全文获取类型
收费全文 | 38873篇 |
免费 | 3599篇 |
国内免费 | 2225篇 |
专业分类
耳鼻咽喉 | 326篇 |
儿科学 | 618篇 |
妇产科学 | 382篇 |
基础医学 | 4157篇 |
口腔科学 | 714篇 |
临床医学 | 4793篇 |
内科学 | 5119篇 |
皮肤病学 | 572篇 |
神经病学 | 1689篇 |
特种医学 | 1521篇 |
外国民族医学 | 7篇 |
外科学 | 3359篇 |
综合类 | 7224篇 |
现状与发展 | 11篇 |
一般理论 | 2篇 |
预防医学 | 3591篇 |
眼科学 | 678篇 |
药学 | 4533篇 |
36篇 | |
中国医学 | 2720篇 |
肿瘤学 | 2645篇 |
出版年
2024年 | 141篇 |
2023年 | 499篇 |
2022年 | 1300篇 |
2021年 | 1787篇 |
2020年 | 1359篇 |
2019年 | 1129篇 |
2018年 | 1180篇 |
2017年 | 1218篇 |
2016年 | 1179篇 |
2015年 | 1823篇 |
2014年 | 2220篇 |
2013年 | 2481篇 |
2012年 | 3425篇 |
2011年 | 3687篇 |
2010年 | 2685篇 |
2009年 | 2147篇 |
2008年 | 2511篇 |
2007年 | 2466篇 |
2006年 | 2177篇 |
2005年 | 1890篇 |
2004年 | 1473篇 |
2003年 | 1422篇 |
2002年 | 1195篇 |
2001年 | 891篇 |
2000年 | 662篇 |
1999年 | 427篇 |
1998年 | 242篇 |
1997年 | 209篇 |
1996年 | 154篇 |
1995年 | 136篇 |
1994年 | 119篇 |
1993年 | 72篇 |
1992年 | 85篇 |
1991年 | 68篇 |
1990年 | 45篇 |
1989年 | 38篇 |
1988年 | 26篇 |
1987年 | 23篇 |
1986年 | 17篇 |
1985年 | 10篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1981年 | 4篇 |
1979年 | 21篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1970年 | 4篇 |
1969年 | 6篇 |
1968年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
51.
显性遗传性运动感觉性神经病Ⅱ型一个家系分析 总被引:1,自引:0,他引:1
目的本文报道一个在老年期发病的遗传性运动感觉性周围神经病Ⅱ型家族。方法对家族成员进行临床和电生理检查,其中1例病人进行腓肠神经活检。结果家族成员在老年期出现四肢无力和感觉减退。老年病人和无症状年轻病人的电生理检查均发现周围神经的诱发电位波幅显著下降。腓肠神经活检证实轴索性周围神经病。结论检查结果符合显性遗传性运动感觉性周围神经病Ⅱ型的诊断,电生理检查可以发现家族中的亚临床病人。 相似文献
52.
The present study was designed to evaluate whether functional impairment and/or protein expression of constitutive nitric oxide synthase (cNOS; endothelial NOS [eNOS] and neuronal NOS[nNOS]) was involved in impairment of endothelium-dependent relaxation of cavernous smooth muscle in hypercholesterolemic rabbits. New Zealand White rabbits were randomly divided into control and experimental groups. The control group (n=20) received a regular diet, while the two experimental groups (n=20 for each) were fed a 2% cholesterol diet for 4 and 8 weeks, respectively. We conducted isometric tension studies with endothelium-dependent and endothelium-independent vasodilators with or without preincubation with L-arginine and nonadrenergic, noncholinergic (NANC)-selective electrical field stimulation on isolated strips of corpus cavernosum. Expression of cNOS (eNOS and nNOS) protein was assessed by Western blot analysis. cNOS activities in both cytosolic and particulate fractions were measured by determining the conversion of L-[U-14C] arginine to L-[U-14C] citrulline. Blood levels of cholesterol were significantly higher (P < 0.01) in the experimental groups than in the control group. The relaxation responses to endothelium-dependent agents (acetylcholine and adenosine 5'-diphosphate [ADP]) were significantly reduced (P < 0.05) in both experimental groups, regardless of their incubation with L-arginine, compared with the control group. However, no differences were found among the three groups in the relaxation response to endothelium-independent agents (papaverine and nitroprusside) and to NANC-selective electrical field stimulation. There was no difference in immunoreactive nNOS from cytosolic and particulate fractions between the cavernous tissues of the control and experimental groups. nNOS protein levels in the particulate fractions were markedly lower than in the cytosolic fractions. The particulate cNOS activity was significantly decreased (P < 0.05) in the experimental groups compared with the control group, while the cytosolic cNOS activity in the experimental groups was not different from that found in the control group. Therefore, it is concluded that functional impairment of eNOS, rather than of nNOS, may lead to impairment of cavernous smooth muscle relaxation in response to endothelium-mediated stimuli in hypercholesterolemic rabbits. 相似文献
53.
