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   2274篇
  免费   147篇
  国内免费   79篇
耳鼻咽喉   29篇
儿科学   120篇
妇产科学   17篇
基础医学   188篇
口腔科学   29篇
临床医学   233篇
内科学   698篇
皮肤病学   39篇
神经病学   151篇
特种医学   265篇
外科学   333篇
综合类   47篇
预防医学   74篇
眼科学   60篇
药学   90篇
中国医学   3篇
肿瘤学   124篇
  2023年   11篇
  2022年   19篇
  2021年   45篇
  2020年   27篇
  2019年   42篇
  2018年   56篇
  2017年   30篇
  2016年   35篇
  2015年   49篇
  2014年   86篇
  2013年   99篇
  2012年   118篇
  2011年   118篇
  2010年   76篇
  2009年   71篇
  2008年   104篇
  2007年   137篇
  2006年   101篇
  2005年   95篇
  2004年   91篇
  2003年   97篇
  2002年   75篇
  2001年   30篇
  2000年   33篇
  1999年   40篇
  1998年   62篇
  1997年   49篇
  1996年   66篇
  1995年   56篇
  1994年   45篇
  1993年   56篇
  1992年   24篇
  1991年   38篇
  1990年   32篇
  1989年   40篇
  1988年   43篇
  1987年   56篇
  1986年   37篇
  1985年   36篇
  1984年   20篇
  1983年   16篇
  1982年   14篇
  1981年   26篇
  1980年   22篇
  1979年   9篇
  1978年   13篇
  1977年   17篇
  1976年   10篇
  1975年   9篇
  1970年   3篇
排序方式: 共有2500条查询结果,搜索用时 0 毫秒
1.
The authors present a case of amyloid infiltration involving the trigeminal nerve that mimicked a malignant cavernous sinus tumor with perineural tumor infiltration. A 64-year-old man presented with trigeminal nerve numbness. Imaging revealed a plaque-like enhancing lesion along the right lateral cavernous sinus extending anteriorly into Meckel's cave and involving the proximal V2 and V3 branches of the trigeminal nerve. The patient underwent an extradural frontotemporal craniotomy with middle fossa exposure of the cavernous sinus to diagnose and treat the presumed malignant cavernous sinus tumor. A reddish mass involving the lateral dural wall of the cavernous sinus was resected. The gasserian ganglion, V2, and V3, the latter of which was biopsied, were enlarged. Permanent histopathological studies showed microscopic eosinophilic, amorphous material, which stained positive for Congo red, and an absence of neoplastic cells. The final diagnosis was amyloidoma. Thus, amyloidomas can involve the trigeminal nerve or ganglia and should be considered in the differential diagnosis of a cavernous sinus lesion mimicking a tumor. Patients may have symptomatic improvement of trigeminal neuropathy with resection of the amyloidoma outside the nerve capsule that is compressing the nerve, while resection of the lesion from within the capsule may result in permanent trigeminal nerve dysfunction.  相似文献   
2.
3.
OBJECTIVES: To test a possible association between the educational level (EL), cognitive performance, and neuropsychiatric features in Parkinson disease (PD). BACKGROUND: An inverse association has been reported between EL and cognitive dysfunction in patients with senile dementia of Alzheimer type but it is yet unsettled whether education has a similar effect on cognition in PD. METHODS: Seventy-two PD patients (45 males, mean age 68.7+/-11.6 y) underwent a detailed neurologic examination, a battery of neuropsychologic tests, and questionnaires for the evaluation of psychosis, sleep disturbances, and depression. According to the number of educational years, patients were divided into 3 groups: low EL (0 to 8 y), (15 patients), intermediate EL (9 to 12 y) (28 patients), and high EL (>/=13 y) (29 patients). RESULTS: Patients with a higher EL had a better cognitive function and an association was found between the patients' EL and their scores in various neuropsychologic tests mainly those sensitive to frontal lobe dysfunction. Low education was associated with an increased risk for hallucinations and a trend for more depression, delusions, and sleep disturbances. CONCLUSIONS: The association between high educational attainment and the lower risk of cognitive dysfunction suggest that education might modulate cognitive performance in PD.  相似文献   
4.
BACKGROUND: The use of suctioned fat grafts for correction of soft tissue defects is a widespread procedure in esthetic and reconstructive surgery. The main disadvantage of this simple and sensible procedure is the unpredictable absorption rate of the fat graft. A lot of research has been performed aiming for enhancement of the take of the fat grafts. OBJECTIVE: Our study was performed to find if there is any favorable donor site for fat harvesting. METHODS: This in vivo experiment using the nude mice model enables the study of the long-term survival of human fat in an animal model. The fat was harvested from three donor areas: the thigh, abdomen, and breast of a 48-year-old woman who came for an elective esthetic procedure. After centrifugation, 1 cc of fat was injected subcutaneously into the scalp of the nude mouse. There were 15 mice in each of the three groups, according to the selected donor sites. The animals were sacrificed 16 weeks after the procedure. The extracted fat was evaluated in terms of weight, volume, and six histologic parameters: integrity, vascularization, cyst formation, fibrosis, necrosis, and inflammation. RESULTS: This study could not find any statistically significant differences between the three investigated donor sites in the evaluated parameters. CONCLUSION: On the basis of this study, there is no favorable area for harvesting fat grafts. The donor site can be chosen according to the preference of the surgeon and the patient.  相似文献   
5.
6.
7.
8.
9.
Inversion recovery (IR), commonly considered a pulse sequence capable of producing T1-weighted images with excellent display of normal anatomy, is versatile: The null point and peak time provide a useful, succinct summary of the properties of IR and its capacity for producing both T1- and T2-weighted images. Shortening of the inversion time (TI) and creation of a short-TI inversion-recovery (STIR) pulse sequence increases sensitivity to malignancy and other abnormalities by making the effects of prolonged T1 and T2 on signal intensity additive and by nulling the signal from fat. The authors examined over 300 patients with various malignancies and compared STIR images with T1- and T2-weighted images obtained at 0.5 T. In 43 cases, signal-difference-to-noise ratios (SD/Ns) were calculated between tumor, fat, and muscle. In general, STIR images demonstrated tumor as a conspicuously high-intensity area in a background of muted, discernible anatomic detail. The good contrast achieved with STIR sequences between tumor and fat (SD/N = 18.1) and tumor and muscle (SD/N = 12.9) consolidated into a single image the information contained separately on T1- and T2-weighted images, which facilitates efficient detection and localization of malignancy.  相似文献   
10.
Fine needle aspiration biopsy was performed in two case of infiltrating skull lesions. The role played by this relatively simple procedure in avoiding a major operation is discussed.  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