全文获取类型
收费全文 | 5401篇 |
免费 | 320篇 |
国内免费 | 113篇 |
专业分类
耳鼻咽喉 | 101篇 |
儿科学 | 138篇 |
妇产科学 | 57篇 |
基础医学 | 742篇 |
口腔科学 | 128篇 |
临床医学 | 475篇 |
内科学 | 1117篇 |
皮肤病学 | 192篇 |
神经病学 | 337篇 |
特种医学 | 634篇 |
外科学 | 742篇 |
综合类 | 55篇 |
预防医学 | 221篇 |
眼科学 | 65篇 |
药学 | 429篇 |
中国医学 | 50篇 |
肿瘤学 | 351篇 |
出版年
2023年 | 32篇 |
2022年 | 87篇 |
2021年 | 139篇 |
2020年 | 75篇 |
2019年 | 91篇 |
2018年 | 149篇 |
2017年 | 94篇 |
2016年 | 165篇 |
2015年 | 196篇 |
2014年 | 299篇 |
2013年 | 302篇 |
2012年 | 383篇 |
2011年 | 370篇 |
2010年 | 225篇 |
2009年 | 240篇 |
2008年 | 253篇 |
2007年 | 287篇 |
2006年 | 264篇 |
2005年 | 261篇 |
2004年 | 209篇 |
2003年 | 175篇 |
2002年 | 180篇 |
2001年 | 98篇 |
2000年 | 85篇 |
1999年 | 91篇 |
1998年 | 80篇 |
1997年 | 89篇 |
1996年 | 105篇 |
1995年 | 80篇 |
1994年 | 56篇 |
1993年 | 66篇 |
1992年 | 42篇 |
1991年 | 51篇 |
1990年 | 39篇 |
1989年 | 61篇 |
1988年 | 51篇 |
1987年 | 55篇 |
1986年 | 37篇 |
1985年 | 39篇 |
1984年 | 28篇 |
1983年 | 37篇 |
1982年 | 30篇 |
1981年 | 20篇 |
1980年 | 23篇 |
1979年 | 15篇 |
1978年 | 10篇 |
1977年 | 17篇 |
1976年 | 10篇 |
1975年 | 13篇 |
1974年 | 8篇 |
排序方式: 共有5834条查询结果,搜索用时 15 毫秒
91.
The aim of this study was to assess the expression of significant components of autophagy including beclin-1, light chain (LC) 3A, LC3B, and p62 in the molecular subtypes of triple-negative breast cancer (TNBC) and to evaluate the implications of the results. Tissues from 119 cases of TNBC were used for a tissue microarray. Expression of cytokeratin (CK) 5/6, epidermal growth factor receptor (EGFR), claudin 3, claudin 4, claudin7, E-cadherin, androgen receptor (AR), and gamma-glutamyltransferase 1 (GGT-1) was detected by immunohistochemical staining of the tissue microarrays. According to the results, the 119 cases of TNBC were subclassified into basal-like type (CK5/6-positive and/or EGFR-positive group), molecular apocrine type (AR-positive and/or GGT-1-positive group), claudin low type (claudin 3-, claudin 4-, or claudin 7-negative and/or E-cadherin-negative group), mixed type (having the features of more than two types), or null type (none of the above). Immunohistochemical staining for autophagy-related markers including beclin-1, LC3A, LC3B, and p62 was performed to evaluate the difference between clinicopathological parameters. TNBCs were categorized as basal-like type (36 patients, 30.3?%), molecular apocrine type (8 patients, 6.7?%), claudin low type (16 patients, 13.4?%), mixed type (37 patients, 31.1?%), and null type (22 patients, 18.5?%). Expression of nuclear p62 was higher in the molecular apocrine type and claudin low type than in other types of TNBC (p?=?0.008). Expression of beclin-1 was higher in molecular apocrine type than in other TNBC types (p?=?0.039). Expression of LC3A and LC3B showed no difference between the molecular subtypes. Multivariate Cox analysis revealed that the negative expression of p62 was associated with shorter disease-free survival [p?=?0.012; odds ratio, 3.192; 95?% confidence interval (CI), 1.293?C7.882] and shorter overall survival (p?=?0.009; odds ratio, 3.895; 95?% CI, 1.409?C10.771). Among the subtypes of TNBC, molecular apocrine breast cancer showed a higher expression of nuclear p62 and beclin-1 than others, which reflected higher autophagy activity. 相似文献
92.
