全文获取类型
收费全文 | 643篇 |
免费 | 68篇 |
国内免费 | 2篇 |
专业分类
儿科学 | 24篇 |
妇产科学 | 9篇 |
基础医学 | 132篇 |
口腔科学 | 9篇 |
临床医学 | 68篇 |
内科学 | 118篇 |
皮肤病学 | 3篇 |
神经病学 | 43篇 |
特种医学 | 101篇 |
外科学 | 69篇 |
综合类 | 12篇 |
预防医学 | 66篇 |
眼科学 | 2篇 |
药学 | 36篇 |
肿瘤学 | 21篇 |
出版年
2022年 | 4篇 |
2021年 | 13篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 9篇 |
2017年 | 12篇 |
2016年 | 11篇 |
2015年 | 9篇 |
2014年 | 13篇 |
2013年 | 20篇 |
2012年 | 19篇 |
2011年 | 25篇 |
2010年 | 20篇 |
2009年 | 21篇 |
2008年 | 22篇 |
2007年 | 37篇 |
2006年 | 20篇 |
2005年 | 26篇 |
2004年 | 20篇 |
2003年 | 21篇 |
2002年 | 16篇 |
2001年 | 11篇 |
2000年 | 14篇 |
1999年 | 18篇 |
1998年 | 14篇 |
1997年 | 19篇 |
1996年 | 17篇 |
1995年 | 8篇 |
1994年 | 13篇 |
1993年 | 10篇 |
1992年 | 20篇 |
1991年 | 12篇 |
1990年 | 12篇 |
1989年 | 12篇 |
1988年 | 14篇 |
1987年 | 20篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 10篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 15篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1976年 | 11篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1967年 | 4篇 |
排序方式: 共有713条查询结果,搜索用时 15 毫秒
11.
Evaluation of the Staph-Zym system with staphylococci isolated from bovine intramammary infections 总被引:1,自引:1,他引:1
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A total of 148 staphylococci isolated from bovine intramammary infections were used to evaluate the Staph-Zym system (ROSCO, Taastrup, Denmark). The overall accuracy of the system was 91.9%. The system correctly identified all strains of Staphylococcus aureus, Staphylococcus simulans, and Staphylococcus xylosus and 95% of Staphylococcus intermedius strains. Of 33 Staphylococcus hyicus strains, 31 (93.9%) were classified correctly by the Staph-Zym system, as well as 8 (80%) of 10 Staphylococcus chromogenes strains. All 11 Staphylococcus epidermidis strains and the 1 Staphylococcus haemolyticus strain included in the study were identified, but the Staph-Zym system had difficulty distinguishing strains of Staphylococcus warneri and Staphylococcus hominis from other species in the S. epidermidis group. The Staph-Zym system correctly identified all six S. xylosus strains and two of three Staphyloccus sciuri strains. The Staph-Zym system was considered an acceptable alternative to conventional methods for identification of bovine mammary gland isolates. 相似文献
12.
Mahadevaiah SK; Odorisio T; Elliott DJ; Rattigan A; Szot M; Laval SH; Washburn LL; McCarrey JR; Cattanach BM; Lovell-Badge R; Burgoyne PS 《Human molecular genetics》1998,7(4):715-727
An RNA-binding motif (RBM) gene family has been identified on the human Y
chromosome that maps to the same deletion interval as the 'azoospermia
factor' (AZF). We have identified the homologous gene family (Rbm) on the
mouse Y with a view to investigating the proposal that this gene family
plays a role in spermatogenesis. At least 25 and probably >50 copies of
Rbm are present on the mouse Y chromosome short arm located between Sry and
the centromere. As in the human, a role in spermatogenesis is indicated by
a germ cell-specific pattern of expression in the testis, but there are
distinct differences in the pattern of expression between the two species.
Mice carrying the deletion Yd1, that maps to the proximal Y short arm, are
female due to a position effect resulting in non-expression of Sry ;
sex-reversing such mice with an Sry transgene produces males with a high
incidence of abnormal sperm, making this the third deletion interval on the
mouse Y that affects some aspect of spermatogenesis. Most of the copies of
Rbm map to this deletion interval, and the Yd1males have markedly reduced
Rbm expression, suggesting that RBM deficiency may be responsible for, or
contribute to, the abnormal sperm development. In man, deletion of the
functional copies of RBM is associated with meiotic arrest rather than
sperm anomalies; however, the different effects of deletion are consistent
with the differences in expression between the two species.
