全文获取类型
收费全文 | 33185篇 |
免费 | 2323篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 303篇 |
儿科学 | 1181篇 |
妇产科学 | 963篇 |
基础医学 | 4279篇 |
口腔科学 | 431篇 |
临床医学 | 4343篇 |
内科学 | 5951篇 |
皮肤病学 | 472篇 |
神经病学 | 3537篇 |
特种医学 | 597篇 |
外国民族医学 | 4篇 |
外科学 | 2978篇 |
综合类 | 329篇 |
一般理论 | 45篇 |
预防医学 | 4617篇 |
眼科学 | 507篇 |
药学 | 2209篇 |
中国医学 | 23篇 |
肿瘤学 | 2794篇 |
出版年
2024年 | 44篇 |
2023年 | 294篇 |
2022年 | 517篇 |
2021年 | 1123篇 |
2020年 | 679篇 |
2019年 | 1035篇 |
2018年 | 1158篇 |
2017年 | 832篇 |
2016年 | 979篇 |
2015年 | 1005篇 |
2014年 | 1328篇 |
2013年 | 1870篇 |
2012年 | 2735篇 |
2011年 | 2956篇 |
2010年 | 1545篇 |
2009年 | 1296篇 |
2008年 | 2377篇 |
2007年 | 2376篇 |
2006年 | 2173篇 |
2005年 | 2042篇 |
2004年 | 1825篇 |
2003年 | 1575篇 |
2002年 | 1594篇 |
2001年 | 205篇 |
2000年 | 170篇 |
1999年 | 201篇 |
1998年 | 307篇 |
1997年 | 238篇 |
1996年 | 168篇 |
1995年 | 178篇 |
1994年 | 134篇 |
1993年 | 119篇 |
1992年 | 69篇 |
1991年 | 47篇 |
1990年 | 48篇 |
1989年 | 39篇 |
1988年 | 40篇 |
1987年 | 36篇 |
1986年 | 34篇 |
1985年 | 18篇 |
1984年 | 20篇 |
1983年 | 30篇 |
1982年 | 25篇 |
1981年 | 18篇 |
1980年 | 11篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1942年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
101.
Johnson JG Cohen P Kotler L Kasen S Brook JS 《Journal of consulting and clinical psychology》2002,70(5):1119-1128
Longitudinal data were used to investigate whether anxiety, depressive, disruptive, personality, or substance use disorders are associated with risk for the development of eating disorders during adolescence or early adulthood. Psychiatric disorders were assessed among 726 youths from a random community sample during adolescence and early adulthood. Depressive disorders during early adolescence were associated with elevated risk for the onset of eating disorders, dietary restriction, purging behavior, and recurrent weight fluctuations after preexisting eating problems and other psychiatric disorders were controlled statistically. Disruptive and personality disorders were independently associated with elevated risk for specific eating or weight problems. The present findings suggest that depressive disorders during early adolescence may contribute to the development of eating disorders during middle adolescence or early adulthood. 相似文献
102.
Comparison of an immunochromatography test with multiplex reverse transcription-PCR for rapid diagnosis of respiratory syncytial virus infections 下载免费PDF全文
Kuroiwa Y Nagai K Okita L Ukae S Mori T Hotsubo T Tsutsumi H 《Journal of clinical microbiology》2004,42(10):4812-4814
A new commercial rapid 10-min one-step immunochromatography (IC) test, SAS RSV test, was compared to another IC test, Directigen EZ RSV, employing RT-PCR as the "gold standard" for detecting respiratory syncytial virus. Of 102 clinical samples, 79 were positive by RT-PCR, 66 (82.5%) were positive with the SAS RSV test, and 55 (69.6%) were positive with Directigen EZ RSV. The specificity of the new test was 91.3% (21 of 23), similar to that of Directigen EZ RSV (100% [23 of 23]). This test performs well enough to be used for patient care. 相似文献
103.
Performance and Cost evaluation of one commercial and six in-house conventional and real-time reverse transcription-pcr assays for detection of severe acute respiratory syndrome coronavirus 总被引:5,自引:0,他引:5 下载免费PDF全文
104.
105.
