全文获取类型
收费全文 | 23598篇 |
免费 | 1301篇 |
国内免费 | 257篇 |
专业分类
耳鼻咽喉 | 472篇 |
儿科学 | 301篇 |
妇产科学 | 266篇 |
基础医学 | 4293篇 |
口腔科学 | 555篇 |
临床医学 | 1877篇 |
内科学 | 4483篇 |
皮肤病学 | 886篇 |
神经病学 | 1799篇 |
特种医学 | 1317篇 |
外科学 | 2925篇 |
综合类 | 133篇 |
现状与发展 | 1篇 |
一般理论 | 5篇 |
预防医学 | 1064篇 |
眼科学 | 448篇 |
药学 | 2078篇 |
中国医学 | 284篇 |
肿瘤学 | 1969篇 |
出版年
2023年 | 148篇 |
2022年 | 509篇 |
2021年 | 810篇 |
2020年 | 402篇 |
2019年 | 567篇 |
2018年 | 641篇 |
2017年 | 527篇 |
2016年 | 729篇 |
2015年 | 1080篇 |
2014年 | 1289篇 |
2013年 | 1424篇 |
2012年 | 2155篇 |
2011年 | 2040篇 |
2010年 | 1154篇 |
2009年 | 1036篇 |
2008年 | 1445篇 |
2007年 | 1323篇 |
2006年 | 1138篇 |
2005年 | 1003篇 |
2004年 | 862篇 |
2003年 | 751篇 |
2002年 | 644篇 |
2001年 | 568篇 |
2000年 | 469篇 |
1999年 | 391篇 |
1998年 | 153篇 |
1997年 | 113篇 |
1996年 | 83篇 |
1995年 | 93篇 |
1994年 | 60篇 |
1993年 | 45篇 |
1992年 | 142篇 |
1991年 | 148篇 |
1990年 | 108篇 |
1989年 | 122篇 |
1988年 | 101篇 |
1987年 | 108篇 |
1986年 | 94篇 |
1985年 | 86篇 |
1984年 | 63篇 |
1983年 | 58篇 |
1982年 | 38篇 |
1981年 | 38篇 |
1980年 | 30篇 |
1979年 | 48篇 |
1978年 | 49篇 |
1977年 | 42篇 |
1976年 | 32篇 |
1974年 | 30篇 |
1973年 | 34篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
Malignant granular cell tumor at the retrotracheal space 总被引:3,自引:0,他引:3
We report a case of an extremely rare neoplasm, malignant granular cell tumor (MGCT). The patient was a 21-year-old woman, who was 5 months pregnant. The tumor occurred in the retrotracheal space, extending from the level of the larynx to the thoracic inlet. In addition, there were multiple, variable-sized tumor nodules within both lung fields on chest CT scan. Histologically, tissue biopsied from the periphery of the tumor consisted of solid sheets of large ovoid cells with ample, eosinophilic cytoplasm, eccentric nuclei, and prominent nucleoli. Each cell showed slight atypism of the nuclei. There was a focal necrosis at the periphery of the lesion. These cells stained strongly for S-100 protein, neuron-specific enolase (NSE) and CD68. On electron microscopy, the tumor cells contained autophagic vacuoles. The patient refused further treatment and died 7 months later. The exact cause of death was not known. Until now, the diagnosis of MGCTs has been made only when metastasis and an aggressive clinical course are identified, although some observers advocate that some histologic features such as nuclear pleomorphism, necrosis, and the presence of any mitotic activity are indicative of malignancy. These histologic findings are not easily detectable in every case of MGCT, as in our case. So the diagnosis of a MGCT should be considered in cases with aggressive clinical findings and some histologic features, such as necrosis, nuclear atypism, and mitotic activities, which could suggest the malignant behavior of this neoplasm. 相似文献
92.
