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   3086篇
  免费   255篇
  国内免费   10篇
耳鼻咽喉   65篇
儿科学   73篇
妇产科学   88篇
基础医学   476篇
口腔科学   199篇
临床医学   374篇
内科学   643篇
皮肤病学   38篇
神经病学   171篇
特种医学   176篇
外科学   568篇
综合类   34篇
预防医学   125篇
眼科学   37篇
药学   139篇
中国医学   1篇
肿瘤学   144篇
  2023年   16篇
  2022年   22篇
  2021年   44篇
  2020年   34篇
  2019年   50篇
  2018年   55篇
  2017年   57篇
  2016年   71篇
  2015年   71篇
  2014年   100篇
  2013年   129篇
  2012年   199篇
  2011年   228篇
  2010年   144篇
  2009年   125篇
  2008年   216篇
  2007年   206篇
  2006年   179篇
  2005年   201篇
  2004年   156篇
  2003年   147篇
  2002年   140篇
  2001年   60篇
  2000年   51篇
  1999年   43篇
  1998年   36篇
  1997年   20篇
  1996年   12篇
  1995年   15篇
  1994年   24篇
  1993年   20篇
  1992年   42篇
  1991年   37篇
  1990年   31篇
  1989年   23篇
  1988年   21篇
  1987年   37篇
  1986年   21篇
  1985年   34篇
  1984年   19篇
  1983年   20篇
  1981年   11篇
  1979年   17篇
  1976年   11篇
  1975年   13篇
  1974年   10篇
  1973年   11篇
  1972年   15篇
  1971年   16篇
  1970年   14篇
排序方式: 共有3351条查询结果,搜索用时 15 毫秒
101.
OBJECTIVE: The objective of this study was to evaluate the impact of initiation of insulin therapy, metabolic control and structured patient education on the diabetes-related quality of life (QoL) in insulin-treated patients with type 2 diabetes mellitus. METHODS: This prospective study was conducted with 71 consecutively recruited patients with insulin-treated diabetes at the University hospital. All patients participated an inpatient diabetes treatment and teaching program (DTTP) for conventional insulin therapy (mean age 68.9 years, HbA1c 10.1+/-1.4%, diabetes duration 11.2 years (range: 0-25.5 years), body-mass-index 28.7+/-5.7kg/m(2). Diabetes-related quality of life was assessed before and 6 months after participation in the DTTP using the standardized questionnaire of Lohr analysing the subscales: social relations, physical complaints, worries about the future, dietary restrictions, fear of hypoglycaemia, and daily struggles. RESULTS: Only patients switched on insulin therapy showed significant improvement in diabetes-related quality of life 6 months after participation in the DTTP (p=0.03), fewer physical complaints (p=0.03), fewer worries about the future (p=0.02), fewer daily struggles (p=0.01) and less fear of hypoglycaemia (p<0.001), while patients, who were already on insulin therapy showed no improvements in diabetes-related quality of life. Though, residual analysis reveals that effects on patients' QoL are mainly caused by improvements in metabolic control. CONCLUSIONS: Improvements in metabolic control have a significant effect on different diabetes-related quality of life domains in patients with diabetes mellitus. PRACTICE IMPLICATIONS: Appropriate interventions resulting in better metabolic control, such as starting on insulin therapy within a structured patient education program seem to be an effective approach to improve patients' diabetes-related quality of life.  相似文献   
102.
103.
A fluorescence-based technique was established to trace intracellular sporozoites of Eimeria bovis for tests on gliding motility, invasion, replication and quantification of infection rates in cultured bovine umbilical vein endothelial cells (BUVEC) by laser scanning confocal microscopy and flow cytometry (FCM) analyses. Employing the fluorescent dye 5(6)-carboxyfluorescein diacetate succinimidyl ester (CFSE), we determined its effects on sporozoites at various concentrations and duration of staining. More than 98% of sporozoites were labelled with the dye at a concentration of 2.5 μM. Staining was predominantly found in refractile bodies and presumptive micronemes. Upon infection of BUVEC, CFSE-labelled sporozoites developed into fluorescent immature macromeronts, which were traceable inside the cells until 22 days postinfection (p. i.). Consistent with a peripheral localisation of the fluorescence signal in macromeronts merozoites released from these lacked detectable fluorescence. As example of use, a multicolour FCM approach for the simultaneous determination of E. bovis infection and host cell surface molecule expression was established. The approach proved suitable to quantify major histocompatibility complex (MHC-I) and MHC-II expression, thereby clearly distinguishing between infected and uninfected BUVEC up to day 14 p. i. In conclusion, CFSE labelling of E. bovis sporozoites facilitates monitoring of intracellular stages in vitro and will be a highly useful tool for studying host cell responses towards parasite invasion.  相似文献   
104.

