全文获取类型
收费全文 | 1359476篇 |
免费 | 101605篇 |
国内免费 | 4406篇 |
专业分类
耳鼻咽喉 | 17075篇 |
儿科学 | 44249篇 |
妇产科学 | 37133篇 |
基础医学 | 200395篇 |
口腔科学 | 36521篇 |
临床医学 | 131436篇 |
内科学 | 263914篇 |
皮肤病学 | 26927篇 |
神经病学 | 114421篇 |
特种医学 | 49226篇 |
外国民族医学 | 370篇 |
外科学 | 187685篇 |
综合类 | 28896篇 |
现状与发展 | 1篇 |
一般理论 | 465篇 |
预防医学 | 115680篇 |
眼科学 | 29457篇 |
药学 | 100033篇 |
6篇 | |
中国医学 | 3182篇 |
肿瘤学 | 78415篇 |
出版年
2021年 | 11397篇 |
2019年 | 12050篇 |
2018年 | 16835篇 |
2017年 | 12679篇 |
2016年 | 13784篇 |
2015年 | 15724篇 |
2014年 | 21569篇 |
2013年 | 33069篇 |
2012年 | 45725篇 |
2011年 | 48378篇 |
2010年 | 28097篇 |
2009年 | 25943篇 |
2008年 | 44237篇 |
2007年 | 46395篇 |
2006年 | 46587篇 |
2005年 | 44908篇 |
2004年 | 42837篇 |
2003年 | 40689篇 |
2002年 | 39380篇 |
2001年 | 61187篇 |
2000年 | 62848篇 |
1999年 | 52636篇 |
1998年 | 14831篇 |
1997年 | 13544篇 |
1996年 | 13286篇 |
1995年 | 12659篇 |
1994年 | 11782篇 |
1993年 | 11090篇 |
1992年 | 41839篇 |
1991年 | 41008篇 |
1990年 | 39694篇 |
1989年 | 37555篇 |
1988年 | 34778篇 |
1987年 | 33894篇 |
1986年 | 32362篇 |
1985年 | 30823篇 |
1984年 | 23209篇 |
1983年 | 19734篇 |
1982年 | 11883篇 |
1979年 | 20951篇 |
1978年 | 14924篇 |
1977年 | 12175篇 |
1976年 | 11976篇 |
1975年 | 12204篇 |
1974年 | 14923篇 |
1973年 | 14573篇 |
1972年 | 13456篇 |
1971年 | 12493篇 |
1970年 | 11547篇 |
1969年 | 10475篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
961.
Christopher D Gardner James L Zehnder Alison J Rigby Joel R Nicholus John W Farquhar 《Blood coagulation & fibrinolysis》2007,18(8):787-793
Several case reports have implicated Ginkgo biloba in clinically adverse bleeding disorders. Ginkgo biloba has been reported to increase pain-free walking distance among patients with peripheral artery disease (PAD). Standard PAD therapy includes 325 mg/day aspirin. The objective of this study was to examine potential adverse effects of concomitant aspirin and Ginkgo biloba on platelet function. Ginkgo biloba (EGb 761, 300 mg/day) was compared with placebo for effects on measures of platelet aggregation among adults consuming 325 mg/day aspirin in a randomized, double-blind, placebo-controlled, parallel design trial of 4-week duration. Participants were adults, age 69 +/- 10 years, with PAD or risk factors for cardiovascular disease. Outcome measures included platelet function analysis (PFA-100 analyzer) using ADP as an agonist (n = 26 placebo; n = 29 ginkgo), and platelet aggregation using ADP, epinephrine, collagen and ristocetin as agonists (n = 21 placebo; n = 23 ginkgo). Participants kept daily logs of bleeding or bruising episodes. There were no clinically or statistically significant differences between treatment groups for any agonists, for either PFA-100 analysis or platelet aggregation. Reports of bleeding or bruising were infrequent and similar for both study groups. In conclusion, in older adults with PAD or cardiovascular disease risk, a relatively high dose of Ginkgo biloba combined with 325 mg/day daily aspirin did not have a clinically or statistically detectable impact on indices of coagulation examined over 4 weeks, compared with the effect of aspirin alone. No adverse bleeding events were observed, although the trial was limited to a small sample size. 相似文献
962.