Coronary microvascular abnormalities in the hypertensive-diabetic rat. A primary cause of cardiomyopathy? 总被引:2,自引:1,他引:2 下载免费PDF全文
S M Factor T Minase S Cho F Fein J M Capasso E H Sonnenblick 《The American journal of pathology》1984,116(1):9-20
The authors have continued their investigation of the hypertensive-diabetic (HD) rat by evaluating changes in the myocardial microvasculature in this model. Perfusion of HD animals in vivo with a silicone rubber solution revealed numerous areas of microvascular tortuosity, focal constrictions, and microaneurysm formation. These alterations were present to a lesser extent in normoglycemic hypertensive (H) rats, and were distinctly rare in normotensive diabetic rats and unaffected control animals. Quantitation of these vascular lesions revealed highly significant differences between HD animals and the other three groups, with hypertensive rats intermediate between HD rats and diabetic control rats. Areas of pronounced arteriolar constriction were also identified in the HD and H animals with the use of serial sections of Epon-embedded myocardium. It is believed that these lesions represent dynamic changes in the microcirculation, which may cause segmental reperfusion injury to the myocardium, leading to focal replacement fibrosis. Interstitial scarring may result from increased leakiness of small vessels exacerbated by the combined disease. The authors propose that the additive effects of hypertension and diabetes mellitus on the myocardial microcirculation may be a primary cause of cardiomyopathy in this model of human disease. 相似文献
93.
Chung JH Yang JH Song MJ Cho JY Lee YH Park SY Moon MJ Lim HJ Choi JS Kim JO Shin JS Ahn HK Han JY Kim MY Choi KH Ryu HM 《Journal of Korean medical science》2004,19(1):32-36
The aim of present study was to establish normative data for the distribution of nuchal translucency (NT) thickness in normal Korean fetuses. The data were collected from pregnant women with singleton pregnancies in whom fetal ultrasound was performed and the fetal NT thickness was measured between 11 and 14 weeks of gestation. Among them, a total of 2,577 fetuses with a known normal outcome were included in this study. The distribution of multiple of median (MoM) values of the NT thickness with crown-rump length (CRL) in 10-mm intervals and the 95th percentile of MoM were calculated with the linear regression method. The present study showed that NT measurements increase with increasing CRL and a false positive rate increases with increasing gestational age. Therefore, a fixed cut-off point through the first trimester was not appropriate and each NT measurement should be examined according to the gestational age. The present study offers normative data of the fetal NT thickness in a Korean population, which can be used as reference for screening chromosomal aberrations or other congenital abnormalities in the first trimester. 相似文献
94.
Lectin affinity electrophoresis in a yolk sac tumour in the vagina with yolk sac tumour-type glycoform of alpha fetoprotein. 下载免费PDF全文
R Yamamoto K Taketa Y Ebina Y Cho H Hareyama N Sakuragi S Makinoda K Kobayashi S Nishi S Fujimoto 《Journal of clinical pathology》1997,50(10):856-858
AIMS: To investigate a potential diagnostic use of alpha fetoprotein (alpha FP) isoform analysis by lectin affinity electrophoresis to distinguish between endodermal sinus tumours arising in the vagina in infants from those at other sites. METHODS: alpha FP in the serum of a patient with a vaginal endodermal sinus tumour was analysed for its isoforms by lectin affinity electrophoresis. The isoforms were compared with that of cord serum, sera of hepatoid adenocarcinoma of the uterus, and endodermal sinus tumour of the ovary. RESULTS: The isoforms of alpha FP obtained by lectin affinity electrophoresis in the serum of the patient with vaginal endodermal sinus tumour differed from the isoforms of alpha FP in the cord serum of normal neonates, and sera of patients with hepatoid adenocarcinoma of the uterus or endodermal sinus tumour of the ovary. CONCLUSIONS: Endodermal sinus tumour arising in the vagina could be distinguished from that in the ovary by the lectin affinity electrophoresis, and a potential diagnostic use of alpha FP isoform analysis by the lectin affinity electrophoresis for the detection of the endodermal sinus tumour in infants was demonstrated. 相似文献
95.
Production of monoclonal antibody to a phenolic glycolipid of Mycobacterium tuberculosis and its use in detection of the antigen in clinical isolates. 下载免费PDF全文
S N Cho J S Shin M Daffe Y Chong S K Kim J D Kim 《Journal of clinical microbiology》1992,30(12):3065-3069
A monoclonal antibody (MAbIII604) specific to phenolic glycolipid Tb (PGL-Tb), a Mycobacterium tuberculosis-specific antigen, was produced and used in the detection of the antigen. MAbIII604 reacted with the PGL-Tb antigen but not with other phenolic glycolipids from Mycobacterium leprae, M. bovis, and M. kansasii, thus indicating the specificity of the monoclonal antibody to PGL-Tb. A dot enzyme-linked immunosorbent assay with MAbIII604 was employed to detect the PGL-Tb antigen in lipids purified from M. tuberculosis clinical isolates. Of 50 isolates, 32 (64.0%) showed clear evidence of the PGL-Tb antigen by the dot enzyme-linked immunosorbent assay, but there were marked variations in the intensities and sizes of spots. This suggests differences in PGL-Tb antigen production among M. tuberculosis strains even when they are grown in the same culture media and conditions. This was most evident from the fact that in only eight (16.0%) of the isolates examined was the PGL-Tb antigen detectable by thin-layer chromatography, which is much less sensitive for the detection of glycolipid antigens. This study shows that monoclonal antibodies specific to PGL-Tb are useful in detecting the antigen in lipid extracts and that there is a marked variation in the PGL-Tb production among M. tuberculosis clinical isolates. 相似文献
96.
