首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   457篇
  免费   32篇
  国内免费   28篇
耳鼻咽喉   3篇
儿科学   13篇
妇产科学   8篇
基础医学   36篇
口腔科学   18篇
临床医学   50篇
内科学   128篇
皮肤病学   8篇
神经病学   20篇
特种医学   47篇
外科学   56篇
综合类   7篇
预防医学   35篇
眼科学   2篇
药学   52篇
中国医学   3篇
肿瘤学   31篇
  2023年   7篇
  2022年   5篇
  2021年   8篇
  2020年   5篇
  2019年   11篇
  2018年   10篇
  2017年   8篇
  2016年   10篇
  2015年   17篇
  2014年   14篇
  2013年   24篇
  2012年   23篇
  2011年   16篇
  2010年   22篇
  2009年   21篇
  2008年   16篇
  2007年   38篇
  2006年   20篇
  2005年   9篇
  2004年   7篇
  2003年   8篇
  2002年   8篇
  2001年   11篇
  2000年   10篇
  1999年   14篇
  1998年   10篇
  1997年   12篇
  1996年   9篇
  1995年   3篇
  1994年   10篇
  1993年   10篇
  1992年   12篇
  1991年   7篇
  1990年   7篇
  1989年   10篇
  1988年   7篇
  1987年   6篇
  1986年   6篇
  1985年   16篇
  1984年   7篇
  1983年   4篇
  1982年   7篇
  1981年   3篇
  1980年   2篇
  1979年   2篇
  1978年   5篇
  1976年   2篇
  1970年   2篇
  1967年   3篇
  1966年   6篇
排序方式: 共有517条查询结果,搜索用时 156 毫秒
21.
Pharmaceutical Chemistry Journal - Azines or di-imines are compounds containing R1R2C=N-N=CR3R4 fragment in its structure. These compounds have received special attention due to their importance as...  相似文献   
22.
In this study, the prevalence, genotype frequency, and risk factors for HBV infection in 768 HIV-infected subjects living in Piauí were determined. Forty-six (6.0 %) HIV-positive subjects were reactive for HBsAg and positive for HBV-DNA. Genotypes A (71.8 %), F (23.9 %) and D (4.3 %) were identified. Multivariate analysis revealed an association between HIV-HBV coinfection and male gender, older age groups, unprotected sex, reporting more than ten sexual partners throughout life, STD, and tattooing. This study shows the importance of monitoring sites and professionals who perform tattooing and practice safe sex to prevent the spread of HIV and HBV infections.  相似文献   
23.
24.
Candidate gene studies have analyzed the effect of specific vitamin D pathway genes on vitamin D availability; however, it is not clear whether genetic variants also affect overall bone metabolism. This study evaluated the association between genetic polymorphisms in GC, CYP2R1 and CYP24A1 and serum levels of total 25(OH)D, iPTH and other mineral metabolism biomarkers (albumin, total calcium and phosphorus) in a sample of 273 older Spanish adults. We observed a significant difference between CYP2R1 rs10741657 codominant model and total 25(OH)D levels after adjusting them by gender (p = 0.024). In addition, the two SNPs in the GC gene (rs4588 and rs2282679) were identified significantly associated with iPTH and creatinine serum levels. In the case of phosphorus, we observed an association with GC SNPs in dominant model. We found a relationship between haplotype 2 and 25(OH)D levels, haplotype 4 and iPTH serum levels and haplotype 7 and phosphorus levels. In conclusion, genetic variants in CYP2R1 and GC could be predictive of 25(OH)D and iPTH serum levels, respectively, in older Caucasian adults. The current study confirmed the role of iPTH as one of the most sensitive biomarkers of vitamin D activity in vivo.  相似文献   
25.
