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   3134篇
  免费   204篇
  国内免费   37篇
耳鼻咽喉   39篇
儿科学   114篇
妇产科学   145篇
基础医学   307篇
口腔科学   127篇
临床医学   265篇
内科学   525篇
皮肤病学   83篇
神经病学   143篇
特种医学   117篇
外国民族医学   2篇
外科学   588篇
综合类   71篇
一般理论   3篇
预防医学   219篇
眼科学   93篇
药学   325篇
中国医学   21篇
肿瘤学   188篇
  2023年   34篇
  2022年   99篇
  2021年   163篇
  2020年   116篇
  2019年   158篇
  2018年   183篇
  2017年   102篇
  2016年   124篇
  2015年   115篇
  2014年   136篇
  2013年   214篇
  2012年   251篇
  2011年   289篇
  2010年   152篇
  2009年   104篇
  2008年   171篇
  2007年   136篇
  2006年   137篇
  2005年   103篇
  2004年   114篇
  2003年   81篇
  2002年   68篇
  2001年   33篇
  2000年   15篇
  1999年   18篇
  1998年   22篇
  1997年   12篇
  1996年   12篇
  1995年   7篇
  1994年   12篇
  1993年   8篇
  1992年   12篇
  1991年   21篇
  1990年   15篇
  1989年   8篇
  1988年   7篇
  1987年   11篇
  1985年   9篇
  1984年   16篇
  1983年   6篇
  1982年   9篇
  1981年   6篇
  1980年   4篇
  1979年   4篇
  1978年   5篇
  1976年   9篇
  1974年   4篇
  1973年   4篇
  1972年   5篇
  1966年   5篇
排序方式: 共有3375条查询结果,搜索用时 46 毫秒
21.
BACKGROUND CONTEXTCauda equina syndrome (CES) occurs due to compression of the lumbar and sacral nerve roots and is considered a surgical emergency. Although the condition is relatively rare, the associated morbidity can be devastating to patients. While substantial research has been conducted on the timing of treatment, the literature regarding long-term rates of bladder dysfunction in CES patients is scarce.PURPOSEThe aim of this study was to identify long-term rates of bladder dysfunction in CES patients and to compare those rates to non-CES patients who underwent similar spinal decompression.STUDY DESIGN/SETTINGRetrospective database study.PATIENT SAMPLEThe CES cohort was comprised of 2,362 patients who underwent decompression surgery following CES diagnosis with a 5-year follow-up. These patients were matched to 9,448 non-CES control patients who underwent spinal decompression without a diagnosis of CES.OUTCOME MEASURESDiagnosis of bladder dysfunction, surgical procedure to address bladder dysfunctionMETHODSUsing the national insurance claims database, PearlDiver, CES patients who underwent decompression surgery were identified and 1:4 matched to non-CES patients who underwent similar spinal decompression surgery. The 1-year, 3-year, and 5-year rates of progression to a bladder dysfunction diagnosis and surgical intervention to manage bladder dysfunction were recorded. The CES and non-CES groups were compared with univariate testing, and an analysis of risk factors for bladder dysfunction was performed with multivariate logistic regression analysis.RESULTSA total of 2,362 CES patients who underwent decompression surgery were identified and matched to 9,448 non-CES control patients. After 5 years, CES patients had a 10%–12% increased absolute risk of continued bladder dysfunction and a 0.7%–0.9% increased absolute risk of undergoing a surgical procedure for bladder dysfunction, as compared to matched non-CES patients. Multivariate analysis controlling for age, sex, obesity, tobacco use, and diabetes, identified CES as independently associated with increased 5-year risk for bladder dysfunction diagnosis (odds ratio [OR]: 1.72; 95% confidence interaval [CI] 1.56–1.89; p<.001) and procedure (OR: 1.40; 95% CI 1.07–1.81; p=.012).CONCLUSIONSUnderstanding the long-term risk for bladder dysfunction in CES patients is important for the future care and counseling of patients. Compared to non-CES patients who underwent similar spinal decompression, CES patients were observed to have a significantly higher long-term likelihood for both bladder dysfunction diagnosis and urologic surgical procedure.  相似文献   
22.
