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   2387篇
  免费   128篇
  国内免费   18篇
耳鼻咽喉   4篇
儿科学   61篇
妇产科学   51篇
基础医学   315篇
口腔科学   16篇
临床医学   155篇
内科学   739篇
皮肤病学   21篇
神经病学   109篇
特种医学   114篇
外国民族医学   1篇
外科学   248篇
综合类   117篇
一般理论   1篇
预防医学   198篇
眼科学   138篇
药学   110篇
中国医学   1篇
肿瘤学   134篇
  2021年   25篇
  2019年   28篇
  2018年   39篇
  2017年   25篇
  2016年   33篇
  2015年   29篇
  2014年   37篇
  2013年   49篇
  2012年   84篇
  2011年   91篇
  2010年   52篇
  2009年   58篇
  2008年   99篇
  2007年   123篇
  2006年   114篇
  2005年   101篇
  2004年   115篇
  2003年   101篇
  2002年   84篇
  2001年   74篇
  2000年   65篇
  1999年   59篇
  1998年   54篇
  1997年   35篇
  1996年   32篇
  1995年   23篇
  1994年   28篇
  1993年   21篇
  1992年   54篇
  1991年   49篇
  1990年   39篇
  1989年   49篇
  1988年   56篇
  1987年   37篇
  1986年   37篇
  1985年   31篇
  1984年   18篇
  1983年   29篇
  1982年   18篇
  1981年   23篇
  1980年   22篇
  1979年   19篇
  1977年   19篇
  1975年   16篇
  1973年   14篇
  1972年   15篇
  1971年   15篇
  1970年   14篇
  1969年   12篇
  1924年   12篇
排序方式: 共有2533条查询结果,搜索用时 0 毫秒
991.
We conducted a 9-cM genome scan in a large bipolar pedigree sample from the National Institute of Mental Health genetics initiative (1060 individuals from 154 multiplex families). We performed parametric and nonparametric analyses using both standard diagnostic models and comorbid conditions thought to identify phenotypic subtypes: psychosis, suicidal behavior, and panic disorder. Our strongest linkage signals (genome-wide significance) were observed on chromosomes 10q25, 10p12, 16q24, 16p13, and 16p12 using standard diagnostic models, and on 6q25 (suicidal behavior), 7q21 (panic disorder) and 16p12 (psychosis) using phenotypic subtypes. Several other regions were suggestive of linkage, including 1p13 (psychosis), 1p21 (psychosis), 1q44, 2q24 (suicidal behavior), 2p25 (psychosis), 4p16 (psychosis, suicidal behavior), 5p15, 6p25 (psychosis), 8p22 (psychosis), 8q24, 10q21, 10q25 (suicidal behavior), 10p11 (psychosis), 13q32 and 19p13 (psychosis). Over half the implicated regions were identified using phenotypic subtypes. Several regions - 1p, 1q, 6q, 8p, 13q and 16p - have been previously reported to be linked to bipolar disorder. Our results suggest that dissection of the disease phenotype can enrich the harvest of linkage signals and expedite the search for susceptibility genes. This is the first large-scale linkage scan of bipolar disorder to analyze simultaneously bipolar disorder, psychosis, suicidal behavior, and panic disorder.  相似文献   
992.
993.
994.
This qualitative study aimed to assess factors influencing pregnant women’s decision to seek or avoid antenatal care (ANC) in the Andes of Peru. Open-ended, semi-structured interviews were conducted with 24 women utilizing ANC (+) and 10 women avoiding ANC (?). Interviews were translated to English from Quechua and Spanish, transcribed, and analyzed using grounded theory. Factors influencing ANC? women included: expecting criticism for having additional children; long ANC wait time and inconvenient hours of operation; and masculine gender of health workers. For ANC+ women, motivating factors included: maximizing positive health outcomes; past negative maternity experiences; pressure from family members; and avoidance of rumored fines or fees associated with ANC non-attendance and in-hospital deliveries, respectively. Both ANC+ and ANC? women were fearful and embarrassed about possible criticism for having additional children and the gender of the health workers, yet they weighed these factors differently. To better understand how rural women make decisions about ANC attendance, it is important to consider the value they place on the factors influencing their decision, and their emotional assessment of such issues.  相似文献   
995.
996.
997.
998.
