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   3741篇
  免费   239篇
  国内免费   57篇
耳鼻咽喉   36篇
儿科学   92篇
妇产科学   70篇
基础医学   492篇
口腔科学   105篇
临床医学   332篇
内科学   893篇
皮肤病学   36篇
神经病学   327篇
特种医学   139篇
外国民族医学   1篇
外科学   661篇
综合类   100篇
一般理论   2篇
预防医学   119篇
眼科学   45篇
药学   342篇
  2篇
中国医学   31篇
肿瘤学   212篇
  2023年   25篇
  2022年   65篇
  2021年   97篇
  2020年   78篇
  2019年   78篇
  2018年   89篇
  2017年   79篇
  2016年   99篇
  2015年   110篇
  2014年   127篇
  2013年   153篇
  2012年   210篇
  2011年   212篇
  2010年   127篇
  2009年   111篇
  2008年   217篇
  2007年   182篇
  2006年   164篇
  2005年   181篇
  2004年   153篇
  2003年   135篇
  2002年   131篇
  2001年   75篇
  2000年   63篇
  1999年   61篇
  1998年   36篇
  1997年   26篇
  1996年   21篇
  1994年   19篇
  1992年   61篇
  1991年   54篇
  1990年   47篇
  1989年   50篇
  1988年   65篇
  1987年   58篇
  1986年   53篇
  1985年   47篇
  1984年   36篇
  1983年   20篇
  1982年   28篇
  1981年   21篇
  1979年   27篇
  1978年   26篇
  1977年   38篇
  1976年   28篇
  1974年   19篇
  1973年   24篇
  1972年   22篇
  1970年   24篇
  1967年   20篇
排序方式: 共有4037条查询结果,搜索用时 0 毫秒
91.

Purpose

A number of original publications and review articles have addressed the issue of perioperative immune modulation and cancer outcome. The objective of this module is to review current understanding surrounding the pathways involved and the evidence implicating commonly used anesthetic agents.

Principal findings

Drugs commonly used in anesthetic practice have been shown to affect various components of the immune system in laboratory animal and human in vitro models. It has been hypothesized that these effects may favour tumour recurrence and metastasis formation. Inhalational agents and opiates have potential negative immunomodulatory effects; on the other hand, regional anesthesia and propofol may have positive effects on immune function modulation. However, the clinical relevance of these studies to human cancer outcome is unknown since clinical trials are equivocal, and results of in vitro and animal model studies cannot be extrapolated to clinical practice. Furthermore, there is a lack of rigorous clinical trials demonstrating clinical outcome benefit for one technique over another. It remains unclear how anesthetic drugs influence the immune system in relation to tumour cell elimination and clinical cancer outcome.

Conclusions

Recommendations for a specific anesthetic technique based on cancer outcome alone cannot be made. A pragmatic solution would be to offer regional anesthesia in isolation or combined with propofol infusion to cancer patients if appropriate and if local expertise is available. Regional anesthesia offers excellent analgesia, a low incidence of postoperative nausea and vomiting, and a favourable immunological profile based on current understanding of laboratory evidence.  相似文献   
92.
In the last decade, the number of patients starting dialysis after a failed kidney transplant has increased substantially. These patients appear to be different from their transplant‐naïve counterparts, and so may be the timing of dialysis therapy initiation. An increasing number of studies suggest that in transplant‐naïve patients, later dialysis initiation is associated with better outcomes. Very few data are available on timing of dialysis reinitiation in failed transplant recipients, and they suggest that an earlier return to dialysis therapy tended to be associated with worse survival, especially among healthier and younger patients and women. Failed transplant patients may also have unique issues such as continuation of immunosuppression versus withdrawal or the need for remnant allograft nephrectomy with regard to dialysis reinitiation. These patients may have a different predialysis preparation work‐up, worse blood pressure control, higher or lower serum phosphorus levels, lower serum bicarbonate concentration, and worse anemia management. The choice of dialysis modality may also represent an important question for these patients, even though there appears to be no difference in mortality between patients starting peritoneal versus hemodialysis. Finally, failed transplant patients returning to dialysis appear to have a higher mortality rate compared with transplant‐naïve incident dialysis patients, especially in the first several months of dialysis therapy. In this review, we will summarize the available data related to the timing of dialysis initiation and outcomes in failed kidney transplant patients after returning to dialysis.  相似文献   
93.

Purpose

The aim of the study was to compare the characteristics of ventriculosubgaleal shunts during the clinical course of posthemorrhagic and postinfectious hydrocephalus in the neonatal period.

Patients and methods

The study comprised 102 premature babies in whom subgaleal shunt was consecutively inserted between 2006 and 2011. Seventy-two patients had posthemorrhagic hydrocephalus (mean gestational age 27.3?±?2.1 weeks, mean birth weight 1,036.9?±?327.7 g, mean age at insertion 51.4?±?56.2 days) and 30 patients were operated postinfectiously (27.5?±?2.2 weeks, 1,064.7 g?±?310.7 g, 115.9?±?47.8 days).

