全文获取类型
收费全文 | 251篇 |
免费 | 12篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 12篇 |
妇产科学 | 7篇 |
基础医学 | 40篇 |
口腔科学 | 2篇 |
临床医学 | 35篇 |
内科学 | 53篇 |
皮肤病学 | 3篇 |
神经病学 | 9篇 |
特种医学 | 19篇 |
外科学 | 10篇 |
综合类 | 20篇 |
预防医学 | 23篇 |
药学 | 20篇 |
肿瘤学 | 12篇 |
出版年
2022年 | 3篇 |
2021年 | 8篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 10篇 |
2012年 | 4篇 |
2011年 | 5篇 |
2010年 | 6篇 |
2009年 | 12篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 8篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 19篇 |
1997年 | 15篇 |
1996年 | 11篇 |
1995年 | 7篇 |
1994年 | 10篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 10篇 |
1987年 | 9篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1982年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1967年 | 1篇 |
1954年 | 1篇 |
1949年 | 1篇 |
排序方式: 共有266条查询结果,搜索用时 234 毫秒
1.
G M McEntee B H Simbi S A Bayol R G Macharia N C Stickland 《Developmental dynamics》2006,235(7):1777-1784
Insulin-like growth factor (IGF) -1 and -2 and binding protein (IGFBP-2, -4, and -5) expression can be affected by several environmental factors, but the impact of movement on the IGF axis during late embryogenesis has yet to be fully characterized. Movement was promoted in chick embryos during mid-embryogenesis using 4-aminopyridine (4-AP). The results indicate an increase in IGF-1 (P < 0.01) and a decrease in IGFBP-2 (P < 0.05) mRNA expression in slow muscle of the stimulated group compared with the control group. In fast muscle, there was a decrease in IGF-2 (P < 0.01) on embryonic day (ED) 16 and an increase in IGFBP-2 (P < 0.01) and IGFBP-4 (P < 0.05) and in IGFBP-5 (P < 0.05) expression on ED18 in the stimulated group compared with the control group. These results indicate that neuromuscular stimulation with 4-AP influences IGF axis gene expression in a muscle fiber type-dependent manner. Consequences of the changes in the IGF system for each muscle are discussed. 相似文献
2.
Arbour NC; Zlotogora J; Knowlton RG; Merin S; Rosenmann A; Kanis AB; Rokhlina T; Stone EM; Sheffield VC 《Human molecular genetics》1997,6(5):689-694
Achromatopsia is an autosomal recessive disease of the retina,
characterized clinically by an inability to distinguish colors, impaired
visual acuity, nystagmus and photophobia. A genome-wide search for linkage
was performed using an inbred Jewish kindred from Iran. To facilitate the
genome-wide search, we utilized a DNA pooling strategy which takes
advantage of the likelihood that the disease in this inbred kindred is
inherited by all affected individuals from a common founder. Equal molar
amounts of DNA from all affected individuals were pooled and used as the
PCR template for short tandem repeat polymorphic markers (STRPs). Pooled
DNA from unaffected members of the kindred was used as a control. A
reduction in the number of alleles in the affected versus control pool was
observed at several loci. Upon genotyping of individual family members,
significant linkage was established between the disease phenotype and
markers localized on chromosome 2. The highest LOD score observed was 5.4
(theta = 0). When four additional small unrelated families were genotyped,
the combined peak LOD score was 8.2. Analysis of recombinant chromosomes
revealed that the disease gene lies within a 30 cM interval which spans the
centromere. Additional fine-mapping studies identified a region of
homozygosity in all affected individuals, narrowing the region to 14 cM. A
candidate gene for achromatopsia was excluded from this disease interval by
radiation hybrid mapping. Linkage of achromatopsia to chromosome 2 is an
essential first step in the identification of the disease-causing gene.
相似文献
3.
4.