PurposeSurgical treatment in advanced-stage infantile Blount’s disease with medial plateau (MP) depression is challenging. Several osteotomies and fixation methods have been described with no established benchmark. We conducted this study to evaluate the efficacy and safety of a new single-stage technique for acute medial condyle elevation and metaphyseal osteotomies with internal fixation.MethodsA prospective case series of 19 consecutive patients (21 knees) with severe infantile Blount’s disease underwent a single-stage MP elevation and metaphyseal osteotomies, with internal fixation. The mean age was 10.3 years (8.2 to 13.6) and the mean follow-up was 5.1 years (3.2 to 8.3). The outcome measures included clinical and radiological parameters and patient-reported pediatric outcomes data collection instrument (PODCI) score.ResultsThe mean PODCI score improved significantly from 50% to 88%. The mean internal tibial torsion improved from -27° to 11°. All cases maintained full knee extension, no limitation in flexion range of movement and no signs of instability or lateral thrust gait. All the radiographic parameters improved significantly; the mean tibiofemoral angle improved from -29° to 7°, the metaphyseal-diaphyseal angle improved from 33.4° to 4.7° and the angle of depressed MP improved from 38.3° to 2.4° (p < 0.001). At the latest follow-up, no cases of deformity recurrence were identified, the final limb-length discrepancy was < 1 cm in all patients.ConclusionSingle-stage MP elevation and metaphyseal osteotomies with internal fixation significantly improved the clinical and radiographic parameters and PODCI score in advanced infantile Blount’s disease and precluded the use of external immobilization, with no evidence of deformity recurrence.Level of evidenceIV  相似文献   
23.
BACKGROUND: Melasma is a chronic hypermelanotic disorder that is challenging to treat; no single effective therapeutic agent for it has been discovered. Methimazole, an oral antithyroid drug, has a skin depigmenting effect when used topically. OBJECTIVE: We sought to evaluate the efficacy and safety of methimazole, applied during microneedling sessions and additional topical use in between sessions, for the treatment of melasma. METHODS: This split-face study included 30 Egyptian patients with melasma, each of whom received 12 microneedling sessions once per week for 12 weeks followed by topical methimazole on the right side of face and placebo on the left side. In between the sessions, topical methimazole 5% cream was applied twice per day on the right side and placebo on the left side. Assessments were performed using the Hemi-melasma Area and Severity Index (hemi-MASI) percentage of improvement, patient satisfaction, dermoscopy, and thyroid-stimulating hormone (TSH) serum levels. RESULTS: There were significant clinical and dermoscopic improvements; hemi-MASI scores on the methimazole-treated right sides were decreased (p<0.001). The percent of hemi-MASI score improvement was significantly associated with the malar pattern (p=0.031) and epidermal type (p=0.04) of melasma. About 70 percent of our studied patients reported being satisfied with their treatment response (7% excellent, 33% good, 30% fair). No significant local or systemic side effects were observed. Pre- and posttreatment serum TSH levels were within the normal range in all treated cases. CONCLUSIONS: Methimazole has the potential to be a safe and promising therapeutic agent for the treatment of melasma via dermapen-delivered microneedling sessions with topical use in between sessions.  相似文献   
24.
The aim of this paper is twofold. Firstly, to investigate the potential benefits of online health communities (OHCs) for informal caregivers by conducting a systematic literature review. Secondly, to identify the relationship between the potential benefits of OHCs and resilience factors of older adults. Performing a thematic analysis, we identified the potential benefits of OHCs for informal caregivers of older adults, including two salient themes: (a) caregivers sharing and receiving social support and (b) self and moral empowerment of caregivers. Then, we uncovered how these potential benefits can support resilience of older adults. Our findings show that sharing and receiving of social support by informal caregivers, and self and moral empowerment of informal caregivers in OHCs, can support four resilience factors among older adults, including self-care, independence, altruism and external connections. This review enables a better understanding of OHCs and Gerontology, and our outcomes also challenge the way healthcare and aged-care service providers view caregivers and older adults. Furthermore, the identified gap and opportunities would provide avenues for further research in OHCs.  相似文献   
25.
