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   1890篇
  免费   116篇
  国内免费   10篇
耳鼻咽喉   47篇
儿科学   61篇
妇产科学   56篇
基础医学   242篇
口腔科学   85篇
临床医学   126篇
内科学   397篇
皮肤病学   28篇
神经病学   88篇
特种医学   46篇
外科学   320篇
综合类   60篇
预防医学   154篇
眼科学   29篇
药学   186篇
中国医学   23篇
肿瘤学   68篇
  2023年   16篇
  2022年   62篇
  2021年   100篇
  2020年   50篇
  2019年   72篇
  2018年   91篇
  2017年   60篇
  2016年   59篇
  2015年   65篇
  2014年   82篇
  2013年   102篇
  2012年   126篇
  2011年   136篇
  2010年   74篇
  2009年   66篇
  2008年   94篇
  2007年   96篇
  2006年   82篇
  2005年   82篇
  2004年   77篇
  2003年   40篇
  2002年   39篇
  2001年   35篇
  2000年   38篇
  1999年   31篇
  1998年   9篇
  1997年   7篇
  1996年   9篇
  1995年   8篇
  1994年   5篇
  1993年   7篇
  1992年   17篇
  1991年   16篇
  1990年   8篇
  1989年   8篇
  1988年   10篇
  1987年   12篇
  1986年   12篇
  1985年   11篇
  1984年   10篇
  1983年   8篇
  1982年   13篇
  1981年   8篇
  1980年   6篇
  1979年   6篇
  1978年   6篇
  1977年   6篇
  1974年   5篇
  1973年   4篇
  1971年   4篇
排序方式: 共有2016条查询结果,搜索用时 31 毫秒
1.
Coronavirus disease 2019 (COVID-19) has resulted in many challenges in patient care, especially among high-risk populations such as heart transplant recipients. Patients with heart transplant experience a significantly higher mortality rate with COVID-19 infection, and management is based on extrapolation from clinical trials done on nontransplant patients and from clinical experience. Here we report 4 cases of patients with heart transplant who presented with COVID-19 infection in late 2020. Patients presented with symptoms similar to those seen in the general population. All 4 patients were admitted to the hospital, and they were all treated with dexamethasone. In addition, 2 patients received remdesivir. Immunosuppressive medications were adjusted to maintain adequate levels of immunosuppression but at the same time allow for an adequate immune response against the infection. All patients were discharged alive from the hospital. We then performed a literature review on studies that included heart transplant patients who developed the infection and developed suggestions for a standardized management approach, which we share in this article.  相似文献   
2.
3.
Background Despite improving surgical techniques, treatment of heart valve disease in children remains controversial. Somatic growth and adequate anticoagulation are of concern when children undergo valve replacement. We conducted this study to evaluate the performance of valves in this age group. Methods 42 children under the age of 13 years who underwent valve replacement were included in this study. Totally, 50 valves were implanted in 42 patients: 48 were mechanical prostheses, two were bioprosthetic both in pulmonary position. 37 (74%) valves were implanted in mitral position, 10 (20%) in aortic position, 1 (2%) in tricuspid position and 2 (4%) in pulmonary position. Preoperatively, 14 (33,3%) patients were in New York Heart Association (NYHA) class IV, while 27 (64.2%) were in NYHA class III. Results There were 2 (4.7%) hospital deaths and 2 (4.7%) late deaths while 2 (4.7%) patients were lost to follow up. The mean follow up period was 9.4 yrs. 35 (83.3%) patients are in NYHA Class I and free of all medications except warfarin. 3 (7.1%) patients have undergone 5 successful pregnancies. The median INR was 2.23. Major thrombo-embolic episode occurred in 1 (2.3%) patient. Conclusions In view of the problems of sizing, anticoagulation and need for re-operation at an early age, there is a reluctance to replace valves in children. This study shows that despite these problems, valve replacement can be undertaken safely and successfully in children, when repair has failed or not technically feasible.  相似文献   
4.
