全文获取类型
收费全文 | 24668篇 |
免费 | 2364篇 |
国内免费 | 419篇 |
专业分类
耳鼻咽喉 | 71篇 |
儿科学 | 521篇 |
妇产科学 | 500篇 |
基础医学 | 2305篇 |
口腔科学 | 123篇 |
临床医学 | 3579篇 |
内科学 | 1859篇 |
皮肤病学 | 109篇 |
神经病学 | 8650篇 |
特种医学 | 177篇 |
外科学 | 907篇 |
综合类 | 2525篇 |
现状与发展 | 2篇 |
一般理论 | 4篇 |
预防医学 | 1717篇 |
眼科学 | 60篇 |
药学 | 2153篇 |
30篇 | |
中国医学 | 1491篇 |
肿瘤学 | 668篇 |
出版年
2024年 | 131篇 |
2023年 | 520篇 |
2022年 | 709篇 |
2021年 | 1092篇 |
2020年 | 1152篇 |
2019年 | 1067篇 |
2018年 | 1032篇 |
2017年 | 1115篇 |
2016年 | 1149篇 |
2015年 | 1005篇 |
2014年 | 1533篇 |
2013年 | 2269篇 |
2012年 | 1392篇 |
2011年 | 1410篇 |
2010年 | 1256篇 |
2009年 | 1196篇 |
2008年 | 1172篇 |
2007年 | 1138篇 |
2006年 | 995篇 |
2005年 | 843篇 |
2004年 | 670篇 |
2003年 | 634篇 |
2002年 | 546篇 |
2001年 | 421篇 |
2000年 | 296篇 |
1999年 | 223篇 |
1998年 | 231篇 |
1997年 | 257篇 |
1996年 | 174篇 |
1995年 | 163篇 |
1994年 | 171篇 |
1993年 | 131篇 |
1992年 | 148篇 |
1991年 | 119篇 |
1990年 | 101篇 |
1989年 | 118篇 |
1988年 | 107篇 |
1987年 | 116篇 |
1986年 | 93篇 |
1985年 | 115篇 |
1984年 | 83篇 |
1983年 | 62篇 |
1982年 | 64篇 |
1981年 | 50篇 |
1980年 | 43篇 |
1979年 | 32篇 |
1978年 | 22篇 |
1977年 | 25篇 |
1976年 | 18篇 |
1975年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Qiang Fu Karestan C Koenen Mark W Miller Andrew C Heath Kathleen K Bucholz Michael J Lyons Seth A Eisen William R True Jack Goldberg Ming T Tsuang 《Neuropsychopharmacology》2007,62(10):1088-1094
BACKGROUND: Epidemiologic studies reveal that posttraumatic stress disorder (PTSD) is highly comorbid with both conduct disorder and major depression in men. The genetic and environmental etiology of this comorbidity has not been examined. METHODS: Data were analyzed from 6744 middle-aged male-male monozygotic and dizygotic twins from the Vietnam Era Twin Registry. Conduct disorder, major depression, and PTSD were assessed via telephone interview using the Diagnostic Interview Schedule for the DSM-III-R in 1992. Structural equation modeling was used to estimate additive genetic, shared environmental, and individual-specific environmental effects common and specific to conduct disorder, major depression, and PTSD. RESULTS: The association between conduct disorder and PTSD was explained primarily by common shared environmental influences; these explained 10% (95% confidence interval: 6%-17%) of the variance in PTSD. The association between major depression and PTSD was largely explained by common genetic influences; these explained 19% (95% confidence interval: 11%-26%) of the variance in PTSD. CONCLUSIONS: Our findings suggest that different etiologic mechanisms explain the association of conduct disorder and major depression with PTSD in male veterans. If replicated in other populations, results suggest research aimed at identifying specific genetic and environmental factors that influence PTSD may benefit from starting with those that have been more consistently and strongly associated with major depression and conduct disorder. 相似文献
52.
