全文获取类型
收费全文 | 59337篇 |
免费 | 5598篇 |
国内免费 | 4176篇 |
专业分类
耳鼻咽喉 | 651篇 |
儿科学 | 602篇 |
妇产科学 | 572篇 |
基础医学 | 6097篇 |
口腔科学 | 878篇 |
临床医学 | 7550篇 |
内科学 | 8044篇 |
皮肤病学 | 579篇 |
神经病学 | 2805篇 |
特种医学 | 2308篇 |
外国民族医学 | 36篇 |
外科学 | 6419篇 |
综合类 | 10982篇 |
现状与发展 | 13篇 |
一般理论 | 4篇 |
预防医学 | 4215篇 |
眼科学 | 1635篇 |
药学 | 6451篇 |
58篇 | |
中国医学 | 4271篇 |
肿瘤学 | 4941篇 |
出版年
2024年 | 264篇 |
2023年 | 903篇 |
2022年 | 2456篇 |
2021年 | 3054篇 |
2020年 | 2494篇 |
2019年 | 1932篇 |
2018年 | 2074篇 |
2017年 | 2044篇 |
2016年 | 1849篇 |
2015年 | 2942篇 |
2014年 | 3710篇 |
2013年 | 3381篇 |
2012年 | 4884篇 |
2011年 | 5232篇 |
2010年 | 3608篇 |
2009年 | 2924篇 |
2008年 | 3387篇 |
2007年 | 3136篇 |
2006年 | 3056篇 |
2005年 | 2816篇 |
2004年 | 1834篇 |
2003年 | 1741篇 |
2002年 | 1439篇 |
2001年 | 1187篇 |
2000年 | 1110篇 |
1999年 | 1055篇 |
1998年 | 655篇 |
1997年 | 587篇 |
1996年 | 483篇 |
1995年 | 454篇 |
1994年 | 344篇 |
1993年 | 260篇 |
1992年 | 314篇 |
1991年 | 307篇 |
1990年 | 210篇 |
1989年 | 163篇 |
1988年 | 185篇 |
1987年 | 156篇 |
1986年 | 101篇 |
1985年 | 80篇 |
1984年 | 60篇 |
1983年 | 32篇 |
1982年 | 29篇 |
1981年 | 31篇 |
1980年 | 23篇 |
1979年 | 38篇 |
1978年 | 13篇 |
1977年 | 11篇 |
1975年 | 11篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Liang B 《International journal of oncology》1995,7(3):611-615
Gene amplification is an important phenomenon in the pathogenetics of malignancy. A method is defined which allows the determination of gene amplification from any sample from which RNA can be obtained, and requires no a priori knowledge of the cytogenetic or genomic state of the tumor. This method allows the determination of various degrees of amplification, and is sensitive to lower degrees of increased copy number. Gene amplification from cell lines with known oncogene amplification of 13- and 7-fold could be detected. Hence, use of a simple modified subtractive hybridization technique can identify amplified cDNAs from tissue without detailed previous genomic knowledge of the samples. This methodology should prove useful in the assessment of disorders where copy number changes of expressed genes are present. 相似文献
93.
梁勇 《听力学及言语疾病杂志》1994,(4)
本文报道了11例病例,并以3例典型病例就肌源性耳鸣的声导抗测试的基本方法和特征作了探讨。腭肌阵挛的幅度较大,在鼓室导抗图和声反射曲线上均可出现锯齿状波。镫骨肌阵挛在表情肌运动时可诱发,为持续性,镫骨肌声反射对其无影响或可掩盖之。鼓膜张肌阵挛与面部三叉神经受刺激有关,易疲劳,表现为一短暂的声顺变化波形。 相似文献
94.