An antioxidant lignan and other constituents from the root bark of Hibiscus syriacus 总被引:2,自引:0,他引:2
A new lignan named as hibiscuside, (+)-pinoresinol 4-O-[beta-glucopyranosyl (1--->2)-alpha-rhamnoside] (1), and a known lignan, syringaresinol (2) were isolated from the root bark of Hibiscus syriacus together with two feruloyltyramines (3,4) and three known isoflavonoids (5,6,7). The structures of these compounds have been established on the basis of their NMR, mass UV spectra. Among these phenolic compounds, 6"-O-acetyldaidzin (5), 6"-O-acetylgenistin (6), and 3-hydroxydaidzein (7) with IC(50) values of 8.2, 10.6, and 4.1 microM, respectively, significantly inhibited lipid peroxidation in rat liver microsomes. Hibiscuside (1), E- and Z-N-feruloyl tyramines (3,4) exhibited moderate antioxidant activity. 相似文献
54.
The mammary gland is a hormone-target organ derived from epidermis and develops as a result of reciprocal mesenchymal-epithelial interactions. The induction of mammary differentiation from indifferent epidermal cells by mammary mesenchyme implies induction of the complement of hormone receptors characteristic of normal mammary epithelium in cells of the epidermis. Considering the facts that mammary epithelial differentiation is induced by mammary mesenchyme and that certain aspects of hormone response (androgen-induced mammary regression) are inextricably linked to mesenchymal-epithelial interactions, it is evident that the biology of the mammary gland arises from and is maintained via cell-cell interactions. As a corollary, perturbation of stromal-epithelial interactions in adulthood may play a role in mammary carcinogenesis and in turn may provide opportunities for differentiation therapy. 相似文献
55.
Corneal permeability of variousn-alkylp-hydroxybenzoates (parabens) was studiedin vitro using excised rabbit corneas, and the effect of lipophilicity of parabens on the corneal permeability was also investigated. Permeability coefficients were obtained from the least-square linear regression after the steady state had been reached. Lipophilicity of parabens was calculated by distribution coefficients determined in octanol-S \(12_\phi [\kern-0.15em[ \) rensen’s buffer solution (pH 5.0). The relationship between lipophilicity and corneal permeability of parabens was not linear, but the optimum lipophilicity for the maximum permeation was found. The influence of tween 80 on corneal permeability of methyl and butylparaben was not significant. 相似文献
56.
山莨菪碱对妊娠高血压综合征子宫胎盘血流影响 总被引:1,自引:0,他引:1
目的:观察山莨菪碱对妊娠高血压综合征(妊高征)子宫动脉、脐动脉血流的短期影响.方法:妊高征患者14例给予山莨菪碱10~20 mg加入5%葡萄糖溶液500 mL中,静脉滴注,观察用药前后血压、体重、蛋白尿变化,多普勒超声监测用药前后子宫动脉、脐动脉的收缩期峰值(S)/舒张末期血流速度(D)(S/D),阻力指数(RI)、搏动指数(PI).结果:用药后收缩压及舒张压明显下降(P<0.05);水肿、蛋白尿减轻或消退;子宫动脉和脐动脉的S/D、RI、PI均明显下降(P<0.01).结论:山莨菪碱治疗妊高征能降低子宫、胎盘血流阻力,增加其血流灌注,同时改善孕妇临床症状,有利于母婴预后. 相似文献
57.
58.