Byung-Ho Yoon Lynne C. Jones Chung-Hwan Chen Edward Y. Cheng Quanjun Cui Wolf Drescher Wakaba Fukushima Valerie Gangji Stuart B. Goodman Yong-Chan Ha Philippe Hernigou Marc Hungerford Richard Iorio Woo-Lam Jo Vikas Khanduja Harry Kim Shin-Yoon Kim Tae-Young Kim Kyung-Hoi Koo 《The Journal of arthroplasty》2019,34(1):169-174.e1
Background
Although alcohol is a leading risk factor for osteonecrosis of the femoral head (ONFH) and its prevalence reportedly ranges from 20% to 45%, there are no unified classification criteria for this subpopulation. In 2015, Association Research Circulation Osseous decided to develop classification criteria for alcohol-associated ONFH.Methods
In June of 2017, Association Research Circulation Osseous formed a task force to conduct a Delphi survey. The task force invited 28 experts in osteonecrosis/bone circulation from 8 countries. Each round of the Delphi survey included questionnaires, analysis of replies, and feedback reports to the panel. After 3 rounds of the survey, consensus was reached on the classification criteria. The response rates for the 3 Delphi rounds were 100% (round 1), 96% (round 2), and 100% (round 3).Results
The consensus on the classification criteria of alcohol-associated ONFH included the following: (1) patients should have a history of alcohol intake >400 mL/wk (320 g/wk, any type of alcoholic beverage) of pure ethanol for more than 6 months; (2) ONFH should be diagnosed within 1 year after alcohol intake of this dose; and (3) patients should not have other risk factor(s).Conclusion
ARCO-established classification criteria to standardize clinical studies concerning AA-ONFH. 相似文献93.
94.
Ok-Seon Kwon Ensel Oh Jeong-Rak Park Ji-Seon Lee Gab-Yong Bae Jae-Hyung Koo Hyongbum Kim Yoon-La Choi Young Soo Choi Jhingook Kim Hyuk-Jin Cha 《Oncotarget》2015,6(39):41916-41928
While metastasis, the main cause of lung cancer-related death, has been extensively studied, the underlying molecular mechanism remains unclear. A previous clinicogenomic study revealed that expression of N-acetylgalactosaminyltransferase (GalNAc-T14), is highly inversely correlated with recurrence-free survival in those with non-small cell lung cancer (NSCLC). However, the underlying molecular mechanism(s) has not been determined. Here, we showed that GalNAc-T14 expression was positively associated with the invasive phenotype. Microarray and biochemical analyses revealed that HOXB9, the expression of which was increased in a GalNAc-T14-dependent manner, played an important role in metastasis. GalNAc-T14 increased the sensitivity of the WNT response and increased the stability of the β-catenin protein, leading to induced expression of HOXB9 and acquisition of an invasive phenotype. Pharmacological inhibition of β-catenin in GalNAc-T14-expressing cancer cells suppressed HOXB9 expression and invasion. A meta-analysis of clinical genomics data revealed that expression of GalNAc-T14 or HOXB9 was strongly correlated with reduced recurrence-free survival and increased hazard risk, suggesting that targeting β-catenin within the GalNAc-T14/WNT/HOXB9 axis may be a novel therapeutic approach to inhibit metastasis in NSCLC. 相似文献
95.
96.
97.
98.
Expression of fibrinogen receptors during activation and subsequent desensitization of human platelets by epinephrine 总被引:2,自引:0,他引:2
Epinephrine causes platelet aggregation and secretion by interacting with alpha 2-adrenergic receptors on the platelet surface. Platelet aggregation requires the binding of fibrinogen to a specific receptor on the membrane glycoprotein IIb-IIIa complex. Although the IIb-IIIa complex is identifiable on the surface of resting platelets, the fibrinogen receptor is expressed only after platelet activation. The current studies were designed to examine the effect of occupancy of platelet alpha 2-adrenergic receptors by epinephrine on the expression of fibrinogen receptors and on the aggregation of platelets. The ability of epinephrine to induce the expression of fibrinogen receptors was studied under two different conditions: acute stimulation (less than 1 min) and prolonged stimulation (50 to 90 min), the latter of which is associated with a reduction or "desensitization" of the platelet aggregation response. Expression of the fibrinogen receptor was monitored with 125I-fibrinogen as well as with 125I-PAC-1 (PAC-1), a monoclonal antibody that binds to the glycoprotein IIb-IIIa complex only after platelets are activated. Epinephrine caused an immediate increase in PAC-1 and fibrinogen binding that was dependent on occupancy of the alpha 2-receptor by epinephrine and on the presence of extracellular free Ca (KCa = 30 mumol/L). By itself, 1 mmol/L Mg was unable to support induction of the fibrinogen receptor by epinephrine. However, it did decrease the Ca requirement by about two orders of magnitude. Prolonged stimulation of unstirred platelets by epinephrine led to a 70% decrease in the aggregation response when the platelets were subsequently stirred. Despite their decreased aggregation response, desensitized platelets bound PAC-1 and fibrinogen normally, indicating that the loss of aggregation was not due simply to a decrease in fibrinogen receptor expression. Although desensitization was not affected by pretreatment of the platelets with aspirin, it was partially prevented when extracellular Ca was chelated by EDTA during the long incubation with epinephrine. These studies demonstrate that once platelet alpha 2-adrenergic receptors are occupied by epinephrine, extracellular Ca is involved in initiating the aggregation response by supporting the induction of the fibrinogen receptor and the binding of fibrinogen. Furthermore. Ca-dependent reactions subsequent to fibrinogen binding may be necessary for maximal platelet aggregation and are impaired when platelets become desensitized to epinephrine. 相似文献
99.
100.