全文获取类型
收费全文 | 1222篇 |
免费 | 84篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 82篇 |
妇产科学 | 11篇 |
基础医学 | 106篇 |
口腔科学 | 36篇 |
临床医学 | 118篇 |
内科学 | 297篇 |
皮肤病学 | 22篇 |
神经病学 | 25篇 |
特种医学 | 243篇 |
外科学 | 92篇 |
综合类 | 59篇 |
预防医学 | 68篇 |
眼科学 | 20篇 |
药学 | 67篇 |
中国医学 | 12篇 |
肿瘤学 | 43篇 |
出版年
2022年 | 3篇 |
2021年 | 6篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 18篇 |
2017年 | 13篇 |
2016年 | 11篇 |
2015年 | 21篇 |
2014年 | 42篇 |
2013年 | 65篇 |
2012年 | 37篇 |
2011年 | 37篇 |
2010年 | 45篇 |
2009年 | 65篇 |
2008年 | 42篇 |
2007年 | 57篇 |
2006年 | 39篇 |
2005年 | 39篇 |
2004年 | 28篇 |
2003年 | 18篇 |
2002年 | 24篇 |
2001年 | 15篇 |
2000年 | 16篇 |
1999年 | 16篇 |
1998年 | 79篇 |
1997年 | 53篇 |
1996年 | 63篇 |
1995年 | 44篇 |
1994年 | 51篇 |
1993年 | 45篇 |
1992年 | 15篇 |
1991年 | 5篇 |
1990年 | 16篇 |
1989年 | 45篇 |
1988年 | 29篇 |
1987年 | 27篇 |
1986年 | 19篇 |
1985年 | 12篇 |
1984年 | 16篇 |
1983年 | 15篇 |
1982年 | 14篇 |
1981年 | 20篇 |
1980年 | 13篇 |
1979年 | 8篇 |
1978年 | 9篇 |
1977年 | 16篇 |
1976年 | 8篇 |
1975年 | 11篇 |
1973年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有1315条查询结果,搜索用时 15 毫秒
71.
Gobbo-Neto L Santos MD Kanashiro A Almeida MC Lucisano-Valim YM Lopes JL Souza GE Lopes NP 《Planta medica》2005,71(1):3-6
The Brazilian medicinal plant Lychnophora ericoides is commercially available as an analgesic and anti-inflammatory agent. The phytochemical investigation of the leaf polar extract yielded 6,8-di-C-beta-glucosylapigenin (1) and the new compound 6,8-di-C-beta-glucosylchrysin (2). 6,8-Di- C-beta-glucosylapigenin (1) showed significant anti-inflammatory activity in the carrageenan-induced rat paw edema. We did not observe any statistical difference between the two compounds (1 and 2) in inhibiting chemiluminescence in opsonized zymosan-stimulated polymorphonuclear leukocytes, suggesting that the anti-inflammatory property of 6,8-di- C-beta-glucosylapigenin (1) is not related to its antioxidant activity. 相似文献
72.
73.
Background
In 2002, the World Health Organization published a health system performance ranking for 191 member countries. The ranking was based on five indicators, with fixed weights common to all countries.Methods
We investigate the feasibility and desirability of using mathematical programming techniques that allow weights to vary across countries to reflect their varying circumstances and objectives.Results
By global distributional measures, scores and ranks are found to be not very sensitive to changes in weights, although differences can be large for individual countries.Conclusions
Building the flexibility of variable weights into calculation of the performance index is a useful way to respond to the debates and criticisms appearing since publication of the ranking. 相似文献74.
Ventral hernia repair: a study of current practice 总被引:5,自引:5,他引:0
Ventral wall hernias are common; despite this, there are no guidelines on the best surgical management. The aim of this study
was to examine the types of repair in use for abdominal wall hernias in the West of Scotland over a 3-month period. Data were
gathered on 120 patients. There were 60 incisional, 32 umbilical, and 28 epigastric hernias. The main indication for repair
was pain (78%), while 12 patients (10%), presented acutely with incarceration or strangulation. The most common method of
repair was sutured (55%), followed by mesh (29%) and Mayo repair (16%). There was no correlation between use of mesh and hernia
size or whether repair was for a recurrent hernia. Surgical practice varies widely in the repair of ventral wall hernias.
Clinical trials are required to establish the best method of repair for this common condition.
Electronic Publication 相似文献
75.
