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   1671篇
  免费   99篇
  国内免费   7篇
耳鼻咽喉   3篇
儿科学   22篇
妇产科学   95篇
基础医学   239篇
口腔科学   123篇
临床医学   105篇
内科学   376篇
皮肤病学   6篇
神经病学   340篇
特种医学   58篇
外科学   120篇
综合类   3篇
预防医学   89篇
眼科学   38篇
药学   77篇
中国医学   1篇
肿瘤学   82篇
  2023年   10篇
  2022年   23篇
  2021年   45篇
  2020年   29篇
  2019年   45篇
  2018年   30篇
  2017年   30篇
  2016年   44篇
  2015年   45篇
  2014年   57篇
  2013年   73篇
  2012年   147篇
  2011年   107篇
  2010年   66篇
  2009年   73篇
  2008年   131篇
  2007年   107篇
  2006年   100篇
  2005年   115篇
  2004年   95篇
  2003年   93篇
  2002年   79篇
  2001年   17篇
  2000年   12篇
  1999年   17篇
  1998年   22篇
  1997年   13篇
  1996年   11篇
  1995年   15篇
  1994年   10篇
  1993年   8篇
  1992年   8篇
  1991年   9篇
  1990年   5篇
  1989年   4篇
  1988年   11篇
  1987年   7篇
  1986年   8篇
  1985年   4篇
  1983年   3篇
  1982年   3篇
  1981年   4篇
  1980年   7篇
  1979年   11篇
  1978年   7篇
  1977年   3篇
  1976年   5篇
  1975年   3篇
  1972年   2篇
  1939年   1篇
排序方式: 共有1777条查询结果,搜索用时 15 毫秒
1.

Background  

Anterior cruciate ligament (ACL) injury or reconstruction can cause knee impairments and disability. Knee impairments are related to quadriceps performance – accelerated reaction time (ART) – and disability to performance of daily living activities which is assessed by questionnaires such as the Lysholm knee score. The purposes of this study were to investigate the effect of cross exercise, as supplementary rehabilitation to the early phase of ACL reconstruction: a) on quadriceps ART at the angles 45°, 60° and 90° of knee flexion and, b) on the subjective scores of disability in ACL reconstructed patients.  相似文献   
2.
Summary This paper reports on the regional prevalence of symptoms of depression and clinical depression (current major depressive episodes) in Greence in the years 1978 and 1984. Prevalence rates were estimated from two extensive, nationwide cross-sectional home surveys on psychosocial issues and health, carried out in four geographical areas: the Greater Athens area, the Greater Thessaloniki area, the rest of the urban areas and rural areas. The methodology used, the sampling procedure and the screening instrument (The Center for Epidemiologic Studies-Depression Scale) were the same in both surveys. Within the 6-year period a substantial increase in the prevalence of symptoms of depression in all geographic areas was observed, with the Athenian respondents expressing a higher number of symptoms of depression than their counterparts from the other areas. The prevalence of current major depressive episodes, according to specific criteria matched with criteria from the DSM III R, was increased in 1984 in Athens and in the rural areas only. We suggest that economic instability between 1978 and 1984 probably contributed to the changes in the rates of depressive disorders.  相似文献   
3.
Neuron-enriched cultures derived from 6-day-old chick embryo cerebral hemispheres were treated with morphine or methadone, 10(-5) M or 10(-6) M, on days 4-6 or 6-8 in culture and were evaluated morphologically and biochemically at day 9 using phase contrast microscopy and choline acetyltransferase activity (ChAT) as a cholinergic marker. The treatment of the cultures with morphine markedly affected their growth pattern; specifically, we observed an increased number of flat cells presumptively glia, and aggregates sided by flat cells and devoid of thick bundles of neuritic processes that normally characterize neuron-enriched cultures. These morphologic changes were reflected in a drastic decrease of ChAT activity in cultures treated from day 4 to day 6 but not from 6 to 8. In contrast to morphine, exposure to 10(-6) M methadone from day 4 to day 6 resulted in reduced ChAT activity but the growth pattern of the cultures remained morphologically intact. We suggest that morphine exerts a general neurotoxic effect whereas methadone may affect some specific cholinergic function.  相似文献   
4.
Thyroid stimulating hormone (TSH) and prolactin (PRL) plasma levels were studied during electroconvulsive therapy (ECT) in five schizophrenic patients in a simulated ECT (SECT) controlled experimental design. The data were compared to those obtained from a group of 10 depressed patients treated with ECT. In the schizophrenic group, both PRL and TSH increased significantly during ECT compared to SECT, as they did in the depressive group during ECT. Thus, the hormonal TSH and PRL profile during ECT is similar in schizophrenia and depression. It is concluded that the changes in TSH and PRL induced by ECT are specifically linked to the current or the seizure, and are not related to the type of psychopathology.  相似文献   
5.
