全文获取类型
收费全文 | 601篇 |
免费 | 35篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 30篇 |
妇产科学 | 1篇 |
基础医学 | 56篇 |
口腔科学 | 43篇 |
临床医学 | 48篇 |
内科学 | 149篇 |
皮肤病学 | 17篇 |
神经病学 | 10篇 |
特种医学 | 100篇 |
外科学 | 60篇 |
综合类 | 24篇 |
预防医学 | 36篇 |
眼科学 | 4篇 |
药学 | 45篇 |
中国医学 | 1篇 |
肿瘤学 | 16篇 |
出版年
2021年 | 15篇 |
2020年 | 5篇 |
2019年 | 2篇 |
2018年 | 9篇 |
2017年 | 4篇 |
2016年 | 11篇 |
2015年 | 12篇 |
2014年 | 12篇 |
2013年 | 33篇 |
2012年 | 23篇 |
2011年 | 16篇 |
2010年 | 28篇 |
2009年 | 27篇 |
2008年 | 21篇 |
2007年 | 12篇 |
2006年 | 21篇 |
2005年 | 18篇 |
2004年 | 14篇 |
2003年 | 13篇 |
2002年 | 11篇 |
2001年 | 11篇 |
2000年 | 9篇 |
1999年 | 20篇 |
1998年 | 35篇 |
1997年 | 26篇 |
1996年 | 21篇 |
1995年 | 13篇 |
1994年 | 23篇 |
1993年 | 23篇 |
1992年 | 7篇 |
1991年 | 11篇 |
1990年 | 5篇 |
1989年 | 13篇 |
1988年 | 16篇 |
1987年 | 9篇 |
1986年 | 14篇 |
1985年 | 7篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 12篇 |
1980年 | 12篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1970年 | 1篇 |
1957年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有643条查询结果,搜索用时 15 毫秒
571.
Neumayr G Ludwiczek O Hoertnagl H Pfister R Mitterbauer G Moschen A Novick D Rubinstein M Tilg H 《International journal of sports medicine》2005,26(10):836-840
Interleukin 18 (IL-18) is an important pro-inflammatory cytokine in the early phase of human immune response to microbial infections. The influence of strenuous exercise on the intrinsic balance of IL-18 and its endogenous antagonist IL-18 binding protein (IL-18 BP) is unknown, but could be of major relevance for the athlete's immune function empirically and epidemiologically proven to be altered after exhaustive exertion. To study the effect of strenuous marathon cycling on the interaction of IL-18 and IL-18 BP we investigated 37 male, healthy, and well-trained amateur cyclists participating in the Otztaler Radmarathon in Tyrol (distance: 230 km; cumulative altitude difference: 5500 m). IL-18 was measured by a commercially available ELISA-Kit and IL-18 BP by a novel IL-18 BP ELISA method. Free, unbound IL-18 was calculated according to a standard equation. The mean plasma level of IL-18 was 142.27 +/- 21.85 pg/ml pre-race, remained nearly unchanged (124.35 +/- 13.16 pg/ml; p = 1.0) immediately after competition (mean race time 9 h 38 min), but declined significantly 24 h afterward (62.92 +/- 6.80 pg/ml; p = 0.002). The plasma levels of IL-18 BP increased considerably immediately after and kept on rising for the following 24 h (pre-race: 1.51 +/- 0.20 ng/ml; immediately post-race: 3.84 +/- 0.26 ng/ml, p < 0.001; 24 h post-race: 4.33 +/- 0.42 ng/ml, p < 0.001). Therefore, the calculated free IL-18 was 122.06 +/- 16.79 pg/ml pre-race, declined to 82.86 +/- 8.59 (p = 0.05) immediately post-race and to 39.17 +/- 3.76 pg/ml 24 h post-race (p < 0.001). The respective percentages of this post-exercise reduction in free IL-18 plasma levels were 32 % and 68 %. The present study reveals an exercise-induced significant decline in free IL-18 accompanied by an immediate up-regulation of IL-18 BP and decreased IL-18 in marathon cyclists. This down-regulation of free IL-18 may (i) limit the magnitude and duration of a too excessive inflammatory response to the exercise-induced tissue damage and (ii) on the other hand contribute to the elevated susceptibility to infection in athletes undergoing exhaustive exercise. 相似文献
572.
