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   591篇
  免费   25篇
  国内免费   7篇
耳鼻咽喉   21篇
儿科学   35篇
妇产科学   27篇
基础医学   31篇
口腔科学   23篇
临床医学   37篇
内科学   120篇
皮肤病学   3篇
神经病学   23篇
特种医学   30篇
外科学   153篇
综合类   11篇
预防医学   20篇
眼科学   19篇
药学   41篇
肿瘤学   29篇
  2022年   6篇
  2021年   14篇
  2020年   6篇
  2019年   15篇
  2018年   14篇
  2017年   12篇
  2016年   18篇
  2015年   13篇
  2014年   21篇
  2013年   39篇
  2012年   50篇
  2011年   45篇
  2010年   21篇
  2009年   15篇
  2008年   41篇
  2007年   48篇
  2006年   52篇
  2005年   51篇
  2004年   32篇
  2003年   35篇
  2002年   26篇
  2001年   12篇
  2000年   5篇
  1999年   8篇
  1998年   4篇
  1997年   4篇
  1996年   2篇
  1994年   3篇
  1993年   2篇
  1992年   4篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1974年   1篇
排序方式: 共有623条查询结果,搜索用时 15 毫秒
71.
We report a 7-year-old child with Laurence-Moon-Biedl syndrome, an autosomal recessive syndrome, with impaired renal function detected by means of technetium-99m diethylenetriamine-pentaacetic acid (Tc-99m DTPA), technetium-99m dimercaptosuccinic acid (Tc-99m DMSA) scintigraphy, and ultrasonography. The altered renal morphology and decreased renal functions are documented.  相似文献   
72.
In this study, twelve new hexahydropyrimidine-2,4-dione derivatives were synthesized and screened for their anticonvulsant activities. All the compounds (7a-1) which have 6-arylhexahydropyrimidine-2,4-dione and N,N-disubstituted dithiocarbamate structures were prepared by the reaction with appropriate 3-(2-chloroethyl)-6-arylhexahydropyrimidine-2,4diones and the corresponding N,N-disubstituted dithiocarbamate potassium salts. The structure of the synthesized compounds was confirmed by UV, IR, 1H-NMR and elemental analysis. Their anticonvulsant activities were determined by maximal electroshock (MES), subcutaneous pentetrazol (metrazol, scMet) and rotorod toxicity tests for neurological deficits. According to the activity studies, 6-(4-chlorophenyl)hexahydropyrimidine-2,4-dione derivatives (7e-h) were found to be highly protective against MES and scMet. Neurotoxicity was not observed in any of the tested compounds.  相似文献   
73.
BACKGROUND AND AIM OF THE STUDY: Fibroblast growth factor-2 (FGF-2) is a multifunctional protein which plays a role in smooth muscle cell growth, wound healing, tissue repair and angiogenesis. FGF-2 is also released by mechanically wounded cells. Herein, the importance of FGF-2 release from periannular tissue in the mechanism of pannus formation in obstructed mechanical prostheses was investigated. METHODS: Between January 1993 and December 2002, 35 patients with an obstructed bileaflet prosthetic mitral valve were classified according to the nature of obstruction as either thrombus or pannus. Data were related to patient age and gender, prosthesis model and size, intraoperative and pathology findings, and interval between implant and thrombosis. FGF-2 release was monitored immunohistochemically in all cases. RESULTS: Thrombus formation was found in 19 patients, and pannus formation in 16. Patients were reoperated on after 3.10 +/- 0.7 years in the thrombus group, and after 6.3 +/- 0.46 years in the pannus group (p = 0.04). A foreign body reaction was found 78.9% of thrombus patients and 81.2% of pannus patients (p = 0.602), chronic inflammation in 31.5% and 50%, respectively (p = 0.317), and FGF-2 release in 78.9% and 87.5%, respectively (p = 0.582). CONCLUSION: As FGF-2 release was similar in both patient groups, the duration of FGF-2 release from injured periannnular tissue was considered to form part of the chronic healing process, and was not attributed to mitral valve obstruction by pannus formation.  相似文献   
74.
75.
76.

Objectives

To evaluate the incidence of breast lesions with a histopathological diagnosis of focal fibrosis based on imaging guided core biopsy, to review the radiologic findings and to assess the diagnostic reliability of 14 G core needle biopsy.

Materials and methods

723 patients, who had undergone 14 G core biopsy and/or surgical excisions, were retrospectively analyzed. Overall, 43 lesions were diagnosed as focal fibrosis. Physical examination, mammography, ultrasonography, and follow-up findings were all reviewed.

Results

Radiological evaluation revealed that 35 (81%) lesions were solid masses. Of 35 mass lesions, 24 (69%) were well circumscribed, the remaining 11 (31%) lesions were ill defined on mammograms or sonograms. None of the lesions had pathological microcalcifications. Three lesions were surgically excised because of radio-pathological discordance after core needle biopsy.

Conclusions

Focal fibrosis of the breast is a benign condition and reflects the ductal and lobular atrophy secondary to stromal proliferation. The radiological findings of this entity may vary and sometimes mimic those of malignant lesions. The incidence of focal fibrosis among our study population is 6% and a well-defined mass lesion is the most frequent finding. Core needle biopsy is a safe and reliable diagnostic procedure in the management of these cases.  相似文献   
77.
78.
BACKGROUND: It is unclear how well self-reports and clinician ratings of performance in the instrumental activities of daily living (IADLs; household maintenance tasks) correspond and why they may differ. METHODS: We assessed clinician-rated IADL performance using an occupational therapy protocol, the Assessment of Motor and Process Skills (AMPS). AMPS and self-rated IADL disability were compared in two groups of nondemented elderly persons without ADL limitation: a group with functional limitation only (self-reported difficulty in some area of upper or lower body function, n = 139) and a group that reported functional limitation plus IADL disability (difficulty in at least one IADL task, n = 49). Occupational therapists were blind to self-reports, and all assessments were conducted in respondent homes. RESULTS: Self-rated IADL disability was significantly associated with the AMPS motor skill score (r = -.34, p <.001), but the motor skill score was only moderately sensitive (61%) and specific (67%) in identifying self-rated disability. In adjusted logistic regression models, clinician-rated performance and self-rated IADL disability shared some physical predictors, but only clinician-rated performance was related to cognitive status. AMPS process skill scores did not relate to self-rated IADL disability or physical or cognitive status. CONCLUSIONS: In this sample of older adults without dementia or ADL disability, clinician ratings of IADL motor skill and self-rated IADL disability were correlated. Physical deficits appear to be more salient in self-ratings than is cognitive ability, because cognitive ability (in particular, verbal fluency) was associated only with clinician-rated IADL performance.  相似文献   
79.
80.
The acute effects of extracorporeal shock waves on lung morphology were studied by light microscopy in 30 New Zealand rabbits. The left kidneys of the ten animals were exposed to 2,000 shockwaves at 18 kV under anesthesia (ESWL group). Ten rabbits were in the control group; an intramuscular anesthetic agent (ketamine) and intravenous contrast media were administered to ten animals in the sham group. Localization of the left kidneys was achieved following contrast medium injection through an ear vein under fluoroscopic control. The animals were killed after the ESWL procedures and the lungs were removed. Edema, emphysema, hemorrhage, congestion, inflammation, loss of normal structure, and epithelial desquamation were determined and graded between 0 and 3 in all areas of both lungs. In order to determine whether proximity has any effect on the histopathological changes, left and right lungs were evaluated separately as well as upper and lower lobes. We found that ESWL exposed to kidney also affects all areas of the lungs in a rabbit model.  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