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   1054篇
  免费   30篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   23篇
妇产科学   17篇
基础医学   105篇
口腔科学   55篇
临床医学   64篇
内科学   240篇
皮肤病学   14篇
神经病学   100篇
特种医学   47篇
外科学   169篇
综合类   2篇
预防医学   40篇
眼科学   5篇
药学   64篇
肿瘤学   138篇
  2023年   10篇
  2022年   21篇
  2021年   20篇
  2020年   9篇
  2019年   13篇
  2018年   19篇
  2017年   14篇
  2016年   13篇
  2015年   8篇
  2014年   21篇
  2013年   20篇
  2012年   45篇
  2011年   58篇
  2010年   37篇
  2009年   32篇
  2008年   43篇
  2007年   63篇
  2006年   43篇
  2005年   46篇
  2004年   50篇
  2003年   48篇
  2002年   43篇
  2001年   40篇
  2000年   45篇
  1999年   45篇
  1998年   13篇
  1997年   5篇
  1996年   6篇
  1995年   10篇
  1994年   11篇
  1993年   4篇
  1992年   24篇
  1991年   27篇
  1990年   28篇
  1989年   28篇
  1988年   19篇
  1987年   9篇
  1986年   11篇
  1985年   15篇
  1984年   8篇
  1982年   3篇
  1981年   6篇
  1980年   5篇
  1979年   8篇
  1976年   5篇
  1975年   5篇
  1973年   3篇
  1971年   5篇
  1970年   3篇
  1969年   4篇
排序方式: 共有1085条查询结果,搜索用时 15 毫秒
91.

Background/Purpose

The proximal jejunal vein which branches from the dorsal side of the superior mesenteric vein (SMV) usually drains the inferior pancreatoduodenal veins (IPDVs) and contacts the uncinate process of the pancreas. We focused on this vein, termed the proximal dorsal jejunal vein (PDJV), and evaluated the anatomical classification of the PDJV and surgical outcomes in patients with pancreatic ductal adenocarcinoma (PDAC) with PDJV involvement (PDJVI).

Methods

The jejunal veins that branch from the dorsal side of the SMV above the inferior border of the duodenum are defined as PDJVs. We investigated 121 patients who underwent upfront pancreaticoduodenectomy for PDAC between 2011 and 2017; PDJVs were resected in all patients. The anatomical classification of PDJV was evaluated using multidetector computed tomography. Surgical and prognostic outcomes of pancreticoduodenectomy for PDAC with PDJVI were evaluated.

Results

The PDJVs were classified into seven types depending on the position of the first and second jejunal veins relative to the superior mesenteric artery. In all patients, the morbidity and mortality rates were 15.7 and 0.8%, respectively. The rates for parameters including SMV resection, presence of pathological T3–4, R0 resection, and 3-year survival were 46.2, 92.3, 92.3, and 61.1%, respectively, when there was PDJVI (n?=?13). When there was no PDJVI (n?=?108), the rates were 60.2, 93.5, 86.1, and 58.3%, respectively. Overall, there were no significant differences.

