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   1822篇
  免费   111篇
  国内免费   12篇
耳鼻咽喉   1篇
儿科学   45篇
妇产科学   46篇
基础医学   230篇
口腔科学   55篇
临床医学   157篇
内科学   545篇
皮肤病学   61篇
神经病学   147篇
特种医学   30篇
外科学   165篇
综合类   5篇
一般理论   3篇
预防医学   205篇
眼科学   22篇
药学   96篇
中国医学   9篇
肿瘤学   123篇
  2023年   19篇
  2022年   29篇
  2021年   89篇
  2020年   46篇
  2019年   75篇
  2018年   71篇
  2017年   51篇
  2016年   36篇
  2015年   75篇
  2014年   70篇
  2013年   110篇
  2012年   165篇
  2011年   174篇
  2010年   93篇
  2009年   95篇
  2008年   139篇
  2007年   107篇
  2006年   111篇
  2005年   88篇
  2004年   87篇
  2003年   67篇
  2002年   60篇
  2001年   10篇
  2000年   9篇
  1999年   10篇
  1998年   14篇
  1997年   10篇
  1996年   8篇
  1995年   8篇
  1994年   6篇
  1993年   3篇
  1992年   3篇
  1991年   1篇
  1990年   1篇
  1989年   2篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
排序方式: 共有1945条查询结果,搜索用时 31 毫秒
81.
Reviews of the efficacy of acupuncture as a treatment for acute low back pain have concluded that there is insufficient evidence for its efficacy and that more research is needed to evaluate it. A multicentre randomized controlled trial was conducted at 4 primary-care centres in Spain to evaluate the effects of acupuncture in patients with acute nonspecific low back pain in the context of primary care. A total of 275 patients with nonspecific acute low back pain (diagnosed by their general practitioner) were recruited and assigned randomly to 4 different groups: conventional treatment either alone or complemented by 5 sessions over a 2-week period of true acupuncture, sham acupuncture, or placebo acupuncture per patient. Patients were treated from February 2006 to January 2008. The primary outcome was the reduction in Roland Morris Disability Questionnaire scores of 35% or more after 2weeks' treatment. The patients in the 3 types of acupuncture groups were blinded to the treatments, but those who received conventional treatment alone were not. In the analysis adjusted for the total sample (true acupuncture relative risk 5.04, 95% confidence interval 2.24-11.32; sham acupuncture relative risk 5.02, 95% confidence interval 2.26-11.16; placebo acupuncture relative risk 2.57 95% confidence interval 1.21-5.46), as well as for the subsample of occupationally active patients, all 3 modalities of acupuncture were better than conventional treatment alone, but there was no difference among the 3 acupuncture modalities, which implies that true acupuncture is not better than sham or placebo acupuncture.  相似文献   
82.

Objective

To measure endometrial thickness and characterize ultrasonographic endometrial images induced by tamoxifen, as well as to determine changes in ultrasonographic patterns throughout treatment.

Patients and methods

We analyzed 278 patients with breast cancer between 1995 and 2000 under adjuvant therapy with tamoxifen for 5 years. Annual ultrasonographic examination was performed. Endometrial thickness and the morphological endometrial patterns in stored ultrasonographic images were retrospectively analyzed.

Results

Endometrial thickness significantly increased during treatment from a mean of 7.84 mm in the first year to 16.67 mm in the fifth year. Five endometrial patterns were found on ultrasonography in patients receiving tamoxifen: linear, heterogeneous-hyperechoic, homogeneoushyperechoic, endometrial polyp, and suspicious for malignancy. The homogeneous-hyperechoic pattern predominated in the first year and the heterogeneous-hyperechoic pattern in the fifth year.

