全文获取类型
收费全文 | 5026篇 |
免费 | 218篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 75篇 |
儿科学 | 106篇 |
妇产科学 | 49篇 |
基础医学 | 575篇 |
口腔科学 | 55篇 |
临床医学 | 348篇 |
内科学 | 1324篇 |
皮肤病学 | 137篇 |
神经病学 | 322篇 |
特种医学 | 211篇 |
外科学 | 827篇 |
综合类 | 27篇 |
一般理论 | 1篇 |
预防医学 | 236篇 |
眼科学 | 97篇 |
药学 | 325篇 |
中国医学 | 16篇 |
肿瘤学 | 540篇 |
出版年
2023年 | 35篇 |
2022年 | 71篇 |
2021年 | 146篇 |
2020年 | 56篇 |
2019年 | 93篇 |
2018年 | 117篇 |
2017年 | 82篇 |
2016年 | 100篇 |
2015年 | 85篇 |
2014年 | 146篇 |
2013年 | 167篇 |
2012年 | 247篇 |
2011年 | 308篇 |
2010年 | 159篇 |
2009年 | 152篇 |
2008年 | 259篇 |
2007年 | 275篇 |
2006年 | 238篇 |
2005年 | 246篇 |
2004年 | 187篇 |
2003年 | 199篇 |
2002年 | 206篇 |
2001年 | 174篇 |
2000年 | 179篇 |
1999年 | 138篇 |
1998年 | 46篇 |
1997年 | 54篇 |
1996年 | 41篇 |
1995年 | 28篇 |
1994年 | 27篇 |
1993年 | 25篇 |
1992年 | 106篇 |
1991年 | 84篇 |
1990年 | 85篇 |
1989年 | 97篇 |
1988年 | 93篇 |
1987年 | 67篇 |
1986年 | 69篇 |
1985年 | 73篇 |
1984年 | 51篇 |
1983年 | 46篇 |
1982年 | 16篇 |
1981年 | 13篇 |
1979年 | 29篇 |
1978年 | 10篇 |
1977年 | 11篇 |
1976年 | 10篇 |
1975年 | 19篇 |
1973年 | 13篇 |
1968年 | 13篇 |
排序方式: 共有5271条查询结果,搜索用时 15 毫秒
41.
Masato Matsuda Mika Sato Hiroki Sakata Takahisa Ogawa Ken-ichiro Yamamoto Taiji Yakushiji Makoto Fukuda Takehiro Miyasaka Kiyotaka Sakai 《Journal of artificial organs》2008,11(3):148-155
When uremic blood flows through dialyzers during hemodialysis, dialysis membrane surfaces are exposed to shear stress and internal filtration, which may affect the surface characteristics of the dialysis membranes. In the present study, we evaluated changes in the characteristics of membrane surfaces caused by shear stress and internal filtration using blood substitutes: water purified by reverse osmosis and 6.7 wt% dextran70 solution. We focused on the levels of a hydrophilic modifier, polyvinylpyrrolidone (PVP), on the membrane surface measured by attenuated total reflectance Fourier transform infrared spectroscopy. Experiments involving 4 h dialysis, 0-144 h shear-stress loading, and 4 h dead-end filtration were performed using polyester-polymer alloy (PEPA) and polysulfone (PS) membranes. After the dialysis experiments with accompanying internal filtration, average PVP retention on the PEPA membrane surface was 93.7% in all areas, whereas that on the PS membrane surface was 98.9% in all areas. After the shear-stress loading experiments, PVP retention on the PEPA membrane surface decreased as shear-stress loading time and the magnitude of shear stress increased. However, with the PS membrane, PVP retention scarcely changed. After the dead-end filtration experiments, PVP retention decreased in all areas for both PEPA and PS membranes, but PVP retention on the PEPA membrane surface was lower than that on the PS membrane surface. PVP on the PEPA membrane surface was eluted by both shear stress and internal filtration, while that on the PS membrane surface was eluted only by internal filtration. 相似文献
42.
