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   9079篇
  免费   564篇
  国内免费   69篇
耳鼻咽喉   39篇
儿科学   203篇
妇产科学   84篇
基础医学   978篇
口腔科学   136篇
临床医学   984篇
内科学   2092篇
皮肤病学   151篇
神经病学   518篇
特种医学   226篇
外国民族医学   1篇
外科学   1804篇
综合类   223篇
现状与发展   2篇
一般理论   5篇
预防医学   590篇
眼科学   171篇
药学   856篇
中国医学   172篇
肿瘤学   477篇
  2024年   15篇
  2023年   146篇
  2022年   409篇
  2021年   687篇
  2020年   407篇
  2019年   511篇
  2018年   506篇
  2017年   305篇
  2016年   333篇
  2015年   369篇
  2014年   440篇
  2013年   522篇
  2012年   813篇
  2011年   729篇
  2010年   356篇
  2009年   342篇
  2008年   516篇
  2007年   490篇
  2006年   402篇
  2005年   347篇
  2004年   293篇
  2003年   274篇
  2002年   150篇
  2001年   50篇
  2000年   40篇
  1999年   29篇
  1998年   31篇
  1997年   15篇
  1996年   13篇
  1995年   9篇
  1994年   10篇
  1993年   17篇
  1992年   8篇
  1991年   10篇
  1990年   8篇
  1989年   9篇
  1988年   7篇
  1987年   5篇
  1985年   7篇
  1984年   9篇
  1983年   5篇
  1982年   7篇
  1981年   15篇
  1980年   7篇
  1978年   5篇
  1977年   4篇
  1976年   4篇
  1974年   5篇
  1973年   3篇
  1972年   3篇
排序方式: 共有9712条查询结果,搜索用时 187 毫秒
11.
Arsenic (As) and cadmium (Cd) have recently emerged as major health concerns owing to their strong association with diabetes mellitus (DM). We aimed to investigate the heavy metals exposure towards incidence of DM at various enzymatic and hormonal levels. Additionally, association of As and Cd with Zinc (Zn, essential metal) was also evaluated. Spot urine samples were collected to assess As, Cd and Zn through ICP-OES. Serum was analyzed by assay method for fasting blood glucose, liver and renal function biomarkers. ELISA was performed to investigate the impact of heavy metals on HbA1c, α-amylase, DPP-IV, IGF-1, leptin, GSH, MDA, SOD, HDL, FFA, TG and interleukin (IL)-6. Association of heavy metals with DM was measured by odds ratio (OR) and level of significance was assessed by Chi-squared test. Unpaired student's t-test was used to compare DM-associated risk factors in heavy metals-exposed and unexposed participants. As and Cd were detectable in 75.4% and 83% participants with mean concentration of 75.5 ppb and 54.5 ppb, respectively. For As exposure, OR in the third quartile was maximum ie 1.34 (95% CI, 0.80 to 2.23), however the result was not statistically significant (P > .05). For Cd exposure, OR in the fourth quartile was considerably high, 1.62 (95% CI, 1.00 to 2.61), with a significant probability value (P < .05). Urinary Cd was negatively associated with Zn. As and Cd exposure increases the incidence of DM in the general population. Impaired hormonal and enzymatic levels in diabetic and non-diabetic exposed participants reflect the multiple organ damage by heavy metal exposure.  相似文献   
12.
ObjectivesSevere acute kidney injury (AKI) is a known risk factor for infection and mortality. However, whether stage 1 AKI is a risk factor for infection has not been evaluated in adults. We hypothesized that stage 1 AKI following cardiac surgery would independently associate with infection and mortality.MethodsIn this retrospective propensity score–matched study, we evaluated 1620 adult patients who underwent nonemergent cardiac surgery at the University of Colorado Hospital from 2011 to 2017. Patients who developed stage 1 AKI by Kidney Disease Improving Global Outcomes creatinine criteria within 72 hours of surgery were matched to patients who did not develop AKI. The primary outcome was an infection, defined as a new surgical-site infection, positive blood or urine culture, or development of pneumonia. Secondary outcomes included in-hospital mortality, stroke, and intensive care unit (ICU) and hospital length of stay (LOS).ResultsStage 1 AKI occurred in 293 patients (18.3%). Infection occurred in 20.9% of patients with stage 1 AKI compared with 8.1% in the no-AKI group (P < .001). In propensity-score matched analysis, stage 1 AKI independently associated with increased infection (odds ratio [OR]; 2.24, 95% confidence interval [CI], 1.37-3.17), ICU LOS (OR, 2.38; 95% CI, 1.71–3.31), and hospital LOS (OR, 1.30; 95% CI, 1.17-1.45).ConclusionsStage 1 AKI is independently associated with postoperative infection, ICU LOS, and hospital LOS. Treatment strategies focused on prevention, early recognition, and optimal medical management of AKI may decrease significant postoperative morbidity.  相似文献   
13.
I Muhammad  O Mabogunje 《Injury》1990,21(3):174-176
The records of 37 patients with liver injuries operated upon at the Ahmadu Bello University Teaching Hospital, Zaria, Nigeria from 1976 to 1987 were reviewed. There were 31 males and 6 females with a mean age of 22 years. Sixty-two per cent were due to blunt injury from road traffic accidents, 14 per cent were due to gunshot wounds and 5 per cent due to stab wounds as a result of assaults. Treatment with simple suture and drainage sufficed in 49 per cent; only 16 per cent required resection, packing and drainage. Associated injuries included long bone fractures and chest trauma. The most common complication was sepsis and the overall mortality was 19 per cent.  相似文献   
14.
