全文获取类型
收费全文 | 1787篇 |
免费 | 159篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 60篇 |
妇产科学 | 18篇 |
基础医学 | 236篇 |
口腔科学 | 48篇 |
临床医学 | 232篇 |
内科学 | 407篇 |
皮肤病学 | 37篇 |
神经病学 | 115篇 |
特种医学 | 171篇 |
外科学 | 241篇 |
综合类 | 39篇 |
一般理论 | 2篇 |
预防医学 | 145篇 |
眼科学 | 10篇 |
药学 | 77篇 |
1篇 | |
肿瘤学 | 105篇 |
出版年
2022年 | 17篇 |
2021年 | 22篇 |
2020年 | 23篇 |
2019年 | 30篇 |
2018年 | 37篇 |
2017年 | 19篇 |
2016年 | 30篇 |
2015年 | 45篇 |
2014年 | 46篇 |
2013年 | 70篇 |
2012年 | 60篇 |
2011年 | 66篇 |
2010年 | 60篇 |
2009年 | 52篇 |
2008年 | 61篇 |
2007年 | 88篇 |
2006年 | 80篇 |
2005年 | 77篇 |
2004年 | 64篇 |
2003年 | 58篇 |
2002年 | 70篇 |
2001年 | 49篇 |
2000年 | 41篇 |
1999年 | 43篇 |
1998年 | 48篇 |
1997年 | 62篇 |
1996年 | 55篇 |
1995年 | 28篇 |
1994年 | 40篇 |
1993年 | 30篇 |
1992年 | 37篇 |
1991年 | 38篇 |
1990年 | 25篇 |
1989年 | 44篇 |
1988年 | 42篇 |
1987年 | 26篇 |
1986年 | 23篇 |
1985年 | 24篇 |
1984年 | 25篇 |
1983年 | 21篇 |
1982年 | 19篇 |
1981年 | 15篇 |
1980年 | 12篇 |
1979年 | 10篇 |
1978年 | 14篇 |
1976年 | 11篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1972年 | 8篇 |
1969年 | 7篇 |
排序方式: 共有1952条查询结果,搜索用时 15 毫秒
11.
MP Costi D Tondi M Rinaldi D Barlocco G Cignarella DV Santi C Musiu I Pudu G Vacca P La Colla 《European journal of medicinal chemistry》1996,31(12):1011-1016
A new series of N-(substituted)benzyl-1,8-naphthalimides 4, structurally related to the previously reported thymidylate synthase (TS) inhibitor naphthaleins 3, were synthesized and compounds tested for their inhibition of several species of TS. Moreover, their in vitro cytotoxicity together with antimycotic and antibacterial properties were assayed. While no activity was detected in the antibacterial tests, the m-nitro (4ae) and the p-nitro (4af) derivatives were found able to partially inhibit TS at low micromolar concentrations. Introduction of nitro or (substituted)-amino groups in position 4 of the naphthalic ring always led to less active compounds. 相似文献
12.
13.
R Zachariah AD Harries MP Spielmann V Arendt D Nchingula R Mwenda O Courtielle P Kirpach B Mwale FML Salaniponi 《Malawi medical journal : the journal of Medical Association of Malawi》2002,14(2):10-12
In Thyolo district, Malawi, an operational research study is being conducted on the efficacy and feasibility of co-trimoxazole prophylaxis in preventing deaths in HIV-positive patients with tuberculosis (TB). A series of cross-sectional studies were carried out to determine i) whether faecal Escherichia coli (E.coli) resistance to co-trimoxazole in TB patients changed with time and ii) whether the resistance pattern was different in HIV positive TB patients who were taking co-trimoxazole prophylaxis. Co-trimoxazole resistance among E.coli isolates in TB patients at the time of registration was 60% in 1999 and 77% in 2001 (p<0.01). Resistance was 89% among HIV-infected TB patients (receiving co-trimoxazole), while in HIV negative patients (receiving anti-TB therapy alone) it was 62% (p<0.001). The study shows a significant increase of E.coli resistance to co-trimoxazole in TB patients which is particularly prominent in HIV infected patients on co-trimoxazole prophylaxis. Since a high degree of plasmid-mediated transfer of resistance exists between E.coli and the Salmonella species, these findings could herald limitations on the short and long term benefits to be anticipated from the use of co-trimoxazole prophylaxis in preventing non-typhoidal salmonella bacteraemia and enteritis in HIV infected TB patients in Malawi. 相似文献
14.
