全文获取类型
收费全文 | 18370篇 |
免费 | 1330篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 177篇 |
儿科学 | 632篇 |
妇产科学 | 500篇 |
基础医学 | 2505篇 |
口腔科学 | 195篇 |
临床医学 | 2201篇 |
内科学 | 3426篇 |
皮肤病学 | 323篇 |
神经病学 | 1949篇 |
特种医学 | 494篇 |
外国民族医学 | 5篇 |
外科学 | 1973篇 |
综合类 | 140篇 |
一般理论 | 14篇 |
预防医学 | 2246篇 |
眼科学 | 269篇 |
药学 | 1190篇 |
中国医学 | 13篇 |
肿瘤学 | 1492篇 |
出版年
2024年 | 34篇 |
2023年 | 244篇 |
2022年 | 457篇 |
2021年 | 836篇 |
2020年 | 443篇 |
2019年 | 796篇 |
2018年 | 863篇 |
2017年 | 607篇 |
2016年 | 651篇 |
2015年 | 700篇 |
2014年 | 936篇 |
2013年 | 1078篇 |
2012年 | 1673篇 |
2011年 | 1664篇 |
2010年 | 827篇 |
2009年 | 699篇 |
2008年 | 1145篇 |
2007年 | 1131篇 |
2006年 | 1021篇 |
2005年 | 956篇 |
2004年 | 868篇 |
2003年 | 679篇 |
2002年 | 616篇 |
2001年 | 62篇 |
2000年 | 63篇 |
1999年 | 60篇 |
1998年 | 131篇 |
1997年 | 89篇 |
1996年 | 69篇 |
1995年 | 52篇 |
1994年 | 52篇 |
1993年 | 41篇 |
1992年 | 24篇 |
1991年 | 20篇 |
1990年 | 8篇 |
1989年 | 13篇 |
1988年 | 17篇 |
1987年 | 12篇 |
1986年 | 9篇 |
1985年 | 9篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1980年 | 11篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 13篇 |
1973年 | 3篇 |
1972年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Antigenic properties of HpaA and Omp18, two outer membrane proteins of Helicobacter pylori 总被引:6,自引:0,他引:6 下载免费PDF全文
Outer membrane proteins (OMPs) are incorporated into the outer plasma membrane of Helicobacter pylori and are important for, e.g., ion transport, adherence, structural and osmotic stability, and bacterial virulence but may also be antigenic due to their surface exposure. Previous proteome-based approaches with H. pylori lysates determined a strong serological reaction towards two H. pylori OMPs, HpaA (TIGR HP0797) and Omp18 (TIGR HP1125). PCR was used to detect DNA encoding the two proteins, and a positive signal was found in all H. pylori strains tested. Proteins were cloned and expressed in the human kidney cell line HK293 with the QiaExpressionist system with a C-terminal His tag. Only sera from infected persons showed a positive reaction with the recombinant proteins. Recombinant HpaA (rHpaA) and rOmp18 were incubated with human peripheral blood mononuclear cells and induced secretion of interleukin-12 (IL-12) and IL-10 from these cells. To determine the effect on antigen-presenting cells, human blood monocytic and dendritic cells (DCs) were isolated by magnetic cell separation. rOmp18 and rHpaA strongly stimulated major histocompatibility class II and CD83 expression 7- to 10-fold on isolated DCs. rHpaA and rOmp18 failed to stimulate IL-8 secretion from monocytes but increased secretion of IL-12 and IL-10 from DCs significantly. In summary, HpaA and Omp18 are recognized by human dendritic cells and induce their maturation as well as antigen presentation. HpaA and Omp18 of H. pylori thereby appear to have a specific antigenic potential in humans. 相似文献
102.
Jonathan T. Sims Venkatesh Krishnan Ching-Yun Chang Sarah M. Engle Giacomo Casalini George H. Rodgers Nicoletta Bivi Brian J. Nickoloff Robert J. Konrad Stephanie de Bono Richard E. Higgs Robert J. Benschop Silvia Ottaviani Anabela Cardoso Ajay Nirula Mario Corbellino Justin Stebbing 《The Journal of allergy and clinical immunology》2021,147(1):107-111
103.
Infant rats exhibit sensitive-period odor learning characterized by olfactory bulb neural changes and odor preference acquisitions critical for survival. This sensitive period is coincident with low endogenous corticosterone (CORT) levels and stress hyporesponsivity. The authors hypothesized that low corticosterone levels modulate sensitive-period learning. They assessed the effects of manipulating CORT levels by increasing and removing CORT during (Postnatal Day 8) and after (Postnatal Day 12) the sensitive period. Results show that (a) exogenous CORT prematurely ends sensitive-period odor-shock-induced preferences; (b) adrenalectomy developmentally extends the sensitive period as indicated by odor-shock-induced odor-preference learning in older pups, whereas CORT replacement can reinstate fear learning; and (c) CORT manipulation modulates olfactory bulb correlates of sensitive-period odor learning in a manner consistent with behavior. 相似文献
104.
105.
