全文获取类型
收费全文 | 127463篇 |
免费 | 10597篇 |
国内免费 | 5767篇 |
专业分类
耳鼻咽喉 | 1063篇 |
儿科学 | 4196篇 |
妇产科学 | 2993篇 |
基础医学 | 15080篇 |
口腔科学 | 3178篇 |
临床医学 | 11799篇 |
内科学 | 19078篇 |
皮肤病学 | 1813篇 |
神经病学 | 10011篇 |
特种医学 | 2486篇 |
外国民族医学 | 36篇 |
外科学 | 11673篇 |
综合类 | 20374篇 |
现状与发展 | 19篇 |
预防医学 | 10683篇 |
眼科学 | 3392篇 |
药学 | 11498篇 |
39篇 | |
中国医学 | 4506篇 |
肿瘤学 | 9910篇 |
出版年
2024年 | 331篇 |
2023年 | 1526篇 |
2022年 | 3433篇 |
2021年 | 4478篇 |
2020年 | 3920篇 |
2019年 | 3635篇 |
2018年 | 3525篇 |
2017年 | 4067篇 |
2016年 | 4357篇 |
2015年 | 4450篇 |
2014年 | 7742篇 |
2013年 | 8902篇 |
2012年 | 7740篇 |
2011年 | 8708篇 |
2010年 | 7299篇 |
2009年 | 6870篇 |
2008年 | 7125篇 |
2007年 | 7203篇 |
2006年 | 6459篇 |
2005年 | 5805篇 |
2004年 | 4876篇 |
2003年 | 4240篇 |
2002年 | 3545篇 |
2001年 | 3133篇 |
2000年 | 2667篇 |
1999年 | 2294篇 |
1998年 | 1939篇 |
1997年 | 1733篇 |
1996年 | 1603篇 |
1995年 | 1430篇 |
1994年 | 1223篇 |
1993年 | 988篇 |
1992年 | 887篇 |
1991年 | 712篇 |
1990年 | 695篇 |
1989年 | 538篇 |
1988年 | 415篇 |
1987年 | 380篇 |
1986年 | 312篇 |
1985年 | 465篇 |
1984年 | 375篇 |
1983年 | 253篇 |
1982年 | 340篇 |
1981年 | 223篇 |
1980年 | 202篇 |
1979年 | 141篇 |
1978年 | 119篇 |
1977年 | 104篇 |
1976年 | 97篇 |
1973年 | 77篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Sung Hee Chung Olof Heimbürger Bengt Lindholm Hi Bahl Lee 《Nephrology, dialysis, transplantation》2005,20(6):1207-1213
BACKGROUND: Dialysis patient mortality remains high, and this high mortality may be due to many factors. In peritoneal dialysis (PD) patients, old age, co-morbid diseases, malnutrition, low residual renal function (RRF) and a high peritoneal transport rate have been shown to influence survival, but the relative importance of these factors may differ between different patient populations. Besides, centre practice patterns may differ between centres and may influence patient survival. In addition, the literature suggests that dialysis patient survival may be better in Asian than in Caucasian patients. METHODS: The influence of centre and patient characteristics on patient survival was investigated in 132 Korean and 106 Swedish incident PD patients, who underwent initial biochemical measurements and assessment of adequacy of dialysis, nutritional status, RRF and peritoneal transport characteristics. RESULTS: At the start of PD, Korean patients had a higher prevalence of diabetes, peritoneal Kt/V(urea), peritoneal creatinine clearance and peritoneal fluid removal, and lower body mass index, RRF and dialysate to plasma creatinine concentration ratio (D/P Cr) compared with Swedish patients. Significantly more patients from Korea were placed on temporary haemodialysis before PD (100 out of 132) when compared with Swedish patients (21 out of 106). During the follow-up, there was a significantly higher rate of transfer to other units in Korea and a significantly higher rate of kidney transplantation in Sweden. On Kaplan-Meier analysis, overall patient survival did not differ and relative risk for death was also not different between the two centres even after adjustment for age, diabetes, cardiovascular disease, RRF and D/P Cr. On Cox proportional hazards multivariate analysis, age, diabetes, RRF and D/P Cr were found to be independent predictors of mortality in the combined cohort of patients. While age, diabetes and D/P Cr were independent predictors of mortality in Korean patients, age and RRF independently predicted mortality in Swedish patients. CONCLUSION: Although there were significant differences in centre and patient characteristics, we were unable to confirm a survival advantage for Korean over Swedish PD patients. The results of this study suggest that the reported difference in survival between Asian and Caucasian dialysis patients may have been due, in part, to differences in centre and patient characteristics rather than to race as such. The genetic influence on patient characteristics remains, however, to be elucidated. 相似文献
52.
