全文获取类型
收费全文 | 2076篇 |
免费 | 118篇 |
国内免费 | 76篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 172篇 |
妇产科学 | 32篇 |
基础医学 | 242篇 |
口腔科学 | 59篇 |
临床医学 | 270篇 |
内科学 | 519篇 |
皮肤病学 | 73篇 |
神经病学 | 65篇 |
特种医学 | 391篇 |
外科学 | 91篇 |
综合类 | 44篇 |
预防医学 | 90篇 |
眼科学 | 21篇 |
药学 | 89篇 |
2篇 | |
肿瘤学 | 109篇 |
出版年
2023年 | 6篇 |
2022年 | 7篇 |
2021年 | 11篇 |
2020年 | 14篇 |
2019年 | 16篇 |
2018年 | 31篇 |
2017年 | 24篇 |
2016年 | 22篇 |
2015年 | 39篇 |
2014年 | 48篇 |
2013年 | 58篇 |
2012年 | 34篇 |
2011年 | 38篇 |
2010年 | 88篇 |
2009年 | 84篇 |
2008年 | 52篇 |
2007年 | 91篇 |
2006年 | 53篇 |
2005年 | 56篇 |
2004年 | 29篇 |
2003年 | 26篇 |
2002年 | 32篇 |
2001年 | 42篇 |
2000年 | 31篇 |
1999年 | 31篇 |
1998年 | 133篇 |
1997年 | 157篇 |
1996年 | 133篇 |
1995年 | 108篇 |
1994年 | 115篇 |
1993年 | 97篇 |
1992年 | 28篇 |
1991年 | 37篇 |
1990年 | 40篇 |
1989年 | 55篇 |
1988年 | 47篇 |
1987年 | 43篇 |
1986年 | 50篇 |
1985年 | 50篇 |
1984年 | 28篇 |
1983年 | 17篇 |
1982年 | 24篇 |
1981年 | 31篇 |
1980年 | 25篇 |
1979年 | 4篇 |
1978年 | 8篇 |
1977年 | 18篇 |
1976年 | 25篇 |
1975年 | 16篇 |
1970年 | 3篇 |
排序方式: 共有2270条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
Erwin M Speklé Judith Heinrich Marco JM Hoozemans Birgitte M Blatter Allard J van der Beek Jaap H van Dieën Maurits W van Tulder 《BMC musculoskeletal disorders》2010,11(1):259
Background
The costs of arm, shoulder and neck symptoms are high. In order to decrease these costs employers implement interventions aimed at reducing these symptoms. One frequently used intervention is the RSI QuickScan intervention programme. It establishes a risk profile of the target population and subsequently advises interventions following a decision tree based on that risk profile. The purpose of this study was to perform an economic evaluation, from both the societal and companies' perspective, of the RSI QuickScan intervention programme for computer workers. In this study, effectiveness was defined at three levels: exposure to risk factors, prevalence of arm, shoulder and neck symptoms, and days of sick leave. 相似文献35.
36.
The ileoanal J pouch: radiographic evaluation 总被引:1,自引:0,他引:1
Endorectal ileoanal pull-through offers an attractive alternative to proctocolectomy and ileostomy for patients with ulcerative colitis, Gardner syndrome, and familial polyposis. To our knowledge, a careful radiographic analysis of the ileum, ileal pouch, and ileoanal anastomosis after ileoanal pull-through has not been reported. Thirty-two patients with ulcerative colitis, Gardner syndrome, and familial polyposis underwent colectomy, mucosal proctectomy, and endorectal ileoanal pull-through of a 15-cm ileal "J" pouch and loop ileostomy. Twenty-five (78%) of 32 of all the pouches radiographically demonstrated spiral folds extending from the middle of the pouch to the pectinate line. Other radiographic features included a mesenteric mass effect, pseudopolyps, and a central lucency that indicated intrapouch sutures. Radiographs provide useful information in the postoperative management of the ileal pull-through. 相似文献
37.
Marsh JC; Will AJ; Hows JM; Sartori P; Darbyshire PJ; Williamson PJ; Oscier DG; Dexter TM; Testa NG 《Blood》1992,79(12):3138-3144
We have used the long-term bone marrow culture (LTBMC) system to analyze hematopoiesis in three patients with dyskeratosis congenita (DC), two of whom had aplastic anemia, and the third had a normal blood count (apart from mild macrocytosis) and normal BM cellularity. Hematopoiesis was severely defective in all three patients, as measured by a low incidence of colony-forming cells and a low level of hematopoiesis in LTBMC. The function of the marrow stroma was normal in its ability to support the growth of hematopoietic progenitors from normal marrows seeded onto them in all three cases, but the generation of hematopoietic progenitors from patients marrow cells inoculated onto normal stromas was reduced, thus suggesting the defect to be of stem cell origin. The parents and unaffected brother of one of the families have also been studied in LTBMC and all showed normal hematopoietic and stromal cell function. From this study we speculate that there are some similarities between DC and the defect in the W/Wv mouse. 相似文献
38.