Fu YL Hu YX Ling HL Ye ZZ Liang T Zhang MG Liu YK Kang B Luo YJ He SY Lian YJ 《Infectious diseases in obstetrics and gynecology》1994,1(5):235-241
Objective: The objective of this study was to determine whether human papillomavirus (HPV) infections are involved in the development of papillomatosis lesions of the lower female genital tract.Methods: A total of 616 biopsy specimens of genital papillomatous lesions (307 nodular and 309 papular types) from 598 patients were anaylyzed for the presence of HPV DNA sequences by polymerase chain reaction (PCR). These specimens were also examined by histopathological assessment for characteristic HPV-associated cytological changes, by immunohistochemical staining for HPV-associated antigen, and by electron microscopy for the presence of virions.Results: HPV DNA sequences were found in 97.9% (140 of 143 cases) and 1.1% (1 of 91 cases) of the nodular and papular papillomatosis cases tested, respectively. In 18 patients who had both types of papillomatosis lesions, HPV DNA was invariably found only in nodular tissues. HPV-associated antigen, koilocytosis, and virions were found in 53.6% (98 of 183 cases), 70.5% (129 of 183 cases), and 5.9% (5 of 85 cases) of nodular papillomatosis lesions tested, respectively.Conclusions: These data suggest that nodular papillomatosis was closely associated with HPV infection, but that papular papillomatosis of the lower female genital tract may have an etiology other than HPV infection. 相似文献
95.
目的 分析我国消除丙型肝炎(丙肝)的普通人群HCV检测策略的成本效果,明确最佳成本效果的HCV检测年龄。方法 运用TreeAge pro 2019软件构建决策树马尔科夫模型,以1年为周期,模拟10万名20~59岁各年龄组人群HCV检测和治疗结果,以全社会角度分析策略间比较的成本效果和效益。效果指标为增量成本效果比(ICER),效益指标为净货币效益(NMB),以我国2022年人均国内生产总值(85 698元)为意愿支付阈值。通过单因素敏感性分析和概率敏感性分析评估结果可靠性。结果 在20~59岁人群HCV检测有成本效果,在40~49岁年龄组进行HCV检测成本效果最佳。20~59岁年龄组人群HCV检测策略与未HCV检测策略比较,增量成本为161.24元/人,增量效用为0.003 6质量调整寿命年(QALYs)/人,ICER为45 197.26元/QALY,ICER小于意愿支付阈值,具有成本效果。各年龄组人群HCV检测策略与未HCV检测策略比较,ICER为42 055.06~53 249.43元/QALY,NMB为96.52~169.86元/人,其中40~49岁年龄组的ICER最低,NMB最高。单因素敏感性分析结果显示,贴现率、丙肝抗体(抗-HCV)检测成本、人群抗-HCV阳性率和直接抗病毒药物治疗成本对经济学评价影响较大,但改变参数取值,结论不变。概率敏感性分析结果表明模型分析结果稳定。结论 医疗机构探索动员20~59岁普通人群进行HCV检测具有较好的成本效果,以40~49岁年龄组人群的HCV检测成本效果最佳。在我国普通人群中实施HCV检测的“愿检尽检”策略,能降低人群丙肝疾病负担。 相似文献
96.
目的探讨试剂对VCA-IgA抗体检测结果的影响.方法用不同厂家或同一厂家不同批号之试剂盒分别检测同一批血清或同一批人群不同时期血清的VCA-IgA,进行横向和纵向比较.结果①同一批血清用不同试剂盒检测结果完全相同占35.58%和35.59%,完全相反占15.38%和13.56%,差异一个滴度占28.85%和36.44%,差异二个滴度以上占20.19%和14.41%;②同一人群不同时期血清因用同一厂家不同批号试剂,所得结果完全相同占36.99%,完全相反占13.70%,差异一个滴度占32.88%,差异二个滴度以上占16.43%;③广东C试剂盒无论是检测同一批血清,还是检测同一批人不同时期血清,所得阳性率及其滴度均显著高于广西出品的试剂盒.结论①同一个人在不同时间、地点检测结果可能差异很大;②一个医院应相对稳定使用同一厂家试剂盒;③对比同一个人不同时期的抗体变化,应用同一批试剂同时检测,才具有良好的对比性. 相似文献
97.
