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   525篇
  免费   26篇
  国内免费   2篇
耳鼻咽喉   2篇
儿科学   20篇
妇产科学   6篇
基础医学   104篇
口腔科学   14篇
临床医学   38篇
内科学   124篇
皮肤病学   2篇
神经病学   68篇
特种医学   17篇
外科学   35篇
综合类   1篇
预防医学   32篇
眼科学   17篇
药学   46篇
肿瘤学   27篇
  2022年   5篇
  2021年   10篇
  2020年   6篇
  2019年   13篇
  2018年   16篇
  2017年   13篇
  2016年   17篇
  2015年   11篇
  2014年   25篇
  2013年   22篇
  2012年   27篇
  2011年   38篇
  2010年   19篇
  2009年   13篇
  2008年   22篇
  2007年   32篇
  2006年   21篇
  2005年   32篇
  2004年   21篇
  2003年   26篇
  2002年   33篇
  2001年   8篇
  2000年   6篇
  1999年   6篇
  1998年   3篇
  1997年   5篇
  1996年   13篇
  1995年   7篇
  1994年   3篇
  1993年   7篇
  1992年   3篇
  1991年   3篇
  1990年   5篇
  1989年   4篇
  1988年   4篇
  1985年   2篇
  1984年   3篇
  1983年   3篇
  1982年   3篇
  1981年   5篇
  1980年   4篇
  1979年   2篇
  1978年   3篇
  1975年   2篇
  1974年   2篇
  1973年   2篇
  1972年   2篇
  1971年   2篇
  1970年   2篇
  1969年   4篇
排序方式: 共有553条查询结果,搜索用时 8 毫秒
101.

Objectives

The major objective was to prospectively compare the grade of bowel distension obtained with four different computed tomography (CT) techniques dedicated for the examination of the small intestine (CT enteroclysis [CTE] and enterography [CTe]), of the colon (CT with water enema [CT-WE]), or both (CTe with water enema [CTe-WE]). The secondary objective was to assess patients’ tolerance toward each CT protocol.

Materials and methods

Recruitment was designed to obtain four groups of the same number of patients (30). Each group corresponded to a specific CT technique, for a total of 120 consecutive outpatients (65 male and 55 female, mean age 51.09 ± 13.36 years).CTE was performed after injection of methylcellulose through a nasojejunal tube, while in the CTe protocol a polyethylene glycol electrolyte solution was orally administered to patients prior to the CT acquisition. In the CT-WE protocol intraluminal contrast (water) was administered only by a rectal enema, while CTe-WE technique included both a rectal water enema and oral ingestion of neutral contrast material to obtain a simultaneous distension of small and large bowel.CT studies were reviewed in consensus by two gastrointestinal radiologists who performed a quantitative and qualitative analysis of bowel distension on a per segment basis. The presence and type of adverse effects were recorded.

Results

CTE provided the best distension of jejunal loops (median diameter 27 mm, range 17–32 mm) when compared to all the other techniques (p < 0.0001). The frequency of patients with an adequate distension of the terminal ileum was not significantly different among the four groups (p = 0.0608). At both quantitative and qualitative analysis CT-WE and CTe-WE determined a greater and more consistent luminal filling of the large intestine than that provided by both CTE and CTe (p < 0.0001 for all colonic segments). Adverse effects were more frequent in patients belonging to the CTE group (p < 0.0028).