Hodgkin disease: CT of the thymus 总被引:2,自引:0,他引:2
The computed tomography (CT) scans in two groups of patients with Hodgkin disease were reviewed to determine the frequency of thymic enlargement. In 50 CT scans from 50 patients with evidence of thoracic disease on CT scans who were examined for primary staging, the thymus was enlarged in 15 of 50 (30%). Fifty CT scans were obtained from 44 patients at the time of 50 separate episodes of known or suspected relapse. Relapse occurred in the mediastinum in 12 episodes, lung parenchyma in five, and both sites in one. Thymic enlargement thought to be due to involvement by disease was present in seven of 18 (38%). Mediastinal disease was associated with thymic enlargement in all but one patient in whom a thymic cyst developed after radiation therapy. Differentiation of thymic enlargement from enlarged superior mediastinal lymph nodes was easily made in all but two patients. Thymic enlargement in the absence of lymph node enlargement may indicate a different disease, since isolated Hodgkin disease of the thymus is uncommon. Primary thymic tumor should be considered initially, whereas after treatment, rebound hyperplasia of the thymus may be the cause of enlargement. 相似文献
15.
BACKGROUND: Partnerships have been investigated in different professions,but other than identifying problems, little work has been carriedout on general practice. OBJECTIVE: The aim of this present study was to develop methods for studyingpartnerships in general practice. METHOD: A tripartite methodological approach was used, with questionnairesadapted from other instruments in use in other professions,followed by an individual interview with each partner, and non-participantobservation at a partnership meeting. Results for one case-studypartnership are given. RESULTS: There were no major differences between the partners on alldimensions measured; the minor differences indicated by theresults of the questionnaires were corroborated by the partnerinterviews and observations. CONCLUSIONS: We conclude that the use of such techniques could provide supportto partnerships going through significant periods of change. Keywords. General practice, interview, observation, partnerships, questionnaire. 相似文献
16.
17.
Abdominal trauma: use of oral contrast material for CT is safe 总被引:2,自引:0,他引:2
18.
M W Rouse P DeLand R Christian J Hawley 《Journal of the American Optometric Association》1988,59(12):946-950
A comparison study of dynamic visual acuity (DVA) was conducted using samples of nonathletic college students and college baseball players. The experimental population consisted of 17 male baseball players ranging in age from 19-24 years. The control population was made up of 25 male graduate students ranging in age from 23-29 years. Subjects reported the direction of a 20/25 "Landolt C" target exhibiting uniform angular motion produced by a projection system. Angular target velocities between 10 deg/sec and 110 deg/sec with an exposure time of 400 ms were used. The results showed a statistically significant difference between the two groups' DVA. The mean DVA for the baseball players was 82.35 deg/sec and 69.90 deg/sec for the control group. 相似文献
19.
20.
Novero V; Camus M; Tournaye H; Smitz J; Verheyen G; Joris H; Derde MP; Van Steirteghem AC; Devroey P 《Human reproduction (Oxford, England)》1997,12(1):59-63
Serum follicle stimulating hormone (FSH) is routinely measured when
evaluating the infertile male for intracytoplasmic sperm injection (ICSI).
However, among the sperm parameters, only its relationship with sperm
concentration is well documented. Few investigations concern the
relationship between FSH and sperm motility and morphology, and the results
of ICSI. A retrospective study of 316 couples who underwent ICSI was
carried out to determine the relationships between serum FSH concentrations
in the male and (i) standard sperm parameters_(concentration, motility and
morphology) and (ii) fertilization, cleavage, pregnancy and implantation
rates after ICSI. There was an inverse correlation with sperm concentration
and total motility but no relationship was found with progressive motility
and sperm morphology. Neither was any relationship found between serum FSH
and fertilization, cleavage, pregnancy and implantation rates, and the
results of ICSI. These findings suggest the need to review the routine
measurement of serum FSH in the infertile male when ICSI is the planned
treatment procedure.
相似文献