全文获取类型
收费全文 | 190篇 |
免费 | 19篇 |
出版年
2016年 | 5篇 |
2015年 | 6篇 |
2014年 | 4篇 |
2013年 | 10篇 |
2012年 | 4篇 |
2007年 | 4篇 |
2006年 | 10篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 6篇 |
1998年 | 3篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1992年 | 2篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 8篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1976年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1969年 | 3篇 |
1968年 | 4篇 |
1967年 | 2篇 |
1964年 | 3篇 |
1963年 | 4篇 |
1962年 | 4篇 |
1961年 | 3篇 |
1960年 | 2篇 |
1959年 | 3篇 |
1958年 | 5篇 |
1957年 | 7篇 |
1956年 | 4篇 |
1955年 | 2篇 |
1954年 | 2篇 |
1953年 | 3篇 |
1951年 | 2篇 |
1950年 | 4篇 |
1949年 | 2篇 |
1944年 | 2篇 |
1936年 | 2篇 |
排序方式: 共有209条查询结果,搜索用时 906 毫秒
121.
Kompatscher P Manestar M Schuster A Lang A Beer GM 《Plastic and reconstructive surgery》2005,115(1):77-83
The purpose of this study was to investigate the presence and the precise course of the pectoral branch of the thoracoacromial vessels on the underside of the pectoralis major muscle by anatomical dissection and by color Doppler ultrasound. A further goal was to determine whether these vessels were suitable as recipient vessels in microsurgery and supermicrosurgery for breast reconstruction. In 18 cadavers, the pectoral branch of the thoracoacromial vessels was followed caudally until the diameter of the artery diminished to 1 mm. The same examination was carried out in 40 young female volunteers by tracing the vessel course with color Doppler ultrasound. The 1-mm cutoff point of the artery was measured with reference to the manubrium, the midsternal line, the clavicle, and the upper border of the closest rib. In addition, in the cadavers, the 2-mm cutoff point was determined. At both cutoff points, the diameter of the accompanying vein was measured. The pectoral branch of the thoracoacromial vessels with the artery and concomitant veins could be detected on all 100 undersides of the pectoralis major muscle, anatomically and sonographically. In their course from the acromial region downward, the arteries reached a diameter of 1 mm at an average of 9.9 cm from the manubrium, horizontally 9.4 cm from the midsternal line, and vertically 4.0 cm from the lower border of the clavicle. The 1-mm reference point was situated on the upper border of the third rib in 85 percent of cases. The average distance between the 1-mm and the 2-mm cutoff points was 3.5 cm. At the 1-mm cutoff point, the diameter of the vein was 0.9 mm, and at the 2-mm cutoff point, it was 1.7 mm. Because of their central position at the anterior hemithorax, these vessels are easily accessible from mastectomy incisions, even in skin-sparing mastectomies; the donor-site morbidity is negligible; and as the diameters of the vessels gradually decrease along their caudal course, the recipient site can be chosen precisely according to the length and the diameter of the donor vessels and major mismatch can be avoided. Thus, the pectoral branches of the thoracoacromial vessels are well suited as recipient vessels for (super)microsurgery and are a very promising addendum to the thoracodorsal and internal mammary vessels. 相似文献
122.
123.
Elisabeth Tschermak-Woess Gertrude Hasitschka-Jenschke 《Plant Systematics and Evolution》1963,110(4):468-480
Zusammenfassung Pflanzen vonRhinanthus serotinus aus einer Population in Niederösterreich besitzen so wie an anderen mitteleuropäischen und an nordeuropäischen Fundorten im haploiden Satz außer 7 größeren 4 winzige Chromosomen. Auch beiRh. alectorolophus von einem Fundort bei Lunz am See (Niederösterreich) treten diese Chromosomen auf.In Übereinstimmung mit v.Witsch (1950) kann man sie hypothetisch als B-Chromosomen einer besonderen Kategorie auffassen. Dafür spricht neben ihrer geringen Größe, daß sie beiRh. alectorolophus total und beiRh. serotinus zum Großteil oder wahrscheinlich gleichfalls total heterochromatisch sind. Außerdem verhalten sie sich in den endopolyploiden Riesenkernen des chalazalen Endospermhaustoriums beiRh. serotinus anders als die A-Chromosomen. Die endomitotischen Abkömmlinge (=Endochromosomen) der A-Chromosomen sind nämlich so wie beiRh. alectorolophus stets zu Riesenchromosomen vereinigt, während die vermehrten B-Chromosomen vorwiegend winzige Einzelchromozentren, daneben zwei- und vierwertige und vereinzelt offenbar mehrwertige Endochromozentren bilden.BeiRh. alectorolophus schließen die B-Endochromosomen anscheinend durchgehend zu unregelmäßig geformten Endochromozentren oder stabförmigen Gebilden — B-Riesenchromosomen — zusammen. 相似文献
124.