The effects of cycle racing on pulmonary diffusion capacity and left ventricular systolic function 总被引:1,自引:0,他引:1
Stickland MK Petersen SR Haykowsky MJ Taylor DA Jones RL 《Respiratory physiology & neurobiology》2003,138(2-3):291-299
The purpose of this study was to examine the effects of a 20 km cycle race (TT) on left ventricular (LV) systolic and pulmonary function in 12 endurance cyclists. Spirometry, single-breath diffusion capacity (DLCO) with partitioning of membrane (DM) and capillary blood volume (Vc) components and 2-D echocardiograms were performed before and after the TT. During the TT mean oxygen consumption was 3.79 +/- 0.5 L x min(-1) (83 +/- 5.5% of VO2max) and mean blood lactate was 8.4 +/- 2.4 mM. Following the TT, spirometry values were unchanged, however, DLCO and DM were significantly (P<0.05) reduced. LV systolic function was increased (P<0.05) immediately after exercise, while end-diastolic area was decreased (P<0.05) at all points during recovery. The reduction in DM was correlated with LV systolic function following the TT. This relationship suggests a cardiovascular contribution to pulmonary diffusion impairment following exercise. 相似文献
5.
6.
7.
Frances M. Sobierajski Graeme M. Purdy Charlotte W. Usselman Rachel J. Skow Marina A. James Radha S. Chari Rshmi Khurana Michael K. Stickland Sandra T. Davidge Maureen Devolin Craig D. Steinback Margie H. Davenport 《The Canadian journal of cardiology》2018,34(4):485-491
Background
Cardiovagal baroreflex gain (cBRG) reflects an individual's ability to buffer swings in blood pressure. It is not well understood how this mechanism is influenced by physical activity in pregnancy. Because pregnant women tend to engage in low levels of moderate-to-vigorous physical activity (MVPA) and high levels of sedentary behaviour, we sought to determine the influence of MVPA and sedentary behaviour on cBRG and mean arterial pressure (MAP) in pregnancy.Methods
Fifty-eight third trimester (31.9 ± 3.0 weeks) normotensive pregnant women (31.2 ± 2.8 years) were tested. Heart rate (electrocardiogram) and blood pressure (systolic blood pressure and MAP; finger photoplethysmography) were collected on a beat-by-beat basis, and averaged over 3 minutes of rest. Spontaneous cBRG was calculated as the slope of the relationship between fluctuations in systolic blood pressure and heart rate. Objective measures of MVPA and sedentary behaviour were collected over a 7-day period using an ActiGraph accelerometer (model wGTX3-BT; ActiGraph LLC, Pensacola, FL).Results
Participants spent 67.5 ± 7.9% of waking hours engaged in sedentary behaviour, and performed 68.6 ± 91.9 minutes of MVPA per week. Sedentary behaviour was not related to cBRG (r = ?0.035; P = 0.793) or MAP (r = ?0.033; P = 0.803). However, MVPA was positively associated with cBRG (r = 0.315; P = 0.016), but not MAP (r = ?0.115; P = 0.389). The association between MVPA and cBRG remained significant after controlling for age, pre-pregnancy body mass index, gestational age, and wear time (r = 0.338; P = 0.013), indicating that women who engaged in greater amounts of MVPA showed increased cBRG.Conclusions
Our data suggest that increased MVPA, but not necessarily reduced sedentary behaviour, might be beneficial for reflex control of blood pressure during pregnancy. 相似文献8.
