全文获取类型
收费全文 | 15280篇 |
免费 | 732篇 |
国内免费 | 143篇 |
专业分类
耳鼻咽喉 | 168篇 |
儿科学 | 326篇 |
妇产科学 | 151篇 |
基础医学 | 1576篇 |
口腔科学 | 259篇 |
临床医学 | 986篇 |
内科学 | 4086篇 |
皮肤病学 | 218篇 |
神经病学 | 902篇 |
特种医学 | 517篇 |
外科学 | 3147篇 |
综合类 | 74篇 |
一般理论 | 1篇 |
预防医学 | 317篇 |
眼科学 | 226篇 |
药学 | 948篇 |
中国医学 | 21篇 |
肿瘤学 | 2232篇 |
出版年
2023年 | 105篇 |
2022年 | 209篇 |
2021年 | 390篇 |
2020年 | 229篇 |
2019年 | 293篇 |
2018年 | 364篇 |
2017年 | 320篇 |
2016年 | 390篇 |
2015年 | 419篇 |
2014年 | 527篇 |
2013年 | 607篇 |
2012年 | 1002篇 |
2011年 | 1100篇 |
2010年 | 644篇 |
2009年 | 524篇 |
2008年 | 894篇 |
2007年 | 944篇 |
2006年 | 971篇 |
2005年 | 970篇 |
2004年 | 952篇 |
2003年 | 923篇 |
2002年 | 911篇 |
2001年 | 196篇 |
2000年 | 181篇 |
1999年 | 233篇 |
1998年 | 187篇 |
1997年 | 165篇 |
1996年 | 139篇 |
1995年 | 121篇 |
1994年 | 133篇 |
1993年 | 114篇 |
1992年 | 98篇 |
1991年 | 115篇 |
1990年 | 77篇 |
1989年 | 88篇 |
1988年 | 96篇 |
1987年 | 67篇 |
1986年 | 55篇 |
1985年 | 38篇 |
1984年 | 45篇 |
1983年 | 43篇 |
1982年 | 25篇 |
1981年 | 15篇 |
1980年 | 17篇 |
1979年 | 34篇 |
1978年 | 18篇 |
1973年 | 15篇 |
1971年 | 18篇 |
1969年 | 16篇 |
1966年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
41.
Komei Ito Masaki Futamura Yuri Takaoka Masashi Morishita Kumiko Nakanishi Tatsuo Sakamoto 《Arerugī》2008,57(8):1043-1052
Background: A method for open food challenge test to determine food allergy has not been established in an evidence-based manner. Methods: We conducted an analysis of 438 open food challenges of raw milk (n=133, mean age 2.7+/-1.9 years), boiled egg white (n=216, 2.8+/-2.1 years) or udon noodles (n=89, 2.7+/-1.7 years) for the patients aged 1 year or more. Doses were increased (trace amounts, 1 g, 2 g, 5 g, 10 g, 20-30 g) every 20 minutes. Results: In total, 151 (38.5%) of food challenges were positive. The positive rates of milk, egg and wheat challenges were 35.8%, 42.4% and 33.3%, respectively. Of these, 76.2%, 32.5%, 27.8% and 0.7% had, respectively, skin, respiratory, gastrointestinal and cardiovascular symptoms. Although the prevalence of positive challenge increased with level of specific IgE, it did not correlate with the threshold amount of positive food challenge or the severity of symptoms. Among the challnege positive patients, 10.6% required injection of antihistamines, corticosteroids or adrenalines for the treatment of the symptoms. Conclusions: This challenge protocol seemed to be appropriate and safe. 相似文献
42.
Sasaki J Sugawara K Tanno Y 《Shinrigaku kenkyu : The Japanese journal of psychology》2005,76(5):445-452
The aim of the present study is to explain why there is "the diverse U letter relationship" between embarrassment and psychological distance empirically, in view of Schlenker and Leary (1982)'s self-presentation model of social anxiety. In Study 1, those relationships were observed in three different situations. In Study 2, the main effect of motivation for avoiding rejection and the damage of self-image, and their interaction with embarrassment was examined by hierarchical regression analysis. In the first step, the psychological distance, in the second step, the main effect of both, and in the third step, the interaction was entered. As a result, in the second step, both main effects were significant, but in the third step, only interaction was significant, and both main effects were not significant. This showed that the interaction could predict embarrassment, although the psychological distance was controlled. Finally, this result was discussed in view of social norm. 相似文献
43.
