全文获取类型
收费全文 | 2439篇 |
免费 | 139篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 24篇 |
儿科学 | 51篇 |
妇产科学 | 40篇 |
基础医学 | 254篇 |
口腔科学 | 87篇 |
临床医学 | 184篇 |
内科学 | 560篇 |
皮肤病学 | 38篇 |
神经病学 | 129篇 |
特种医学 | 44篇 |
外科学 | 463篇 |
综合类 | 38篇 |
预防医学 | 176篇 |
眼科学 | 53篇 |
药学 | 299篇 |
中国医学 | 29篇 |
肿瘤学 | 115篇 |
出版年
2023年 | 21篇 |
2022年 | 65篇 |
2021年 | 107篇 |
2020年 | 49篇 |
2019年 | 71篇 |
2018年 | 78篇 |
2017年 | 31篇 |
2016年 | 50篇 |
2015年 | 48篇 |
2014年 | 89篇 |
2013年 | 110篇 |
2012年 | 145篇 |
2011年 | 157篇 |
2010年 | 68篇 |
2009年 | 74篇 |
2008年 | 124篇 |
2007年 | 137篇 |
2006年 | 118篇 |
2005年 | 136篇 |
2004年 | 110篇 |
2003年 | 82篇 |
2002年 | 61篇 |
2001年 | 45篇 |
2000年 | 55篇 |
1999年 | 46篇 |
1998年 | 14篇 |
1997年 | 15篇 |
1995年 | 10篇 |
1994年 | 12篇 |
1993年 | 14篇 |
1992年 | 33篇 |
1991年 | 33篇 |
1990年 | 34篇 |
1989年 | 34篇 |
1988年 | 32篇 |
1987年 | 17篇 |
1986年 | 24篇 |
1985年 | 23篇 |
1984年 | 23篇 |
1983年 | 18篇 |
1981年 | 11篇 |
1979年 | 21篇 |
1978年 | 12篇 |
1977年 | 12篇 |
1976年 | 9篇 |
1975年 | 11篇 |
1974年 | 16篇 |
1973年 | 13篇 |
1972年 | 8篇 |
1968年 | 9篇 |
排序方式: 共有2584条查询结果,搜索用时 15 毫秒
1.
2.
Purpose: To describe how central venous access devices (CVADs) are utilized for ambulatory oncology patients and to evaluate the rate of complications. Method: Single institution retrospective study of oncology patients with CVADs who received systemic treatment at the Walker Family Cancer Centre (WFCC) between 1 January and 31 December 2018. Results: A total of 480 CVADS were placed in 305 patients, of which 408 (85%) were peripherally inserted central catheters (PICCs) and 72 (15%) were implanted vascular access devices (PORTs). The incidence of early and late complications was 9% and 24%, respectively. For the entire cohort, the rate of venous thromboembolism (VTE) was 16%, of which 9% were CVAD-related thrombosis (CRTs) and 7% were distant VTE. The CRT rates were similar for PICCs and PORTs (9% vs. 7%). A total of 6% of CVADs were complicated by infection (i.e., localized infections and bacteremia), with a total infection rate of 0.43 and 0.26 per 1000 indwelling days for PICCs and PORTs, respectively. The incidence of central line associated bloodstream infections (CLABSI) was greater for PICCs than PORTs, at a rate of 0.22 compared with 0.08 per 1000 indwelling days, respectively. The premature catheter removal rate was 26% for PICCs and 18% for PORTs. PORTs required more additional hospital visits. Conclusions: PICCs were utilized more frequently than PORTs and had a higher rate of premature removal. The rates of VTE and CRT were similar for both CVAD types. PORTs had a lower rate of infection per 1000 indwelling days. However, the management of PORT related complications required more visits to the hospital and oncology clinic. 相似文献
3.
BackgroundExcessive consumption of ethanol is known to activate the mTORC1 pathway and to enhance the Collapsin Response Mediator Protein-2 (CRMP-2) levels in the limbic region of brain. The latter helps in forming microtubule assembly that is linked to drug taking or addiction-like behavior in rodents. Therefore, in this study, we investigated the effect of lacosamide, an antiepileptic drug and a known CRMP-2 inhibitor, which binds to CRMP-2 and inhibits the formation of microtubule assembly, on ethanol-induced conditioned place preference (CPP) in mice.MethodsThe behavior of mice following ethanol addiction and withdrawal was assessed by performing different behavioral paradigms. Mice underwent ethanol-induced CPP training with alternate dose of ethanol (2 g/kg, po) and saline (10 ml/kg, po). The effect of lacosamide on the expression of ethanol-induced CPP and on ethanol withdrawal associated anxiety and depression-like behavior was evaluated. The effect of drug on locomotor activity was also assessed and hippocampal CRMP-2 levels were measured.ResultsEthanol-induced CPP was associated with enhanced CRMP-2 levels in the hippocampus. Lacosamide significantly reduced the expression of ethanol-induced CPP and alleviated the levels of hippocampal CRMP-2 but aggravated withdrawal-associated anxiety and depression in mice.ConclusionThe present study demonstrated the beneficial effect of lacosamide in attenuation of expression of ethanol induced conditioned place preference via reduction of hippocampal CRMP-2 level. These findings suggest that lacosamide may be investigated further for ethanol addiction but not for managing withdrawal. 相似文献
4.
