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   1079篇
  免费   73篇
  国内免费   3篇
耳鼻咽喉   6篇
儿科学   16篇
妇产科学   16篇
基础医学   229篇
口腔科学   4篇
临床医学   76篇
内科学   255篇
皮肤病学   21篇
神经病学   111篇
特种医学   20篇
外科学   65篇
综合类   8篇
预防医学   58篇
眼科学   19篇
药学   152篇
中国医学   6篇
肿瘤学   93篇
  2024年   1篇
  2023年   5篇
  2022年   21篇
  2021年   42篇
  2020年   28篇
  2019年   33篇
  2018年   39篇
  2017年   33篇
  2016年   55篇
  2015年   39篇
  2014年   52篇
  2013年   62篇
  2012年   106篇
  2011年   114篇
  2010年   56篇
  2009年   55篇
  2008年   72篇
  2007年   65篇
  2006年   48篇
  2005年   60篇
  2004年   55篇
  2003年   41篇
  2002年   31篇
  2001年   5篇
  2000年   2篇
  1999年   4篇
  1998年   6篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
  1994年   3篇
  1992年   7篇
  1991年   1篇
  1990年   1篇
  1988年   1篇
  1986年   2篇
  1985年   1篇
  1984年   1篇
  1981年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
排序方式: 共有1155条查询结果,搜索用时 687 毫秒
71.
72.
A prognostic impact of WHO classification of myelodysplastic syndrome (MDS) was studied in a group of 103 primary MDS patients with refractory anemia (RA) according to French-American-British (FAB) classification. Median survival of 37 patients with RA according to WHO criteria of 85.2 months was significantly different from that in both 37 patients with refractory cytopenia with multilineage dysplasia (RCMD) (47.0 months, P=0.002) and 29 patients with 5q- abnormality diagnosed by routine chromosome banding (36.2 months, P=0.0002). A more detailed karyotype analysis with fluorescent in situ hybridization (FISH) techniques confirmed 5q deletion as a sole cytogenetic abnormality in only 12 out of 29 patients, in 4 patients 5q- was associated with complex abnormalities involving 5q region, 13 patients had 5q deletion combined with further karyotype abberations outside 5q. No difference in median survival and estimated 3 years survival was observed between RA patients, patients with 5q- syndrome according to WHO morphology criteria and patients with 5q- as a single abnormality confirmed by FISH in contrast to patients with either additional 5q abberations or further karyotype changes not involving 5q. The same difference was also observed in time to 25% of patients evolving to acute myeloid leukemia (AML). Our study confirmed usefulness of separation of RCMD from RA. RCMD represents a poor prognostic subgroup of MDS clearly distinct from pure RA mainly due to short survival connected with progressive bone marrow failure and increased risk of leukemic transformation. We also suggest to define 5q- syndrome as primary MDS of FAB type RA with 5q deletion as a sole cytogenetic abnormality confirmed by FISH analysis. This definition enabled us to discriminate 5q- patients with favorable prognosis similar as in RA from those with poor outcome associated with 5q- combined with complex abnormalities involving either 5q or regions outside 5q.  相似文献   
73.
DNA mismatch repair (MMR) defects bring about a strong mutator phenotype and microsatellite instability (MSI). In an attempt to exploit MSI in cancer therapy, we constructed expression vectors carrying a thymidine kinase/blasticidin deaminase fusion gene downstream from a (C)(12) or an (A)(26) microsatellite and stably transfected these constructs into human cells in which the MMR status could be regulated by doxycycline. We now show that ganciclovir-resistant clones arising through frameshifts in the (C)(12) microsatellite were 20 times more frequent in cells in which MMR was inactivated. This difference may be exploited in gene therapy of tumors with MSI, which represent a substantial proportion of cancers of many different tissues.  相似文献   
74.
OBJECTIVE: More than 90% of congenital hearing loss cases are of cochlear origin. There are two methods for newborn hearing screening: the transient otoacoustic emission (TEOAE) or (ABR) screening. When TEOAE is used for hearing screening patients, newborn with a neural hearing loss are not discovered. MATERIALS: In the present study TEOAEs were obtained from 3,048 newborns from both ears in patients with and without risk factors for hearing loss in the history. All newborns who did not pass TEOAE in the 2nd screening (uni or bilaterally) underwent additional audiologic tests. RESULTS: In the first screening 150 (4.5%) of the newborns newborn did not pass the screening and 30 (0.98%) did not pass in the second screening. In nine newborns with unilateral absent TEOAE and in two newborns a deafness was confirmed, with one side cochlear and on the other side retrocochlear. Both patients received cochlear implants before the 2nd year of age. In 21 newborns with absent TEOAE bilaterally, five had moderate sensorineural hearing loss bilaterally and in nine patients profound hearing loss (90-100 dB) or deafness was confirmed. Of 3,048 newborns there were 1,355 with a risk of hearing loss and in 12 (0.88%) newborns bilateral hearing loss or deafness was confirmed; of the 1663 newborns without risk of hearing loss in the history, in four (0.24%) newborn deafness or bilateral sensorineural hearing loss in the range of 45-65 dB were confirmed. CONCLUSION: When the newborn has an absent TEOAE uni or bilaterally, we need to inform the parents and to recommend additional screening and other audiologic tests to confirm or exclude hearing loss.  相似文献   
75.
