全文获取类型
收费全文 | 1511816篇 |
免费 | 120168篇 |
国内免费 | 3585篇 |
专业分类
耳鼻咽喉 | 19927篇 |
儿科学 | 49642篇 |
妇产科学 | 43391篇 |
基础医学 | 214688篇 |
口腔科学 | 41374篇 |
临床医学 | 132469篇 |
内科学 | 309628篇 |
皮肤病学 | 36618篇 |
神经病学 | 125065篇 |
特种医学 | 56142篇 |
外国民族医学 | 465篇 |
外科学 | 223156篇 |
综合类 | 33323篇 |
现状与发展 | 3篇 |
一般理论 | 519篇 |
预防医学 | 120333篇 |
眼科学 | 33814篇 |
药学 | 105731篇 |
1篇 | |
中国医学 | 3851篇 |
肿瘤学 | 85429篇 |
出版年
2021年 | 13057篇 |
2019年 | 14126篇 |
2018年 | 20785篇 |
2017年 | 15116篇 |
2016年 | 16467篇 |
2015年 | 18477篇 |
2014年 | 25349篇 |
2013年 | 37707篇 |
2012年 | 53077篇 |
2011年 | 56071篇 |
2010年 | 32276篇 |
2009年 | 29909篇 |
2008年 | 50813篇 |
2007年 | 53800篇 |
2006年 | 53736篇 |
2005年 | 52130篇 |
2004年 | 49343篇 |
2003年 | 46883篇 |
2002年 | 45122篇 |
2001年 | 75451篇 |
2000年 | 77453篇 |
1999年 | 63720篇 |
1998年 | 17370篇 |
1997年 | 15666篇 |
1996年 | 15815篇 |
1995年 | 14967篇 |
1994年 | 13539篇 |
1993年 | 12707篇 |
1992年 | 46684篇 |
1991年 | 44193篇 |
1990年 | 42198篇 |
1989年 | 40115篇 |
1988年 | 36658篇 |
1987年 | 35824篇 |
1986年 | 33358篇 |
1985年 | 31688篇 |
1984年 | 24129篇 |
1983年 | 20264篇 |
1982年 | 12326篇 |
1981年 | 10883篇 |
1979年 | 20984篇 |
1978年 | 14759篇 |
1977年 | 12257篇 |
1976年 | 11537篇 |
1975年 | 11849篇 |
1974年 | 14257篇 |
1973年 | 13838篇 |
1972年 | 12891篇 |
1971年 | 11750篇 |
1970年 | 11174篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
65.
66.
67.
Krishna Pillai Javid Akhter Terence C. Chua Mena Shehata Nayef Alzahrani Issan Al-Alem David L. Morris 《Medicine》2015,94(9)
Thermal ablation of liver tumors near large blood vessels is affected by the cooling effect of blood flow, leading to incomplete ablation. Hence, we conducted a comparative investigation of heat sink effect in monopolar (MP) and bipolar (BP) radiofrequency ablation (RFA), and microwave (MW) ablation devices.With a perfused calf liver, the ablative performances (volume, mass, density, dimensions), with and without heat sink, were measured. Heat sink was present when the ablative tip of the probes were 8.0 mm close to a major hepatic vein and absent when >30 mm away. Temperatures (T1 and T2) on either side of the hepatic vein near the tip of the probes, heating probe temperature (T3), outlet perfusate temperature (T4), and ablation time were monitored.With or without heat sink, BP radiofrequency ablated a larger volume and mass, compared with MP RFA or MW ablation, with latter device producing the highest density of tissue ablated. MW ablation produced an ellipsoidal shape while radiofrequency devices produced spheres.Percentage heat sink effect in Bipolar radiofrequency : Mono-polar radiofrequency : Microwave was (Volume) 33:41:22; (mass) 23:56:34; (density) 9.0:26:18; and (relative elipscity) 5.8:12.9:1.3, indicating that BP and MW devices were less affected.Percentage heat sink effect on time (minutes) to reach maximum temperature (W) = 13.28:9.2:29.8; time at maximum temperature (X) is 87:66:16.66; temperature difference (Y) between the thermal probes (T3) and the temperature (T1 + T2)/2 on either side of the hepatic vessel was 100:87:20; and temperature difference between the (T1 + T2)/2 and temperature of outlet circulating solution (T4), Z was 20.33:30.23:37.5.MW and BP radiofrequencies were less affected by heat sink while MP RFA was the most affected. With a single ablation, BP radiofrequency ablated a larger volume and mass regardless of heat sink. 相似文献
68.
