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   560篇
  免费   34篇
  国内免费   1篇
耳鼻咽喉   5篇
儿科学   38篇
妇产科学   6篇
基础医学   117篇
临床医学   45篇
内科学   93篇
皮肤病学   8篇
神经病学   86篇
特种医学   2篇
外科学   38篇
综合类   20篇
预防医学   38篇
眼科学   5篇
药学   47篇
中国医学   2篇
肿瘤学   45篇
  2023年   6篇
  2022年   9篇
  2021年   19篇
  2020年   16篇
  2019年   16篇
  2018年   17篇
  2017年   12篇
  2016年   16篇
  2015年   20篇
  2014年   15篇
  2013年   24篇
  2012年   33篇
  2011年   45篇
  2010年   31篇
  2009年   15篇
  2008年   34篇
  2007年   16篇
  2006年   34篇
  2005年   26篇
  2004年   20篇
  2003年   22篇
  2002年   20篇
  2001年   12篇
  2000年   5篇
  1999年   7篇
  1998年   5篇
  1997年   6篇
  1996年   3篇
  1995年   3篇
  1994年   3篇
  1992年   5篇
  1991年   3篇
  1990年   3篇
  1988年   2篇
  1987年   5篇
  1986年   2篇
  1985年   2篇
  1979年   10篇
  1977年   5篇
  1976年   4篇
  1975年   4篇
  1974年   2篇
  1973年   3篇
  1972年   3篇
  1971年   2篇
  1970年   11篇
  1969年   4篇
  1968年   5篇
  1966年   1篇
  1958年   1篇
排序方式: 共有595条查询结果,搜索用时 15 毫秒
1.
R Banik  D Lubach 《Dermatologica》1987,174(4):180-183
The relevant literature does not contain detailed numerical data about skin tags. We found 46% skin tag carriers in 750 unselected persons (25% males and 21% females). The risk of getting skin tags increases with age. The age of 50, however, seems to be a turning point, at which a stagnation of the increase is observed. The majority of the carriers had no more than 3 tags per localization; the most frequent localization was the axilla, followed by the neck. This study supplies objective data for the evaluation of skin tags as markers for colonic polyps and may provide standard values for future studies.  相似文献   
2.
Oxygen free radicals (OFR) are implicated in thepathogenesis of stress, chemically induced gastriclesions, and gastrointestinal injury. Theconcentration-dependent scavenging abilities of bismuthsubsalicylate (SBS), colloidal bismuth subcitrate (CBS), andselected OFR scavengers, including superoxide dismutase(SOD), catalase, mannitol, and allopurinol were examinedagainst biochemically or chemically generated superoxide anion, hydroxyl radical, andhypochlorite radical plus hypochlorous acid based on achemiluminescence assay. Furthermore, both gastric (GM)and intestinal mucosa (IM) were individually exposed in vitro to these free radical generatingsystems, and the concentration-dependent protectiveabilities of SBS and CBS against lipid peroxidation (LP)were compared with selected OFR scavengers. In addition, 24-hr fasted rats were orally treated with thenecrotizing agents 0.6 M HCl, 0.2 M NaOH, 80% ethanol,and aspirin (200 mg/kg). The extent of tissue injury inthe GM and IM was determined by assessing LP, DNA fragmentation, and membrane microviscosity.Dose- and time-dependent in vivo protective abilities ofCBS (100 mg/kg) and SBS (15 mg/kg) were also assessed.Following incubations with superoxide anion and hydroxyl radical generating systems in thepresence of 125 mg SBS/liter, approximately 47% and 61%inhibitions were observed in the chemiluminescenceresponse, respectively, while 48% and 46% inhibitions were observed with 125 mg CBS/liter. SBS andCBS exerted similar abilities towards hypochloriteradical plus hypochlorous acid. Approx. 3.1- and3.7-fold increases in LP were observed in the GM and IMof rats following oral administration of 0.6 MHCl. Pretreatment of the rats with SBS and CBS decreased0.6 M HCl-induced LP in the GM by approx. 39% and 27%,respectively, with similar decreases in LP in the IM. SBS exhibited better protectiveabilities towards 0.6 M HCl and 0.2 m NaOH-induced GMand IM injury as compared to CBS. SBS and CBS providedsimilar protection towards 80% ethanol-induced gastric injury, while CBS exerted a superior protectiveability towards aspirin-induced gastric injury. Theresults demonstrate that both SBS and CBS can scavengereactive oxygen species and prevent tissue damage produced by OFR.  相似文献   
3.
Eye infections caused by adenovirus (Ad) often result in nosocomial infections and community epidemics with significant rates of morbidity. No antiviral agent effective against Ad is yet available for clinical use. Therefore, early diagnosis is still the mainstay for patient management and the prevention of epidemics. A multiplex PCR assay based on amplification of a combination of the fiber and hexon genes which can identify the six important oculopathogenic serotypes of Ads (Ad serotype 3[Ad3], Ad4, Ad7, Ad8, Ad19, and Ad37) in a single-tube amplification reaction was developed. Ad serotypes could be distinguished by the different amplicon sizes. The assay correctly identified prototype strains as well as isolates in clinical specimens. In comparison with a previously described PCR-restriction fragment polymorphism method, our assay gave unequivocal results for clinical specimens. Our multiplex PCR has the potential to serve as a rapid and cost-effective tool for the typing of important ocular Ads.  相似文献   
4.
AIMS: To characterise a novel strain (M86) of adenovirus (Ad) involved in epidemic keratoconjunctivitis (EKC). METHODS/RESULTS: The virus strain was neutralised by antisera to both Ad35 and Ad11. Restriction endonuclease analysis of genomic DNA showed 98% and 88% homology with Ad11 and Ad35, respectively. The deduced amino acid sequence of the hypervariable regions of (HVRs) of the hexon gene showed a higher homology with Ad35 (94.4%) than with Ad11 (83.7%). However, it was 100% homologous to Ad35 in HVRs 1, 2, 3, and 6 and to Ad11 in HVRs 4 and 6. In the fibre knob, the isolate was more homologous to Ad11 (99.4%) than to Ad35 (29.1%). CONCLUSION: This novel strain of adenovirus showed similarities with both Ad11 and Ad35. The isolation of a novel strain like Ad35+11 is important because of its association with EKC.  相似文献   
5.
