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   279篇
  免费   11篇
  国内免费   3篇
耳鼻咽喉   2篇
儿科学   9篇
妇产科学   18篇
基础医学   32篇
口腔科学   21篇
临床医学   18篇
内科学   61篇
皮肤病学   6篇
神经病学   15篇
特种医学   10篇
外科学   69篇
综合类   2篇
预防医学   3篇
眼科学   3篇
药学   18篇
肿瘤学   6篇
  2024年   1篇
  2023年   4篇
  2022年   4篇
  2021年   6篇
  2020年   10篇
  2019年   11篇
  2018年   8篇
  2017年   9篇
  2016年   8篇
  2015年   8篇
  2014年   4篇
  2013年   21篇
  2012年   28篇
  2011年   17篇
  2010年   15篇
  2009年   20篇
  2008年   36篇
  2007年   22篇
  2006年   23篇
  2005年   12篇
  2004年   11篇
  2003年   5篇
  2002年   4篇
  2000年   2篇
  1997年   1篇
  1996年   1篇
  1989年   1篇
  1987年   1篇
排序方式: 共有293条查询结果,搜索用时 15 毫秒
1.
Type II collagen (CII) is of immunological interest because of its repetitive structure and properties as an autoantigen. The mouse gene has recently been cloned, thus enabling T cell-defined epitopes to be identified. Multiple novel epitopes on mouse CII are here detected in the autoreactive T cell response. The major response is directed to an epitope with residues 707-721 located on the CB10 fragment. Some 25 other epitopes are also recognized, including the autologous homologue of the 256-270 epitope which dominates in the response to foreign collagen. The cells reactive with mouse collagen peptides were of Th1 type, as judged by release of IFN-gamma. No significant reactivity was detected to mouse CII peptides during ongoing disease. Alignment of the mouse epitopes revealed a sequence motif with characteristic side chains at residues P1, P4 and P7, and to a lesser extent at P5, within a nonamer core sequence. Binding of these epitopes was simulated in a computer model of the I-Aq molecule, where peptides with anchor residues at P1, P4 and P7 were indeed found to fit the binding groove best. The spacing of pockets and the fine structure of the binding surface of the I-Aq molecule meshes with the repetitive structure of the collagen (X-Y-Gly), thus providing a likely explanation for the occurrence of multiple epitopes. Comparison with human DR binding motifs showed that the I-Aq motif resembles most closely that of the DR4 subtypes which predispose for rheumatoid arthritis.   相似文献   
2.
BACKGROUND: Nitric oxide (NO) has contradictory roles in the pathophysiology of allergic inflammation in both allergic rhinitis (AR) and asthma. Small amounts of NO produced by constitutive NO synthase (NOS) is anti-inflammatory, whereas large amounts produced by inducible NOS (iNOS) are proinflammatory. OBJECTIVE: To investigate the difference in constitutive endothelial NOS (eNOS) and iNOS expression in nonallergic and allergic mucosa and the possible relation of this to the coexistence of asthma in seasonal AR. METHODS: Seventeen patients (10 women and 7 men) with seasonal AR and 9 nonallergic patients (5 women and 4 men) with nasal septum deviation were enrolled. Inferior turbinate nasal biopsy specimens were obtained in all. Levels of eNOS and iNOS expressed as immunohistochemical scores (HSCOREs) were determined immunohistochemically from the specimens. RESULTS: The mean +/- SD HSCOREs for eNOS in patients with seasonal AR were not significantly different from those of the nonallergic controls (1.85 +/- 0.78 vs 1.63 +/- 0.54; P = .12). On the other hand, the mean +/- SD HSCOREs for iNOS were significantly higher in patients with seasonal AR (1.75 +/- 0.75 vs 0.71 +/- 0.6; P = .004). Furthermore, although eNOS expression was not different between seasonal AR patients with and without asthma, the mean +/- SD HSCOREs for iNOS were significantly higher in the patients with asthma (1.93 +/- 0.78 vs 1.65 +/- 0.55; P = .01). CONCLUSION: Increased expression of iNOS might have a role in the development of allergic inflammation in upper and lower airways and in comorbidity of AR and asthma.  相似文献   
3.