B.B. Damian T.C.S. Bonetti D.D.G. Horovitz 《Brazilian journal of medical and biological research》2015,48(1):25-33
Preimplantation genetic diagnosis (PGD) was originally developed to diagnose
embryo-related genetic abnormalities for couples who present a high risk of a
specific inherited disorder. Because this technology involves embryo selection, the
medical, bioethical, and legal implications of the technique have been debated,
particularly when it is used to select features that are not related to serious
diseases. Although several initiatives have attempted to achieve regulatory
harmonization, the diversity of healthcare services available and the presence of
cultural differences have hampered attempts to achieve this goal. Thus, in different
countries, the provision of PGD and regulatory frameworks reflect the perceptions of
scientific groups, legislators, and society regarding this technology. In Brazil,
several texts have been analyzed by the National Congress to regulate the use of
assisted reproduction technologies. Legislative debates, however, are not conclusive,
and limited information has been published on how PGD is specifically regulated. The
country requires the development of new regulatory standards to ensure adequate
access to this technology and to guarantee its safe practice. This study examined
official documents published on PGD regulation in Brazil and demonstrated how little
direct oversight of PGD currently exists. It provides relevant information to
encourage reflection on a particular regulation model in a Brazilian context, and
should serve as part of the basis to enable further reform of the clinical practice
of PGD in the country. 相似文献
69.
Zaida Araujo Sietze Brandes Elena Pinelli María A. Bochichio Andrea Palacios Albina Wide Bruno Rivas-Santiago Juan Carlos Jiménez 《Revista do Instituto de Medicina Tropical de S?o Paulo》2015,57(1):47-55
The present study aimed at measuring seropositivities for infection by
Ascaris suum and Toxocara canis using the
excretory/secretory (E/S) antigens from Ascaris suum (AES) and
Toxocara canis (TES) within an indigenous population. In
addition, quantification of cytokine expressions in peripheral blood cells was
determined. A total of 50 Warao indigenous were included; of which 43 were adults and
seven children. In adults, 44.1% were seropositive for both parasites; whereas
children had only seropositivity to one or the other helminth. For ascariosis, the
percentage of AES seropositivity in adults and children was high; 23.3% and 57.1%,
respectively. While that for toxocariosis, the percentage of TES seropositivity in
adults and children was low; 9.3% and 14.3%, respectively. The percentage of
seronegativity was comparable for AES and TES antigens in adults (27.9%) and children
(28.6%). When positive sera were analyzed by Western blotting technique using AES
antigens; three bands of 97.2, 193.6 and 200.2 kDas were mostly recognized. When the
TES antigens were used, nine major bands were mostly identified; 47.4, 52.2, 84.9,
98.2, 119.1, 131.3, 175.6, 184.4 and 193.6 kDas. Stool examinations showed that
Blastocystis hominis, Hymenolepis nana and
Entamoeba coli were the most commonly observed intestinal
parasites. Quantification of cytokines IFN-γ, IL-2, IL-6, TGF-β, TNF-α, IL-10 and
IL-4 expressions showed that there was only a significant increased expression of
IL-4 in indigenous with TES seropositivity (p < 0.002).
Ascaris and Toxocara seropositivity was
prevalent among Warao indigenous. 相似文献
70.