C Diemunsch F Faure F Trunde L Morgon D Bossard M Jourlin J L Coudert F Disant 《Computer aided surgery》2007,12(5):262-269
Facial hemiatrophies are anomalies of the first branchial arch and affect one in 4000-5000 newborns. Bone distraction is the technique of choice for the treatment of these dysmorphoses. Mandibular osteodistraction requires prior determination of the characteristics of the distraction vector whose three components will serve to activate the distractor. The patient, aged 5 years, presented with a right facial hemiatrophy, Grade IB according to the classification of Pruzansky. Tomodensitometric acquisition was obtained with a CT scanner. Software specifically designed for this application allows segmentation of the anatomical elements by a region-growing algorithm. The 3D representation of each element is added to a 3D scene, in which are placed the built-up landmarks necessary for the surgical simulation after 3D cephalometric analysis. The surgical cleavage plane is oriented according to the surgeon's requirements while preserving the predominant anatomical elements. The software allows performance of rotations and translations of the bone segments rendered independently from the cleavage plane. The distances and angles covered during the virtual movement are measured at its conclusion. The aim of moving the bone segments is to render the mandibular occlusion plane parallel to the reference occlusion plane. The vertical growth of the maxilla is realized by secondary recuperation. The distractor used was of an external multidirectional type allowing elongation of the mandibular ramus and mandibular corpus, closure of the goniac angle, and lateralization or medialization of the ramus. On the 15th day, the mandibular angle was reduced by 10 degrees, which allowed closure of the anterior gap and recentering of the incisive areas by a half-cuspid. The patient presented with a complex bone deficit in the three spatial directions, which allowed the development of software for modeling the distraction. Other clinical cases will be necessary to validate this 3D imaging-based technique. 相似文献
963.
964.
965.
L Crespo J Graus F García-Hoz R Bárcena L Gil Grande V F Moreira J M Milicua J Sánchez J Blázquez 《Revista española de enfermedades digestivas》2007,99(11):667-670
Hepatic encephalopathy is a reversible state of altered cognition that may occur in patients with acute or chronic liver disease or porto-systemic shunt, and in which known neurological or psychiatric signs may develop. Nitrogenated substances from intestinal digestion reach the brain without being cleared by their passage through the liver due to the presence of porto-systemic shunt. We report two cases of patients with porto-systemic shunt diagnosed with recurrent chronic hepatic encephalopathy refractory to conventional medical treatment. They were satisfactorily treated with shunt embolization using interventionist radiology techniques. 相似文献
966.
E. Drakaki E. Borisova M. Makropoulou L. Avramov A. A. Serafetinides I. Angelov 《Skin research and technology》2007,13(4):350-359
BACKGROUND/PURPOSE: Laser-induced autofluorescence spectroscopy provides excellent possibilities for medical diagnostics of different tissue pathologies including cancer. However, to create the whole picture of pathological changes, investigators collect spectral information from patients in vivo or they study different tumor models to obtain objective information for fluorescent properties of every kind of healthy and diseased tissue. Therefore, it is very important to find the most appropriate, and close to the human skin, animal samples from the fluorescence point of view, which will allow the extrapolation of the animal data to human spectroscopic diagnostics. METHODS: In the present work, we examined the autofluorescence properties of different animal skin tissues, which are considered as the most common skin models. A nitrogen laser was used as an excitation source. Samples of healthy mouse, chicken and pig skin in vivo and/or ex vivo were studied and were compared with results obtained from investigations of healthy human skin in vivo. RESULTS AND CONCLUSION: Specific features of the recorded spectra are discussed and the possible origin of the obtained fluorescence signals is proposed. Quantitative evaluation of data extrapolation for each skin type is also depicted. 相似文献
967.
