全文获取类型
收费全文 | 229651篇 |
免费 | 20916篇 |
国内免费 | 15496篇 |
专业分类
耳鼻咽喉 | 2033篇 |
儿科学 | 2422篇 |
妇产科学 | 3181篇 |
基础医学 | 27748篇 |
口腔科学 | 3952篇 |
临床医学 | 32001篇 |
内科学 | 34615篇 |
皮肤病学 | 2299篇 |
神经病学 | 13419篇 |
特种医学 | 8582篇 |
外国民族医学 | 138篇 |
外科学 | 23480篇 |
综合类 | 35485篇 |
现状与发展 | 55篇 |
一般理论 | 30篇 |
预防医学 | 14156篇 |
眼科学 | 6849篇 |
药学 | 23266篇 |
194篇 | |
中国医学 | 12386篇 |
肿瘤学 | 19772篇 |
出版年
2024年 | 700篇 |
2023年 | 3596篇 |
2022年 | 9265篇 |
2021年 | 11721篇 |
2020年 | 8702篇 |
2019年 | 7757篇 |
2018年 | 8203篇 |
2017年 | 7267篇 |
2016年 | 6818篇 |
2015年 | 10454篇 |
2014年 | 12823篇 |
2013年 | 11125篇 |
2012年 | 16604篇 |
2011年 | 18576篇 |
2010年 | 10855篇 |
2009年 | 8493篇 |
2008年 | 11690篇 |
2007年 | 11745篇 |
2006年 | 11904篇 |
2005年 | 11998篇 |
2004年 | 7649篇 |
2003年 | 7229篇 |
2002年 | 6065篇 |
2001年 | 5031篇 |
2000年 | 5430篇 |
1999年 | 5783篇 |
1998年 | 3656篇 |
1997年 | 3614篇 |
1996年 | 2894篇 |
1995年 | 2697篇 |
1994年 | 2226篇 |
1993年 | 1450篇 |
1992年 | 1955篇 |
1991年 | 1647篇 |
1990年 | 1341篇 |
1989年 | 1137篇 |
1988年 | 1059篇 |
1987年 | 934篇 |
1986年 | 764篇 |
1985年 | 582篇 |
1984年 | 387篇 |
1983年 | 302篇 |
1982年 | 213篇 |
1981年 | 207篇 |
1980年 | 171篇 |
1979年 | 185篇 |
1978年 | 99篇 |
1977年 | 92篇 |
1975年 | 88篇 |
1973年 | 84篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
复合式听写比听力选择题更强调语言综合运用能力。全面打好语言基本功是提高听写能力的重要途径。但听写训练具有自身的科学性和技巧性,多练加巧练可以取得事半功倍的成效。 相似文献
82.
83.
刘伯宁 《中国实用妇科与产科杂志》2006,22(5):338-339
卵巢肿瘤合并副肿瘤性综合征(ovarian tumor associated with paraneoplastic syndrome)并非罕见,但由于此综合征往往先于肿瘤出现,而因肿瘤病灶小或隐匿不易被发现,常被临床医师所忽略,导致肿瘤未能得到及时诊断和治疗."paraneoplastic syndrome"一词有译为副肿瘤性综合征、副肿瘤综合征、副癌综合征、肿瘤外综合征者.此综合征为肿瘤患者的一种复合症状,该症状不能用肿瘤本身或肿瘤转移来解释.现按主要受累系统的几种综合征简介如下,以加强临床医师对卵巢肿瘤合并副肿瘤性综合征特点的认识,减少误诊、误治。 相似文献
84.
Chuan-Bin Guo Nian-Hui Cui Guang-Yan Yu Ding-Xin Liu Shu-Cong Meng Qing Song 《Journal of oral and maxillofacial surgery》2003,61(8):909-912
PURPOSES: Inhibition of cerulenin on the endogenous fatty acid synthetic activities of oral squamous cell carcinoma (OSCC) and normal oral mucosa was assayed. METHODS: Squamous cell carcinoma and normal oral mucosa were collected fresh from surgical specimens. The collected tissues were minced in RPMI 1640 and divided into 3 groups: cerulenin treated, dimethylsulfoxide treated, and control. The tissues were incubated in [1(2)-(14)C]acetic acid, sodium salt for the last 2.5 hours of the treatment at 37 degrees C in 5% CO(2). After labeling, total lipids were extracted and counted for (14)C by scintillation counting. RESULTS: Endogenous fatty acid synthetic activities of oral squamous cell caranoma in the cerulenin-treated group decreased by 19% at 1 hour, 64% at 2 hours, and 87% at 4 hours; remained nearly unchanged in the dimethylsulfoxide-treated group; and increased slightly in the control group. The oral mucosa tissues were only mildly affected by cerulenin in fatty acid synthesis. CONCLUSIONS: Cerulenin significantly inhibits fatty acid synthetic activity in squamous cell carcinoma and only mildly affected the oral mucosa, indicating that the fatty acid synthetic pathway may be exploited as a target for developing anticancer drugs. 相似文献
85.
