全文获取类型
收费全文 | 17562篇 |
免费 | 812篇 |
国内免费 | 92篇 |
专业分类
耳鼻咽喉 | 177篇 |
儿科学 | 373篇 |
妇产科学 | 362篇 |
基础医学 | 2016篇 |
口腔科学 | 1456篇 |
临床医学 | 1167篇 |
内科学 | 4581篇 |
皮肤病学 | 434篇 |
神经病学 | 1430篇 |
特种医学 | 301篇 |
外科学 | 2532篇 |
综合类 | 90篇 |
一般理论 | 4篇 |
预防医学 | 1246篇 |
眼科学 | 374篇 |
药学 | 782篇 |
中国医学 | 88篇 |
肿瘤学 | 1053篇 |
出版年
2024年 | 11篇 |
2023年 | 131篇 |
2022年 | 276篇 |
2021年 | 588篇 |
2020年 | 333篇 |
2019年 | 536篇 |
2018年 | 618篇 |
2017年 | 410篇 |
2016年 | 426篇 |
2015年 | 524篇 |
2014年 | 743篇 |
2013年 | 903篇 |
2012年 | 1468篇 |
2011年 | 1588篇 |
2010年 | 900篇 |
2009年 | 735篇 |
2008年 | 1211篇 |
2007年 | 1373篇 |
2006年 | 1161篇 |
2005年 | 1024篇 |
2004年 | 898篇 |
2003年 | 749篇 |
2002年 | 765篇 |
2001年 | 90篇 |
2000年 | 66篇 |
1999年 | 74篇 |
1998年 | 118篇 |
1997年 | 98篇 |
1996年 | 82篇 |
1995年 | 57篇 |
1994年 | 57篇 |
1993年 | 44篇 |
1992年 | 28篇 |
1991年 | 23篇 |
1990年 | 25篇 |
1989年 | 11篇 |
1988年 | 19篇 |
1987年 | 15篇 |
1986年 | 14篇 |
1985年 | 16篇 |
1984年 | 31篇 |
1983年 | 22篇 |
1982年 | 15篇 |
1981年 | 27篇 |
1980年 | 24篇 |
1979年 | 17篇 |
1978年 | 15篇 |
1977年 | 20篇 |
1976年 | 16篇 |
1975年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Francisco Cano Angela Delucchi Eduardo Wolff Eugenio Rodriguez Angel Fuentes 《Pediatric nephrology (Berlin, Germany)》1995,9(5):606-608
A 6-month protocol of oral pulse calcitriol was used in nine uraemic children (2–14 years old) on dialysis who presented with renal osteodystrophy. Calcitriol was administered twice a week, 4 g per dose for patients over 30 kg and 3g for patients less than 30 kg. Plasma levels of parathyroid hormone, calcium, phosphorus and alkaline phosphatase were carefully controlled during the study. Parathyroid hormone levels decreased by 68% and 56% by the 2nd and 6th months of treatment in seven patients, while they remained unchanged in two patients with focal segmental glomerulosclerosis and massive proteinuria. Eight hypercalcaemic episodes from 77 determinations were observed, all of them recovered after 1 week of vitamin D withdrawal. We conclude that oral calcitriol pulse therapy is a good alternative for renal osteodystrophy in uraemic children. Careful monitoring of plasma parathyroid hormone and calcium is needed during follow-up when using this approach in paediatric patients. 相似文献
102.
Riveros EG 《Annals of nuclear medicine》1999,13(5):367-368
Eight patients were inadvertently administered, and imaged with, 99mTc-labeled MDP which was 45 months expired. Two cases are presented. All patients were subsequently imaged with normal MDP. The images obtained with expired MDP were clinically acceptable. No differences in scan abnormalities were observed compared with normal MDP for any of the patients. None of the patients suffered any side effects attributable to the expired MDP. 相似文献
103.