Takashi Kojima Toshinobu Yamamoto Mengdong Lan Masaki Murata Ken-ichi Takano Mitsuru Go Shingo Ichimiya Hideki Chiba Norimasa Sawada 《Medical Electron Microscopy》2004,37(2):101-113
The signal transduction pathways and activation of the MAP kinase or PI3 kinase signaling cascade regulate a variety of cellular processes, including proliferation and differentiation in hepatocytes. To elucidate the mechanisms of signal transmission required for the regulation of gap and tight junctions during DNA synthesis in rat hepatocytes, we determined changes of expression and function of gap and tight junctions of cells grown in primary culture, using inhibitors of signaling pathways for MAP kinase (PD98059) and PI3 kinase (LY294002). During the stimulation of DNA synthesis induced by epidermal growth factor (EGF), immunoreactivity and mRNAs of gap junction protein Cx32 and of tight junction protein claudin-1 markedly decreased with reduction of gap junctional intercellular communication (GJIC) and the fence function of tight junctions. In Western blots, whole-cell lysate of claudin-1 protein decreased and phosphorylated Cx32 protein in the insoluble fraction of Triton X-100 increased during the stimulation of DNA synthesis. During reinhibition of DNA synthesis, the changes of Cx32 and claudin-1 returned to control levels, as did both functions. In treatment with the inhibitors before DNA synthesis, PD98059 inhibited the changes of expression and function of Cx32, but not claudin-1, without inhibition of cell growth, whereas LY294002 completely inhibited cell growth. These findings indicate that the PI3 kinase pathway rather than the MAP kinase pathway plays an important role for EGF-induced proliferation of rat hepatocytes, and that changes of Cx32 in hepatocytes during the stimulation of DNA synthesis may be in part controlled through MAP kinase. Furthermore, Cx32, but not claudin-1, protein may be a target of activated MAP kinase in hepatocytes. 相似文献
44.
Ghrelin Induces Fasted Motor Activity of the Gastrointestinal Tract in Conscious Fed Rats 总被引:15,自引:1,他引:15
Kazunori Fujino Akio Inui† Akihiro Asakawa† Naoki Kihara Masaki Fujimura Mineko Fujimiya‡ 《The Journal of physiology》2003,550(1):227-240
Ghrelin is a newly discovered orexigenic peptide originating from the stomach. However, its action in regulating the fed and fasted motor activity of the digestive tract is not fully understood. In the present study, we examined the effects of intracerebroventricular ( i.c.v. ) and intravenous ( i.v. ) injection of ghrelin on the physiological fed and fasted motor activities in the stomach and duodenum of freely moving conscious rats. i.c.v. and i.v. injection of ghrelin induced fasted motor activity in the duodenum in normal fed rats, while i.v. injection of ghrelin induced fasted motor activity in both the stomach and duodenum in vagotomized rats. The effects of i.c.v. and i.v. injected ghrelin were blocked by growth hormone secretagogue receptor (GHS-R) antagonist given by the same route and also blocked by immunoneutralization of neuropeptide Y (NPY) in the brain. The effects of i.v. injected ghrelin were not altered by i.c.v. injection of GHS-R antagonist in vagotomized rats. Injection of GHS-R antagonist blocked the fasted motor activity in both the stomach and duodenum in vagotomized rats but did not affect the fasted motor activity in normal rats. Low intragastric pH inhibited the effect of ghrelin. The present results indicate that ghrelin is involved in regulation of fasted motor activity in the stomach and duodenum. Peripheral ghrelin may induce the fasted motor activity by activating the NPY neurons in the brain, probably through ghrelin receptors on vagal afferent neurons. Once the brain mechanism is eliminated by truncal vagotomy, ghrelin might be primarily involved in the regulation of fasted motor activity through ghrelin receptors on the stomach and duodenum. The action of ghrelin to induce fasted motor activity is strongly affected by intragastric pH; low pH inhibits the action. 相似文献
45.
