首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   456篇
  免费   52篇
  国内免费   3篇
耳鼻咽喉   4篇
儿科学   19篇
妇产科学   9篇
基础医学   57篇
口腔科学   7篇
临床医学   54篇
内科学   134篇
皮肤病学   5篇
神经病学   46篇
特种医学   11篇
外科学   42篇
综合类   4篇
预防医学   35篇
眼科学   5篇
药学   57篇
中国医学   4篇
肿瘤学   18篇
  2023年   2篇
  2022年   12篇
  2021年   14篇
  2020年   16篇
  2019年   19篇
  2018年   22篇
  2017年   24篇
  2016年   18篇
  2015年   24篇
  2014年   17篇
  2013年   26篇
  2012年   52篇
  2011年   38篇
  2010年   19篇
  2009年   17篇
  2008年   28篇
  2007年   12篇
  2006年   18篇
  2005年   24篇
  2004年   15篇
  2003年   14篇
  2002年   11篇
  2001年   11篇
  2000年   8篇
  1999年   6篇
  1998年   2篇
  1997年   1篇
  1996年   2篇
  1995年   5篇
  1994年   3篇
  1993年   6篇
  1992年   5篇
  1991年   6篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1987年   2篇
  1985年   1篇
  1979年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1973年   2篇
  1971年   1篇
排序方式: 共有511条查询结果,搜索用时 15 毫秒
51.
Pool R  Kamali A  Whitworth JA 《AIDS care》2006,18(5):479-488
Studies report substantial sexual behaviour change in Africa in response to HIV/AIDS. Generally there seems to be an increase in condom use and a reduction in partners, with men reporting more change than women. However, it is not only important to know whether people are changing their sexual behaviour but also their reasons for changing and the consistency and extent of change. Between 1996 and 2000 a study involving 196 respondents was carried out in rural southwest Uganda to investigate the exact nature of behaviour change and the reasons for change or lack of change since people became aware of HIV/AIDS. Data were collected from three rounds of questionnaire surveys, four rounds of open in-depth interviews, six rounds of semi-structured interviews and from informal conversations and participant observation. In order to obtain a comprehensive assessment of behaviour change the data for each participant from all sources were compared and discrepancies were then followed up by re-interviewing participants. After triangulation between all sources of data, 48% of respondents had ever used a condom. Condom use in 76% of all cases was at least partly AIDS related, while 19% was exclusively for protection against HIV. Condom use tended to be sporadic: only 13% of condom users currently used a condom regularly and most of this use was for family planning. After triangulation, 45% had reduced the number of sexual partners. Of all partner reductions, 93% was at least partly AIDS related; 29% was exclusively to avoid HIV. Half of those who had reduced the number of partners either stuck to one partner or abstained. Men reported more change than women. Of those who reported no partner reduction, 89% could not reduce the number of partners because they already had only few or a single partner or abstained; most of these were women. Most of those who could change their sexual behaviour had already changed, though the degree of change (particularly condom use) was often minimal. Not only behaviour change, but also the maintenance of safe behaviour is important. Also, understanding reasons for change and extent and consistency of change are important when planning and evaluating interventions.  相似文献   
52.
In recent years, great attention has been paid to using solid dispersions to make sustained-release drugs. The objective of this study is to produce sustained-release systems of metoprolol tartrate using solid dispersion techniques and to evaluate their physicochemical characteristics. The solid dispersions were produced by melting and solvent methods, containing 7%, 15%, or 25% of the drug and different ratios of Eudragit RLPO and RSPO in ratios of 0:10, 3:7, 5:5, 7:3, and 10:0. Drug release profiles were determined by USP XXIII rotating paddle method in phosphate buffer solution (pH 6.8). XRD, DSC, IR, and microscopic observations were performed to evaluate the physical characteristics of solid dispersions. Results showed that the drug release from dispersions was at a slower rate than pure drug and physical mixtures. Moreover, the formulations containing greater ratios of Eudragit RSPO showed slower release rates and smaller DE8% but larger mean dissolution time than those containing greater ratios of Eudragit RLPO. Dispersions with particle size of less than 100 μm containing 7% of metoprolol and Eudragit RL:RS 5:5 (solvent method) and those with the ratio of 3:7 (melting method) had similar release pattern to Lopressor® sustained-release tablets by zero-order and Higuchi kinetics, respectively.  相似文献   
53.
54.
As the search for an effective human malaria vaccine continues, understanding immune responses to Plasmodium in rodent models is perhaps the key to unlocking new vaccine strategies. The recruitment of parasite-specific antibodies is an important component of natural immunity against infection in blood-stage malaria. Here, we describe the use of sera from naturally surviving ICR mice after infection with lethal doses of Plasmodium yoelii yoelii 17XL to identify highly immunogenic blood-stage antigens. Immobilized protein A/G was used for the affinity-chromatography purification of the IgGs present in pooled sera from surviving mice. These protective IgGs, covalently immobilized on agarose columns, were then used to isolate reactive antigens from whole P. yoelii yoelii 17XL protein extracts obtained from the blood-stage malaria infection. Through proteomics analysis of the recovered parasite antigens, we were able to identify two endoplasmic reticulum lumen proteins: protein disulfide isomerase and a member of the heat shock protein 70 family. Also identified were the digestive protease plasmepsin and the 39 kDa-subunit of eukaryotic translation initiation factor 3, a ribosome associated protein. Of these four proteins, three have not been previously identified as antigenic during blood-stage malaria infection. This procedure of isolating and identifying parasite antigens using serum IgGs from malaria-protected individuals could be a novel strategy for the development of multi-antigen-based vaccine therapies.  相似文献   
55.