Noah A Goldman Ellen B Katz Alan S Glenn Richard H Weldon Joan G Jones Uticia Lynch Melissa J Fezzari Carolyn D Runowicz Gary L Goldberg Maureen J Charron 《Modern pathology》2006,19(11):1429-1436
Glucose is provided to cells by a family of glucose transport facilitators known as GLUTs. These transporters are expressed in a tissue specific manner and are overexpressed in many primary tumors of these tissues. Regulation of glucose transport facilitator expression has been demonstrated in endometrial tissue and endometrial adenocarcinoma. The following experiments were conducted to quantify and localize the expression of GLUT1 and GLUT8 in benign endometrium and compare this expression to endometrial cancer. Endometrial tissue samples were obtained from random hysterectomy specimens of patients with benign indications for surgery and endometrial cancer. Immunoblot and immunolocatization studies were performed using GLUT1 and GLUT8 specific antisera. Endometrial samples from 65 women who had undergone hysterectomy were examined (n=38 benign, n=27 malignant). A 44 and a 35.4 kDa immunoreacive species was demonstrated in endometrium and endometrial cancer for GLUT1 and GLUT8, respectively. Upregulation of GLUT1 expression was demonstrated with increasing grade of tumors (P<0.002). GLUT8 expression was increased in all tumor subtypes compared to atrophic endometrium (P<0.001). Apical localization by GLUT1 and GLUT8 was demonstrated in endometrial glands. GLUT1 and GLUT8 demonstrated diffuse intracellular localization in the cancer subtypes. GLUT1 and GLUT8 are expressed in both human endometrium and endometrial cancer. There appears to be a step-wise progression in GLUT1 and GLUT8 expression as tumor histopathology worsens. GLUT1 and GLUT8 may be important markers in tumor differentiation, as well as providing energy to rapidly dividing tumor cells. 相似文献
86.
刘小军 《四川省卫生管理干部学院学报》2004,23(4):313-314
重组α-2b干扰素是具有抗病毒和免疫调节作用的生物学调节活性物质。近年来,国外文献报道α-2b干扰素治疗慢性乙型病毒性肝炎(CAH—B)取得较好效果。特别是基因工程问世,使大量的高纯度干扰素应用于临床。现对48例慢性乙肝患者使用干扰素后的不良反应的观察与护理,报道如下。 相似文献
87.
Z-Y Sun J Wei L Xie Y Shen S-Z Liu G-Z Ju J-P Shi Y-Q Yu X Zhang Q Xu G P Hemmings 《European psychiatry》2004,19(6):354-357
The present study was designed to detect three single nucleotide polymorphisms (SNPs) located on 22q11 that was thought as being of particularly importance for genetic research into schizophrenia. We recruited a total of 176 Chinese family trios of Han descent, consisting of mothers, fathers and affected offspring with schizophrenia for the genetic analysis. The transmission disequilibrium test (TDT) showed that of three SNPs, rs10314 in the 3'-untranslated region of the CLDN5 locus was associated with schizophrenia (chi(2) = 4.75, P = 0.029). The other two SNPs, rs1548359 present in the CDC45L locus centromeric of rs10314 and rs739371 in the 5'-flanking region of the CLDN5 locus, did not show such an association. The global chi-square (chi(2)) test showed that the 3-SNP haplotype system was not associated with schizophrenia although the 1-df test for individual haplotypes showed that the rs1548359(C)-rs10314(G)-rs739371(C) haplotype was excessively non-transmitted (chi(2) = 5.32, P = 0.02). Because the claudin proteins are a major component for barrier-forming tight junctions that could play a crucial role in response to changing natural, physiological and pathological conditions, the CLDN5 association with schizophrenia may be an important clue leading to look into a meeting point of genetic and environmental factors. 相似文献
88.