Results

The mean survival of subgaleal shunts was 87.9 days for the posthemorrhagic group and 75.6 days for the postinfectious group. Only six infants (8.3 %) did not need ventriculoperitoneal shunts later, all posthemorrhagic. There were meaningful differences between two groups with regard to ventriculosubgaleal shunt-related infections (8.3 % in posthemorrhagic versus 20.0 % in postinfectious) and shunt revision rate (6.9 % in posthemorrhagic versus 13.3 % in postinfectious), but these were not statistically significant. The need of ventriculoscopic procedures was notably more frequent in postinfectious group (1.4 versus 23.3 %).

Conclusion

In premature infants with ventriculomegaly, the subgaleal shunt is an effective temporary diversion tool. The complications were less with posthemorrhagic than with postinfectious hydrocephalus. With previous severe infections of prematures, the risk for complications regarding infection and obstruction will be 2.75 and 2.06 (odds ratios) times higher and more frequent need of ventriculoscopic procedures should be considered (odds ratio 21.6).  相似文献   
94.
Hypertension in the elderly substantially contributes to cerebromicrovascular damage and promotes the development of vascular cognitive impairment. Despite the importance of the myogenic mechanism in cerebromicrovascular protection, it is not well understood how aging affects the functional adaptation of cerebral arteries to high blood pressure. Hypertension was induced in young (3 months) and aged (24 months) C57/BL6 mice by chronic infusion of angiotensin II (AngII). In young hypertensive mice, the range of cerebral blood flow autoregulation was extended to higher pressure values, and the pressure-induced tone of middle cerebral artery (MCA) was increased. In aged hypertensive mice, autoregulation was markedly disrupted, and MCAs did not show adaptive increases in myogenic tone. In young mice, the mechanism of adaptation to hypertension involved upregulation of the 20-HETE (20-hydroxy-5,8,11,14-eicosatetraenoic acid)/transient receptor potential cation channel, subfamily C (TRPC6) pathway and this mechanism was impaired in aged hypertensive mice. Downstream consequences of cerebrovascular autoregulatory dysfunction in aged AngII-induced hypertensive mice included exacerbated disruption of the blood–brain barrier and neuroinflammation (microglia activation and upregulation of proinflammatory cytokines and chemokines), which were associated with impaired hippocampal dependent cognitive function. Collectively, aging impairs autoregulatory protection in the brain of mice with AngII-induced hypertension, potentially exacerbating cerebromicrovascular injury and neuroinflammation.  相似文献   
95.
PurposeThe aim of this survey was to review and compare the current approaches to epilepsy management in Central and Eastern EU (CEEU) countries.MethodThe questionnaire was sent to ten invited experts from Bulgaria, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania, Slovakia, and Slovenia. It focused on the treatment of adults.ResultsThe number of neurologists and epilepsy reference centers is highly variable in CEEU countries. None of the analyzed states has a formal specialization in epileptology. No universal state-approved criteria for reference centers exist in Czech Republic, Estonia, Hungary, Latvia, and Slovenia. Generally, the protocols for epilepsy treatment in CEEU countries, including drug-resistant epilepsy, are in accordance with international guidelines; however, most countries have their own national standards of care and some have local clinical guidelines. Also, the reimbursement systems for antiepileptic drugs in CEEU countries are highly variable. Seven countries have epilepsy surgery centers. The costs of epilepsy surgeries are fully reimbursed, procedures performed abroad may also be covered. The length of time spent on waiting lists for surgery following the completion of preoperative investigations varies from two weeks to three years. The fraction of patients who qualified and were operated on within 12 months ranges from 20% to 100%.ConclusionThe lack of unified procedures pertaining to the evaluation and therapy of epilepsy is reflected by marked differences in access to treatment modalities for patients from CEEU countries.  相似文献   
96.
97.
Sharif  Ban  Saifuddin  Asif 《Skeletal radiology》2019,48(1):149-150
Skeletal Radiology -  相似文献   
98.
Sharif  Ban  Saifuddin  Asif 《Skeletal radiology》2019,48(1):175-176
Skeletal Radiology -  相似文献   
99.
Resistin is an adipocytokine that is associated with inflammation, coronary artery disease, and other types of cardiovascular disease among patients with normal kidney function. However, little is known about the association of resistin with outcomes in kidney transplant recipients. We collected socio‐demographic and clinical parameters, medical and transplant history, and laboratory data from 988 prevalent kidney transplant recipients enrolled in the Malnutrition‐Inflammation in Transplant—Hungary Study (MINIT‐HU study). Serum resistin levels were measured at baseline. Associations between serum resistin level and death with a functioning graft over a 6‐year follow‐up period were examined in unadjusted and adjusted models. The mean±SD age of the study population was 51 ± 13 years, among whom 57% were men and 21% were diabetics. Median serum resistin concentrations were significantly higher in patients who died with a functioning graft as compared to those who did not die during the follow‐up period (median [IQR]: 22[15–26] vs. 19[14–22] ng/ml, respectively; P < 0.001). Higher serum resistin level was associated with higher mortality risk in both unadjusted and fully adjusted models: HRs (95% CI): 1.33(1.16–1.54) and 1.21(1.01–1.46), respectively. In prevalent kidney transplant recipients, serum resistin was an independent predictor of death with a functioning graft.  相似文献   
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