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   12070篇
  免费   772篇
  国内免费   88篇
耳鼻咽喉   137篇
儿科学   314篇
妇产科学   358篇
基础医学   1416篇
口腔科学   334篇
临床医学   979篇
内科学   2788篇
皮肤病学   219篇
神经病学   548篇
特种医学   363篇
外国民族医学   2篇
外科学   1893篇
综合类   334篇
一般理论   8篇
预防医学   786篇
眼科学   487篇
药学   1111篇
中国医学   128篇
肿瘤学   725篇
  2023年   137篇
  2022年   300篇
  2021年   574篇
  2020年   362篇
  2019年   492篇
  2018年   515篇
  2017年   374篇
  2016年   356篇
  2015年   331篇
  2014年   530篇
  2013年   622篇
  2012年   918篇
  2011年   919篇
  2010年   530篇
  2009年   417篇
  2008年   668篇
  2007年   701篇
  2006年   569篇
  2005年   535篇
  2004年   514篇
  2003年   423篇
  2002年   375篇
  2001年   164篇
  2000年   165篇
  1999年   156篇
  1998年   74篇
  1997年   43篇
  1996年   52篇
  1995年   53篇
  1994年   56篇
  1993年   36篇
  1992年   73篇
  1991年   73篇
  1990年   89篇
  1989年   71篇
  1988年   69篇
  1987年   71篇
  1986年   76篇
  1985年   50篇
  1984年   43篇
  1983年   28篇
  1982年   26篇
  1981年   17篇
  1980年   24篇
  1979年   31篇
  1977年   28篇
  1976年   23篇
  1974年   16篇
  1973年   17篇
  1970年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
132.
目的:牙周疾病非常普遍,尽管有各种特定的治疗方法,但我们始终面临治疗方法有限的问题。考虑到世界组织十分关注传统医学在医疗服务中的发展和应用,我们在一直考察研究伊朗传统医学中药物对牙周疾病的治疗作用。方法:此项研究是一个对有关方面书籍的综合论述,伊朗传统医学内容是经过对重量级作者如Avicenna和Alzahrawy所著的有价值的书籍修订,收集了各医学院校馆藏图书和医药公司的有关信息编辑而成,因为在伊朗传统医学中牙周疾病分成不同目类,对有关药物的研究也被分成8个大组63个题目。(1)缓解牙龈肿胀药物(2)治疗牙龈恶化药物(3)治疗口疮腐烂药物(4)治疗牙龈肥大药物(5)利于伤口康复药物(6)利于牙龈加固的药物(7)阻止牙龈出血的药物(8)防止牙齿松动药物。结果结论:伊朗传统医学在准确的观察和实践的基础上来描述和治疗牙周疾病的。在制药学、有效治疗方面、科学研究手段等领域,伊朗传统医学在以下几个方面可作为现代制药研究的重要资源:(1)纯天然资源(2)容易获得(3)相对比较安全。  相似文献   
133.
134.
135.
Brain-targeted delivery of various drugs can be successfully achieved by chemical delivery systems (CDS) that contain a 1,4-dihydropyridine-based redox targetor moiety and undergo a sequential metabolism. However, the susceptibility of this moiety toward hydration in acidic media may limit the shelf-life of such compounds in aqueous formulation. Here, a systematic investigation of the chemical stability toward oxidation and hydration of ester and amide derivatives of 3-substituted 1,4-dihydropyridine, 1,4-dihydroquinoline, and 4-substituted 1,2-dihydroisoquinoline is reported, together with the in vitro stability and in vivo (rat) distribution of isoquinoline-based testosterone and hydrocortisone chemical delivery systems, which were selected as having the most suitable acid-resistant targetor moieties.  相似文献   
136.
