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   399篇
  免费   21篇
  国内免费   4篇
儿科学   1篇
妇产科学   5篇
基础医学   29篇
口腔科学   49篇
临床医学   22篇
内科学   154篇
皮肤病学   6篇
神经病学   7篇
特种医学   15篇
外科学   36篇
综合类   5篇
预防医学   8篇
药学   12篇
肿瘤学   75篇
  2022年   6篇
  2021年   3篇
  2020年   4篇
  2019年   3篇
  2017年   5篇
  2016年   8篇
  2015年   6篇
  2014年   6篇
  2013年   11篇
  2012年   17篇
  2011年   20篇
  2010年   11篇
  2009年   10篇
  2008年   9篇
  2007年   14篇
  2006年   10篇
  2005年   18篇
  2004年   11篇
  2003年   17篇
  2002年   18篇
  2001年   11篇
  2000年   16篇
  1999年   17篇
  1998年   6篇
  1997年   5篇
  1995年   5篇
  1994年   5篇
  1993年   8篇
  1992年   11篇
  1991年   7篇
  1990年   15篇
  1989年   8篇
  1988年   4篇
  1987年   8篇
  1986年   7篇
  1985年   5篇
  1984年   4篇
  1983年   3篇
  1979年   3篇
  1976年   2篇
  1975年   3篇
  1974年   8篇
  1973年   5篇
  1972年   6篇
  1971年   6篇
  1970年   6篇
  1969年   10篇
  1968年   5篇
  1967年   2篇
  1966年   6篇
排序方式: 共有424条查询结果,搜索用时 15 毫秒
1.
A variant of the HL-60 cell line, HL-60/MCSFR4D2, has been found to express twice the amount of PTP1C as compared to the parental HL-60 cell line by immunoblotting and immunoprecipitation. Differentiation of the variant cells after phorbol 12-myristate 13-acetate (PMA) treatment was examined by the appearance of adherence. In 1% fetal calf serum (FCS), 20% of HL-60/MCSFR4D2 cells exhibited adherence after treatment with 0.5 ng/ml PMA for 48 h, 60% exhibited adherence after treatment with 1.0 ng/ml PMA and 80% exhibited adherence after treatment with 5.0 ng/ml PMA, while HL-60 cells exhibited only a slight response. Furthermore, antisense PTP1C oligonucleotides decreased the PMA-induced adherence of HL-60/MCSFR4D2 cells. These results suggest that the high-expression of PTP1C in HL-60 cells may be involved in the enhancement of susceptibility to macrophage-like differentiation by PMA.  相似文献   
2.
Percutaneous aspiration biopsy of the pancreas using a heparinized 22-gauge fine needle was performed under ultrasonic guidance in five patients with benign pancreatic diseases and in 18 patients with pancreatic cancer. Using a heparinized needle and syringe, it was possible to make good smears containing abundant tumor cells and to obtain small tissue specimens. Using egg albumin as binding material, a new cell-block technic was developed to conveniently obtain histologic specimens. In this way, a correct diagnosis was made cytologically in all 23 patients suspected of having a pancreatic malignancy. Histologic specimens were obtained in 22 (95.6%) our of 23 patients. A correct diagnosis was established histologically in all patients from whom histologic materials were obtained. This procedure thus has proved a very reliable method for diagnosing pancreatic cancer.  相似文献   
3.
PURPOSE: Increases in gene dosage through DNA amplification represents a common feature of many tumors and can result in the up-regulation of tumor-promoting genes. Our recent genome-wide, array-based comparative genomic hybridization analysis of 66 cases of diffuse large B-cell lymphoma found that genomic gain of 6p21 was observed in as many as 17 cases, including 14 cases with low-level copy number gain and three cases with high-level copy number gains (amplifications). EXPERIMENTAL DESIGN AND RESULTS: To identify the target gene(s) for 6p21 amplification, we constructed a detailed amplicon map at the region of genomic amplification with the aid of high-resolution contig array-based comparative genomic hybridization glass slides, consisting of contiguously ordered bacterial artificial chromosome/P1-derived artificial chromosome clones covering 3 Mb throughout the 6p21 amplification region. Alignment of the amplifications identified a minimally overlapping 800 kb segment containing 15 genes. Quantitative expression analysis of the genes from both patient samples and the SUDHL9 cell line revealed that CCND3 and BYSL (1.9 kb telomeric to the CCND3 gene locus) are the targets of 6p21 genomic gain/amplification. CONCLUSIONS: Although it is known that t(6;14)(p21;q32) induces aberrant overexpression of CCND3 in B-cell malignancies, we were able to show that CCND3, which encodes the cyclin D family member protein that controls the G1-S phase of cell cycle regulation, can also be a target of genomic gain/amplification. Overexpression of CCND3 through genomic amplification is likely to lead to aberrant cell cycle control, although the precise biological role of BYSL with respect to tumorigenesis remains to be determined.  相似文献   
4.
The aim of this multicentre study was to investigate the effect of prosthetic restoration for missing posterior teeth on mastication in patients with shortened dental arches (SDAs). Partially dentate patients who had an intact teeth in anterior region and missed distal molar(s) (2–12 missing occlusal units) classified as Kennedy Class I or Class II were recruited from seven university‐based dental hospitals in Japan. Of the 125 subjects who underwent baseline (pre‐treatment) and follow‐up/post‐treatment evaluation, 53 chose no replacement of missing teeth and 72 chose treatment with removable partial dentures (n = 53) or implant‐supported fixed partial dentures (n = 19). Objective masticatory performance (MP) was evaluated using a gummy jelly test. Perception of chewing ability (CA) was rated using a food intake questionnaire. In the no‐treatment group, mean MP and CA scores at baseline were similar to those at follow‐up evaluation (P > 0·05). In the treatment group, mean MP after treatment was significantly greater than the pre‐treatment mean MP (P < 0·05). However, the mean perceived CA in the treatment groups was similar at pre‐ and post‐treatment (P > 0·05). In a subgroup analysis of subjects in the treatment group, subjects with lower pre‐treatment CA showed a significant CA increase after treatment (P = 0·004), but those with higher pre‐treatment CA showed a significant decrease in CA (P = 0·001). These results suggest that prosthetic restoration for SDAs may benefit objective masticatory performance in patients needing replacement of missing posterior teeth, but the benefit in subjective chewing ability seems to be limited in subjects with perceived impairment in chewing ability before treatment.  相似文献   
5.
6.

