全文获取类型
收费全文 | 1306篇 |
免费 | 137篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 75篇 |
妇产科学 | 27篇 |
基础医学 | 153篇 |
口腔科学 | 65篇 |
临床医学 | 135篇 |
内科学 | 286篇 |
皮肤病学 | 19篇 |
神经病学 | 101篇 |
特种医学 | 222篇 |
外科学 | 159篇 |
综合类 | 19篇 |
一般理论 | 2篇 |
预防医学 | 67篇 |
眼科学 | 23篇 |
药学 | 62篇 |
中国医学 | 1篇 |
肿瘤学 | 59篇 |
出版年
2021年 | 12篇 |
2020年 | 13篇 |
2019年 | 29篇 |
2018年 | 29篇 |
2017年 | 11篇 |
2016年 | 17篇 |
2015年 | 32篇 |
2014年 | 36篇 |
2013年 | 46篇 |
2012年 | 44篇 |
2011年 | 51篇 |
2010年 | 33篇 |
2009年 | 41篇 |
2008年 | 38篇 |
2007年 | 60篇 |
2006年 | 50篇 |
2005年 | 44篇 |
2004年 | 35篇 |
2003年 | 22篇 |
2002年 | 36篇 |
2001年 | 30篇 |
2000年 | 29篇 |
1999年 | 30篇 |
1998年 | 51篇 |
1997年 | 43篇 |
1996年 | 42篇 |
1995年 | 34篇 |
1994年 | 56篇 |
1993年 | 30篇 |
1992年 | 29篇 |
1991年 | 20篇 |
1990年 | 19篇 |
1989年 | 51篇 |
1988年 | 53篇 |
1987年 | 49篇 |
1986年 | 39篇 |
1985年 | 29篇 |
1984年 | 28篇 |
1983年 | 19篇 |
1982年 | 13篇 |
1981年 | 9篇 |
1980年 | 10篇 |
1979年 | 10篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1975年 | 6篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1970年 | 11篇 |
1969年 | 7篇 |
排序方式: 共有1487条查询结果,搜索用时 15 毫秒
1.
Increased risk of cancer at multiple sites after gastric surgery for peptic ulcer. 总被引:9,自引:1,他引:8 下载免费PDF全文
Of 5018 patients who had undergone gastric surgery at St James Hospital, Balham, at least 25 years ago, death certificates have been received for 2768, whilst 1746 patients are still alive and are flagged (Office of Populations, Censuses and Surveys (OPCS) will notify us of their death and its cause) and only 504 could not be traced. Mortality from cancers of various organs has been determined using a 'years at risk' calculation in five year bands. There was no increase in mortality risk from any cancers during the first 15 postoperative years, but from 20 years after operation there was a significant excess risk not only of cancer of the stomach (4.5-fold), but also of the large bowel (1.6-fold), bronchus (3.9-fold), pancreas (4.0-fold), biliary tract (9.1-fold), oesophagus (2.3-fold), bladder (2.4-fold), breast (4.0-fold), and cancer of all sites (3.3-fold). These findings are consistent with the production in the operated-upon stomach of circulating carcinogens with a 20 year latency period. 相似文献
2.
3.
4.
SUMMARY A case congenital dislocation of both knees and dislocation of the left hip in an infant whose mother had a chronic amniotic fluid leakage after mid-trimester amniocentesis. 相似文献
5.
6.
高效液相色谱法测定右旋儿茶素血浆浓度及药代动力学参数 总被引:1,自引:0,他引:1
本文建立了体液中右旋儿茶素的RP-HPLC测定方法。采用C_(18)键合相硅胶为填料的固相提取柱进行样品预处理,右旋儿茶素的提取回收率为79.8%.应用二极管阵列检测器对色谱峰纯度进行鉴定。该法精密度好,方法回收率近100%,日内、日间的变异系数为2.4~5.6%,血浓69.6~1160 ng/ml范围内呈线性关系,r=0.9993。家兔静注右旋儿茶素18mg/kg,其药代动力学过程符合二室模型,分布相半衰期为0.129 h,消除相半衰期为1.19h。 相似文献
7.
石杉碱甲类似物的研究II.N-甲基吡啶酮石杉碱甲类似物的合成 总被引:4,自引:1,他引:3
石杉碱甲(1)是从中草药石杉属植物千层塔(Lycopodium serratum Thunb.)中分得的一种高效可逆的乙酰胆碱酯酶抑制剂,临床试验证实它对早老性痴呆症有显著疗效。本文报道N-甲基吡啶酮石杉碱甲类似物2和3的合成。2-甲氧基-5-甲氧羰基-11-亚甲基-5,9-甲撑环辛-7-烯并吡啶(9)在乙腈中用三甲基氯硅烷和碘化钠选择性脱保护以定量的产率得吡啶酮10,再用甲醇钠和碘甲烷甲基化得N-甲基吡啶酮11,11经碱性水解,Curtius重排和氨基的脱保护得N-甲基吡啶酮石杉碱甲类似物2。通过类似的途径从中间体2-甲氧基-5-甲氧羰基-7-甲基-11-酮-5,9-甲撑环辛-7-烯并吡啶(14)合成了类似物3。类似物2和3的乙酰胆碱酯酶抑制活性均低于天然石杉碱甲。 相似文献
8.
9.
Howard B. Yeon Jacob Weinberg Vincent Arlet Jean A. Ouelett Kirkham B. Wood 《European spine journal》2007,16(9):1379-1385
Fifteen skeletally immature patients with double major adolescent idiopathic scoliosis with large lumbar curves and notable L4 and L5 coronal plane obliquity were retrospectively studied. Seven patients who underwent anterior release and fusion of the lumbar curve with segmental anterior instrumentation and subsequent posterior instrumentation ending at L3 were compared with eight patients treated with anterior release and fusion without anterior instrumentation followed by posterior instrumentation to L3 or L4. At 4.5 years follow-up (range 2.5-7 years), curve correction, coronal balance and fusion rate were not statistically different between the two groups; however, the group with anterior instrumentation had improved coronal plane, near normalangulation in the distal unfused segment compared with the group without anterior instrumentation. In cases involving severe lumbar curvatures in the context of double major scoliosis, when as a first stage anterior release is chosen, the addition of instrumentation appears to restore normal coronal alignment of the distal unfused lumbar segment, and may in certain cases save a level compared with traditional fusions to L4. 相似文献
10.
Mutations in the retinal guanylate cyclase (RETGC-1) gene in dominant cone-rod dystrophy 总被引:3,自引:0,他引:3
Kelsell RE; Gregory-Evans K; Payne AM; Perrault I; Kaplan J; Yang RB; Garbers DL; Bird AC; Moore AT; Hunt DM 《Human molecular genetics》1998,7(7):1179-1184
The dominant cone-rod dystrophy gene CORD6 has previously been mapped to
within an 8 cM interval on chromosome 17p12-p13. The retinal- specific
guanylate cyclase gene (RETGC-1), which maps to within this genetic
interval and previously was implicated in Leber's congenital amaurosis, was
screened for mutations within this family and in a panel of small families
and individuals with various cone and cone- rod dystrophy phenotypes. A
missense mutation (E837D) was identified in affected members of the CORD6
family, as well as a second missense mutation (R838C) in three other
families with dominant cone-rod dystrophy. RETGC-1 is only the fourth gene
to be implicated in cone-rod dystrophy and this is the first report of
dominant mutations in this gene.
相似文献