全文获取类型
收费全文 | 580篇 |
免费 | 69篇 |
国内免费 | 26篇 |
出版年
2024年 | 1篇 |
2023年 | 13篇 |
2022年 | 17篇 |
2021年 | 20篇 |
2020年 | 23篇 |
2019年 | 23篇 |
2018年 | 25篇 |
2017年 | 27篇 |
2016年 | 13篇 |
2015年 | 17篇 |
2014年 | 40篇 |
2013年 | 29篇 |
2012年 | 21篇 |
2011年 | 28篇 |
2010年 | 33篇 |
2009年 | 33篇 |
2008年 | 18篇 |
2007年 | 27篇 |
2006年 | 27篇 |
2005年 | 14篇 |
2004年 | 18篇 |
2003年 | 28篇 |
2002年 | 17篇 |
2001年 | 22篇 |
2000年 | 13篇 |
1999年 | 11篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 9篇 |
1994年 | 7篇 |
1993年 | 9篇 |
1992年 | 21篇 |
1991年 | 12篇 |
1990年 | 20篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有675条查询结果,搜索用时 508 毫秒
131.
132.
《Tissue & cell》2016,48(5):461-474
Cytological evaluation by microscopic image-based characterization [imprint cytology (IC) and fine needle aspiration cytology (FNAC)] plays an integral role in primary screening/detection of breast cancer. The sensitivity of IC and FNAC as a screening tool is dependent on the image quality and the pathologist’s level of expertise. Computer-aided diagnosis (CAD) is used to assists the pathologists by developing various machine learning and image processing algorithms. This study reviews the various manual and computer-aided techniques used so far in breast cytology. Diagnostic applications were studied to estimate the role of CAD in breast cancer diagnosis. This paper presents an overview of image processing and pattern recognition techniques that have been used to address several issues in breast cytology-based CAD including slide preparation, staining, microscopic imaging, pre-processing, segmentation, feature extraction and diagnostic classification. This review provides better insights to readers regarding the state of the art the knowledge on CAD-based breast cancer diagnosis to date. 相似文献
133.
134.
135.
Structural determinants of increased susceptibility to dehydration‐induced cavitation in post‐fire resprouting chaparral shrubs
下载免费PDF全文
![点击此处可从《Plant, cell & environment》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Anna L. Jacobsen Michael F. Tobin Hayden S. Toschi Marta I. Percolla R. Brandon Pratt 《Plant, cell & environment》2016,39(11):2473-2485
It is well established that transpiration and photosynthetic rates generally increase in resprouting shoots after fire in chaparral shrublands. By contrast, little is known about how plant hydraulic function varies during this same recovery period. We hypothesized that vascular traits, both functional and structural, would also shift in order to support this heightened level of gas exchange and growth. We examined stem xylem‐specific hydraulic conductivity (Ks) and resistance to cavitation (P50) for eight chaparral shrub species as well as several potential xylem structural determinants of hydraulic function and compared established unburned plants and co‐occurring post‐fire resprouting plants. Unburned plants were generally more resistant to cavitation than resprouting plants, but the two groups did not differ in Ks. Resprouting plants had altered vessel structure compared with unburned plants, with resprouting plants having both wider diameter vessels and higher inter‐vessel pit density. For biomechanics, unburned plants had both stronger and denser stem xylem tissue than resprouting plants. Shifts in hydraulic structure and function resulted in resprouting plants being more vulnerable to dehydration. The interaction between time since disturbance (i.e. resprouting versus established stands) and drought may complicate attempts to predict mortality risk of resprouting plants. 相似文献
136.
