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   3365篇
  免费   181篇
  国内免费   32篇
耳鼻咽喉   28篇
儿科学   100篇
妇产科学   69篇
基础医学   370篇
口腔科学   59篇
临床医学   359篇
内科学   867篇
皮肤病学   59篇
神经病学   346篇
特种医学   203篇
外科学   342篇
综合类   25篇
一般理论   2篇
预防医学   165篇
眼科学   47篇
药学   196篇
中国医学   12篇
肿瘤学   329篇
  2023年   21篇
  2022年   22篇
  2021年   52篇
  2020年   38篇
  2019年   50篇
  2018年   74篇
  2017年   59篇
  2016年   66篇
  2015年   56篇
  2014年   86篇
  2013年   125篇
  2012年   168篇
  2011年   177篇
  2010年   88篇
  2009年   102篇
  2008年   175篇
  2007年   187篇
  2006年   179篇
  2005年   142篇
  2004年   125篇
  2003年   127篇
  2002年   115篇
  2001年   116篇
  2000年   115篇
  1999年   96篇
  1998年   67篇
  1997年   56篇
  1996年   53篇
  1995年   46篇
  1994年   50篇
  1993年   34篇
  1992年   53篇
  1991年   58篇
  1990年   54篇
  1989年   62篇
  1988年   85篇
  1987年   51篇
  1986年   46篇
  1985年   36篇
  1984年   33篇
  1983年   21篇
  1982年   19篇
  1981年   12篇
  1980年   16篇
  1979年   31篇
  1978年   14篇
  1977年   17篇
  1976年   10篇
  1974年   11篇
  1969年   14篇
排序方式: 共有3578条查询结果,搜索用时 15 毫秒
1.
2.
The treatment for chronic hepatitis C with interferon and ribavirin is associated with a large number of untoward side effects ( Cornberg, Wedemeyer &, Manns, 2002). Management of these adverse effects has a great impact on the compliance of affected patients during the course of their treatment. Thus, the influence of the nurse on patient compliance and quality of life improvement during interferon and ribavirin treatment cannot be understated. Anecdotally, from the patient's point of view, the adverse effects of treatment often overshadow the goal of treatment, viral clearance. Nurses, as a result of their role as patient advocates, have the ability to enhance treatment compliance greatly by recognizing and managing treatment-associated side effects.  相似文献   
3.
Lycopene, a non-provitaminic carotenoid, present in many fruit and vegetables, such as tomatoes and their processed products, has been associated with decreased risk of chronic diseases including cancer. The influence of lycopene on the proliferation of the breast tumour cell line (MCF-7) was tested using MTT and BrdU assays at different time intervals (from 24 to 72h) and dose-response (from 0.125 to 100muM). The induction of Gap Junction Intercellular Communication (GJIC) was evaluated by dye-transfer assay using Lucifer Yellow on monolayer cells treated with different lycopene concentrations (from 0.125 to 5muM) for 6 to 48h. The Minimal Inhibitory Concentration (MIC) of lycopene was of 5muM, after a 24h exposure. A prolonged exposure time (72h) induced a similar inhibitory effect. Lycopene stimulated the functionality of GJIC at concentrations of 1muM after 24h and this effect was dose-dependent. The induction of GJIC by lycopene was confirmed by an increased expression of connexin 43. Collectively, the above data confirm the inhibitor effects of lycopene on MCF-7 cell growth and suggest that lycopene is involved in the modulation of the gap junction intercellular communication in this cell line, as observed for other cancer cell lines.  相似文献   
4.
Abstract: Research indicates that two major forms of partner violence exist, intimate terrorism (IT) and situational couple violence (SCV). The current study (N= 389) used a subgroup of women who responded to the Chicago Women’s Health Risk Study to examine whether type of violence experienced is differentially related to formal (e.g., police, medical agencies, counseling) and informal (e.g., family, friends/neighbors) help seeking. IT victims were more likely to seek each type of formal help but were equally or less likely to seek informal help. Findings can inform both family violence research and the development and implementation of social service programs.  相似文献   
5.
A 38-year-old man presented with hyperophthalmia, enophthalmos, and upper eyelid retraction 18 months following an osteoplastic flap and frontal sinus obliteration for mucocele. Computerized tomography confirmed the presence of frontal bone absorption in the roof of the orbit with traction and elevation of the orbital contents into the obliterated frontal sinus. A fracture of the orbital roof with penetration of periorbita at the time of original surgery was the suspected precipitating cause of the complication. Surgical management included lysis of the cicatrix between the orbit and frontal sinus and interposition of a silicone sheet between the orbit and sinus, which restored the appropriate anatomic relationships and prevented recurrence.  相似文献   
6.
