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   2368篇
  免费   194篇
  国内免费   5篇
耳鼻咽喉   36篇
儿科学   71篇
妇产科学   92篇
基础医学   334篇
口腔科学   33篇
临床医学   272篇
内科学   549篇
皮肤病学   58篇
神经病学   216篇
特种医学   37篇
外科学   295篇
综合类   7篇
一般理论   3篇
预防医学   245篇
眼科学   30篇
药学   101篇
中国医学   2篇
肿瘤学   186篇
  2024年   6篇
  2023年   54篇
  2022年   96篇
  2021年   186篇
  2020年   111篇
  2019年   141篇
  2018年   126篇
  2017年   93篇
  2016年   88篇
  2015年   105篇
  2014年   122篇
  2013年   137篇
  2012年   216篇
  2011年   194篇
  2010年   75篇
  2009年   61篇
  2008年   128篇
  2007年   111篇
  2006年   102篇
  2005年   74篇
  2004年   82篇
  2003年   75篇
  2002年   56篇
  2001年   12篇
  2000年   5篇
  1999年   6篇
  1998年   11篇
  1997年   13篇
  1996年   9篇
  1995年   4篇
  1994年   7篇
  1993年   3篇
  1992年   4篇
  1991年   5篇
  1989年   3篇
  1988年   5篇
  1987年   4篇
  1986年   6篇
  1984年   4篇
  1983年   2篇
  1982年   3篇
  1981年   3篇
  1980年   2篇
  1978年   2篇
  1964年   1篇
  1963年   1篇
  1962年   1篇
  1935年   2篇
  1934年   1篇
  1929年   1篇
排序方式: 共有2567条查询结果,搜索用时 15 毫秒
21.
Depressive disorder is a common consequence of interferon α treatment. An understanding of the aetiological processes involved is evolving. HPA axis abnormalities are clearly described in community depressive disorder and represent vulnerability to depression development. We explored whether pre-treatment HPA axis abnormalities influence depression emergence during interferon α treatment. We examined waking HPA axis response via salivary cortisol sampling in 44 non-depressed, chronic hepatitis C infected patients due to commence standard interferon α treatment. Hamilton depression scales and the structured clinical interview for DSM-IV major depressive disorder status were administered monthly during treatment. Major depressive disorder developed in 26 of 44 subjects during interferon-α treatment. The pre-treatment waking cortisol response over 1 h was significantly greater in the subsequent switch to depression group (F=4.23, p=0.046). The waking cortisol response pre-treatment with interferon α appears greater in those subsequently switching to depressive disorder during treatment. This waking response may join other vulnerability factors for depression emergence in this group. This model could prove a valuable tool in understanding non-iatrogenic depressive disorder in the general population and notably the role of cytokines.  相似文献   
22.
23.
24.
As many as 29% of women suffer from migraine headache, yet it remains a poorly understood phenomenon. Our purpose in conducting this pilot study was to determine the relationships among migraine pain, disability, depressive symptomatology, and coping in women. A convenience sample of 34 women was recruited from university and workplace populations. Nineteen women met the International Headache Society criteria for migraine, while 15 women served as a nonmigraine comparison group. Participants completed eight instruments measuring migraine pain, disability, depressive symptomatology, and coping. The two groups of women were not significantly different on demographic variables. Migraineurs scored significantly higher for pain characteristics, disability, depressive symptomatology, and total coping scores.  相似文献   
25.
Three assumptions guiding research and clinical intervention strategies for people coping with sudden, traumatic loss are that (a) people confronting such losses inevitably search for meaning, (b) over time most are able to find meaning and put the issue aside, and (c) finding meaning is critical for adjustment or healing. We review existing empirical research that addresses these assumptions and present evidence from a study of 124 parents coping with the death of their infant and a study of 93 adults coping with the loss of their spouse or child to a motor vehicle accident. Results of these studies indicate that (a) a significant subset of individuals do not search for meaning and yet appear relatively well-adjusted to their loss; (b) less than half of the respondents in each of these samples report finding any meaning in their loss, even more than a year after the event; and (c) those who find meaning, although better adjusted than those who search but are unable to find meaning, do not put the issue of meaning aside and move on. Rather, they continue to pursue the issue of meaning as fervently as those who search but do not find meaning. Implications for both research and clinical intervention are discussed.  相似文献   
26.