Oliveira EA Diniz JS Cabral AC Leite HV Colosimo EA Oliveira RB Vilasboas AS 《Pediatric nephrology (Berlin, Germany)》1999,13(9):859-864
With the increasing use of obstetric echography fetal hydronephrosis has been reported more frequently. The purpose of this
study was to identify prognostic factors associated with adverse outcome, such as renal failure and death, in fetal hydronephrosis.
One hundred and forty-eight children with fetal hydronephrosis were admitted, submitted to a systematic protocol, and prospectively
followed. Prognostic factors associated with fetal echography and clinical and laboratory findings on admission were studied.
The median follow-up was 39 months. The analysis was conducted in two steps. In a univariate analysis, variables associated
with adverse outcome were identified by the Kaplan-Meier method. The variables that were significantly associated with adverse
outcome were then included in a multivariate analysis. This analysis, using the multivariate Cox’s model, was performed to
identify variables that were independently associated with a worse prognosis. Only variables that remained independently associated
with adverse outcome were included in the final model. After final adjustment by Cox’s multivariate model, three variables
were identified as independent predictors of adverse outcome: oligohydramnios, prematurity, and glomerular filtration rate
lower than 20 ml/min. Thus, in the presence of oligohydramnios, prematurity, and abnormal renal function, the medical team
must plan appropriate follow-up for infants at health centers prepared to investigate and treat uropathies in newborns.
Received: 24 August 1998 / Revised: 7 December 1998 / Accepted: 11 December 1998 相似文献
104.
Secretory breast carcinoma is a rare tumor originally described in children and adolescent women with a characteristic morphology and a controversial choice of treatment. We report an additional case of a 4-year-old girl with a breast tumor diagnosed as a secretory carcinoma without involvement of the axillary lymph nodes. The therapy consisted of simple mastectomy and low axillary dissection. She presented with a local recurrence near the surgical scar 8 months later, and a wide elliptical excision of the scar and underlying tissue was performed with subsequent radiotherapy of the surgical bed. This tumor has a relatively benign behavior and rarely metastasizes. A literature review revealed only 22 cases of breast carcinoma in childhood and adolescence. ▪ 相似文献
105.
Bilateral macular hemorrhage after laser in situ keratomileusis 总被引:2,自引:0,他引:2
José Domingo Luna Victor Eduardo Reviglio Claudio Patricio Juárez 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》1999,237(7):611-613
· Background: This is the first report of a bilateral submacular hemorrhage after LASIK surgery in an extreme myo pic patient.
A 31-year-old man underwent bilateral surgery for correction of –16.75+0.75×70° and –16.50+0.50×55°. · Methods: Case report. ·
Results: One day after surgery the patient’s uncorrected visual acuity was in the 20/50 range OU and by 17 days after surgery
his visual acuity had declined to 20/200 range. Fundus examination showed multifocal subretinal macular and posterior pole
hemorrhages. Fluorescein angiography showed some macular lesions compatible with lacquer cracks. · Conclusions: Preoperative
and postoperative fundus examination is important to detect this phenomenon. Patients should be informed of this rare complication.
Received: 2 June 1998 Revised version received: 16 November 1998 Accepted: 17 November 1998 相似文献
106.
Psychotic symptoms are common in both the manic and depressive phases of bipolar disorder. More than half of patients with bipolar disorder will experience psychotic symptoms in their lifetime. Grandiose delusions are the most common type of psychotic symptom, but any kind of psychotic symptom, including thought disorder, hallucinations, mood-incongruent psychotic symptoms, and catatonia can present as part of a manic episode. Psychotic symptoms suggest poor prognosis when they occur in the absence of affective symptoms. However, psychotic symptoms can mask affective symptoms and make the distinction between manic-depressive illness and other psychiatric disorders difficult, especially in minorities. Careful assessment of prior psychiatric history, family history, and treatment response can aid in the differentiation of affective disorders with psychotic features from psychotic disorders. 相似文献
107.