Bone‐marrow‐derived mesenchymal stem cells inhibit gastric aspiration lung injury and inflammation in rats
下载免费PDF全文
![点击此处可从《Journal of cellular and molecular medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jing Zhou Liyan Jiang Xuan Long Cuiping Fu Xiangdong Wang Xiaodan Wu Zilong Liu Fen Zhu Jindong Shi Shanqun Li 《Journal of cellular and molecular medicine》2016,20(9):1706-1717
Gastric aspiration lung injury is one of the most common clinical events. This study investigated the effects of bone‐marrow‐derived mesenchymal stem cells (BMSCs) on combined acid plus small non‐acidified particle (CASP)‐induced aspiration lung injury. Enhanced green fluorescent protein (EGFP+) or EGFP? BMSCs or 15d‐PGJ2 were injected via the tail vein into rats immediately after CASP‐induced aspiration lung injury. Pathological changes in lung tissues, blood gas analysis, the wet/dry weight ratio (W/D) of the lung, levels of total proteins and number of total cells and neutrophils in bronchoalveolar lavage fluid (BALF) were determined. The cytokine levels were measured using ELISA. Protein expression was determined by Western blot. Bone‐marrow‐derived mesenchymal stem cells treatment significantly reduced alveolar oedema, exudation and lung inflammation; increased the arterial partial pressure of oxygen; and decreased the W/D of the lung, the levels of total proteins and the number of total cells and neutrophils in BALF in the rats with CASP‐induced lung injury. Bone‐marrow‐derived mesenchymal stem cells treatment decreased the levels of tumour necrosis factor‐α and Cytokine‐induced neutrophil chemoattractant (CINC)‐1 and the expression of p‐p65 and increased the levels of interleukin‐10 and 15d‐PGJ2 and the expression of peroxisome proliferator‐activated receptor (PPAR)‐γ in the lung tissue in CASP‐induced rats. Tumour necrosis factor‐α stimulated BMSCs to secrete 15d‐PGJ2. A tracking experiment showed that EGFP+ BMSCs were able to migrate to local lung tissues. Treatment with 15d‐PGJ2 also significantly inhibited CASP‐induced lung inflammation and the production of pro‐inflammatory cytokines. Our results show that BMSCs can protect lung tissues from gastric aspiration injury and inhibit lung inflammation in rats. A beneficial effect might be achieved through BMSC‐derived 15d‐PGJ2 activation of the PPAR‐γ receptor, reducing the production of proinflammatory cytokines. 相似文献
137.
目的:研究超声内镜引导下细针穿刺活检(EUS-FNA)联合K-ras基因检测对胰腺癌的诊断价值,为临床诊疗提供依据。方法:选取2013年11月到2015年11月我院收治的胰腺占位病变患者90例,患者入院次日行EUS-FNA,检测患者血清及活检物中K-ras基因阳性率,比较EUS-FNA单独与EUS-FNA联合K-ras基因检测对胰腺癌诊断的准确率与敏感性。结果:90例胰腺占位病变者中,经病理证实胰腺癌56例,EUS-FNA单独与EUS-FNA联合K-ras基因分别检出胰腺癌50例、53例,准确率分别为89.29%、94.64%,敏感性分别为92.59%、98.15%,两组比较差异均有统计学意义(P0.05)。胰腺癌患者活检物中K-ras阳性率为83.93%,明显高于血清中的41.07%(P0.05)。结论:EUS-FNA联合K-ras基因检测可提高对胰腺癌诊断的准确率与敏感性。 相似文献
138.
At Northampton General Hospital a pathologist takes, stains and immediately reports aspirates at a fine needle aspiration clinic which is run in conjunction with a busy surgical breast clinic. the effect of various factors on the sensitivity of the technique have been quantified. Small tumour size, certain types of tumour and lesions difficult to palpate are causes of reduced sensitivity. Acellular samples had little effect on sensitivity. In this clinic trainee aspirators achieved good results early in their experience. After one year each had improved to the level of an experienced aspirator. 相似文献
139.
C. ÖRNDAL B. CARLÉN† M. ÅKERMAN† H. WILLÉN† N. MANDAHL S. HEIM§ A. RYDHOLM‡ F. MITELMAN 《Cytopathology》1991,2(5):261-270
A multidisciplinary approach was taken to characterize a soft tissue tumour. In smears prepared from aspirated material, uniform tumour cells, embedded in a myxoid matrix and partly arranged in a lace-like pattern, were found. Histopathology showed a lace-like pattern of cells in a matrix of hyaluronidase-stable mucins. Cytoplasmic positivity for S-100 protein was found in some tumour cells. Electron microscopic analysis revealed intracisternal aggregates of microtubules. All these features are consistent with the diagnosis of extraskeletal myxoid chondrosarcoma (EMC). DNA flow cytometry showed a diploid DNA content. Cytogenetic examination revealed the tumour karyotype 45, XY, t(2;11)(q31;p15), t(9;22)(q22.3;q12), dic(13;22)(p11;p13). Because similar 9;22-translocations have been described in two other cases of EMC, we conclude that t(9;22)(q22–31;q11–12) is a specific rearrangement in this tumour type. Cytogenetic analysis may thus be of diagnostic value in the examination of tumours with this and similar histologies. 相似文献
140.