In clonogenic assays of hematopoietic progenitors, high concentrations (4 U/mL) of erythropoietin (epo) reduced the formation of granulocyte- macrophage (GM) colonies and diminished the number of granulocytes formed per culture plate. Fetal progenitors were more sensitive to these effects of epo than were progenitors from adults, displaying these reductions at greater than or equal to 1 U epo/mL. The mechanism was investigated by growing fetal progenitors stimulated by recombinant GM-CSF, in the absence of epo, and when eight-cell clones first appeared, mapping their location, then adding epo, and assessing its effect on the subsequent differentiation of the clones. In the absence of epo, the clones developed exclusively into GM colonies. However, if developing clones were presented with epo, 85% matured into GM colonies, but 15% became multilineage or normoblast colonies. In addition, developing clones that were presented with epo produced colonies that contained fewer neutrophils. These effects of epo on neutrophil generation were observed with each of three varieties of recombinant epo, and also with purified human epo, but were not observed using epo that had been neutralized with rabbit anti-epo antiserum. 相似文献
39.
Irene Paganini Vivian Y Chang Gabriele L Capone Jeremie Vitte Matteo Benelli Lorenzo Barbetti Roberta Sestini Eva Trevisson Theo JM Hulsebos Marco Giovannini Stanley F Nelson Laura Papi 《European journal of human genetics : EJHG》2015,23(7):963-968
Schwannomatosis is characterized by the development of multiple non-vestibular, non-intradermal schwannomas. Constitutional inactivating variants in two genes, SMARCB1 and, very recently, LZTR1, have been reported. We performed exome sequencing of 13 schwannomatosis patients from 11 families without SMARCB1 deleterious variants. We identified four individuals with heterozygous loss-of-function variants in LZTR1. Sequencing of the germline of 60 additional patients identified 18 additional heterozygous variants in LZTR1. We identified LZTR1 variants in 43% and 30% of familial (three of the seven families) and sporadic patients, respectively. In addition, we tested LZTR1 protein immunostaining in 22 tumors from nine unrelated patients with and without LZTR1 deleterious variants. Tumors from individuals with LZTR1 variants lost the protein expression in at least a subset of tumor cells, consistent with a tumor suppressor mechanism. In conclusion, our study demonstrates that molecular analysis of LZTR1 may contribute to the molecular characterization of schwannomatosis patients, in addition to NF2 mutational analysis and the detection of chromosome 22 losses in tumor tissue. It will be especially useful in differentiating schwannomatosis from mosaic Neurofibromatosis type 2 (NF2). However, the role of LZTR1 in the pathogenesis of schwannomatosis needs further elucidation. 相似文献
40.
Suppression of apoptosis in hematopoietic factor-dependent progenitor cell lines by expression of the FAC gene 总被引:2,自引:5,他引:2
Fanconi anemia (FA) is a genetically heterogeneous, inherited blood disorder characterized by bone marrow failure, congenital malformations, and a predisposition to leukemias. Because FA cells are hypersensitive to DNA cross-linking agents and have chromosomal instability, FA has been viewed as a disorder of DNA repair. However, the exact cellular defect in FA cells has not been identified. Sequence analysis of the gene defective in group C patients (FAC) has shown no significant homologies to other known genes. The FAC protein has been localized to the cytoplasm, indicating that FAC may either play an indirect role in DNA repair or is involved in a different cellular pathway. Recent evidence has indicated that FA cells may be predisposed to apoptosis, especially after treatment with DNA cross-linking agents. The demonstration that genes can suppress apoptosis has been accomplished by overexpression of such genes in growth factor-dependent cell lines that die by apoptosis after factor withdrawal. Using retroviral-mediated gene transfer, we present evidence that expression of FAC in the hematopoietic factor-dependent progenitor cell lines 32D and MO7e can suppress apoptosis induced by growth factor withdrawal. Flow cytometry and morphologic analysis of propidium iodide stained cells showed significantly lower levels of apoptosis in FAC-retroviral transduced cells after growth factor deprivation. Expression of FAC in both cell lines promoted increased viability rather than proliferation, which is consistent with other apoptosis-inhibiting genes such as Bcl- 2. These findings imply that FAC may act as a mediator of an apoptotic pathway initiated by growth factor withdrawal. Furthermore, the congenital malformations and hematologic abnormalities characterizing FA may be related to an increased predisposition of FA progenitor cells to undergo apoptosis, particularly in the absence of extracellular signals. 相似文献