care unit (ICU) settings, the influence of a protocol for EN is unknown.

Objective

To evaluate the efficacy and safety of implementing an EN protocol in a noncritical setting.

Design

Randomized controlled clinical trial.

Participants and settings

This trial was conducted from 2014 to 2016 in 90 adult hospitalized patients (non-ICU) receiving exclusively EN. Patients with carcinomatosis, ICU admission, or <72 hours of EN were excluded.

Intervention

The intervention group received EN according to a protocol, whereas the control group was fed according to standard practice.

Main outcome measures

The proportion of patients receiving ≥80% of their caloric target at Day 4 after EN initiation.

Statistical analyses performed

Student t test or Wilcoxon rank-sum test were used for continuous variables and the difference between the groups in the time to receipt of the optimal amount of nutrition was analyzed using Kaplan-Meier curves.

Results

Forty-five patients were randomized to each group. At Day 4 after EN initiation, 61% of patients in the intervention arm had achieved the primary end point compared with 23% in the control group (P=0.001). In malnourished patients, 63% achieved the primary end point in the intervention group compared with 16% in the control group (P=0.003). The cumulative deficit on Day 4 was lower in the intervention arm compared with the control arm: 2,507 kcal (interquartile range [IQR]=1,262 to 2,908 kcal) vs 3,844 kcal (IQR=2,620 to 4,808 kcal) (P<0.001) and 116 g (IQR=69 to 151 g) vs 191 g (IQR=147 to 244 g) protein (P<0.001), respectively. The rates of gastrointestinal complications were not significantly different between groups.

Conclusions

Implementation of an EN protocol outside the ICU significantly improved the delivery of calories and protein when compared with current standard practice without increasing gastrointestinal complications.  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