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   1633篇
  免费   126篇
  国内免费   11篇
耳鼻咽喉   24篇
儿科学   36篇
妇产科学   30篇
基础医学   242篇
口腔科学   21篇
临床医学   177篇
内科学   407篇
皮肤病学   64篇
神经病学   102篇
特种医学   44篇
外科学   157篇
综合类   39篇
预防医学   145篇
眼科学   37篇
药学   124篇
中国医学   7篇
肿瘤学   114篇
  2023年   24篇
  2022年   37篇
  2021年   52篇
  2020年   32篇
  2019年   51篇
  2018年   63篇
  2017年   55篇
  2016年   54篇
  2015年   76篇
  2014年   79篇
  2013年   93篇
  2012年   156篇
  2011年   128篇
  2010年   78篇
  2009年   57篇
  2008年   96篇
  2007年   88篇
  2006年   82篇
  2005年   83篇
  2004年   74篇
  2003年   60篇
  2002年   56篇
  2001年   29篇
  2000年   27篇
  1999年   13篇
  1998年   7篇
  1997年   9篇
  1996年   6篇
  1995年   6篇
  1994年   4篇
  1993年   3篇
  1992年   8篇
  1991年   8篇
  1990年   10篇
  1989年   13篇
  1988年   8篇
  1987年   4篇
  1986年   2篇
  1985年   3篇
  1984年   11篇
  1983年   6篇
  1980年   1篇
  1979年   4篇
  1978年   1篇
  1977年   2篇
  1976年   1篇
  1970年   3篇
  1965年   2篇
  1957年   1篇
  1941年   1篇
排序方式: 共有1770条查询结果,搜索用时 15 毫秒
121.
122.
自膨式金属内支架在恶性食管梗阻中的临床应用   总被引:6,自引:0,他引:6  
目的:评价自膨式金属内支架(SEMS)治疗恶性食管梗阻的疗效。方法:38例恶性食管狭窄患者在荧光屏监视下置入42枚支架,包括带膜支架和裸露支架,国产支架和进口支架。结果:42例支架均一次性置入成功,技术成功率100%。术后患者吞咽困难及生活质量明显改善,未发生严重的并发症。结论:自膨式金属内支架缓解食管梗阻简单、快速、安全、有效。  相似文献   
123.
The establishment of a tracheal airway with direct laryngoscopy can either be difficult or impossible in children with airway pathology. Multiple direct laryngoscopic attempts cause oedema and/or bleeding with subsequent difficult ventilation. The techniques utilizing the laryngeal mask airway (LMATM) and the fibreoptic bronchoscope have been reported. The case of a child with lingual thyroglossal duct cyst in which the LMA was useful to secure the airway and as a conduit for fibreoptic tracheal intubation is reported.  相似文献   
124.
Su W  Sin M  Darrow A  Sherman LS 《Glia》2003,42(4):350-358
Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive malignancies that arise within peripheral nerves. These tumors occur with increased incidence in patients with neurofibromatosis type 1 (NF1), exhibiting increased Ras activity due to loss of the NF1 gene product, neurofibromin, and abnormal expression of the epidermal growth factor receptor (EGFR). We previously found that MPNSTs express increased levels of the CD44 family of transmembrane glycoproteins that have been implicated in tumor cell invasion and metastasis. In two MPNST cell lines, we have found that elevated CD44 expression and cell invasion are dependent on Src kinase activity but are independent of mitogen-activated protein kinases (MAPK) kinase (MEK) activity. In contrast, inhibition of Src kinase activity has no influence on MPNST cell proliferation. Reduction of CD44 levels, using antisense oligonucleotides, results in reduced MPNST cell invasion in vitro, suggesting that Src contributes in part to MPNST cell invasion by increasing CD44 levels. At least some of this increased CD44 expression results from elevated EGFR levels through a Src-dependent mechanism, consistent with the notion that EGFR promotes constitutive Src activation in MPNSTs. These data indicate that Src and CD44 are putative targets for the treatment of MPNST invasion and metastasis.  相似文献   
125.
There is growing evidence of the benefits of family and carers interventions using a psycho-educational model for carers of people with psychosis. In order to get this work into clinical practice, a network of interrelated services for carers and families of people with psychoses has been established in Reading, Berkshire. This paper reports the experience of the authors in establishing these services using a series of practice development initiatives including training for staff, education programmes, integration projects and collaboration across organizations. This work illustrates change processes through which evidence-based practice has been incorporated into routine clinical care and in which research-based assessment and evaluation tools have being used in routine clinical practice to measure outcomes.  相似文献   
126.
There is considerable controversy concerning the utility of inhaled corticosteroids for the long-term treatment of patients with COPD. Recent studies have suggested that although inhaled corticosteroids do not alter the rate of decline in lung function, they may reduce airway hyperresponsiveness, decrease the frequency of exacerbations, and slow the rate of decline in the patients' health status. The relationship between inhaled corticosteroids and subsequent risk of hospitalization or mortality remains unknown. We therefore conducted a population-based cohort study using administrative databases in Ontario, Canada (n = 22,620) to determine the association between inhaled corticosteroid therapy and the combined risk of repeat hospitalization and all-cause mortality in elderly patients with COPD. Patients who received inhaled corticosteroid therapy postdischarge (within 90 d) had 24% fewer repeat hospitalizations for COPD (95% confidence interval [CI], 22 to 35%) and were 29% less likely to experience mortality (95% CI, 22 to 35%) during 1 yr of follow-up after adjustment for various confounding factors. This cohort study has suggested that inhaled corticosteroid therapy is associated with reduced COPD-related morbidity and mortality in elderly patients. Although not definitive, because of the observational nature of these findings, these data provide a compelling rationale for a large randomized trial to determine the effect of inhaled corticosteroids on COPD-related morbidity and mortality.  相似文献   
127.
1. The effect of different doses of ouabain, an inhibitor of the sodium pump, or saline (9 g sodium chloride/1; the vehicle) on the metabolic rate of guinea-pigs weighing 500 g was measured by indirect calorimetry for 120 min. 2. Ouabain (0.02-0.07 nmol/g body-weight) decreased the oxygen consumption in a dose-related manner. When higher doses of ouabain (0.10 nmol/g body-weight or greater) were injected the animals were observed to shiver. Ouabain (0.07 nmol/g body-weight) reduced Na+,K+-ATPase (EC 3.6.1.3) activity of liver, kidney and skeletal muscle by 18.0 (SE 6.6), 21.5 (SE 6.0) and 21.9 (SE 6.8)% respectively. An Eadie-Hofstee plot of percentage decrease in O2 consumption v. percentage inhibition divided by dose of ouabain showed that maximal inhibition of O2 consumption was 39.4%. 3. It is concluded that Na pump activity contributed to about 40% of the resting O2 consumption.  相似文献   
128.

