首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   385篇
  免费   41篇
耳鼻咽喉   2篇
儿科学   27篇
妇产科学   1篇
基础医学   52篇
口腔科学   29篇
临床医学   37篇
内科学   83篇
皮肤病学   10篇
神经病学   15篇
特种医学   61篇
外科学   40篇
综合类   11篇
预防医学   39篇
眼科学   1篇
药学   11篇
肿瘤学   7篇
  2018年   5篇
  2017年   3篇
  2016年   7篇
  2015年   3篇
  2014年   6篇
  2013年   5篇
  2012年   8篇
  2011年   11篇
  2010年   11篇
  2009年   18篇
  2008年   15篇
  2007年   11篇
  2006年   12篇
  2005年   8篇
  2004年   13篇
  2003年   6篇
  2002年   8篇
  2001年   6篇
  2000年   9篇
  1999年   15篇
  1998年   11篇
  1997年   16篇
  1996年   12篇
  1995年   6篇
  1994年   9篇
  1993年   9篇
  1992年   9篇
  1991年   8篇
  1990年   8篇
  1989年   13篇
  1988年   13篇
  1987年   9篇
  1986年   11篇
  1985年   9篇
  1984年   9篇
  1983年   5篇
  1982年   5篇
  1981年   7篇
  1980年   11篇
  1979年   4篇
  1978年   4篇
  1977年   8篇
  1976年   7篇
  1975年   8篇
  1974年   5篇
  1973年   4篇
  1972年   4篇
  1970年   6篇
  1968年   3篇
  1966年   2篇
排序方式: 共有426条查询结果,搜索用时 31 毫秒
1.
2.
Pediatric knee MR imaging: pattern of injuries in the immature skeleton   总被引:3,自引:0,他引:3  
  相似文献   
3.
The present study was undertaken to assess the temporal association between the profiles of serum concentrations of oestradiol-17beta, progesterone, chorionic gonadotrophin (CG) and relaxin in pregnancies established naturally, and after embryo transfer, as well as in failed pregnancies in rhesus monkeys. In naturally mated cycles (group 1) a conception rate of 75% was obtained. In group 1, the mean day of CG detection in serum was 11.5 +/- 1.9 day post-ovulation, and for relaxin, 9.0 +/- 2.5 day post-ovulation. In group 2, embryo transfer to synchronous, non-mated surrogate recipients was performed; seven embryo transfer cycles yielded three pregnancies which were allowed to continue to term and normal infants were delivered. In embryo transfer cycles the mean day of CG detection was 14.8 +/- 1.8 day post- ovulation, and for relaxin, 11.4 +/- 2.6 day post-ovulation. A delay of about 3 days was observed in the appearance in circulation of CG (P < 0.05) and also of relaxin (P < 0.05) between natural mated and embryo transfer conception cycles. Significant differences (P < 0.05 for progesterone and P < 0.03 for oestradiol) were obtained for the areas under the curves for progesterone and oestradiol between days 12 and 16 in conception cycles compared with failed pregnancies. These data provide the first observation of the normal hormonal signals associated with maternal recognition of transferred embryos during the peri- implantation period, and suggest that the use of such an experimental primate embryo transfer model may help to elucidate components of maternal and embryonic signal-response mechanisms during embryo implantation.   相似文献   
4.
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   
5.
6.
Doppman  JL; Brennan  MF; Dunnick  NR; Kahn  CR; Gorden  P 《Radiology》1981,138(3):557-562
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   
7.
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   
8.
This study tested the hypothesis that hypothalamic noradrenaline (NA) depletion induced by 6-hydroxydopamine alters neuroendocrine, but not behavioural, responses to aversive stimuli. Sham-operated and NA depleted rats were exposed to pairings of an auditory (clicker) CS and (footshock) US in a distinctive environment. Subjects were tested for preference of a 'safe' environment over the one in which they were shocked, as a measure of effective conditioning to the contextual stimuli present in the distinctive environment. Subjects were also tested, in a separate operant chamber, for the suppression of drinking in the presence of the auditory stimulus, as a measure of effective conditioning to the explicit auditory CS. Blood samples were collected immediately following each phase of the behavioural experiment and were later analysed for plasma Corticosterone concentration. Behavioural and Corticosterone responses of individual control animals to the CS were positively correlated, consistent with previous results. This correlation was not present in the NA depleted group. The lesioned rats also showed a severely attenuated Corticosterone response to the footshock US. By contrast, NA depletion had no effect on any behavioural measure of CS or contextual conditioning. Together with previous experiments, these results suggest that diencephalic NA projections are more likely to mediate neuroendocrine, and coeruleo-cortical NA projections are more likely to mediate behavioural responses to conditioned and unconditioned aversive stimuli.  相似文献   
9.
10.
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   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号