Marlon Normandin Joel Gagn Julie Bernard Robert lie Dom Miceli Michel Baudry Guy Massicotte 《Brain research》1996,730(1-2):40-46
Low-frequency stimulation is associated with long-term depression (LTD) of synaptic efficacy in various brain structures. Like long-term potentiation (LTP), homosynaptic LTD in area CA1 of the hippocampus appears to require NMDA receptor activation, changes in postsynaptic calcium concentration and phospholipase A2 (PLA2) activation. Arachidonic acid (AA) is released after the activation of calcium-dependent phospholipases and free AA is rapidly metabolized to a family of bioactive products (the eicosanoids) which are thought to be both intracellular and extracellular messengers. In the present study, we investigated the involvement of the cyclooxygenase and lipoxygenase pathways of AA metabolism in the formation of homosynaptic LTD in the rat hippocampus. Stimulation at 1 Hz for 15 min was used to produce homosynaptic depression in area CA1 of hippocampal slices. LTD induction was partially blocked by bromophenacyl bromide (50–100 μM), a selective PLA2 inhibitor, and by the a nonselective lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA; 100 μM). In contrast, the specific cyclooxygenase blocker indomethacin (100 μM) did not significantly reduce hippocampal LTD. Since NDGA interferes with LTD formation, we examined whether specific inhibitors of 5- and 12-lipoxygenases were capable of blocking LTD expression. The 12-lipoxygenase inhibitor baicalein at a concentration of 50 μM reduced LTP formation when given in the bath, an effect that was less pronounced with the 5-lipoxygenase inhibitor AA-861. These data suggest that the activation of endogenous PLA2 and the formation of 12-lipoxygenase metabolites of AA may be important factors controlling the expression of hippocampal LTD. 相似文献
53.
T. J. Taiminen S. Saarijrvi H. Helenius A. Keskinen T. Korpilahti R. K. R. Salokangas 《Acta psychiatrica Scandinavica》1996,94(3):185-186
The Depression Scale (DEPS), a new screening instrument for detecting depression in primary health care, was compared with the Hamilton Depression Scale (HDS) among 50 suicide attempters. Using the HDS as a gold standard, the positive and negative predictive values of the DEPS for the diagnosis of depression were 98% and 20%, respectively. The correlation between the total HDS scores and the total DEPS scores was 0.60. The DEPS may help general practitioners to detect depression among suicide attempters, but it should not be used to exclude depression. 相似文献
54.
Psychological factors influencing the surgical patients' consent to regional anaesthesia 总被引:2,自引:0,他引:2
M. N. PAPANIKOLAOU A. VOULGARI L. LYKOURAS Y. ARVANITIS G. N. CHRISTODOULOU A. DANOU–ROUSSAKI 《Acta anaesthesiologica Scandinavica》1994,38(6):607-611
To investigate the preoperative attitude of surgical patients to regional anaesthesia, 162 subjects scheduled for elective surgery were studied. On the day before operation, patients were interviewed by an anaesthesio–logist, using a semi–structured schedule. Topics investigated were sociodemographic variables and clinical correlates, such as past anaesthetic experience, information about anaesthesia and surgery, as well as questions and fears related to anaesthesia. Subjects were assessed for personality characteristics and emotional symptoms by Eysenck's Personality Questionnaire (EPQ), Zung's Self–rating Anxiety and Depression Rating Scales, Schalling–Sifneos' Personality Scale and the 43–item Life Events Inventory of Holmes and Rahe. Seventy–one patients (44%) consented to regional anaesthesia. Consent to regional anaesthesia was associated with advanced age, low neuroticism and high extroversion score in the EPQ, as well as longer duration of illness. The deniers of consent asked more questions and expressed more fears about anaesthesia. It is suggested that the patients' characteristics influence their preference, acceptance or refusal of regional anaesthesia. 相似文献
55.
Torrens House provides a short residential programme for families with a baby (8–12 months of age) identified by parents as having a sleep problem such as waking frequently at night and being difficult to settle. The programme involves the promotion of infant self-settling by the use of a controlled crying technique, together with wrapping, cessation of night feeds and establishment of a day-time routine. Twenty families (with 23 babies) were followed through the programme and for 3 months afterwards. There were significant decreases in the number of times the babies woke, the number of night-feeds and the length of time awake at night at 1 month follow-up, with a reduction in depressive symptomatology of the parents and a perceived improvement in their infants' behaviour. Twenty of the 23 babies were sleeping well at 3 month follow-up. 相似文献
56.
实验组为45名缓解的内源性抑郁症患(男25例,女20例)。对照组为15名缓解的双相障碍患者(男8例,女7例),71名正常人(男41例,女30例)。利用作者建立的想象结局法发现:实验组想象力总分显著低于正常人组,特别是当涉及不愉快事件的测题时,单项分亦显著低于正常人。双相障碍组总分亦显著低于正常人。实验组有关性内容的比率得分显著低于正常人。 相似文献
57.
