全文获取类型
收费全文 | 23678篇 |
免费 | 1287篇 |
国内免费 | 282篇 |
专业分类
耳鼻咽喉 | 472篇 |
儿科学 | 303篇 |
妇产科学 | 268篇 |
基础医学 | 4299篇 |
口腔科学 | 556篇 |
临床医学 | 1893篇 |
内科学 | 4494篇 |
皮肤病学 | 890篇 |
神经病学 | 1800篇 |
特种医学 | 1320篇 |
外科学 | 2939篇 |
综合类 | 137篇 |
现状与发展 | 1篇 |
一般理论 | 5篇 |
预防医学 | 1066篇 |
眼科学 | 450篇 |
药学 | 2098篇 |
中国医学 | 284篇 |
肿瘤学 | 1972篇 |
出版年
2023年 | 149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 | 730篇 |
2015年 | 1081篇 |
2014年 | 1292篇 |
2013年 | 1431篇 |
2012年 | 2156篇 |
2011年 | 2042篇 |
2010年 | 1156篇 |
2009年 | 1042篇 |
2008年 | 1445篇 |
2007年 | 1343篇 |
2006年 | 1139篇 |
2005年 | 1010篇 |
2004年 | 862篇 |
2003年 | 751篇 |
2002年 | 646篇 |
2001年 | 570篇 |
2000年 | 470篇 |
1999年 | 395篇 |
1998年 | 155篇 |
1997年 | 117篇 |
1996年 | 90篇 |
1995年 | 94篇 |
1994年 | 63篇 |
1993年 | 45篇 |
1992年 | 143篇 |
1991年 | 148篇 |
1990年 | 112篇 |
1989年 | 123篇 |
1988年 | 103篇 |
1987年 | 108篇 |
1986年 | 95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 15 毫秒
991.
Hong SM Cho H Moskaluk CA Frierson HF Yu E Ro JY 《American journal of clinical pathology》2005,124(3):361-370
Although CDX2-mediated intestinal metaplasia and its association with gastric and esophageal carcinoma have been well described, its function in extrahepatic bile duct (EBD) carcinoma remains unclear. CDX2 and MUC2 expression were examined in 193 EBD carcinomas, and observed in 37.3% and 42.0%, respectively. Both CDX2 and MUC2 were observed in 27.4%. CDX2 (P<.001) and MUC2 (P<.001) were correlated with histologic subtypes and present, respectively, in all intestinal-type adenocarcinomas and mucinous carcinomas, 12 (71%) and 13 (76%) of 17 papillary carcinomas, 2 (40%) and 2 (40%) of 5 adenosquamous carcinomas, and 28.4% and 33.5% of adenocarcinomas, not otherwise specified. CDX2 was observed more frequently in tumors with papillary growth (P=.03) and no vascular invasion (P=.04), whereas MUC2 was more common in cases with low stage (P=.01) and no vascular invasion (P<.001). Patients with CDX2+/MUC2+ tumors had significantly better overall survival in univariate but not multivariate analysis than patients with other tumors (P<.05). Expression of CDX2 and MUC2 supports that intestinal differentiation is present in specific subtypes of EBD carcinomas, and their expression status correlates with patients' overall survival. 相似文献
992.
Chae HJ Kim HR Lee WG Kwak YK Kim WH Hong ST Cho GH Kim JS Chae SW 《Immunopharmacology and immunotoxicology》2005,27(2):211-232
Combined radiotherapy and chemotherapy have represented major advance in the therapeutic management of cancer therapy. Anthracycline antineoplastic agents are limited by a high incidence of severe and usually irreversible cardiac toxicity, the cause of which remains controversial. When the primary cardiomyocytes isolated from neonatal rats were preirradiated by γ-ray, the cells were highly resistant to adriamycin-induced apoptosis. This study shows that irradiation inhibited apoptosis by enhancing Bcl-2, attenuating Bax induction, and preventing collapse of mitochondrial membrane potential (ΔΨ), cytochrome c release into cytoplasm and caspase-3, -6 and -9 activations.
