全文获取类型
收费全文 | 251篇 |
免费 | 8篇 |
国内免费 | 68篇 |
专业分类
儿科学 | 6篇 |
妇产科学 | 6篇 |
基础医学 | 22篇 |
口腔科学 | 1篇 |
临床医学 | 59篇 |
内科学 | 57篇 |
皮肤病学 | 2篇 |
神经病学 | 7篇 |
特种医学 | 47篇 |
外科学 | 15篇 |
综合类 | 13篇 |
预防医学 | 25篇 |
眼科学 | 1篇 |
药学 | 52篇 |
肿瘤学 | 14篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 10篇 |
2012年 | 3篇 |
2011年 | 5篇 |
2010年 | 6篇 |
2009年 | 9篇 |
2008年 | 5篇 |
2007年 | 44篇 |
2006年 | 7篇 |
2005年 | 14篇 |
2004年 | 3篇 |
2003年 | 8篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 10篇 |
1998年 | 22篇 |
1997年 | 19篇 |
1996年 | 19篇 |
1995年 | 16篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 14篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有327条查询结果,搜索用时 10 毫秒
91.
WANG Guo Zhong RU Xin DING Li Hua LI He Qun 《World journal of gastroenterology : WJG》1998,4(2):169-170
ShorttermefectofSalviamiltiorhizaintreatingrataceticacidchronicgastriculcerandlongtermefectinpreventingrecurenceWANGGuoZho... 相似文献
92.
RS McLeod BG Wolff AH Steinhart PW Carryer K O'Rourke DF Andrews JE Blair JR Cangemi Z Cohen JB Cullen RG Chaytor GR Greenberg NM Jaffer KN Jeejeebhoy RL MacCarty RL Ready LH Weiland 《Gastroenterology》1997,113(6):1823-1827
BACKGROUND & AIMS: The aim of this study was to determine the risk of endoscopic/radiological recurrence of Crohn's disease postoperatively and the long-term outcome. METHODS: A randomized placebo-controlled trial was performed to determine the effectiveness of mesalamine in preventing recurrent Crohn's disease postoperatively. Patients in the control group were examined endoscopically/radiologically before entry into and annually during the trial. Findings were classified as minimal or severe. RESULTS: There were 76 patients (49 men and 37 women; mean age, 37.1 +/- 13.2 years). Fifty (61.7%) had terminal ileal resections. Overall, 55 endoscopic/radiological recurrences were observed in 51 patients (67.1%). Expressed actuarially, the recurrence rate was 27.5% at 1 year (95% confidence interval [CI], 15.8%-37.6%), 60.8% at 2 years (95% CI, 46%-71.3%), and 77.3% at 3 years (95% CI, 62.7%-86.3%). Nineteen (37%) were symptomatic and 12 (24%) were initially asymptomatic but later became symptomatic (mean, 13.0 +/- 8.8 months), whereas 20 (39%) remained asymptomatic (mean, 16.9 +/- 17.4 months). Patients with severe endoscopic/radiological disease were significantly more likely to be or become symptomatic than those with minimal disease (23 of 32 vs. 8 of 19, respectively; P = 0.0437). CONCLUSIONS: This study suggests that postoperative endoscopic/radiological recurrences occur later than previously reported. Furthermore, many of these patients, especially with minimal disease, will remain asymptomatic. (Gastroenterology 1997 Dec;113(6):1823-7) 相似文献
93.
Down syndrome (DS) children with acute myeloid leukemia (AML) have significantly higher event-free survival (EFS) rates compared with non- DS children when treated with protocols containing 1-beta-D- arabinofuranosylcytosine (ara-C). Sensitivity and metabolism of ara-C was examined in myeloblasts from DS and non-DS patients with AML, DS infants with the transient myeloproliferative disorder, and Epstein- Barr Virus (EBV) transformed lymphoblastoid cell lines with and without trisomy 21. DS myeloblasts were approximately 10-fold more sensitive to ara-C (measured by the 3-[4,5-dimethyl-thiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) colorimetric sensitivity assay), compared with non-DS myeloblasts, following exposure to ara-C for 72 hours. Mean levels of l-beta-D-arabinofuranosylcytosine 5'-triphosphate (ara-CTP) were significantly higher in DS myeloblasts compared with non-DS myeloblasts after incubation with 5 micromol/L ara-C (621.4 v 228.4 pmol/mg protein). DS cell lines also generated higher levels of ara-CTP compared with cell lines with diploid chromosome numbers (66.5 v 13.6 pmol/mg protein and 137.6 v 41.7 pmol/mg protein at 1 and 5 micromol/L ara-C, respectively). Elevated ara-CTP levels in the DS cells were accompanied by slightly lower levels of endogenous deoxycytidine triphosphate (dCTP) pools, slightly greater extent of ara-C incorporation into DNA, and increased relative numbers of double strand DNA strand breaks. There were no significant differences in the cell cycle distributions of DS and non-DS cells. These in vitro studies support our hypothesis that enhanced metabolism of ara-C in DS cells may be a contributing factor to the superior survival rate of DS children with AML and is possibly based on a gene dosage effect of genes localized to chromosome 21 including cystathionine-beta-synthase. Further study of the mechanisms (ie, alterations in dCTP pools and DNA methylation) involved may lead to improvements in the treatment of all AML patients. 相似文献
94.
95.
96.