相似文献
13.
M R Recktenwald J A Hodgson R R Roy S Riazanski G E McCall I Kozlovskaya D A Washburn J W Fanton V R Edgerton 《Journal of neurophysiology》1999,81(5):2451-2463
Effects of spaceflight on Rhesus quadrupedal locomotion after return to 1G. Locomotor performance, activation patterns of the soleus (Sol), medial gastrocnemius (MG), vastus lateralis (VL), and tibialis anterior (TA) and MG tendon force during quadrupedal stepping were studied in adult Rhesus before and after 14 days of either spaceflight (n = 2) or flight simulation at 1G (n = 3). Flight simulation involved duplication of the spaceflight conditions and experimental protocol in a 1G environment. Postflight, but not postsimulation, electromyographic (EMG) recordings revealed clonus-like activity in all muscles. Compared with preflight, the cycle period and burst durations of the primary extensors (Sol, MG, and VL) tended to decrease postflight. These decreases were associated with shorter steps. The flexor (TA) EMG burst duration postflight was similar to preflight, whereas the burst amplitude was elevated. Consequently, the Sol:TA and MG:TA EMG amplitude ratios were lower following flight, reflecting a "flexor bias." Together, these alterations in mean EMG amplitudes reflect differential adaptations in motor-unit recruitment patterns of flexors and extensors as well as fast and slow motor pools. Shorter cycle period and burst durations persisted throughout the 20-day postflight testing period, whereas mean EMG returned to preflight levels by 17 days postflight. Compared with presimulation, the simulation group showed slight increases in the cycle period and burst durations of all muscles. Mean EMG amplitude decreased in the Sol, increased in the MG and VL, and was unchanged in the TA. Thus adaptations observed postsimulation were different from those observed postflight, indicating that there was a response unique to the microgravity environment, i.e., the modulations in the nervous system controlling locomotion cannot merely be attributed to restriction of movement but appear to be the result of changes in the interpretation of load-related proprioceptive feedback to the nervous system. Peak MG tendon force amplitudes were approximately two times greater post- compared with preflight or presimulation. Adaptations in tendon force and EMG amplitude ratios indicate that the nervous system undergoes a reorganization of the recruitment patterns biased toward an increased recruitment of fast versus slow motor units and flexor versus extensor muscles. Combined, these data indicate that some details of the control of motor pools during locomotion are dependent on the persistence of Earth's gravitational environment. 相似文献
14.
The role of size, sequence and haplotype in the stability of FRAXA and FRAXE alleles during transmission 总被引:2,自引:5,他引:2
Murray A; Macpherson JN; Pound MC; Sharrock A; Youings SA; Dennis NR; McKechnie N; Linehan P; Morton NE; Jacobs PA 《Human molecular genetics》1997,6(2):173-184
Factors involved in the stability of trinucleotide repeats during
transmission were studied in 139 families in which a full mutation,
premutation or intermediate allele at either FRAXA or FRAXE was
segregating. The transmission of alleles at FRAXA, FRAXE and four
microsatellite loci were recorded for all individuals. Instability within
the minimal and common ranges (0-40 repeats for FRAXA, 0-30 repeats for
FRAXE) was extremely rare; only one example was observed, an increased in
size at FRAXA from 29 to 39 repeats. Four FRAXA and three FRAXE alleles in
the intermediate range (41-60) repeats for FRAXA, 31-60 for FRAXE) were
unstably transmitted. Instability was more frequent for FRAXA intermediate
alleles that had a tract of pure CGG greater than 37 although instability
only occurred in two of 13 such transmissions: the changes observed were
limited to only one or two repeats. Premutation FRAXA alleles over 100
repeats expanded to a full mutation during female transmission in 100% of
cases, in agreement with other published series. There was no clear
correlation between haplotype and probability of expansion of FRAXA
premutations. Instability at FRAXA or FRAXE was more often observed in
conjunction with a second instability at an independent locus suggesting
genomic instability as a possible mechanism by which at least some FRAXA
and FRAXE mutations arise.
相似文献
15.
16.