In addition, the preirradiation stimulated the activity of manganese-superoxide dismutase (Mn-SOD) and the expression of Mn-SOD mRNA and protein. Adriamycin decreased Mn-SOD activity but did not change the activity of copper/zinc (Cu/Zn)-SOD under either pre- or nonirradiated condition. Phosphothioate-linked antisense against Mn-SOD, which specifically knocked down the activity of Mn-SOD but not that of Cu/Zn-SOD, reversed irradiation-induced protective effect in adriamycin-exposed cardiomyocytes. These data suggest that the irradiation-induced expression of Mn-SOD plays an important role in irradiation-mediated protection in adriamycin-exposed rat ventricular cardiomyocytes. 相似文献
In addition, the preirradiation stimulated the activity of manganese-superoxide dismutase (Mn-SOD) and the expression of Mn-SOD mRNA and protein. Adriamycin decreased Mn-SOD activity but did not change the activity of copper/zinc (Cu/Zn)-SOD under either pre- or nonirradiated condition. Phosphothioate-linked antisense against Mn-SOD, which specifically knocked down the activity of Mn-SOD but not that of Cu/Zn-SOD, reversed irradiation-induced protective effect in adriamycin-exposed cardiomyocytes. These data suggest that the irradiation-induced expression of Mn-SOD plays an important role in irradiation-mediated protection in adriamycin-exposed rat ventricular cardiomyocytes. 相似文献
993.
Serial assessment of myocardial properties using cyclic variation of integrated backscatter in an adriamycin-induced cardiomyopathy rat model 总被引:2,自引:0,他引:2
Ha JW Kang SM Pyun WB Lee JY Ahn MY Kang WC Jeon TJ Chung N Lee JD Cho SH 《Yonsei medical journal》2005,46(1):73-77
Although adriamycin (Doxorubicin) is one of the most effective and useful antineoplastic agents for the treatment of a variety of malignancies, its repeated administration can induce irreversible myocardial damage and resultant heart failure. Currently, no marker to detect early cardiac damage is available. The purpose of this study was to investigate whether an assessment of the acoustic properties of the myocardium could enable the earlier detection of myocardial damage after adriamycin chemotherapy. Forty Wistar rats were treated with adriamycin (2 mg/kg, i.v.) once a week for 2, 4, 6 or 8 weeks consecutively. Left ventricular ejection fraction (LVEF) was calculated using M-mode echocardiography data. The magnitude of cardiac cycle dependent variation of integrated backscatter (CVIB) of the myocardium was measured in the mid segment of the septum and in the posterior wall of the left ventricle, using a real time two dimensional integrated backscatter imaging system. LVEF was significantly lower in the adriamycin-treated 8-week group than in the controls (75+/-9 vs 57+/-8%, p<0.05). Myocyte damage was only seen in the 8-week adriamycin-treated group. However, no significant changes of CVIB were observed between baseline or during follow-up in the ADR or control group. In conclusion, serial assessment of the acoustic properties of the myocardium may not be an optimal tool for the early detection of myocardial damage after doxorubicin chemotherapy in a rat model. 相似文献
994.
Rgs1 and Gnai2 regulate the entrance of B lymphocytes into lymph nodes and B cell motility within lymph node follicles 总被引:8,自引:0,他引:8
Signaling by G protein-coupled receptors coupled to Galpha(i) assists in triggering lymphocyte movement into and out of lymph nodes. Here, we show that modulating the signaling output from these receptors dramatically alters B cell trafficking. Intravital microscopy of adoptively transferred B cells from wild-type and Rgs1-/- mice revealed that Rgs1-/- B cells stick better to lymph node high endothelial venules, home better to lymph nodes, and move more rapidly within lymph node follicles than do wild-type B cells. In contrast, B cells from Gnai2-/- mice enter lymph nodes poorly and move more slowly than do wild-type B cells. The Gnai2-/- mice often lack multiple peripheral lymph nodes, and their B cells respond poorly to chemokines, indicating that Galpha(i1) and Galpha(i3) poorly compensate for the loss of Galpha(i2). These results demonstrate opposing roles for Rgs1 and Gnai2 in B cell trafficking into and within lymph nodes. 相似文献
995.