目的构建人端粒酶逆转录酶(hTERT)片段的真核表达质粒。方法用RT-PCR方法从肝癌组织中提取总RNA扩增出hTERT基因片段,将其连接pGEM-TEasy质粒上,将重组质粒pGEM-T-hTERT和pEGFP-C3真核绿色荧光蛋白表达载体同时用HindⅢ和BamHⅠ双酶切后进行连接,再将重组的pEGFP-C3-hTERT基因片段转染NIH3T3细胞,经G418筛选获得稳定转染的细胞系,荧光倒置显微镜观察并检测转染细胞的hTERTmRNA表达水平。结果DNA序列分析证实了重组载体pGEM-T-hTERT和pEGFP-C3-hTERT内插入片段的碱基组成与公开发表的hTERT序列一致。转染pEGFP-C3-hTERT的NIH3T3细胞可见绿色荧光,并检出高水平表达的hTERT。结论成功构建高效表达hTERT的真核表达载体,为以hTERT为靶点的肿瘤治疗打下实验基础。 相似文献
76.
通过探讨细化药品采购环节:包括建立和完善采购制度,优选药品配送企业,制定合理的采购时间、合理采购价格和合理的库存结构及库存水平。以便及时、准确地为临床用药提供安全、有效、经济的药品以及全方位保障药品供应。 相似文献
77.
78.
The cellular mechanisms of coronary vasospasm are unclear, and a role for protein kinase C (PKC) activation by the endogenous vasoconstrictors endothelin-1 (ET-1) and prostaglandin F2alpha (PGF2alpha) has been suggested. In this study, we developed a phorbol ester-induced PKC downregulation protocol to investigate the relation between the amount and activity of specific PKC isoforms in coronary arterial smooth muscle and coronary vasoconstriction by ET-1 and PGF2alpha. Isometric tension was measured in deendothelialized porcine coronary artery strips, [Ca2+]i was monitored in single coronary smooth muscle cells loaded with fura-2, and the whole tissue, cytosolic, and particulate fractions were examined for PKC activity and reactivity with isoform-specific anti-PKC antibodies using Western blot analysis. In Ca(2+)-free (2 mM EGTA) Krebs solution, ET-1 (10(-7) M), PGF2alpha (10(-5) M) and PKC activator phorbol 12,13-dibutyrate (PDBu) (10(-6) M) caused significant contractions that were completely inhibited by the PKC inhibitors staurosporine and calphostin C, no significant change in [Ca2+]i, and significant activation and translocation of the Ca(2+)-independent epsilon-PKC but not the Ca(2+)-dependent alpha-PKC. In Ca(2+)-free Krebs, a single application of PDBu produced maximal contraction and PKC activity after 30 min, which declined to basal levels in 3 h and remained steady for 24 h, but did not prevent subsequent increases in contraction and PKC activity with a new addition of PDBu and did not significantly decrease the amount of alpha- or epsilon-PKC. Repeated (five to eight) applications of PDBu in Ca(2+)-free Krebs at 3-h intervals completely inhibited subsequent increases in contraction and PKC activity to PDBu, ET-1, or PGF2alpha, and significantly decreased the amount of epsilon-PKC but not that of alpha-PKC. These results provide evidence that a Ca(2+)-independent coronary vasoconstriction induced by ET-1 and PGF2alpha is associated with activation of the epsilon-PKC isoform. The results suggest that, in coronary artery smooth muscle, downregulation of PKC is isoform specific and is more dependent on the frequency rather than the duration of PKC activation. The results also suggest that repeated downregulation of epsilon-PKC might play a role in preconditioning of the coronary artery against vasoconstriction by ET-1 and PGF2alpha. 相似文献
79.
80.
由于治疗方法的进步,近80%的儿童和青少年癌症患者能够长期生存。在美国,约有270000例儿童癌症的幸存者,即每640名20至39岁成年人中就有一名幸存者。大量的幸存者有利于儿童癌症治疗后长期健康结果的研究。现在可以明确的是,化疗和放疗所致的儿童各器官系统损害在临床上可能潜伏多年。为了全面了解治疗儿童癌症而继发的健康问题,重要的是衡量三项长期结果:健康状况、死亡率和患病率。这三项中,关于前两项已有相当好的研究报道。在一项对20227例癌症5年生存者的回顾性分析中,Mertens等发现以下原因导致的超额死亡率具有统计学意义:继发癌症(… 相似文献