In vivo expression of the B7 costimulatory molecule by subsets of antigen-presenting cells and the malignant cells of Hodgkin's disease 总被引:10,自引:0,他引:10
Munro JM; Freedman AS; Aster JC; Gribben JG; Lee NC; Rhynhart KK; Banchereau J; Nadler LM 《Blood》1994,83(3):793-798
The B-lymphocyte/accessory-cell activation antigen B7 (BB1) has been shown in vitro to stimulate T-lymphocyte proliferation and cytokine production via CD28 present on the latter cells. In this study, benign lymphoid tissues, lymphomas, and extralymphoid inflammatory sites were examined immunohistochemically using anti-B7 and other relevant monoclonal antibodies. B7 was expressed by benign transformed germinal center B cells, as it was by B cells of follicular lymphomas. B7 was also expressed by a subpopulation (a mean of 31% to 65%) of macrophages and dendritic cells in a variety of lymphoid tissues. It was present in abundance on all macrophages constituting sarcoid granulomas in lymph nodes. In extralymphoid inflammation, 17% to 35% of macrophages expressed B7 only weakly. Cases of Hodgkin's disease showed expression of B7 by the majority of Reed-Sternberg cells or malignant mononuclear variants, a phenomenon that potentially contributes to the lymphocytic accumulation that is a feature of this condition. CD28+ T cells were seen in all areas where T cells were present. B7+ and CD28+ cells colocalized in, for example, lymphoid follicles, lymph node paracortex, sarcoid granulomas, and Hodgkin's disease tissue, indicating a potential for cellular interaction via these molecules at these sites. 相似文献
9.
Eric Y. Wong Cally A. Jennings Wendy M. Rodgers Anne-Marie Selzler Lindsay G. Simmonds Rashida Hamir Michael K. Stickland 《Patient education and counseling》2014
Objective
This study examined if ongoing support delivered by telephone following pulmonary rehabilitation (PR) assisted chronic obstructive pulmonary disease (COPD) patients to maintain health outcomes.Methods
Phase one (n = 79) compared post-rehabilitation telephone-based support delivered by peers compared to usual care (UC). The second phase (n = 168) compared post-rehabilitation support from peer educators, respiratory therapists (RT), or UC. Primary outcome variables were St. George's Respiratory Questionnaire (SGRQ) total score and the six minute walk test (6MWT). Measures were obtained at baseline, immediately following PR, and six-months post PR.Results
Six-month follow-up data for phase one was collected for 66 COPD patients (n = 35 peer support, n = 31 UC) and 142 for phase two (n = 42 peer support, n = 52 RT support, n = 48 UC). Per-protocol and intention to treat (ITT) analysis in both phases found no significant group by time differences for SGRQ or 6MWT.Conclusion
Providing peer or RT support via telephone following PR was not more effective than UC for maintaining health outcomes.Practice implications
There are concerns with using peers to provide ongoing support to COPD patients. Additionally, COPD patients require a higher level of care than telephone support can provide. 相似文献10.
Carotid chemoreceptor modulation of sympathetic vasoconstrictor outflow during exercise in healthy humans 总被引:1,自引:0,他引:1
Recently, we have shown that specific, transient carotid chemoreceptor (CC) inhibition in exercising dogs causes vasodilatation in limb muscle. The purpose of the present investigation was to determine if CC suppression reduces muscle sympathetic nerve activity (MSNA) in exercising humans. Healthy subjects ( N = 7) breathed hyperoxic gas ( F IO2 ∼1.0) for 60 s at rest and during rhythmic handgrip exercise (50% maximal voluntary contraction, 20 r.p.m.). Microneurography was used to record MSNA in the peroneal nerve. End-tidal P CO2 was maintained at resting eupnoeic levels throughout and breathing rate was voluntarily fixed. Exercise increased heart rate (67 versus 77 beats min−1 ), mean blood pressure (81 versus 97 mmHg), MSNA burst frequency (28 versus 37 bursts min−1 ) and MSNA total minute activity (5.7 versus 9.3 units), but did not change blood lactate (0.7 versus 0.7 m m ). Transient hyperoxia had no significant effect on MSNA at rest. In contrast, during exercise both MSNA burst frequency and total minute activity were significantly reduced with hyperoxia. MSNA burst frequency was reduced within 9–23 s of end-tidal P O2 exceeding 250 mmHg. The average nadir in MSNA burst frequency and total minute activity was −28 ± 2% and −39 ± 7%, respectively, below steady state normoxic values. Blood pressure was unchanged with hyperoxia at rest or during exercise. CC stimulation with transient hypoxia increased MSNA with a similar time delay to that obtained with CC inhibition via hyperoxia. Consistent with previous animal work, these data indicate that the CC contributes to exercise-induced increases in sympathetic vasoconstrictor outflow. 相似文献