A convenient method for the preparation of imidazobenzimidazole3, imidazoimidazole5, imidazotriazole6 and pyrano [2, 3-c] oxazole7 derivatives is described. This depends on interaction of 2-methyl-4-arylidene-2-oxazolin-5-ones1 with o-diamines, thiosemicarbazide and/or ethylcyanoacetate. The effect of alcoholic potassium cyanide on oxazolinone1 was studied. Antibacterial activity of the obtained products was studied.  相似文献   
26.
The effect of the antineoplastic immunosuppressive alkylating agent cyclophosphamide (CPhA) on the modification of the carcinogen-metabolizing capacity was studied in vivo in mouse liver microsomes at different durations of treatment, from one to six consecutive days. The in vitro effect of increasing concentrations of the drug upon this enzyme system was also investigated. Following the administration of CPhA, a significant time-dependent decrease was observed in the activity of the low substrate level of the hepatic microsomal N-nitrosodimethylamine demethylase (NDMAdII). The high substrate level of the enzyme (NDMAdII) also exhibited a similar decrease which was not a subject for the treatment intervals where the greatest decrease (-60%; p<0.05) emerged at day 3 of the administration-point. The activity of the aryl hydrocarbon (benzo(alpha)pyrene) hydroxylase (AHH) revealed a significant increase at the single dose of CPhA, while at the repeated dose treatment (for 3 days) no alteration was noticed in the enzyme activity. This figure of expression in AHH was reversed to a significant inhibition at the 6 day-repeated dose, the time-point at which an almost identical effect was also observed in the hepatic content of cytochrome P450. The alterations in the metabolism of NDMA and benzo(alpha)pyrene which had been seen in the in vivo assays was further confirmed by the results of the in vitro experiment.  相似文献   
27.
Sixty-five institutionalized boy delinquents in Alexandria aged 11 to 21 years were screened for intellectual functioning (I.Q. level) in relation to behavioral deviance. Findings revealed that the mean I.Q. score on the intelligence scale was within the average level of intelligence. The presence of behavior disorder varied insignificantly as a function of intellectual level. Results of this study do not indicate the prevalence of behavior disorders in relation to intellectual functioning in the total population of delinquent children not officially declared. However, the results could be a valid index of the demand for mental health services for the delinquent children, in whom "nonintellectual factors" (familial and psychosocial) might have a significant role in shaping their behavior.  相似文献   
28.
Draize rabbit eye test scores, as modified maximum average score (MMAS), for 68 pure bulk liquids were adjusted by the liquid-saturated vapor pressure P. These 68 adjusted scores, as log (MMAS/P), were shown to be completely equivalent to eye irritation thresholds (EIT), expressed as log (1/EIT), for 23 compounds in humans. Thus, for the first time the Draize eye test in rabbits for pure bulk liquids is shown to be perfectly compatible with eye irritation thresholds in humans. The total data set for 91 compounds was analyzed by the general solvation equation of Abraham. Values of log (MMAS/P) or log (1/EIT) could be fitted to a five-parameter equation with R2 = 0.936, SD = 0.433, AD = 0.000, and AAD = 0.340 over a range of 9.6 log units. When divided into a training set of 45 compounds, the corresponding equation could be used to predict the remaining 46 compounds in a test set with AD = -0.037 and AAD = 0.345 log units. Thus, the 91-compound equation can now be used to predict further EIT values to around 0.4 log units. It is suggested that the mechanism of action in the Draize test and in the human EIT involves passive transfer of the compound to a biophase that is quite polar, is a strong hydrogen bond base, a moderate hydrogen bond acid, and quite hydrophobic. The biophase does not resemble water or plasma, but resembles an organic solvent such as N-methylformamide.  相似文献   
29.
30.
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