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   120篇
  免费   8篇
耳鼻咽喉   2篇
妇产科学   14篇
基础医学   22篇
口腔科学   6篇
临床医学   6篇
内科学   7篇
神经病学   8篇
特种医学   4篇
外科学   10篇
综合类   3篇
预防医学   7篇
眼科学   21篇
药学   2篇
肿瘤学   16篇
  2022年   1篇
  2021年   7篇
  2020年   1篇
  2019年   6篇
  2018年   6篇
  2016年   4篇
  2015年   1篇
  2014年   2篇
  2013年   2篇
  2012年   2篇
  2011年   3篇
  2010年   3篇
  2009年   3篇
  2008年   8篇
  2007年   6篇
  2006年   6篇
  2005年   5篇
  2004年   4篇
  2003年   3篇
  2002年   2篇
  2001年   3篇
  2000年   6篇
  1999年   2篇
  1998年   3篇
  1997年   1篇
  1995年   1篇
  1993年   1篇
  1992年   1篇
  1991年   2篇
  1989年   2篇
  1988年   2篇
  1987年   2篇
  1986年   1篇
  1985年   2篇
  1984年   3篇
  1983年   4篇
  1979年   2篇
  1978年   2篇
  1975年   1篇
  1973年   5篇
  1972年   2篇
  1970年   1篇
  1966年   1篇
  1963年   1篇
  1947年   1篇
  1937年   1篇
排序方式: 共有128条查询结果,搜索用时 0 毫秒
81.
This study provides a histologic examination of twelve cans of beef dog food and assesses the contents of each brand. Two random samples from each of twelve cans of beef dog food were formalin-fixed, paraffin-embedded, sectioned at 4 microns, and stained with hematoxylin and eosin. The percentage of meat content (defined as skeletal muscle content) was estimated by superimposing a grid over photomicrographs (n = 7 each sample); the number of grid line intersections overlying skeletal muscle tissue (meat) was recorded and used to determine an estimate of the meat content. The percentage of meat content ranged from 0.2 to 13.6% (median 1.3%). There was no correlation between meat content and the calculated cost per ounce of food (range $0.04–$0.47; median $0.15). In the brands examined, a relatively small portion of the contents of canned beef dog food comprised meat, despite the labeling which advertised ‘beef’ on each can. There was no correlation between cost and the estimated meat content. A variety of other tissue types were variably identified in the sampled food, including connective tissue, blood vessels, bone, cartilage, lung, peripheral nerve, skin, adipose tissue, and rarely other solid organs such as kidney and pancreas.  相似文献   
82.
Waterfowl are considered the natural reservoir of low-virulence Newcastle disease viruses (loNDVs) and low-pathogenic avian influenza viruses (LPAIVs). The objective of this study was to investigate the effect of co-infections with loNDV and LPAIV on the infectivity and excretion of these viruses in mallards. One-month-old mallards were inoculated intranasally with 106 median embryo infectious doses of a wild-bird-origin loNDV and A/Mallard/MN/199106/99 (H3N8) LPAIV on the same day or received the LPAIV 2 or 5 days after loNDV inoculation. All mallards became infected with both viruses based on detection of seroconversion and viral shedding. Co-infection resulted in a higher number of cloacal swabs detected positive for LPAIV and a lower number of cloacal swabs detected positive for loNDV in some groups, although differences between groups were not statistically significant. Co-infection did not affect replication of LPAIV in epithelial cells of the lower intestine and bursa of Fabricius. In summary, the results of this study indicate that co-infection with LPAIV and loNDV does not affect the ability of mallards to be infected with either virus although it may have minimal effects on patterns (source and timing) of viral shedding.  相似文献   
83.
For investigation of the pathogenicity of lentivirus strains, which have distinctly different cytopathic phenotypes in synovial membrane cell culture, plaque-purified, lytic, and nonlytic ovine lentivirus (OvLV) isolates were inoculated intratracheally into two groups of neonatal lambs. Twelve lambs were inoculated with a lytic OvLV isolate and 3 lambs each with two nonlytic OvLV isolates. Five control lambs were inoculated with either virus-free medium or were left uninoculated. In 8 of 12 lambs inoculated with a lytic OvLV isolate mild to severe lesions of lymphoid interstitial pneumonia (LIP) and pulmonary lymphoid hyperplasia developed, 6 of 12 lambs had lesions of pulmonary lymph node follicular hyperplasia, 3 of 9 female lambs had lesions of lymphoproliferative mastitis, 3 of 10 lambs had lesions of lymphocytic/plasmacytic synovitis, and 3 lambs had no lesions. In 3 of 6 lambs inoculated with nonlytic OvLV isolates only mild LIP lesions developed, without concurrent mammary gland or joint lesions. Bronchoalveolar lavage samples from OvLV-diseased lambs contained on average 1.5-fold more numbers of total leukocytes, and 4-fold more numbers of lymphocytes, compared with bronchoalveolar lavage samples of normal lambs. Monoclonal antibodies to ovine lymphocyte surface markers showed that the SBU-T8+ lymphocyte (CD 8 equivalent) was the predominant lymphocyte subset (mean of 65% of total lavaged lymphocytes) in bronchoalveolar lavage samples of 3 diseased lambs. Ovine lentivirus was reisolated from multiple tissues of both groups of OvLV-inoculated lambs, but the percentage of individual tissues infected was greater in lambs inoculated with the lytic viral isolate. Control lambs had no lesions and failed to produce OvLV-specific antibodies or yield OvLV from tissues. All OvLV-inoculated lambs produced either low or undetectable serum virus neutralizing antibodies. In contrast, lambs inoculated with either lytic or nonlytic OvLV produced precipitating antibodies to OvLV glycoprotein and group-specific protein. However, initial detection of precipitating antibodies to OvLV glycoprotein was earlier (mean, 5.8 weeks after inoculation) in OvLV-infected lambs in which severe lymphoproliferative disease developed and delayed (mean, 10.2 weeks after inoculation) in OvLV-infected lambs with mild or no lesions. Together, these results suggest that lentivirus isolates produced disease in a virus strain-dependent manner and suggest that humoral immune responses against OvLV failed to prevent lesion development in lentivirus-infected lambs.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
84.
Children with autism have deficits in social interaction, including the failure to engage in sharing responses. Four children with autism were taught a sharing response chain. The treatment package (manual guidance, auditory prompts, and contingent access to toy play and social interaction with the recipient instructor) was introduced successively across participants in a multiple-baseline design. None of the participants engaged in the sharing response chain during baseline. Systematic increases in responding occurred for all four participants in the presence of training stimuli. In addition, there were systematic increases in responding to non-trained probe stimuli. Also, during pre- and post-test measures, the participants demonstrated sharing in the presence of peers in a non-training classroom containing non-trained toys. Furthermore, social validity measures indicated that judges scored more post-treatment responses than baseline responses as “sharing.”  相似文献   
85.
We describe the clinical findings in two patients with double heterozygosity, both involving Stickler syndrome. In case 1, the proposita had Albright hereditary osteodystrophy which was inherited from her mother and type 1 Stickler syndrome which was a new mutation. The combination of manifestations from the two syndromes had resulted in initial diagnostic confusion. Diagnosis of the latter syndrome was made only following ophthalmic examination which documented the presence of a membranous vitreous anomaly characteristic of type 1 Stickler syndrome. Subsequent confirmation was achieved by mutation analysis of the COL2A1 gene. The propositus in case 2 inherited Treacher Collins syndrome paternally and type 2 Stickler syndrome maternally. The overlap of facial anomalies may have resulted in a more severe phenotype for the patient. The diagnosis of Stickler syndrome in the propositus was confirmed initially by vitreous assessment and later by demonstration of mutation in the COL11A1 gene. These two patients highlight the key role of vitreous examination and vitreoretinal phenotyping in the differential diagnosis of Stickler syndrome and its subtypes in cases where the clinical picture is complicated by double heterozygosity.  相似文献   
86.