Chen Li Liu Maryann E Martone Bingren R Hu 《Journal of cerebral blood flow and metabolism》2004,24(11):1219-1225
The mechanisms underlying neurologic deficits and delayed neuronal death after ischemia are not fully understood. In the present study, we report that transient cerebral ischemia induces accumulation of ubiquitinated proteins (ubi-proteins) in postsynaptic densities (PSDs). By immunoelectron microscopy, we demonstrated that ubi-proteins were highly accumulated in PSD structures after ischemia. On Western blots, ubi-proteins were markedly increased in purified PSDs at 30 minutes of reperfusion, and the increase persisted until cell death in the CA1 region after ischemia. In the resistant DG area, however, the changes were transient and significantly less pronounced. Deposition of ubi-proteins in PSDs after ischemia correlates well with PSD structural damage in the CA1 region as viewed by electron microscopy. These results suggest that the ubiquitin-proteasome system fails to repair and remove damaged proteins in PSDs. The changes may demolish synaptic neurotransmission, contribute to neurologic deficits, and eventually lead to delayed neuronal death after transient cerebral ischemia. 相似文献
89.
Laryngeal tuberculosis: a review of 26 cases. 总被引:2,自引:0,他引:2
Chen-Chi Wang Chang-Chun Lin Ching-Ping Wang Shih-An Liu Rong-San Jiang 《Otolaryngology--head and neck surgery》2007,137(4):582-588
OBJECTIVES: To review the clinical characteristics of laryngeal tuberculosis. STUDY DESIGN: Retrospective case series. SUBJECTS AND METHODS: Medical records of 26 histopathology-confirmed cases in a tertiary medical center from 1992 to 2006. RESULTS: The female patients were significantly younger than male patients. Hoarseness is the most common symptom (84.6%) because true vocal fold is most commonly involved (80.8%). Infection usually involves unilateral (66.7%) and right-side larynx but multiple subsites of the larynx (57.7%). The appearance of the affected larynx may have mixed features and change before diagnosis. Laryngeal tuberculosis is usually misdiagnosed as laryngeal cancer, especially in patients with malignant signs such as enlarged cervical lymph nodes and vocal fold immobility. Chest film is better than sputum examinations for screening. CONCLUSION: We should be especially alert about TB infection when facing young female patients with unusual laryngeal lesions. Extensive laser excision before diagnosis should be avoided because after antituberculous treatment, prognosis is usually good and vocal fold immobility could be reversible. 相似文献
90.
Examination of potential mechanism(s) of metallothionein induction by diethyl maleate. 总被引:1,自引:0,他引:1
J W Bauman Y P Liu G K Andrews C D Klaassen 《Toxicology and applied pharmacology》1992,117(2):226-232
Diethyl maleate (DEM) is a glutathione-depleting agent that can increase the levels of the sulfhydryl-rich protein metallothionein (MT) in liver. The purpose of the present study was to examine the mechanism(s) by which DEM increases mouse hepatic MT levels. DEM appears to be an indirect MT inducer as suggested by the lack of increase in MT levels when cultured mouse hepatocytes were exposed to DEM. Four possible mechanisms by which indirect MT inducers may cause an elevation in MT concentrations in liver were examined. Zn levels did not increase prior to the increase in hepatic MT, thus, a Zn redistribution to the liver is not the cause of the liver MT induction by DEM. The adrenal gland products were not required for MT induction in liver, as adrenalectomy did not abolish the increase in hepatic MT caused by DEM. The elevation in liver MT does not appear to be due solely to the decrease in liver glutathione (60%) in the initial hour after DEM, because phorone, which decreases liver glutathione (80%), produced only a fourfold increase in hepatic MT. Activation of macrophages does not seem to account for the rise in liver MT levels, as there was no increase in abundance of cytokine mRNAs for TNF-alpha, IL-1 beta, or IL-6 in the liver. These data suggest that the induction of hepatic MT by DEM does not occur in response to (1) an increase in liver Zn that precedes the increase in liver MT, (2) release of adrenal gland products, (3) decrease in liver glutathione, or (4) increased cytokine gene expression. 相似文献