Theileriosis is an economically important hemoprotozoal disease with high morbidity and mortality in cattle. The present study reported the pathological features of a natural outbreak of tropical bovine theileriosis due to Theileria annulata in Fars Province, southern Iran. T. annulata was confirmed by the presence of T. annulata piroplasms in the blood smears and also by polymerase chain reaction test. On necropsy, pale mucous membranes and petechial and ecchymotic hemorrhages in the mucosal and serosal surfaces together with lymphadenopathy were observed. The liver was friable, yellowish, and larger than normal. Hemorrhages and punched-out ulcers were observed in the abomasal mucous membrane. Severe petechial hemorrhages were seen in the skin particularly in the hairless areas. Pulmonary edema and emphysema with petechial and ecchymotic hemorrhagic foci in the lungs were evident. The main histological changes were proliferation of lymphocytes in the lymph nodes and proliferation of macrophages, lymphocytes, and plasma cells in the spleen, Peyer's patches, portal tracts of the liver, and interstitial tissue of the kidneys. The mucous membrane of the abomasum showed numerous multifocal areas of necrosis and ulceration, and the submucosal area and lamina propria adjacent to these lesions showed hyperemia and hemorrhages, with mononuclear cell infiltration. The skin showed multifocal necrotic changes, petechial and ecchymotic hemorrhages, and chronic dermatitis. The schizonts of Theileria were evident in the cytoplasm of the lymphocytes and macrophages of the lymph nodes, spleen, and skin. Molecular examination revealed that these animals were infected with T. annulata. The present study describes the clinicopathological findings of bovine tropical theileriosis in an unpredictable weather condition.  相似文献   
137.
138.
Leptospira immunoglobulin (Ig)-like (Lig) proteins are a novel family of surface-associated proteins in which the N-terminal 630 amino acids are conserved. In this study, we truncated the LigA conserved region into 7 fragments comprising the 1st to 3rd (LigACon1-3), 4th to 7.5th (LigACon4-7.5), 4th (LigACon4), 4.5th to 5.5th (LigACon4.5–5.5), 5.5th to 6.5th (LigACon5.5–6.5), 4th to 5th (LigACon4-5), and 6th to 7.5th (LigACon6-7.5) repeat domains. All 7 recombinant Lig proteins were screened using a slot-shaped dot blot assay for the diagnosis of equine leptospirosis. Our results showed that LigACon4-7.5 is the best candidate diagnostic antigen in a slot-shaped dot blot assay. LigACon4-7.5 was further evaluated as an indirect enzyme-linked immunosorbent assay (ELISA) antigen for the detection of Leptospira antibodies in equine sera. This assay was evaluated with equine sera (n = 60) that were microscopic agglutination test (MAT) negative and sera (n = 220) that were MAT positive to the 5 serovars that most commonly cause equine leptospirosis. The indirect ELISA results showed that at a single serum dilution of 1:250, the sensitivity and specificity of ELISA were 80.0% and 87.2%, respectively, compared to those of MAT. In conclusion, an indirect ELISA was developed utilizing a recombinant LigA fragment comprising the 4th to 7.5th repeat domain (LigACon4-7.5) as a diagnostic antigen for equine leptospirosis. This ELISA was found to be sensitive and specific, and it yielded results that concurred with those of the standard MAT.  相似文献   
139.
140.
目的:评估助视器对年龄相关性黄斑变性(AMD)患者视功能恢复和阅读速度的影响。方法:对低视力门诊44名AMD患者进行评估。收集并分析使用助视器前和使用助视器时裸眼视力、最佳矫正视力、屈光状态、助视器类型(LVAs)以及阅读速度的相关数据。结果:共44例AMD患者,平均年龄为73±10.8岁,男性36例(82%)。其中,29例(67%)受试者视力较好的眼远视力(DVA)为1.0~1.6 LogMAR,而36例(82%)受试者近视力(NVA)小于3.2 m。使用助视器时平均DVA提高0.67±0.27 LogMAR(P=0.000)。使用LVAs时,42例患者NVA达到1 m甚至更佳,仅有2例(4.5%)没有使用LVAs的患者NVA为1 m。在使用一定时间的助视器后,有阅读能力的患者平均阅读速度从每分钟2.9±4.78字提高到每分钟71.31±29.96字(P<0.001)。15名受试者远距离视觉使用单目望远镜,而戴高倍单目镜片眼镜作为最常用的阅读辅助工具。结论:LVAs对AMD患者的视功能恢复和阅读能力的提高有一定的作用。对于AMD患者而言,接受低视力护理服务是有必要的。  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