Conclusions

Pancreaticoduodenectomy with PDJV resection is feasible for PDAC with PDJVI and satisfactory overall survival rates are achievable. It may be necessary to reconsider the resectability of PDAC with PDJVI.
  相似文献   
92.
93.
Congenital lipoid adrenal hyperplasia (CLAH) is an autosomal recessive disorder characterized by impaired synthesis of adrenal and gonadal steroids. It was demonstrated that loss-of-function mutations in the steroidogenic acute regulatory protein (StAR) gene cause CLAH and that 46,XX patients with CLAH develop spontaneous puberty. We had reported that three 46,XX patients with CLAH had presented spontaneous puberty and one of the patients had developed life-threatening ovarian cysts, before the etiology of CLAH had been clarified. In the present study, we analyzed their StAR gene and demonstrated mutations. Endocrinological examinations of the patients revealed that serum LH and FSH levels and their responses to the LHRH stimulation were not exaggerated before the onset of puberty. Serum LH levels and its response to LHRH were increased during puberty, whereas serum FSH levels remained within the normal range. Serum estradiol increased after the administration of human menopausal gonadotropins in the pubertal patient, suggesting that the ovary might have another system than StAR to facilitate cholesterol transport into the mitochondria. Although the patients had menstrual cycles, they remained anovulatory, and the resultant increased secretion of LH was speculated to be responsible for the development of ovarian cysts.  相似文献   
94.
95.
Systemic sclerosis (SSc) is a chronic disease of unknown etiology that is characterized by multiple tissue fibrosis. Transforming Growth Factor-beta (TGF-β) is thought to be the most important mediator that induces fibrosis. However, the molecular mechanisms by which fibrosis is induced have not been fully elucidated. In this study, the role of activin, a member of the TGF-β superfamily, was investigated in the pathogenesis of fibrosis in SSc. Serum activin A levels in patients with SSc were measured by ELISA, and the expression of the activin receptor type IB (ACVRIB/ALK4) and the activity of the signaling pathway via ACVRIB/ALK4 were investigated using western blotting. To evaluate a potential therapeutic strategy for SSc, we also attenuated the ACVRIB/ALK4 pathway using an inhibitor. Serum activin A levels were significantly higher in SSc patients than in normal controls. Activin A and ACVRIB/ALK4 expression were also higher in cultured SSc fibroblasts. Activin A stimulation induced phosphorylation of Smad2/3 and CTGF expression in SSc fibroblasts. Procollagen production and Col1α mRNA also increased upon stimulation by activin A. The basal level of Smad2/3 phosphorylation was higher in cultured SSc fibroblasts than in control cells, and treatment with the ALK4/5 inhibitor SB431542 prevented phosphorylation of Smad2/3 and CTGF expression. Furthermore, production of collagen was also induced by activin A. Activin A-ACVRIB/ALK4-Smad-dependent collagen production was augmented in SSc fibroblasts, suggesting the involvement of this signaling mechanism in SSc. Inhibition of the activin A-ACVRIB/ALK4-Smad pathway would be a new approach for the treatment of SSc.  相似文献   
96.
Previously, we have reported that a serial passage of 83P-5 strain of porcine epidemic diarrhea virus (PEDV) in Vero cells resulted in a growth adaptation of the virus in cultured cells at the 22nd passage. In this study, we further maintained the 83P-5 in Vero cells up to the 100th passage and analyzed changes in the spike (S), membrane (M), and nucleocapsid (N) gene sequences and pathogenicity of the virus at the 34th, 61st, and 100th passage levels. Sequence analyses revealed a strong selection for the S gene of 83P-5 in Vero cells, and virtually all mutations occurring at the 34th and 61st passages had been carried over to the 100th-passaged virus. In contrast, the viral M and N genes showed a strong conservation during the serial passage. Pigs experimentally infected with the 34th- or 61st-passaged virus, but not the 100th-passaged virus, exhibited diarrhea, indicating an attenuation of the 83P-5 at the 100th passage. Interestingly, S protein of the attenuated 100th-passaged 83P-5 showed a remarkable sequence similarity to that of previously reported DR-13 strain of attenuated PEDV that also had been established by serial passage in Vero cells. Further studies will be required to define whether the mutations in the S gene of 83P-5 that had been selected and accumulated during the serial passages are indeed the causalities of the growth adaptation in vitro and the attenuation of virulence in vivo.  相似文献   
97.
This study examined postmenopausal estrogen receptor-positive breast cancer patients who received prospective neoadjuvant endocrine therapy (NAET) with tamoxifen or anastrozole to determine if the 21-gene recurrence score (RS) predicts NAET responses. RS scores were determined from pretreatment core biopsy specimens. Although half of the specimens yielded insufficient RNA, the remaining samples were highly representative. Patients with a low RS tended to respond better than those with an intermediate or high RS (n = 43). Response rates by RS were similar between the tamoxifen and anastrozole groups. Patients with a low RS tended to have better relapse-free survival (RFS) than those with an intermediate or high RS (5y-RFS; 100% vs. 84% and 73%, respectively). These results suggest that RS predicts responses to NAET with tamoxifen or anastrozole. Because this pilot study examined a small sample size, these results should be validated in larger studies.  相似文献   
98.
OBJECTIVE: The objectives of this study were to investigate the prevalence of extracranial carotid plaque and the association between risk factors and carotid plaque in Japanese patients with ischemic stroke. METHODS: We consecutively recruited patients with ischemic stroke admitted to our hospital from January 2000 to September 2002. Neurologic signs and a brain magnetic resonance imaging diagnosed ischemic stroke. All subjects underwent a carotid ultrasonography. Multiple logistic regression analysis was used to determine the risk factors that independently contributed to the presence of carotid plaques. RESULTS: Carotid plaques were identified in 76.2% of the patients and bilateral plaques were found in 58.2%. These lesions were more frequent in comparison with previous Japanese reports. The risk factors that independently contributed to the presence of extracranial carotid plaques were hypertension, age, smoking and past history of ischemic stroke. CONCLUSIONS: This study demonstrates that extracranial carotid plaque is increasing in Japanese patients with ischemic stroke.  相似文献   
99.
We report a surgical case of severe left ventricular dysfunction due to cardiac sarcoidosis. A 45-year-old man who underwent pacemaker implantation for complete atrioventricular block was admitted to the hospital because of dyspnea due to congestive heart failure. Echocardiography revealed a left ventricular ejection fraction of 11%, with severe mitral insufficiency and thinning of the ventricular septum. He was successfully treated by anteroseptal ventricular exclusion, mitral and tricuspid annuloplasty, and bi-ventricular pacing. Postoperative pathologic study revealed noncaseating granulomas. The patient was referred to a cardiologist for further treatment with prednisone.  相似文献   
100.
This study was conducted to determine whether intercalated duct cells in the rat parotid gland have the properties of tissue stem cells. After induction of cellular proliferation by repeated administration of isoproterenol (IPR), a β-adrenergic agonist, proliferation activity in acinar, intralobular, and intercalated ductal cells was quantified using Ki-67 immunohistochemistry. The total number of each type of component cell in a gland was also estimated in the course of IPR treatment. IPR was found to induce proliferation of acinar and intercalated duct cells, but not intralobular duct cells. The total number of acinar cells in a gland on day 5 of IPR treatment was 1.6 times of that at day 0 (baseline). In contrast, the total numbers of intercalated and intralobular duct cells did not change from baseline, indicating a high possibility that the proliferated intercalated duct cells differentiated into acinar cells. On days 2 to 3 of IPR treatment, intercalated duct cells with amylase-positive secretory granules were recognized in a region very close to the acini, and were suspected of being transitional cells from intercalated duct to acinar cells. This quantitative study indicates that intercalated duct cells may have the properties of tissue stem cells upon IPR stimulation.  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