Neural mechanisms of three-dimensional vision 总被引:2,自引:0,他引:2
We can see things in three dimensions because the visual system re-constructs the three-dimensional (3D) configurations of objects from their two-dimensional (2D) images projected onto the retinas. The purpose of this paper is to give an overview of the psychological background and recent physiological findings concerning three-dimensional vision. Psychophysical and computational studies have suggested that in the visual system the 3D surface orientation is first estimated independently from individual depth cues--such as binocular disparity, as well as various monocular cues including texture gradients--and then the information from these different depth cues is integrated to construct a generalized representation of the 3D surface geometry. Neurons involved in low-level disparity processing, or the detection of local absolute disparity, were found mainly in the occipital cortex, whereas neurons involved in high-level disparity processing, or the reconstruction of 3D surface orientation through the computation of disparity gradients, were found mainly in the parietal area caudal intraparietal sulcus (CIP). Neurons sensitive to texture gradients, which is one of the major monocular cues, were also found in CIP. The majority of these neurons were sensitive to disparity gradients as well, suggesting their involvement in the computation of 3D surface orientation. In CIP, neurons sensitive to multiple depth cues were widely distributed together with those sensitive to a specific depth cue, suggesting CIP's involvement in the integration of depth information from different sources. In addition, human and monkey imaging studies have indicated convergence of multiple depth cues in CIP. These neurophysiological findings suggest that CIP plays a critical role in 3D vision by constructing a generalized representation of the 3D surface geometry of objects. 相似文献
43.
Nakajima-Takenaka C Sakata S Kato S Ohga Y Murata KY Taniguchi S Takaki M 《Experimental physiology》2005,90(4):635-644
We have previously reported that continuous infusion of dobutamine into the coronary artery induces positive inotropic effects but induces no detrimental effects in cross-circulated, excised normal rat hearts and even in Ca2+ overload-induced contractile failing rat hearts. However, we hypothesized that some detrimental effects on left ventricular (LV) function are induced after continuous dobutamine infusion and the following clearance of blood dobutamine, as is the case after beta-adrenergic receptor stimulation. To test this hypothesis, we investigated LV mechanical work and energetics in the same type of preparations that underwent continuous dobutamine infusion and clearance of blood dobutamine. We found that both mean end-systolic pressure and systolic pressure-volume area (PVA; a measure of total mechanical energy per beat) at midrange LV volume were significantly (P < 0.01) decreased. The mean myocardial oxygen consumption per beat intercept, which is composed of for the total Ca2+ handling in excitation-contraction coupling and basal metabolism, of the and PVA linear relation was also significantly (P < 0.05) decreased (n=8). The mean slope of the linear relation was unchanged in such hearts. Post-dobutamine basal metabolism was unchanged (n = 5 of the 8 hearts). The moderate proteolysis of a cytoskeleton protein, alpha-fodrin was identified (n = 7 of the 8 hearts with the decreased intercept), after clearance of blood dobutamine. In agreement with our hypothesis, the detrimental effect of the post-beta-adrenergic receptor stimulation was induced by a moderate concentration of dobutamine; we found systolic dysfunction due to the impairment of Ca2+ handling in excitation-contraction coupling in the rat LV and proteolysis of a cytoskeleton protein, alpha-fodrin. 相似文献
44.
Kabashima K Murata T Tanaka H Matsuoka T Sakata D Yoshida N Katagiri K Kinashi T Tanaka T Miyasaka M Nagai H Ushikubi F Narumiya S 《Nature immunology》2003,4(7):694-701
Physical interaction of T cells and dendritic cells (DCs) is essential for T cell proliferation and differentiation, but it has been unclear how this interaction is regulated physiologically. Here we show that DCs produce thromboxane A2 (TXA2), whereas naive T cells express the thromboxane receptor (TP). In vitro, a TP agonist enhances random cell movement (chemokinesis) of naive but not memory T cells, impairs DC-T cell adhesion, and inhibits DC-dependent proliferation of T cells. In vivo, immune responses to foreign antigens are enhanced in TP-deficient mice, which also develop marked lymphadenopathy with age. Similar immune responses were seen in wild-type mice treated with a TP antagonist during the sensitization period. Thus, TXA2-TP signaling modulates acquired immunity by negatively regulating DC-T cell interactions. 相似文献
45.
