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   6187篇
  免费   492篇
  国内免费   10篇
耳鼻咽喉   59篇
儿科学   223篇
妇产科学   147篇
基础医学   857篇
口腔科学   60篇
临床医学   711篇
内科学   1085篇
皮肤病学   162篇
神经病学   674篇
特种医学   126篇
外科学   754篇
综合类   44篇
一般理论   2篇
预防医学   818篇
眼科学   87篇
药学   433篇
中国医学   2篇
肿瘤学   445篇
  2024年   5篇
  2023年   72篇
  2022年   126篇
  2021年   260篇
  2020年   178篇
  2019年   230篇
  2018年   288篇
  2017年   209篇
  2016年   194篇
  2015年   245篇
  2014年   308篇
  2013年   412篇
  2012年   575篇
  2011年   507篇
  2010年   285篇
  2009年   242篇
  2008年   346篇
  2007年   340篇
  2006年   333篇
  2005年   320篇
  2004年   275篇
  2003年   265篇
  2002年   225篇
  2001年   32篇
  2000年   35篇
  1999年   31篇
  1998年   48篇
  1997年   27篇
  1996年   22篇
  1995年   16篇
  1994年   17篇
  1993年   17篇
  1992年   17篇
  1991年   18篇
  1990年   15篇
  1989年   15篇
  1988年   11篇
  1987年   13篇
  1986年   11篇
  1985年   9篇
  1984年   5篇
  1983年   9篇
  1981年   7篇
  1980年   5篇
  1979年   9篇
  1978年   5篇
  1976年   6篇
  1975年   10篇
  1973年   6篇
  1968年   4篇
排序方式: 共有6689条查询结果,搜索用时 31 毫秒
51.
The management of choledocholithiasis in children and teenagers is often a two-procedure process with laparoscopic cholecystectomy (LC) and either pre- or post-operative endoscopic retrograde cholangiopancreatography (ERCP). The addition of laparoscopic common bile duct exploration (LCBDE) during LC can provide definitive treatment for choledocholithiasis during a single anesthetic event. In an effort to minimize sedation and radiation exposure from fluoroscopy, we have employed dilating balloons via a transcystic approach to stretch the sphincter of Oddi with subsequent ductal flushing. We describe the technique of balloon sphincteroplasty as a straightforward adjunct within the pediatric surgeon's skill set to manage choledocholithiasis during LC and our clinical experience.  相似文献   
52.
Radiation-induced breast angiosarcoma, or secondary angiosarcoma (SAS), is a rare entity with a high risk of metastatic recurrence. Herein, we describe the use of intraoperative fluorescence-based skin angiography to guide surgical resection following a novel immunotherapy-based regimen for SAS resulting in a complete pathological response.  相似文献   
53.
54.

Sexual consent can be conceptualized as a process of accumulating cues that build toward and continue throughout a consensual sexual encounter. How people perceive the cues of others during this process is an important aspect of consent. However, previous research has not investigated the trajectories of people’s consent perceptions throughout such a process. Using a novel staggered vignette protocol, we examined participants’ (N?=?1218; 64.4% female) perceptions of fictional targets’ sexual consent at 11 time points. We tested latent growth curve models using multilevel structural equation modeling to examine trajectories in consent perceptions over the course of the vignette. We hypothesized that mean differences and rates of change would be associated with several constructs relevant to sexual consent. We found that initial consent perceptions and trends over the course of the vignette varied by whether the participant was a university student, by an alcohol manipulation in the vignette, by the fictional target’s sex, and by type of sexual behavior. Researchers should examine whether our findings on consent perceptions of a fictional vignette extend to people’s actual sexual encounters, including potential associations between the three primary aspects of sexual consent: perceptions, feelings, and communication.

  相似文献   
55.
56.
Growing interest surrounds adoptive cellular therapies utilizing Natural Killer (NK) cells, which can be obtained from various sources, including umbilical cord blood (UCB) and adult peripheral blood (APB). Understanding NK cell receptor expression and diversity in such cellular sources will guide future therapeutic designs. We used a 20-color flow cytometry panel to compare unstimulated and cytokine-activated UCB and APB NK cells. Our analysis showed that UCB NK cells express slightly higher levels of the immune checkpoints PD-1, TIGIT, and CD96 compared to their APB counterparts. Unsupervised hierarchical clustering and dimensionality reduction analyses revealed enrichment in CD56neg as well as mature NKp46neg and CD56+CD16+ NK cell populations in UCB whereas CD57+ terminally differentiated NK cells with variable expression of KIRs and CD16 were found in APB. These populations were conserved following stimulation with IL-12, IL-15, and IL-18. Cytokine stimulation was associated with the downregulation of TIGIT and CD16 on multiple NK cell subsets in UCB and APB. Among UCB CD16 NK cell populations, TIGIT+ NK cells produced more IFN-γ than their TIGIT counterparts. Our data demonstrate higher immune checkpoint expression on UCB NK cells compared to APB. However, the expression of TIGIT immune checkpoint is not indicative of NK cell exhaustion.  相似文献   
57.
