全文获取类型
收费全文 | 1789篇 |
免费 | 101篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 74篇 |
儿科学 | 72篇 |
妇产科学 | 74篇 |
基础医学 | 108篇 |
口腔科学 | 71篇 |
临床医学 | 154篇 |
内科学 | 486篇 |
皮肤病学 | 17篇 |
神经病学 | 91篇 |
特种医学 | 55篇 |
外科学 | 440篇 |
综合类 | 31篇 |
预防医学 | 44篇 |
眼科学 | 84篇 |
药学 | 49篇 |
中国医学 | 1篇 |
肿瘤学 | 67篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 17篇 |
2021年 | 31篇 |
2020年 | 23篇 |
2019年 | 35篇 |
2018年 | 51篇 |
2017年 | 36篇 |
2016年 | 70篇 |
2015年 | 119篇 |
2014年 | 108篇 |
2013年 | 122篇 |
2012年 | 147篇 |
2011年 | 155篇 |
2010年 | 89篇 |
2009年 | 69篇 |
2008年 | 146篇 |
2007年 | 156篇 |
2006年 | 137篇 |
2005年 | 139篇 |
2004年 | 120篇 |
2003年 | 69篇 |
2002年 | 45篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有1918条查询结果,搜索用时 651 毫秒
131.
Songur A Sarsilmaz M Sogut S Ozyurt B Ozyurt H Zararsiz I Turkoglu AO 《Progress in neuro-psychopharmacology & biological psychiatry》2004,28(4):693-698
Phospholipids located in the cellular membrane play a critical role in the fluid-mosaic model of membrane structure and membrane function. Evidence is mounting for the role of abnormal phospholipid metabolism in some neuropsychiatric disorders including schizophrenia. As an important essential fatty acid (EFA), omega-3 (omega-3) fatty acid series are found in large amounts in fish oil. The aim of this experimental study was to assess the changes of some of the oxidant and antioxidant parameters in the hypothalamus of rats fed with omega-3 EFA diet (0.4 g/kg/day) for 30 days. Eight control rats and nine rats fed with omega-3 were decapitated under ether anesthesia, and hypothalamus was removed immediately. Malondialdehyde (MDA) and nitric oxide (NO) levels as well as superoxide dismutase (SOD) and xanthine oxidase (XO) enzyme activities in the hypothalamus were measured. SOD activity was significantly decreased in omega-3 EFA treated group compared to control group (p < 0.014). Tissue MDA and NO levels were also decreased in omega-3 EFA treated group compared to control rats (p < 0.0001). Xanthine oxidase activity was found to be increased in omega-3 EFA treated rats when compared to the control group (p < 0.0001). Taken together, this preliminary animal study provides strong support for a therapeutic effect of omega-3 EFA in some neuropsychiatric disorders in which reactive oxygen species (ROS) are recently accused to be an important physiopathogenetic factor. 相似文献
132.
Cakmak SS Unlu MK Bilek B Buyukbayram H Sakalar YB 《Japanese journal of ophthalmology》2004,48(5):497-498
Background We report a case of inverted follicular keratosis (IFK) on the conjunctiva. A few cases of IFK have been reported in the literature, but it appears that IFK on the conjunctiva has never been reported.Case A 21-year-old man was referred for evaluation of a conjunctival mass.Observations By slit-lamp biomicroscopy, an 8 × 5 × 3mm mass was observed over the nasal conjunctiva adjacent to the limbus in the left eye. An excisional biopsy of the lesion was carried out. The results of a pathologic examination showed IFK. During the 9-month follow-up period, the patient had no recurrence of the lesion.Conclusion IFK can be considered in the differential diagnosis of conjunctival masses as a rare specific lesion. Jpn J Ophthalmol 2004;48:497–498 © Japanese Ophthalmological Society 2004 相似文献
133.
134.