Spectral sensitivity was measured in air in the light adapted state in two harbor seals and a South American sea lion using a behavioral training technique. Increment thresholds were determined in a spectral range from 390 nm to 670 nm in a simultaneous two‐choice discrimination task. The spectral sensitivity curves show two maxima in sensitivity, one main peak with a maximum around 500 nm in the harbor seal and around 550 nm in the South American sea lion, and a second, smaller peak with a maximum in the range of 410 nm in both species. The broad shape and the position of the maximum of the spectral sensitivity curve of the harbor seals suggests that even under photopic conditions both rods and cones are contributing to the measurements since harbor seals possess only one cone type. The maximum sensitivity in the green part of the spectrum may indicate an adaptation to a specific underwater environment. 相似文献
125.
Gertrude M. Tyce Duane K. Rorie David E. Byer David R. Danielson 《Journal of neurochemistry》1985,44(1):322-324
Significant amounts of acid-hydrolyzable conjugates of 3,4-dihydroxyphenylethylamine, norepinephrine, and 5-hydroxytryptamine were detected in lumbar CSF from 22 awake unpremedicated healthy individuals. In the CSF samples, the amounts of conjugated amines almost always exceeded the amounts of free amines, but were less than the amounts of the acid metabolites 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindoleacetic acid. 相似文献
126.
M. Katherine Charles Mary Lou Lindegren C. William Wester Meridith Blevins Timothy R. Sterling Nguyen Thi Dung Jean Claude Dusingize Divine Avit-Edi Nicolas Durier Barbara Castelnuovo Gertrude Nakigozi Claudia P. Cortes Marie Ballif Lukas Fenner International epidemiology Databases to Evaluate AIDS Collaboration 《PloS one》2016,11(4)
SettingWorld Health Organization advocates for integration of HIV-tuberculosis (TB) services and recommends intensive case finding (ICF), isoniazid preventive therapy (IPT), and infection control (“Three I’s”) for TB prevention and control among persons living with HIV.ObjectiveTo assess the implementation of the “Three I’s” of TB-control at HIV treatment sites in lower income countries.DesignSurvey conducted between March-July, 2012 at 47 sites in 26 countries: 6 (13%) Asia Pacific, 7 (15%), Caribbean, Central and South America, 5 (10%) Central Africa, 8 (17%) East Africa, 14 (30%) Southern Africa, and 7 (15%) West Africa.ResultsICF using symptom-based screening was performed at 38% of sites; 45% of sites used symptom-screening plus additional diagnostics. IPT at enrollment or ART initiation was implemented in only 17% of sites, with 9% of sites providing IPT to tuberculin-skin-test positive patients. Infection control measures varied: 62% of sites separated smear-positive patients, and healthcare workers used masks at 57% of sites. Only 12 (26%) sites integrated HIV-TB services. Integration was not associated with implementation of TB prevention measures except for IPT provision at enrollment (42% integrated vs. 9% non-integrated; p = 0.03).ConclusionsImplementation of TB screening, IPT provision, and infection control measures was low and variable across regional HIV treatment sites, regardless of integration status. 相似文献
127.
Sebastian Kevany Gertrude Khumalo-Sakutukwa Basant Singh Alfred Chingono Stephen Morin NIMH Project Accept Study Team 《PloS one》2016,11(2)
Background
Provision and scale-up of high quality, evidence-based services is essential for successful international HIV prevention interventions in order to generate and maintain intervention uptake, study integrity and participant trust, from both health service delivery and diplomatic perspectives.Methods
We developed quality assurance (QAC) procedures to evaluate staff fidelity to a cluster-randomized trial of the NIMH Project Accept (HPTN 043) assessing the effectiveness of a community-based voluntary counseling and testing strategy. The intervention was comprised of three components—Mobile Voluntary Counseling and Testing (MVCT), Community Mobilization (CM) and Post-Test Support Services (PTSS). QAC procedures were based on standardized criteria, and were designed to assess both provider skills and adherence to the intervention protocol. Supervisors observed a random sample of 5% to 10% of sessions each month and evaluated staff against multiple criteria on scales of 1–5. A score of 5 indicated 100% adherence, 4 indicated 95% adherence, and 3 indicated 90% adherence. Scores below 3 were considered unsatisfactory, and protocol deviations were discussed with the respective staff.Results
During the first year of the intervention, the mean scores of MVCT and CM staff across the 5 study sites were 4 (95% adherence) or greater and continued to improve over time. Mean QAC scores for the PTSS component were lower and displayed greater fluctuations. Challenges to PTSS staff were identified as coping with the wide range of activities in the PTSS component and the novelty of the PTSS process. QAC fluctuations for PTSS were also associated with new staff hires or changes in staff responsibilities. Through constant staff monitoring and support, by Year 2, QAC scores for PTSS activities had reached those of MVCT and CM.Conclusions
The implementation of a large-sale, evidence based HIV intervention requires extensive QAC to ensure implementation effectiveness. Ongoing appraisal of study staff across sites ensures consistent and high quality delivery of all intervention components, in keeping with the goals of the study protocol, while also providing a forum for corrective feedback, additional supervision and retraining of staff. QAC ensures staff fidelity to study procedures and is critical to the successful delivery of multi-site HIV prevention interventions, as well as the delivery of services scaled up in programmatic situations. 相似文献128.