Impairment in mental flexibility may be a key component contributing to cardinal cognitive symptoms among mood disorders patients, particularly thought control disorders. Impaired ability to switch from one thought to another might reflect difficulties in either generating new mental states, inhibiting previous states, or both. However, the neural underpinnings of impaired cognitive flexibility in mood disorders remain largely unresolved. We compared a group of mood disorders patients (n = 29) and a group of matched healthy subjects (n = 32) on a novel task‐switching paradigm involving happy and sad faces, that allowed us to separate generation of a new mental set (Switch Cost) and inhibition of the previous set during switching (Inhibition Cost), using fMRI. Behavioral data showed a larger Switch Cost in patients relative to controls, but the average Inhibition Cost did not differ between groups. At the neural level, a main effect of group was found with stronger activation of the subgenual cingulate cortex in patients. The larger Switch Cost in patients was reflected by a stronger recruitment of brain regions involved in attention and executive control, including the left intraparietal sulcus, precuneus, left inferior fontal gyrus, and right anterior cingulate. Critically, activity in the subgenual cingulate cortex was not downregulated by inhibition in patients relative to controls. In conclusion, mood disorder patients have exaggerated Switch Cost relative to controls, and this deficit in cognitive flexibility is associated with increased activation of the fronto‐parietal attention networks, combined with impaired modulation of the subgenual cingulate cortex when inhibition of previous mental states is needed. Hum Brain Mapp 37:1335‐1348, 2016. © 2016 Wiley Periodicals, Inc.  相似文献   
27.
Antiviral therapy with interferon-alpha (IFN-alpha) and pegylated IFN-alpha (PEG-IFN-alpha) for chronic hepatitis C (HCV)-infected kidney recipients remains controversial. IFN-alpha is not recommended in most cases because it induces severe acute graft rejection. However, IFN-alpha, as PEG-IFN-alpha, is associated with a more pronounced immune response, and is well tolerated in HCV-infected liver recipients without causing graft rejection. In combined liver-kidney transplant (LKT) recipients, IFN-alpha has been occasionally used and appears to be well tolerated. All LKT recipients with a functioning kidney and liver having a HCV replication and who needed IFN-alpha therapy have been included in the study. The occurrence of liver and/or renal acute rejection as well as the HCV replication has been collected. A total of 12 LKT patients treated with PEG-IFN-alpha plus ribavirin have been studied. No acute rejection was observed. Renal function remained stable during and after discontinuing treatment, without any graft dysfunction. Two patients had a partial viral response and four had a sustained viral response. All patients, whatever their viral response, had decreased liver-enzyme levels. Response to PEG-IFN-alpha therapy was correlated with steroid dose and transaminase level when PEG-IFN-alpha was started. These data suggest that the combination therapy of PEG-IFN-alpha plus ribavirin did not have a higher risk of acute kidney-graft rejection after liver-kidney transplantation.  相似文献   
28.
Prior studies showed conflicting results regarding the association between 25-hydroxyvitamin D (25(OH)D) levels and mineral metabolism in end-stage renal disease. In order to determine whether the bioavailable vitamin D (that fraction not bound to vitamin D-binding protein) associates more strongly with measures of mineral metabolism than total levels, we identified 94 patients with previously measured 25(OH)D and 1,25-dihydroxyvitamin D (1,25(OH)(2)D) from a cohort of incident hemodialysis patients. Vitamin D-binding protein was measured from stored serum samples. Bioavailable 25(OH)D and 1,25(OH)(2)D were determined using previously validated formulae. Associations with demographic factors and measures of mineral metabolism were examined. When compared with whites, black patients had lower levels of total, but not bioavailable, 25(OH)D. Bioavailable, but not total, 25(OH)D and 1,25(OH)(2)D were each significantly correlated with serum calcium. In univariate and multivariate regression analysis, only bioavailable 25(OH)D was significantly associated with parathyroid hormone levels. Hence, bioavailable vitamin D levels are better correlated with measures of mineral metabolism than total levels in patients on hemodialysis.  相似文献   
29.
30.
The objective of this cross‐sectional study was to define normal sex‐ and age‐dependent values of intra‐articular bone mass and microstructures in the metacarpal heads of healthy individuals by high‐resolution peripheral quantitative computed tomography (HR‐pQCT) and test the effect of rheumatoid arthritis (RA) on these parameters. Human cadaveric metacarpal heads were used to exactly define intra‐articular bone. Healthy individuals of different sex and age categories and RA patients with similar age and sex distribution received HR‐pQCT scans of the second metacarpal head and the radius. Total, cortical, and trabecular bone densities as well as microstructural parameters were compared between 1) the different ages and sexes in healthy individuals; 2) between metacarpal heads and the radius; and 3) between healthy individuals and RA patients. The cadaveric study allowed exact definition of the intra‐articular (intracapsular) bone margins. These data were applied in measuring intra‐articular and radial bone parameters in 214 women and men (108 healthy individuals, 106 RA patients). Correlations between intra‐articular and radial bone parameters were good (r = 0.51 to 0.62, p < 0.001). In contrast to radial bone, intra‐articular bone remained stable until age 60 years (between 297 and 312 mg HA/cm3) but decreased significantly (p < 0.001) in women thereafter (237.5 ± 44.3) with loss of both cortical and trabecular bone. Similarly, RA patients showed significant (p < 0.001) loss of intra‐articular total (263.0 ± 44.8), trabecular (171.2 ± 35.6), and cortical bone (610.2 ± 62.0) compared with sex‐ and age‐adjusted controls. Standard sex‐ and age‐dependent values for physiological intra‐articular bone were defined. Postmenopausal state and RA led to significant decrease of intra‐articular bone. © 2016 American Society for Bone and Mineral Research.  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