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   9100篇
  免费   750篇
  国内免费   34篇
耳鼻咽喉   57篇
儿科学   314篇
妇产科学   228篇
基础医学   1406篇
口腔科学   94篇
临床医学   1167篇
内科学   1685篇
皮肤病学   142篇
神经病学   1035篇
特种医学   146篇
外科学   994篇
综合类   63篇
一般理论   14篇
预防医学   1147篇
眼科学   151篇
药学   597篇
中国医学   16篇
肿瘤学   628篇
  2024年   23篇
  2023年   171篇
  2022年   258篇
  2021年   487篇
  2020年   360篇
  2019年   427篇
  2018年   414篇
  2017年   335篇
  2016年   348篇
  2015年   332篇
  2014年   423篇
  2013年   527篇
  2012年   794篇
  2011年   781篇
  2010年   394篇
  2009年   359篇
  2008年   531篇
  2007年   597篇
  2006年   504篇
  2005年   446篇
  2004年   393篇
  2003年   334篇
  2002年   284篇
  2001年   36篇
  2000年   26篇
  1999年   30篇
  1998年   57篇
  1997年   24篇
  1996年   19篇
  1995年   16篇
  1994年   18篇
  1993年   7篇
  1992年   12篇
  1991年   14篇
  1990年   3篇
  1989年   4篇
  1987年   7篇
  1986年   6篇
  1985年   6篇
  1984年   7篇
  1983年   5篇
  1981年   7篇
  1980年   4篇
  1979年   6篇
  1977年   5篇
  1975年   4篇
  1974年   3篇
  1971年   3篇
  1937年   2篇
  1933年   2篇
排序方式: 共有9884条查询结果,搜索用时 46 毫秒
991.
Overexpression of erbB2 is associated with resistance to apoptosis. We explored whether high level of erbB2 expression by cancer cells allows their targeting using an erbB2-binding peptide (LTVSPWY) attached to the proapoptotic alpha-tocopheryl succinate (alpha-TOS). Treating erbB2-low or erbB2-high cells with alpha-TOS induced similar levels of apoptosis, whereas alpha-TOS-LTVSPWY induced greater levels of apoptosis in erbB2-high cells. alpha-TOS rapidly accumulated in erbB2-high cells exposed to alpha-TOS-LTVSPWY. The extent of apoptosis induced in erbB2-high cells by alpha-TOS-LTVSPWY was suppressed by erbB2 RNA interference as well as by inhibition of either endocytotic or lysosomal function. alpha-TOS-LTVSPWY reduced erbB2-high breast carcinomas in FVB/N c-neu transgenic mice. We conclude that a conjugate of a peptide targeting alpha-TOS to erbB2-overexpressing cancer cells induces rapid apoptosis and efficiently suppresses erbB2-positive breast tumors.  相似文献   
992.
The purpose of this study was to investigate the effect of childhood cancer and its treatment on self-reported health-status in 10,189 adult survivors of childhood cancer in Britain. Age- and sex-adjusted scores on the SF-36 Mental and Physical Component Summary scales (MCS, PCS, respectively) were compared between survivors and UK norms, and between subgroups of survivors, by multiple regression. Survivors had comparable scores to UK-norms on the MCS scale (difference (D) = -0.1, 99% CI: -0.5, 0.3). The difference in scores between survivors and UK-norms on the PCS scale varied by age (p(heterogeneity) < 0.001). Young survivors (16-19 years) scored similarly to UK-norms (D = 0.5, (-1.1, 2.2), whereas the age groups of 25 and older scored statistically and clinically significantly below UK-norms (all p-values < 0.0001), with Ds ranging between -2.3 (-3.5, -1.2) and -3.7 (-5.0, -2.4). Survivors of central nervous system (CNS) and bone tumors scored significantly (p-value at all ages <0.003) below UK-norms on the PCS scale. Specifically, these survivors were substantially more limited in specific daily activities such as, for example, walking a mile (40, 63%, respectively) when compared to UK-norms (16%). In conclusion, childhood cancer survivors rate their mental health broadly similarly to those in the general population. Survivors of CNS and bone tumors report their physical health-status to be importantly below population norms. Although self-reported physical health is at least as good as in the general population among young survivors, this study suggests that perceived physical health declines more rapidly over time than in the general population.  相似文献   
993.
Mantle cell lymphoma (MCL) is characterized by over-expression of cyclin Dl as a result of the characteristic t(11;14)(q13;q32). However, this translocation alone has proven not to be sufficient for lymphomagenesis, suggesting the involvement of additional alterations. We have characterized 35 cases of MCL by array comparative genomic hybridization with an average resolution of 0.97 Mb distributed over the complete human genome. The most common alterations were losses in 1p13.2-p31.1, 6q16.2-q27, 8p21.3, 9p13.2-p24.3, 9q13-q31.3, 11q14.3-q23.3, 13q14.13-q21.31, 13q33.1-q34, and 22q11.23-q13.33 and gains involving 3q21.2-q29, 7p12.1-p22.3, 8q24.13-q24.23, and 18q21.33-q22.3. Four homozygous deletions were identified in totally three patients; two overlapping at 1p32.3, and two adjacent at 13q32.3. The homozygous deletions at 1p32.3 cover the CDKN2C locus (coding for p18), while the region at 13q32.3 does not encompass any known tumor suppressor genes. A gain in 3q was significantly associated with shorter survival (P=0.047).  相似文献   
994.