Neuropsychological findings from investigation of 46 HIV-seropositive asymptomatic and 14 HIV-seropositive symptomatic haemophiliacs without AIDS-related complex (ARC) or AIDS, with known duration of HIV seropositivity were compared with 29 seronegative controls. Subjects were assessed blindly using a battery of sensitive computerized neuropsychological tests. They underwent a thorough neurological examination, were assessed for mood and screened for psychopathology. Symptomatic HIV-positive haemophiliacs without ARC or AIDS showed statistically significant decreased performances compared with HIV-negatives in choice reaction, visuomotor coordination and global attentional performance (P = 0.018, 0.039 and 0.044, respectively). HIV-positive asymptomatic subjects gave lower performances than HIV-negative subjects in all tests, although these differences were not statistically significant. However, there was a statistically significant trend for these findings between seronegative, asymptomatic and symptomatic groups. Impairment was not associated with mood factors. Duration of seropositivity was found to be a more important factor than Centers for Disease Control stage in the choice reaction test (P less than 0.01). These findings indicate that mild cognitive impairment observed during the natural history of HIV infection in haemophiliacs without ARC or AIDS may be a progressive phenomenon not necessarily associated with the clinical expression of HIV infection.  相似文献   
6.
BACKGROUND AND PURPOSE: Helical tomotherapy can eliminate the need for junction lines. The goal of this study is to evaluate tomotherapy in the delivery of CSA radiation and measurement of plan quality using physical parameters in comparing conventional (CSA-RT) and helical tomotherapy (CSA-TOMO) plans. PATIENTS AND METHODS: CSA-TOMO and CSA-RT plans were created for dosimetric comparison. Integral dose values were calculated. The ratios D50% (dose received by 50% of the organ at risk's volume) and D10% (dose received by 10% of the organ at risk's volume) were calculated representing large volumes and small volumes of organs at risk receiving significant dose. RESULTS: When considering D50% and D10%, CSA-TOMO has a dosimetric advantage over CSA-RT for most organs at risk. The body integral dose was higher for the CSA-TOMO plan by approximately 6.5%. CONCLUSIONS: Tomotherapy is a feasible alternative for treatment of CSA. Analysis shows that tomotherapy improves dose ratios over conventional radiation for most organs at risk. The impact of a small increase in whole body integral dose is unknown. Long-term follow-up will be needed to answer this question as others have argued of the possibility of increased risk of secondary malignancies due to delivery of radiotherapy with IMRT.  相似文献   
7.
BACKGROUND: Limited knowledge exists regarding the neurobiology of trichotillomania (TTM). Cerebellum (CBM) volumes were explored, given its role in complex, coordinated motor sequences. METHODS: Morphometric magnetic resonance imaging (MRI) scans were obtained for 14 female subjects with DSM-IV diagnoses of TTM and 12 age-, education-, and gender-matched normal control (NC) participants. Parcellation was performed utilizing a recently developed methodology to measure subterritory volumes of the CBM. Regions were defined based on knowledge of the structural and functional subunits of the CBM. RESULTS: As predicted, significant group differences were reported for CBM raw cortical volumes (p = .008) that survived correction for total brain volume (TBV; p = .037) and head circumference (HC; p = .011). A priori and post hoc group raw volume comparisons for CBM subterritories and functional clusters revealed many significant differences. However, most differences failed to withstand correction for total CBM volumes (TCV). Smaller volumes were consistently reported for the TTM versus NC cohorts. Total Massachusetts General Hospital Hair Pulling Scale (MGHHPS) scores were significantly inversely correlated with left primary sensorimotor cluster volumes (p = .008), with smaller volumes associated with more severe TTM symptoms. CONCLUSIONS: These findings implicate the CBM in the neurobiology of TTM, with reduced subterritory volumes reported for the TTM versus NC groups.  相似文献   
8.
9.
10.
The chronic mentally ill in Greece are primarily cared for in large public mental hospitals or by their families because of the absence of community-based alternatives and the centralization of existing services in Athens and Thessaloniki. However, in the last decade new legislation to improve the lives of the chronically ill has been passed, additional day care facilities have been opened, and the development of decentralized mental health services has been scheduled by the National Health System. A case report illustrates the care provided at Greece's first community mental health center, established in 1979 in Athens.  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