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   204篇
  免费   22篇
  国内免费   13篇
儿科学   10篇
基础医学   25篇
口腔科学   4篇
临床医学   23篇
内科学   40篇
皮肤病学   24篇
神经病学   4篇
特种医学   9篇
外科学   18篇
综合类   11篇
预防医学   18篇
眼科学   8篇
药学   26篇
肿瘤学   19篇
  2023年   1篇
  2022年   1篇
  2021年   5篇
  2020年   2篇
  2019年   6篇
  2018年   7篇
  2017年   8篇
  2016年   7篇
  2015年   10篇
  2014年   10篇
  2013年   9篇
  2012年   6篇
  2011年   10篇
  2010年   12篇
  2009年   17篇
  2008年   8篇
  2007年   13篇
  2006年   6篇
  2005年   5篇
  2004年   5篇
  2003年   3篇
  2002年   5篇
  2001年   6篇
  1999年   3篇
  1998年   14篇
  1997年   8篇
  1996年   5篇
  1995年   5篇
  1994年   3篇
  1993年   4篇
  1992年   1篇
  1991年   6篇
  1990年   4篇
  1989年   3篇
  1988年   2篇
  1987年   2篇
  1986年   2篇
  1985年   3篇
  1984年   3篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
  1976年   3篇
  1974年   1篇
  1968年   1篇
  1959年   1篇
排序方式: 共有239条查询结果,搜索用时 52 毫秒
81.
本研究应用气相色谱法,测定了我国132位藏族和158位维吾尔族健康志愿者一次口服异喹胍(DB)10mg后8h尿中DB和4-羟异喹胍(4-OH-DB)的含量。结果表明,我国藏族和维族志愿者的DB羟化代谢均具双态性。求得藏及维族DB和4-OH-DB代谢比值的对数值(log MR)的范围分别为-0.70~1.54(MR为0.20~34.32)和-0.89~1.47(MR为0.13~29.73).以log MR=1.10为分界点,132位藏族和158位维族志愿者中分别有2个和1个弱代谢者。其缺陷频率分别为1.52和0.63%。吸烟和性别对DB羟化代谢的MR值无明显影响(P>0.2).服药后8h DB和4-OH-DB的回收率分别为:藏族19.83±10.99和10.81±6.58%;维族22.74±14.41和16.61±10.11%。  相似文献   
82.
粉防己碱对离体大鼠心脏钙反常的保护作用   总被引:2,自引:0,他引:2  
粉防己碱(Tet)能明显抑制离体大鼠心脏钙反常时心肌组织LDH和蛋白的释出,减少无钙灌流时心肌组织Ca~(2+)丢失和Na~+堆积以及复钙灌流时心肌组织Ca~(2+),Na~+堆积和Mg~(2+),K~+丢失,并呈浓度依赖性。此外,钙反常时心肌组织中微量元素Fe,Zn含量下降,Cu含量增加,而Tet可抑制Fe及Zn含量的下降。维拉帕米(Ver)也有类似作用,电镜下,Tet可部分减轻钙反常时心肌组织超微结构的破坏。  相似文献   
83.
84.
Common complications of thoracic radiotherapy include esophagitis and radiation pneumonitis. However, it is important to be aware of uncommon post-radiotherapy complications such as bronchiolitis obliterans organizing pneumonia (BOOP). We report on two patients with carcinoma of the breast who developed an interstitial lung disease consistent with BOOP. BOOP responds to treatment with corticosteroids and the prognosis is generally good despite of the need for long-term administration of corticosteroids as relapses can occur during tapering of steroids. This report provides guidelines for the evaluation and treatment of patients with pulmonary infiltrates after radiotherapy.  相似文献   
85.
From 1976 through 1989, weekly aerial spraying operations against blackflies were carried out along the rivers of a wide savanna area of West Africa (approximately 700,000 km(2)) where onchocerciasis was hyperendemic. The level of endemicity began to decrease significantly after 4 years of vector control and became very low in 1989. This situation has been maintained without any vector control activity or chemotherapy, and no incidence of any new cases has been detected. An ophthalmological study carried out in 2000 has confirmed these good results, showing only cicatricial ocular lesions in the examined population. These results led to the conclusion that 14 years of vector control may achieve long-term elimination of onchocerciasis, even in the absence of chemotherapy, provided that the treated areas are not subjected to any contamination by exogenous parasites carried in infected humans or flies.  相似文献   
86.
