全文获取类型
收费全文 | 1440篇 |
免费 | 173篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 27篇 |
妇产科学 | 7篇 |
基础医学 | 198篇 |
口腔科学 | 29篇 |
临床医学 | 270篇 |
内科学 | 190篇 |
皮肤病学 | 12篇 |
神经病学 | 44篇 |
特种医学 | 61篇 |
外国民族医学 | 2篇 |
外科学 | 59篇 |
综合类 | 7篇 |
预防医学 | 110篇 |
眼科学 | 16篇 |
药学 | 531篇 |
中国医学 | 5篇 |
肿瘤学 | 44篇 |
出版年
2022年 | 12篇 |
2021年 | 12篇 |
2019年 | 9篇 |
2017年 | 11篇 |
2016年 | 12篇 |
2015年 | 27篇 |
2014年 | 14篇 |
2013年 | 22篇 |
2012年 | 33篇 |
2011年 | 37篇 |
2010年 | 19篇 |
2009年 | 37篇 |
2008年 | 64篇 |
2007年 | 75篇 |
2006年 | 52篇 |
2005年 | 60篇 |
2004年 | 52篇 |
2003年 | 52篇 |
2002年 | 69篇 |
2001年 | 85篇 |
2000年 | 77篇 |
1999年 | 75篇 |
1998年 | 29篇 |
1997年 | 22篇 |
1996年 | 27篇 |
1995年 | 21篇 |
1994年 | 28篇 |
1993年 | 23篇 |
1992年 | 49篇 |
1991年 | 52篇 |
1990年 | 40篇 |
1989年 | 45篇 |
1988年 | 46篇 |
1987年 | 49篇 |
1986年 | 30篇 |
1985年 | 26篇 |
1984年 | 31篇 |
1983年 | 21篇 |
1982年 | 19篇 |
1981年 | 15篇 |
1980年 | 13篇 |
1979年 | 9篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 12篇 |
1974年 | 12篇 |
1973年 | 11篇 |
1972年 | 7篇 |
1971年 | 10篇 |
排序方式: 共有1614条查询结果,搜索用时 0 毫秒
1.
Five 3'-fluorinated ribonucleosides were prepared and evaluated for their inhibitory properties against different viruses. The synthesis of these compounds was achieved by treatment of 2',5'-di-O-tritylated nucleoside analogues possessing a xylo-configuration with diethylaminosulfur trifluoride, followed by deprotection. 3'-Fluoro-3'-deoxyadenosine was active against a broad range of viruses, encompassing both DNA viruses [pox (vaccinia)], single-stranded (+) RNA viruses [picorna (polio, Coxsackie B), toga (sindbis, Semliki Forest)] and double-stranded RNA viruses (reo). In its antiviral activity spectrum 3'-fluoro-3'-deoxyadenosine clearly differed from those adenosine analogues that are known as inhibitors of S-adenosylhomocysteine hydrolase. 3'-Fluoro-3'-deoxyadenosine also proved effective in vivo, in inhibiting tail lesion formation in mice inoculated intravenously with vaccinia virus. 相似文献
2.
3.
Suppurative corneal ulceration in Bangladesh 总被引:8,自引:0,他引:8
AAS Dunlop MB BS ED Wright MRCPath † SA Howlader‡ I Nazrul‡ R Husain‡ K McClellan FRACO § FA Billson FRACO § 《Clinical & experimental ophthalmology》1994,22(2):105-110
Suppurative keratitis is an important preventable cause of blindness, particularly in the developing world. This study analyses 142 cases of suppurative keratitis referred to Chittagong Eye Infirmary, Bangladesh. Some 53.5% of cases were bacterial and 35.9% were fungal. The five most common pathogens were: Pseudomonas sp. 24%, Streptococcus pneumoniae 17%, Aspergillus sp. 13%, Fusarium sp. 7% and Curvularia sp. 6%. Gram stain and culture results were consistent in 62.6% of cases. Previous antibiotic treatment was a significant factor for failure of culture isolation and less so for Gram stain failure. On Gram stain, 55.9% of pseudomonal cases were missed, but only 2% of fungal cases were missed. Over all, Gram stain had a sensitivity of 62% and positive predictive value of 84% for bacterial cases, and 98% and 94% for fungal cases, respectively. Fungal ulcers were typically filamentous, but an antecedent history of trauma was not common. The most frequent injury was due to rice grains, but the inoculum appeared to be introduced during eye washing with contaminated water. Pseudomonal ulcers occurred most frequently in the monsoon season, and Fusarium cases were seen only in the hot, dry season. 相似文献
4.