Sang-Hyun Cho Dong Gyu Kim Dae-Shik Kim Yun-Hee Kim Chu-Hee Lee Sung Ho Jang 《Neuroscience letters》2007
Diffusion tensor tractography (DTT) is useful for exploring the state of the corticospinal tract (CST). An accurate estimation of the integrity of the CST in the early stage of a cerebral infarct would enable a determination of motor recovery. DTT was performed to classify CST integrity following a corona radiata infarct to evaluate if the procedure could characterize the motor outcome of the affected hand. Fifty-five patients with completely paralyzed hands due to a corona radiata infarct were recruited for the study, and DTT images were obtained within 7–30 days after a stroke. The DTI findings for the patients were classified into four groups. In type A, the CST was preserved around the infarct; in type B, the CST originated from a cortex other than the primary motor cortex; in type C, the CST was interrupted at the infarct; in type D, the CST failed to reach the infarct due to degeneration. Six months after a stroke, the motor function of the affected hand was evaluated with the motricity index (MI) for the hand, the Medical Research Council score (MRC) for finger extensors and the modified Brunnstrom classification (MBC). These indices were significantly influenced by the DTT type (p < 0.05). The highest MI, MRC and MBC were seen in the DTT type A patients; the lowest MI, MRC and MBC were seen in the DTT type D patients (p < 0.05). The integrity of the corticospinal tract determined by DTT obtained during the early stage of a corona radiata infarct seems to be helpful in predicting the motor outcome of the affected hand. 相似文献
97.
Implantation of bone marrow mononuclear cells using injectable fibrin matrix enhances neovascularization in infarcted myocardium 总被引:11,自引:0,他引:11
Ryu JH Kim IK Cho SW Cho MC Hwang KK Piao H Piao S Lim SH Hong YS Choi CY Yoo KJ Kim BS 《Biomaterials》2005,26(3):319-326
Neovascularization may improve cardiac function and prevent further scar tissue formation in infarcted myocardium. A number of studies have demonstrated that bone marrow-derived cells have the potential to induce neovascularization in ischemic tissues. In this study, we hypothesized that implantation of bone marrow mononuclear cells (BMMNCs) using injectable fibrin matrix further enhances neovascularization in infarcted myocardium compared to BMMNC implantation without matrix. To test this hypothesis, infarction was induced in rat myocardium by cryoinjury. Three weeks later, rat BMMNCs were mixed with fibrin matrix and injected into the infarcted myocardium. Injection of either BMMNCs or medium alone into infarcted myocardium served as controls. Eight weeks after the treatments, histological analyses indicated that implantation of BMMNCs using fibrin matrix resulted in more extensive tissue regeneration in the infarcted myocardium compared to BMMNC implantation without matrix. Examination with fluorescence microscopy revealed that cells labeled with a fluorescent dye prior to implantation survived in the infarcted myocardium at 8 weeks of implantation. Importantly, implantation of BMMNCs using fibrin matrix resulted in much more extensive neovascularization in infarcted myocardium than BMMNC implantation without matrix. The microvessel density in infarcted myocardium was significantly higher (p < 0.05) when BMMNCs were implanted using fibrin matrix (350 +/- 22 microvessels/mm2) compared to BMMNC implantation without matrix (262 +/- 13 microvessels/mm2) and medium injection (76 +/- 9 microvessels/mm2). In addition, average internal diameter of microvessels was significantly larger (p < 0.05) in BMMNC implantation with fibrin matrix group (14.6 +/- 1.2 microm) than BMMNC implantation without matrix group (10.2 +/- 0.7 microm) and medium injection group (7.3 +/- 0.5 microm). These results suggest that fibrin matrix could serve as a cell implantation matrix that enhances neovascularization efficacy for myocardial infarction treatment. 相似文献
98.