Atsuta I Yamaza T Yoshinari M Goto T Kido MA Kagiya T Mino S Shimono M Tanaka T 《Biomaterials》2005,26(32):6280-6287
Laminin-5 (Ln-5) is an important molecule associated with epithelial cell adhesion and migration. In the gingiva around the tooth, Ln-5 localizes within basement membranes between the junctional epithelium (JE) and the tooth or connective tissue. Recently, we reported that in the oral mucosa around a dental implant, Ln-5 is expressed within the basement membranes at the implant-peri-implant epithelium (PIE) interface, and at the PIE-connective tissue interface. However, the ultrastructural localization of Ln-5 within or along the PIE has not yet been reported. Therefore, peri-implant oral mucosa was treated with anti-Ln-5 (gamma2 chain) antibody and examined using immuno-electron microscopy. Ln-5 was localized in the cells of the innermost-third layer and basal layer of the PIE. A 100-nm-wide Ln-5-positive internal basal lamina (basement membrane) and hemidesmosomes as adhesion structures were formed at the apical portion of the implant-PIE interface. However, at the upper-middle portion of the interface, these adhesion structures were not observed. Furthermore, at the PIE-connective tissue interface, the Ln-5-positive external basal lamina (basement membrane) and hemidesmosomes were partially deficient. Judging from these findings, we concluded that Ln-5 contributes to the attachment of the PIE to the titanium surface, and that PIE attached to titanium at the apical portion of the dental implant-PIE interface. 相似文献
46.
Tanaka K Tamura J Kawanabe K Nawa M Uchida M Kokubo T Nakamura T 《Journal of biomedical materials research. Part A》2003,67(1):200-207
Recently zirconia/alumina composites have been examined by many researchers as the new generation of bearing materials in total joint replacements. In this study, the phase stability of a Ce-TZP/Al(2)O(3) nanocomposite and conventional Y-TZP after aging, and its influence on wear resistance, were investigated. Very slight phase transformation was observed in both types of ceramics 18 months after the implantation of Ce-TZP/Al(2)O(3) or Y-TZP samples into rabbit tibiae. However, Y-TZP showed marked phase transformation (approximately 80%) after aging in an autoclave (121 degrees C) for 190 h or in physiological saline at 62 degrees C for 18 months, whereas the new composite remained almost resistant to degradation. According to the results of self-pairing pin-on-disk wear tests using ceramic specimens with or without autoclave aging, the wear factor was almost the same between Ce-TZP/Al(2)O(3) samples with and without aging (6.74 +/- 0.36 x 10(-8) and 6.04 +/- 0.95 x 10(-8) mm(3)/Nm, respectively). In contrast, although non-aged Y-TZP had the lowest wear factor (4.88 +/- 0.51 x 10(-8) mm(3)/Nm) of all specimens tested, aged Y-TZP showed 10-fold greater wear than nonaged Y-TZP. The present study suggests that Ce-TZP/Al(2)O(3) nanocomposite has much greater phase stability than Y-TZP, and that its wear properties are not influenced by aging. 相似文献
47.
48.
49.
This study examined the effects of voluntary abdominal breathing (VAB) on the electroencephalogram (EEG) in 22 healthy subjects. VAB was characterized by prolonged rhythmic contraction of abdominal muscles for 20 min in an eyes-closed condition. The breathing rate was instructed to be very slow, i.e., 3-4 breaths/min (inspiratory time for 6-8s and expiratory time for 9-12s). A low-frequency alpha band appeared immediately after eye closing, but it later disappeared and was replaced by a new development of a high-frequency alpha band 4-5 min after the onset of VAB. The subjects had a feeling of vigor-activity with a tendency of reduced anxiety during and/or after VAB, as assessed by POMS and STAI questionnaire scores. On the other hand, during resting in the eye-closed condition, the disappearance of the low-frequency alpha band was replaced by the occurrence of a theta/delta band. The subjects became drowsy in this condition. We therefore conclude that the increase in high-frequency alpha activity is linked to the state of vigor-activity with a tendency of reduced anxiety. Since the urinary serotonergic level significantly increased after the VAB, we suggest that the serotonergic neurons within the brain may produce the changes in the EEG patterns. 相似文献
50.