全文获取类型
收费全文 | 13042篇 |
免费 | 1875篇 |
国内免费 | 516篇 |
专业分类
耳鼻咽喉 | 138篇 |
儿科学 | 182篇 |
妇产科学 | 48篇 |
基础医学 | 1063篇 |
口腔科学 | 317篇 |
临床医学 | 1719篇 |
内科学 | 2167篇 |
皮肤病学 | 34篇 |
神经病学 | 4037篇 |
特种医学 | 701篇 |
外科学 | 1078篇 |
综合类 | 1231篇 |
预防医学 | 840篇 |
眼科学 | 151篇 |
药学 | 687篇 |
12篇 | |
中国医学 | 762篇 |
肿瘤学 | 266篇 |
出版年
2024年 | 84篇 |
2023年 | 386篇 |
2022年 | 639篇 |
2021年 | 901篇 |
2020年 | 775篇 |
2019年 | 728篇 |
2018年 | 609篇 |
2017年 | 702篇 |
2016年 | 698篇 |
2015年 | 640篇 |
2014年 | 941篇 |
2013年 | 1146篇 |
2012年 | 740篇 |
2011年 | 810篇 |
2010年 | 624篇 |
2009年 | 595篇 |
2008年 | 510篇 |
2007年 | 554篇 |
2006年 | 483篇 |
2005年 | 393篇 |
2004年 | 378篇 |
2003年 | 342篇 |
2002年 | 316篇 |
2001年 | 232篇 |
2000年 | 148篇 |
1999年 | 114篇 |
1998年 | 163篇 |
1997年 | 124篇 |
1996年 | 114篇 |
1995年 | 74篇 |
1994年 | 80篇 |
1993年 | 44篇 |
1992年 | 46篇 |
1991年 | 38篇 |
1990年 | 24篇 |
1989年 | 29篇 |
1988年 | 25篇 |
1987年 | 21篇 |
1986年 | 28篇 |
1985年 | 21篇 |
1984年 | 15篇 |
1983年 | 18篇 |
1982年 | 16篇 |
1981年 | 13篇 |
1980年 | 13篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1974年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
111.
Jonas G. Miller Mahnoor Hyat Susan B. Perlman Ronald J. Wong Gary M. Shaw David K. Stevenson Ian H. Gotlib 《Developmental psychobiology》2023,65(1):e22351
Exposure to adversity is a well-documented risk factor for cognitive, behavioral, and mental health problems. In fact, the consequences of adversity may be intergenerational. A growing body of research suggests that maternal exposures to adversity, including those prior to childbirth, are associated with offspring biobehavioral development. In a sample of 36 mothers and their preschool-age children (mean child age = 4.21 ± 0.92 years), we used functional near-infrared spectroscopy to replicate and extend this work to include brain activation during inhibitory control in young children. We found that measures of maternal exposure to adversity, including cumulative, childhood, and preconception exposures, were significantly and positively associated with activation in the right frontopolar prefrontal cortex (PFC) and in the left temporal and parietal clusters during inhibitory control. In addition, and consistent with previous findings, children's increased negative affect and decreased effortful control were associated with increased right PFC activation during inhibitory control. These findings provide preliminary evidence that maternal and dispositional risk factors are linked to alterations in PFC functioning during the preschool years. Children of mothers with a history of exposure to adversity, as well as children who are less temperamentally regulated, may require increased neural resources to meet the cognitive demands of inhibitory control. 相似文献
112.
目的 探讨绝经后阴道出血的病因。方法 分析242例绝经后阴道出血并行诊断性乔宫的临床和病理资料。结果 绝经后阴道出血的主要病理诊断分另是功能性子宫内膜(60.73%)、炎症(28.92%)和恶性肿瘤(10.35%)。结论 内分泌紊乱性疾病是绝经后出血的常见病因,年老妇女恶性肿瘤发生率高。 相似文献
113.
功能性消化不良患者胃膨胀感知的改变 总被引:3,自引:0,他引:3
目的研究功能性消化不良(FD)患者胃膨胀感知的改变。方法应用灌注导管测压仪研究了7例FD患者、5例FD并心理异常患者及5例正常人胃对容量刺激的感觉。结果发现FD患者胃对容量刺激的最低敏感性阈值、不适阈值及疼痛阈值分别为(195.7±65.3),(304.3±58.6),(464.3±47.2)ml,FD并心理异常患者为(123.0±40.3),(254.0±49.8),(466.0±76.4)ml,均明显低于正常人的(327.0±44.7),(532.4 ±107.4),(678.0±117.4)ml(P<0.01);三者的胃顺应性无明显改变。结论胃对容量刺激的感知过度敏感是FD发病的机制之一。 相似文献
114.
115.