Background

Endoscopic resection is recommended for rectal neuroendocrine tumors <?1 cm in diameter; the three techniques (mucosal resection, submucosal dissection, and mucosal resection with variceal ligation device) of endoscopic resection of neuroendocrine tumor were reported; however, the optimal endoscopic technique remains unclear.

Purpose

We compared the efficacy and safety of three endoscopic rectal neuroendocrine tumor resection methods.

Methods

We retrospectively enrolled 52 patients with rectal neuroendocrine tumors treated by endoscopy at Aichi Medical University Hospital and Nagoya City University Hospital between May 2003 and June 2017. We compared clinical outcomes in three groups based on the endoscopic treatment method.

Results

Fifty-two patients underwent endoscopic rectal neuroendocrine tumor treatment (mucosal resection, 14; submucosal dissection, 19; mucosal resection with an endoscopic variceal ligation device, 19). In the endoscopic mucosal resection, submucosal dissection, and mucosal resection with variceal ligation device groups, R0 resection occurred in 50.0, 94.7, and 89.5%, respectively (mucosal resection vs. mucosal resection with variceal ligation device, p <?0.05; mucosal resection vs. submucosal dissection, p <?0.01), while the median procedure times were 6.5, 43, and 6.0 min, respectively (submucosal dissection vs. mucosal resection with variceal ligation device procedure times, p?<?0.01; mucosal resection vs. submucosal resection procedure times, p <?0.01). Postoperative bleeding occurred after endoscopic mucosal resection (1/14) and endoscopic submucosal dissection (4/19), but not after endoscopic mucosal resection with a ligation device.

Conclusion

Endoscopic mucosal resection with an endoscopic variceal ligation device was a safe, effective treatment for rectal neuroendocrine tumors.
  相似文献   
7.
8.
Summary We report pathological findings of the aortic homograft in a 27-year-old patient who died 20 years after implantation at the time of correction of tetralogy of Fallot. Although calcification of the homograft was severe with degeneration of valve leaflets, no functional obstruction of the homograft was found as a conduit. This observation may suggest a beneficial aspect of the aortic homograft as the right ventricle to the pulmonary artery conduit late after corrective surgery even if calcification was not avoided.  相似文献   
9.
Ultrasonography should be used for screening of hepatocellular carcinoma, but there are few reports on the relationship between liver ultrasonographic findings and the development of hepatocellular carcinoma (HCC). Using prospective follow-up studies, we examined the role of liver with a hypoechoic nodular pattern as a high-risk factor in HCC. The study was performed by follow-up on 593 patients with chronic liver disease recorded at our hospital. The ultrasonographic pattern of the liver parenchyma was classified either as a small or large hypoechoic nodular pattern or as a nonnodular pattern. Patients were followed up from the time of initial ultrasonographic examination (1985–1987) until January 1, 1991. During the follow-up period (average, 4.2 years, range, 0.3–6.0 years), 62 patients were found to have HCC (12%). Patients whose livers showed small or large hypoechoic nodular pattern had a significantly higher risk of HCC than did patients whose livers showed a nonnodular pattern (rate ratios were 14.0 and 20.0, respectively, adjusted for age, sex, hepatitis virus markers, ICG R15, α-fetoprotein concentration, and ultrasonographic pattern of the liver). Liver showing a hypoechoic nodular pattern is a major risk factor in HCC.  相似文献   
10.
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