Immunohistochemical analysis of Smac/DIABLO expression in human carcinomas and sarcomas 总被引:27,自引:0,他引:27
Yoo NJ Kim HS Kim SY Park WS Park CH Jeon H Jung ES Lee JY Lee SH 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2003,111(3):382-388
Second mitochondria-derived activator of caspases (Smac/DIABLO) is released from mitochondria into the cytosol during apoptosis, promoting caspase activation by neutralizing the inhibition of inhibitor of apoptosis proteins (IAPs) on caspases. Alteration of apoptosis is essential for cancer development, and cancer cell death by radiation and chemotherapy is largely dependent upon apoptosis. In this study, archival tissues of 100 carcinomas and 50 sarcomas from various origins were analyzed by immunohistochemistry for the expression of Smac/DIABLO. Smac/DIABLO immunoreactivity was seen in 62 of 100 (62%) carcinomas, including 42 of 60 stomach carcinomas, 7 of 10 colorectal carcinomas, 4 of 10 lung carcinomas, 7 of 10 ovarian carcinomas, and 2 of 10 prostate carcinomas. Smac/DIABLO is expressed in 11 of 50 (22%) sarcomas, including 2 of 8 malignant schwannomas, 5 of 11 rhabdomyosarcomas, 2 of 7 malignant fibrous histiocytomas, 1 of 6 leiomyosarcomas, 0 of 8 angiosarcomas, 0 of 8 liposarcomas, and 1 of 2 Ewing's sarcomas. These data demonstrated that Smac/DIABLO expression levels vary depending on the individual cancer types. Furthermore, the present study showed that many human cancers do not express Smac/DIABLO, and suggest that lack of Smac/DIABLO expression in the cancer cells may inhibit apoptosis, thereby promoting their survival. 相似文献
99.
Ki CS Lee WY Han DH Sung DH Lee KB Lee KA Cho SS Cho S Hwang H Sohn KM Choi YJ Kim JW 《Journal of human genetics》2002,47(9):473-477
Hereditary spastic paraplegia (HSP) is a group of clinically and genetically heterogeneous neurodegenerative disorders characterized
by slowly progressive spasticity and weakness of the lower extremities. Among eight loci linked with autosomal-dominant (AD)-HSP,
the SPG4 locus on chromosome 2p22 accounts for about 40% of all patients. Recently, mutations in a new member of the AAA protein family,
called spastin, have been identified as responsible for SPG4-linked AD-HSP. Here, we describe a novel missense mutation (c.1031T>A; I344K) in exon 7 of the SPG4 gene identified in a Korean family with typical clinical features of pure AD-HSP. The mutation affects the third amino acid
of the highly conserved AAA cassette domain, which is the most fore part of the domain altered by a missense mutation reported
so far. Clinical presentations of affected individuals carrying the I344K mutation were not different from those of pure AD-HSP
with SPG4 mutations reported previously. However, it is noteworthy that neither urinary dysfunction nor involvement of upper extremities
was noticed in this family. To our knowledge, this is the first report of genetically confirmed AD-HSP in Korea.
Received: February 20, 2002 / Accepted: May 21, 2002 相似文献
100.
Galactosylated chitosan as a synthetic extracellular matrix for hepatocytes attachment 总被引:10,自引:0,他引:10
Galactose moiety as the hepatocyte anchorage was covalently coupled with chitosan for the development of synthetic extracellular matrix. Hepatocytes adhesion to galactosylated chitosan (GC)-coated polystyrene (PS) dish became as high as 94.7% after 2 h incubation whereas the hepatocytes adhesion to chitosan-coated PS dish was 69.1%, indication of galactose-specific recognition between GC molecules and asialoglycoprotein receptors of hepatocytes. The DNA synthesis of the hepatocytes adhered to GC-coated dish was increased in the presence of epidermal growth factor (EGF) at low concentration of GC (0.05 microg/ml) whereas the DNA synthesis of the hepatocytes adhered to GC-coated dish was decreased in the presence of EGF at high concentration of GC (5 microg/ml). The spreading shapes of the hepatocytes adhered to the surface in the presence of EGF at low concentration of GC (0.05 microg/ml) were enhanced than in the absence of EGF. The hepatocytes adhered to the surface at high concentration of GC (5 microg/ml) showed round shapes and exhibited many spheroid formation after 24 h in the presence of EGF. 相似文献