Gregory McCarthy Mark Spicer Anthony Adrignolo Marie Luby John Gore Truett Allison 《Human brain mapping》1994,2(4):234-243
Localized brain activation in response to moving visual stimuli was studied by functional magnetic resonance imaging (fMRI). Stimuli were 100 small white dots randomly arranged on a visual display. During the Motion condition, the dots moved along random, noncoherent linear trajectories at different velocities. During the Blink condition, the dots remained stationary but blinked on and off every 500 ms. The Motion and Blink conditions continuously alternated with 10 cycles per run and 6–8 runs per experiment. In half of the runs, the starting stimulus condition was Motion, while in the remaining runs it was Blink. A series of 128 gradient echo echoplanar images were acquired from 5–7 slices during each run using a 1.5 T GE Signa with an Advanced NMR echoplanar subsystem. The time series for each voxel were analyzed in the frequency domain. Voxels which demonstrated a significant spectral peak at the alternation frequency and whose phase changed in response to stimulus order were considered activated. These activated voxels were displayed upon high resolution anatomical images to determine the sites of activation and were also transformed into the coordinates of Talairach and Tournoux ([1988] Co-planar Stereotaxic Atlas of the Human Brain, New York: Thieme) for comparison to prior neuroimaging studies. Seven of ten subjects showed clusters of activation bilaterally at the junction of the temporal and occipital lobes (area 37) in response to moving stimuli. Most activated voxels were located within or adjacent to a region designated the parietal-temporal-occipital fossa, or PTOF. Five subjects also showed activation to moving stimuli in midline occipital cortex. The activated voxels in midline cortex had a significantly shorter phase delay in their MR signal change relative to voxels in PTOF. © 1995 Wiley-Liss, Inc. 1 1 This article is a US Government work and, as such, is in the public domain in the United States of America 相似文献
116.
Intra-Operative Direct Electrical Stimulations of the Central Nervous System: The Salpêtrière Experience With 60 Patients 总被引:6,自引:0,他引:6
Duffau H Capelle L Sichez J Faillot T Abdennour L Law Koune JD Dadoun S Bitar A Arthuis F Van Effenterre R Fohanno D 《Acta neurochirurgica》1999,141(11):1157-1167
Indications of surgical treatment for lesions in the central nervous system depend on the risk of a definitive neurological deficit, related to the benefit of resection. Detection of eloquent areas is then necessary because of major individual variability. Neuro-imaging functional techniques are in development and are beginning to be efficient for cortical sensorymotor mapping, but still lack sensitivity and specificity for language mapping, and remain unable to give real-time data during surgery and to perform sub-cortical mapping. The more precise and reliable method of functional mapping is represented by the intra-operative direct electrical stimulations (DES), which allow identification and preservation of essential pathways for motricity, sensibility and language, at each level of the central nervous system (cortico-subcortical). We report our experience of DES in the surgery of tumours and vascular malformations located in supra-tentorial brain eloquent areas, with a consecutive series of 60 patients operated on under general or local anaesthesia, from November 1996 until May 1999 in our department at La Salpêtrière Hospital. Presenting symptoms in the 60 subjects (39 males, 21 females, mean age: 45 years) were seizures in 37 cases with normal clinical examination, and mild neurological deficit in 29 cases. MRI showed 60 supra-tentorial brain lesions: 30 precentral, 12 postcentral, 14 perisylvian in the dominant hemisphere, 4 deep-seated. All subjects underwent surgical resection using DES, with supratentorial cortico-subcortical mapping under general anaesthesia for motor areas detection in 43 cases and under local anaesthesia for sensori-motor and/or language tasks in 17 cases. The final histological diagnosis was 44 gliomas (31 low-grade and 13 high-grade), 9 metastasis, 3 cavernomas, 4 arteriovenous malformations (AVM). Resection was total or subtotal in 52 cases (87%) and partial in 8 cases (13%). 29 patients had no post-operative deficit, while the other 31 patients were impaired post-operatively, with in all cases, except 3, a complete recovery delayed for 15 days to 3 months (overall morbidity: 5%). The median follow up was 14 months. Intra-operative direct electrical stimulations of the central nervous system constitute a reliable, precise and safe method, allowing the realization of a functional mapping useful for all operations of lesions located in eloquent areas. This technique allows a minimization of definitive post-operative neurological deficit, and concurrently an improvement in the quality of resection. 相似文献
117.