5-Fluorouracil, 5-fluorouridine (FUrd), 5-fluoro-2'-deoxyuridine (FdUrd), 5-fluorocytidine (FCyd), 5-fluoro-2'-deoxycytidine (FdCyd), 5-trifluoro-2'-deoxythymidine (F3dThd), and the 5'-monophosphates and 3',5'-cyclic monophosphates thereof were found to inhibit thymidine kinase-deficient (TK-) mutant strains of herpes simplex virus (HSV) at a much lower concentration than the wild-type (TK+) HSV strains. Other 5-substituted 2'-deoxyuridines that have previously been recognized as potent thymidylate synthase inhibitors behaved in a similar fashion. The activity of FdUrd, FdCyd, F3dThd, and their 3',5'-cyclic monophosphates against TK-HSV was readily reversed by 2'-deoxythymidine (dThd) but not by 2'-deoxyuridine (dUrd). These compounds also inhibited the incorporation of [6-3H]dUrd into DNA at a concentration which was up to 5 orders of magnitude lower than the concentration at which the incorporation of [methyl-3H] dThd was inhibited. Thus, while not being a target for the well established anti-HSV compounds in TK+HSV-infected cells, thymidylate synthase appears to be an important target in TK-HSV-infected cells. In addition to dTMP synthase, TK-HSV-infected cells appear to reveal other therapeutically exploitable targets such as OMP decarboxylase (towards pyrazofurin), CTP synthase (towards carbodine and its cyclopentenyl analogue), dihydrofolate reductase (towards methotrexate), and S-adenosylhomocysteine hydrolase (towards neplanocins). 相似文献
5.
6.
7.
. We invited Dr Peplau to provide a personal reflection on the recent history of psychiatric nursing and her thoughts on immediate challenges facing the profession. The paper is an individual scholar's commentary on the way that psychiatry has waxed and waned over the years, in relation to nursing. This historical review discovers and reports a challenge to current practice. Dr Peplau describes a professional shift that is pulling nurses toward the subordinate role observed earlier this century. The paper draws attention to how contemporary practice can be positively influenced, e.g., by giving a structure to the allocation and conduct of nurse–patient time. 相似文献
8.
Intracellular metabolism and mechanism of anti-retrovirus action of 9-(2-phosphonylmethoxyethyl)adenine, a potent anti-human immunodeficiency virus compound. 总被引:11,自引:0,他引:11
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
9.
Depending on the cell line used for virus propagation, human immunodeficiency virus (HIV) particles may possess class II MHC proteins, as demonstrated by FACS analysis. HLA-DR appeared in high amounts at the HIV envelope, if the virus was grown in HLA-DR+ cells, but was absent if the virus had been grown in HLA-DR- cells. No other cellular constituents, including HLA-DQ and HLA-DP, were detected in these virions. The presence of HLA-DR in the virion envelope itself in preparations used for diagnostic purposes may explain some of the false-positive results obtained in earlier serological tests for HIV infection. Possible implications of these virus-associated cellular antigens in the immunopathogenesis of AIDS should be considered. 相似文献
10.
A study on the psychiatric confinements in the Walloon region in the year 1984 allows to define the patient's psychopathology and the context of the requests. The new law of the 26 June 1990 relating to the protection of the mentally ill person will probably be used mostly in such situations. Its conditions of implementation, positive aspects and the difficulties it could create are detailed. 相似文献