995.
Chronic Kidney Disease (CKD) is a common diagnosis in the small animal population. In the UK, 3.6% of cats may experience CKD and renal disorders were the most common cause of mortality in cats over 5 years of age. In dogs, the reported prevalence of CKD is 0.37%, with a median (95% Confidence Interval) survival time from diagnosis of 226 (112–326) days. This article will review the main concepts of renal physiology and discuss considerations when anaesthetising a dog or a cat with CKD.  相似文献   
996.
Childhood adversity (CA) may increase the risk for later developing of personality disorder (PD). However, less is known about the association between cumulative CA and PD, and the role of childhood psychopathology and school performance. The current study examined the relationship between a range of CAs and a diagnosis of PD in young adulthood, and the roles of childhood psychopathology and school performance in this relationship. All individuals born in Stockholm County 1987–1991 (n = 107,287) constituted our cohort. Seven CAs were measured between birth and age 14: familial death, parental criminality, parental substance abuse and psychiatric morbidity, parental separation and/or single-parent household, household public assistance and residential instability. Individuals were followed from their 18th birthday until they were diagnosed with PD or until end of follow-up (December 31st 2011). Adjusted estimates of risk of PD were calculated as hazard ratios (HR) with 95% confidence intervals (CI). Associations were observed between cumulative CA and PD. During the follow-up 770 individuals (0.7%) were diagnosed with PD. Individuals exposed to 3+ CAs had the highest risks of being diagnosed with PD (HR 3.0, 95% CI 2.4–3.7). Childhood psychopathology and low school grades further increased the risk of PD among individuals exposed to CA. Cumulative CA is strongly associated with a diagnosis of PD in young adulthood. Our findings indicate that special attention should be given in schools and health services to children exposed to adversities to prevent decline in school performance, and to detect vulnerable individuals that may be on negative life-course trajectories.  相似文献   
997.
998.
Wnts are a family of secreted proteins that regulate multiple steps of neural development and stem cell differentiation. Two of them, Wnt1 and Wnt5a, activate distinct branches of Wnt signaling and individually regulate different aspects of midbrain dopaminergic (DA) neuron development. However, several of their functions and interactions remain to be elucidated. Here, we report that loss of Wnt1 results in loss of Lmx1a and Ngn2 expression, as well as agenesis of DA neurons in the midbrain floor plate. Remarkably, a few ectopic DA neurons still emerge in the basal plate of Wnt1−/− mice, where Lmx1a is ectopically expressed. These results indicate that Wnt1 orchestrates DA specification and neurogenesis in vivo. Analysis of Wnt1−/−;Wnt5a−/− mice revealed a greater loss of Nurr1+ cells and DA neurons than in single mutants, indicating that Wnt1 and Wnt5a interact genetically and cooperate to promote midbrain DA neuron development in vivo. Our results unravel a functional interaction between Wnt1 and Wnt5a resulting in enhanced DA neurogenesis. Taking advantage of these findings, we have developed an application of Wnts to improve the generation of midbrain DA neurons from neural and embryonic stem cells. We thus show that coordinated Wnt actions promote DA neuron development in vivo and in stem cells and suggest that coordinated Wnt administration can be used to improve DA differentiation of stem cells and the development of stem cell-based therapies for Parkinson’s disease.  相似文献   
999.
Prion disease incubation time in mice is determined by many factors including genetic background. The prion gene itself plays a major role in incubation time; however, other genes are also known to be important. Whilst quantitative trait loci (QTL) studies have identified multiple loci across the genome, these regions are often large, and with the exception of Hectd2 on Mmu19, no quantitative trait genes or nucleotides for prion disease incubation time have been demonstrated. In this study, we use the Northport heterogeneous stock of mice to reduce the size of a previously identified QTL on Mmu15 from approximately 25 to 1.2 cM. We further characterised the genes in this region and identify Cpne8, a member of the copine family, as the most promising candidate gene. We also show that Cpne8 mRNA is upregulated at the terminal stage of disease, supporting a role in prion disease. Applying these techniques to other loci will facilitate the identification of key pathways in prion disease pathogenesis.  相似文献   
1000.
Being hearing-impaired in everyday life can be a challenge in itself; however, when I started at my current job I found the staff were fascinated by my implant. To me, my implant is a normal part of my life and quite often I forget that other people may have questions about how I hear compared to them. I thought I would try and answer a few of these questions on behalf of some of the other hearing-impaired Veterinary Nurses I have communicated with. Hopefully it will give some insight into how some VNs deal with being in practice.  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