周围神经端侧动脉套接后神经再生的研究 总被引:6,自引:2,他引:4
目的研究周围神经端侧动脉套接后神经再生的可能性及其特点. 方法取SD大鼠75只,在股骨中下段切断腓神经,将近断端逆转90度包埋于肌肉中.随机分为5组.A组:将截取的左颈总动脉套接于右侧正常胫神经侧方与腓总神经远端2 mm距离之间,缝合部胫神经外膜不予切除;B组:在胫神经套接部外膜开窗1.0 mm;C组:腓总神经切断14天后再予动脉套接,余同B组;D组:同B组,且于动脉套接部注入神经生长因子(neural growth factor, NGF)1 ml;E组:将腓总神经远端以端侧缝合形式直接缝合于胫神经的一侧,外膜开窗1.0 mm.术后4、8和12周分别行组织学、电镜和神经纤维计数等检查. 结果 4周时C、D及E组周边区域有神经纤维轴突和髓鞘再生,A组则无神经纤维生长; 8周时C、D及E组再生神经纤维较B组多,E组神经纤维较C、D组多,差异有统计学意义(P<0.05); 12周时C、D及E组神经纤维多于B组,差异有统计学意义(P<0.05);C组及D组有较丰富的神经再生,与神经端侧直接吻合的E组差异无统计学意义(P>0.05). 结论神经端侧2 mm距离动脉套接可作为修复周围神经损伤的一种可行方法. 相似文献
53.
目的 研究腹腔内注射三氧化二砷(arsenic trioxide,As2O3)对小鼠CO2气腹下肝癌H22转移的影响. 方法 昆明鼠40只(清洁级),中腹部穿刺置入1 mm套管针,自套管针注入1×106肿瘤细胞后,建立CO2气腹,压力8 mm Hg,时间30 min.术后随机分4组,每组10只,分别腹腔内注入生理盐水,1 ml;As2O3(2 mg/kg),1 ml;As2O3(4 mg/kg),1 ml;As2O3(4mg/kg)+肝素(10 U/ml),共1 ml.气腹后第3、7天测量肿瘤黏附因子(CD44)、血管内皮生长因子(vascular endothelial growth factor,VEGF)的变化;比较各组生存状态、腹围、体重变化及转移瘤直径.结果 气腹后第3、7天,与对照组相比,各As2O3组CD44、VEGF表达均明显降低(P<0.05).2个高剂量组的气腹后第3天VEGF、第7天CD44比低剂量组降低明显(P<0.05).4组戳口种植率分别为9/10、8/10、7/10、6/10,差异无显著性(x2=2.667,P=0.446). 结论 As2O3对CO2气腹腹腔镜肿瘤生长转移有抑制作用. 相似文献
54.
55.
