全文获取类型
收费全文 | 9516篇 |
免费 | 592篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 48篇 |
儿科学 | 260篇 |
妇产科学 | 161篇 |
基础医学 | 1836篇 |
口腔科学 | 249篇 |
临床医学 | 775篇 |
内科学 | 1911篇 |
皮肤病学 | 295篇 |
神经病学 | 1206篇 |
特种医学 | 315篇 |
外科学 | 821篇 |
综合类 | 42篇 |
一般理论 | 6篇 |
预防医学 | 526篇 |
眼科学 | 143篇 |
药学 | 597篇 |
中国医学 | 19篇 |
肿瘤学 | 931篇 |
出版年
2024年 | 6篇 |
2023年 | 61篇 |
2022年 | 136篇 |
2021年 | 232篇 |
2020年 | 181篇 |
2019年 | 248篇 |
2018年 | 285篇 |
2017年 | 183篇 |
2016年 | 283篇 |
2015年 | 297篇 |
2014年 | 384篇 |
2013年 | 499篇 |
2012年 | 725篇 |
2011年 | 775篇 |
2010年 | 407篇 |
2009年 | 425篇 |
2008年 | 637篇 |
2007年 | 678篇 |
2006年 | 630篇 |
2005年 | 633篇 |
2004年 | 591篇 |
2003年 | 540篇 |
2002年 | 453篇 |
2001年 | 87篇 |
2000年 | 73篇 |
1999年 | 88篇 |
1998年 | 119篇 |
1997年 | 71篇 |
1996年 | 68篇 |
1995年 | 59篇 |
1994年 | 44篇 |
1993年 | 37篇 |
1992年 | 18篇 |
1991年 | 21篇 |
1990年 | 15篇 |
1989年 | 17篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 13篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1983年 | 10篇 |
1979年 | 9篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 7篇 |
1963年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Vanderzwalmen P Hiemer A Rubner P Bach M Neyer A Stecher A Uher P Zintz M Lejeune B Vanderzwalmen S Cassuto G Zech NH 《Reproductive biomedicine online》2008,17(5):617-627
Spermatozoa selection at high magnification before intracytoplasmic sperm injection seems to be positively associated with pregnancy rates after day 3 embryo transfers. The aim was to demonstrate an association between the presence of vacuoles in sperm nuclei and the competence of embryos to develop to day 5. Grading of spermatozoa at x 6000-x 12,500 magnification: grade I, no vacuoles; grade II, or=1 large vacuole; grade IV, large vacuoles with other abnormalities. The outcome of embryo development in a group of 25 patients after sibling oocyte injection with the four different grades of spermatozoa showed no significant difference in embryo quality up to day 3. However, the occurrence of blastocyst formation was 56.3 and 61.4% with grade I and II spermatozoa respectively, compared with 5.1% with grade III and 0% with grade IV respectively (P < 0.001). Spermatozoa selection at high magnification using Nomarski interference contrast is useful to identify more precisely the size and the number of nuclear vacuoles that greatly exert a negative effect on embryo development to the blastocyst stage. These observations confirm previous studies pointing to possible 'early and late paternal effects', both of which may have an impact on early embryonic development. 相似文献
63.
Michael R. van Gerven Eva Bozsaky Yvette A. H. Matser Julian Vosseberg Sabine TaschnerMandl Jan Koster Godelieve A. M. Tytgat Jan J. Molenaar Marlinde van den Boogaard 《Cancer science》2022,113(6):2167
Neuroblastoma is the most common extracranial solid tumor in children. The chromatin remodeler ATRX is frequently mutated in high‐risk patients with a poor prognosis. Although many studies have reported ATRX aberrations and the associated clinical characteristics in neuroblastoma, a comprehensive overview is currently lacking. In this study, we extensively characterize the mutational spectrum of ATRX aberrations in neuroblastoma tumors reported in previous studies and present an overview of patient and tumor characteristics. We collected the data of a total of 127 neuroblastoma patients and three cell lines with ATRX aberrations originating from 20 papers. We subdivide the ATRX aberrations into nonsense, missense, and multiexon deletions (MEDs) and show that 68% of them are MEDs. Of these MEDs, 75% are predicted to be in‐frame. Furthermore, we identify a missense mutational hotspot region in the helicase domain. We also confirm that all three ATRX mutation types are more often identified in patients diagnosed at an older age, but still approximately 40% of the patients are aged 5 years or younger at diagnosis. Surprisingly, we found that 11q deletions are enriched in neuroblastomas with ATRX deletions compared to a reference cohort, but not in neuroblastomas with ATRX point mutations. Taken together, our data emphasizes a distinct ATRX mutation spectrum in neuroblastoma, which should be considered when studying molecular phenotypes and therapeutic strategies. 相似文献
64.
