全文获取类型
收费全文 | 791篇 |
免费 | 49篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 20篇 |
妇产科学 | 7篇 |
基础医学 | 78篇 |
口腔科学 | 4篇 |
临床医学 | 66篇 |
内科学 | 162篇 |
皮肤病学 | 54篇 |
神经病学 | 37篇 |
特种医学 | 25篇 |
外科学 | 151篇 |
综合类 | 18篇 |
预防医学 | 41篇 |
眼科学 | 18篇 |
药学 | 79篇 |
中国医学 | 4篇 |
肿瘤学 | 71篇 |
出版年
2024年 | 2篇 |
2023年 | 12篇 |
2022年 | 27篇 |
2021年 | 50篇 |
2020年 | 14篇 |
2019年 | 29篇 |
2018年 | 47篇 |
2017年 | 32篇 |
2016年 | 30篇 |
2015年 | 34篇 |
2014年 | 39篇 |
2013年 | 38篇 |
2012年 | 67篇 |
2011年 | 69篇 |
2010年 | 29篇 |
2009年 | 22篇 |
2008年 | 57篇 |
2007年 | 47篇 |
2006年 | 38篇 |
2005年 | 40篇 |
2004年 | 30篇 |
2003年 | 22篇 |
2002年 | 12篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 6篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有843条查询结果,搜索用时 15 毫秒
1.
Session XII Male contraception 相似文献
2.
Thirty rhizobacteria isolated from maize grown in Pakistani and Indonesian soils were evaluated for their morphological characteristics, nitrogen fixation, P-solubilization, indole acetic acid (IAA) and siderophores production. Nitrogenase activity was detected in nineteen isolates ranging from 21.8-3624 n moles C2H4 produced/h/mg protein. Most of the isolates produced IAA, ten were capable of siderophore production while four were P-solubilizers. Ultrastructural studies of Pseudomonas sp. F14 indicated characteristic rhizospheric colonization within 48 h that was observed to change considerably with the passage of time from few bacteria to micro colonies. Random amplified polymorphic DNA (RAPD) analysis of 30 bacterial strains using 30 oligonucleotide primers resulted in considerable level of genetic diversity, with genetic distance ranging from 2-16%. Indonesian isolates were found to be more diverse as compared to Pakistani isolates. The characterization and screening of rhizobacteria of maize rhizosphere has helped in selection of isolates F7, LS-1, 3.1.1.C, F2, F3 and F13 as superior strains for use as bioinoculant. Moreover isolate F14 identified, as Pseudomonas fulgida by partial 16S rRNA sequence analysis is a novel strain regarding its tremendous potentials for inoculum production to enhance the yield of maize. 相似文献
3.
4.
Ruck NF Hafeez M Manzur S Nasir F Rivers K Prozesky D 《Journal of health & population in developing countries》1999,2(1):78-87
Pakistan's public sector is organized in a federal system with many management and planning functions devolved to the 4 provincial governments. Provincial health secretariats lead on most policy and planning decisions for health services. The provinces employ health personnel, although the national Public Service Commission controls some key aspects of human resources management. Reporting the findings of a training needs assessment (TNA) for health personnel in the provincial health services of Punjab, the authors show how TNA can be used systematically to improve the quality of health professional training. They also discuss the extent to which better training could contribute to improved health management capacity in Pakistan, and describe the context and problems of Pakistan's health services, focusing upon management capacity, and the methods and results of a training needs assessment conducted to address the problems. A final section covers the usefulness of the TNA method in Pakistan and its applicability to other countries. Moreover, the implications of decentralization and the problems of preparing training plans in the absence of decentralized structures are discussed. 相似文献
5.
Polymorphisms in interleukin -2, -6, and -10 are not associated with gastric cardia or esophageal cancer in a high-risk chinese population. 总被引:7,自引:0,他引:7
6.
7.
8.
9.
10.
Wenchao Xue Hua Li Roberto Dugnani Hafeez Ur Rehman Chunmei Zhang Yujie Chen Hezhou Liu 《RSC advances》2018,8(23):12494
In this study, a lead zirconate titanate (PZT)/in situ polymerized polyurethane (PU) composite with three-dimensional (3D) reduced graphene oxide (rGO) as the conductive phase was prepared and the potential of 3D rGO to enhance the damping properties was investigated. The conductivity and damping properties of the composite were systematically investigated. The results show that the conductive threshold of the composite is reached at a very low rGO content of about 0.7 wt% by using the 3D rGO structure. The best damping performance of the piezoelectric damping composite is achieved at the conductive threshold, where the loss factor is 0.22 (almost 41%) higher and the temperature range where tan δ ≥ 0.3 is 13.2 °C (almost 84%) wider than those of the PU matrix. A composite consisting of only PU and rGO sheets without the 3D structure was prepared for comparison. The conductive threshold of this composite is more than 0.9 wt% and the highest tensile strength is 5.63 MPa when the rGO content is 0.6 wt%, indicating that the 3D structure reduces the use of the conductive phase and does not significantly affect the tensile strength of the matrix.Piezoelectric damping composite with 3D rGO as the conductive phase that possesses good damping properties with the conductive threshold as low as 0.7 wt%. 相似文献