For persons with immediate allergic reactions to mRNA COVID-19 vaccines, skin testing (ST) to the vaccine/excipients (polyethylene glycol[PEG] and polysorbate 80 [PS]) has been recommended, but has unknown accuracy. To assess vaccine/excipient ST accuracy in predicting all-severity immediate allergic reactions upon re-vaccination, systematic review was performed searching Medline, EMBASE, Web of Science, and the WHO global coronavirus database (inception-Oct 4, 2021) for studies addressing immediate (≤4 h post-vaccination) all-severity allergic reactions to 2nd mRNA COVID-19 vaccination in persons with 1st dose immediate allergic reactions. Cases evaluating delayed reactions, change of vaccine platform, or revaccination without vaccine/excipient ST were excluded. Meta-analysis of diagnostic testing accuracy was performed using Bayesian methods. The GRADE approach evaluated certainty of the evidence, and QUADAS-2 assessed risk of bias. Among 20 studies of mRNA COVID-19 first dose vaccine reactions, 317 individuals underwent 578 ST to any one or combination of vaccine, PEG, or PS, and were re-vaccinated with the same vaccine. Test sensitivity for either mRNA vaccine was 0.2 (95%CrI 0.01–0.52) and specificity 0.97 (95%CrI 0.9–1). PEG test sensitivity was 0.02 (95%CrI 0.00–0.07) and specificity 0.99 (95%CrI 0.96–1). PS test sensitivity was 0.03 (95%CrI 0.00–0.0.11) and specificity 0.97 (95%CrI 0.91–1). Combined for use of any of the 3 testing agents, sensitivity was 0.03 (95%CrI 0.00–0.08) and specificity was 0.98 (95%CrI 0.95–1.00). Certainty of evidence was moderate. ST has low sensitivity but high specificity in predicting all-severity repeat immediate allergic reactions to the same agent, among persons with 1st dose immediate allergic reactions to mRNA COVID-19 vaccines. mRNA COVID-19 vaccine or excipient ST has limited risk assessment utility.  相似文献   
999.
Granulomas are key histopathological features of Mycobacterium tuberculosis (Mtb) infection, with complex roles in pathogen control and dissemination. Thus, understanding drivers and regulators of granuloma formation is important for improving tuberculosis diagnosis, treatment, and prevention. Yet, molecular mechanisms underpinning granuloma formation and dynamics remain poorly understood. Here we used low-dose Mtb infection of C57BL/6 mice, which elicits structured lung granulomas composed of central macrophage clusters encased by a lymphocyte mantle, alongside the disorganized lymphocyte and macrophage clusters commonly observed in Mtb-infected mice. Using gene-deficient mice, we observed that Toll-like receptor (TLR) 2 and the TLR-related Radioprotective 105 kDa protein (RP105) contributed to the extent and spatial positioning of pathology in infected lung tissues, consistent with functional cooperation between TLR2 and RP105 in the innate immune recognition of Mtb. In mice infected with the highly virulent Mtb clinical isolate HN878, TLR2, but not RP105, positively regulated the extent of central macrophage regions within structured granulomas. Moreover, RP105, but not TLR2, promoted the formation of structured lung granulomas, suggesting that the functions of RP105 as an innate immune sensor for Mtb reach beyond its roles as TLR2 co-receptor. TLR2 and RP105 contributions to lung pathology are governed by Mtb biology, as neither receptor affected the frequency or architecture of structured granulomas in mice infected with the reference strain Mtb H37Rv. Thus, by revealing distinctive as well as cooperative functions of TLR2 and RP105 in lung pathology, our data identify TLRs as molecular determinants of TB granuloma formation and architecture, and expand understanding of how interactions between innate immune receptors and Mtb shape TB disease manifestation.  相似文献   
1000.
PURPOSE: To understand the characteristics of medical school faculty members who serve on institutional review boards (IRBs) in U.S. academic health centers. METHOD: Between October 2001 and March 2002, a questionnaire was mailed to a stratified random sample of 4,694 faculty members in 121 four-year medical schools in the United States (excluding Puerto Rico). The sample was drawn from the Association of American Medical College's faculty roster database for 1999. The primary independent variable was service on an IRB. Data were analyzed using standard statistical procedures. RESULTS: A total of 2,989 faculty members responded (66.5%). Eleven percent of respondents reported they had served on an IRB in the three years before the study. Of these, 73% were male, 81% were white (non-Hispanic). Virtually all faculty IRB members (94%) conducted some research in the three years before the study, and, among these, 71% reported conducting clinical research, and 47% served as industrial consultants to industry. Underrepresented minority faculty members were 3.2 times more likely than white faculty members to serve on the IRB. Clinical researchers were 1.64 times more likely to be on an IRB than were faculty members who conducted nonclinical research. No significant difference was found in the average number of articles published in the three years before the study comparing IRB faculty to non-IRB faculty. CONCLUSIONS: The faculty members who serve on IRBs tend to have research experience and knowledge that may be used to inform their IRB-related activities. However, the fact that almost half of all faculty IRB members serve as consultants to industry raises potential conflicts of interest.  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