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   5811篇
  免费   321篇
  国内免费   28篇
耳鼻咽喉   106篇
儿科学   112篇
妇产科学   111篇
基础医学   802篇
口腔科学   478篇
临床医学   366篇
内科学   1329篇
皮肤病学   122篇
神经病学   577篇
特种医学   83篇
外科学   670篇
综合类   19篇
一般理论   1篇
预防医学   623篇
眼科学   59篇
药学   433篇
中国医学   74篇
肿瘤学   195篇
  2023年   53篇
  2022年   95篇
  2021年   209篇
  2020年   132篇
  2019年   166篇
  2018年   215篇
  2017年   134篇
  2016年   192篇
  2015年   189篇
  2014年   274篇
  2013年   312篇
  2012年   465篇
  2011年   506篇
  2010年   264篇
  2009年   173篇
  2008年   359篇
  2007年   325篇
  2006年   307篇
  2005年   253篇
  2004年   212篇
  2003年   179篇
  2002年   146篇
  2001年   133篇
  2000年   126篇
  1999年   101篇
  1998年   30篇
  1997年   24篇
  1996年   16篇
  1995年   28篇
  1993年   15篇
  1992年   57篇
  1991年   57篇
  1990年   39篇
  1989年   50篇
  1988年   36篇
  1987年   31篇
  1986年   20篇
  1985年   25篇
  1984年   13篇
  1983年   16篇
  1978年   15篇
  1977年   9篇
  1975年   15篇
  1974年   11篇
  1973年   14篇
  1971年   11篇
  1970年   11篇
  1969年   13篇
  1968年   16篇
  1967年   10篇
排序方式: 共有6160条查询结果,搜索用时 15 毫秒
71.
72.
73.
ObjectiveTo identify the urban phlebotomine sandfly fauna in Ponta Porã, Mato Grosso do Sul State, Brazil.MethodsThe captures were undertaken from April 2009 to March 2010 with CDC light traps in 14 ecotopes (intra and peridomicile) in different areas of the city, Shannon traps being used in areas with abundant vegetation.ResultsA total of 707 specimens were captured with CDC light traps (565 males and 142 females) and 155 specimens (112 males and 43 females) with Shannon traps, a total of 862 phlebotomines. The specimens captured belonged to eight species: Lutzomyia longipalpis (Lutz & Neiva, 1912), Evandromyia cortelezzii (Brethes, 1923), Sciopemyia sordelli (Shannon & Del Ponte, 1927), Pintomyia pessoai (Coutinho & Barretto, 1940); Pintomyia monticola (Costa Lima, 1932); Brumptomyia brumpti (Larousse, 1920); Nyssomyia whitmani (Antunes & Coutinho, 1939) and Psathyromyia shannoni (Dyar, 1929). Lutzomyia longipalpis, the main vector of Leishmania (Leishmania) chagasi, was the species most frequently captured (97.03%) and also the most abundant according to the standardized abundance index (SAI)=0.86.ConclusionsThe highest species richness was captured, with CDC light traps, inside the domiciles and the species diversity and evenness in the peridomicile, clearly indicating a preference for anthropic environments.  相似文献   
74.
75.
76.
This study evaluated the effects of the isolated use of a low dose of methyltestosterone (MT) on cardiovascular reflexes and hormonal levels and its geno‐ and cytotoxic safety in ovariectomized rats. Female Wistar rats were divided into four groups (n = 6), respectively: SHAM (received vehicle methylcellulose 0.5%), SHAM + MT (received MT 0.05 mg/kg), OVX (received vehicle), and OVX + MT (received MT). Twenty‐one days after ovariectomy, treatment was given orally daily for 28 days. The Bezold–Jarisch reflex (BJR) was analyzed by measuring the bradycardic and hypotensive responses elicited by phenylbiguanide (PBG) administration. The baroreflex sensitivity (BRS) was evaluated by phenylephrine and sodium nitroprussite. Myocyte hypertrophy was determined by morphometric analysis of H&E stained slides. Biochemical data were analyzed, as well as micronucleus assay. MT improved BRS and increased testosterone values, but did not change estradiol in the OVX group. MT did not promote changes in mean arterial pressure, heart rate, BJR, serum concentrations of troponin I, weight and histopathology of the heart. MT was able to restore the BRS in OVX rats. The geno‐ and cytotoxic safety of the MT was demonstrated by the absence of an increase in the micronucleus (PCEMN) or change in the ratio between normochromatic erythrocytes and polychromatic erythrocytes (NCE/PCE).  相似文献   
77.
78.
79.
Context: The combination of antibiotics with natural products has demonstrated promising synergistic effects in several therapeutic studies.

Objective: The aim of this study was to determine the effect of a combination of an ethanol extract of Myracrodruon urundeuva Fr. All. (Anacardiaceae) (aroeira plant) and its essential oil with six antimicrobial drugs against multiresistant strains of Staphylococcus aureus and Escherichia coli from clinical isolates.

Materials and methods: After identification of the chemical components by GC-MS, the antibacterial activity of the natural products and antibiotics was assessed by determining the minimal inhibitory concentration (MIC) using the microdilution method and concentrations ranging 8–512?μg/mL and 0.0012–2.5?mg/mL, respectively. Assays were performed to test for a possible synergistic action between the plant products and the antimicrobials, using the extract and the oil at a sub-inhibitory concentration (128?μg/mL) and antibiotic at concentrations varying between 8 and 512?μg/mL.

Results: The GC-MS analysis identified the main compound as δ-carene (80.41%). The MIC of the natural products was >1024?μg/mL, except against S. aureus ATCC25923. Only the combinations of the natural products with gentamicin, amikacin and clindamycin were effective against S. aureus 358, enhancing the antibiotic activity by reducing the MIC.

Conclusions: The extract from aroeira showed a higher antibacterial activity and the oil was more effective in potentiating the activity of conventional antibiotics.  相似文献   
80.
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