全文获取类型
收费全文 | 29790篇 |
免费 | 2247篇 |
国内免费 | 288篇 |
专业分类
耳鼻咽喉 | 583篇 |
儿科学 | 385篇 |
妇产科学 | 428篇 |
基础医学 | 4912篇 |
口腔科学 | 862篇 |
临床医学 | 2742篇 |
内科学 | 5793篇 |
皮肤病学 | 1105篇 |
神经病学 | 2249篇 |
特种医学 | 1722篇 |
外科学 | 3693篇 |
综合类 | 151篇 |
现状与发展 | 3篇 |
一般理论 | 8篇 |
预防医学 | 1153篇 |
眼科学 | 524篇 |
药学 | 2907篇 |
中国医学 | 487篇 |
肿瘤学 | 2618篇 |
出版年
2023年 | 161篇 |
2022年 | 392篇 |
2021年 | 1165篇 |
2020年 | 633篇 |
2019年 | 880篇 |
2018年 | 1026篇 |
2017年 | 832篇 |
2016年 | 1196篇 |
2015年 | 1646篇 |
2014年 | 1744篇 |
2013年 | 2024篇 |
2012年 | 2930篇 |
2011年 | 2722篇 |
2010年 | 1666篇 |
2009年 | 1306篇 |
2008年 | 1790篇 |
2007年 | 1573篇 |
2006年 | 1338篇 |
2005年 | 1277篇 |
2004年 | 1018篇 |
2003年 | 888篇 |
2002年 | 734篇 |
2001年 | 422篇 |
2000年 | 402篇 |
1999年 | 327篇 |
1998年 | 151篇 |
1997年 | 130篇 |
1996年 | 88篇 |
1995年 | 73篇 |
1994年 | 75篇 |
1993年 | 68篇 |
1992年 | 117篇 |
1991年 | 135篇 |
1990年 | 112篇 |
1989年 | 102篇 |
1988年 | 91篇 |
1987年 | 77篇 |
1986年 | 81篇 |
1985年 | 65篇 |
1984年 | 43篇 |
1983年 | 38篇 |
1979年 | 57篇 |
1978年 | 37篇 |
1975年 | 52篇 |
1974年 | 31篇 |
1972年 | 40篇 |
1971年 | 49篇 |
1970年 | 34篇 |
1969年 | 28篇 |
1968年 | 32篇 |
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
91.
D. G. Kim C.-Y. Kim S. H. Paek D. S. Lee J.-K. Chung H.-W. Jung B.-K. Cho 《Acta neurochirurgica》1998,140(7):665-674
Summary
Background To determine its roles in the diagnosis and the systemic evaluation of metastatic brain tumours, whole-body positron emission
tomography (PET) using [18F]FDG was performed in 20 consecutive patients.
Methods
All patients were thought to be suffering or needing to be differentiated from metastatic brain tumours. Nine patients had
multiple brain lesions; six were older and showed a rim-enhancing lesion with surrounding oedema; seven had homogeneously
enhancing periventricular lesion(s) on computed tomography (CT) and/or magnetic resonance (MR) imaging, thought to be central
nervous system lymphomas. Two patients had skull mass(es) and two patients had a solid mass suspected to be, respectively,
a haemorrhagic metastasis and a metastatic malignant melanoma. All of them received whole-body [18F]FDG PET and conventional systemic work-up for metastasis in order to compare the results of the two methods.
Results
Metastatic brain tumours were diagnosed on whole-body [18F]FDG PET in eleven patients who had extracranial and intracranial hypermetabolic lesions. In nine of these, a conventional
work-up also detected primary lesions which on whole-body [18F]FDG PET were seen to be hypermetabolic foci. Systemic lymph node metastases were detected by whole-body [18F]FDG PET only in two patients and histological diagnosis was possible by biopsy of lymph nodes rather than of brain lesions.
In the remaining nine patients who had only intracranial hypermetabolic foci, histological diagnosis was made by craniotomy
or stereotactic biopsy. It was confirmed that seven of nine patients were suffering from a primary brain tumour and two from
metastatic carcinoma. None of the nine showed evidence of systemic cancer on conventional work-up. Histological diagnoses
of the primary brain tumours were four cases of primary central nervous system lymphoma and one each of multifocal glioblastoma,
Ewing's sarcoma, and cavernous angioma.
Patients felt no discomfort during the whole-body [18F]FDG PET procedure and there were no complications. The false negative rate in [18F]FDG PET and in conventional work-up was 15.4% and 30.7% respectively. There were no false positives on either [18F]FDG PET or conventional work-up.
Conclusion
It is suggested that whole-body [18F]FDG PET is a safe, reliable, and convenient method for the diagnosis and systemic evaluation of patients thought to be suffering
or needing to be differentiated from a metastatic brain tumour. 相似文献
92.