Sialyl-Tn antigen (STn) is a mucin-type carbohydrate normally present in goblet cells of small and large bowel. STn expression has been demonstrated to occur in complete and incomplete intestinal metaplasia as well as in many carcinomas but in no normal gastric cell. The aim of our present study was to evaluate the distribution of STn in Helicobacter pylori chronic gastritis (HpCG) of pediatric patients. Eighteen gastric biopsies from 15 children (mean age: 11.5 years) with HpCG, 9 gastric biopsies from 9 children without H. pylori infection, and 1 heterotopic gastric mucosa in Meckel's diverticulum were immunostained using the anti-STn antibody STn1 (18/18), NCL-MUC-1 (7/18), and NCL-MUC-2 (18/18) antibodies. Also, sulfated mucosubstances were investigated with the Alcian Blue-Periodic Acid Schiff (AB-PAS), pH 1.0 stain. Although with different intensity (weak in 5/18, moderate 9/18, and intense 4/18) all cases with HpCG exhibited STn immunoreactivity. The expression of STn was found to be located mainly to the supranuclear region of the epithelial cells at the foveolae and glandular necks, with occasional cells showing diffuse cytoplasmic staining. When reactivity was intense, it was for the most part found in the cells at the neck of the glands. The mucus out of the luminal border above the positive cells was usually also stained. MUC-1 was negative (2/7) or weakly positive (5/7) in a few surface mucous cells. MUC-2 was negative (16/18) or occasionally detected in some foveolar and surface cells (2/18). AB-PAS pH 1.0 revealed the presence of sulfomucins in the cytoplasm of isolated cells of gastric pits and glands of most cases (11/15). None of these findings was observed in the control group. We conclude that STn can be identified in gastric cells of pediatric patients with HpCG and that this does not correlate with other mucosubtances markers. Thefindings could indicate that minimal intestinal metaplasia takes place in children with HpCG. 相似文献
108.
Antileukotrienes are a relatively new class of anti-asthma drugs that either block leukotriene synthesis (5-lipoxygenase inhibitors) like zileuton, or antagonise the most relevant of their receptors (the cysteinyl leukotriene 1 receptor [CysLT1]) like montelukast, zafirlukast or pranlukast. Hence, their major effect is an anti-inflammatory one. With the exception of pranlukast, the other antileukotrienes have been studied and marketed in the US and Europe for long enough to establish that they are useful drugs in the management of asthma. Their effects, significantly better than placebo, seem more pronounced in subjective measurements (i.e. symptoms scores or quality-of-life tests) than in objective parameters (i.e. forced expiratory volume in 1 second or peak expiratory flow rate). Also, there is some evidence that these drugs work better in some subsets of patients with certain genetic polymorphisms - probably related to their leukotriene metabolism - or patients with certain asthma characteristics. There are a small number of comparative studies only, and with regard to long-term asthma control differences between the agents have not been evaluated. Nevertheless, their overall effect appears comparable with sodium cromoglycate (cromolyn sodium) or theophylline, but significantly less than low-dose inhaled corticosteroids. Antileukotrienes have been shown to have a degree of corticosteroid-sparing effect, but salmeterol appears to perform better as an add-on drug. Montelukast is probably the most useful antileukotriene for continuous treatment of exercise-induced asthma, performing as well as salmeterol without inducing any tolerance. All antileukotrienes are taken orally; their frequency of administration is quite different ranging from four times daily (zileuton) to once daily (montelukast). Antileukotrienes are well tolerated drugs, even though zileuton intake has been related to transitional liver enzyme elevations in some cases. Also Churg-Strauss syndrome (a systemic vasculitis), has been described in small numbers of patients taking CysLT1 antagonists. It is quite probable that this disease appears as a consequence of an 'unmasking' effect when corticosteroid dosages are reduced in patients with severe asthma once CysLT1 antagonists are introduced, but more data are needed to definitely establish the mechanism behind this effect. Overall, however, the benefits of antileukotrienes in the treatment of asthma greatly outweigh their risks. 相似文献
109.
