全文获取类型
收费全文 | 2124篇 |
免费 | 114篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 103篇 |
妇产科学 | 110篇 |
基础医学 | 175篇 |
口腔科学 | 46篇 |
临床医学 | 214篇 |
内科学 | 491篇 |
皮肤病学 | 48篇 |
神经病学 | 53篇 |
特种医学 | 178篇 |
外科学 | 183篇 |
综合类 | 143篇 |
一般理论 | 1篇 |
预防医学 | 143篇 |
眼科学 | 13篇 |
药学 | 150篇 |
1篇 | |
中国医学 | 73篇 |
肿瘤学 | 113篇 |
出版年
2021年 | 19篇 |
2020年 | 14篇 |
2019年 | 12篇 |
2018年 | 18篇 |
2017年 | 20篇 |
2016年 | 22篇 |
2015年 | 42篇 |
2014年 | 56篇 |
2013年 | 58篇 |
2012年 | 85篇 |
2011年 | 79篇 |
2010年 | 72篇 |
2009年 | 62篇 |
2008年 | 67篇 |
2007年 | 62篇 |
2006年 | 56篇 |
2005年 | 36篇 |
2004年 | 47篇 |
2003年 | 29篇 |
2002年 | 35篇 |
2001年 | 43篇 |
2000年 | 43篇 |
1999年 | 43篇 |
1998年 | 54篇 |
1997年 | 56篇 |
1996年 | 53篇 |
1995年 | 55篇 |
1994年 | 62篇 |
1993年 | 40篇 |
1992年 | 30篇 |
1991年 | 36篇 |
1990年 | 24篇 |
1989年 | 37篇 |
1988年 | 42篇 |
1987年 | 35篇 |
1986年 | 34篇 |
1985年 | 18篇 |
1984年 | 23篇 |
1983年 | 23篇 |
1982年 | 21篇 |
1981年 | 27篇 |
1980年 | 19篇 |
1959年 | 37篇 |
1958年 | 58篇 |
1957年 | 87篇 |
1956年 | 45篇 |
1955年 | 75篇 |
1954年 | 67篇 |
1953年 | 16篇 |
1952年 | 14篇 |
排序方式: 共有2253条查询结果,搜索用时 0 毫秒
1.
David M. Presby Michael C. Rudolph Vanessa D. Sherk Matthew R. Jackman Rebecca M. Foright Kenneth L. Jones Julie A. Houck Ginger C. Johnson Janine A. Higgins P. Darrell Neufer Robert H. Eckel Paul S. MacLean 《Diabetes》2021,70(4):867
Moderate weight loss improves numerous risk factors for cardiometabolic disease; however, long-term weight loss maintenance (WLM) is often thwarted by metabolic adaptations that suppress energy expenditure and facilitate weight regain. Skeletal muscle has a prominent role in energy homeostasis; therefore, we investigated the effect of WLM and weight regain on skeletal muscle in rodents. In skeletal muscle of obesity-prone rats, WLM reduced fat oxidative capacity and downregulated genes involved in fat metabolism. Interestingly, even after weight was regained, genes involved in fat metabolism were also reduced. We then subjected mice with skeletal muscle lipoprotein lipase overexpression (mCK-hLPL), which augments fat metabolism, to WLM and weight regain and found that mCK-hLPL attenuates weight regain by potentiating energy expenditure. Irrespective of genotype, weight regain suppressed dietary fat oxidation and downregulated genes involved in fat metabolism in skeletal muscle. However, mCK-hLPL mice oxidized more fat throughout weight regain and had greater expression of genes involved in fat metabolism and lower expression of genes involved in carbohydrate metabolism during WLM and regain. In summary, these results suggest that skeletal muscle fat oxidation is reduced during WLM and regain, and therapies that improve skeletal muscle fat metabolism may attenuate rapid weight regain. 相似文献
2.
宫腹腔镜联合手术诊治不孕症150例分析 总被引:14,自引:0,他引:14
目的:探讨宫腹腔镜联合手术在诊治不孕症中的应用。方法:对150例不孕症患者行宫腹腔镜联合手术,对不孕症病因进行诊断,同时行治疗。结果:盆腔粘连和输卵管阻塞是不孕症的主要原因。子宫内膜息肉和正常盆腔占次要比例。子宫内膜异位症和多囊卵巢也是主要病因。150例同时行宫腹腔镜输卵管通液和各种疾病的治疗。联合手术后妊娠率为48.8%。结论:腹腔镜联合手术,在一次麻醉下,可以对不孕的原因全面评价和明确诊断,在诊断同时进行治疗,对不孕症的诊断和治疗有重大的意义,值得推广。 相似文献
3.
Needle-localized breast biopsy: why do we fail? 总被引:10,自引:0,他引:10
4.
5.
6.
Acute respiratory distress during Caesarean section under spinal anaesthesia A probable case of anaphylactoid reaction to Syntocinon 总被引:2,自引:0,他引:2
A case of life-threatening respiratory distress during a Caesarean section under spinal anaesthesia is reported. Possible causes of the event including anaphylactoid reactions and the methods of their diagnosis are discussed. The most likely cause of the episode was felt to be an anaphylactoid reaction to Syntocinon. 相似文献
7.
