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   874篇
  免费   54篇
  国内免费   17篇
耳鼻咽喉   9篇
儿科学   36篇
妇产科学   27篇
基础医学   91篇
口腔科学   23篇
临床医学   90篇
内科学   290篇
皮肤病学   5篇
神经病学   56篇
特种医学   68篇
外科学   103篇
综合类   11篇
预防医学   31篇
眼科学   5篇
药学   27篇
中国医学   1篇
肿瘤学   72篇
  2023年   2篇
  2022年   8篇
  2021年   17篇
  2020年   15篇
  2019年   12篇
  2018年   18篇
  2017年   13篇
  2016年   13篇
  2015年   17篇
  2014年   27篇
  2013年   32篇
  2012年   41篇
  2011年   40篇
  2010年   35篇
  2009年   47篇
  2008年   33篇
  2007年   37篇
  2006年   37篇
  2005年   24篇
  2004年   31篇
  2003年   30篇
  2002年   28篇
  2001年   19篇
  2000年   33篇
  1999年   26篇
  1998年   36篇
  1997年   33篇
  1996年   24篇
  1995年   17篇
  1994年   23篇
  1993年   8篇
  1992年   11篇
  1991年   13篇
  1990年   10篇
  1989年   14篇
  1988年   13篇
  1987年   15篇
  1986年   22篇
  1985年   23篇
  1984年   7篇
  1983年   3篇
  1982年   11篇
  1981年   3篇
  1980年   2篇
  1978年   2篇
  1977年   2篇
  1972年   3篇
  1968年   2篇
  1967年   2篇
  1963年   2篇
排序方式: 共有945条查询结果,搜索用时 562 毫秒
91.
The management of adult patients with Chiari malformation associated with syrinx remains controversial. Although an abundance of literature exists for the pediatric population, there is an absence of guidelines for the adult population. It is unclear which of the different surgical approaches is appropriate in patients with Chiari I malformations and syringomyelia. A 36-year-old female patient had a posterior fossa decompression 3 years prior to recurrence. The patient developed recurrent symptoms with sensory loss and hyperesthesia in the right upper extremity. MRI revealed decreased cerebrospinal fluid flow at the craniocervical junction. The patient was taken to the operating room for revision of the posterior fossa decompression, lysis of adhesions and duraplasty. Re-exploration of a Chiari decompression, lysis of adhesions and revision duraplasty is an effective treatment option for recurrent syringomyelia.  相似文献   
92.
The discovery of human Metapneumovirus (hMPV) and human Bocavirus (hBoV) identified the etiological causes of several cases of acute respiratory tract infections in children. This report describes the molecular epidemiology of hMPV and hBoV infections observed following viral surveillance of children hospitalized for acute respiratory tract infections in Milan, Italy. Pharyngeal swabs were collected from 240 children ≤3 years of age (130 males, 110 females; median age, 5.0 months; IQR, 2.0-12.5 months) and tested for respiratory viruses, including hMPV and hBoV, by molecular methods. hMPV-RNA and hBoV-DNA positive samples were characterized molecularly and a phylogenetical analysis was performed. PCR analysis identified 131/240 (54.6%) samples positive for at least one virus. The frequency of hMPV and hBoV infections was similar (8.3% and 12.1%, respectively). Both infections were associated with lower respiratory tract infections: hMPV was present as a single infectious agent in 7.2% of children with bronchiolitis, hBoV was associated with 18.5% of pediatric pneumonias and identified frequently as a single etiological agent. Genetically distinct hMPV and hBoV strains were identified in children examined with respiratory tract infections. Phylogenetic analysis showed an increased prevalence of hMPV genotype A (A2b sublineage) compared to genotype B (80% vs. 20%, respectively) and of the hBoV genotype St2 compared to genotype St1 (71.4% vs. 28.6%, respectively). Interestingly, a shift in hMPV infections resulting from A2 strains has been observed in recent years. In addition, the occurrence of recombination events between two hBoV strains with a breakpoint located in the VP1/VP2 region was identified.  相似文献   
93.
94.
Patients with chromosome 22q11 deletion syndrome exhibit significant phenotypic variability. Epidemiologic data suggest a higher incidence in Hispanics, but limited clinical information is available from Latin-American patients. We describe the clinical features of Chilean patients with 22q11 deletion syndrome and compare their findings with those reported in large European, Japanese and US series. Data were obtained from 208 patients from five medical centers. Mean age at diagnosis was 5.2 years, with a median of 2.3 years. Congenital heart defects were present in 59.6%, lower than other large series that averaged 75.8%. Palate abnormalities were present in 79%, higher than previous reports averaging 56%. Patients with congenital heart disease were diagnosed earlier (median 0.3 years of age) than those without heart defects (median 5.6 years) and had greater mortality attributable to the syndrome (9.8% vs 2.4%, respectively). The differences in frequencies of major anomalies may be due to growing awareness of more subtle manifestations of the syndrome, differences in clinical ascertainment or the presence of modifier factors. These observations provide additional data useful for patient counseling and for the proposal of health care guidelines.  相似文献   
95.

Background and purpose:

α- and β-amyrin are pentacyclic triterpenes found in plants and are known to exhibit pronounced anti-inflammatory effects. Here, we evaluated the effects of a 1:1 mixture of α- and β-amyrin (α,β-amyrin) on an experimental model of colitis in mice.