Sabine Hummel Katharina Obermeier Katja Zier Sandra Krommes Michael Schemme Peter Karlinger 《Materials》2022,15(11)
Increasing demand for energy-efficient means of transport has steadily intensified the trend towards lightweight components. Thermoplastic glass fiber composites (organo sheets) play a major role in the production of functional automotive components. Organo sheets are cut, shaped and functionalized by injection molding to produce hybrid components, such as those used in car door modules. The cutting process produces a considerable amount of production waste, which has thus far been thermally recycled. This study develops a closed mechanical recycling process and analyzes the different steps of the process. The offcuts were shredded using two shredding methods and implemented directly in the injection-molding process. Using tensile tests and impact bending tests, the material properties of the recycled materials were compared with the virgin material. In addition, fiber length degradation via the injection-molding process and the influence of the waterjet-cutting process on the mechanical properties are investigated. Recycled offcuts are both comparable to new material in terms of mechanical properties and usability, and are also economically and ecologically advantageous. Recycling polypropylene waste with glass fiber reinforcement in a closed loop is an effective way to reduce industrial waste in a sustainable and economical production process. 相似文献
65.
Dominik N?rz Susanne Pfefferle Thomas Brehm Gefion Franke Ilka Grewe Birte Knobling Martin Aepfelbacher Samuel Huber Eva M. Klupp Sabine Jordan Marylyn M. Addo Julian Schulze zur Wiesch Stefan Schmiedel Marc Lütgehetmann Johannes K. Knobloch 《Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin》2022,27(26)
66.
Occult lung infarction may induce false interpretation of 18F-FDG PET in primary staging of pulmonary malignancies 总被引:3,自引:0,他引:3
Kamel EM McKee TA Calcagni ML Schmidt S Markl S Castaldo S Delaloye AB 《European journal of nuclear medicine and molecular imaging》2005,32(6):641-646
Purpose The aim of the present report is to describe abnormal 18F-fluorodeoxyglucose (FDG) accumulation patterns in the pleura and lung parenchyma in a group of lung cancer patients in whom lung infarction was present at the time of positron emission tomography (PET).Methods Between November 2002 and December 2003, a total of 145 patients (102 males, 43 females; age range 38–85 years) were subjected to whole-body FDG PET for initial staging (n=117) or restaging (n=11) of lung cancer or for evaluation of solitary pulmonary nodules (n=17). Of these patients, 24 displayed abnormal FDG accumulation in the lung parenchyma that was not consistent with the primary lesion under investigation (ipsilateral n=12, contralateral n=9 or bilateral n=3). Without correlative imaging, this additional FDG uptake would have been considered indeterminate in differential diagnosis.Results Of the 24 patients who were identified as having such lesions, six harboured secondary tumour nodules diagnosed as metastases, while in three the diagnosis of a synchronous second primary lung tumour was established. Additionally, nine patients were identified as having post-stenotic pneumonia and/or atelectasis (n=6) or granulomatous lung disease (n=3). In the remaining six (4% of all patients), a diagnosis of recent pulmonary embolism that topographically matched the additional FDG accumulation (SUVmax range 1.4–8.6, mean 3.9) was made. Four of these six patients were known to have pulmonary embolism, and hence false positive interpretation was avoided by correlating the PET findings with those of the pre-existing diagnostic work-up. The remaining two patients were harbouring small occult infarctions that mimicked satellite nodules in the lung periphery. Based on histopathological results, the abnormal FDG accumulation in these two patients was attributed to the inflammatory reaction and tissue repair associated with the pathological cascade of pulmonary embolism.Conclusion In patients with pulmonary malignancies, synchronous lung infarction may induce pathological FDG accumulation that can mimic active tumour manifestations. Identifying this potential pitfall may allow avoidance of false positive FDG PET interpretation. 相似文献
67.
Material differentiation by dual energy CT: initial experience 总被引:9,自引:0,他引:9
Johnson TR Krauss B Sedlmair M Grasruck M Bruder H Morhard D Fink C Weckbach S Lenhard M Schmidt B Flohr T Reiser MF Becker CR 《European radiology》2007,17(6):1510-1517
The aim of this study was to assess the feasibility of a differentiation of iodine from other materials and of different body
tissues using dual energy CT. Ten patients were scanned on a SOMATOM Definition Dual Source CT (DSCT; Siemens, Forchheim,
Germany) system in dual energy mode at tube voltages of 140 and 80 kVp and a ratio of 1:3 between tube currents. Weighted
CT Dose Index ranged between 7 and 8 mGy, remaining markedly below reference dose values for the respective body regions.
Image post-processing with three-material decomposition was applied to differentiate iodine or collagen from other tissue.
The results showed that a differentiation and depiction of contrast material distribution is possible in the brain, the lung,
the liver and the kidneys with or without the underlying tissue of the organ. In angiographies, bone structures can be removed
from the dataset to ease the evaluation of the vessels. The differentiation of collagen makes it possible to depict tendons
and ligaments. Dual energy CT offers a more specific tissue characterization in CT and can improve the assessment of vascular
disease. Further studies are required to draw conclusions on the diagnostic value of the individual applications. 相似文献
68.