Zhao Canxi Wu Yan Lei Ying Ruan Heqiu Wolfgang Voelter Albrecht Jung Miriam Schick 《华中科技大学学报(医学英德文版)》1996,16(4):203-204
Zusammenfassung Die Wirkung des ?thylazetatextraktes von Chrysanthemum morifolium auf P. falciparum wurde in vitro untersucht. W?hrend sich
die Parasit?mie bei der Kontrollgruppe bis zu 10. 90 % entwickelte, wurde bei dem mit ?thylazetatextrakt in einer Konzentration
von 100 μg/ml Medium am 5. Tag der Kultur eine signifikante Hemmwirkung auf die Parasiten beobachtet. Die Parasit?mie blieb
bei 1. 00 %.
Diese Arbeit wurde durch die Stiftung von “National Nature Science Foundation of China” finanziert (No. 39260066) 相似文献
93.
Marion Jung EvaMaria Krämer Thomas Müller Horst Antonicek Jacqueline Trotter 《The European journal of neuroscience》1998,10(10):3246-3256
The immortalization of progenitor cells from embryonic murine hippocampus using oncogene‐carrying retroviral vectors is described. Use of a vector encoding the oncogene v‐myc results in lines of nestin‐positive progenitor cells. Limited differentiation ensues if the cells are cultured in the presence of dibutyryl cyclic adenosine monophosphate. In contrast, use of a vector in which the extracellular portion of the epidermal growth factor (EGF) receptor is fused to the neu tyrosine kinase generates lines of pluripotential nestin‐positive progenitor cells, which differentiate upon withdrawal of EGF into neurons and glia. Differentiated neurons expressing action potentials and neurotransmitter receptors make up a high proportion of the cells. These cell lines are useful tools to investigate the characteristics of differentiating neurons and glia, as well as to screen neuroactive drugs. This work has been reported in preliminary form as an abstract (1996 Society for Neuroscience Abstract, #606.20, p. 1537). 相似文献
94.
E G Jung 《Der Hautarzt; Zeitschrift für Dermatologie, Venerologie, und verwandte Gebiete》1989,40(12):761-762
"Schnyder's rule" states that multiple tumours of the skin are dominantly inherited, whereas solitary tumours of the same histological type are noninherited. This rule may be extended to cover segmental cases representing somatic mutations. 相似文献
95.
Overexpression of S100A4 is closely related to the aggressiveness of gastric cancer 总被引:25,自引:0,他引:25
Cho YG Nam SW Kim TY Kim YS Kim CJ Park JY Lee JH Kim HS Lee JW Park CH Song YH Lee SH Yoo NJ Lee JY Park WS 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2003,111(5):539-545
Elevated levels of the calcium-binding protein S100A4 cause metastasis of benign rat mammary tumor cells. To investigate whether S100A4 plays an important role in the invasion and metastasis of gastric cancers, we examined the gene mutations in the coding regions and expression patterns of the S100A4 in gastric adenocarcinoma in Korea. Moderate to strong expression of S100A4 was found in 53 (68.8%) of the 77 gastric adenocarcinomas, whilst normal gastric epithelium either failed to stain or showed weak staining. Interestingly, S100A4 expression was more frequently observed in gastric cancer patients with advanced gastric cancer (p=0.039), positive lymph node metastasis (p=0.001), and peritoneal dissemination (p=0.022). No gene mutations were found in the analyzed genomic area in 77 gastric adenocarcinomas and 15 gastric cancer cell lines. We found one single nucleotide polymorphism without an amino acid change, A99G, in two cases. These data suggest that the overexpression of S100A4 may be closely related to the aggressiveness of gastric cancer in Korea. 相似文献
96.
Chu PH Yeh HI Jung SM Chien LY Cheng NF Wu HH Chu JJ Hsueh C Lee YS 《Virchows Archiv : an international journal of pathology》2004,444(4):383-386
Cardiac hamartomas are very rare and are demarcated masses of enlarged, hypertrophied, mature myocytes and collagen tissue. Cardiac hamartomas are generally circumscribed in the right ventricle or atrium, but not reported in the crista terminalis (CRT). The CRT is crucial in electrophysiology, is related to arrhythmogenesis, and is targeted by radiofrequency catheter procedures. Previous works only described the benign natures of prominent CRT using non-invasive methods. This study describes an unusual cardiac hamartoma originating from the CRT and extending toward the tricuspid valve. Microscopically, this hamartoma comprised dense collagen and adipose tissue, mixed with hypertrophy, but with disarrayed cardiomyocytes. An irregular gap junction, connexin43, was demonstrated in this cardiac hamartoma. 相似文献
97.
