全文获取类型
收费全文 | 26158篇 |
免费 | 1264篇 |
国内免费 | 178篇 |
专业分类
耳鼻咽喉 | 201篇 |
儿科学 | 577篇 |
妇产科学 | 439篇 |
基础医学 | 2869篇 |
口腔科学 | 619篇 |
临床医学 | 2089篇 |
内科学 | 6821篇 |
皮肤病学 | 491篇 |
神经病学 | 3039篇 |
特种医学 | 810篇 |
外科学 | 3927篇 |
综合类 | 44篇 |
一般理论 | 5篇 |
预防医学 | 1100篇 |
眼科学 | 451篇 |
药学 | 1468篇 |
中国医学 | 30篇 |
肿瘤学 | 2620篇 |
出版年
2024年 | 26篇 |
2023年 | 174篇 |
2022年 | 395篇 |
2021年 | 752篇 |
2020年 | 447篇 |
2019年 | 624篇 |
2018年 | 699篇 |
2017年 | 555篇 |
2016年 | 624篇 |
2015年 | 697篇 |
2014年 | 1017篇 |
2013年 | 1278篇 |
2012年 | 2012篇 |
2011年 | 2007篇 |
2010年 | 1166篇 |
2009年 | 1077篇 |
2008年 | 1761篇 |
2007年 | 1810篇 |
2006年 | 1682篇 |
2005年 | 1653篇 |
2004年 | 1637篇 |
2003年 | 1372篇 |
2002年 | 1327篇 |
2001年 | 205篇 |
2000年 | 133篇 |
1999年 | 164篇 |
1998年 | 256篇 |
1997年 | 221篇 |
1996年 | 200篇 |
1995年 | 175篇 |
1994年 | 135篇 |
1993年 | 132篇 |
1992年 | 119篇 |
1991年 | 99篇 |
1990年 | 93篇 |
1989年 | 78篇 |
1988年 | 71篇 |
1987年 | 76篇 |
1986年 | 61篇 |
1985年 | 60篇 |
1984年 | 87篇 |
1983年 | 45篇 |
1982年 | 52篇 |
1981年 | 46篇 |
1980年 | 36篇 |
1979年 | 22篇 |
1978年 | 23篇 |
1977年 | 38篇 |
1976年 | 20篇 |
1973年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Angela Favaro Tatiana Zanetti Elena Tenconi Daniela Degortes Andrea Ronzan Angela Veronese Paolo Santonastaso 《Eating disorders》2004,13(1):61-70
To date, few studies have examined the personality characteristics and clinical predictors of impulsive behaviors in eating disorders (ED). The aim of this work was to study the prevalence of a wide range of impulsive behaviors in a sample of 554 ED subjects and to examine the predictors of these behaviors. Subjects were diagnosed according to DSM-IV criteria as having anorexia nervosa restricting type (ANR; n = 183), anorexia nervosa binge eating/purging type (ANBP; n = 65), bulimia nervosa purging type (BNP; n = 244), and bulimia nervosa nonpurging type (BNNP; n = 62). Nine different types of impulsive behaviors were assessed in these groups. About 55% of the whole sample reported at least one type of impulsive behavior, 35% more than one, and about 13% more than three. According to findings, impulsive and multi-impulsive subjects are characterized by the presence of purging behavior and by specific temperamental features such as high levels of novelty seeking and low persistence. The prediction of impulsive behavior is further improved by considering the presence of a history of childhood abuse, maternal psychiatric morbidity, and some specific psychological symptoms such as maturity fears, perfectionism, depression, and obsessive-compulsive symptoms. The presence of impulsive behavior appears to be associated with overall higher levels of psychiatric symptomatology and eating psychopathology, thus indicating that they are an important feature to be considered in the assessment and treatment of ED. 相似文献
62.
63.
64.
Paolo R. Salvalaggio Katie Neighbors Susan Kelly Karan M. Emerick Kishore Iyer Riccardo A. Superina Peter F. Whitington Estella M. Alonso 《American journal of transplantation》2005,5(8):1868-1874
The Pediatric End-Stage Liver Disease (PELD) score was designed to reduce subjectivity in liver allocation and to advantage patients with a higher probability of waiting list mortality. The aims of this study were to determine the impact of PELD implementation for children with chronic liver disease and to assess whether PELD met its goal of standardization of liver allocation for children. This study used data reported to the United Network for Organ Sharing (UNOS) registry for children with chronic liver disease receiving primary cadaveric liver transplant between January 2000 and December 2001 (pre-PELD) and March 2002 and July 2003 (PELD). PELD reduced the percentage of children transplanted while in an intensive care unit and as status 1. A calculated PELD score was used for allocation in only 52% of recipients. Thirty percent were status 1 at transplant and PELD scores granted by exception were used for allocation in 18% of patients. There was regional variation in PELD score at allocation and use of exception scores with a significant relationship between PELD score and percentage of exception cases. Regional variation suggests that PELD has not resulted in standardization of listing practices in pediatric liver transplantation. 相似文献
65.