AIMS: To characterise a novel strain of adenovirus (Ad) type Ad8 (genome type Ad8I) involved in an epidemic keratoconjunctivitis (EKC) outbreak in Hiroshima city using serological testing and sequence analysis of the fibre and hexon gene. METHODS: A neutralisation test (NT) was performed in microtitre plates containing a confluent monolayer of A549 cells using 100 tissue culture infectious doses of virus and type specific antisera. The haemagglutination inhibition test was also carried out in microtitre plates with rat erythrocytes using four haemagglutination units of virus and twofold dilutions of serum. The fibre gene was sequenced by generating overlapping polymerase chain reaction products or by direct sequencing of genomic DNA. Primer selection was based on alignment of the fibre genes of human adenovirus serotypes Ad8, Ad19, Ad37, Ad9, and Ad15 available from Gene Bank. RESULTS: The virus strain was specifically neutralised by anti-Ad8 antibodies, although there was a major crossreaction with anti-Ad9 antibodies. Haemagglutination was equally inhibited by anti-Ad8 and anti-Ad9 antibodies. The predicted amino acid sequences of the hypervariable regions (HVRs) of the Ad8I hexon gene showed higher homology with Ad9 (83.3%) than with Ad8 (62.0%). However, the Ad8I fibre knob was more homologous to Ad8 (94.4%) than to Ad9 (91.6%). CONCLUSIONS: Ad8I is a unique strain of adenovirus because of its lower genomic homology with Ad8, major crossreactivity with Ad9 in NT, and mixed genetic organisation of HVRs of the hexon gene. These factors may have enabled the virus to circumvent acquired immunity, resulting in the outbreak.  相似文献   
6.
Nociceptors are excited or sensitized by many inflammatory mediators as well as by elevation of tissue temperature. We have shown that there is a facilitatory synergistic interaction between norepinephrine (NE) and bradykinin (BK) on cutaneous C-fiber nociceptors in normal Lewis rats. These interactions may play an important role in the mechanism of sympathetically maintained pain. In the present experiment, using skin-saphenous nerve in vitro preparations, we tested the effect of NE on the activity of nociceptive fibers and their response to heat in normal Sprague-Dawley rats. For comparison with the previous data on Lewis rats, we also examined the effect of NE on BK response. NE (10(-5) or 10(-6) M) did not excite nociceptive fibers before repeated heat stimuli or BK superfusion (10(-5) or 10(-6) M) to the receptive field. In contrast, after a few applications of heat or BK, NE excited 20-43% of nociceptive fibers to similar magnitudes. We also found that NE sensitized subsequent BK responses, but somewhat unexpectedly that it suppressed subsequent heat responses. This occurred regardless of the presence or absence of NE-induced excitation. These results suggest different mechanisms of NE modification to the BK and heat responses of cutaneous C-fiber nociceptors.  相似文献   
7.
We investigated whether there are any differences between the Lewis and Sprague-Dawley (SD) rats in chronic inflammation-induced norepinephrine (NE) sensitivity of nociceptors. Activities of C-fiber nociceptors innervating rat hairy hindpaw skin were recorded in an in vitro skin-nerve preparation. Sixty-five percent of C-fibers from inflamed Lewis rats were excited by NE (10 microM), against only 38% of C-fibers from inflamed SD rats. The average of the total impulses evoked in response to NE was also significantly higher in Lewis rats. The alpha2-adrenoceptor antagonist CH 38083 (10 microM) and yohimbine (10 microM) consistently blocked the NE-excitation of both strains. These results show that after chronic inflammation, C-fiber nociceptors of Lewis strain rats have a stronger sensitivity to NE, and that alpha2-adrenoceptors are predominately involved in the NE-sensitivity of inflamed rats in both strains.  相似文献   
8.
9.
Obesity is a global public health problem, with about 315 million people worldwide estimated to fall into the WHO-defined obesity categories. Traditional herbal medicines may have some potential in managing obesity. Botanical dietary supplements often contain complex mixtures of phytochemicals that have additive or synergistic interactions. The dried fruit rind of Garcinia cambogia, also known as Malabar tamarind, is a unique source of (-)-hydroxycitric acid (HCA), which exhibits a distinct sour taste and has been safely used for centuries in Southeastern Asia to make meals more filling. Recently it has been demonstrated that HCA-SX or Super Citrimax, a novel derivative of HCA, is safe when taken orally and that HCA-SX is bioavailable in the human plasma as studied by GC-MS. Although HCA-SX has been observed to be conditionally effective in weight management in experimental animals as well as in humans, its mechanism of action remains to be understood. We sought to determine the effects of low-dose oral HCA-SX on the body weight and abdominal fat gene expression profile of Sprague-Dawley rats. We observed that at doses relevant for human consumption dietary HCA-SX significantly contained body weight growth. This response was associated with lowered abdominal fat leptin expression while plasma leptin levels remained unaffected. Repeated high-density microarray analysis of 9960 genes and ESTs present in the fat tissue identified a small set (approximately 1% of all genes screened) of specific genes sensitive to dietary HCA-SX. Other genes, including vital genes transcribing for mitochondrial/nuclear proteins and which are necessary for fundamental support of the tissue, were not affected by HCA-SX. Under the current experimental conditions, HCA-SX proved to be effective in restricting body weight gain in adult rats. Functional characterization of HCA-SX-sensitive genes revealed that upregulation of genes encoding serotonin receptors represent a distinct effect of dietary HCA-SX supplementation.  相似文献   
10.