Paul E. Baer Lisa Berg Garmezy Robert J. McLaughlin Alex D. Pokorny Mark J. Wernick 《Journal of behavioral medicine》1987,10(5):449-466
This study examined alcohol use among seventh graders in relation to life events, daily hassles, the supportive quality of the family environment, coping, and anxiety. Four hundred twenty-five students participated, 228 girls and 197 boys. Stepwise regression and discriminant function analyses indicated that the students reported more alcohol use if they also reported more life events, more daily hassles, and more conflict in the family. A stress-buffering effect of low family conflict on life events could not be substantiated for extent of alcohol use. The results are discussed in the context of the developmental transitions of adolescence. 相似文献
106.
Diagnosis of norwalk virus infection by indirect enzyme immunoassay detection of salivary antibodies to recombinant norwalk virus antigen 总被引:1,自引:0,他引:1
Moe CL Sair A Lindesmith L Estes MK Jaykus LA 《Clinical and diagnostic laboratory immunology》2004,11(6):1028-1034
Simple diagnostic tests are needed for the detection of norovirus (NoV) outbreaks. Salivary antibody assays provide an attractive alternative to collecting and testing serum or stool samples. Antibodies to Norwalk virus (NV) in oral fluid samples were compared with NV antibodies in serum collected from 38 volunteers challenged with NV inoculum. Pre- and postchallenge (day 4, 8, 14, and 21) saliva and serum samples were examined by enzyme immunoassay (EIA) using recombinant NV antigen. Of 18 infected subjects (those who shed NV in stool or who demonstrated immunoglobulin G [IgG] seroconversion), 15 (83%) had > or =4-fold increases in NV-specific salivary IgA and 15 (83%) had > or =4-fold increases in NV-specific salivary IgG when prechallenge and postchallenge saliva samples were compared. When the results of the IgA and IgG assays were combined, all 18 infected subjects showed > or =4-fold increases in NV-specific salivary IgG or IgA postchallenge titers compared to their prechallenge titers. One of 19 uninfected subjects had a > or =4-fold increase in NV-specific salivary IgG. The sensitivity of the combined assay results was 100%, and the specificity was 95%. NV-specific salivary IgA titers peaked around 14 days postchallenge. NV-specific salivary IgG and serum IgG titers continued to rise through 21 days postchallenge. The application of this EIA to an elementary school outbreak indicated that 67% of the subjects with confirmed infections had >4-fold rises in anti-NoV IgA when an antigen in the same genetic cluster as the outbreak virus was used. This is the first documented mucosal antibody response to NoV in children. This EIA provides a useful approach for diagnosing NoV outbreaks. 相似文献
107.
Human Lyme arthritis and the immunoglobulin G antibody response to the 37-kilodalton arthritis-related protein of Borrelia burgdorferi 下载免费PDF全文
Salazar CA Rothemich M Drouin EE Glickstein L Steere AC 《Infection and immunity》2005,73(5):2951-2957
In Borrelia burgdorferi-infected C3H-scid mice, antiserum to a differentially expressed, 37-kDa spirochetal outer-surface protein, termed arthritis-related protein (Arp), has been shown to prevent or reduce the severity of arthritis. In this study, we determined the immunoglobulin G (IgG) antibody responses to this spirochetal protein in single serum samples from 124 antibiotic-treated human patients with early or late manifestations of Lyme disease and in serial serum samples from 20 historic, untreated patients who were followed longitudinally from early infection through the period of arthritis. These 20 patients were representative of the spectrum of the severity and duration of Lyme arthritis. Among the 124 antibiotic-treated patients, 53% with culture-proven erythema migrans (EM) had IgG responses to recombinant glutathione S-transferase (GST)-Arp, as did 59% of the patients with facial palsy and 68% of those with Lyme arthritis. In addition, 75 to 80% of the 20 past, untreated patients had reactivity with this protein when EM was present, during initial episodes of joint pain, or during the maximal period of arthritis. There was no association at any of these three time points between GST-Arp antibody levels and the severity of the maximal attack of arthritis or the total duration of arthritis. Thus, after the first several weeks of infection, 60 to 80% of patients had IgG antibody responses to GST-Arp, but this response did not correlate with the severity or duration of Lyme arthritis. 相似文献
108.