The effect of a standard regimen of the investigational macrolide antibiotic, dirithromycin, on the single-dose kinetics of orally administered cyclosporine (CSA) was investigated in healthy young males and on the steady-state disposition kinetics of cyclosporine in a panel of renal transplant patients. Eight male volunteers participated after giving informed consent. CSA was administered in three single doses (15 mg kg(minus sign1) p.o. each) in each of three phases: (1) prior to a 14-day regimen of dirithromycin; (2) at the end of a 14-day regimen of dirithromycin (500 mg p.o. qAM); and (3) 2 weeks after the last dose of a 14-day regimen of dirithromycin. Pharmacokinetic parameters of CSA were estimated, and the differences among treatments were assessed by analysis of variation. No significant differences among treatment (phase) means were detected (p < 0.05). We conclude that a typical 14-day regimen of dirithromycin failed to alter the disposition kinetics of CSA when taken orally healthy young adult males. The effect of a standard regimen of dirithromycin on the steady-state disposition kinetics of orally administered CSA was investigated in a panel of 15 stable renal transplant patients. Pharmacokinetic parameters for CSA were evaluated prior to, during, and 2 weeks after discontinuing a 14-day (500 mg day(minus sign1)) oral regimen of dirithromycin. Dirithromycin elicited small but significant changes in the following parameters: C(av) was increased by 16% during dirithromycin treatment, and the changes in normalized C(av) were comparable. Likewise, C(SS,min) and normalized C(SS,min) were increased by 19% and 20%, respectively, during dirithromycin treatment. CSA oral clearance, CL/F(SS), decreased by 17% during dirithromycin treatment. C(SS,max) and normalized C(SS,max) were increased by 13% and 17%, respectively, during dirithromycin treatment but were not significantly different from those either before or after dirithromycin. The magnitude of the pharmacokinetic changes for CSA during dirithromycin treatment (<15% in normal subjects and 15--20% in renal transplant patients) when considered in the context of the therapeutic range of cyclosporine concentrations was relatively small, and not likely to warrant special attention to the dosing of CSA in such patients beyond routine whole-blood CSA and serum creatinine monitoring.  相似文献   
58.
This study explores three issues: thoughts and feelings of individuals with and without physical disabilities concerning encounters in different situations, ways of grouping self-statements into valenced categories, and use of states-of-mind (SOM) ratios as an alternative to positive and negative thought frequencies. Data from 127 able-bodied and 46 physically disabled college students indicate that, in everyday social encounters, nondisabled individuals' thoughts and feelings were more negative, while those of disabled individuals were more negative when helping was involved and when encounters centered on the impairment. Thus, problematic encounters between people with and without disabilities may be due to the reactions of individuals with disabilities in situations which involve help, and to reactions of able-bodied persons in everyday contexts. The data also confirm the utility of SOM ratios as an alternative to valenced frequencies in cognitive assessment: SOM scores discriminated groups when situational demands were manipulated and scores were linearly related to criterion measures. However, SOM ratios differed dramatically, depending on the attentional focus of thoughts. The findings illustrate types of thoughts which occur during interaction between people with and without disabilities, demonstrate a simple technique for grouping thoughts into valenced categories on an empirical basis, and highlight the relative contribution of cognitive and affective elements to overall valenced scores. Implications for research on assessment of self-statements are discussed and recommendations are made concerning programming to facilitate the social integration of people with disabilities.This research was supported by grants to the first author from the Social Sciences and Humanities Research Council of Canada and from Fonds F.C.A.R. pour l'aide et le soutien à la recherche. Thanks are due to Meribah Aikens, Maria Barile, Leo Bissonette, Bosco Daude, Jim Dubois, Lillian Fox, Evelyn Gold, Naomi Goodz, Darlene Judd, André Leblanc, John Martos, Sue McKenzie, Irwin Slopak, and Joan Wolforth for their assistance with various stages of this investigation.  相似文献   
59.
60.
A vitamin E derivative, vitamin E succinate (VES; RRR-alpha-tocopheryl succinate), and a vitamin E analogue, 2,5,7,8-tetramethyl-2R-(4R,8R,12-trimethyltridecyl)chroman-6-yloxy acetic acid (alpha-TEA), induce human breast, prostate, colon, lung, cervical, and endometrial tumor cells in culture to undergo apoptosis but not normal human mammary epithelial cells, immortalized, nontumorigenic breast cells, or normal human prostate epithelial cells. Human ovarian and cervical cancer cell lines are exceptions, with alpha-TEA exhibiting greater proapoptotic effects. Although both VES and alpha-TEA can induce A2780 and subline A2780/cp70 ovarian cancer cells to undergo DNA synthesis arrest within 24 h of treatment, only alpha-TEA is an effective inducer of apoptosis. VES or alpha-TEA treatment of cp70 cells with 5, 10, or 20 microg/ml for 3 days induced 5, 6, and 19% versus 9, 36, and 71% apoptosis, respectively. Colony formation data provide additional evidence that cp70 cells are more sensitive to growth inhibition by alpha-TEA than VES. Differences in stability of the ester-linked succinate moiety of VES versus the ether-linked acetic acid moiety of alpha-TEA were demonstrated by high-performance liquid chromatography analyses that showed alpha-TEA to remain intact, whereas VES was hydrolyzed to the free phenol, RRR-alpha-tocopherol. Pretreatment of cp70 cells with bis-(p-nitrophenyl) phosphate, an esterase inhibitor, before VES treatment, resulted in increased levels of intact VES and apoptosis. Taken together, these data show alpha-TEA to be a potent and stable proapoptotic agent for human ovarian tumor cells and suggest that endogenous ovarian esterases can hydrolyze the succinate moiety of VES, yielding RRR-alpha-tocopherol, an ineffective apoptotic-inducing agent.  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