Carlos M. Villaln Eduardo Ramírez‐San Juan Araceli Snchez‐Lpez Guadalupe Bravo Edwin W. Willems Pramod R. Saxena David Centurin 《Basic & clinical pharmacology & toxicology》2003,92(4):165-172
Abstract: The present study investigated the effects of dopamine on the canine external carotid circulation. One min. intracarotid artery (i.c.) infusions of dopamine (10–310 μg min.?1) produced dose‐dependent decreases in the canine external carotid conductance without affecting blood pressure or heart rate. This effect was mimicked by the D1/2‐like receptor agonist apomorphine (1–310 μg min?1), but not by the D2‐like receptor agonist, bromocriptine (31–310 μg min.?1). In contrast, fenoldopam (1–310 μg min.?1, intracarotid), a D1‐like receptor agonist, produced dose‐dependent increases in external carotid conductance. The vasoconstrictor response to dopamine was abolished after intravenous administration of the antagonists, phentolamine (α1/2; 2000 μg kg?1) or rauwolscine (α2; 100 μg kg?1), but remained unaffected after prazosin (α1; 100 μg kg?1) or haloperidol (D2‐like; 1000 μg kg?1). Interestingly, after phentolamine not only were the vasoconstrictor responses to dopamine abolished, but even a dose‐dependent vasodilator component was unmasked. These vasodilator responses to dopamine remained unchanged after intravenous haloperidol or propranolol (1000 μg kg?1 each). On the other hand, the vasodilator responses to fenoldopam, which remained unchanged after intravenous saline (0.1 ml kg?1), propranolol (1000 μg kg?1) or vagosympathectomy, were abolished by the D1‐like receptor antagonist, SCH‐23390 (10 μg kg?1). Lastly, the responses to dopamine and fenoldopam were not significantly altered after intraperitoneal pretreatment with reserpine (5 mg kg?1; ?24 hr). The above results suggest that the canine external carotid vasoconstrictor responses to dopamine: (i) are mainly mediated by α2‐adrenoceptors; and (ii) overshadow a vasodilator component, which involves vascular D1‐like receptors. 相似文献
110.
Anita Koushik Robert W Platt Eduardo L Franco 《Cancer epidemiology, biomarkers & prevention》2004,13(1):11-22
The Arg/Arg genotype versus Arg/Pro or Pro/Pro at codon 72 of the p53 gene has been implicated as a risk marker in cervical neoplasia. However, research on this topic has produced controversial results. We reviewed the published literature to summarize the association and to identify methodological features that may have contributed to the heterogeneity. Information on specific methodological features of studies addressing this topic published between 1998 and 2002 were obtained. Study-specific odds ratios (ORs) were combined in a meta-analysis, assuming random effects. To identify characteristics that significantly contributed to heterogeneity, we used meta-regression analysis. We identified 50 articles, of which 45 were included in the meta-analyses and regressions. No evidence of association or heterogeneity was detected for preinvasive lesions. For invasive cervical cancer with undefined histology, the Arg/Arg genotype was not found to affect risk (OR, 1.1; 95% confidence interval (CI), 0.9-1.3). However, a slightly increased risk was observed for squamous cell carcinoma (OR, 1.5; 95% CI, 1.2-1.9) and adenocarcinoma (OR, 1.7; 95% CI, 1.0-2.7). Meta-regression analysis identified that the most important factor contributing to heterogeneity among results for invasive lesions was departures from Hardy-Weinberg equilibrium in the control group. Summary ORs for studies in equilibrium were essentially null. A possible susceptibility role by the p53 codon 72 polymorphism at a late carcinogenetic stage in cervical cancer cannot be ruled out. However, various methodological features can contribute to departures from Hardy-Weinberg equilibrium and consequently to less than ideal circumstances for the examination of this polymorphism. Future investigations require appropriate attention to design and methodological issues. 相似文献