Ways of accelerating recovery of the mucous membrane immune system in lethally irradiated mice following syngeneic bone marrow transplantation were studied over a 35-day period by quantification of jejunal intraepithelial lymphocytes (IELs) and lamina propria plasma cells. Recovery after a low bone marrow dose allowing 100% animal survival (LBM) was compared with a high (five times minimal) dose (HBM), or a minimal dose augmented with equal numbers of buffy coat cells (LBM + BC) or small gut mucosal lymphocytes (LBM + GL). The maximal decline and subsequent peak repopulation of IELs were: LBM, days 7 through 14, peaking suboptimally by day 28; HBM, day 14, peaking suboptimally but higher than LBM by day 35; LBM + BC, days 11 through 14, peaking at control levels by day 35; and LBM + GL, day 7, peaking at control levels by day 28. The IEL decline was most severe with LBM and HBM treatment and least with LBM + GL. All transplant groups experienced maximal plasma cell decline by day 7. LBM had the most severe depletion, and LBM + GL had the least. Recovery to control levels for the LBM, HBM, LBM + BC and LBM + GL groups occurred by days 28, 21, 21, and 14, respectively. In all instances, greater than 95% of the plasma cells were IgA positive. 相似文献
573.
574.
575.
Laser Doppler flowmetry (LDF) is a non-invasive method to assess pulpal blood-flow (PBF). Dental luxation injuries have been associated with significant PBF reduction. The purpose of this study was to describe diagnostic characteristics for different session-related threshold PBF values for detection of specific adverse outcomes. In 61 trauma patients, a single maxillary incisor treated by repositioning and splinting, and the respective contralateral homologous control tooth were investigated by LDF to assess local PBF values. Perfusion units (PU) were taken 12 weeks (session I) and 24 weeks (session II) after splint removal. The ability of session I-related PBF measurements at 2.8, 6.4 and 10.1 PU levels, and of session II-related ameasurements at 2.4, 6.3 and 10.2 PU levels to identify adverse outcomes occurring 36 weeks after splint removal was investigated. Adverse outcomes were classified as type I (periapical radiolucency), type II (grey discoloration), and type III (periapical radiolucency and grey discoloration of crown). Receiver operator characteristic curves were used to evaluate the sensitivity and specificity of PBF assessments. There was no significant difference in PBF values between session I and session II (P > 0.05) for teeth without an adverse outcome, and those with a type I, II or III outcome (P > 0.05). The PBF measurements did not change over time for the contralateral incisors (P > 0.05). A type I, II and III outcome occurred in 36, 21 and 12% of the incisors, respectively. The best likelihood ratio was found for the PBF 6.4 PU level at session I and incisors associated with a type I (20.8) and type II outcome (15.2). The PBV of 6.4 PU demonstrated a sensitivity of 96% and a specificity of 59% for type I outcomes, and a sensitivity of 100% and a specificity of 50% for type II outcomes. The data suggest the LDF test to be a valuable diagnostic adjunct for luxated teeth showing signs of adverse outcomes. 相似文献
576.
Emshoff R Moschen I Strobl H 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2004,98(6):750-755
OBJECTIVE: Splinting of traumatically displaced or avulsed permanent teeth has been described as an effective modality in the treatment of patients with dental injuries. The purpose of this study was to investigate whether laser Doppler flowmetry (LDF) measurements of pulpal blood flow (PBF) and/or dental injury type may predict treatment outcome of splinting of permanent maxillary incisors. STUDY DESIGN: The study comprised 64 patients undergoing dental trauma splinting, who were characterized by the presence of a single permanent maxillary incisor affected by a subluxation, luxation, or avulsion type injury. Perfusion units (PU) were taken in 2 sessions, on the day of splint removal (6 weeks after trauma; session I) and 12 weeks after splint removal (session II). At each session, when an injured permanent maxillary central incisor was recorded, the respective contralateral homologous tooth was used as a control. An adverse outcome occurring 36 weeks after splint removal was defined as the presence of "periapical radiolucency and/or grey discoloration." A multiple logistic regression analysis was used to compute the odds ratio for session-related PBF characteristics and dental injury type for adverse outcome (n=22) versus nonadverse outcome (n=42). RESULTS: There was a significant increase in PBF values from session I to session II (P=.047) for teeth without an adverse outcome, whereas teeth affected by an adverse outcome showed a significant decrease in PBF values (P=.001). PBF measurements did not change over time for the control group of contralateral incisors (P=.185). For the outcome criterion of "presence of periapical radiolucency and/or grey discoloration," there was a significant association between the treatment outcome groups and the variables of dental injury type (P=.049), session-related PBF difference (P=.000), and session II-related PBF level (P=.000). Significant increase in risk of an adverse outcome occurred with a session-related PBF difference (PBF(Session I) - PBF(Session II)) of >/=0 PU (8.6 odds ratio) (P=.014), and a session II-related PBF level of =2.8 PU (20.2 odds ratio) (P=.030). CONCLUSION: The data suggest the LDF test to be a valuable diagnostic adjunct for luxated teeth showing signs of adverse outcomes. Predictive modeling may provide clinicians with the opportunity to identify "at-risk" teeth early and initiate specific treatments. 相似文献
577.