76.
Francisella tularensis is a facultative intracellular, gram-negative bacterium that induces apoptosis in macrophages and B cells. Here we show apoptotic pathways that are activated in the Ramos human B cell line in the course of F. tularensis infection. Live bacteria F. tularensis FSC200 activate caspases 8, 9 and 3, as well as Bid; release cytochrome c and apoptosis-inducing factor from mitochondria; and induce depolarization of mitochondrial membrane potential in the Ramos cell line, thus leading these cells to apoptosis. Unlike live bacteria, killed F. tularensis FSC200 bacteria activated only caspase 3, and did not cause apoptosis of Ramos cells as measured by annexin V. Killed bacteria also caused accumulation of anti-apoptotic protein BclxL in mitochondrial membranes. Thus, live F. tularensis activates both caspase pathways (receptor-mediated and intrinsic) as well as caspase-independent mitochondrial death.  相似文献   
77.
The visualization of the human body has frequently been groundbreaking in medicine. In the last few years, the use of ultrasound (US) imaging has become a well-established procedure for botulinum toxin therapy in people with cervical dystonia (CD). It is now undisputed among experts that some of the most relevant muscles in this indication can be safely injected under visual US guidance. This review will explore the method from basic technical considerations, current evidence to conceptual developments of the phenomenology of cervical dystonia. We will review the implications of introducing US to our understanding of muscle function and anatomy of common cervical dystonic patterns. We suggest a flow chart for the use of US to achieve a personalized treatment of people with CD. Thus, we hope to contribute a resource that is useful in clinical practice and that stimulates the ongoing development of this valuable technique.  相似文献   
78.
Graft‐versus‐host disease (GVHD) prophylaxis of short duration (6 months) with low‐dose cyclosporine A (CsA) starting at 1 mg/kg per day i.v. and four doses of methotrexate (MTX) were given to 171 consecutive leukaemic recipients of HLA‐identical sibling transplants. In contrast, apart from MTX, retrospective controls received high‐dose CsA, starting at 5–7.5 mg/kg per day i.v. and discontinued 1 yr post‐transplant. In the low‐dose CsA group, the probability of acute GVHD grades I–II (70% vs. 53%, P < 0.01), and chronic GVHD were increased (58% vs. 25%, P < 0.01), whereas the incidences of acute GVHD grades III–IV (9% vs. 5%, P = 0.62), and non‐relapse mortality (20% vs. 22%, P = 0.58) were similar. Moreover, the probability of relapse was decreased (31% vs. 54%, P < 0.01), and both relapse‐free (56% vs. 38%, P = 0.04) and overall survival (61% vs. 40%, P = 0.04) were markedly improved using the low‐dose CsA regimen. In multivariate analyses, low‐dose CsA was strongly associated with chronic GVHD [relative hazard (RH) 2.56, P < 0.01], which decreased the risk of relapse (RH 0.46, P < 0.01) and improved the probability of survival (RH 1.84, P < 0.01). In conclusion, a low‐dose CsA regimen in leukaemic recipients of HLA‐identical sibling transplants increases the rate of chronic GVHD, which seems to attenuate the risk of relapse, thereby improving patient survival owing to enhanced graft‐versus‐leukaemia effect.  相似文献   
79.
Temporal bone reconstruction is a persisting problem following middle ear cholesteatoma surgery. Seeking to advance the clinical transfer of stem cell therapy we attempted the reconstruction of temporal bone using a composite bioartificial graft based on a hydroxyapatite bone scaffold combined with human bone marrow-derived mesenchymal stromal cells (hBM-MSCs). The aim of this study was to evaluate the effect of the combined biomaterial on the healing of postoperative temporal bone defects and the preservation of physiological hearing functions in a guinea pig model. The treatment’s effect could be observed at 1 and 2 months after implantation of the biomaterial, as opposed to the control group. The clinical evaluation of our results included animal survival, clinical signs of an inflammatory response, and exploration of the tympanic bulla. Osteogenesis, angiogenesis, and inflammation were evaluated by histopathological analyses, whereas hBM-MSCs survival was evaluated by immunofluorescence assays. Hearing capacity was evaluated by objective audiometric methods, i.e. auditory brainstem responses and otoacoustic emission. Our study shows that hBM-MSCs, in combination with hydroxyapatite scaffolds, improves the repair of bone defects providing a safe and effective alternative in their treatment following middle ear surgery due to cholesteatoma.  相似文献   
80.
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