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
996.
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
997.
Kim YS Cheon KA Kim BN Chang SA Yoo HJ Kim JW Cho SC Seo DH Bae MO So YK Noh JS Koh YJ McBurnett K Leventhal B 《Yonsei medical journal》2004,45(1):81-89
In order to develop a structured and objective diagnostic instrument, authors completed: (1) the translation and back translation of the Korean version of the Kiddie-Schedule for Affective Disorders and Schizophrenia - Present and Lifetime Version (K-SADS-PL) and (2) the examination of its validity and reliability of the K-SADS-PL-Korean version (K-SADS- PL) when used with Korean children. A total of 91 study subjects were recruited from child and adolescent psychiatry outpatient clinics. Clinical diagnoses were used as a gold standard for the examination of validity of K-SADS-PL-K. Consensual validity of threshold and sub-threshold diagnoses were good to excellent for attention-deficit/hyperactivity disorder (ADHD), fair for tic and oppositional defiant disorders, and poor to fair for anxiety and depressive disorders. Inter-rater and test-retest reliabilities were fair to excellent for ADHD and tic disorder. The significant correlations between the K-SADS-PL-K and Korean Child Behavior Checklist (K-CBCL) were found, which provided additional support for the concurrent validity of the K-SADS-PL-K. Sensitivities varied according to the diagnostic categories, but specificities remained high over all diagnoses, suggesting that the K-SADS-PL-K is a desirable confirmatory diagnostic tool. The results of this study suggest that the K-SADS-PL-K is an effective instrument for diagnosing major child psychiatric disorders, including ADHD, behavioral disorders and tic disorders in Korean children. Future studies will examine the validity and reliability of the K-SADS-PL-K in larger samples, including adolescents and community samples on a variety of child and adolescent psychiatric disorders. 相似文献
998.
Tumor necrosis factor-alpha induces fractalkine expression preferentially in arterial endothelial cells and mithramycin A suppresses TNF-alpha-induced fractalkine expression 总被引:1,自引:0,他引:1 下载免费PDF全文
999.
Description of the transcriptomes of immune response-activated hemocytes from the mosquito vectors Aedes aegypti and Armigeres subalbatus 总被引:3,自引:0,他引:3 下载免费PDF全文
1000.
Kim Y Kim CK Cho BH Son HH Um CM Kim OY 《Journal of biomedical materials research. Part B, Applied biomaterials》2004,70(1):82-90
The applications of dental restorative composite resins containing 2,2 bis [4-(2-hydroxy-3-methacryloyloxy propoxy) phenyl] propane (Bis-GMA), as a base resin, and triethylene glycol dimethacrylate (TEGDMA), as a diluent, are often limited in dentistry due to the relatively large amount of volumetric shrinkage that occurs during the curing reaction. In this study, various new resin matrices were examined for use as dental composites in order to reduce the amount of volumetric shrinkage that occurs in dental composites as a result of curing. Bis-GMA derivatives were synthesized by substituting methyl groups for hydrogen on the phenyl ring. The derivatives of TEGDMA with different chain lengths or reactive groups were also examined. The molecular structural changes in the TEGDMA derivatives were not effective in reducing the level of volumetric shrinkage. The resin matrix containing a Bis-GMA derivative and TEGDMA showed a reduced amount of volumetric shrinkage in proportion to the number of methyl groups on the phenyl rings. Polymerization with a mixture of Bis-GMA, its derivatives and a diluent is a promising strategy for obtaining a polymer with a low amount of volumetric shrinkage. A comparison of the volumetric shrinkage of dental composites containing Bis-GMA, TMBis-GMA (2,2-bis[3,5-dimethyl, 4-(2-hydroxy-3-methacryloyloxy propoxy) phenyl] propane)), and TEGDMA with that prepared from a Bis-GMA and TEGDMA mixture showed that the volumetric shrinkage reduction in the new resin was approximately 50%. Furthermore, the mechanical strength of the former was higher than that of the latter. 相似文献