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   9552篇
  免费   460篇
  国内免费   60篇
耳鼻咽喉   69篇
儿科学   293篇
妇产科学   83篇
基础医学   1148篇
口腔科学   189篇
临床医学   577篇
内科学   2710篇
皮肤病学   118篇
神经病学   607篇
特种医学   405篇
外科学   1751篇
综合类   25篇
一般理论   1篇
预防医学   211篇
眼科学   144篇
药学   620篇
中国医学   10篇
肿瘤学   1111篇
  2023年   70篇
  2022年   141篇
  2021年   211篇
  2020年   121篇
  2019年   148篇
  2018年   204篇
  2017年   179篇
  2016年   193篇
  2015年   230篇
  2014年   253篇
  2013年   342篇
  2012年   529篇
  2011年   636篇
  2010年   357篇
  2009年   324篇
  2008年   567篇
  2007年   605篇
  2006年   593篇
  2005年   569篇
  2004年   591篇
  2003年   598篇
  2002年   532篇
  2001年   171篇
  2000年   143篇
  1999年   190篇
  1998年   123篇
  1997年   114篇
  1996年   81篇
  1995年   79篇
  1994年   62篇
  1993年   68篇
  1992年   109篇
  1991年   78篇
  1990年   86篇
  1989年   80篇
  1988年   68篇
  1987年   62篇
  1986年   56篇
  1985年   66篇
  1984年   38篇
  1983年   40篇
  1982年   28篇
  1981年   27篇
  1978年   35篇
  1974年   30篇
  1972年   19篇
  1971年   19篇
  1970年   19篇
  1969年   19篇
  1967年   20篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
When the concept of brain death is not widely accepted, the viability of renal allografts of non–heart–beating cadaveric donors is one of the serious concerns for transplant surgeons. At our center, 200 kidneys were harvested from cardiac arrest donors using the regional in situ cooling technique, and they were transplanted into recipients treated with cyclosporine (CS). The ages of donors ranged from 7 months to 67 years. At the bedside a specially designed double balloon catheter, 14F, was inserted into the aorta through the femoral artery just before or immediately after the cardiac arrest. A venous drainage tube was also placed in the vena cava. Following the cardiac arrest, both balloons of the aortic catheter were inflated, and regional in situ cooling with cold Lactate Ringer's solution started using the infusion pump at 20mL/kg/min. In the OR, both kidneys were removed en bloc and preserved in Collins'type solution. They were then transplanted into 200 patients treated with CS and steroid. After the transplant operations, 33 patients (16.5%) had immediate renal function, but 14 grafts (7.0%) were not successful and the patients have never had renal function. When several factors such as donor age, warm ischemic time (WIT; 12.3 ± 14.1 minutes), in situ cooling time (IST; 78.1 ± 18.0 minutes) and total ischemic time (TIT; 619 ± 340 minutes) were associated with the post–transplant renal function, only the donor age had significant correlation both with the posttransplant dialysis period and lowest serum creatine level, as follows: 10.5 days (≤ 40 years) vs. 14.6 days (>40 years); P < 0.05, and 1.16mg/dL (≤ 30 years) vs. 1.83 mg/dL (> 50 years) P < 0.001, respectively. Our findings indicate; 1) Due to the in situ cooling technique, the renal grafts of non–heart–beating cadavers can be expected to have relatively good function in the CS–treated recipients; 2) donor age is instrumental in predicting post–transplant renal function as well as the duration of ATN; 3) WIT, 1ST and TIT have no association with the post–transplant renal function if the duration of renal ischemia is within the acceptable range.  相似文献   
992.
The present study was designed to evaluate the technical feasibility and oncologic results of performing handsewn coloanal anastomosis (CAA). A total of 46 patients treated for lower rectal cancer using CAA were retrospectively studied, and the oncologic results were compared with those of 105 patients treated with abdominoperineal resection (APR). CAA was performed in patients who had both good mobility of the tumor and a distal clearance margin of more than 1.0 cm. No significant difference was noted in the mortality rates following the two operations (CAA 2.2% vs APR 1.9%). Pelvic recurrence was detected in two patients (4.5%) after CAA and in six patients (7.2%) after APR. The 5-year survival rate after CAA was 79.2% and that after APR was 72.6%. No significant difference was noted in the incidence of pelvic recurrence or the survival rates between the two operations. These results show that CAA could be an excellent reconstructive option in the treatment of lower rectal carcinoma for selected patients.  相似文献   
993.
Three cases of an extremely rare anomaly of the carotid artery are described herein. In these patients, the common carotid arteries, without bifurcation in the cervical portion, supplied multiple arterial branches, which are more commonly branches of the external carotid artery. The non-bifurcating carotid artery continued into the cranium as a normal internal carotid artery. This anomaly can be attributed to a maldevelopment of the vascular network during embryogenesis.  相似文献   
994.
Antibody-dependent cellular cytotoxicity (ADCC) and natural killer (NK) ativity were examined using MT-2 cells persistently infected by HTLV-1 as target cells, and mononuclear cells as effector cells, from helathy one-week-old newborn babies, infants, children and adults. More than 10% of ADCC was observed in 17 newborn babies out of 22 (77.3%) and in all 67 healthy one-month-old babies to adults, by adding serum from anti-HTLV-1 positive carriers. When anti-HTLV-1 negative serum was added, less than 10% of ADCC was observed. If infants without anti-HTLV-1 antibodies were breast-fed they had the possibility of HTLV-1 vertical transmission. There was no significant decrease in NK activity between 90 healthy newborn babies, infants, children, or adults. These results suggest that ADCC and NK activity protect against the transmission of HTLV-1 from mother to child.  相似文献   
995.
