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   212篇
  免费   47篇
  国内免费   1篇
  2024年   1篇
  2023年   3篇
  2022年   4篇
  2021年   13篇
  2020年   12篇
  2019年   14篇
  2018年   20篇
  2017年   19篇
  2016年   10篇
  2015年   12篇
  2014年   17篇
  2013年   11篇
  2012年   12篇
  2011年   16篇
  2010年   5篇
  2009年   4篇
  2008年   12篇
  2007年   12篇
  2006年   8篇
  2005年   5篇
  2004年   4篇
  2003年   5篇
  2002年   2篇
  2001年   7篇
  2000年   1篇
  1999年   4篇
  1998年   4篇
  1993年   3篇
  1992年   4篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1986年   1篇
  1985年   1篇
  1984年   2篇
  1981年   1篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1972年   1篇
  1971年   1篇
排序方式: 共有260条查询结果,搜索用时 171 毫秒
101.
OBJECTIVE: We investigated the efficacy of early lung cancer screening with low-dose spiral computed tomography(LDCT) in both smokers and nonsmokers based on the current situation of community health service, with integration of superior resources of medical institutions at all levels in Shanghai. METHODS: From August 2013 to August 2014, we screened 11,332 (male 7144; female 4188) high-risk individuals in selected communities of Minhang, Shanghai City, for early diagnosis of lung cancer with LDCT combined with multidisciplinary comprehensive treatment pattern including minimally invasive surgery, exploring the medical service network covering prevention, diagnosis, treatment, rehabilitation, and follow-up. RESULTS: Screening resulted in a diagnosis of cancer in 29 participants. Of these participants, 27 had primary lung cancer, 1 had lung metastatic cancer, and 1 had breast cancer. The detection rate of primary lung cancer was 238.26 cases per 100,000 person-years among all the participants. Specifically, the incidence of primary lung cancer was 336.97 cases per 100,000 person-years among the nonsmoking participants, as compared with 159.06 cases per 100,000 person-years among the smoking participants (P = .054). Among the 27 primary lung cancers, 22 (81.48%) had stage 0 to I lung cancer. CONCLUSION: Based on community health service, screening with LDCT could improve the early diagnosis rate of lung cancer in both smokers and nonsmokers with feasibility and validity, which could be applicable in qualified eligible medical centers and communities in China. It is not reasonable to exclude nonsmokers from screening with LDCT.  相似文献   
102.
应用光学显微镜和电子显微镜技术,研究了中华绒螯蟹(Eriocheir sinensis)胸神经团的神经分泌细胞,描述了其显微和超显微结构。依据细胞形态、细胞核、内分泌颗粒和细胞质的特征将胸神经团神经分泌细胞分为3种类型:Ⅰ型细胞最大,胞质中存在许多大小不同的空泡,分泌颗粒数量很少;Ⅱ型细胞中等大小,细胞器发达,分泌颗粒数量较多,形态多样;Ⅲ型细胞最小,分泌颗粒数量最多,细胞器很少。  相似文献   
103.
Osteoblast-like cell cultures have been established from the marrow of adult rat vertebrae. We have simultaneously examined the response to dexamethasone (dex) treatment in cultures of young adult female vertebral and femoral marrow cells. Alkaline phosphatase (AP) activity was analyzed as well as the expression of mRNAs for osteocalcin (OC) and insulin-like growth factor I (IGF-I). The vertebral and femoral marrow cells were maintained for 7 days in primary culture with or without 10−8 M dex and then 6 days in secondary culture without dex or with 10−8 M or 10−7 M dex. All cells were examined on day 6 of secondary culture. Vertebral and femoral cultures each expressed the highest AP enzyme levels when grown with dex in primary culture (10−8 M) and secondary culture (10−7 M). Under all experimental conditions, vertebral cultures had lower AP enzyme activity than femoral cultures. When dex was omitted from secondary culture, OC gene expression was not detected in either vertebral or femoral passaged cells even if dex was present in primary culture. For dex conditions where OC was expressed, vertebral cultures had higher OC mRNA steady-state levels than femoral cultures. IGF-I gene expression was detected by Northern analysis in both vertebral and femoral secondary cultures. However, vertebral marrow cultures had much higher IGF-I mRNA levels compared to femoral cultures whether or not dex was present in primary culture. These findings demonstrate that dex supports the differentiation of both vertebral and femoral adult marrow osteogenic cells into osteoblasts. Our results support the hypothesis that osteoblastic marrow cultures differ depending upon which location in the skeleton they are from and that there are skeletal site–dependent differences in the insulin-like growth factor system components. J. Cell. Biochem. 71:382–391, 1998. © 1998 Wiley-Liss, Inc.  相似文献   
104.
We have already identified central neurons for cardioinhibition and cardioacceleration in Bathynomus, an isopod crustacean. The 1st thoracic ganglion (TG1) has cardioinhibitory neurons, which we call CIs, while the 2nd and 3rd thoracic ganglia (TG2 and TG3) have cardioacceleratory neurons, which we call CA1s and CA2s. We examined neuronal pathways for cardioinhibitory reflexes in whole animal preparations, using intracellular and extracellular recording methods. Cardiac inhibition in response to a variety of external stimuli was mediated by activation of CIs and inhibition of both CAs. When preparations had the ventral nerve cord intact, CIs were activated by excitatory postsynaptic potentials and CAs were inhibited by inhibitory postsynaptic potentials in response to tactile stimuli applied to sensilla setae on appendages and afferent stimuli applied to ganglionic roots of the thoracic ganglia. However, stimulation of ganglionic nerve roots of TG2 and TG3, or tactile stimulation of the body surface, failed to evoke inhibition of CAs in preparations in which both the cerebral ganglion and TG1 had been excised. These results suggest that TG1 is an indispensable central region for the excitation of CI and for inhibition of CA neurons, induced by tactile stimuli and by stimuli applied to nerve roots of TG2 and TG3.  相似文献   
105.
