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   1649784篇
  免费   134306篇
  国内免费   2803篇
耳鼻咽喉   22368篇
儿科学   54136篇
妇产科学   46984篇
基础医学   233624篇
口腔科学   48291篇
临床医学   145962篇
内科学   324531篇
皮肤病学   34710篇
神经病学   134931篇
特种医学   66261篇
外国民族医学   474篇
外科学   251801篇
综合类   40201篇
现状与发展   3篇
一般理论   599篇
预防医学   126548篇
眼科学   37505篇
药学   124083篇
  6篇
中国医学   3018篇
肿瘤学   90857篇
  2018年   15885篇
  2016年   13866篇
  2015年   16084篇
  2014年   22191篇
  2013年   33572篇
  2012年   45935篇
  2011年   48523篇
  2010年   28380篇
  2009年   27215篇
  2008年   46281篇
  2007年   48687篇
  2006年   49414篇
  2005年   48077篇
  2004年   47276篇
  2003年   45284篇
  2002年   44162篇
  2001年   76024篇
  2000年   78631篇
  1999年   66791篇
  1998年   18279篇
  1997年   16802篇
  1996年   16757篇
  1995年   16425篇
  1994年   15404篇
  1993年   14507篇
  1992年   55661篇
  1991年   53946篇
  1990年   52726篇
  1989年   50961篇
  1988年   47389篇
  1987年   46696篇
  1986年   44433篇
  1985年   42990篇
  1984年   32208篇
  1983年   27760篇
  1982年   16422篇
  1981年   14676篇
  1980年   13744篇
  1979年   30540篇
  1978年   21180篇
  1977年   17859篇
  1976年   16756篇
  1975年   17620篇
  1974年   21536篇
  1973年   20715篇
  1972年   18870篇
  1971年   17783篇
  1970年   16299篇
  1969年   15284篇
  1968年   13953篇
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
991.
992.
993.
994.
995.
OBJECTIVES: Local anaesthetic infiltration into the carotid sinus during carotid endarterectomy (CEA) has been recommended to minimise blood pressure fluctuations but its use remains controversial. The aim of this meta-analysis was to determine whether intra-operative administration of local anaesthetic reduces the incidence of haemodynamic instability following CEA. MATERIALS AND METHODS: A search of the Medline, Pubmed and Embase databases and the Current Controlled Trials register identified four trials, which met the pre-defined inclusion criteria for data extraction. Pooled odds ratios with 95 per cent confidence intervals (c.i.) for the development of post-operative hypotension and hypertension were calculated using a random-effects model. RESULTS: Outcomes of 432 patients were studied. Local anaesthetic blockade of the carotid sinus was associated with a pooled odds ratio of 1.25 (95 per cent c.i. 0.496 to 3.15); p=0.216) and 1.28 (95 per cent c.i. 0.699 to 2.33; p=0.428) for the development of post-operative hypotension and hypertension respectively. Although none reach significance there was a trend towards increased risk of developing a complication in those patients who received local anaesthetic. CONCLUSIONS: There are insufficient data to determine the role of intra-operative local anaesthetic administration in reducing post-operative blood pressure lability following CEA. Conversely, the possibility of harm cannot be excluded on the basis of the currently available data.  相似文献   
996.
997.
Human leukocyte antigen (HLA) compatibility has no clinically significant impact in cadaveric liver transplantation. Less is known regarding living-donor liver transplantation (LDLT). Our prior analysis of the Organ Procurement and Transplantation Network (OPTN) database suggested a higher graft failure rate in patients who underwent LDLT from donors with close HLA match. We further investigated the effect of HLA-A, -B, and -DR matching on 5-yr graft survival in adult LDLT by analyzing OPTN data regarding adult LDLT performed between 1998 and 2005. We evaluated associations between 5-yr graft survival and total, locus-specific, and haplotype match levels. Separate analyses were conducted for recipients with autoimmune (fulminant autoimmune hepatitis, cirrhosis secondary to autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis) or nonautoimmune liver disease. Multivariable Cox proportional hazard models were used to evaluate interactions and adjust for potential confounders. Among 631 patients with available donor/recipient HLA data, the degree of HLA match had no significant effect on 5-yr graft survival, even when analyzed separately in recipients with autoimmune vs. nonautoimmune liver disease. To be able to include all 1,838 adult LDLTs, we considered a first-degree related donor as substitute for a close HLA match. We found no difference in graft survival in related vs. unrelated pairs. In conclusion, our results show no detrimental impact of close HLA matching on graft survival in adult LDLT, including in recipients with underlying autoimmune liver disease.  相似文献   
998.
Klippel-Feil syndrome (KFS) is a heterogeneous entity, characterized by specific congenital anomalies of segmentation of the cervical spine. We report a case of KFS plus atretic meningocele in one identical twin and anencephaly in the other. These identical twins were both male with no chromosome defect. One of them had anencephaly diagnosed at the gestational age of 17 weeks and died soon after birth, whereas the co-twin had KFS with multiple congenital anomalies including short neck with low hairline, occipital atretic meningocele, butterfly vertebrae, hemivertebrae, cervico-thoracic scoliosis, left thumb preaxial polydactyly, and right undescended testis. He received rehabilitation during infancy and could walk at the age of 15 months. Both of these infants had preaxial polydactyly, which is an uncommon anomaly associated with KFS. In conclusion, iniencephaly and anencephaly are probably the extreme manifestations of KFS rather than different dysraphisms. Prompt clinical suspicion with early diagnostic imaging for spine lesions and occult opening of neural tube is mandatory for further intervention and rehabilitation.  相似文献   
999.
OBJECTIVE: The authors described the influence of specific medical conditions on clinical remission and response of major depression (MDD) in a clinical trial evaluating a care-management intervention among older primary-care patients. METHODS: Adults age 60 years and older were randomly selected and screened for depression. Participants were randomly assigned to Usual Care or to an Intervention with a depression care-manager offering algorithm-based care for MDD. In all, 324 adults meeting criteria for MDD were included in these analyses. Remission and response was defined by a score on the Hamilton Rating Scale for Depression <10 and by a decrease from baseline of > or =50%, respectively. Medical comorbidity was ascertained through self-report. Cognitive impairment was defined by a score <24 on the Mini-Mental State Exam (MMSE). RESULTS: In Usual Care, rates of remission were faster in persons who reported atrial fibrillation (AF) than in persons who did not report AF and slower in persons who reported chronic pulmonary disease than in persons who did not report chronic pulmonary disease; rates of response were less stable in persons with MMSE <24 than in those with MMSE > or =24. In the Intervention condition, none of the specific chronic medical conditions were significantly associated with outcomes for MDD. CONCLUSIONS: Because disease-specific findings were observed in persons who received Usual Care but not in persons who received more intensive treatment in the Intervention condition, our results suggest that the association of medical comorbidity and treatment outcomes for MDD may be determined by the intensity of treatment for depression.  相似文献   
1000.
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