Increasing appreciation of tumor heterogeneity and the tumor-host interaction has stimulated interest in developing novel therapies that target both tumor cells and tumor microenvironment. Bone marrow derived cells (BMDCs) constitute important components of the tumor microenvironment. In this study, we aim to investigate the significance of VEGFR1- and VEGFR2-expressing non-tumor cells, including BMDCs, in esophageal cancer (EC) progression and in VEGFR1/VEGFR2-targeted therapies. Here we report that VEGFR1 or VEGFR2 blockade can significantly attenuate VEGF-induced Src and Erk signaling, as well as the proliferation and migration of VEGFR1+ and VEGFR2+ bone marrow cells and their pro-invasive effect on cancer cells. Importantly, our in vivo data show for the first time that systemic blockade of VEGFR1+ or VEGFR2+ non-tumor cells with neutralizing antibodies is sufficient to significantly suppress esophageal tumor growth, angiogenesis and metastasis in mice. Moreover, our tissue microarray study of human EC clinical specimens showed the clinicopathological significance of VEGFR1 and VEGFR2 in EC, which suggest that anti-VEGFR1/VEGFR2 therapies may be particularly beneficial for patients with aggressive EC. In conclusion, this study demonstrates the important contributions of VEGFR1+ and VEGFR2+ non-tumor cells in esophageal cancer progression, and substantiates the validity of these receptors as therapeutic targets for this deadly disease.  相似文献   
87.
88.
We studied the malaria transmission dynamics in Kassena Nankana district (KND), a site in northern Ghana proposed for testing malaria vaccines. Intensive mosquito sampling for 1 year using human landing catches in three micro-ecological sites (irrigated, lowland and rocky highland) yielded 18 228 mosquitoes. Anopheles gambiae s.l. and Anopheles funestus constituted 94.3% of the total collection with 76.8% captured from the irrigated communities. Other species collected but in relatively few numbers were Anopheles pharoensis (5.4%) and Anopheles rufipes (0.3%). Molecular analysis of 728 An. gambiae.s.l. identified Anopheles gambiae s.s. as the most dominant sibling species (97.7%) of the An. gambiae complex from the three ecological sites. Biting rates of the vectors (36.7 bites per man per night) were significantly higher (P<0.05) in the irrigated area than in the non-irrigated lowland (5.2) and rocky highlands (5.9). Plasmodium falciparum sporozoite rates of 7.2% (295/4075) and 7.1% (269/3773) were estimated for An. gambiae s.s. and An. funestus, respectively. Transmission was highly seasonal, and the heaviest transmission occurred from June to October. The intensity of transmission was higher for people in the irrigated communities than the non-irrigated ones. An overall annual entomological inoculation rate (EIR) of 418 infective bites was estimated in KND. There were micro-ecological variations in the EIRs, with values of 228 infective bites in the rocky highlands, 360 in the lowlands and 630 in the irrigated area. Approximately 60% of malaria transmission in KND occurred indoors during the second half of the night, peaking at daybreak between 04.00 and 06.00 hours. Vaccine trials could be conducted in this district, with timing dependent on the seasonal patterns and intensity of transmission taking into consideration the micro-geographical differences and vaccine trial objectives.  相似文献   
89.
Aim: To examine and compare stroke risk factors and their management in stroke patients of Chinese descent versus English‐speaking background (ESB)‐Australian patients. Methods: Cohort study. Fifty‐one Chinese‐Australians and 119 ESB‐Australians who were admitted to hospitals within Sydney metropolitan area with a recent acute ischaemic or haemorrhagic stroke were recruited. Results: Chinese‐Australian patients tended to have a favourable smoking (0% current smokers vs 15%, P = 0.036) and drinking (5% current medium/heavy drinkers vs 17%, P = 0.005) pattern compared with the Australian patients. The prevalence of diabetes mellitus was higher in Chinese‐Australians (31% vs 10%, P = 0.003). The management of hypertension and atrial fibrillation (AF) in Chinese‐Australians was suboptimal (19% untreated hypertension vs 8%, P = 0.102; 78% AF not on Warfarin vs 51%, P = 0.264). Conclusion: The findings of this study suggest that targeting specific stroke prevention strategies may be useful for Chinese‐Australians. Larger‐scale studies need to be conducted to confirm these findings.  相似文献   
90.

Background  

No country is fully prepared for a 1918-like pandemic influenza. Averting a pandemic of H5N1 influenza virus depends on the successful control of its endemicity, outbreaks in poultry and occasional spillage into human which carries a case-fatality rate of over 50%. The use of perimetric depopulation and vaccination has failed to halt the spread of the epidemic. Blanket vaccination for all poultry over a large geographical area is difficult. A combination of moratorium, segregation of water fowls from chickens and vaccination have been proved to be effective in the Hong Kong Special Administrative Region (HKSAR) since 2002 despite endemicity and outbreaks in neighbouring regions. Systematic surveillance in southern China showed that ducks and geese are the primary reservoirs which transmit the virus to chickens, minor poultry and even migratory birds.  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