Background

High failure rates of femoropopliteal artery (FPA) interventions are often attributed in part to severe mechanical deformations that occur with limb movement. Axial compression and bending of the FPA likely play significant roles in FPA disease development and reconstruction failure, but these deformations are poorly characterized. The goal of this study was to quantify axial compression and bending of human FPAs that are placed in positions commonly assumed during the normal course of daily activities.

Methods

Retrievable nitinol markers were deployed using a custom-made catheter system into 28 in situ FPAs of 14 human cadavers. Contrast-enhanced, thin-section computed tomography images were acquired with each limb in the standing (180 degrees), walking (110 degrees), sitting (90 degrees), and gardening (60 degrees) postures. Image segmentation and analysis allowed relative comparison of spatial locations of each intra-arterial marker to determine axial compression and bending using the arterial centerlines.

Results

Axial compression in the popliteal artery (PA) was greater than in the proximal superficial femoral artery (SFA) or the adductor hiatus (AH) segments in all postures (P = .02). Average compression in the SFA, AH, and PA ranged from 9% to 15%, 11% to 19%, and 13% to 25%, respectively. The FPA experienced significantly more acute bending in the AH and PA segments compared with the proximal SFA (P < .05) in all postures. In the walking, sitting, and gardening postures, average sphere radii in the SFA, AH, and PA ranged from 21 to 27 mm, 10 to 18 mm, and 8 to 19 mm, whereas bending angles ranged from 150 to 157 degrees, 136 to 147 degrees, and 137 to 148 degrees, respectively.

Conclusions

The FPA experiences significant axial compression and bending during limb flexion that occur at even modest limb angles. Moreover, different segments of the FPA appear to undergo significantly different degrees of deformation. Understanding the effects of limb flexion on axial compression and bending might assist with reconstructive device selection for patients requiring peripheral arterial disease intervention and may also help guide the development of devices with improved characteristics that can better adapt to the dynamic environment of the lower extremity vasculature.  相似文献   
87.
88.
89.
90.
Argon laser therapy of endometriosis: a review of 92 consecutive patients   总被引:1,自引:0,他引:1  
The conception rate, relief of pain, and safety of argon laser photocoagulation of endometriosis were evaluated in 92 patients. All patients were treated at the time of diagnosis with the argon laser delivered through a flexible quartz fiber passed through the operating channel of a standard and unmodified laparoscope. The uncorrected pregnancy rate was 34% (19 of 56), with 64% of the pregnancies occurring within 6 months of therapy. The conception rate was slightly greater in women with infertility of 24 months or less and in women without other fertility factors. Ninety-two percent of 50 women with pelvic pain reported a reduction of their pain after treatment. The argon laser is an effective, simple, and safe alternative for the treatment of mild or moderate endometriosis.  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