46.
Yoko Mamada Takahiro Murata Ayumi Taniguchi Yuki Hasegawa Tetsuomi Suzuki Kyoko Kohda Kiyoto Nasuno Toshiaki Watanabe Seiji Yamaguchi Akira Ishiguro 《Arerugī》2008,57(5):552-557
We reported a 4-month-old girl with biotin deficiency caused by amino acid formula. Two weeks after birth, she was diagnosed as having a milk protein allergy. After switching to amino acid formula from usual formula, her symptoms and laboratory findings became normal. About three weeks after the beginning of amino acid formula, she developed intractable skin erosions around the eyes, mouth, neck, and anogenital area. By measuring concentrations of some trace elements, she was diagnosed as having a biotin deficit, because of the organic aciduria and undetectable serum biotin concentration. Her serum biotinidase level was normal. Upon administration of oral biotin supplementation, all her symptoms and laboratory findings were dramatically improved. Since amino acid formula contains very few biotin, we should pay attention to biotin deficiency when infants receiving amino acid formula. 相似文献
47.
To characterize the medullary temperature-responsive neurones in rabbits, statistical analysis of interspike intervals was performed on 24 neurones recorded at various temperatures of the medulla. It was found that the medullary neurone fired at a relatively regular interval and 11 of 24 neurones displayed an invariable precision in thermoreception over a broad range of medullary temperatures; also, that the temporal distribution of interspike intervals of medullary neurones was markedly different from that of hypothalamic neurones. 相似文献
48.
Simultaneous occurrence of medullary and follicular carcinoma in the same thyroid lobe 总被引:2,自引:0,他引:2
T Tanaka N Yoshimi N Kanai H Mori K Nagai A Fujii S Sakata N Tokimitsu 《Human pathology》1989,20(1):83-86
A rare case of the simultaneous development of medullary and follicular carcinoma of the thyroid gland in a 51-year-old Japanese woman is examined. A preoperative diagnosis was made by needle aspiration cytology. Neoplastic cells of the medullary carcinoma were positive for calcitonin and carcinoembryonic antigen, whereas the tumor cells of the follicular carcinoma were negative for these substances. This case presents evidence that, in rare cases, two malignant epithelial neoplasms of different origins can occur in the same lobe of the thyroid. 相似文献
49.
Effect on blood glucose concentration of changes in availability of glucose to the brain 总被引:2,自引:0,他引:2
Sakata Kazuki; Hayano Shigeo; Sloviter Henry A. 《The American journal of physiology》1963,204(6):1127-1132
50.
Yamada A 《Shinrigaku kenkyu : The Japanese journal of psychology》2004,75(2):134-141
This study investigated the effects of repeated exposures to male and female targets on trait impressions and the role of stereotyped knowledge for the target's social category in impression formation process. The participants were repeatedly exposed to slides of male and female faces for subliminal durations. For each of 12 pairs containing both previously presented slide and newly presented slide, the participants made forced-choice liking judgments (Experiment 1), trait judgments (Experiment 2) and recognition judgments (Experiments 1 and 2). It was found that participants' attitude toward the targets became more positive, even though target recognition was not significantly greater than the chance level. Yet, when the dimension of judgment was stereotypically associated with the target's social category, exposure effects were obtained for the targets whose social category and its dimension were inferentially matched, but not obtained for the targets whose social category and its dimension were not inferentially matched. Some theoretical implications of the role of social category information in the mere exposure phenomenon are discussed. 相似文献