目的制备胶原蛋白一明胶神经支架材料(CG材料)并研究其在修复大鼠10mm坐骨神经缺损实验中的疗效。方法以I型胶原蛋白、明胶通过冷冻干燥技术制备具有轴向微管结构的神经支架材料,用其桥接修复sD大鼠坐骨神经10mm缺损。术后16周分别行透射电镜,S-100、β-tubulin class Ⅲ、NFl60免疫荧光染色以及电生理检测,观察支架材料引导神经再生的疗效。结果制备的材料内部为孔径均匀且平行排列的微管结构,术后16周通过透射电镜和免疫荧光染色可见大量再生神经纤维,电生理检测神经传导速度及波幅接近自体神经移植。结论胶原蛋白一明胶支架材料能够有效的促进周围神经再生。 相似文献
56.
Robert M. Levy Roman Saikovsky Evgeniya Shmidt Alexander Khokhlov Bruce P. Burnett 《Nutrition Research》2009
Flavocoxid (Limbrel), a proprietary mixture of flavonoid molecules (baicalin and catechin), was tested against a traditional nonsteroidal anti-inflammatory drug, naproxen, for the management of the signs and symptoms of moderate osteoarthritis (OA) in humans. Discomfort and global disease activity were used as the primary end points, and safety assessments were also taken for both treatments as a secondary endpoint. In this double-blind study, 103 subjects were randomly assigned to receive either flavocoxid [500 mg twice daily (BID)] or naproxen (500 mg BID) in a 1-month onset of action trial. Outcome measures included the short Western Ontario and McMaster University Osteoarthritis Index, subject Visual Analogue Scale for discomfort and global response, and investigator Visual Analogue Scale for global response and fecal occult blood. Both flavocoxid and naproxen showed significant reduction in the signs and symptoms of knee OA (P ≤ .001). There were no statistically detectable differences between the flavocoxid and naproxen groups with respect to any of the outcome variables. Similarly, there were no statistically detectable differences between the groups with respect to any adverse event, although there was a trend toward a higher incidence of edema and nonspecific musculoskeletal discomfort in the naproxen group. In this short-term pilot study, flavocoxid was as effective as naproxen in controlling the signs and symptoms of OA of the knee and would present a safe and effective option for those individuals on traditional nonsteroidal anti-inflammatory drugs or cyclooxygenase-2 inhibitors. A low incidence of adverse events was reported for both groups. 相似文献
57.
目的探讨碱性成纤维细胞生长因子(bFGF)不同剂量、用药方法对扩张组织的影响.方法以白色家猪为实验动物,采用持续恒压扩张技术,观察不同剂量和不同给药时间,bFGF和硫糖铝对扩张组织的影响及组织结构变化.结果扩张术同时每日2次局部应用bFGF 9AU/cm2 硫糖铝100μg/ml,共7 d,浸于明胶海绵上缓慢持续释放对扩张组织的影响最明显,效果最佳,扩张器内实际注液量、扩张所获得的皮肤净增面积明显增加,皮瓣回缩率降低.表皮细胞层数增多,胶原纤维、弹力纤维、成纤维细胞密度和毛细血管密度显著增高.药量增加效果未随之增加.结论持续恒压扩张术时合用bF-GF 9AU/cm2 硫糖铝100μg/ml,每日2次注药浸入明胶海绵持续缓慢释放效果最佳. 相似文献
58.
碱性成纤维细胞生长因子在实验性硬脑膜重建中的应用 总被引:3,自引:0,他引:3
[目的] 探讨碱性成纤维细胞生长因子( bFGF)在实验性自体筋膜硬脑膜重建中的应用价值.[方法]取 SD大鼠 35只,分成 5组.其中 A组 3只,直接将背部筋膜覆盖在硬膜外, B组 5只,采用自体筋膜硬脑膜重建模型,通过免疫组织化学方法观察这两组大鼠自体筋膜硬脑膜移植的愈合过程及细胞因子 bFGF在其中的表达; C组、 D组、 E组各 9只,分别进行自体筋膜硬脑膜重建, D组加用外源性 bFGF, E组仅用明胶海绵,通过脑脊液漏研究、免疫组织化学方法研究外源性 bFGF对自体筋膜重建硬脑膜愈合过程的影响并用 RT- PCR方法研究内源性 bFGF mRNA的表达情况.[结果] 大鼠自体筋膜移植硬脑膜部位 bFGF表达明显; C、 D、 E组大鼠重建硬脑膜抵抗脑脊液漏压力值( mmH2O)分别为 311± 75, 497± 153, 338± 88,Ⅰ型胶原纤维表达值分别为 4.9± 0.8, 10.9± 1.6, 5.3± 0.9, D组均好于对照组( P< 0.05);内源性 bFGF mRNA的表达没有明显变化.[结论] 在自体筋膜移植硬脑膜的愈合过程中 bFGF可能起了重要的作用;外源性 bFGF处理的大鼠其移植筋膜愈合要好于对照组. 相似文献
59.