Conclusions

Tamoxifen increases endometrial thickness in the course of treatment and induces five ultrasonographic patterns which change year-by-year.  相似文献   
83.
84.
To identify low-penetrance genes related to sporadic essential tremor (ET) at the CYP2Clocus, located in chromosome 10 q23.33. Leukocytary DNA from 200 ET patients and a control group of 300 unrelated healthy individuals with known CYP2C19 genotypes was studied for common CYP2C8 and CYP2C9 allelic variants by using amplification-restriction analyses. Patients with ET showed the following differences compared with healthy subjects: a 1.6-fold reduction in the frequency for CYP2C8*3 (p=0.006), a 1.35-fold reduction of CYP2C9*2 (p=0.05) and a 1.52-fold reduction in the frequency for CYP2C9*3 (p=0.07). The frequency for patients with ET carrying at least one defective allele was 1.33-fold reduced as compared with healthy subjects (p=0.002). In addition, a disruption of the CYP2C8*3/CYP2C9*2 linkage disequilibrium was observed in ET patients, with a 2.1-fold reduction in the percentage for carriers of the haplotype CYP2C8*3 plus CYP2C9*2 in ET patients (p=0.0001). These findings were independent of gender, age, age of onset, or clinical symptoms. These results suggest that alterations at the CYP2C gene locus are associated with the risk for ET.  相似文献   
85.
86.
87.
88.
89.
Effective long-term management of urolithiasis depends on identification and manipulation of factors contributing to initial stone formation; identification of these factors depends on accurate identification of the mineral composition of the urolith involved. The purpose of this study was to determine the chemical composition of uroliths obtained from the low urinary tract of dogs in Mexico City. One hundred and five cases of urolithiasis were studied in which stones were surgically obtained from the low urinary tracts of dogs treated in different hospitals. The chemical composition of the uroliths was quantitatively and qualitatively determined by stereoscopic microscopy, IR-spectroscopy, scanning electron microscopy and X-ray microanalysis. Age of animals ranged from 4 months to 14 years, with a median of 5 years. Composition and distribution of the uroliths were struvite 38.1%, calcium oxalate 26.7%, silica 13.3%, urate 7.6%, mixed 11.4%, compounds 1.9%, and cystine 1%. Most uroliths were found in pure breed dogs (75.2%); 23 different breeds were identified, and more than half of the submissions were from breeds of small size. In our study, the frequency of struvite, calcium oxalate, cystine, urates, mixed and compounds stones are in agreement with papers that report on dog populations in America and Europe, but a higher frequency of silica uroliths was observed in Mexico City dogs.  相似文献   
90.
Hemodialysis induces production of the hepatocyte growth factor (HGF) and decrease of serum hepatitis C virus (HCV) RNA in patients with HCV infection, but it is not known if the hemodialysis schedule or type of membrane affect both the HGF production and HCV viremia. The effects on both parameters of alternate‐day intermittent hemodialysis and short‐daily hemodialysis and high and low flux membranes were investigated in 41 patients treated by hemodialysis. Sixteen (39%) patients were anti‐HCV positive and 11 (69%) had HCV RNA. Twenty‐six patients were on alternate‐day intermittent and 15 on short‐daily hemodialysis. High flux membranes were used for 29 patients and low flux membranes for 12 patients. A decrease in HCV RNA was observed at the end of hemodialysis (8.6 × 105 ± 1.1 × 106 IU/ml vs. 4.4 × 105 ± 7.3 × 105 IU/ml, P = 0.003). The proportion of HCV RNA decrease was similar in patients dialyzed with both schedules and with both types of membranes. The HGF levels increased from 2,605.9 ± 1,428.7 to >8,000 pg/ml at 15 min. At the end of the session, the HGF levels decreased to 5,106.7 ± 2,533.9 pg/ml. The HGF levels at the start of the next session were similar to those at baseline (2,680.0 ± 1,209.3 pg/ml). The increase and dynamics of the HGF levels were similar in patient's hemodialyzed with both schedules and with both types of membranes. These results suggest that changes in HCV RNA and HGF levels during hemodialysis are not influenced by the schedule or type of membrane used. J. Med. Virol. 82: 763–767, 2010. © 2010 Wiley‐Liss, Inc.  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