PTH fragments consisting of the C-terminal portion of the molecule may have biologic effects and may modify the actions of PTH. Evidence for the presence of a C-terminal PTH receptor further supports a biologic role for such fragments. Because C-PTH fragments accumulate in patients with renal insufficiency, it is possible that they may contribute to renal bone disease. The precise role of circulating C-PTH fragments in the pathogenesis, diagnosis, and management of renal osteodystrophy, however, remains to be determined. Future studies of the biologic effects and regulation of these fragments may lead to better understanding of skeletal biology and may also improve our approach to the diagnosis and treatment of renal bone disease. 相似文献
5.
Fahim Zaman Atta Nawabi Kenneth D Abreo Gazi B Zibari 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2005,9(3):262-265
Laparoscopic procedures continue to gain popularity over traditional open procedures for a number of abdominal and pelvic surgeries. With increasing experience, the application of this technique is rising because it provides an alternative, less invasive, approach to various surgical procedures. Herein, we report our experience with adult patients with polycystic kidney disease, requiring bilateral laparoscopic nephrectomy before renal transplantation. 相似文献
6.
T. Fahim G. A. Böhmig M. Exner N. Huttary H. Kerschner S. Kandutsch D. Kerjaschki A. Bramböck K. Nagy-Bojarszky H. Regele 《American journal of transplantation》2007,7(2):385-393
Accumulation of inflammatory cells within capillaries is a common morphologic feature of humoral renal allograft rejection and is most easily appreciated if it occurs in glomeruli. The aim of our study was to determine the amount and composition of immune cells within glomeruli and peritubular capillaries (PTC) in cellular and humoral allograft rejection. Immunofluorescent double-labeling for CD31 and CD3 or CD68 was used for phenotyping and enumerating immune cells within glomeruli and PTC. The major findings are: (1) accumulation of immune cells in PTC is far more common than it would be anticipated based on the assessment by conventional histology; (2) it is not the absolute number of immune cells accumulating within capillaries, but rather the composition of the intracapillary cell population that distinguishes humoral rejection from cellular rejection and (3) in C4d positive biopsies a predominantly monocytic cell population accumulates not only within glomeruli but also within PTC. The median value of monocyte/T-cell ratio within PTC was 2.3 in C4d positive biopsies but only 1 (p = 0.0008) in C4d negative biopsies. Given their prominent presence within capillaries and their extensive biological versatility monocytes might contribute to the capillary damage observed in acute and chronic allograft rejection. 相似文献
7.
This work is dedicated to the memory of the late Dr Ian Walker. 相似文献
8.
Campylobacter jejuni has been documented as one of the major aetiological agents of diarrhoeal illness all over the world. Studies revealed its pathogenicity by different assay methods, but none could be strongly recommended as a tool for differentiating toxigenic strains of C. jejuni. This study was an attempt to demonstrate better its pathogenicity by media modification. Fifteen isolates of C. jejuni recovered from diarrhoeal patients at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka Hospital were included in this study. The standard medium for C. jejuni was modified by the incorporation of FeCl3 at different concentrations. The pathogenicity of the test isolates were studied by rabbit ileal loop assay; Chinese hamster ovary (CHO), human epithelial cervical carcinoma (HeLa); Y-1 adrenal cell lines and suckling mouse assay. Sonicated extracts of the test organisms, grown with FeCl3 supplement, were also assayed. An enhanced growth of C. jejuni was obtained with the increasing concentration of FeCl3 supplementation in the medium. Only five isolates of C. jejuni produced cytotoxic effect on HeLa cell monolayer. Other cell lines were not affected by the test specimens or sonicates. Rabbit ileal loop assay did not reveal any fluid accumulation but on dissection, the test loops were found highly haemorrhagic. No heat-stable (ST) toxin could be detected. Cell-free culture supernatant of patients' isolates of C. jejuni had an effect on HeLa cell monolayer. Sonicated extracts of patients' extracts had a greater effect on HeLa cell monolayer. Pathogenic strains of C. jejuni might be distinguished on HeLa cell monolayer using its sonicated extracts. 相似文献
9.
Summary It has been suggested that age changes in the morphology of the neuromuscular junction (NMJ) may reflect altered physical activity levels rather than the unique effects of ageing. Additionally, previous studies have indicated that the structure of the NMJ may be modulated with exercise. To investigate these questions, quantitative morphometry was determined on soleus and extensor digitorum longus (EDL) nerve terminals stained with zinc iodide-osmium from C57BL/6NNia mice under control and endurance exercised conditions at 12, 18 and 24 months of age.As previously observed, the area, perimeter, extent length and branch number of nerve terminals increased with age in both soleus and EDL. The changes were similar between the muscle types, although the changes were more pronounced in the phasic EDL. In 12-month-old animals, 2 months of endurance exercise resulted in significantly larger nerve terminals in both soleus and EDL, suggesting a functional adaptation. Exercised 18- and 24-month-old nerve terminals were smaller than corresponding controls, which indicated that exercise minimized or prevented further age-related nerve terminal elaboration. At all ages the exercised nerve terminals comprised a more homogeneous population than corresponding controls, which indicates that uniform physical activity can modulate NMJ morphometry. The magnitude of the changes suggests that subtle alterations in normal cage activity with advancing age do not have a significant effect on the morphology of nerve terminals. However, the morphology of the NMJ does change significantly in response to physical exercise training. 相似文献
10.
Congenital duodenal obstruction. 总被引:3,自引:0,他引:3
Over the period 1980-1989, 49 patients with congenital duodenal obstruction due to duodenal atresia, duodenal stenosis or annular pancreas were treated. There were three deaths, all related to associated severe congenital anomalies and none related to surgery for duodenal obstruction; 78 per cent of the patients had associated congenital anomalies which, in some instances, complicated their management. Prenatal diagnosis by ultrasonography was made in 18 per cent of the patients and these patients had operations relatively earlier. 相似文献