The effect of orthodontic‐surgical treatment on submental‐cervical region was evaluated in a very limited number of studies. The aim of this study was to evaluate submental‐cervical soft tissue contour changes following mandibular advancement and set‐back procedures via bilateral sagittal split ramus osteotomy. Sixty‐seven patients were included in this study. Group 1 consisted of 27 skeletal Class II patients who underwent mandibular advancement surgery, whereas Group 2 consisted of 40 skeletal Class III patients who underwent mandibular set‐back surgery. Various linear and angular measurements were performed on pre‐operative and sixth month post‐operative cephalometric radiographs. A new method was used to evaluate the amount of sagging at submental region. The submental length did not change in Group 1; however, it decreased significantly in Group 2 (P < 0·05). The angle between submental plane and facial plane decreased to 95·9° from 98·8° in Group 1(P < 0·05), whereas it increased to 93·1° from 88·2° in Group2 (P < 0·05). The change of submental soft tissue sag was almost stable in Group 1, while 0·34 mm increase of sag was observed in Group 2. This increase was not statistically significant (P > 0·05). Mandibular set‐back and advancement procedures do not remarkably change the submental sag following approximately 6 mm jaw movement. Although mandibular advancement did not significantly effect submental length, soft tissue followed mandibular set‐back with a ratio of 1:1 at C‐point to projection of soft tissue pogonion and 1:0·7 at C‐point to soft tissue menton distances.  相似文献   
4.
5.
6.
7.
Two series of amino‐1,4‐benzoquinones ( AQ1–18 ) based on the structural analogs of plastoquinones were synthesized and the structure–activity relationship against chronic myelogenous leukemia activity was examined. All of the synthesized compounds were tested for their cytotoxic effects on different leukemic cell lines. Of interest, AQ15 exhibited a better selectivity than the reference drug imatinib on cancer cells. Owing to this, AQ15 was selected for a further apoptosis/necrosis evaluation where AQ15 ‐treated K562 cells demonstrated similar apoptotic effects like imatinib‐treated cells at their IC50 values. The inhibitory effects of AQ15 and the other three compounds with various activities against eight tyrosine kinases, including ABL1, were investigated. AQ15 showed weak activity against ABL1, and a correlation was observed between the anti‐K562 and anti‐ABL1 activities. The binding mode of AQ15 into the ATP binding pocket of ABL1 kinase was predicted in silico, showing the formation of some key interactions. In addition, AQ15 was shown to suppress the downstream signaling of BCR‐ABL in K562 cells. Finally, AQ15 obviously cleaved DNA in the presence of an iron(II) complex system, indicating that this can be the major mechanism of its antiproliferative action, whereas the mild inhibition of ABL kinase is just in‐part mechanism of its overall outstanding cellular activity.  相似文献   
8.
9.
A total of 684 patients who had not been diagnosed with renal cyst but had undergone abdominal ultrasonography for various reasons were evaluated. Patients with and without renal cyst were classified into two groups and were compared in terms of hypertension (HT), hyperlipidemia (HL), diabetes mellitus (DM) and obesity (body mass index: ≥30 kg/m2) prevalence. Although 94 patients (13.7%) were established with a renal cyst, 590 patients (86.3%) did not have a renal cyst. The mean age of the patients established with a simple renal cyst was 67.3 ± 12.1 years (range: 28–82 years); 54 (57.4%) of them were women and 40 (42.6%) were men. Of the patients established with a simple renal cyst, 64 (68.1%) had HT, 40 (42.6%) had DM, 20 (21.3%) had HL, 42 (44.7%) were obese, 18 (19.1%) had nephrolithiasis, and 6 (6.4%) had urinary tract infection. Of the patients without a cyst, 272 (46.1%) had DM, 212 (35.9%) had HT, 122 (20.7%) had HL, and 96 (16.3%) were obese. HT and obesity were significantly higher in patients with a renal cyst when compared with those without a cyst. However, although HL incidence was higher in patients with a cyst, the difference was not significant statistically. HT, HL, and obesity are more prevalent in patients with a renal cyst when compared with patients without. Consequently, patients with a simple renal cyst should be evaluated and followed up in terms of atherosclerotic risk factors.  相似文献   
10.
A two factor three level factorial design was used to investigate the effects of carbopol and cationic hydrophilic polymers which have a common use in buccal drug formulations. Statistical models with interaction terms were derived to evaluate influence of carbopol (X1) and chitosan (X2) on tablet disintegration (Y1) and dissolution (Y2), mechanical properties (Y3), swelling (Y4). Tablet disintegration studies were carried out using two different pH environments within buccal region pH limits and also two different commonly used dissolution methods for buccal tablets were also investigated to compare the effect of polymer type on dissolution. Polymer type and ratio affect the characteristics of the buccal tablets due to their different physicochemical behavior at buccal pH. Also significant variances between dissolution profiles for buccal tablets, using either USP Paddle or flow through cell methods were found. These results indicate that both polymer type and ratio as well as combination of them effects the drug behavior in different ways.  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