Experimental approach:

Colitis was induced in Swiss male mice by trinitrobenzene sulphonic acid (TNBS) and followed up to 72 h; animals were treated systemically with α,β-amyrin, dexamethasone or vehicle. Macro- and microscopic damage, myeloperoxidase activity and cytokine levels were assessed in colons. Histological sections were immunostained for cyclooxygenase-2 (COX-2), vascular endothelial growth factor, phospho-p65 nuclear factor-κB (NF-κB) and phospho-cyclic AMP response element-binding protein (CREB)

Key results:

TNBS-induced colitis was associated with tissue damage, neutrophil infiltration and time-dependent increase of inflammatory mediators. Treatment with α,β-amyrin (3 mg·kg−1, i.p.) or dexamethasone (1 mg·kg−1, s.c.) consistently improved tissue damage scores and abolished polymorphonuclear cell infiltration. α,β-Amyrin, like dexamethasone, significantly diminished interleukin (IL)-1β levels and partially restored IL-10 levels in colon tissues 72 h after colitis induction, but only α,β-amyrin reduced vascular endothelial growth factor expression by immunohistochemistry. The colonic expression of COX-2 at 24 h and that of phospho-NF-κB and phospho-CREB (peaking at 6 h) after colitis induction were consistently inhibited by both α,β-amyrin and dexamethasone.

Conclusions and implications:

Systemic administration of α,β-amyrin exerted a marked and rapid inhibition of TNBS-induced colitis, related to the local suppression of inflammatory cytokines and COX-2 levels, possibly via inhibition of NF-κB and CREB-signalling pathways. Taken together, our data suggest a potential use of α,β-amyrin to control inflammatory responses in bowel disease.  相似文献   
96.
97.
Summary  A young woman suffering from S. pneumoniae meningitis developed intractable intracranial hypertension with a GCS of 3. Intracranial pressure (ICP) ranged above 30 mmHg despite maximal medical treatment and continuous CSF drainage. We performed a wide bilateral decompressive craniectomy (DC) with duraplasty and we observed an immediate and stable drop of her ICP. When discharged she was independent. DC has been rarely used to control ICP in encephalitis patients and recently only in one case of meningitis. This operation could be a valuable option when all other measures to decrease ICP have failed; when necessary, it should be performed according to some rules otherwise it could be harmful for the patient. Conclusive data on the impact of DC on the final outcome of such patients are not available yet. Correspondence: Alessandro Perin, Neurochirurgia, Ospedale Regionale di Treviso, Treviso, Italy.  相似文献   
98.
OBJECTIVE—Heat shock protein 27 (HSP27) is a member of the small heat shock protein family of proteins. HSP27 expression is enhanced in target tissues of diabetic microvascular complications, and changes in circulating serum HSP27 levels (sHSP27) have been reported in patients with macrovascular disease. We investigated whether sHSP27 levels were associated with micro- and macrovascular complications in type 1 diabetic patients.RESEARCH DESIGN AND METHODS—A cross-sectional, nested, case-control study from the EURODIAB Prospective Complications Study of 531 type 1 diabetic patients was performed. Case subjects (n = 363) were defined as those with one or more complications of diabetes; control subjects (n = 168) were defined as those with no evidence of any complication. We measured sHSP27 levels and investigated their associations with diabetes complications.RESULTS—Mean sHSP27 levels were significantly higher in case subjects with distal symmetrical polyneuropathy (DSP) than in control subjects, even after adjustment for age and albumin excretion rate (AER) (785.9 vs. 574.7 pg/ml, P = 0.03). In logistic regression analysis, sHSP27 levels in the upper quartile were associated with a twofold increased odds ratio (OR) of DSP, independently of conventional risk factors, markers of inflammation, and AER (OR 2.41 [95% CI 1.11–5.24]).CONCLUSIONS—In this large cohort of type 1 diabetic subjects, we found an independent association between sHSP27 and DSP. This suggests that sHSP27 levels may be a novel marker for diabetic neuropathy.Heat shock protein 27 (HSP27), a member of the small heat shock protein family of proteins, is a highly conserved peptide of ∼27 kDa associated with cytoskeletal actin (1). In addition to its chaperone activity, HSP27 acts as a filament stabilizer under stress conditions, interferes with apoptotic pathways, and participates in cytoskeletal dynamics by controlling actin polymerization (2). Therefore, HSP27 plays an important role in both cytoprotection and cell motility.Recent studies in experimental diabetes have shown HSP27 overexpression in glomeruli (3), dorsal root ganglia (4,5), retina (6), and the area adjacent to atherosclerotic plaque (7), indicating HSP27 induction in target tissues of diabetes complications. HSP27 is also released into circulation (8). A pilot study has shown reduced plasma HSP27 levels in patients with carotid stenosis (9), but in a more recent study, HSP27 levels were increased in patients with acute coronary syndromes (7). However, no large study is yet available on circulating HSP27 in vascular disease.Type 1 diabetes is associated with a greatly increased risk of vascular complications that cannot be completely accounted for by conventional risk factors. The aim of the present study was to assess whether high serum HSP27 (sHSP27) levels increased odds ratios (ORs) of micro- and macrovascular complications in a nested case-control sample of type 1 diabetic individuals from the EURODIAB Prospective Complications Study.  相似文献   
99.
100.
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