BACKGROUND: A subgroup of children with obsessive-compulsive and tic disorders are proposed to have an infectious trigger. The purpose of this study was to investigate the relationship between group A streptococcal titers and symptom fluctuations in children with a clinical course resembling that described for pediatric autoimmune neuropsychiatric disorders associated with streptococcus. METHODS: Twenty-five children with obsessive-compulsive disorder and/or tic disorder were evaluated for neuropsychiatric severity and group A streptococcal antibody titers (streptolysin O, deoxyribonuclease B, and carbohydrate A) at 6-week intervals for > or = six consecutive evaluations (total visits=277). RESULTS: Children with large symptom fluctuations (n=15) were compared with children without dramatic fluctuations (n=10). Co-movements of obsessive-compulsive/tic severity and group A streptococcal antibodies were assessed. In subjects with large symptom changes, positive correlations were found between streptococcal titers and obsessive-compulsive severity rating changes (p=.0130). These subjects were also more likely to have elevated group A streptococcal titers during the majority of observations (p=.001). Tic symptom exacerbations occurred more often in the fall/winter months than spring/summer months (p=.03). CONCLUSIONS: Patients with marked obsessive-compulsive/tic symptom changes may be characterized by streptococcal titer elevations and exhibit evidence of seasonal tic exacerbations.  相似文献   
15.
16.
Dimethyl sulfoxide(DMSO) is frequently used as a solvent for antifungal drugs in various studies to determine their MICs. Reports on comparative evaluation of methods for the susceptibility testing of antifungal drugs have shown there is poor agreement among methods. Besides other factors which could cause variability in the results, one important factor might be the effect of DMSO on the growth of fungi. The effect of DMSO on the growth of some species of Candida has been reported in the literature. The present study aimed at determination of the effect of different concentrations of DMSO (0.125 to 10%) on the growth of dermatophytes by agar diffusion method. There was no growth of fungi in 10% DMSO, between 1.25 and 5% there was a rather linear dose-related inhibitory effect on the growth, significantly different from the controls, and below 1% there was a variable effect among the species. DMSO down to 0.25% significantly inhibited the growth of most strains of M. canis. The lower concentrations of DMSO, which apparently do not affect the growth of fungi, may potentiate the effect of antifungal drugs.  相似文献   
17.
18.
Gangliosides of cultured astroglia   总被引:3,自引:0,他引:3  
Cultured astrocytes prepared from newborn rat brain and 13-day-old chick embryonic brain were analyzed qualitatively and quantitatively for ganglioside content. All preparations contained approximately the same total level: 2.4-3.4 micrograms N-acetylneuraminic acid (NeuAc)/mg protein. In contrast, the value for primary cultures of neurons from chick embryonic brain was 5.9. The non-hexosamine-containing species, GM3 and GD3, comprised 75-85% of the total in astroglial cultures, the remainder consisting mainly of structural types other than the gangliotetraose series; choleragenoid assay revealed the latter to be virtually absent or to comprise at most a few percent. Deficiency of gangliotetraose synthesizing ability was indicated by the very low level of UDP-GalNac:GM3 N-acetylgalactosaminyltransferase detected in the cells. Treatment of cultured astrocytes with astroglial growth factor 2 or dibutyryl cyclic AMP caused little if any change in quantity or pattern of gangliosides. The large majority of cells stained in a manner characteristic of astrocytes: positive for glial fibrillary acidic protein, negative for galactosyl ceramides. Staining with cholera toxin and anti-GM1 antibody was essentially negative, as was that with tetanus toxin, A2B5 monoclonal antibody, and antibody to GD3. All evidence thus points to cultured astrocytes of rat and chick brain containing appreciable gangliosides, most of which are GM3 and GD3 with the majority of the remainder comprising structures other than the gangliotetraose type.  相似文献   
19.
Data are limited on seizure recurrence after antiepileptic drug (AED) discontinuation in operated seizure-free patients. We reviewed seizure outcome in patients who came off AEDs after being seizure-free for 2 years following temporal lobe surgery in our center. Thirty-nine (68%) of 57 patients who discontinued AED therapy remained seizure-free. They had a younger age at surgery than the group with seizure recurrence (p=0.01). Earlier surgery may be a favorable predictor for seizure freedom after AED discontinuation.  相似文献   
20.
Modification of the current allocation system for donor livers in the United States to incorporate recipient serum sodium concentration ([Na]) has recently been proposed. However, the impact of this parameter on posttransplantation mortality has not been previously examined in a large risk-adjusted analysis. We assessed the effect of recipient [Na] on the survival of all adults with chronic liver disease who received a first single organ liver transplant in the UK and Ireland during the period March 1, 1994 to March 31, 2005 (n=5,152) at 3 years, during the first 90 days, and beyond the first 90 days, adjusting for a wide range of recipient, donor, and graft characteristics. Compared to those with normal [Na] (135-145 meq/L; n=3,066), severely hyponatremic recipients ([Na]<130 meq/L, n=541), had a higher risk-adjusted mortality at 3 years (hazard ratio [HR] 1.28; 95% confidence interval [CI], 1.04-1.59; P<0.02). The excess mortality was, however, confined to the first 90 days (HR 1.55; 95% CI, 1.18-2.04; P<0.002) with no significant difference thereafter. This was also true for hypernatremic recipients ([Na]>45 meq/L, n=81), who had an even greater risk-adjusted mortality compared to normonatremic recipients (overall: HR 1.85; 95% CI, 1.25-2.73; P<0.002; 90 days: HR 1.12; 95% CI, 0.55-2.29; P=0.8), whereas mildly hyponatremic recipients ([Na] 130-134 meq/L, n=1,127) had similar risk-adjusted mortality to those with normal [Na] at the same time points. In conclusion, recipient [Na] is an independent predictor of death following liver transplantation. Attempts to correct the [Na] toward the normal reference range are an important aspect of pretransplantation management.  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