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   876篇
  免费   24篇
  国内免费   4篇
耳鼻咽喉   23篇
儿科学   29篇
妇产科学   73篇
基础医学   70篇
口腔科学   33篇
临床医学   86篇
内科学   149篇
皮肤病学   6篇
神经病学   47篇
特种医学   22篇
外科学   253篇
综合类   14篇
一般理论   2篇
预防医学   11篇
眼科学   27篇
药学   18篇
中国医学   3篇
肿瘤学   38篇
  2023年   6篇
  2022年   5篇
  2021年   17篇
  2020年   8篇
  2019年   12篇
  2018年   19篇
  2017年   14篇
  2016年   26篇
  2015年   42篇
  2014年   34篇
  2013年   67篇
  2012年   69篇
  2011年   62篇
  2010年   49篇
  2009年   42篇
  2008年   51篇
  2007年   53篇
  2006年   59篇
  2005年   77篇
  2004年   65篇
  2003年   36篇
  2002年   39篇
  2001年   9篇
  2000年   6篇
  1999年   7篇
  1998年   2篇
  1997年   2篇
  1995年   3篇
  1994年   2篇
  1993年   1篇
  1992年   4篇
  1991年   3篇
  1990年   1篇
  1989年   1篇
  1988年   3篇
  1987年   2篇
  1984年   1篇
  1978年   1篇
  1971年   1篇
  1969年   2篇
  1966年   1篇
排序方式: 共有904条查询结果,搜索用时 15 毫秒
1.
2.
BACKGROUND: Thrombotic thrombocytopenic purpura (TTP) is a multisystem disorder characterised by platelet aggregation causing microvascular occlusion. Early diagnosis and utilization of plasmapheresis can provide an improvement in prognosis. CASE REPORT: A 17 year old male with classical findings of TTP was later diagnosed as systemic lupus erythematosus (SLE). Plasmapheresis resulted in the significant amelioration of the course. CONCLUSION: The coexistence of TTP and SLE may facilitate a better understanding of in the pathophysiology of TTP. These association may provide the role of autoimmunity in TTP. SLE should be considered in the differential diagnosis of patients with TTP because of therapeutic implications.  相似文献   
3.
4.
Laparoscopy or laparotomy for the management of endometrial cancer.   总被引:2,自引:0,他引:2  
OBJECTIVE: The aim of this study was to evaluate the feasibility of laparoscopy in the management of early stage endometrial cancer. METHODS: Fifty-two patients with endometrial cancer who underwent surgical staging consisting of total hysterectomy, bilateral salpingo-oophorectomy with pelvic lymph node dissection, and cytology between 1998 to 2002 were included in the study. Laparotomy and laparoscopy were randomly offered to patients upon admittance. RESULTS: Of 52 patients, 26 underwent laparotomy and the remaining 26 underwent laparoscopic staging surgery. No significant difference existed between the demographic characteristics of the 2 groups. The mean number of harvested lymph nodes was 18.2 in the laparoscopic group and 21.1 in the laparotomic group (P>0.05). Pelvic lymph node metastases were detected in 7.7% of the patients in the laparoscopy group and 15.4% in the laparotomy group, and the difference was not significant. Adjuvant radiotherapy was applied later to 42.3% of the laparoscopy group and 38.5% of the laparotomy group. Operative morbidity was higher in the laparotomy group mainly because of postoperative wound infection, and the patients in the laparotomy group had a longer hospital stay. CONCLUSION: Laparoscopic surgery is a method that can be applied as well as laparotomy in the management of endometrial cancer. Lymph node number and detection of lymph node metastasis did not differ significantly in laparotomic and laparoscopic approaches. Wound infections were more frequent in laparotomies.  相似文献   
5.
A series of clones displaying high frequency switching phenotypes for expression of the adenine phosphoribosyltransferase (aprt) gene were previously isolated from the P19 mouse embryonal carcinoma stem cell line. Most clones contained only oneaprt allele. We report here the characterization of each of these clones with regards to enzymatic activity, mRNA steady state levels, DNA methylation, and chromatin conformation. When clones were selected for resistance to the purine analog 2,6-diaminopurine, which requires markedly reduced levels of APRT enzymatic activity, two distinct classes were observed. The first class was associated with reduced or undetectable levels ofaprt mRNA, hypermethylation of the 5 CpG island, and a closed chromatin conformation within this region. When clones of this class were selected for reacquisition of APRT enzymatic activity they were found to have increased mRNA levels, a hypomethylated CpG island, and an open chromatin conformation. In contrast, the second class of clones displayed wild-type levels of mRNA, CpG island hypomethylation, and an open chromatin conformation regardless of whether they were selected for the presence or absence of APRT enzymatic activity. The implications of these results for general mechanisms of epigenetic change in somatic cells and the possibility that expression of the mouseaprt gene may be developmentally regulated are discussed.  相似文献   
6.
Atalay E  Karaali K  Akar M  Ari ES  Simsek M  Atalay S  Zorlu G 《Maturitas》2005,50(4):282-288
Objective: To determine the effects of hormone replacement therapy (HRT) on ocular blood flow.