Relaxin down-regulates renal fibroblast function and promotes matrix remodelling in vitro. 总被引:1,自引:0,他引:1
Rosemary Masterson Tim D Hewitson Kristen Kelynack Marina Martic Laura Parry Ross Bathgate Ian Darby Gavin Becker 《Nephrology, dialysis, transplantation》2004,19(3):544-552
BACKGROUND: Renal fibroblasts are important effector cells in tubulointerstitial fibrosis, with experimental antifibrotic strategies focusing on the functional down-regulation of these cells. Several experimental models of fibrosis have provided evidence for the effectiveness of the polypeptide hormone relaxin as a potential antifibrotic agent. This study was conducted to further elucidate the antifibrotic mechanisms of relaxin on renal fibroblasts in vitro. METHODS: Rat cortical fibroblasts were obtained from outgrowth culture of renal tissue isolated from kidneys 3 days post-unilateral ureteric obstruction and constituted 100% of cells studied. A relaxin radio-receptor assay was used to establish binding of relaxin to renal fibroblasts in vitro. Functional studies then examined the effects of H2 relaxin (0, 1, 10 and 100 ng/ml) on fibroblast kinetics, expression of alpha-smooth muscle actin (alpha-SMA), total collagen synthesis, collagenase production and collagen-I lattice contraction. CTGF mRNA expression was also measured by northern analysis. RESULTS: H2 relaxin bound with high affinity to rat renal fibroblasts, but receptor numbers were low. Consistent with its previously reported bimodal effect, transforming growth factor (TGF-beta 1) reduced fibroblast proliferation, an effect abrogated by H2 relaxin. Fibroblasts exposed to H2 relaxin (100 ng/ml) for 24 h demonstrated decreased immunostaining for alpha-SMA and reduced alpha-SMA protein expression compared with controls. There was a trend for a relaxin-mediated reduction in total collagen synthesis and alpha 1(I) mRNA expression with large dose-related increases in collagenase protein expression being observed. TGF-beta 1-stimulated collagen-I lattice contraction was significantly inhibited following co-incubation with 100 ng/ml relaxin. Incremental doses of H2 relaxin had no significant effect on CTGF mRNA expression. CONCLUSIONS: The findings of this study suggest that the antifibrotic effects of relaxin involve down-regulation of fibroblast activity, increase in collagenase synthesis and restructuring of collagen-I lattices, which are consistent with its known physiological role of matrix remodelling. Although there appears to be an interaction between TGF-beta 1 and H2 relaxin, this does not appear to involve a reduction in CTGF mRNA expression. 相似文献
60.
目的:观察转移因子口服液佐治小儿单纯性肾病综合征的疗效。方法:将75例诊断为单纯性肾病综合征的患儿随机分为治疗组和对照组,对照组主要采用泼尼松口服治疗,治疗组另加用转移因子口服液治疗。观察两组的感染率、复发率及治疗前后血IgG、IgA水平。结果:治疗组的感染率和复发率明显较低;治疗后血IgG、IgA水平明显提高,与对照组比较差异明显(P〈0.01)。结论:转移因子口服液佐治小儿单纯性肾病综合征可以降低患者的感染率和复发率,提高血IgG和IgA水平,是治疗肾病综合征的有效方法之一。 相似文献