Hemoglobins in unicellular organisms, like the one here in the bacterium Vitreoscilla, have greater chemical reactivity than their homologues in multicellular organisms. They can catalyze redox reactions and may protect cells against oxidative stress. The ability of Vitreoscilla hemoglobin to complement deficiencies of terminal cytochrome oxidases in Escherichia coli also suggests that this hemoglobin can receive electrons during respiration. In this study, a recombinant strain of Enterobacter aerogenes engineered to produce the Vitreoscilla Hb was investigated with regard to its susceptibility to oxidative stress. The culture response to oxidative stress produced by exogenously applied hydrogen peroxide was characterized in terms of cell growth, survival and the activities of two key antioxidant enzymes (catalase and superoxide dismutase). The influence of the physiological state of the cells and different media upon these culture dynamics was determined. Results showed that the hemoglobin-expressing strain is quite distinct in terms of growth/survival properties and activity of antioxidant enzymes from that of non-hemoglobin counterparts. 相似文献
135.
OBJECTIVES: Burkitt's lymphoma (BL) occurs mostly in children. Isolated bilateral ovarian involvement presenting with amenorrhea is extremely rare in young adults. CASE: A 24-year-old female presented with secondary amenorrhea. Bilateral adnexal masses were identified on physical examination and abdominal computed tomography (CT). She underwent total abdominal histerectomy and bilateral salpingoophorectomy. Histopathologic evaluation yielded a diagnosis of BL of ovaries. Combined chemotherapy was administered. After complete remission an autologous bone marrow transplantation (ABMT) was performed. She died 35 days after ABMT. CONCLUSIONS: Although rare, BL should be kept in mind when isolated ovarian tumors are detected in young patients. 相似文献
136.
Sendag F Itil IM Terek MC Yilmaz H 《The Australian & New Zealand journal of obstetrics & gynaecology》2002,42(4):359-362
OBJECTIVE: The aim of this study was to determine the changes in circulating T-cell subpopulations, B cells and natural killer cells in patients with imminent preterm labour. METHODS: Thirty-five pregnant patients with imminent preterm labour and 35 women with uncomplicated pregnancies were included in the study. The gestational ages of the patients ranged from 28 to 36 weeks in both groups. The specific lymphocyte antigens were detected using direct staining with monoclonal antibodies, and analysed by flow cytometry. RESULTS: We observed no significant difference in the mean percentage of T cell subpopulations, natural killer cells and active T cells in the group of patients with preterm labor when compared to controls. The mean percentage of T CD3+ lymphocytes was significantly lower and that of B CD19+ cells higher in the study group when compared to controls. CONCLUSION: The alterations in maternal circulating lymphocyte subpopulations could be associated with the mechanisms mediating preterm labour. 相似文献
137.
The risk of radiation-induced carcinogenesis after external beam radiotherapy of Graves' orbitopathy 总被引:3,自引:0,他引:3
PURPOSE: In order to estimate the risk of radiation-induced carcinogenesis after external beam radiotherapy of Graves' orbitopathy, we made dosimetric measurements with thermoluminescent dosimeters in a male Rando phantom using our treatment technique. METHODS: We produced dose-volume histograms from 5-mm CT slices using our treatment planning system. In this way we estimated the irradiation dose received by the main surrounding organs such as the brain, the bone and the eyeball. We use 6-MV X-ray for the treatment of Graves' orbitopathy and our total dose is 2,000 cGy, 200 cGy per fraction. Clinical target volume was limited to the retrobulbar orbital content and medial rectus muscle, sparing the lenses, lacrimal glands and the sella turcica. All dosimetric measurements with thermoluminescent dosimeters were made 3 times. RESULTS: We found that the dose to the right lens was 101.6 mGy and to left lens 103.4 mGy. Average absorbed doses to red bone marrow, thyroid, lung, esophagus, bone surface, skin and brain, respectively, were estimated to be 523, 21, 4, 5, 81, 29, 47 mGy. Then, using tissue weighting factors specified by the International Commission of Radiation Protection, the resulting total effective dose was calculated to be 66.8 mSv. CONCLUSION: The risk factor for fatal cancer development derived from human epidemiological data is presently assumed to be 10% per Gy. In patients treated by our method of retro-orbital external beam radiotherapy for Graves' orbitopathy, there is a 0.0067 (or 7 per 1,000 persons or 0.7%) risk of developing fatal radiation-induced cancer. 相似文献
138.
