全文获取类型
收费全文 | 731篇 |
免费 | 53篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 30篇 |
妇产科学 | 8篇 |
基础医学 | 61篇 |
口腔科学 | 11篇 |
临床医学 | 65篇 |
内科学 | 151篇 |
皮肤病学 | 11篇 |
神经病学 | 74篇 |
特种医学 | 159篇 |
外科学 | 53篇 |
综合类 | 33篇 |
预防医学 | 13篇 |
眼科学 | 4篇 |
药学 | 93篇 |
中国医学 | 6篇 |
肿瘤学 | 19篇 |
出版年
2023年 | 7篇 |
2021年 | 5篇 |
2019年 | 8篇 |
2018年 | 6篇 |
2016年 | 22篇 |
2015年 | 47篇 |
2014年 | 17篇 |
2013年 | 20篇 |
2012年 | 15篇 |
2011年 | 20篇 |
2010年 | 30篇 |
2009年 | 30篇 |
2008年 | 21篇 |
2007年 | 14篇 |
2006年 | 11篇 |
2005年 | 18篇 |
2004年 | 12篇 |
2003年 | 9篇 |
2002年 | 13篇 |
2001年 | 11篇 |
2000年 | 12篇 |
1999年 | 11篇 |
1998年 | 23篇 |
1997年 | 44篇 |
1996年 | 34篇 |
1995年 | 29篇 |
1994年 | 22篇 |
1993年 | 21篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 13篇 |
1989年 | 25篇 |
1988年 | 24篇 |
1987年 | 12篇 |
1986年 | 18篇 |
1985年 | 21篇 |
1984年 | 13篇 |
1983年 | 18篇 |
1982年 | 16篇 |
1981年 | 7篇 |
1980年 | 16篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1976年 | 6篇 |
1974年 | 6篇 |
1972年 | 5篇 |
1971年 | 5篇 |
1970年 | 3篇 |
1968年 | 3篇 |
排序方式: 共有794条查询结果,搜索用时 0 毫秒
81.
目的探讨后路椎间盘镜下腰椎间盘摘除术(MED)及传统开放腰椎间盘摘除术对腰椎生物力学稳定性的影响。方法选用6具新鲜尸体脊柱标本,模拟后路腰椎间盘摘除的不同术式,依次对标本腰3~4间隙进行处理,共设计5种减压情况:MED、半椎板切除、半椎板切除并下关节突1/2切除、半椎板切除并下关节突全部切除和全椎板切除髓核摘除术。在力学实验机上分别对实验标本进行前屈/后伸、左/右侧屈及左/右轴向旋转运动,测量不同运动的最大范围。结果模拟MED手术脊柱标本向各个方向的运动与正常对照组比较差异无统计学意义(P>0.05);半椎板切除术、半椎板切除并下关节突1/2切除后,标本向各个方向的运动除半椎板切除并下关节突1/2切除后右侧旋转外与正常对照组差异无统计学意义(P>0.05),半椎板切除并下关节突全部切除后,标本向各个方向运动与正常对照组比较差异均有统计学意义(P<0.05,右侧旋转P<0.01);模拟全椎板切除标本向各个方向的运动与正常对照组比较差异均有统计学意义(P<0.01)。结论MED手术对脊柱破坏性较小,对稳定性无影响,而半椎板并小关节切除则破坏了稳定性。 相似文献
82.
血府逐瘀汤对乳鼠心肌细胞缺血再灌注损伤的影响 总被引:4,自引:0,他引:4
目的为探讨血府逐瘀汤对乳鼠心肌细胞缺血再灌注损伤的影响。方法应用培养的乳鼠心肌细胞造成缺血再灌注损伤的动物模型,观察心肌细胞中超氧化物岐化酶(SOD)的水平,推断细胞内活性氧的生成量;观察培养液中乳酸脱氢酶(LDH)活性改变以判断细胞损伤情况;并进行DNA琼脂糖凝胶电泳及末端脱氧核苷酸介导的脱氧尿苷三磷酸缺口末端标记法(TUNEL),以判断细胞死亡类型及程度。结果血府逐瘀汤可显著升高缺血再灌注时SOD的水平,显著降低LDH的水平。DNA电泳图谱表明:血府逐瘀汤可使DNA的拖尾基本消失;TUNEL显示血府逐瘀汤可显著减少缺血再灌注所致的心肌细胞死亡。结论血府逐瘀汤有保护缺血再灌注时心肌细胞免于死亡之功效。 相似文献
83.