Detection of Chlamydia trachomatis and Neisseria gonorrhoeae by strand displacement amplification and relevance of the amplification control for use with vaginal swab specimens 下载免费PDF全文
Vaginal swab specimens may be preferable to cervical swab or urine specimens for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae because of the ease of specimen collection and transport. The purpose of this study was to evaluate whether vaginal swab specimens are equivalent to cervical swab specimens for the detection of N. gonorrhoeae and C. trachomatis by the Becton Dickinson strand displacement amplification assay (SDA) with the BDProbeTec ET instrument and then to evaluate the use of the amplification control in a clinical research setting. In the first phase, vaginal and cervical swab specimens were obtained from 455 symptomatic women aged 18 to 40 attending primary health care and sexually transmitted disease clinics. Thirty-nine specimens (8.6%) had true-positive results for N. gonorrhoeae and 37 specimens (8.1%) had true-positive results for C. trachomatis. The sensitivity of SDA was superior to that of culture for the detection of N. gonorrhoeae with vaginal swab specimens and equivalent to that of the Roche PCR for the detection of C. trachomatis with cervical swab specimens. In the second phase of the study, 1,411 consecutively collected vaginal swab specimens were evaluated, with 357 (25.3%) specimens giving indeterminate readings on the basis of the result for the amplification control. The prevalences of sexually transmitted pathogens in vaginal swab specimens with and without use of the amplification control were 6.0 and 5.8%, respectively, for C. trachomatis and 3.1 and 3.0%, respectively, for N. gonorrhoeae. Although, vaginal swab specimens were equivalent to cervical swab specimens for the detection of N. gonorrhoeae and C. trachomatis by SDA with respect to sensitivity, one in four vaginal swab specimens yielded an indeterminate result when the amplification control was used. The amplification control has limited value for use with vaginal swab specimens. 相似文献
109.
During the course of an experimentally induced Ebola virus (EBOVA) infection of cynomolgus macaques, peripheral blood mononuclear cells were isolated and characterized by multi-color flow cytometry. Both CD4+ and CD8+ lymphocyte counts decreased 60-70% during the first 4 days after infection. Among CD8+ lymphocytes, this decline was greatest among the CD8(lo) population, which was composed mostly of CD3- CD16+ NK cells. In contrast, the number of CD20+ B lymphocytes in the blood did not significantly change during the course of the infection. Phenotypic analysis of T lymphocyte subsets by flow cytometry failed to show evidence of a robust immune response to the infection. Apoptosis could be detected as early as day 2 postinfection among the CD8+ and CD16+ subsets of lymphocytes. Increased expression of CD95 (Fas) suggests that apoptosis may be induced via signaling through the Fas/Fas-L cascade. In contrast, the number of HLA-DR+ cells increased tenfold in the blood during the course of infection. These data suggest that EBOV may block dendritic cell maturation after infection, thereby inhibiting activation of lymphocytes and eliminating those subsets that are most likely to be capable of mounting an effective response to the virus. 相似文献
110.
Hanfei Xu Karen Schwander Michael R. Brown Wenyi Wang R. J. Waken Eric Boerwinkle L. Adrienne Cupples Lisa de las Fuentes Diana van Heemst Oyomoare Osazuwa-Peters Paul S. de Vries Ko Willems van Dijk Yun Ju Sung Xiaoyu Zhang Alanna C. Morrison D. C. Rao Raymond Noordam Ching-Ti Liu 《European journal of human genetics : EJHG》2021,29(5):839
Recent studies consider lifestyle risk score (LRS), an aggregation of multiple lifestyle exposures, in identifying association of gene-lifestyle interaction with disease traits. However, not all cohorts have data on all lifestyle factors, leading to increased heterogeneity in the environmental exposure in collaborative meta-analyses. We compared and evaluated four approaches (Naïve, Safe, Complete and Moderator Approaches) to handle the missingness in LRS-stratified meta-analyses under various scenarios. Compared to “benchmark” results with all lifestyle factors available for all cohorts, the Complete Approach, which included only cohorts with all lifestyle components, was underpowered due to lower sample size, and the Naïve Approach, which utilized all available data and ignored the missingness, was slightly inflated. The Safe Approach, which used all data in LRS-exposed group and only included cohorts with all lifestyle factors available in the LRS-unexposed group, and the Moderator Approach, which handled missingness via moderator meta-regression, were both slightly conservative and yielded almost identical p values. We also evaluated the performance of the Safe Approach under different scenarios. We observed that the larger the proportion of cohorts without missingness included, the more accurate the results compared to “benchmark” results. In conclusion, we generally recommend the Safe Approach, a straightforward and non-inflated approach, to handle heterogeneity among cohorts in the LRS based genome-wide interaction meta-analyses.Subject terms: Genetics, Risk factors 相似文献