The chain propagation rate constants for the polymerization of ethylene and propene in the presence of δ-TiCl3/Al(CH3)3 at 22 °C are determined by means of a 13C NMR analysis of suitable block copolymers. The numerical values of the rate constants are compared with those previously reported.  相似文献   
7.
Chitambar  CR; Zivkovic  Z 《Blood》1989,74(2):602-608
Information regarding transferrin (Tf) receptor degradation is largely incomplete. HL60 cells were shown to release to their growth medium a Tf-binding protein which could be immunoprecipitated by anti-Tf receptor monoclonal antibodies (MoAbs) B3/25 and OKT9. Soluble Tf receptor was detected in the medium within one hour of replating of cells, and its release was inhibited at 4 degrees C. The affinity of Tf for the soluble receptor released by cells (kd = 2.3 x 10(-10) mol/L) was slightly lower than its affinity for the detergent-solubilized cellular receptor (kd = 1.2 x 10(-10) mol/L). 125I-Tf internalized and released by cells subsequently bound to Tf receptor released by the same cells, and soluble Tf receptor in the conditioned medium (CM) inhibited 125I-Tf binding to intact cells. The soluble Tf receptor isolated from the CM was smaller (78,000 daltons) than the cell surface receptor (94,000 daltons) when analyzed by gel electrophoresis under reducing conditions. Isolated cell membranes readily released soluble receptor; however, this release could be blocked by protease inhibitors. The soluble Tf receptor may represent the extracytoplasmic domain of the cellular Tf receptor released from the surface of HL60 cells through proteolytic cleavage by a membrane-based protease.  相似文献   
8.
9.
The purpose of this study was threefold: to evaluate the role of gallium-67 scintigraphy in the staging of low-grade non-Hodgkin’s lymphomas (LGNHL), to assess the relationship between the expression of CD71 on the surface of the neoplastic cells and the 67Ga uptake by the tumour, and to establish the contribution of 67Ga scan in defining the prognosis of LGNHL. Forty-eight patients with untreated LGNHL diagnosed in a single institution over a decade were reviewed. The end point of the study was survival of the patients according to the scintigraphic 67Ga score at diagnosis. In addition to 67Ga scan, other prognostic variables were studied, relating to the neoplastic burden, the biology of the tumour and the host. Univariate and multivariate analyses were used. 67Ga scan identified only 116/286 (41%) nodes involved by lymphoma that were detected by clinical examination or computed tomography scan. A scintigraphic scoring system with an arbitrary cut-off value of 3 (high scan score) was able to predict patients with a dismal prognosis: with a mean follow-up of 47 months (range: 1–146 months) the median survival time was 28 months in patients with a high scan score and 74 months in patients with a low scan score (P=0.002). CD71 values were 27.4%±14.9% (mean ±SD) in the former and 8.9%±7.2% in the latter (P=0.0001). Only performance status and extranodal sites were significant variables for prognosis in multivariate analysis. It is concluded that 67Ga scan is inaccurate in staging but might be very important in defining the prognosis in LGNHL, in association with other prognostic variables. Received 1 May and in revised form 6 August 1997  相似文献   
10.
BACKGROUND: Identify risk factors for asthma in adolescents from S?o Paulo, Brazil. METHODS: total of 528 adolescents (141 asthmatics, 387 control subjects) from the ISAAC study (phase III) were submitted to a complementary questionnaire to evaluate risk factors, through response to questions regarding personal history, environment, and diet and an agreement to undergo the skin prick test (SPT) for aeroallergens. RESULTS: Positive SPT to at least one allergen occurred in 49.4% adolescents. The risk factors for asthma were: prematurity (OR: 3.84, 95% CI: 1.54-9.64), rhinitis (OR: 3.18, 95% CI: 1.71-5.91), positivity in the SPT (OR: 2.81, 95% CI: 1.48-5.32), eczema in characteristic skin-folds (OR: 2.86, 95% CI: 1.13-7.26), and an allergic mother (OR: 2.01, 95% CI: 1.02-3.93). The consumption of cooked vegetables was a protective factor for asthma (OR: 0.37, 95% CI: 0.18-0.79) CONCLUSIONS: Asthma is a multifatorial disease. An allergic mother, aeroallergen sensitization, rhinitis, eczema and prematurity were considered risk factors and the consumption of cooked vegetables was considered a protective factor for asthma in this population.  相似文献   
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