Recent advances in diagnosis and treatment of venous thromboembolism have been associated with increasing use of low molecular weight heparins (LMWH) for treatment and prophylaxis of this disease. Despite this trend for more widespread use of LMWH, little is known of their safety in patients undergoing radiology interventions. Differences between LMWH and unfractionated heparin and the implications of these differences on use of LMWH in the setting of radiological interventions are outlined. 相似文献
97.
BACKGROUND: Fetal programming of adult disease may be a long-term effect of fetal nutrition. Expected short-term effects include changes in body size and proportions at birth. The specific responses of fetal growth to acute undernutrition at varying points in pregnancy are still unclear. METHODS: We abstracted all birth records of infants born in two midwife training schools in the western Netherlands between 1 October 1944 and 31 March 1946, and compared infants whose mothers were exposed to the Dutch famine of 1944-1945 during specific trimesters of pregnancy with control infants born in 1943. We considered birthweight (BWT), crown-to-heel length (CHL), head circumference (HC), and ratio and regression-adjusted measures of these parameters. RESULTS: BWT, CHL, and HC declined with famine exposure late in pregnancy. Changes in WT for CHL paralleled changes in WT alone in size and direction. Results for HC were inconsistent, varying by choice of body size adjustor (WT or CHL), and by method of adjustment (ratio or regression). BWT, CHL, and HC did not change with first trimester famine exposure. CONCLUSION: Even under famine conditions, birth size and body proportions vary only with late pregnancy exposure. HC for body size has the added disadvantage that late pregnancy exposure effects vary drastically with choice of measure. We do not recommend the use of birth size or body proportions as a proxy for fetal nutritional status in the study of adult disease. 相似文献
98.
BACKGROUND: This study evaluated the effects of severe undernutrition during adolescence and subsequent colon carcinoma risk. METHODS: The authors evaluated The Netherlands Cohort Study on Diet and Cancer (NLCS) among 62,573 women and 58,279 men aged 55-69 years at baseline. Information on diet and risk factors was collected by questionnaire in 1986. Additional information was collected concerning residence during the hunger winter (1944-1945), the World War II years (1940-1944), and father's employment status during the economic depression of 1932-1940, which were used as indicators of exposure. After 7.3 years of follow-up, 807 colon carcinoma cases (388 females and 419 males) were available for analysis. RESULTS: Multivariate analysis showed that both men and women who had lived in a western city in 1944-1945 had a decreased colon carcinoma risk (men: relative risk [RR] = 0.85, 95% confidence interval [CI] = 0.62-1.16; women: RR = 0.80, 95% CI = 0.59-1.09). No association between colon carcinoma risk and urban versus rural residence was found during the war years (1940-1944). Having an unemployed father during the economic depression (1932-1940) was also associated with a small decrease in colon carcinoma risk for men (RR = 0.90, 95% CI =0.62-1.31) and women (RR = 0.75, 95% CI 0.49-1.14). In subgroup analyses, a decreased colon carcinoma risk for men and women who were in their adolescent growth spurt and living in a western city during the hunger winter of 1944-1945 was noted (men: RR = 0.72, 95% CI = 0.31-1.65; women: RR = 0.88, 95% CI = 0.40-1.96). No associations were statistically significant because of the limited study size. CONCLUSIONS: In the current study, a weak inverse relation was found between energy restriction early in life and subsequent colon carcinoma risk for men and women. However, these findings need replication in a larger study. 相似文献
99.
氧瓶燃烧-紫外分光光度法测定硒灵胶囊中硒的含量 总被引:3,自引:0,他引:3
目的:控制本品中硒的含量。方法:采用氧瓶燃烧法使本样品中的主要成份硒酯多糖成四阶硒离子,并与2,3-二氨基萘(DNA)络合生成4,5-苄苯并硒二唑,然后采用紫外分光光度法测定其含量,结果:硒的浓度在0.2~2.0μg/ml之间线性范围良好。结论:该法具有简便,快速,准确的优点。 相似文献
100.
Elevated levels of intact parathyroid hormone (iPTH) are not uncommon after renal transplantation, and this disturbance may affect renal allograft function. This study investigated whether iPTH levels were related to histopathological findings of acute rejection in kidney graft biopsies. Thirty-eight renal transplant recipients (29 males, nine females; mean age 29.5±10.3years) were studied. Renal allograft biopsy was performed in each case to investigate increased creatinine levels. Lymphocyte and macrophage infiltration of the interstitium was evaluated immunohistochemically with monoclonal antibodies to CD3 and CD68. Expression of HLA-DR and fibronectin were also studied. The proportion of interstitial cell staining was graded semiquantitatively. Serum calcium, phosphorus and iPTH levels before and after the renal transplantation were compared. Patients were grouped according to their stabilized iPTH levels at 3 months post-transplantation. Group I ( n =13) exhibited persistently elevated iPTH levels (levels elevated since surgery), and Group II ( n =25) showed persistently low-normal iPTH levels. The mean age of the Group I patients was significantly lower, and their serum calcium levels post-transplantation were significantly higher than those in Group II ( P =0.02 and P =0.03, respectively). Persistent elevation of iPTH was strongly associated with interstitial T-cell density, macrophage density, and glomerular fibronectin expression in the renal allograft biopsies ( P <0.05). Also, the time to fibrosis was significantly shorter in Group I ( P =0.02). The study revealed that PTH has a potent immunomodulatory effect, and that persistent hyperparathyroidism has a significant impact on renal allograft outcome. The data indicate that the serum iPTH level is a valuable indicator of immune response, and that regular monitoring of serum iPTH levels is essential after renal transplantation. 相似文献