Background

Little is known about regulatory CD4 T cells (Tregs) in the context of HIV vaccines. Tregs can be differentiated into resting (FoxP3+CD45RA+ – rTregs), activated (FoxP3HighCD45RA? – aTregs) and memory (FoxP3LowCD45RA? – mTregs). Tregs, as CD4 T cells, are also frequent targets for HIV infection. We studied how the abundance and phenotypes of Tregs in terms of activation status and expression of HIV-1 binding molecules would have changed during vaccination in healthy volunteers participating in a phase IIa HIV vaccine clinical trial. Subjects were primed three times with HIVIS-DNA and boosted twice with MVA-CMDR-HIV alone (n?=?12) or MVA-CMDR combined with protein CN54rgp140 (n?=?13). The proportions of β7 integrin in all CD4 T cells and in the Tregs subset decreased moderately after the final vaccination (p?=?0.001 and p?=?0.033, respectively) and the rTregs proportion within the total Tregs were also decreased after the final vaccination (p?=?0.038). All these proportions returned to normal values within the three months after the final vaccination. The magnitude of HIV-Envelope-specific IFNγ?+?T cells after vaccination (r?=?0.66; p?=?0.021) correlated directly with the proportion of Tregs, and correlated inversely correlated with ratios of Th17/Tregs (r?=??0.75; p?=?0.0057) and Th17/mTregs (r?=??0.78; p?=?0.0065). Higher titers of IgG gp140 antibodies were observed in subjects with higher mTregs proportions (r?=?0.52; p?=?0.022). Interestingly, pre-vaccination levels of mTregs correlated with vaccine-induced Env-binding antibodies (r?=?0.57; p?=?0.01) and presence of neutralizing antibodies (r?=?0.61; p?=?0.01), while the pre-vaccination Th17/mTregs ratio correlated inversely with the magnitude of cellular IFN-γ ELISpot responses (r?=??0.9; p?=?0.002). Taken together, these results suggest that pre- and post-vaccination Tregs, their activation status, the Th17/Tregs ratio and other host factors affecting Treg abundance, have an impact on the magnitude of HIV vaccine-induced immune responses. Moreover, the DNA-HIVIS/MVA-HIV regimen, alone or in combination with CN54rgp140 induced moderate and temporary alterations of the Tregs activation status. We also show a decrease in expression of the HIV-1 ligand β7 integrin on Tregs and all CD4 T cells.  相似文献   
105.
Eosinophilia‐associated myeloid neoplasms with rearrangement of chromosome bands 5q31‐33 are frequently associated with PDGFRB fusion genes, which are exquisitely sensitive to treatment with imatinib. In search for novel fusion partners of PDGFRB, we analyzed three cases with translocation t(5;20)(q33;p11), t(5;14)(q33;q32), and t(5;17;14)(q33;q11;q32) by 5′‐rapid amplification of cDNA ends polymerase chain reaction (5′‐RACE‐PCR) and DNA‐based long‐distance inverse PCR (LDI‐PCR) with primers derived from PDGFRB. LDI‐PCR revealed a fusion between CCDC88C exon 25 and PDGFRB exon 11 in the case with t(5;17;14)(q33;q11;q32) while 5′‐RACE‐PCR identified fusions between CCDC88C exon 10 and PDGFRB exon 12 and between DTD1 exon 4 and PDGFRB exon 12 in the cases with t(5;14)(q33;q32) and t(5;20)(q33;p11), respectively. The PDGFRB tyrosine‐kinase domain is predicted to be retained in all three fusion proteins. The partner proteins contained coiled‐coil domains or other domains, which putatively lead to constitutive activation of the PDGFRB fusion protein. In vitro functional analyses confirmed transforming activity and imatinib‐sensitivity of the fusion proteins. All three patients achieved rapid and durable complete hematologic remissions on imatinib. © 2014 Wiley Periodicals, Inc.  相似文献   
106.

