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   867篇
  免费   50篇
  国内免费   2篇
耳鼻咽喉   7篇
儿科学   33篇
妇产科学   31篇
基础医学   74篇
口腔科学   25篇
临床医学   72篇
内科学   213篇
皮肤病学   17篇
神经病学   55篇
特种医学   7篇
外科学   115篇
综合类   25篇
预防医学   50篇
眼科学   43篇
药学   106篇
中国医学   5篇
肿瘤学   41篇
  2023年   4篇
  2022年   10篇
  2021年   29篇
  2020年   17篇
  2019年   33篇
  2018年   28篇
  2017年   25篇
  2016年   24篇
  2015年   34篇
  2014年   34篇
  2013年   37篇
  2012年   59篇
  2011年   66篇
  2010年   39篇
  2009年   41篇
  2008年   51篇
  2007年   82篇
  2006年   51篇
  2005年   36篇
  2004年   28篇
  2003年   31篇
  2002年   21篇
  2001年   23篇
  2000年   4篇
  1999年   13篇
  1998年   5篇
  1997年   5篇
  1996年   6篇
  1995年   3篇
  1992年   3篇
  1991年   2篇
  1990年   3篇
  1989年   6篇
  1988年   6篇
  1987年   9篇
  1986年   2篇
  1985年   6篇
  1984年   8篇
  1983年   5篇
  1982年   3篇
  1981年   3篇
  1980年   2篇
  1977年   5篇
  1976年   5篇
  1974年   1篇
  1973年   1篇
  1972年   3篇
  1971年   1篇
  1969年   1篇
  1920年   1篇
排序方式: 共有919条查询结果,搜索用时 15 毫秒
1.
OBJECTIVES: We analyzed the methods and outcomes of urethroplasty in men with complex urethral disruptions. METHODS: The medical records of 40 men with complex urethral disruptions were analyzed. Surgical methods were individualized according to stricture location, severity and length of the stricture, bladder neck characteristics and presence of complicating factors. Patients were divided into four groups based on the above characteristics. RESULTS: End-to-end urethroplasty performed in six patients with short bulbar strictures (<3 cm) was successful in all. Elaborated perineal repair was performed in 10 patients with intermediate (3-6 cm) strictures with or without complicating factors. Elaborated perineal repair with urethral substitution was performed in nine patients with long segment stricture (>6 cm). Abdominal transpubic repair was successfully applied to patients with rectourethral fistula or lacerated bladder neck. Success rate of anastomotic urethroplasty was 95% while over all success rate was 85%. CONCLUSION: Guidelines for urethral reconstruction of complex urethral disruptions are predicated on stricture length, location, bladder neck characteristics and associated complicating factors. End-to-end urethroplasty with stricture excision is highly reliable for short strictures for which previous operative repair have failed. Elaborated perineal repair is extremely versatile for intermediate and longer strictures with associated complicating factors. Abdominal transpubic urethroplasty is effective for patients with rectourethral fistula or lacerated bladder neck.  相似文献   
2.
A file review of 178 male patients with sexual dysfunction revealed that high income, married status, presence of partner at evaluation, and liberal attitude towards sexuality increased the chances of selection for behavioral sex therapy. The outcome of therapy was associated with treatment adherence. Participation of the conjoint unit resulted in lower dropout rates.  相似文献   
3.
Introduction: Visceral Leishmaniasis (VL) re-emerged in the Indian subcontinent in the mid-1970s after an almost complete absence in the previous fifteen or so years. The disease was first noted in Nepal in 1978 and, since 1980, it has been reported regularly in increasing numbers. Elimination of visceral leishmaniasis by 2015 has been identified as regional priority program in the level of high political commitment. Objective: The objectives of this study are the comprehensive assessment of information related to VL on the basis of past research studies conducted in Nepal, and an assessment of the prospects of control measures. Materials and methods: This was time line comprehensive VL epidemiological assessment study based on the research conducted by main author during the past ten years. During the period the studies were conducted using cross sectional, case control and exploratory study design. The statistical analysis was done using qualitative and quantitative methods. Results: In our study in the visceral leishmaniasis endemic district, Siraha, in the population of 112,029, a total of 996 clinically suspected cases were reported (with fever of long duration and splenomegaly, with no malaria) during 1998-2002. In all, 283 subjects were found positive for visceral leishmaniasis by rK39 and 284 had positive bone marrow. There was no detectable difference in the density of Phlebotomus argentipes between high, and moderate incidence village development committees (VDC: the smallest administrative unit), but collections in the low incidence areas (in winter) were negative. P. argentipes was never numerous (maximum 4.4 females collected per man-hour), and was much less common than P. papatasi. Peaks of abundance were recorded in the March and September collections. We have found that the numbers of reported cases of visceral leishmaniasis in Nepalese villages was unaffected by indoor residual spray (IRS) indicated by parallel trends in case numbers by time series analysis in treated and untreated villages. A series of maps through ten years clearly showed that the infection can move rapidly between villages, and it is impossible to predict where transmission will occur from year to year. Conclusion: If maximum benefit in relation to cost is the goal, it may be preferable to put all possible efforts into active case detection (ACD) with free treatment. ACD should involve the network of Village Health Workers or Female Community Health Volunteers and the rK39 dipstick test at health centre level. Surveillance of disease and vector, communication for behavioural impacts and insecticide spraying should be important component of elimination program. If IRS is to be a part of the intervention, it is essential that it is carried out effectively, both in areas where the disease has been reported and in neighbouring areas. Integrated vector management need to be monitored for its application and effectiveness for VL elimination.  相似文献   
4.
5.
By using current biological understanding, a conceptually simple, but mathematically complex, model is proposed for the dynamics of the gene circuit responsible for regulating nitrogen catabolite repression (NCR) in yeast. A variety of mathematical "structure" theorems are described that allow one to determine the asymptotic dynamics of complicated systems under very weak hypotheses. It is shown that these theorems apply to several subcircuits of the full NCR circuit, most importantly to the URE2-GLN3 subcircuit that is independent of the other constituents but governs the switching behavior of the full NCR circuit under changes in nitrogen source. Under hypotheses that are fully consistent with biological data, it is proven that the dynamics of this subcircuit is simple periodic behavior in synchrony with the cell cycle. Although the current mathematical structure theorems do not apply to the full NCR circuit, extensive simulations suggest that the dynamics is constrained in much the same way as that of the URE2-GLN3 subcircuit. This finding leads to the proposal that mathematicians study genetic circuits to find new geometries for which structure theorems may exist.  相似文献   
6.
Beyond deworming     
  相似文献   
7.
Cypermethrin, a class II pyrethroid pesticide, is used to control insects in the household and agricultural fields. Despite beneficial roles, its uncontrolled and repetitive applications lead to unintended effects in non-target organisms. Cypermethrin crosses the blood-brain barrier and induces neurotoxicity and motor deficits. Cypermethrin prolongs the opening of sodium channel, a major site of its action, leading to hyper-excitation of the central nervous system. In addition to sodium channel, cypermethrin modulates chloride, voltage-gated calcium and potassium channels, alters the activity of glutamate and acetylcholine receptors and adenosine triphosphatases and induces DNA damage and oxidative stress in the neuronal cells. Cypermethrin also modulates the level of neurotransmitters, including gamma-aminobutyric acid and dopamine. It is one of the most commonly used pesticides in neurotoxicology research not only because of its variable responses depending upon the doses, time and routes of exposure and strain, age, gender and species of animals used across multiple studies but also owing to its ability to induce the nigrostriatal dopaminergic neurodegeneration. This article describes the effect of acute, chronic, developmental and adulthood exposures to cypermethrin in experimental animals. The article sheds light on cypermethrin-induced changes in the central nervous system, including its contribution in the onset of specific features, which are associated with the nigrostriatal dopaminergic neurodegeneration. Resemblances and dissimilarities of cypermethrin-induced nigrostriatal dopaminergic neurodegeneration with sporadic and chemicals-induced disease models along with its advantages and pitfalls are also discussed.  相似文献   
8.