The aim of the study was to assess pelvic floor function and dysfunction using intravaginal devices (IVD test). One hundred and eighty-five patients were evaluated, 65 (35.1%) in the control group without genital prolapse and 120 (64.9%) in the study group, with prolapse. Anatomic changes were evaluated on a scale described by Halban, and functional classification based on palpation of the muscles of the pelvic floor during contraction. Additionally, weighted vaginal devices were used to assess pelvic floor function. Statistic analysis was performed with the Spearman-Pearson correlation coefficient, the 2 test and the response/ operator characteristic curve. There was an acceptable correlation between the IVD test and the functional classification of 0.75. Using this classification, the IVD test showed 86.58% sensitivity, 75.72% specificity, and had a positive predictive value 73.95% and a negative predictive value of 87.64%. Significant differences between pelvic floor muscle activity in those patients with and without genital prolapse were observed (X2=58.28, P=<0.005). It was concluded that pelvic floor assessment can be done through the evaluation of active muscle strength or pelvic floor integrity using the functional classification and the IVD test.EDITORIAL COMMENT: In 1988, Peattie and Plevnick introduced the use of weighted vaginal cones to exercise the pelvic floor muscles and treat stress urinary incontinence [1]. Contreras-Ortiz and Nuñez build on this earlier work, using a similar technique to assess pelvic floor muscle function and integrity. Specifically, pelvic floor function is assessed by a combination of digital palpation of the pubococcygeus muscle at rest and during contraction; pelvic floor integrity is assessed by the patient's ability to retain a weighted cone vaginally for 1 minute. Scoring of these two parameters can then be objectively followed for therapeutic response to treatment for urinary incontinence or pelvic relaxation. Many of us forget to palpate the pubococcygeus muscle at rest and during an elicited contraction during baseline or follow-up examination. As this study indicates, simple assessment of pelvic floor function and integrity is possible, and should be used both clinically and in research. 相似文献
118.
Regina K. Kinney Robert J. Gatchel Peter B. Polatin Tom G. Mayer 《Journal of occupational rehabilitation》1991,1(3):235-243
The functional restoration approach to treating chronic spinal disability consists of a medically directed, interdisciplinary team approach to physical reconditioning and a cognitive-behavioral crisis intervention procedure for dealing with related psychosocial problems. One- and two-year follow-up studies have demonstrated the clinical efficacy of this approach. The present article describes this approach and summarizes the research documenting its success in treating patients with chronic spinal disability. This article also highlights the pitfalls in misunderstanding and misrepresenting the components of the functional restoration approach when evaluating treatment efficacy. 相似文献
119.
W.T. Ivan Yeung Ting-Yim Lee Rolando F. Del Maestro Roman Kozak Thomas Brown 《Journal of neuro-oncology》1992,14(2):177-187
Summary We have developed an in vivo method of measuring the blood-brain transfer constant (K) of iopamidol and the cerebral plasma volume (Vp) in brain tumors using a clinical X-ray CT scanner. In patient studies, Isovue 300 (iopamidol) was injected at a dosage of 1 ml/kg patient body weight. Serial CT scans of the tumor site and arterial blood samples from a radial artery were taken up to 48 min after injection. The leakage of iopamidol into the brain through the blood-brain barrier was modelled as an exchange process between two compartments, the intravascular plasma space and the tissue interstitial space. Using this model and the concentration measurements in blood plasma and tissue, quantitative estimates of K and Vp in brain tumors were obtained. In addition, distribution of the estimated values of K and Vp in tumors were displayed as false colour functional images overlaid on the conventional CT scan.In a study of twelve patients with anaplastic astrocytoma (n = 3), glioblastoma multiforme (n = 4) or metastases (n = 5) the mean K and VP values in tumor were found to be 0.0273 ± 0.0060 ml/min/g and 0.068 ± 0.11 ml/g respectively. These values were significantly higher than those in grey or white matter in the contralateral normal hemisphere (p < 0.05). The functional images showed variations in K and Vp within the tumor which were difficult to perceive in the original contrast enhanced CT scans. 相似文献
120.
Cortical activation during retrieval of arithmetical facts and actual calculation: a functional magnetic resonance imaging study 总被引:5,自引:0,他引:5
By using functional magnetic resonance imaging (fMRI), the neural substrates involved in mental recitation of the single-digit multiplication table and serial subtraction were studied. The former depends mostly on well-learned arithmetical facts, while the latter requires arithmetic processing. Activation during each task was compared with that in a number counting control. During the recitation of single-digit multiplication, the activated regions included the area lying along the left intraparietal sulcus, the premotor and supplementary motor areas, and the posterior portion of the left inferior frontal gyrus. The areas activated during serial subtraction included these areas as well as the bilateral prefrontal and right parietal areas. From the results obtained during retrieval of the multiplication table in this study and previous studies, it was concluded that semantic memory of the multiplication table is stored in the area lying along the intraparietal sulcus and that the frontal areas play an executive role in utilizing the semantic memory of arithmetical facts. It was assumed that the arithmetical facts requiring actual calculation are also stored in the same region. The additional activation during serial subtraction compared with the activation during retrieval of the multiplication table is probably due to the processes of actual calculation. These processes include proper alignment of digits, which may have caused the right parietal activation, and maintaining digits needed for the mental serial subtractions, which may have caused the bilateral prefrontal activation. 相似文献