Young Ho Yun Chang Geol Lee Si-young Kim Sang-wook Lee Dae Seog Heo Jun Suk Kim Keun Seok Lee Young Seon Hong Jung Suk Lee Chang Hoon You 《Journal of clinical oncology》2004,22(2):307-314
PURPOSE:To ascertain the attitude of cancer patients and their families toward disclosure of terminal illness to the patient. PATIENTS AND METHODS: We constructed a questionnaire that included demographic and clinical information and delivered it to 758 consecutive individuals (433 cancer patients and 325 families that have a relative with cancer) at seven university hospitals and one national cancer center in Korea. RESULTS: 380 cancer patients and one member from each of 281 families that have a relative with cancer completed the questionnaire. Cancer patients were more likely than family members to believe that patients should be informed of the terminal illness (96.1% v 76.9%; P <.001). Fifty percent of the family members and 78.3% of the patients thought that the doctor in charge should be the one who informs the patient. Additionally, 71.7% of the patients and 43.6% of the family members thought that patients should be informed immediately after the diagnosis. Stepwise multiple logistic regression indicated that the patient group was more likely than the family group to want the patient to be informed of the terminal illness (odds ratio [OR], 9.76; 95% CI, 4.31 to 22.14), by the doctor (OR, 4.00; 95% CI, 2.61 to 6.11), and immediately after the diagnosis (OR, 3.64; 95% CI, 2.45 to 5.41). CONCLUSION: Our findings indicated that most cancer patients want to be informed if their illness is terminal, and physicians should realize that the patient and the family unit may differ in their attitude toward such a disclosure. Our results also reflect the importance of how information is given to the patient. 相似文献
59.
Intravenous RNA interference gene therapy targeting the human epidermal growth factor receptor prolongs survival in intracranial brain cancer. 总被引:22,自引:0,他引:22
Yun Zhang Yu-Feng Zhang Joshua Bryant Andrew Charles Ruben J Boado William M Pardridge 《Clinical cancer research》2004,10(11):3667-3677
PURPOSE: The human epidermal growth factor receptor (EGFR) plays an oncogenic role in solid cancer, including brain cancer. The present study was designed to prolong survival in mice with intracranial human brain cancer with the weekly i.v. injection of nonviral gene therapy causing RNA interference (RNAi) of EGFR gene expression. EXPERIMENTAL DESIGN: Human U87 gliomas were implanted in the brain of adult scid mice, and weekly i.v. gene therapy was started at day 5 after implantation of 500000 cells. An expression plasmid encoding a short hairpin RNA directed at nucleotides 2529-2557 within the human EGFR mRNA was encapsulated in pegylated immunoliposomes. The pegylated immunoliposome was targeted to brain cancer with 2 receptor-specific monoclonal antibodies (MAb), the murine 83-14 MAb to the human insulin receptor and the rat 8D3 MAb to the mouse transferrin receptor. RESULTS: In cultured glioma cells, the delivery of the RNAi expression plasmid resulted in a 95% suppression of EGFR function, based on measurement of thymidine incorporation or intracellular calcium signaling. Weekly i.v. RNAi gene therapy caused reduced tumor expression of immunoreactive EGFR and an 88% increase in survival time of mice with advanced intracranial brain cancer. CONCLUSIONS: Weekly i.v. nonviral RNAi gene therapy directed against the human EGFR is a new therapeutic approach to silencing oncogenic genes in solid cancers. This is enabled with a nonviral gene transfer technology that delivers liposome-encapsulated plasmid DNA across cellular barriers with receptor-specific targeting ligands. 相似文献
60.
Objective Discussion of diagnosis, treatment and prognosis of non-palpable TO breast cancer.
Methods Between 1978 and 1997, 9,980 female patients with operable breast cancer were treated surgically, of which 276 were determined
to have TO breast cancer. Most TO breast cancers could be detected promptly with careful examination of presenting symptoms,
such as nipple discharge, local thickening of the breast, nipple erosion, nipple retraction and postmenopausal mastalgia,
while 12 cases were detected by routine mammography of the contralateral breast.
Results All patients were treated surgically and their tissue subjected to histopathological examination. Most cases (73.0%) were
noninvasive or early invasive carcinoma. Axillary lymph nodes metastases were found in 7.69% of 234 mastectomy cases.
Conclusion The survival rate was significantly increased if the tumor was in an early stage. The 5-, 10-, 15-years survival rates were
98.1%, 94.6% and 90.3%, respectively. 相似文献