Giant-cell reparative granuloma (GCRG) occurs in the jaw, temporal bone, and short tubular bones of the hands and feet. Although GCRG can affect long bones, only small numbers of such cases have been sporadically reported. This report describes a giant-cell reparative granuloma in the proximal tibia in a 60-year-old woman, describes features of GCRG in long bones and reviews the literature. A 60-year-old female patient was referred to us with complaints of moderately tender swelling of the right leg. Whole-body scintigraphic scanning was performed, which incidentally also disclosed a distal femoral lesion. The patient was admitted for surgery and incisional biopsies were performed on both lesions. Pathology analysis of the specimen from the tibia showed new bone lamellae encircled by osteoblasts and multinucleated giant cells which were more numerous in the haemorrhagic regions of the stroma; the latter displayed fibroblasts, histiocytes and inflammatory cells. The specimen from the femoral lesion showed typical features of a benign enchondroma. The patient was readmitted for surgery. The femoral enchondroma was curetted and the cavity was packed with bone graft. The tibial GCRG was treated with marginal resection, autogenous and allogenous bone grafting and intramedullary nailing. Follow-up examination after two years showed no clinical or radiological evidence of a recurrence. Although GCRG is uncommon, it should be considered whenever a lucent, expansile, and possibly destructive lesion of a long bone is encountered. It should be distinguished from true giant cell tumours occurring in the same locations because they have different biologic behaviours. 相似文献
139.
Huseyin Eren Hasan Riza Aydin Levent Tumkaya Ilke Onur Kazaz Yildiray Kalkan Seher Nazli Kazaz 《Renal failure》2018,40(1):466-474
Purpose: This study investigated the antioxidant effects of whortleberry against cisplatin-induced nephrotoxicity in rats.Material and methods: This study included 48 female Sprague–Dawley rats weighing 263.68?±?8.29?g. The rats were divided into the following six groups, with eight rats in each group: control, ethanol control, whortleberry control, cisplatin control, 16?mg/kg cisplatin +100?mg/kg whortleberry, and 16?mg/kg cisplatin +200?mg/kg whortleberry groups. Biochemical analysis was performed by measuring total oxidant status and total antioxidant status, histopathological analysis was performed by calculating proximal and distal tubule areas (μm2), and immunohistochemical analysis was performed by determining anti-Caspase-3 immunostaining. Differences among the groups were examined using one-way analysis of variance, and p?.05 was considered statistically significant.Results: Cisplatin treatment decreased the total antioxidant status and increased the total oxidant status and Caspase-3 level. Moreover, it resulted in the dilatation, vacuolization and loss of tubular epithelial cells; and glomerular degeneration and edema in the kidney tissues (p?.05). Treatment with 100 and 200?mg whortleberries increased the total antioxidant status; decreased the total oxidant status and Caspase-3 level and ameliorated distal and proximal tubule degeneration, glomerular degeneration and edema in the kidney tissues (p?.05).Conclusions: Our results indicate that the antioxidant effects of the whortleberry decrease cisplatin-associated nephrotoxicity. 相似文献
140.
Ilknur Haberal Can MD Kursat Ceylan MD Muzaffer Caydere MD Ethem Erdal Samim MD Huseyin Ustun MD Durdu Sertkaya Karasoy 《Otolaryngology--head and neck surgery》2008,139(2):211-215
OBJECTIVES: To investigate the expression and clinical significance of MMP-2, MMP-7, MMP-9, and TIMP-1 in patients with nasal polyposis (NP) and chronic rhinosinusitis (CRS). STUDY DESIGN: Prospective study. SUBJECTS AND METHODS: This study involved 54 patients. There were three groups: nasal polyposis group, chronic rhinosinusitis group, and control group. Specimens were collected during endoscopic sinus surgery. Each sample was immunohistochemically examined. RESULTS: Expression of MMP-2 was found significantly increased in NP, whereas MMP-7 expression was found significantly increased in CRS (P < 0.001). TIMP-1 was significantly high in control group compared to CRS and NP (P < 0.001 and P = 0.002, respectively). CONCLUSIONS: Different regulation type of activation of MMPs has been found in these two diseases. If MMP-2 expression is intense in the mucosa, then this ends with polyp formation; if MMP-7 expression is intense, it ends with CRS or stays as CRS. 相似文献