Purpose  

To assess reliability of wall shear stress (WSS) calculations using computational fluid dynamics (CFD) dependent on inflow in internal carotid artery aneurysms (ICA).  相似文献   
107.
Regulative mechanisms of chondrocyte adhesion   总被引:3,自引:0,他引:3  
Interaction between chondrocytes and extracellular matrix is considered a key factor in the generation of grafts for matrix-associated chondrocyte transplantation. Therefore, our objective was to study the influence of differentiation status on cellular attachment. Adhesion of chondrocytes to collagen type II increased after removal from native cartilage up to the third day in monolayer in a dose-dependent manner. Following dedifferentiation after the second passage, adhesion to collagen types I (-84%) and II (-46%) decreased, whereas adhesion to fibrinogen (+59%) and fibronectin (+43%) increased. A cartilage construct was developed based on a clinically established collagen type I scaffold. In this matrix, more than 80% of the cells could be immobilized by mechanisms of adhesion, filtration, and cell entrapment. Confocal laser microscopy revealed focal adhesion sites as points of cell-matrix interaction, as well as collagen type II expression in the cartilage graft after two weeks of in vitro cultivation. Basic fibroblast growth factor (bFGF) treated chondrocytes showed increased adhesion to collagen types I and II, fibronectin, and fibrinogen. Attachment to these investigated proteins significantly enhanced cell proliferation. Matrix design in cartilage engineering must meet the biological demands of amplified cells, because adhesion of chondrocytes depends on their differentiation status and is regulated by bFGF.  相似文献   
108.
109.
The performance of nucleic acid amplified tests (NAAT) for Chlamydia trachomatis at the cervix and in urine was examined in 3,551 women, and the impacts of clinical findings (age, endocervical and urethral inflammation, menses, and gonococcal coinfection) were assessed. Ligase chain reaction (LCR) and first-generation uniplex PCR were studied relative to an unamplified DNA probe (PACE2) and to an expanded, independent diagnostic reference standard. Relative to the expanded standard, cervical or urine LCR was generally the most sensitive test in most subgroups. Increased detection by NAAT of cervical C. trachomatis over PACE2 was highest among women without mucopurulent endocervical discharge versus those with (relative increase in positivity with cervical LCR, 46%) and among women > or =20 years old versus younger women (relative increase in positivity with cervical LCR, 45%). The sensitivity of cervical PCR was highest when mucopurulent endocervical discharge was present (84%) and highest for cervical LCR when cervical gonococcal coinfection was detected (91%). Urethral inflammation was associated with higher sensitivities of urine LCR (86 compared to 70% when inflammation was absent) and PCR (82 compared to 62% when inflammation was absent). Menses had no effect on test performance. The effects of patient characteristics on test specificities were less pronounced and were closely related to observed sensitivities. These findings support expanded use of NAAT for screening and diagnosis of C. trachomatis in diverse clinical populations of women.  相似文献   
110.
To identify the most rapid and reliable technique for recovery and identification of Staphylococcus aureus small-colony variants (SCVs), the colonial appearance of 106 isolates representing SCVs and the normal phenotype were evaluated on two newly described chromogenic agar media. Although almost all of the SCVs grew on the chromogenic agar media, they did not exhibit a change of color. In comparison with conventional media, S. aureus ID agar (SAID; bioMerieux, La Balme Les Grottes, France) showed the most reliable results, with 49 of 53 SCVs tested growing either as an SCV colony or with a normal phenotype after only 24 h of incubation. Growth of SCVs was often not detected before 72 h of incubation on some of the media tested. In conclusion, the most accurate and rapid method to detect both the species S. aureus and the SCV phenotype is to inoculate specimens onto both Columbia blood agar and SAID.  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