Combined effects of inhaled nitric oxide and a recruitment maneuver in patients with acute respiratory distress syndrome 总被引:1,自引:0,他引:1
Nitric oxide (NO) inhalation therapy has been employed in the management of acute respiratory distress syndrome (ARDS), in order to improve oxygenation. Several factors have been implicated as being responsible for the action of inhaled NO. Alveolar recruitment methods, such as prone positioning and a sufficient positive end expiratory pressure (PEEP), have been identified as having a positive impact on the NO response. A Recruitment maneuver (RM) was introduced for the treatment of ARDS, along with a lung protective strategy. Here, we hypothesized that a RM may further augment the oxygenation of patients treated with NO inhalation. Therefore, the effects of the inhalation of NO, either in combination with a RM, or separately, were evaluated on patients with ARDS for their enhancing action. 23 patients with ARDS were enrolled, and divided into three groups. The patients in group 1 (n=11) were treated with 5 ppm NO via inhalation, followed by a RM, applying a sustained inflation pressure of 30 - 35 cmH2O for 30 seconds. Group 2 (n=6) received a RM alone, while group 3 (n=3) was treated with NO inhalation alone. The oxygenation and hemodynamic parameters were obtained prior to, and 2, 12, and 24 h after, the respective treatment procedures. For group 1, the PaO2/FiO2 increased from its initial value of 171.8 +/- 67.8 to 203.2 +/- 90.0 2 h after NO inhalation. Further improvement was noted with the continual application of the RM reaching, 215.5 +/- 74.6 (p=0.05) and 254.2 +/- 109.5 (p < 0.05), after 12 and 24 h, respectively. Initially 7 of the subjects did not respond to NO inhalation, but 3 of these non-responders changed into responders 12 h after the RM. The changes in the PaO2/FiO2 from baseline at each time period were greater in group 1 than in the other groups, but with no statistical significance. The hemodynamics of the patients was not significantly altered during the entire study period. We conclude that the combined application of NO inhalation and a RM could be beneficial and safe for patients with ARDS, showing an enhancing effect in improvement of oxygenation. 相似文献
98.
To test the hypothesis that complement-mediated cell lysis and cell-mediated cytotoxicity operate by analogous mechanisms, cell membranes from two antibody-dependent cytotoxicity systems were examined by electron microscopy after negative staining. Ring-shaped membrane lesions generally similar to, but larger than, those previously described for complement lysis were observed. These findings are in agreement with recent measurements of larger functional pores for ADCC than complement. 相似文献
99.
Integrin expression and osteopontin regulation in human fetal osteoblastic cells mediated by substratum surface characteristics 总被引:2,自引:0,他引:2
Integrin-mediated adhesion of anchorage-dependent cells to scaffolds is a critical component of tissue engineering. We investigated integrin expression by the human fetal osteoblastic cell line, hFOB 1.19 (hFOB), as a function of substratum surface wettability. The influence of surface wettability on bone cell phenotype was also examined. Plasma-treated quartz (PTQ) and glass (PTG) (hydrophilic, contact angles of 0 degrees), octadecyltrichlorosilane-treated quartz (STQ) and glass (STG) (hydrophobic, contact angles above about 100 degrees), and tissue culture polystyrene were used for cell culture. hFOB cells cultured on hydrophilic substrata displayed well-developed actin stress fibers relative to cells on hydrophobic substrata. Western blot analysis revealed that hFOB cells cultured on hydrophobic substrata (STQ or STG) express lower levels of alphav and beta3 integrin subunits than do cells on hydrophilic substrata (PTQ or PTG). This effect was more pronounced in cells on STQ than on STG. These variations in integrin expression were lessened by extended culture time. Double- labeled integrin/actin immunofluorescence confirmed Western blot results, that is, cells cultured on PTQ displayed distinct, large plaques of alphav and beta3 subunits and integrin alphavbeta3, as well as their colocalization with actin stress fiber ends, whereas cells on STQ did not display integrin plaques after 24 h and displayed only minimal plaque formation after 3 days. Vinculin, a focal adhesion protein that mediates binding between the integrin and actin cytoskeleton, appeared in Western blots to mimic the variations of alphav and beta3 expression with respect to surface wettability. Interestingly, real-time RT-PCR analysis showed that hFOB cultured on hydrophobic substrata, which have downregulated alphav and beta3 integrin subunits, displayed greater steady state mRNA levels of osteopontin, an extracellular matrix (ECM) protein containing the Arg-Gly-Asp (RGD) integrin recognition sequence, than did cells cultured on hydrophilic substrata. Our results imply that substratum surface wettability regulates integrin-mediated bone cell adhesion and further influences the expression of bone cell-ECM complexes. 相似文献
100.
Yu-Sheng Chang Pao-Hsien Chu Shih-Ming Jung Kun-Eng Lim Jaw-Ji Chu Chuen Hsueh Ying-Shiung Lee 《Cardiovascular pathology》2005,14(2):104-106
Cardiac papillary fibroelastoma (CPF) is the second most common benign neoplasm of the heart. This study describes the case of an 81-year-old man who was admitted to the hospital for severe vertigo and in whom a tumor at the right ventricular outflow tract (RVOT) was identified incidentally during echocardiography. The CPF was excised smoothly following the confirmation of its position by computed tomography. The comprehensive pathologic findings of CPF were reviewed. Detailed immunohistochemical analyses of CD34 and factor VIII-related antigen were performed on the covering endocardial cells. The unique chondroid metaplasia of fibrous tissue in this CPF has never been reported. This work is the first to present an unusual CPF at the RVOT with reactive process of fibrous connective tissue. 相似文献