目的:分析国产雷帕霉素洗脱支架治疗急性冠状动脉综合征的安全性和有效性。方法:选择2004-11/2006-02在河北大学附属医院接受冠状动脉介入治疗的急性冠状动脉综合征患者102例,其中ST段抬高型心肌梗死54例,非ST段抬高型心肌梗死28例,不稳定型心绞痛20例。根据血管情况置入国产雷帕霉素药物洗脱支架(Firebird支架),支架选择原则为:支架长度应覆盖病变两端;血管直径:支架直径=1∶1.1。所有患者术前3d均口服阿司匹林100mg,氯吡格雷75mg,术中推注肝素8000 ̄10000U,手术每延迟1h,补充肝素1000u,术后皮下注射低分子肝素5 ̄7d;服用氯吡格雷75mg,1次/d,共服用9 ̄12个月,并长期服用阿司匹林100mg,1次/d。随访情况:术后6个月时随访64例;7个月时随访26例;8个月时随访12例;平均随访6.8个月,患者出院后定期进行门诊随访,记录一般情况及严重心脏不良事件(包括急性、亚急性、迟发支架内血栓形成;再发心肌梗死;急诊冠状动脉旁路移植术;死亡),术后6 ̄8个月行冠状动脉造影评价支架内再狭窄情况。并观察材料及宿主反应。结果:102例患者经皮冠状动脉介入治疗治疗均获得成功,共治疗靶血管102支,置入Firebird支架116枚,术中3例ST段抬高型心肌梗死患者出现无复流现象,2例发生室颤,电转复恢复窦性心律,3例因分支受压,出现心绞痛症状。术后4例出现穿刺部位血肿,经重新加压压迫后好转。随访6 ̄8个月所有患者未发生严重心血管事件;42例(41.2%)患者术后6 ̄8个月行冠状动脉造影复查,无一例发生支架内再狭窄。随访期间所有患者无全身毒性及超敏反应发生,生物相容性好。结论:国产药物洗脱支架治疗急性冠状动脉综合征安全,有效。  相似文献   
26.
27.
28.
Subinhibitory concentrations of bacitracin, vancomycin and other inhibitors of cell wall synthesis reversed to varying extents the intrinsic resistance of Mycobacterium tuberculosis to clarithromycin. Ethambutol reversed clarithromycin resistance in all of the M. tuberculosis strains studied regardless of their susceptibility to this drug.  相似文献   
29.
The theoretical background and experimental evidence of the use of calcium antagonists in the treatment of acute myocardial infarction are summarised. The main clinical trials that have studied the effects of the three different groups of these drugs in patients with myocardial necrosis are then reviewed. Finally, the conclusion is drawn that there is no proof of the efficacy of calcium blockers in the therapy of patients with acute myocardial infarction but that, in some subgroups of these subjects (Q-wave myocardial infarction with good left ventricular function, non Q-wave myocardial infarction), non-dihydropyridinic compounds should be effective, in particular in patients with contraindications to beta-adrenergic blockade.  相似文献   
30.
Antioxidants may play an important role in immune evasion by schistosome parasites. Previous studies have focused on the roles of superoxide dismutase and glutathione S-transferase. In the present study, glutathione peroxidase (GPX) activity was measured in different fractions of worm extracts from several developmental stages of Schistosoma mansoni. The enzyme activity was shown to be developmentally regulated, with higher specific activities being found in the tegument-enriched Nonidet P-40 extract of adult worms (the stage least susceptible to immune killing) than in the larval stages (which are most susceptible to immune elimination). In all extracts tested, the activity against cumene hydroperoxide, even when glutathione S-transferase activity was removed, was higher than that for hydrogen peroxide. The expression of GPX cDNA in pGEX-2T by bacteria produced a 50-kDa fusion protein and a 32-kDa truncated protein. The latter was due to termination at the internal UGA codon that codes for selenocysteine. GPX activity was detected in the recombinantly produced GPX but not with Sj26-glutathione S-transferase from the vector. Mutating the TGA codon to TGT produced a full-length product, GPXm (19 kDa), that was used to produce 19 monoclonal antibodies. Anti-GPXm monoclonal antibodies recognized a 19-kDa molecule in adult-worm extract which, upon removal by immunoprecipitation, resulted in the loss of over 90% of the GPX activity, suggesting that a single form of GPX exists in the schistosome.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号