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   1119篇
  免费   98篇
  国内免费   4篇
耳鼻咽喉   1篇
儿科学   28篇
妇产科学   19篇
基础医学   148篇
口腔科学   54篇
临床医学   134篇
内科学   164篇
皮肤病学   14篇
神经病学   61篇
特种医学   75篇
外科学   194篇
综合类   19篇
预防医学   103篇
眼科学   7篇
药学   131篇
肿瘤学   69篇
  2021年   18篇
  2020年   15篇
  2019年   15篇
  2018年   21篇
  2017年   8篇
  2016年   14篇
  2015年   17篇
  2014年   18篇
  2013年   33篇
  2012年   32篇
  2011年   35篇
  2010年   42篇
  2009年   54篇
  2008年   53篇
  2007年   36篇
  2006年   54篇
  2005年   40篇
  2004年   39篇
  2003年   37篇
  2002年   29篇
  2001年   28篇
  2000年   27篇
  1999年   30篇
  1998年   35篇
  1997年   22篇
  1996年   17篇
  1995年   12篇
  1994年   12篇
  1993年   18篇
  1992年   26篇
  1991年   30篇
  1990年   32篇
  1989年   32篇
  1988年   37篇
  1987年   21篇
  1986年   19篇
  1985年   25篇
  1984年   14篇
  1983年   9篇
  1982年   9篇
  1981年   12篇
  1980年   12篇
  1979年   19篇
  1978年   8篇
  1977年   8篇
  1976年   10篇
  1975年   10篇
  1973年   7篇
  1972年   9篇
  1969年   7篇
排序方式: 共有1221条查询结果,搜索用时 15 毫秒
71.
72.
Hanging as a method of attempting suicide is increasing in incidence. A retrospective review of victims of hanging injuries presenting to our institution over a 5-year period was performed. Forty-two cases were reviewed. Drug and/or alcohol ingestion was identified in 70% of cases. There were no cervical spine injuries identified, although two unexpected thoracic spine fractures were found. There was an 88% survival rate, with a low incidence (5%) of poor neurological outcome. The Glasgow Coma Score at scene or on arrival at hospital was found to be a prognostic indicator. Victims without spontaneous cardiac output at scene did not survive, even if cardiopulmonary resuscitation was successful initially.  相似文献   
73.
OBJECTIVE: To report the occurrence of life-threatening hyperkalaemia following treatment with therapeutic thiopentone coma. SETTING: The neurosurgical intensive care units of Royal North Shore Hospital and Liverpool Hospital, Sydney, Australia. PATIENTS: Three patients treated with theraputic thiopentone coma. One patient with raised intracranial pressure secondary to a severe traumatic brain injury and two patients with refractory vasospasm secondary to subarachnoid haemorrhage. Two of the three patients developed hypokalaemia on starting thiopentone, which was resistant to potassium supplementation. All three patients developed severe hyperkalaemia during the recovery phase of coma. This was life-threatening in all three patients and fatal in one. CONCLUSIONS: Severe hypokalaemia refractory to potassium therapy may occur during therapeutic thiopentone coma. Severe rebound hyperkalaemia may occur after cessation of thiopentone infusion. Protocols for the management of patients with therapeutic barbiturate coma should recognise this potentially serious complication.  相似文献   
74.
Serum paraoxonase (PON1) is a high-density lipoprotein (HDL) associated protein, which plays a critical role in the pathogenesis of atherosclerosis, although it was primarily associated with the hydrolysis of organophosphorus compounds. PON1 was initially thought to be independent from physiological or pathological states, although recently some environmental factors have been reported to modulate its activity. In this study, we have investigated the promoter (PON1 -108C/T and -909 C/G) and coding region (PON1 192Q/R and 55L/M) polymorphisms, as well as PON1 activity towards different substrates (paraoxon, phenylacetate and diazoxon) in 102 individuals with long term low dose exposure to pesticides in a plastic greenhouse setting (sprayers), who are probably the group of agricultural workers with the highest exposure to pesticides. PON1 activity towards paraoxon was nonsignificantly decreased (up to 53.5%) in the sprayers subgroup exposed to organophosphates (n = 41) compared with nonsprayers acting as controls (n = 39). None of the genotypes studied was associated significantly with the subgroup of individuals exposed to organophosphates, although differences between sprayers and nonsprayers were observed in the PON1 -909 G/C polymorphism. Among the environmental factors that significantly predicted lower rates of PON1 activity towards paraoxon are, interestingly, the exposure to organophosphates and current smoking. By contrast, the utilization of protective clothing while spraying pesticides inside the greenhouses was positively associated with PON1 activity, very likely by preventing the pesticides from being absorbed. This study suggests that chronic exposure to pesticides might decrease PON1 activity and pinpoints the potential usefulness of monitoring PON1 activity in occupational settings where exposure to organophosphates occurs.  相似文献   
75.
Using data from the Ghana Demographic and Health Survey 1998, this paper analyzed the duration of use of a contraceptive method and the reasons for its non-use given by former users of contraception. The results showed that the duration of use tended to be short, particularly so for the use of condom and withdrawal. Injectable contraceptives and periodic abstinence tended to be used for relatively long periods. After type of method, a woman's age and residence (urban or rural) were the most significant predictors of duration of use. The reasons for not currently using contraception given by significant numbers of former users of pill and injectable contraceptives should concern service providers and educators.  相似文献   
76.
77.
The results from several genome scans indicate that chromosome 2q21-q33 is likely to contain an autism susceptibility locus. We studied the potential contribution of nine positional and functional candidate genes: TBR-1; GAD1; DLX1; DLX2; cAMP-GEFII; CHN1; ATF2; HOXD1 and NEUROD1. Screening these genes for DNA variants and association analysis using intragenic single nucleotide polymorphisms did not provide evidence for a major role in the aetiology of autism. Four rare nonsynonymous variants were identified, however, in the cAMP-GEFII gene. These variants were present in five families, where they segregate with the autistic phenotype, and were not observed in control individuals. The significance of these variants is unclear, as their low frequency in IMGSAC families does not account for the relatively strong linkage signal at the 2q locus. Further studies are needed to clarify the contribution of cAMP-GEFII gene variants to autism susceptibility.  相似文献   
78.
Analysis of reelin as a candidate gene for autism   总被引:2,自引:0,他引:2  
Genetic studies indicate that chromosome 7q is likely to contain an autism susceptibility locus (AUTS1). We have followed a positional candidate gene approach to identify relevant gene(s) and report here the analysis of reelin (RELN), a gene located under our peak of linkage. Screening RELN for DNA changes identified novel missense variants absent in a large control group; however, the low frequency of these mutations does not explain the relatively strong linkage results on 7q. Furthermore, analysis of a previously reported triplet repeat polymorphism and intragenic single nucleotide polymorphisms, using the transmission disequilibrium test, provided no evidence for association with autism in IMGSAC and German singleton families. The analysis of RELN suggests that it probably does not play a major role in autism aetiology, although further analysis of several missense mutations is warranted in additional affected individuals.  相似文献   
79.
Trauma systems     
Trauma is one of the major causes of death and disability in modern society, particularly for the young. Organized trauma systems reduce mortality and morbidity from trauma. An effective trauma system addresses all aspects of trauma care, from prevention to rehabilitation. Well-developed trauma systems are currently available only to a minority of the world's population. Trauma systems in developed nations have much potential for improvement.  相似文献   
80.
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