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   10772篇
  免费   799篇
  国内免费   38篇
耳鼻咽喉   94篇
儿科学   314篇
妇产科学   300篇
基础医学   1456篇
口腔科学   249篇
临床医学   1337篇
内科学   2114篇
皮肤病学   268篇
神经病学   1093篇
特种医学   202篇
外科学   981篇
综合类   75篇
一般理论   16篇
预防医学   1375篇
眼科学   189篇
药学   737篇
中国医学   32篇
肿瘤学   777篇
  2024年   17篇
  2023年   133篇
  2022年   234篇
  2021年   483篇
  2020年   265篇
  2019年   368篇
  2018年   384篇
  2017年   285篇
  2016年   324篇
  2015年   325篇
  2014年   412篇
  2013年   593篇
  2012年   859篇
  2011年   860篇
  2010年   486篇
  2009年   384篇
  2008年   653篇
  2007年   645篇
  2006年   597篇
  2005年   570篇
  2004年   469篇
  2003年   449篇
  2002年   403篇
  2001年   57篇
  2000年   42篇
  1999年   44篇
  1998年   71篇
  1997年   75篇
  1996年   66篇
  1995年   55篇
  1994年   46篇
  1993年   51篇
  1992年   42篇
  1991年   51篇
  1990年   35篇
  1989年   32篇
  1988年   34篇
  1987年   36篇
  1986年   29篇
  1985年   35篇
  1984年   39篇
  1983年   43篇
  1982年   36篇
  1981年   40篇
  1980年   46篇
  1979年   22篇
  1978年   20篇
  1977年   19篇
  1975年   17篇
  1973年   22篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
We have previously demonstrated that p100H mutant mice, which lack a functional Sox6 gene, exhibit skeletal and cardiac muscle degeneration and develop cardiac conduction abnormalities soon after birth. To understand the role of Sox6 in skeletal muscle development, we identified muscle-specific genes differentially expressed between wild-type and p100H mutant skeletal muscles and investigated their temporal expression in the mutant muscle. We found that, in the mutant skeletal muscle, slow fiber and cardiac isoform genes are expressed at significantly higher levels, whereas fast fiber isoform genes are expressed at significantly lower levels than wild-type. Onset of this aberrant fiber type-specific gene expression in the mutant coincides with the beginning of the secondary myotube formation, at embryonic day 15-16 in mice. Together with our earlier report, demonstrating early postnatal muscle defects in the Sox6 null-p100H mutant, the present results suggest that Sox6 likely plays an important role in muscle development.  相似文献   
42.
The isthmo-optic nuclei (ION) and ectopic neurons, which constitute the centrifugal visual system (CVS), are thought to be cholinoceptive and nitrergic. However, it is not clear which neurons express these markers, namely the ones that project to the retina rather than in neurons that only participate in a local circuit. Therefore, to characterize the neurochemical patterns of the centrifugal visual system in the post-hatched chick, retinopetal cells of the isthmo-optic nuclei and the ectopic region were identified via immunolabeling for cholera toxin, a neuronal tracer, which has been injected in the ocular globe. Then, double labeled with acetylcholinesterase histochemistry to reveal cholinergic synapses, or NADPH-diaphorase histochemistry as a nitrergic marker. Briefly, acetylcholinesterase activity was present mainly in cholera toxin labeled cell bodies of the isthmo-optic nucleus and the ectopic region indicating that retinal projecting neurons of centrifugal visual system comprise a cholinoceptive pathway. On the other hand, NADPH-diaphorase histochemistry was present in the neuropile and sparse cell bodies inside of the isthmo-optic nucleus and in ectopic neurons which were not cholera toxin positive suggesting their role in an intrinsic circuit of the centrifugal visual system. These data support the idea that these two neurochemical systems are present in distinct neuronal populations in the centrifugal visual system.  相似文献   
43.
Prevention Science - Screening is an essential prevention practice for a number of health conditions. However, screening coverage remains generally low. Studies that investigate determinants of...  相似文献   
44.
Maternal and Child Health Journal - Low birthweight (LBW) is a significant public health problem in sub-Saharan Africa and LBW in rural Zambia is high. Our study explored the prevalence of LBW for...  相似文献   
45.
Prevention Science - The NAMWEZA intervention was implemented, using a ten-session group format, to build skills targeting psychosocial vulnerabilities and enhancing HIV prevention among people...  相似文献   
46.
Fluorescence-advanced videodermatoscopy is not a widespread diagnostic technique. Its application in dermatology can facilitate the diagnosis of diseases such as cutaneous larva migrans by enabling us to recognize the precise position of larva in vivo on the skin. Using this noninvasive technique, we detected a case of cutaneous larva migrans in a patient.  相似文献   
47.
Campylobacteriosis is a disease of worldwide importance, but aspects of its transmission dynamics, particularly risk factors, are still poorly understood. We used data from a matched case-control study of 4,269 men who have sex with men (MSM) and 26,215 controls, combined with national surveillance data on Campylobacter spp., Salmonella spp., and Shigella spp., to calculate matched odds ratios (mORs) for infection among MSM and controls. MSM had higher odds of Campylobacter (mOR 14, 95% CI 10–21) and Shigella (mOR 74, 95% CI 27–203) infections, but not Salmonella (mOR 0.2, 95% CI 0–13), and were less likely than controls to have acquired Campylobacter infection abroad (χ2 = 21; p<0.001). Our results confirm that sexual contact is a risk factor for campylobacteriosis and also suggest explanations for unique features of Campylobacter epidemiology. These findings provide a baseline for updating infection risk guidelines to the general population.  相似文献   
48.
49.
50.
Although interest in the role of donor-specific antibodies (DSAs) in kidney transplant rejection, graft survival, and histopathological outcomes is increasing, their impact on steroid avoidance or minimization in renal transplant populations is poorly understood. Primary outcomes of graft survival, rejection, and histopathological findings were assessed in 188 patients who received transplants between 2012 and 2015 at the Scripps Center for Organ Transplantation, which follows a steroid avoidance protocol. Analyses were performed using data from the United Network for Organ Sharing. Cohorts included kidney transplant recipients with de novo DSAs (dnDSAs; n = 27), preformed DSAs (pfDSAs; n = 15), and no DSAs (nDSAs; n = 146). Median time to dnDSA development (classes I and II) was shorter (102 days) than in previous studies. Rejection of any type was associated with DSAs to class I HLA (P < .05) and class II HLA (P < .01) but not with graft loss. Although mean fluorescence intensity (MFI) independently showed no association with rejection, an MFI >5000 showed a trend toward more antibody-mediated rejection (P < .06), though graft loss was not independently associated. Banff chronic allograft nephropathy scores and a modified chronic injury score were increased in the dnDSA cohort at 6 months, but not at 2 years (P < .001 and P < .08, respectively). Our data suggest that dnDSAs and pfDSAs impact short-term rejection rates but do not negatively impact graft survival or histopathological outcomes at 2 years. Periodic protocol post-transplant DSA monitoring may preemptively identify patients who develop dnDSAs who are at a higher risk for rejection.  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