Abstract: This paper dicusses the use of esophageal dilatation with a Rigiflex TTS balloon. This method was used 45 times on 11 patients affected by anastomotic or a severe grade peptic esophageal stenosis. Fluoroscopic guidance was used in 36 procedures (80%) without effecting the mean duration of the treatment (12 minutes). The results were considered satisfactory when these goals had been achieved: a) dilatation of the stenosis over 15 mm; b) a dysphagia free-time of more than 6 months. A satisfactory result was achieved in 10 patients (90.9%), without deaths and major complications. 5 patients received 1 dilatation and the other 5 needed, 3-3-4-7–11 procedures respectively to obtain a satisfactory result. On these basis we consider that its great efficacy, security and tolerability depend on the following characteristics of the Rigiflex TTS balloon: 1) “radial” dilatation; 2) the possibility of introducing the balloon through the operative channel of the fiberscope; 3) direct visualization of the stenosis during dilatation. The following disadvantages with this method are: the absence of a tactile sensation of dilatation and the elevated cost of the instrument. We conclude that the Rigiflex TTS balloon is an important alternative to guide-wire techniques, especially for the treatment of severe esophageal strictures. 相似文献
8.
妊娠肝内胆汁淤积症患者血清一氧化氮和内皮素的变化及意义 总被引:2,自引:0,他引:2
目的:探讨妊娠肝内胆汁淤积症(ICP)患者外周静脉血清、新生儿脐静脉血清中一氧化氮(NO)、内皮素(ET)、丙二醛(MDA)和超氧化物歧化酶(SOD)含量的变化及在ICP发病中的作用。方法:以ICP组28例为研究组,测定其外周静脉血清及新生儿脐静脉血清中的NO、ET、MDA和SOD,以年龄相近的24例正常孕妇作为对照组。结果:ICP患者的MDA和ET含量较正常晚期妊娠显著增高(P<0.01),ICP患者的NO和SOD含量与对照组相比无显著性差异(P>0.05)。母血清中NO、ET、MDA含量均较新生儿脐静脉血清中的含量高,差异有显著性(P<0.01)。结论:妊娠期体内氧化和抗氧化失衡及ET水平的增高可能与ICP的发生、发展有关。 相似文献
9.
B M O'Connor A L Jackman P H Crossley S E Freemantle J Lunec A H Calvert 《Cancer research》1992,52(5):1137-1143
We describe the characterization of human lymphoblastoid cell lines with acquired resistance (greater than 20,000-fold) to a novel folate-based thymidylate synthase (TS) (EC 2.1.1.45) inhibitor, C2-desamino-C2-methyl-N10-propargyl-5,8-dideazafolic acid (ICI198583). This acquired resistance was associated with a 64-fold amplification of the TS gene, a similar elevation in the corresponding mRNA, and an approximately 200-fold increase in both TS activity and TS protein. This amplification was maintained when the cells were grown in the absence of the selective agent, ICI198583, for 340 generations. TS isolated from one of the resistant cell lines, W1-L2:C1, displayed inhibition kinetic parameters similar to those of TS isolated from the parent W1-L2 cell line. It thus appears unlikely that resistance is due to an altered TS enzyme having a lower affinity for ICI198583. The resistant cell line, W1-L2:C1, was cross-resistant to other folate-based TS inhibitors but was as sensitive as the parent cell line, W1-L2, to 5-fluorodeoxyuridine. The W1-L2:C1 cell line was collaterally sensitive to the classical dihydrofolate reductase (EC 1.5.1.3) inhibitor methotrexate as well as to the lipophilic dihydrofolate reductase inhibitors metoprine and 2,4-diamino-5-methyl-6-[(3,4,5-trimethoxyanilino)methyl]quinazolin e glucuronic acid salt (also called trimetrexate). When the W1-L2 and W1-L2:C1 cell lines were exposed to 1 microM ICI198583 for 24 h they accumulated the same concentration of total cellular ICI198583 polyglutamates despite the fact that the latter cell line accumulated a 300-fold greater concentration of ICI198583 monoglutamate. As polyglutamates, the tetra- and pentaglutamate forms predominated in the W1-L2 cell line, whereas the diglutamate form predominated in the W1-L2:C1 cell line, with few higher polyglutamates being detected. The lack of tri- and higher polyglutamates of ICI198583 (i.e., the more active species) in the W1-L2:C1 cell line may also contribute to the observed resistance. These findings may have important implications in light of the rapid onset of resistance to antifolates in the clinic. 相似文献
10.
We have investigated whether the greater ability of forskolin to activate adenylate cyclase (EC 4.6.1.1) from rat heart compared with rat lung is due to interactions between G-proteins and catalytic units, isoforms of catalytic units or membrane-protein interactions. Interactions between Gs and catalytic units were found to be similar in both tissues with 10 microM Gpp(NH)p increasing activity up to 5-fold. While MnCl2 increased the response of the lung enzyme to forskolin, it reduced the response of the cardiac enzyme and uncoupled Gs from the cardiac catalytic units indicating that Gs interactions potentiate the response to forskolin. After enzyme solubilisation with n-octyl-beta-D-glucopyranoside, the response to forskolin was identical in heart and lung whether assayed with magnesium or manganese chloride, and not significantly different from the heart membrane enzyme. Overall, the results show that the relatively poor response of lung adenylate cyclase to forskolin is due to specific inhibitory interactions between the enzyme and lung membrane constituents. 相似文献