Physical Activity Scale for the Elderly (PASE): the relationship with activity measured by a portable accelerometer 总被引:5,自引:0,他引:5
BACKGROUND: The purpose of this study was to examine the validity of the Physical Activity Scale for the Elderly (PASE) by comparing PASE scores with physical activity assessed by a portable accelerometer. METHODS: Experimental design: Correlational-mean activity level over a 3-day period was correlated with PASE scores. Setting: Physical activity of participants was monitored over 3 days during normal daily activity. Participants: Twenty healthy adult volunteers, 67-80 years of age, participated in this study. Measures: Physical activity from 09:00 to 21:00 hours was assessed over 3 consecutive weekdays (Wednesday-Friday) using a Computer Science and Applications, Inc. (CSA) portable accelerometer. Following completion of the 3-day monitoring period physical activity was assessed with the PASE. RESULTS: PASE scores were significantly correlated with average 3-day CSA readings (r = 0.49, p < 0.05) in the total sample and in those over age 70 years (r = 0.64, p < 0.5). CONCLUSIONS: These results add to the literature supporting the validity of the PASE as a measure of physical activity in older individuals. 相似文献
17.
The palpation and enucleation of occult insulinomas (less than 15 mm) can be a difficult surgical problem even with good arteriographic localization. In the authors' limited experience, confirmation of arteriographic findings by pancreatic venous sampling provided little additional localizing information. However, if arteriography is negative or equivocal, venous sampling can indicate the segment of pancreas to be "blindly" resected if the adenoma is not palpable. Venous sampling may be misleading in polyendocrine syndromes because of the frequency of multiple adenomas and variable hormone production. 相似文献
18.
S-A Ivarsson D Bergqvist NR Lundström E Maly KO Nilsson C Wattsgård 《Acta paediatrica (Oslo, Norway : 1992)》1992,81(12):1044-1048
We report a case of Takayasu's disease with severe renovascular hypertension in a girl from Eritrea. In the "burn-out" phase after the erythrocyte sedimentation rate had normalized, reconstructive vascular surgery was performed as further progression of the disease seemed unlikely. However, probably due to her growth, the graft rotated and a second operation was successfully performed. 相似文献
19.
JJ Rangasami DC Greenwood B McSporran PJ Smail CC Patterson NR Waugh 《Archives of disease in childhood》1997,77(3):210-213
OBJECTIVES: To calculate the incidence of type 1 diabetes in Scottish children aged less than 15 years between 1984 and 1993; to examine changes in incidence; and to calculate the prevalence of diabetes at the end of this period. DESIGN: Three data sources were used to construct the Scottish Study Group for the Care of Young Diabetics register: active reporting of all new cases; reports from the Scottish Morbidity Register 1; and local registers. SUBJECTS: All children resident in Scotland diagnosed with primary insulin dependent diabetes mellitus when less than 15 years of age between 1984 and 1993. MAIN OUTCOME MEASURES: Annual incidence and prevalence rate for Scotland; time trend in incidence over the 10 years; differences in incidence between the three different age groups; and completeness of the register. RESULTS: The average annual incidence for Scotland was 23.9/100,000 children. The prevalence rate was 1.5/1000 in 1993. A total of 2326 cases was identified from the three sources. Capture-recapture analysis suggests a case ascertainment of 98.6%. The annual incidence rates increased at a rate of 2% each year (rate ratio = 1.02, 95% confidence interval (CI) 1.01 to 1.03). The incidence was higher in boys than girls (rate ratio = 1.08, 95% CI 1.00 to 1.18), and the incidence rates increased with age: 15.3/100,000/year for age 0-4 years, 24.4/ 100,000/year for age 5-9 years, and 31.9/ 100,000/year for age 10-14 years. CONCLUSIONS: The incidence of type 1 diabetes in Scotland is increasing and the prevalence is relatively high. These findings have important implications for health service resource allocation. The Scottish Study Group for the Care of Young Diabetics' register provides a base for monitoring and research. 相似文献
20.
Washburn PV 《Hospital topics》2000,78(4):5-8
There are a variety of ways to improve patient education. Healthcare managers should investigate the best practices used by the most successful providers and adapt the best ideas for use in their own organizations. Healthcare providers are increasingly recognizing that developing an effective system of patient education is one of the most cost-effective ways to maintain the health status of chronically ill patients. In an era of capitated payment and competition, the provider who can successfully partner with its patients to manage their health will be the one to survive. 相似文献