Leonora W. de Boo Katarzyna J
wiak Heikki Joensuu Henrik Lindman Susanna Lauttia Mark Opdam Charlaine van Steenis Wim Brugman Roelof J. C. Kluin Philip C. Schouten Marleen Kok Petra M. Nederlof Michael Hauptmann Sabine C. Linn 《British journal of cancer》2022,126(10):1401
Background The addition of adjuvant capecitabine to standard chemotherapy of early-stage triple-negative breast cancer (TNBC) patients has improved survival in a few randomised trials and in meta-analyses. However, many patients did not benefit. We evaluated the BRCA1-like DNA copy number signature, indicative of homologous recombination deficiency, as a predictive biomarker for capecitabine benefit in the TNBC subgroup of the FinXX trial.Methods Early-stage TNBC patients were randomised between adjuvant capecitabine-containing (TX + CEX: capecitabine-docetaxel, followed by cyclophosphamide-epirubicin-capecitabine) and conventional chemotherapy (T + CEF: docetaxel, followed by cyclophosphamide-epirubicin-fluorouracil). Tumour BRCA1-like status was determined on low-coverage, whole genome next-generation sequencing data using an established DNA comparative genomic hybridisation algorithm.Results For 129/202 (63.9%) patients the BRCA1-like status could be determined, mostly due to lack of tissue. During a median follow-up of 10.7 years, 35 recurrences and 32 deaths occurred. Addition of capecitabine appears to improve recurrence-free survival more among 61 (47.3%) patients with non-BRCA1-like tumours (HR 0.23, 95% CI 0.08–0.70) compared to 68 (52.7%) patients with BRCA1-like tumours (HR 0.66, 95% CI 0.24–1.81) (P-interaction = 0.17).Conclusion Based on our data, patients with non-BRCA1-like TNBC appear to benefit from the addition of capecitabine to adjuvant chemotherapy. Patients with BRCA1-like TNBC may also benefit. Additional research is needed to define the subgroup within BRCA1-like TNBC patients who may not benefit from adjuvant capecitabine.Subject terms: Breast cancer, Translational research, Predictive markers, Breast cancer 相似文献
69.
Vanessa Rouzier Karine Severe Marc Antoine Jean Juste Mireille Peck Christian Perodin Patrice Severe Marie Marcelle Deschamps Rose Irene Verdier Sabine Prince Jeannot Francois Jean Ronald Cadet Florence D. Guillaume Peter F. Wright Jean W. Pape 《The American journal of tropical medicine and hygiene》2013,89(4):671-681
Successful and sustained efforts have been made to curtail the major cholera epidemic that occurred in Haiti in 2010 with the promotion of hygiene and sanitation measures, training of health personnel and establishment of treatment centers nationwide. Oral cholera vaccine (OCV) was introduced by the Haitian Ministry of Health as a pilot project in urban and rural areas. This paper reports the successful OCV pilot project led by GHESKIO Centers in the urban slums of Port-au-Prince where 52,357 persons received dose 1 and 90.8% received dose 2; estimated coverage of the at-risk community was 75%. This pilot study demonstrated the effort, community mobilization, and organizational capacity necessary to achieve these results in a challenging setting. The OCV intervention paved the way for the recent launching of a national cholera vaccination program integrated in a long-term ambitious and comprehensive plan to address Haiti''s critical need in water security and sanitation. 相似文献
70.
Marie-Irène Malewiak Sabine Griglio Xavier Le Liepvre 《Metabolism: clinical and experimental》1985,34(7):604-611
The relationship between lipogenesis and ketogenesis and the concentration of malonyl coenzyme A (CoA) was investigated in hepatocytes from adult obese Zucker rats and their lean littermates fed either a control low-fat diet or a high-fat diet (30% lard in weight). With the control diet, lipogenesis—although strongly inhibited in the presence of either 1 mmol/L oleate, 10?6 mol/L glucagon or 0.1 mmol/L TOFA (a hypolipidemic drug)—remained about fifteen-fold higher in the obese rats than in the lean rats. In contrast, ketogenesis under some conditions (oleate + TOFA) was not significantly lower (30%) as compared with the lean rats. After adaptation to the high-fat diet, lipogenesis was depressed fourfold in the lean rats and ninefold in the obese ones; however its magnitude remained significantly higher in the latter, namely at a value close to that measured in control-fed lean rats. Ketogenesis was comparable in lean and obese rats and much higher in the presence of 1 mmol/L oleate than of 0.3 mmol/L oleate, whereas lipogenesis did not vary with increasing oleate concentration in the medium. Acetyl-CoA carboxylase activity measured in liver homogenates was higher in the obese group, but was stepwise inhibited by increasing concentrations of oleyl-CoA regardless of the diet for both lean and obese rats, thus showing no abnormality of in vitro responsiveness to this inhibitor. With the control diet, hepatocyte malonyl-CoA levels were significantly higher in the obese rats, both in the basal state and after inhibition of lipogenesis by oleate and TOFA. However, after the high-fat diet, there was no longer a significant difference between the genotypes. These results show that in the obese Zucker rats, ketogenesis is dependent on hepatocyte malonyl-CoA content in the sense that their ketogenic capacity becomes “normalized” when malonyl-CoA is decreased to the levels found in the lean littermates, as it is the case after fat-feeding. This normalization of malonyl-CoA levels in spite of higher lipogenesis in the obese rats may result from the activities of enzymes of its formation and utilization. 相似文献