AIMS: To evaluate the efficacy of culture, histology, CLO-test, Helico-G and Pyloriset tests in diagnosing Helicobacter pylori in the presence or absence of non-steroidal anti-inflammatory drugs (NSAIDs). METHODS: Of 134 patients studied, 75 had taken NSAIDs. At endoscopy, biopsy specimens were taken for culture, histology, and CLO-test. Blood was also taken for enzyme linked immunosorbent assay (ELISA) (Helico-G) and latex agglutination (Pyloriset) tests. RESULTS: The sensitivity, specificity, and predictive values of histology and CLO-test, compared with culture, ranged from 90% to 97%, regardless of NSAID intake. In the 59 patients not taking NSAIDs Helico-G had a sensitivity of 75% (p < 0.05) and a specificity of 61%; Pyloriset's sensitivity and specificity were, respectively, 63% (p < 0.05) and 67%. In the 75 patients taking NSAIDs the sensitivity of Helico-G was 81% and its specificity 45% (p < 0.05); Pyloriset had a sensitivity of 61% (p < 0.05) and a specificity of 50% (p < 0.05). CONCLUSION: These findings suggest that H pylori is more reliably diagnosed by culture, histology, and CLO-test than by the serological tests used in this study, especially in patients treated with NSAIDs.  相似文献   
5.
6.
The calciotropic hormone 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] has been established to control skeletal tissue formation and biomineralization via the regulation of gene expression. This action involves the well-characterized nuclear 1,25(OH)2D3 receptor. However, it has been recognized that several cellular responses to 1,25(OH)2D3 may not to be related to the exclusive nuclear receptor. Indeed, this secosteroid is able to generate rapid responses that have been proposed to be mediated by interactions of the ligand, which is a putative cell membrane-associated rapid-response steroid (MARRS) binding protein for 1,25(OH)2D3 [1,25D3-MARRS]. The nongenomic pathway of 1,25(OH)2D3 was studied here in detail by immunolocalization of the 1,25D3-MARRS during the specific context of human prenatal development. Western blotting with proteins extracted from 4 week- to 27-week-old embryos was performed, evidencing a 65-kDa molecular species recognized by antibody Ab 099 generated against synthetic peptides corresponding to the N terminus of the 1,25D3-MARRS from chick intestinal basolateral membranes. Based on this biochemical conservation of protein in the human species, the temporospatial expression patterns were established in the craniofacial skeleton at the same ages. Comparative analysis was performed in teeth and bones from early morphogenesis to terminal cell differentiation and extracellular biomineralization. The data show the potential implication of 1,25D3-MARRS in the heterogeneous cell population including ameloblasts, odontoblasts, osteoblasts, and osteoclasts. The epithelial-mesenchymal cascade related to odontogenesis was coincident with a sequence of up- and down-regulation of immunoreactive 1,25D3-MARRS. Biomineralization was associated with a striking up-regulation in the adjoining secretory cells in all tissues. Finally, osteoclasts appeared also to express the 1,25D3-MARRS during these early phases of bone modeling. Previously obtained data of the nuclear vitamin D receptor (VDR) expression and this study on 1,25D3-MARRS suggest the existence of cross-talk between the genomic and nongenomic pathways during human development.  相似文献   
7.
Major complications of operations that remove or transplant a portion of the pancreas appear related to the arterial blood supply. Hemorrhage is a result of inadequate control of the appropriate principal arteries, and ischemia and its consequences occur when the arterial blood supply to portions of preserved pancreas has been inadvertently interrupted. This radiographic study of the principal arteries of the pancreas demonstrates that these vessels may be visualized and their origin determined in the vast majority of cases. The application of data gained from preoperative arteriography can potentially decrease the incidence of major complications associated with removal or transplantation of portions of the pancreas.  相似文献   
8.
Marked hypertrophy of the psoas muscle in a bodybuilder produced a unilateral extrinsic mass effect upon the medial cecum and adjacent small bowel. The patient had presented with right lower quadrant pain and leukocytosis. Routine contrast studies of the abdomen were misleading, but a computed tomogram suggested the correct diagnosis.  相似文献   
9.
Age, sex, and handedness effects in foot and eye preferences were studied by questionnaire in large samples of normal adult populations from five different countries (total sample, n = 5064). Foot and eye preference were significantly associated with handedness category (right or left) in all the 10 sex by country samples for foot, and in 9/10 samples for eye. The overall frequencies of crossed preferences were 5% between hand and foot and 19.5% between hand and eye. In right-handers, a gradual shift toward the "right" with increasing age was systematically observed, both for footedness and eyedness. The proportion of crossed hand-foot preference was higher in men than women (7.4% vs 2.5%), and higher in left-handers than right-handers (16.3% vs 4.1%). Sex differences in the proportion of crossed hand-eye preference were variable from one country to the other.  相似文献   
10.
Vaccine-associated paralytic poliomyelitis (VAPP) is a rare complication of oral polio vaccine. We describe a fatal case of VAPP in an 8-month-old boy with Major Histocompatibility Class II deficiency. The isolated poliovirus was a Sabin type 2-type 1 recombinant that showed 1.4% VP1 divergence from Sabin type 2.  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