The peroral pneumocolon examination 总被引:3,自引:0,他引:3
84.
85.
V. V. Myllylä K. A. Sotaniemi J. Tuominen E. H. Heinonen 《Acta neurologica Scandinavica》1989,80(S126):177-182
Abstract– We are carrying out a double-blind parallel trial comparing the effect of selegiline monotherapy and placebo in de novo parkinsonian patients. Fifty-six patients (28 in both groups) are included in the trial. This interim analysis reports the results of the first 52 evaluable patients who have had at least one follow-up visit after entering the trial. The efficacy of treatment was assessed using the Columbia University Rating Scale, the North-Western University Disability Scale and the Webster Rating Scale and followed until the addition of levodopa therapy became necessary. The data were analysed at follow-up times of up to twelve months (34 patients evaluable at the end of the period). The overall disability scores of all the rating scales used were significantly smaller in the selegiline group than in the placebo group. Levodopa treatment had become necessary in 12 patients (46%) in the selegiline group and in 14 patients (54%) in the placebo group. The side-effects were mild and similar in both treatment groups. According to the present results selegiline monotherapy seems to have therapeutic efficacy in the early phase of Parkinson's disease. Whether selegiline is able to slow down the progression of Parkinson's disease needs further clarification. 相似文献
86.
87.
88.
Studies on the mechanism of bacterial resistance to complement-mediated killing. II. C8 and C9 release C5b67 from the surface of salmonella minnesota S218 because the terminal complex does not insert into the bacterial outer membrane 总被引:22,自引:2,他引:22 下载免费PDF全文
The mechanism for consumption of terminal complement components and release of bound components from the surface of serum-resistant salmonella minnesota S218 was studied. Consumption of C8 and C9 by S218 occurred through interaction with C5b67 on the bacterial surface because C8 and C9 were consumed when added to S218 organisms previously incubated in C8-deficient serum and washed to remove all C5b67 on the bacterial surface because C8 and C9 were consumed when added to S218 organisms previously incubated in C8- deficient serum and washed to remove al but cell bound C5b67. Rapid release of (125)I C5 and (125)I C7 from the membrane of S218 was dependent on binding of C8 because (125)I C5 and (125)I C7 deposition in C8D serum was stable and was twofold higher in C8D than in PNHA, and addition of purified C8 or C8 and C9 to S218 previously incubated in C8D serum caused rapid release of (125)I C5 and (125)I C7 from the organism. Analysis by sucrose density gradient ultracentrifugation of the fluid phase from the reaction of S218 and 10 percent PNHS revealed a peak consistent with SC5b-9, in which the C9:C7 ratio was 3.3:1, but the NaDOC extracted bound C5b-9 complex sedimented as a broad peak with C9:C7 of less than 1.2:1. Progressive elution of C5b67 and C5b-9 from S218 but not serum-sensitive S. minnesota Re595 was observed with incubation in buffers of increasing ionic strength. Greater than 90 percent of the bound counts of (125)I C5 or (125)I C9 were released from S218 by incubation in 0.1 percent trypsin, but only 57 percent of (125)I C9 were released by treatment of Re595 with trypsin. These results are consistent with the concept that C5b-9 forms on the surface of the serum-sensitive S. minnesota S218 in normal human serum, but the formed complex is released and is not bactericidal for S218 because it fails to insert into hydrophobic outer membrane domains. 相似文献
89.
A perfluorocarbon blood substitute, Fluosol, is undergoing clinical trials as an adjunct to chemotherapy. The adverse effects associated with its administration have been postulated to result from complement activation. When gel electrophoresis and Western blotting of Fluosol are used after its incubation with serum, activated C3 and factors Bb and H are bound to the Fluosol particles in a time-dependent fashion, which suggests that complement activation with Fluosol, as does that with zymosan, occurs on the surface of the particles. Paradoxically, it is found, both by the measurement of Fluosol-bound C3d and by fluid-phase C5a, that lower concentrations of Fluosol cause greater amounts of complement activation, which suggests a complex interaction of activators and inhibitors that changes as the available surface area is decreased. Studies performed with bystander red cell-bound C3d demonstrated in vivo complement activation occurring in six patients receiving Fluosol as an adjunct to chemotherapy for colon cancer. In two patients, there was a marked increase in red cell-bound C3d after Fluosol infusion; these two patients also developed adverse reactions during Fluosol infusion. These studies suggest that the Fluosol surface plays a major role in the initiation and regulation of complement activation that is seen during Fluosol infusion. 相似文献
90.