BACKGROUND:

Psychosocial stress can be the cause or the consequence of hypertension.

OBJECTIVE:

To study the association between hypertension and anxiety or depression in adults from Hong Kong, China.

SUBJECTS AND METHODS:

Patients with diagnosed hypertension (n=197) were recruited to complete the Hospital Anxiety and Depression Scale (HADS) questionnaire. The control group comprised 182 normotensive subjects recruited using random telephone numbers.

RESULTS:

The score in the anxiety subscale (HADS-A) of the HADS correlated with age (r= −0.23, P<0.001) and sex (r=0.11, P=0.042), and was found to be higher in women. The score in the depression subscale (HADS-D) correlated with age (r=0.17, P=0.003) and hypertension (r=0.12, P=0.039), but not with sex (r=0.02, P=0.68). When the control subjects were matched for sex and age with the subjects with hypertension, the mean HADS-A score was 5.51±0.41 in 113 hypertensive subjects and 4.38±0.39 in 113 normotensive subjects (P=0.047). The mean HADS-D score was 5.56±0.39 in the hypertensive and 4.76±0.32 in the normotensive subjects (P=0.11). Multiple regression analysis using data from both groups indicated that the HADS-A score was related to the HADS-D score (β=0.49, P<0.001), age (β= −0.25, P<0.001) and sex (β=0.12, P=0.01) (R2=0.28), whereas the HADS-D score was related to the HADS-A score (β=0.48, P<0.001), age (β=0.30, P<0.001), positive smoking status (β=0.13, P=0.004) and lack of exercise habit (β=0.12, P=0.008) (R2=0.31). Hypertension was related to waist circumference, history of parental hypertension and age (R2=0.38, P<0.001). Anxiety and depression scores were rejected as independent variables.

CONCLUSIONS:

Hypertension was associated with anxiety but not depression; however, age, history of parental hypertension and central obesity appeared to have a stronger association with hypertension in adults from Hong Kong.  相似文献   
129.
This paper presents a statistical model constructed using logisticregression to identify those at high-risk of repeating parasuicide. Thesubjects in the study are Cork city residents who exhibited parasuicidalbehaviour between 1 January and 30 June 1995. Repetition of the behaviourwithin six months of the index episode distinguishes repeaters fromnon-repeaters. The model was designed so that it could be used bynon-clinicians and hence does not require information relating topsychiatric diagnosis or use of psychiatric services. The proportion ofsubjects correctly classified remained stable across a range of cut-pointprobabilities (mean = 86%, range: 83.9–87.5%). Using acut-point of 0.2, 96% of repeaters and 81% of non-repeaters were correctly classified. Using 0.45 led to the correct identification of81% of repeaters and 90% of non-repeaters. If these highlevels of sensitivity and specificity are maintained in validation tests onfuture cohorts in Cork city then the model could form the basis of anintervention programme designed to prevent the repetition of parasuicide.  相似文献   
130.
Dengue virus (DENV) and Zika virus (ZIKV) belong to the Flaviviridae family of viruses spread by Aedes aegypti mosquitoes in tropical and subtropical areas. Accurate diagnostic tests to differentiate the 2 infections are necessary for patient management and disease control. Using characterized ZIKV and DENV patient plasma in a blind manner, we validated an ELISA and a rapid immunochromatographic test for ZIKV detection. We engineered the ZIKV nonstructural protein 1 (NS1) for sensitive serologic detection with low cross reactivity against dengue and developed monoclonal antibodies specific for the ZIKV NS1 antigen. As expected, the serologic assays performed better with convalescent than acute plasma samples; the sensitivity ranged from 71% to 88%, depending on the performance of individual tests (IgM/IgG/NS1). Although serologic tests were generally less sensitive with acute samples, our ZIKV NS1 antibodies were able to complement the serologic tests to achieve greater sensitivity for detecting early infections.  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