Background and Objective  

The role of Mycobacterium avium ss paratuberculosis (MAP) in the etiopathology of Crohn’s disease (CD) remains controversial, because of conflicting reports demonstrating the presence of MAP-specific insertion sequence from intestinal biopsy tissues of patients clinically diagnosed for the disease. The present study was carried out to investigate the presence of MAP DNA in the intestinal tissues of CD patients to ascertain the relevance of MAP in Indian patients with CD.  相似文献   
9.

Background  

The decision to preserve the pulmonary valve during intracardiac repair of Tetralogy of Fallot [TOF] is traditionally based on the intra-operative measurement of pulmonary annulus by a Hegar dilator as per Rowlatt’s table. We sought to evaluate if there can be flexibility in not using a transannular patch repair in Indian population with mildly hypoplastic pulmonary annulus.  相似文献   
10.
Sericin, a protein waste product of the silk industry, was crosslinked with chitosan, and a chitosan–sericin conjugate (CS) was prepared, characterized and used to remove hexavalent chromium (Cr(vi)) ions and methyl orange (MO) dye from aqueous solutions. The CS was shown to effectively remove Cr(vi) ions and MO dye at maximum adsorption capacities (Langmuir) of 139 mg g−1 for Cr(vi) ions and 385 mg g−1 for MO dye. Moreover, the adsorption of both Cr(vi) ions and MO dye was highly pH dependent and varied under different experimental conditions. Cr(vi) ion and MO dye uptake by the CS was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy (XPS) and energy dispersive spectrometry analysis. Additionally, XPS analysis of the Cr(vi)-loaded CS revealed that Cr(vi) was reduced to the less toxic Cr(iii). The CS was shown not only to be highly amenable to regeneration, but also to be able to effectively remove MO dye and Cr(vi) ions from a binary mixture.

Sericin, a protein waste product of the silk industry, was crosslinked with chitosan, and a chitosan–sericin conjugate (CS) was prepared, characterized and used to remove hexavalent chromium (Cr(vi)) ions and methyl orange dye from aqueous solutions.  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