Paolo Calabresi Emesto Fedele Antonio Pisani Giovanni Fontana Nicola B. Mercuri Giorgio Bernardi Maurizio Raiteri 《The European journal of neuroscience》1995,7(9):1889-1894
Using a corticostriatal slice preparation, we have recently shown that tetanic stimulation of the corticostriatal pathway produces long-term depression (LTD) of striatal excitatory synaptic transmission. In the present study we have analysed the relationship between LTD and the striatal release of different endogenous transmitters. Samples of perfusate were collected via a small cannula placed just above the surface of the striatal slice close to the recording electrode, and were analysed by HPLC. The high-frequency stimulation (100 Hz, three trains, 3 s duration, 20 s intervals) used to induce LTD caused a significant but transient increase in the release of both excitatory (aspartate and glutamate) and inhibitory (glycine and GABA) amino acid transmitters. Tetanic stimulation also produced a significant, but transient increase in the release of endogenous dopamine. We conclude that the tetanic stimulation of the corticostriatal pathway is able to induce a large but transient release of excitatory amino acids and of dopamine, whose participation in the induction of striatal LTD has been demonstrated previously. Moreover, the maintenance of this form of synaptic plasticity does not seem to require a sustained change in transmitter release. 相似文献
66.
Vittorio Petraccone Finizia Auriemma Francesco Dal Poggetto Claudio De Rosa Gaetano Guerra Paolo Corradini 《Macromolecular chemistry and physics.》1993,194(5):1335-1345
In this contribution, the X-ray diffraction (XRD) pattern of a highly oriented sample of syndiotactic polystyrene in the mesomorphic form, collected by an automatic diffractometer, is presented, thus providing quantitative and more complete information relative to the diffracted intensity. The structural changes induced by annealing procedures in mesomorphic samples are shown through the analysis of the XRD patterns: both unoriented and oriented mesomorphic samples are transformed gradually into α-form crystals. On the basis of these evidences and of preliminary comparisons between the calculated Fourier transform of simplified models and the experimental diffraction intensity, it is suggested that the local organization in triplets of trans-planar chains, typical of the different modifications of the α-form, would be largely present also in the disordered chain agglomerates of the mesomorphic form. 相似文献
67.
68.
Onelio Geatti Brahm Shapiro Pier Giuseppe Orsolon Gianni Proto Ugo Paolo Guerra Francesco Antonucci Daniele Gasparini 《European journal of nuclear medicine and molecular imaging》1994,21(1):17-22
Technetium-99m methoxyisobutylisonitrile (MIBI), like thallium-201, has recently been introduced as a myocardial perfusion agent and is now also showing very promising results in parathyroid scintigrapy. The results of 201Tl/99mTc-pertechnetate and 99mTc-MIBI/99mTc-pertechnetate subtraction scintigraphy, ultrasonography and computed tomography are presented in a series of 43 patients operated on for hyperparathyroidism. All four imaging modalities were confirmed to be reliable, scintigraphy being the most accurate. Sensitivities ranged from 81% to 95%, that of 99mTc-MIBI being the highest. Moreover this tracer, which has more favourable physical and also biochemical properties, yielded images of superior quality. This allowed localization of the lesion by visual inspection only in as many as 86% of the patients with positive 99mTc-MIBI/99mTc-pertechnetate subtraction scintigraphy. We believe that the higher sensitivity, superior image quality and lower cost of 99mTc-MIBI imaging will make 99mTc-MIBI the new radiopharmaceutical of choice for parathyroid scintigraphy (when one takes into account the stability of labelling with large activities it is possible to perform three or four cardiac studies together with one parathyroid scintigraphic examination using one lyophililzed vial). 相似文献
69.
Francesco Franceschi Umile Giuseppe Longo Laura Ruzzini Paolo Simoni Bruno Beomonte Zobel Vincenzo Denaro 《Knee surgery, sports traumatology, arthroscopy》2007,15(3):266-268
Bilateral discoid medial menisci is an extremely rare condition of the knee and it can be associated to other pathological
findings, including anterior portion cyst formation. We report on the clinical features, radiographic findings, treatment
and results of one patient who presented a bilateral medial discoid meniscus combined with posterior portion cyst of the left
knee. To the best of the author’s knowledge, this is the first case of bilateral medial discoid meniscus associated with posterior
portion cyst formation. 相似文献
70.
Marina Quartu Maria Pina Serra Annalisa Manca Paolo Follesa Maria Letizia Lai Marina Del Fiacco 《International journal of developmental neuroscience》2003,21(1):23-33
The immunohistochemical occurrence of the neurotrophin (NT) proteins nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-4 (NT-4), and neurotrophin-3 (NT-3) is shown in the pre-term newborn, infant, and adult human post-mortem cerebellum. The NT-like immunoreactive structures were unevenly distributed and showed regional differences among cerebellar lobules and folia. NGF-, NT-4-, and NT-3-positive neuronal perikarya were observed in all specimens examined. At variance with the other neurotrophins, the BDNF antiserum labelled neuronal cell bodies only in newborn life and infancy, as well as extensive nerve fibre systems, whose density increased with age. The NT-antibodies, tested by Western blot on human cerebellum homogenates, revealed immunoreactive bands corresponding to proteins of heterogenous molecular weight. The results obtained provide a first demonstration of the tissue localization of the NTs in the human cerebellum from perinatal to adult age, thus suggesting their involvement in the development, differentiation and maintenance of the cerebellar connectivity. Codistribution of the four NTs or sets of them was observed in cortical and deep nuclei neurons. Multiple trophic roles for NTs, encompassing the classic target-derived and local mechanisms of support, are envisaged as significant in development, differentiation, and maintenance of the human cerebellar connectivity. 相似文献