Background :
Urinary incontinence is one of the most common complications occurring after radical prostatectomy. We evaluated the efficacy of clenbuterol, a selective β2-adrenoceptor agonist, in the treatment of incontinence occurring after radical prostatectomy, using urodynamic assessment.
Methods :
Fourteen men (mean age, 68 years) with post-radical-prostatectomy incontinence were treated with 20 mg of clenbuterol twice a day for 1 month. The urodynamic assessment was performed on all patients before and after the administration of clenbuterol. A pad scoring system was used to gauge the severity of incontinence before and after treatment.
Results :
At 1 month after administration of clenbuterol, 9 of the 14 patients (64%) had dramatic improvement in pad scores. Treatment failed in 5 patients (36%) with severe incontinence. The results of urodynamic studies showed that the mean functional urethral length of the patients with post-radical-prostatectomy incontinence increased significantly after treatment.
Conclusion :
These results suggest that clenbuterol can be used as an effective agent for treating mild-to-moderate stress incontinence after radical prostatectomy.  相似文献   
996.
997.
Dimethyl sulfoxide (DMSO) exerts a number of biological effects including the promotion of cell differentiation in cultured cells. In this study, we examined the effect of DMSO on the adhesion of tumor cells to endothelial cells. In vitro treatment of human gastric adenocarcinoma (NUGC4) cells with DMSO resulted in increased adhesion to interleukin-1 (IL-l)-activated human endothelial cells compared with DMSO-untreated NUGC4 cells. In flow cytometry, treating NUGC4 cells with DMSO enhanced the expression of sialyl Lewis x (sialyl Lex) and sialyl dimeric Lex antigens on their surface. Also, the binding of Limulus polyphemus agglutinin (LPA), which specifically binds to cell-surface sialic acids, was increased by DMSO. The adhesion of DMSO-treated NUGC4 cells to activated endothelial cells was blocked by neuraminidase pre-treatment of tumor cells or by antibody against either endothelial leukocyte adhesion molecule-1 (ELAM-I) or sialyl Lex. Thus, it is suggested that enhanced adhesion following DMSO treatment is mediated by the interaction of sialyl Lex expressed on NUGC4 cells with ELAM-I of endothelial cells. The modulation of sialyl Lex antigen by DMSO provides a useful system for studying the regulatory mechanism of Lewis-related carbohydrate antigens and also for understanding the metastatic properties of cancer cells.  相似文献   
998.
We report an unusual case of dysembryoplastic neuroepithelial tumour (DNT) located in the occipital lobe presenting with only headache. A 31 year old woman presented with headache. She had no history of epilepsy and neurological examination revealed no abnormal findings. Computed tomography (CT) scanning revealed a multilobulated mass lesion with calcification in the right occipital lobe. Magnetic resonance (MR) imaging demonstrated a heterogeneously enhanced mass with hypointense signals on T1- and hyperintense signals on T2-weighted images. The lesion was totally resected and histopathologically diagnosed as DNT. Physicians must bear in mind that DNT may occur in the occipital lobe and present with only mass effect.  相似文献   
999.
Two hundred patients with prostatic cancer were enrolled in our previous study between 1984 and 1987. In this study, 96 patients of them were observed for 1 year or more after oral administration of Estracyt (estramustine sodium phosphate). Of these 96 cases, 33 patients were treated with Estracyt as primary treatment and 63 patient had been treated with other treatments before Estracyt treatment. Twelve patients were treated only with Estracyt and 84 patients also received other treatments. Thirty-eight patients were on primary therapy, 37 patients were on maintenance therapy, and 11 patients were on primary therapy, 37 patients were on maintenance therapy, and 11 patients were on the re-activated stage therapy and 10 patients were others. In conclusion, among the 67 cases in which the due judgement of the effect was possible, Estracyt was markedly effective in 10 cases (14.9%), effective in 16 cases (23.9%), slightly effective in 15 cases (22.4%) and ineffective in 26 cases (38.8%). The survival rate was 92.6% at the first year, 66.0% at the third year and 46.3% at the fifth year in the follow-up study. Adverse reactions were observed in 22 cases (22.9%), among which the administration was discontinued in 3 cases.  相似文献   
1000.
The controversy exists about the biological activity of carboxyl (C)-terminal parathyroid hormone (PTH) fragments. The present study was performed to examine the effect of C-terminal PTH fragments on osteoclast-like cell formation and bone-resorbing activity. Human (h) PTH-(1-84) caused a stimulation of osteoclast-like cell formation in osteoblast-containing mouse bone cell cultures more effectively than hPTH-(1-34). All of the C-terminal fragments examined [hPTH-(35-84), hPTH-(53-84) and hPTH-(69-84)] significantly stimulated osteoclast-like cell formation. The conditioned medium from osteoblastic UMR-106 cells pretreated with C-terminal PTH as well as amino-terminal PTH significantly stimulated osteoclast-like cell formation from mouse hemopoietic blast cells supported by granulocyte-macrophage colony stimulating factor. Moreover, all of the C-terminal fragments also caused a stimulation of osteoclast-like cell formation from hemopoietic blast cells even in the absence of osteoblasts. As for bone-resorbing activity of mature osteoclasts, all of the C-terminal fragments stimulated bone-resorbing activity in osteoblast-containing mouse bone cell cultures, while these fragments did not affect bone-resorbing activity of isolated rabbit osteoclasts. The present study indicates that C-terminal PTH fragments stimulate osteoclast-like cell formation as well as bone-resorbing activity of mature osteoclasts in the presence of osteoblast and also accelerate osteoclast-like cell formation from hemopoietic blast cells in the absence of osteoblasts.  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