Background.
Gastric carcinoma is a tumor that shows marked differences in geographic distributions. The incidence of the gastric carcinoma
has been falling dramatically in Western countries. In sharp contrast, the incidence in Japan is still quite high.
Methods.
A comparative clinicopathological study was performed, examining gastric carcinomas in 978 Japanese patients (Tokyo) and 157
United States patients (San Diego), that had been surgically resected over the 11-year period 1980–1991.
Results.
The median age of US the patients (64.1 years) was higher than that of the Japanese patients (59.0 years). There was no difference
in the sex ratios. Forty-five of the Japanese patients had early gastric cancer, while this occurred in 10% of the US patients.
In terms of tumor location, 47% were in the upper portion of the stomach in the US patients, while, in contrast, this proportion
in Japanese patients was 23%. In association with the marked difference in tumor location, 36.5% of the US patients underwent
operations with the thoraco-abdominal approach, while this approach was used in 7.5% of the Japanese patients. The distribution
of histological types was similar in the two countries' samples. There was also no significant difference in the distribution
of the histological types in the same age groups in the two countries' samples. The rate of the well differentiated type increased
with age while the rate of poorly differentiated type decreased. In US patients, 35.8% had marked neural invasion, while this
occurred in 8.5% of Japanese patients.
Conclusion.
This study revealed marked differences in the features of gastric cancer between the US and Japan in terms of tumor location
and surgical procedures.
Received for publication on February 18, 1998; accepted on May 25, 1998 相似文献
578.
Elevated mammaglobin (<Emphasis Type="Italic">h-MAM</Emphasis>) expression in breast cancer is associated with clinical and biological features defining a less aggressive tumour phenotype 总被引:6,自引:0,他引:6
下载免费PDF全文
![点击此处可从《Breast cancer research : BCR》网站下载免费的PDF全文](/ch/ext_images/free.gif)
579.
The influence of recombinant erythropoietin (Ep) and interleukin-3 (IL- 3) on the proliferation and differentiation of murine hematopoietic stem and progenitor cells was investigated in serum-deprived cultures. The differentiation of progenitor cells, purified by collecting blast cell colonies from spleen cell cultures of 5-fluorouracil-treated mice, was evaluated by scoring the number and type of colonies appearing after eight days in semisolid culture. IL-3 induced the formation of both erythroid and granulocyte-macrophage colonies in a concentration- dependent fashion, the plateau being reached at 300 U/mL. However, concentrations of IL-3 alone that had little or no effect (less than or equal to 10 U/mL) induced maximal numbers of erythroid bursts in the presence of Ep (1.5 IU/mL). In the presence of Ep alone, no colonies were seen. Proliferation of quiescent hematopoietic stem cells, purified by cell sorting and evaluated by spleen colony assay (CFU-S), was investigated by measuring the total cell number and CFU-S content and the DNA histogram at 20 and 48 hours of liquid culture. Almost no cells or CFU-S survived 20 hours of incubation without the addition of IL-3. The presence of either IL-3 (400 U/mL) or the combination of EP and IL-3 (10 U/mL), supported the maintenance of nearly 40% of sorted CFU-S for 48 hours. Approximately 10% of these cells were in the S phase of the cell cycle at 20 hours and an increase in the total cell number per culture, but not in the CFU-S content, was detected at 48 hours. These data indicate that IL-3 exerts a differentiative and proliferative effect on early stem and progenitor cells, which is concentration dependent. At IL-3 concentrations, which had little or no activity alone, Ep acted synergistically to induce both proliferation of stem cells and differentiation of erythroid progenitors. 相似文献
580.
MR imaging of laser-tissue interactions 总被引:6,自引:0,他引:6
A new application of magnetic resonance (MR) imaging to map the spatial and temporal distribution of the effects of Nd:YAG lasers on tissues was studied. The temperature dependence of MR relaxation mechanisms and the high sensitivity of MR to changes in the mobility and distribution of tissue water make it particularly suitable for the demonstration and control of thermal energy deposition in tissues. In heterogeneous tissues, MR imaging does not follow changing temperatures directly because even in the case of reversible thermal interactions, there is a hysteresis in the dynamic relationship between MR signal intensity and temperature. Appropriate matching of the laser and MR pulse sequences can, however, optimize the detection of relatively small laser energy deposition, and reversible and irreversible tissue changes can be distinguished. There is a potential for the integration of MR imaging and lasers for three-dimensional control and monitoring of laser-tissue interactions. 相似文献