This report presents the results of the first faunistic study of hard ticks in Qazvin province of Iran. The primary objective was to determine the species diversity and geographic distribution of hard ticks that parasitize domestic ruminants. Information about the abiotic preferences of these species has been provided. A total of 286 cattle, 1,053 goats, and 2,050 sheep were examined in 13 villages in 28 flocks distributed throughout the studied areas. Total direct body collections of ticks were made from each domestic ruminant. A total of 228 Ixodid specimens belonging to nine species in three different genera were recorded in the areas, including Boophilus annulatus (Say, 1821), Hyalomma anatolicum Koch, 1844, Hyalomma asiaticum (Schulze and Schlettke, 1929), Hyalomma detritum Schulze, 1919, Hyalomma dromedarii Koch, 1844, Hyalomma marginatum Koch 1844, Hyalomma schulzei Olenev, 1931, Rhipicephalus bursa Canestrini and Fanz, 1878 and Rhipicephalus sanguineus (Latreille, 1806). The most abundant species on sheep was R. sanguineus (46.92%), while B. annulatus (6.6%) found only on cattle. A finding of great significance was that R. sanguineus, the main vector of babesiosis, is firmly established throughout the counties. A further objective of the study was to compare the abundance of the major tick species on domestic ruminants. This was carried out at 19 sampling sites. The highest number of ticks was collected in July–August during the hot season.  相似文献   
56.
Tumour necrosis factor-alpha (TNF-α) antagonist drugs have been associated with increased risk of tuberculosis (TB). Tuberculin skin test (TST) is the most frequently used tool for identification of latent TB infection. We herein aimed to analyse the effect of TNF-α antagonists on the TST responses in a prospective study. The study group consisted of 182 patients (99 female, 83 male) who received TNF-α antagonists for various rheumatic disorders. All patients were evaluated with TST along with other parameters on the day of referral and on the 12th month visit. For those patients with a response of <5 mm induration at the initial evaluation, the TST was repeated to observe the booster effect. Out of 182 patients, 87 patients (48%) had a negative (0–4 mm) and 95 (52%) had a positive (≥5 mm) TST response at initial evaluation. The TST responses were converted from negative at initial visit to positive at 1-year repeat in 26 (30%) patients. A significant increase was observed in the diameters of TST that were repeated on the first year of TNF-α antagonist treatment (9.15 ± 0.55) compared to their initial diameters (6.60 ± 0.51) (P < 0.001). Increased TST responses in patients receiving TNF-α antagonists may be associated with the restoration of suppressed immune reactivity against TB antigens with the decreased disease activity. The meaning of TST conversion in the definition of latent TB infection and the need for chemoprophylaxis in these patients remains to be answered by further studies.  相似文献   
57.
58.
Ryan KA, Vederman AC, McFadden EM, Weldon AL, Kamali M, Langenecker SA, McInnis MG. Differential executive functioning performance by phase of bipolar disorder. Bipolar Disord 2012: 14: 527–536. © 2012 The Authors. Journal compilation © 2012 John Wiley & Sons A/S. Objective: This study examined the influence of illness phase on executive functioning performance using factor‐derived cognitive scores in a cross‐sectional design. Methods: Healthy control (HC) subjects (n = 57), and euthymic (E‐BD) (n = 117), depressed (D‐BD) (n = 73), and hypomanic/mixed (HM/M‐BD) (n = 26) patients with bipolar disorder (BD) were evaluated using executive functioning measures (Wisconsin Card Sorting Test, Trail Making Test–Parts A and B, Verbal Fluency, Parametric Go/No‐Go, Stroop, and Digit Symbol) comprising Conceptual Reasoning and Set‐Shifting (CRSS), Processing Speed with Interference Resolution (PSIR), Verbal Fluency and Processing Speed (VFPS), and Inhibitory Control (IC) factor scores. Results: Two of the four executive functioning factors were significantly different between groups based upon phase of illness. The HM/M group was significantly worse than both of the other BD groups and the HC group in IC. The VFPS factor was sensitive to the active phase of BD, with the HM/M‐BD and D‐BD groups worse than HC. Extending our prior work, the PSIR factor, and now the CRSS factor were significantly worse in BD relative to HC, irrespective of phase of illness. Conclusions: Phase of illness had differential cognitive profiles in executive functioning factors, even after considering and excluding the impact of clinical features, illness characteristics, medications, and demographics. Consolidating executive functioning tasks into reliable factor scores provides unique information to measure and define cognitive deficiencies throughout phases of BD, and to measure intermediate phenotypes in BD, and may aid in tracking and clarifying treatment focus.  相似文献   
59.
Dirofilariasis is a zoonotic global vector‐borne disease caused by Dirofilaria immitis. The present study focuses on the somatic and excretory/secretory (E/S) proteins released from adult D. immitis. We aimed to fractionate and identify adult D. immitis immunoreactive proteins. Somatic and E/S extracts were immunoblotted to identify the immunoreactive proteins. In the current study, we used matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐TOF/MS) to characterize the immunogenic proteins. Additionally, we used fast protein liquid chromatography (FPLC) to fractionate and evaluate the immunogenicity of the D. immitis secretome. The most immunoreactive proteins were between 10 and 48 kDa. Six proteins including polyprotein antigen, P22u, pepsin inhibitor Dit33, neutrophil chemotactic factor (DiNCF) precursor, glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) and heat‐shock protein 70 (HSP70) were found in both somatic and E/S extracts. Eluting the FPLC column with NaCl resolved two peaks in which the immunoreactivities of the purified proteins were conserved. Characterization of these proteins could provide a novel perspective for understanding the pathogenesis and diagnosing of this disease.  相似文献   
60.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号