The purpose of this study was to investigate possible adverse effects of cannabis use on cognitive decline after 12 years in persons under age 65 years. This was a follow-up study of a probability sample of the adult household residents of East Baltimore. The analyses included 1,318 participants in the Baltimore, Maryland, portion of the Epidemiologic Catchment Area study who completed the Mini-Mental State Examination (MMSE) during three study waves in 1981, 1982, and 1993-1996. Individual MMSE score differences between waves 2 and 3 were calculated for each study participant. After 12 years, study participants' scores declined a mean of 1.20 points on the MMSE (standard deviation 1.90), with 66% having scores that declined by at least one point. Significant numbers of scores declined by three points or more (15% of participants in the 18-29 age group). There were no significant differences in cognitive decline between heavy users, light users, and nonusers of cannabis. There were also no male-female differences in cognitive decline in relation to cannabis use. The authors conclude that over long time periods, in persons under age 65 years, cognitive decline occurs in all age groups. This decline is closely associated with aging and educational level but does not appear to be associated with cannabis use. 相似文献
98.
目的:探讨糖皮质激素治疗流行性乙型脑炎的疗效。方法:采用地塞米松针剂加入液体静脉滴注,并配合物理降温、镇静止痉、脱水、给氧、扩容、纠酸、防治感染,加强护理等常规综合治疗。结果:治愈69例(908%),好转3例(39%),死亡4例(53%)。结论:在常规综合治疗基础上应用激素治疗乙型脑炎疗效显著提高。 相似文献
99.
Shigematsu Y Korogi Y Hirai T Okuda T Sugahara T Liang L Takahashi M 《Journal of magnetic resonance imaging : JMRI》1999,10(6):939-944
This work investigated whether turbo magnetic resonance angiography (MRA) can replace conventional MRA in screening examination of intracranial arteries. A phantom was used to evaluate the effect of the zero-filling interpolation (ZFI) technique on spatial resolution and partial volume effect. Thirty-one consecutive patients underwent both turbo MRA with a slice thickness of 0.7 mm (data were measured as 1.33 mm sections) and conventional MRA with 1.0 mm sections. In the phantom studies, ZFI did not improve the spatial resolution, but the partial volume effect was somewhat reduced. In the clinical evaluation, turbo MRA showed better signal-to-noise and contrast-to-noise ratios of the intracranial major vessels than conventional MRA. The lesions included cerebral aneurysms less than 3 mm in diameter, occlusive vascular disease, arteriovenous malformations, and arteriovenous fistulas. These were all depicted on both turbo MRA and conventional MRA. Turbo MRA is a useful screening procedure because of its capability of delineating lesions in approximately half the usual imaging time. J. Magn. Reson. Imaging 1999;10:939-944. 相似文献
100.
Ambulatory urodynamic monitoring of external urethral sphincter behavior in chronic prostatitis patients 总被引:3,自引:0,他引:3
Aim: To study the behavior of external urethral sphincter in chronic prostatitis (CP) patient under natural filling.Methods: Twenty-one CP patients and 17 normal volunteers were involved in the study. Both the patients andvolunteers underwent ambulatory urodynamic monitoring (AM) and conventional medium filling cystometry (CMG).Urodec 500 was used for AM and Menuet for CMG. AM findings from CP patients were compared with those fromnormal volunteers, and the results from AM were compared with those from CMG. Results: In AM, the restingand voiding external urethral sphincter (EUS) pressures and maximum urethral closure pressures (MUCP) weresignificantly higher in CP patients [ ( 121.5 ±10.3) and (85.6±3.5) cm water, respectively ] than in normalvolunteers [ (77.6±11.4) and (10.3±1.6) cm water, respectively)]. Conclusion: The behavioral changes ofEUS in CP patients included spasm and instability of EUS, which were demonstrated using AM under natural filling;the findings were also in accord with the res 相似文献