Deep brain stimulation for Parkinson's disease dissociates mood and motor circuits: a functional MRI case study. 总被引:2,自引:0,他引:2
Taresa Stefurak David Mikulis Helen Mayberg Anthony E Lang Stephanie Hevenor Peter Pahapill Jean Saint-Cyr Andres Lozano 《Movement disorders》2003,18(12):1508-1516
Behavioral disturbances have been reported with subthalamic (STN) deep brain stimulation (DBS) treatment in Parkinson's disease (PD). We report correlative functional imaging (fMRI) of mood and motor responses induced by successive right and left DBS. A 36-year-old woman with medically refractory PD and a history of clinically remitted depression underwent uncomplicated implantation of bilateral STN DBS. High-frequency stimulation of the left electrode improved motor symptoms. Unexpectedly, right DBS alone elicited several reproducible episodes of acute depressive dysphoria. Structural and functional magnetic resonance imaging (fMRI) imaging was carried out with sequential individual electrode stimulation. The electrode on the left was within the inferior STN, whereas the right electrode was marginally superior and lateral to the intended STN target within the Fields of Forel/zona incerta. fMRI image analysis (Analysis of Functional NeuroImages, AFNI) contrasting OFF versus ON stimulation identified significant lateralized blood oxygen level-dependent (BOLD) signal changes with DBS (P < 0.001). Left DBS primarily showed changes in motor regions: increases in premotor and motor cortex, ventrolateral thalamus, putamen, and cerebellum as well as decreases in sensorimotor/supplementary motor cortex. Right DBS showed similar but less extensive change in motor regions. More prominent were the unique increases in superior prefrontal cortex, anterior cingulate (Brodmann's area [BA] 24), anterior thalamus, caudate, and brainstem, and marked widespread decreases in medial prefrontal cortex (BA 9/10). The mood disturbance resolved spontaneously in 4 weeks despite identical stimulation parameters. Transient depressive mood induced by subcortical DBS stimulation was correlated with changes in mesolimbic cortical structures. This case provides new evidence supporting cortical segregation of motor and nonmotor cortico-basal ganglionic systems that may converge in close proximity at the level of the STN and the adjacent white matter tracts (Fields of Forel/zona incerta). 相似文献
58.
T. V. Peker C. Pelin H. B. Turgut A. Anıl A. Sevim 《European archives of oto-rhino-laryngology》1998,255(8):391-395
Since it covers the lateral wall of the mastoid air system, the suprameatal triangle is of importance to otologic surgeons
during mastoidectomy. Because of this clinical importance, topographic anatomy of the suprameatal spine and depression was
studied on Anatolian skulls. In all, 363 male and 231 female skulls were studied. The most prevalent type of suprameatal spine
resembled a crest and was found in both sexes on the right (77.6%) and left (80%) sides. The absence of a suprameatal depression
was significantly higher in females (right 9.1%; left 8.7%) than in males (right 1.7%; left 2.5%). Suprameatal depressions
were mostly shallow in female subjects, but were mostly observed in males to be at a medium depth or deep.
Received: 5 January 1998 / Accepted: 19 March 1998 相似文献
59.
P M Ellis R Beeston C J McIntosh C E Salmond R R Cooke 《Acta psychiatrica Scandinavica》1992,86(2):108-112
Decreased binding of tritiated imipramine to platelets has been considered to be a potential biological marker of depression. However, it has been unclear how binding values alter during treatment and recovery. This study investigated imipramine binding parameters and depressive symptoms in 25 patients suffering from major depression at entry to the study and 1, 3 and 6 months later. Although the initial Bmax values were significantly lower in the depressed patients than in healthy subjects, it was not possible to establish a clear relationship between recovery from depression and Bmax. The power of this study to detect an effect of at least 10% of the variance in Bmax due to factors related to recovery from depression was 0.78. 相似文献
60.
Martin Orrell Robert Howard Andrew Payne Klaus Bergmann Robert Woods Brian S. Everitt Raymond Levy 《International journal of geriatric psychiatry》1992,7(4):263-275
One hundred and sixty-four patients admitted to a psychogeriatric unit were given a combination of four different cognitive tests: the Mini Mental State Examination (MMSE), the Abbreviated Mental Test Score, The Felix Post Unit Score and the compilation of tests recommended by the MRC Alzheimer's Disease Workshop. The tests were compared with respect to their ability to sort accurately cases of dementia and depression, and the effects of age and education on test score and misclassification rate with diagnosis controlled for. The MMSE had a very high misclassification rate for the poorly educated and depressed group. The logistical discriminant functional analysis selected only eight items as the best discriminators between organic/ functional or dementia/depression groups. Only one of these eight was not either a memory or orientation test. The value of simply adding up tests of different aspects of cognitive function in dementia assessment or screening is questioned. 相似文献