Conclusions

CTE allows an optimal distension of jejunal loops, but it is the most uncomfortable CT protocol. When performing CT-WE, an adequate retrograde distension of the terminal ileum was provided in a particularly high percentage of patients. CTe-WE provides a simultaneous optimal distension of both small and large bowel.  相似文献   
102.
NK cells use a variety of receptors to detect abnormal cells, including tumors and their metastases. However, in the case of melanoma, it remains to be determined what specific molecular interactions are involved and whether NK cells control metastatic progression and/or the route of dissemination. Here we show that human melanoma cell lines derived from LN metastases express ligands for natural cytotoxicity receptors (NCRs) and DNAX accessory molecule-1 (DNAM-1), two emerging NK cell receptors key for cancer cell recognition, but not NK group 2 member D (NKG2D). Compared with cell lines derived from metastases taken from other anatomical sites, LN metastases were more susceptible to NK cell lysis and preferentially targeted by adoptively transferred NK cells in a xenogeneic model of cell therapy. In mice, DNAM-1 and NCR ligands were also found on spontaneous melanomas and melanoma cell lines. Interference with DNAM-1 and NCRs by antibody blockade or genetic disruption reduced killing of melanoma cells. Taken together, these results show that DNAM-1 and NCRs are critical for NK cell–mediated innate immunity to melanoma cells and provide a background to design NK cell–based immunotherapeutic strategies against melanoma and possibly other tumors.  相似文献   
103.
104.
We analyzed gastrin, PTH, and calcitonin responses to oral calcium and peptones in hypocalciuric hypercalcemia, mild primary hyperparathyroidism, and normal controls. We observed diverse hormonal responses that may help in the differential diagnosis of these conditions. INTRODUCTION: Hypocalciuric hypercalcemia (HH) is consequent to calcium-sensing receptor (CaSR) genetic mutations or anti-CaSR antibodies. CaSR is expressed in parathyroid tissue, thyroid C cells, and gastrin-secreting cells, where it has been suggested that on calcium and/or amino acid allosteric activation, promotes gastrin secretion. MATERIALS AND METHODS: We evaluated gastrin, PTH, and calcitonin responses to oral calcium (1 g) and peptones (10 g) in 10 patients with HH (mean age, 58.5 +/- 10.3 years; F/M = 9/1), 15 patients with primary hyperparathyroidism (PH; mean age, 60.4 +/- 8.3 years; F/M = 11/4), and 30 healthy controls (mean age, 60.3 +/- 8.1 years). Statistical analyses for differences during oral loading tests were calculated with ANOVA for repeated measurements and comparisons between two groups were performed with Student's t-test. RESULTS: PTH response to peptones was markedly increased in patients with PH compared with flat responses in controls and HH patients (p < 0.05). Gastrin increase after oral calcium was absent in HH and PH subjects (p < 0.05 versus controls), and gastrin responses to peptones were blunted in HH and PH subjects compared with controls (p < 0.05). PTH drop and calcitonin increase after calcium load observed in controls were absent in HH and PH subjects (p < 0.05). CONCLUSIONS: The marked difference in PTH response elicited by peptones observed in PH compared with subjects with HH may help in the differential diagnosis of these conditions without genetic studies. Peptones may stimulate CaSR-controlled hormones as an allosteric regulatory pathway. CaSR abnormalities may help to explain the different calcium- and peptones-induced hormonal responses observed in PH and HH compared with normal subjects.  相似文献   
105.
106.
The present paper revies the theoretical formulations of behavior analysis as applied to students with behavior disorders and emotional disturbance. The major proponents of this approach are presented along with the characteristics of the behavioral approach. A discussion of a functional analysis as the methodology for understanding the possible etiology and maintenance of problem behavior is presented. Advances in cognitive behavior modification are presented.  相似文献   
107.
Summary The effect of reduced glutathione on acute lethal toxicity and urotoxicity induced by cyclophosphamide was studied on both mice and rats. The results of this investigation indicate that reduced glutathione is an effective protective agent against bladder damage from treatment with the alkylating agent. The timing of glutathione administration (IV) with respect to cyclophosphamide treatment influenced the uroprotective efficacy of the thiol compound. A schedule-dependent protective effect of glutathione against acute lethal toxicity of the antitumor drug was also observed. This partial protection was accompanied by a reduction in body weight loss following cyclophosphamide treatment. The therapeutic activity of cyclophosphamide on two experimental tumor systems (L1210 and Gross leukemia) was not impaired by combined treatment with glutathione, even at a relatively high dose of glutathione compared with cyclophosphamide.  相似文献   
108.
BACKGROUND: Solitary fibrous tumor (SFT) is a rare spindle cell tumor that arises most often in the visceral pleura; however, a review of the literature shows at least 31 cases occurring in the orbit. METHODS: A retrospective case series of three patients with orbital SFT: a 50-year-old man, observed in 1997, with an angioma-like lesion in the upper half of the orbit causing osteolysis of the orbital roof; a 24-year-old man, observed in 1992, with a superotemporal mass in the right orbit occupying the lacrimal gland region, firstly diagnosed as schwannoma, recurring 4 years after dacryoadenectomy; a 70-year-old man, with a retrobulbar mass diagnosed on a biopsy as hemangiopericytoma, recurring and infiltrating the orbital roof 4 years after surgery. RESULTS: A review of the literature and presentation of three cases of SFT which showed infiltration of the orbital roof and/or recurrence. CONCLUSIONS: Our cases provide evidence of how orbital SFT can behave aggressively and mimic other orbital tumors, thus making mandatory the consideration of this relatively new entity in common clinical practice as well as careful follow-up. Their aggressive growth is unusual, described in only 6 of the 31 cases so far reported in the literature. Immunohistochemistry is of importance for the diagnosis, since CD34 immunoreactivity is peculiar to SFT.  相似文献   
109.
110.
Abstract The number of women who decide to have a child after organ transplantation has increased. We determined the outcomes of 67 pregnancies of women who had undergone kidney, liver or heart transplantation. All recipients had been maintained on immunosuppressive therapy before and during pregnancy. Pregnancy complications at term were observed in 17 out of 67 women (25%), hypertension being the most frequent complication (16.17%). Two transplant rejections were reported. Sixty-eight infants were delivered (including one pair of twins); five women had two pregnancies at term. Twenty-eight miscarriages (29.2%) were recorded. Of these 68 babies (including the pair of twins), 40 (58.8%) were born at term and 28 (41.2%) before term. The babies were followed-up for 2 months to 13 years. According to our previous experience, our study shows that patients who have undergone organ transplantation can give birth to healthy infants as long as they are monitored accurately during pregnancy.  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