Surgery is the gold therapeutic standard for patients affected with stage I non-small cell lung cancer. Stereotactic ablative radiotherapy is currently considered the preferred treatment option for inoperable patients, representing approximately 25%. Limited data are available directly comparing surgery and SABR in operable patients, none of them prospective. Preliminary results are encouraging, showing that the two treatment modalities are equally effective in terms of tumour control, with expected similar survival projections. Moreover, in elderly patients SABR could represent a valid treatment alternative in comparison to surgery due to the lower morbidity. We here review and discuss the potential role of SABR as an alternative to surgery in operable early stage lung cancer patients.  相似文献   
106.
s sp. nov. (Reptilia sp. nov. (Reptilia, Serpentes, Simoliopheidae) is described from the Upper Cretaceous ‘unnamed’ beds of the Mizdah Formation (Santonian-Campanian) at Draa Ubari in western Libya. The accompanying fauna consists of an undetermined mammal represented by a caudal vertebra, of hybodontoid, ganopristid and lamnoid sharks, as well as dipnoans, lepisosteids, pycnodonts, enchodontids, turtles, crocodiles and ?dinosaurs.

Résumé

Une nouvelle localité de serpents, mammifères et autres vertébrés du Crétacé supérieur en Afrique (Libye occidentale). s sp. nov. (Reptilia sp. nov. (Reptilia, Serpentes, Simoliopheidae) est décrit dans des grès de la formation Mizdah (Santonien-Campanien), à Draa Ubari en Libye occidentale. Les mêmes couches ont livré une vertèbre caudale de mammifère indéterminé, ainsi que des restes de requins hybodontoïdes, ganopristidés et lamnoïdes, de dipneustes, lépisostéïdes, pycnodontes, enchodontidés, tortues, crocodiles et? dinosaures.  相似文献   
107.
Summary In Locusta migratoria, the major pathway from descending deviation detectors (DDNs; preceding paper, Hensler 1992) to wing motoneurons involves a population of thoracic interneurons (TINs). Nine TINs are characterized which receive input from cervical proprioreceptors. Responses to the combination of exteroreceptive input (signalling course deviation) and proprioreceptive input (monitoring movement and position of the head) are described and compared to those of DDNs to the same stimuli.Abbreviations AP action potential - DDN descending deviation detector neuron - TCG tritocerebral giant neuron - TIN thoracic interneuron  相似文献   
108.
The fifth lumbar vertebra, like the other units of the lumbar spine, shows a significant trend toward lowering and broadening of the body with age. In most individuals the pedicales of L5 arise from the lateral surface of the body, rather than posteriorly as in the other lumbar vertebrae, and the increase in body breadth is very often associated with the formation of reinforcing columns of bone between the bases of the pedicles and osteophytes bordering the inferior endplate. In L5 midbody breadth shows a greater gain than endplate breadths, so "flaring" is decreased with age, a change that is statistically significant in Black males and White females. This vertebra shows no significant change in endplate biconcavity or posterior wedging with age.  相似文献   
109.
Minimally invasive surgeries aiming to restore fractured vertebral body are increasing; therefore, our goals were to create a 3D vertebra reconstruction process and design clinical indices to assess the vertebral restoration in terms of heights, angles and volumes. Based on computed tomography (CT)-scan of the vertebral spine, a 3D reconstruction method as well as relevant clinical indices were developed. First, a vertebra initial solution requiring 5 min of manual adjustments is built. Then an image processing algorithm places this solution in the CT-scan images volume to adjust the model's nodes. On the vertebral body's anterior and posterior parts, nine robust heights, volume and endplate angle measurement methods were developed. These parameters were evaluated by reproducibility and accuracy studies. The vertebral body reconstruction accuracy was 1.0 mm; heights and volume accuracy were, respectively, 1.2 and 179 mm3. In conclusion, a 3D vertebra reconstruction process requiring little user time was proposed as well as 3D clinical indices assessing fractured and restored vertebra.  相似文献   
110.
A quantitative study of morphological and histological changes in the skeleton (cranial bones and vertebrae) of adult Atlantic salmon Salmo salar during its anadromous migration was performed in order to specify various aspects of its skeletal biology in relationship to this migration. At the beginning of the ascent, there was no morphological difference in the cranial bones between males and females. As the spawning season approached, males showed marked secondary sexual characters particularly allometric breeding growth of some bones of the skull. The histological analysis of the vertebral bone tissue along the vertebral axis showed that bone compacity and number of trabeculae vary depending on their localization on the vertebral axis. Moreover, bone compacity decreased significantly with the sexual maturation of the fish whereas the number of trabeculae grew in both sexes. Thus, the vertebrae (like scales) represent an important source of calcium and other elements during anadromous migration in Atlantic salmon.  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