Study design: In a prospective controlled study, 40 healthy women who presented to the menopause clinic between December 2000 and December 2001 were randomly assigned into the study. The HRT-receiving group was administered estradiol 17-valerate 2 mg the first 11 days, and estradiol 17-valerate 2 mg plus ciproterone acetate 1 mg the next 10 days of the monthly cycle for 6 months. The control group did not receive any HRT for 6 months. The ocular colour Doppler analysis were performed at baseline and after 3 and 6 months. The ocular Doppler analysis was performed in the first half of the cycle in the HRT-receiving group.

Results: Central retinal artery and ophthalmic artery basal Doppler index (peak systolic velocity, end-diastolic velocity, resistive index and pulsatility index) values of the two groups at the beginning of the study did not show any statistically significant difference. Both the right and the left central retinal artery pulsatility index (PI) values of the study group, who received HRT at the end of the third and sixth months, showed a statistically significant decline (paired-samples test, P < 0.05), while the decrease in the resistive indexes was not significant.

Conclusion: These results suggest that 6 months of combined hormone replacement therapy with estradiol 17-valerate 2 mg plus ciproterone acetate 1 mg improves ocular vascular Doppler indices which may be a reflection of cerebral vascular status.  相似文献   

7.
Tacrolimus-associated mutism after orthotopic liver transplantation   总被引:8,自引:0,他引:8  
BACKGROUND: Mutism/speech apraxia has been well documented as a toxic effect of cyclosporine after liver transplantation but has been reported only rarely with tacrolimus. Brain imaging with magnetic resonance or computed tomography has failed to demonstrate abnormalities in affected patients. METHODS: We present the first example of an acute onset of loss of speech associated with a sudden elevation of serum tacrolimus level after successful orthotopic liver transplantation. We also describe the positron emission tomography (PET) scan of this patient's brain. RESULTS: PET scan imaging of the brain was abnormal, demonstrating decreased metabolism in the posterior temporo-parieto-occipital regions. Statistical probability mapping revealed additional areas of hypometabolism in the cingulate gyrus. CONCLUSIONS: PET scan revealed abnormalities of the brain in a patient with tacrolimus-induced mutism. The cingulate gyrus may play a role in the mutism/speech apraxia syndrome seen with cyclosporine/tacrolimus neurotoxicity.  相似文献   
8.
9.
Cornual (interstitial) pregnancy, a very rare form of ectopic pregnancy, accounts for 2–4% of all tubal pregnancies in which conception is located in the proximal interstitial portion of the fallopian tube. Cornual resection by laparotomy is generally the preferred method of treatment, although more conservative approaches have also been described. We report a case of cornual pregnancy that was successfully treated with a single dose of 100 mg methotrexate injected into the mass of the ectopic cornual pregnancy. The serum human chorionic gonadotropin (hCG) level decreased to undetectable levels on the 60th post-operative day.  相似文献   
10.
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