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   3314篇
  免费   203篇
  国内免费   27篇
耳鼻咽喉   22篇
儿科学   161篇
妇产科学   47篇
基础医学   367篇
口腔科学   67篇
临床医学   244篇
内科学   580篇
皮肤病学   44篇
神经病学   483篇
特种医学   302篇
外科学   359篇
综合类   80篇
一般理论   3篇
预防医学   310篇
眼科学   246篇
药学   125篇
中国医学   2篇
肿瘤学   102篇
  2021年   27篇
  2019年   39篇
  2018年   47篇
  2017年   45篇
  2016年   71篇
  2015年   46篇
  2014年   69篇
  2013年   102篇
  2012年   150篇
  2011年   149篇
  2010年   89篇
  2009年   85篇
  2008年   124篇
  2007年   134篇
  2006年   109篇
  2005年   140篇
  2004年   132篇
  2003年   107篇
  2002年   110篇
  2001年   97篇
  2000年   114篇
  1999年   89篇
  1998年   52篇
  1997年   73篇
  1996年   49篇
  1995年   45篇
  1994年   35篇
  1993年   37篇
  1992年   62篇
  1991年   68篇
  1990年   62篇
  1989年   79篇
  1988年   77篇
  1987年   66篇
  1986年   63篇
  1985年   66篇
  1984年   49篇
  1983年   41篇
  1982年   40篇
  1981年   28篇
  1980年   25篇
  1979年   44篇
  1978年   33篇
  1977年   31篇
  1975年   27篇
  1974年   27篇
  1973年   32篇
  1970年   24篇
  1969年   23篇
  1968年   26篇
排序方式: 共有3544条查询结果,搜索用时 15 毫秒
21.
An infant girl with elevated blood lactate, pyruvate, and plasma branched-chain amino acids was diagnosed with dihydrolipoamide dehydrogenase (E3; dihydrolipoamide: NAD+ oxidoreductase, EC 1.8.1.4) deficiency. Activities of the pyruvate dehydrogenase complex and E3 from patient were 26 and 2% of controls in blood lymphocytes, and 11 and 14% in cultured skin fibroblasts, respectively. Western blot analysis demonstrated that the amount of E3 protein in fibroblasts from the patient and her father was about half of controls, while Northern blot analysis showed normal amounts of E3 RNA. DNA sequencing of cloned full-length E3 cDNAs from the patient revealed two mutations in separate alleles. One is a single base insertion of an extra adenine in the last codon of the leader peptide sequence (TAC-->TAAC) leading to a nonsense mutation which results in the premature termination of the precursor E3 polypeptide (Y35X). The other is a missense mutation due to substitution of guanine for adenine, causing an Arg-->Gly substitution at amino acid 460 of the mature protein (R460G) which triggers the loss of E3 activity probably by structural change in the E3 dimer. DNA sequencing of E3 cDNAs from the parents demonstrated that the nonsense mutation was inherited from the father and the missense mutation was inherited from the mother.   相似文献   
22.
23.
Major depression in panic disorder patients with comorbid social phobia   总被引:1,自引:0,他引:1  
Rates of depression among panic disorder patients are particularly elevated in patients with comorbid social phobia. However, it is unclear whether this association is specific to social phobia, or whether any comorbid anxiety disorder increases the risk of depression. We assessed 100 panic disorder patients and found a significantly higher incidence of lifetime major depression for panic patients with comorbid social phobia or generalized anxiety disorder (GAD). Panic patients with comorbid social phobia had significantly higher scores on measures of dysfunctional attitudes and lower scores on measures of assertiveness; these variables may mediate the link between social phobia and depression in this population.  相似文献   
24.
Radiologic evaluation of the skeleton and scanning electron microscopic studies of the teeth were performed on an infant boy with a lethal osteogenesis imperfecta (OI) syndrome who died at 10 mo of pneumonia. The skeletal findings included ribs that were focally expanded by fracture calluses, flat vertebral bodies, and wide limb bones. On fractured tooth surfaces, the enamel and dentin were normal as was the dentin calcification front. Although microscopic abnormalities have been noted in teeth from previously reported infants with lethal OI, a few studies also report infants with normal teeth. These differences in dental findings may indicate heterogeneity in OI lethal in infancy. Results of our study indicate that, until the primary biochemical defects in the OI syndromes are elucidated, examination of teeth from other infants with lethal OI and detailed evaluation of other clinical and skeletal features will aid in delineating heterogeneity and variation in expression in lethal OI.  相似文献   
25.
