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   1454篇
  免费   104篇
  国内免费   2篇
耳鼻咽喉   17篇
儿科学   75篇
妇产科学   96篇
基础医学   191篇
口腔科学   84篇
临床医学   147篇
内科学   351篇
皮肤病学   26篇
神经病学   84篇
特种医学   34篇
外科学   239篇
综合类   17篇
一般理论   1篇
预防医学   46篇
眼科学   26篇
药学   57篇
中国医学   1篇
肿瘤学   68篇
  2023年   17篇
  2022年   29篇
  2021年   55篇
  2020年   38篇
  2019年   57篇
  2018年   51篇
  2017年   42篇
  2016年   67篇
  2015年   67篇
  2014年   69篇
  2013年   83篇
  2012年   105篇
  2011年   74篇
  2010年   43篇
  2009年   54篇
  2008年   75篇
  2007年   103篇
  2006年   94篇
  2005年   88篇
  2004年   61篇
  2003年   46篇
  2002年   33篇
  2001年   24篇
  2000年   10篇
  1999年   23篇
  1998年   11篇
  1997年   3篇
  1996年   5篇
  1994年   4篇
  1993年   3篇
  1992年   12篇
  1991年   13篇
  1990年   13篇
  1989年   11篇
  1988年   3篇
  1987年   7篇
  1986年   4篇
  1985年   3篇
  1984年   7篇
  1983年   3篇
  1980年   3篇
  1978年   4篇
  1975年   2篇
  1974年   3篇
  1973年   7篇
  1972年   3篇
  1971年   6篇
  1970年   4篇
  1969年   3篇
  1968年   2篇
排序方式: 共有1560条查询结果,搜索用时 15 毫秒
31.
Neurological Sciences - Alzheimer’s disease (AD) can be either sporadic or familial, and familial forms of AD accounts for only 5% of the cases. So far, autosomal dominantly inherited...  相似文献   
32.
The use of immediate on-site evaluation of fine-needle aspiration biopsy (FNAB) specimens can determine the adequacy of specimens and provides a specific preliminary diagnosis. In this prospective study, we evaluated the impact of on-site assessment of thyroid FNAB performed under ultrasound guidance. Totally, 204 (170 female, 34 male) patients (102 on site, 102 control group) were included. The patients were randomized on site and regular cytologic examination groups. Quick May-Grünwald Giemsa stain was used for on-site examination and FNA was continued until adequate aspirate for optimal cytological examination. Two (2.0 %) of the 102 patients evaluated with on-site examination had a nondiagnostic result. However, 16 (15.7 %) of the 102 patients examined by regular cytologic examination method, had nondiagnostic result. The difference between these two groups was statistically significant (p?<?0.0001). The major cause of a nondiagnostic thyroid FNAB specimen is the failure to aspirate a sufficient number of cells necessary for diagnosis cystic lesions. Immediate on-site evaluation can significantly decrease the nondiagnostic rate of thyroid FNAB specimens.  相似文献   
33.
Objective:To determine the total oxidant status (TOS), total antioxidant status (TAS), and the 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels and their interrelationship in the saliva of children undergoing fixed orthodontic therapy.Materials and Methods:Thirty children were randomly divided into three groups. The attachments were bonded to all of the teeth using three different orthodontic composites: Transbond XT, Kurasper F, and GrenGloo. The salivary levels of TOS, TAS, and 8-OHdG were determined three times, as follows: before treatment (T1) and at 1 month (T2) and 3 months (T3) following appliance placement. All data were statistically analyzed.Results:There were no significant differences in TOS, TAS, and 8-OHdG within the same time periods among the three different orthodontic composites (P > .05). TAS in all composite groups decreased over time. These decreases were found to be significant for Kurasper F and GrenGloo at the T1–T3 and T2–T3 time periods (P < .05). In all composite groups 8-OHdG decreased between T1 and T2 (P < .05). However, 8-OHdG in all composite groups increased from T2 to T3. These differences in 8-OHdG were significant in Kurasper F and GrenGloo (P < .05).Conclusions:Fixed orthodontic appliances bonded with the tested composites did not increase the cytotoxicity markers in saliva.  相似文献   
34.
35.