Objectives

There are two alternative hypotheses regarding bidirectional associations between self-efficacy and planning in predicting health behaviour change: self-efficacy may establish planning (cultivation hypothesis) or planning may enable the formation of self-efficacy (enabling hypothesis). This study investigates the order in which these two social cognitions are linked in adult–adult dyads in the context of sedentary behaviours (SB).

Design

A longitudinal study with 4 measurement points, spanning 8 months.

Methods

A total of 320 dyads (age: 18–90 years) were enrolled. Dyads included a focus person (who received the recommendation to reduce SB and intended to change their SB), and their partners, who were willing to support the focus persons and intended to reduce their own SB as well. Data were collected at Time 1 (T1), Time 2 (1 week later, T2), Time 3 (T3, 2 months after T1) and Time 4 (T4, 8 months after T1). SB was measured with accelerometers at (T1 and T4). Mediation models with individual and dyadic reciprocal effects were tested with path analyses.

Results

Only one indirect effect was found: A higher level of partners' SB reduction-specific self-efficacy at T2 was related to the focus person's more frequent planning to reduce SB at T3, which, in turn, predicted lower SB time among partners at T4.

Conclusions

The findings provide partial support for the cultivation model (self-efficacy prompting planning) and for dyadic reciprocal associations in the context of SB time reduction among adult dyads.  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