Sciamanna CN Clark MA Diaz JA Newton S 《International journal of medical informatics》2003,72(1-3):1-8
BACKGROUND: Millions of people use the Internet as a source for health information yet little is understood about how the use of the Internet for health information is related to the doctor-patient relationship. OBJECTIVE: We conducted the present study to understand the association between one's interest in using the Internet for general and quality-oriented health information and attitudes about one's communications with health care provider(s). DESIGN: Cross-sectional survey. SETTING: Four community-based primary care practices in Rhode Island. MEASUREMENTS: A single self-administered survey included items to measure: interest in using the Internet to look for general and quality-oriented information and a patient's perceptions of the degree to which their doctors over the previous year have: (1) given them information and (2) engaged them in the decision-making process. RESULTS: A total of 300 patients completed the survey. Among patients without Internet access, interest in using the Internet for health related activities was less among patients who felt that their doctor gave less information: Odds ratio 0.83 (95% CI, 0.70-0.98) and greater among patients who felt that their doctor engaged them more in decision making: Odds ratio 1.3 (95% CI, 1.1-1.6). Among patients with Internet access, we found no relationship between interest in using the Internet for health related activities and measures of patient-physician communication or patient-physician decision making. CONCLUSIONS: Interest in using the Internet for health information is greater for those who (1) felt their doctors provided less information and (2) felt their doctors engaged them more in the decision-making process, but this is true only for those without access to the Internet. 相似文献
106.
Stephanie Spranger Matthias Spranger Hans-Michael Meinck Gholamali Tariverdian 《American journal of medical genetics. Part A》1995,57(3):425-428
We report on 2 sisters with an autosomal-recessive multiple pterygium syndrome, type Escobar, consisting of multiple pterygia with severe contractures, short stature, and minor facial and external genital anomalies. The striking finding was severe muscular atrophy. We speculate that a neu-romuscular disorder is the underlying pathogenesis of Escobar syndrome. © 1995 Wiley-Liss, Inc. 相似文献
107.
Genetic heterogeneity of the NS3 protease gene in hepatitis C virus genotype 1 from untreated infected patients 总被引:3,自引:0,他引:3
Vallet S Gouriou S Nousbaum JB Legrand-Quillien MC Goudeau A Picard B 《Journal of medical virology》2005,75(4):528-537
NS3 protease is essential for hepatitis C Virus (HCV) replication, and is one of the most promising targets for specific anti-HCV therapy. Its natural polymorphism has not been studied at the quasispecies level. In the present work, the genetic heterogeneity of the NS3 protease gene was analyzed in 17 HCV genotype 1 (5 subtypes 1a and 12 subtypes 1b) samples collected from infected patients before anti-viral therapy. A total of 294 clones were sequenced. Although the protease NS3 is considered to be one of the less variable genes in the HCV genome, variability of both nucleotide and amino acid sequences was found. In variants belonging to 1a and 1b subtypes, 224 and 267 of 543 positions showed one or more nucleotide substitutions, respectively. Forty and 74 of the 181 NS3 amino acid positions showed at least one mutation in HCV-1a and HCV-1b isolates, respectively. Most substitutions were conservative. This substantial polymorphism of the NS3 protease produced by HCV-1a and HCV-1b suggests that, despite the numerous functional and structural constraints, the enzyme is sufficiently flexible to tolerate substitutions. 相似文献
108.
The purpose of this study was to quantify to what extent relative and absolute bladder dose-volume and dose-surface histograms of the planning CT scan were representative for the actual treatment. We used data of 17 patients, who each received 11 repeat CT scans and a planning CT scan. The repeat CT scans were matched on the planning CT scan by the bony anatomy. Clinical treatment plans were used to evaluate the impact of bladder filling changes on the four histogram types. The impact was quantified by calculating for this patient group the correlation coefficient between the planning histogram and the treatment histogram. We found that the absolute dose-surface histogram was the most representative one for the actual treatment. 相似文献
109.
Stephanie L. Santoro Karen Donelan Kelsey Haugen Nicolas M. Oreskovic Amy Torres Brian G. Skotko 《American journal of medical genetics. Part C, Seminars in medical genetics》2021,187(1):70-82
The COVID‐19 pandemic necessitated a rapid transition from in‐person office visits to virtual visits in the Down syndrome specialty program at Massachusetts General Hospital (MGH DSP). We describe the clinic transition to virtual visits in April 2020 and reflect on our six‐month experience in virtual visits. Clinic metrics were tracked. Electronic survey responses were collected from caregivers attending virtual visits. Input from the MGH DSP team was collected. From April to September 2020, we maintained patient volume (45 visits per month) and overall satisfaction score (6.7 out of 7) following a sudden, unanticipated transition to virtual visits. Survey of 17 caregivers attending virtual visits found that most were equipped with technology, had access to a private location, and most were able to access visit without any limitations. Caregivers appreciated the convenience of virtual visits but sometimes missed the personal connection of an in‐person visit. Overall, though, virtual visits were frequently viewed as no different than office visits. Team members identified benefits and challenges of virtual visits, as well as lessons learned from this transition. We were able to maintain multidisciplinary, specialty care with optimal caregiver feedback and sustained number of patient visits. 相似文献
110.
Wong Jasin Ezeife Nnaemezie Kudla Angelika Crown Deborah Trierweiler Robert Capraro Pamela Tomazin Stephanie Su Han Pham Tri Heinemann Allen W. 《Journal of occupational rehabilitation》2022,32(3):464-472
Journal of Occupational Rehabilitation - Purpose The COVID-19 pandemic has disproportionately affected the lives of people with disabilities (PWD). How the pandemic affects the employment of PWD... 相似文献