Purpose

We studied the use of magnetic resonance imaging in the diagnosis of penile fracture.

Materials and Methods

Between 1997 and 2012, fifteen patients (age range 17-48 years, mean age 37 years) with suspected penile fracture underwent MRI examinations. Ten patients were injured during sexual intercourse, whereas four patients were traumatized by non-physiological bending of the penis during self manupilation, one patient was traumatized falling from the bed. Investigations were performed with 1.5T MR unit. With the patient in the supine position, the penis was taped against the abdominal wall and surface coil was placed on the penis. All patients were studied with axial, coronal, sagittal precontrast and postcontrast T1-weighted TSE(TR/TE:538/13 msn) and T2-weighted TSE(5290/110 msn) sequences. All patient underwent surgical exploration. The follow-up ranged from 3 months to 72 months. Clinically all patients showed normal healing process without complications. In 11 patients a shortening and thickening of tunica albuginea was observed. Three patients have post traumatic erectil disfunction.

Results

In all patient corpus cavernosum fractures were clearly depicted on a discontinuity of the low signal intensity of tunica albuginea. These findings were most evident on T1WI and also depicted on T2W sequences. Images obtained shortly after contrast medium administration showed considerable enhancement only in rupture site. Subcutaneous extratunical haematoma in all patients were also recognizable on T2 WI. MRI findings were confirmed at surgery.

Conclusions

Magnetic resonance imaging is of great value for the diagnosis of penile fracture. Furthermore this method is well suited for visualising the post-operative healing process  相似文献   
36.
37.
Intra-abdominal hypertension and abdominal compartment syndrome (IAH/ACS) are life-threatening conditions and caused by several clinical status. Although there is insufficient data regarding its effects on adrenal glands. This study aimed to identify whether elevated intra-abdominal pressure (IAP) caused any alteration on the morphology and function of adrenal glands in a rat model. Twenty four Sprague-Dawley male rats were included in the study. Animals were allocated into 4 groups. IAP was elevated to 15 mmHg for one hour and four hours in group 2 and 4. Group 1 and 3 were sham groups. Blood samples were taken for the assessment of plasma adrenaline, noradrenaline, and corticosterone levels and adrenalectomies were performed to evaluate apoptosis. Blood adrenaline, noradrenaline and corticosterone levels were significantly higher in the study groups compared with the sham groups. However, there were no significant changes in apoptotic index scores in the study groups as compared to sham groups. These results support that increased IAH leads to discharge of catecholamine and corticosterone from the adrenal glands. Failure to demonstrate similar changes in apoptotic index score may be concluded as apoptosis is not a leading pathway for impairment of adrenal glands during IAH period.  相似文献   
38.
Acetaminophen (APAP) is the most commonly reported toxic ingestion in the world. Severe liver injury resulting from overdose or chronic use of APAP remains a significant clinical problem. In recent years, the mechanisms underlying liver injury caused by APAP have become much better understood. We have studied the protective effect of chitosan supplementation against APAP-induced hepatotoxicity with respect to changes in the levels of total and lipid-bound sialic acid in the serum and in the liver tissue and changes in the activity of diagnostic marker enzymes, lipid peroxidation, and ceruloplasmin oxidase enzyme in normal and experimental groups of rats. During the experimental period, chitosan (200 mg/kg body weight per day) was administered to APAP + chitosan-treated rats by oral gavage. Results showed that treatment with APAP induced a significant increase in the serum alanine aminotransferase and alkaline phosphatase activities, in total and lipid-bound sialic acids levels, and in the liver lipid peroxide content. The administration of chitosan significantly prevented APAP-induced alterations in the levels of diagnostic marker enzymes, total sialic acid, lipid-bound sialic acid, and malondialdehyde in the experimental groups of rats. Furthermore, chitosan administration increased the activity of ceruloplasmin oxidase. In conclusion, our results suggest that chitosan has a protective effect on APAP-induced hepatic injury in rats. The study sheds light on the therapeutic potential of chitosan in an APAP-induced hepatotoxicity model.  相似文献   
39.

Background  

Hepatic stellate cells (HSC) play a major role in the progression of liver fibrosis.  相似文献   
40.
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