We compared the prevalence of learning disabilities at age 8 years in a subgroup of 68 of 129 (53%) regional cohort of extremely low birth weight (ELBW) children who were considered "normal" neurologically and intellectually (IQ greater than or equal to 85) with that of 114 term group matched controls (C). Both groups were tested with a battery of psychoeducational measures, and parents and teachers completed questionnaires on the school performance of the children. ELBW children were comparable with C on measures of intelligence (ELBW 101 +/- 8, C 104 +/- 11), language, and academic achievement but fared significantly less well in motor performance (p less than .0001). The prevalence of learning disabilities (by predefined criteria) in ELBW children (26%) was not increased compared with C (19%). However, teachers rated significantly more ELBW children as performing below grade level than were C (31% vs 16%, p less than .05), and by parent report, a higher proportion of ELBW children had received special assistance in school compared with C (37% vs 16%, p less than .001). We conclude that although the prevalence of learning disabilities in normal ELBW children was not different from that in controls, ELBW children did less well and utilized more special resources.  相似文献   
26.
Infection stones in the urinary tract are always associated with infection with a urease-producing, urea-splitting organism. The most common of these organisms are easy to culture and identify and can be treated early either with an appropriate antibiotic or with an anti-urease agent. Ureaplasma urealyticum and Corynebacterium urealyticum are urease-producing organisms which are difficult to grow; their presence and effects frequently go undetected and untreated. Other organisms, as yet unknown, may also be involved in the same process. We report the first series of 8 patients with recurrent infection-type stones likely to have been caused by a "hard to grow" organism. Five patients never had a positive culture; in 2 patients 1 of 10 urine cultures grew a coagulase-negative Staphylococcus and in 1 patient the same organism was grown from a stone but never in the urine. The clinical course of all of these patients was significantly improved after blind treatment with antibiotics and in one case with an anti-urease agent.  相似文献   
27.
In recent years there has been a marked increase in interest and publications dealing with violence in psychiatric facilities. There is general agreement that the increase in violent behavior is real despite underreporting prior to the late 1970s. The author proposes that the changes in structure and functioning of psychiatric facilities following the Community Mental Health Act of 1963 may be one of the factors responsible for the increase of violent behavior. To test this proposal, Index Medicus was searched for articles on violence in psychiatric facilities from 1935 through 1988. The first articles appeared in 1968. A review of leading textbooks of psychiatry during the same period revealed similar findings. The role of the lax milieu is discussed. It is proposed that the "medical model" as described in this paper be reinstituted in short-stay psychiatric facilities.  相似文献   
28.
Timing of onset of antidepressant response with fluoxetine treatment   总被引:6,自引:0,他引:6  
OBJECTIVE: The purpose of this study was to assess the time until onset of antidepressant response with fluoxetine treatment. METHOD: The authors evaluated 182 outpatients with major depression who had a sustained acute response to fluoxetine treatment. The outpatients received 8 weeks of treatment with 20 mg/day of fluoxetine and were assessed biweekly with the 17-item Hamilton Depression Rating Scale. The onset of response was defined as a 30% decrease in score on the Hamilton depression scale that persisted and led to a 50% decrease by week 8. The Kaplan-Meier product limit and Cox regression analysis were used to model the relationship between relevant variables and time until onset of response. RESULTS: The authors found that at weeks 2, 4, and 6, the probabilities of having an onset of response (for responders) were 55.5%, 24.7%, and 9.3%, respectively. The cumulative probabilities of onset of response at each time point were 55.5%, 80.2%, and 89.5%. Neither demographics nor clinical characteristics of depression predicted time until initial response. CONCLUSIONS: These data suggest that more than half of eventual responders to fluoxetine treatment at 8 weeks start to respond by week 2; over 75% start to respond by week 4. Conversely, the lack of onset of response at 4-6 weeks was associated with about a 73%-88% chance that patients would not have an onset of response by 8 weeks.  相似文献   
29.
30.
INTRODUCTION: Surgical treatment of third nerve palsy, sensory exotropia and strabismus secondary to anomalous innervation of the rectus muscles, frequently require large rectus muscle recessions in an attempt to maintain alignment in the primary position and reduce the effects of misinnervation. The aim of this study was to describe and evaluate the results of inactivation of a rectus muscle by its attachment to the adjacent orbital wall. METHODS: Seven subjects diagnosed with third-nerve palsy (three cases), Duane syndrome (two cases), sensory exotropia (one case), and congenital aberrant innervation of vertical rectus muscles (one case) underwent rectus muscle inactivation by orbital wall fixation. The rectus muscle was disinserted from the globe and reattached to the adjacent orbital periosteum using non-absorbable sutures. This surgery was performed on the lateral rectus muscle in six subjects, and surgery was performed on both ipsilateral vertical rectus muscles in one. RESULTS: Postoperatively four of six patients were aligned within 12 prism diopters of orthotropia in primary position. All patients had improvement of the anomalous head posture. In Duane syndrome, lateral rectus inactivation markedly reduced co-contraction and globe retraction. No overcorrections resulted. CONCLUSION: A rectus muscle may be functionally inactivated when its insertion is attached to the orbital periosteum. Advantages of this procedure over extirpation and free tenotomy include permanent disinsertion of the muscle from globe and reversibility.  相似文献   
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