L. C. Teoh 《ANZ journal of surgery》2007,77(Z1):A35-A35
The severely of skin loss and the options of resurfacing is determined by taking into account the following factors. 1) The size & location of the defect, 2) The depth of the defect and the quality of the tissue bed, 3) The extent of exposed vital structures, 4) The associated bone and other tissues injuries, 5) The availability of donor skin flap. The size of the defect is the most important factor in choosing a resurfacing option. The size can be categorized into small, medium and large. A small defect is one that is less than 5 cm2 in size, a medium defect is between 5 to 15 cm2, and a large defect is greater than 15 cm2. Local flaps are usually sufficient to cover small defects <5 cm2. These are advancement flaps or rotation and transposition flaps. Regional flaps are indicated to resurface these medium‐sized defects 5 to 15 cm2. The donor is within the same region of the hand, from one of the digits or from dorsum and palmar surfaces of the hand. It is usually based on vascular or NV pedicles. Large defects >15 cm2 will need larger flaps for coverage. These large flaps are pedicled distant flaps and free flaps. In these severe injuries, there is usually associated bone and soft tissues injuries. These injuries can be reconstructed as a single stage combined reconstruction or multi‐staged reconstructions. The resurfacing should always be given priority. 相似文献
968.
A K Burroughs L Marelli E Cholongitas P Manousou K Rolles V Karam V Delvart R Adam C Sabin 《Liver transplantation》2007,13(6):935-6; author reply 937
969.
Quantification of Basal and Stimulated ROS Levels as Predictors of Islet Potency and Function 总被引:2,自引:0,他引:2
B. Armann M. S. Hanson E. Hatch A. Steffen L. A. Fernandez 《American journal of transplantation》2007,7(1):38-47
We have developed a luminol-based assay using intact islets, which allows for quantification of reactive oxygen species (ROS). In addition, an index capable of characterizing metabolic and mitochondrial integrity prior to transplantation was created based on the capacity of islets to respond to high glucose and rotenone (mitochondrial respiratory chain complex I inhibitor) by production of ROS. To validate this assay, lipid peroxidation and antioxidative defense capacity were evaluated by detection of malondialdehyde (MDA) levels and glutathione peroxidase activity (GPx), respectively. Also, flow cytometric analyses of ROS (dihydroethidine), apoptosis (Annexin V, active caspases), necrosis (Topro3), and mitochondrial membrane potential (JC-1) were done in parallel to correlate with changes in luminol-measured ROS. ATP/ADP ratios were quantified by HPLC and the predictive value of ROS measurement on islet functional potency was correlated with capacity to reverse diabetes in a streptozotocin-induced diabetic NOD.scid mouse model as well as in human transplant recipients. Our data demonstrate that levels of ROS in islets correlate with the percentage of apoptotic cells and their functional potency in vivo. The ROS indices following glucose and rotenone exposure are indicative of metabolic potency and mitochondrial integrity and can be used as surrogate markers to evaluate the quality of islets prior to transplantation. 相似文献
970.
G. Y. Meyer‐Rochow A. J. Gill L. W. Delbridge S. B. Sidhu M. S. Sywak 《ANZ journal of surgery》2007,77(Z1):A22-A22
Purpose Parathyroid carcinoma (PC) is rare and accounts for less than 1% of all cases of primary hyperparathyroidism (PHPT). The definitive histopathologic diagnosis of PC requires unequivocal invasion or metastasis which may be absent at first presentation. As a result, many cases of PC can only be diagnosed retrospectively. Parafibromin is the protein encoded by HRPT2 which is mutated and not expressed in many parathyroid carcinomas. Given that PCs generally weigh more than parathyroid adenomas (PA)s, we hypothesized that amongst large PAs there may be a high incidence of occult PC which could be identified by negative staining for parafibromin. Methodology 57 parathyroid glands weighing greater than 2 grams excised from 1998–2006 were identified from the University of Sydney Endocrine Surgical Database. Two specimens with a histopathologic diagnosis of PC were excluded. Immunohistochemical staining for parafibromin was performed on the remaining 55 PAs. Results Of the 55 specimens stained for parafibromin only one definite negative stain was detected. This case was originally classified as an “atypical adenoma” because it showed nuclear and architectural atypia without unequivocal evidence of invasive growth. In view of the negative staining for parafibromin it therefore probably represents occult carcinoma. There has been no evidence of recurrence or metastasis after 6.5 years. Conclusions Complete loss of staining for parafibromin is very rare in giant parathyroid adenomas suggesting that occult carcinoma is equally rare. As a result routine immunohistochemical staining for parafibromin does not appear to be an effective screening test for carcinoma in large PA without histopathologic features of PC. 相似文献