Christian Pifl Brigitte Plank Wolfgang Wyskovsky Oswald Bertel Gertrude Hellmann Josef Suko 《生物化学与生物物理学报:生物膜》1984,773(2):197-206
Calcium-, calmodulin-dependent phosphorylation of cardiac sarcoplasmic reticulum increases the rate of calcium transport. The complex dependence of calmodulin-dependent phosphoester formation on free calcium and total calmodulin concentrations can be satisfactorily explained by assuming that CaM · (Ca2+)4 is the sole calmodulin-calcium species which activates the calcium-, calmodulin-dependent, membrane-bound protein kinase. The apparent dissociation constant of the E · CaM · (Ca2+)4 complex determined from the calcium dependence of calmodulin-dependent phosphoester formation over a 100-fold range of total calmodulin concentrations (0.01–1 μ M) was 0.9 nM; the respective apparent dissoclation constant at 0.8 mM free calcium, 1 mM free magnesium with low calmodulin concentrations (0.1–50 nM) was 2.60 nM. These results are in good agreement with the apparent dissociation constant of 2.54 nM of high affinity calmodulin binding determined by 125I-labelled calmodulin binding to sarcoplasmic reticulum fractions at 1 mM free calcium, 1 mM free magnesium and total calmodulin concentration ranging from 0.1 to 150 nM, i.e. conditions where approximately 98% of the total calmodulin is present as CaM · (Ca2+)4. The apparent dissociation constant of the calcium-free calmodulin-enzyme complex (E · CaM) is at least 100-fold greater than the apparent dissociation constant of the E · CaM · (Ca2+)4 complex, as judged from non-saturation 125I-labelled calmodulin binding at total calmodulin concentrations of up to 150 nM, in the absence of calcium. 相似文献
129.
The sperm of Luidia clathrata are morphologically typical of asteroid sperm. The head is spherical and contains the nucleus and acrosomal complex. The nucleus has an anterior indentation in which rests the acrosomal complex. There is no evidence of a centriolar fossa along the posterior border of the nucleus. The acrosome is a cup-shaped structure containing a less electron dense central region. The periacrosomal material is homogeneous in nature, and the subacrosomal specialization of the periacrosomal materials appear as bands of varying electron density. The middle piece is an annular band of mitochondria which surrounds the proximal and distal centrioles. The centrioles exhibit the typical nine triplet arrangement. Both the centrioles and the axoneme project to one side of the middle piece region. Associated with the distal centriole is an elaborate pericentriolar process. 相似文献
130.
Eugene F. Roth Herbert Tanowitz Murray Wittner Yoshihiro Ueda Hsin S. Hsieh Gertrude Neumann Ronald L. Nagel 《Experimental parasitology》1981,51(1):116-123
Babesia microti, a protozoan parasite of mammalian erythrocytes was obtained from the blood of an infected human and maintained in golden hamsters, in which a parasitemia of 70% was obtained regularly. The hamsters' response—a subacute, hemolytic anemia—was studied with regard to oxygen affinity and red cell organic phosphate content. In addition, the reduced glutathione status of infected erythrocytes was observed because of the possible importance of this metabolite to parasite growth and red cell integrity. Infected animals developed a severe anemia with reticulocytosis; there occurred a 4-mm decrease in whole blood oxygen affinity without any change in erythrocytes' 2,3-diphosphoglycerate levels. The glutathione content of the infected animals' erythrocytes increased twofold during the course of the infection. In uninfected animals, in which anemia and reticulocytosis had been produced by bleeding, all changes seen in infected animals were reproduced. It was concluded that the changes in the infected animals were due to the anemia and reticulocytosis alone, and that the parasite played no role in these changes apart from being a cause of anemia and reticulocytosis. 相似文献