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   21366篇
  免费   1382篇
  国内免费   97篇
耳鼻咽喉   223篇
儿科学   559篇
妇产科学   441篇
基础医学   3352篇
口腔科学   532篇
临床医学   2100篇
内科学   4686篇
皮肤病学   534篇
神经病学   2494篇
特种医学   627篇
外国民族医学   2篇
外科学   1820篇
综合类   109篇
一般理论   13篇
预防医学   1847篇
眼科学   417篇
药学   1341篇
中国医学   78篇
肿瘤学   1670篇
  2024年   36篇
  2023年   208篇
  2022年   412篇
  2021年   693篇
  2020年   465篇
  2019年   655篇
  2018年   700篇
  2017年   533篇
  2016年   634篇
  2015年   746篇
  2014年   883篇
  2013年   1099篇
  2012年   1777篇
  2011年   1889篇
  2010年   1005篇
  2009年   912篇
  2008年   1484篇
  2007年   1485篇
  2006年   1397篇
  2005年   1306篇
  2004年   1211篇
  2003年   1090篇
  2002年   932篇
  2001年   114篇
  2000年   73篇
  1999年   118篇
  1998年   182篇
  1997年   154篇
  1996年   112篇
  1995年   91篇
  1994年   72篇
  1993年   48篇
  1992年   32篇
  1991年   24篇
  1990年   39篇
  1989年   23篇
  1988年   17篇
  1987年   20篇
  1986年   9篇
  1985年   17篇
  1984年   13篇
  1983年   15篇
  1982年   11篇
  1981年   9篇
  1980年   16篇
  1979年   11篇
  1977年   8篇
  1975年   8篇
  1973年   7篇
  1972年   9篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
91.
Lee CZ 《The breast journal》1999,5(5):319-324
▪ Abstract: Comprehensive breast centers are developed for a variety of reasons, but the major motivations are usually to reduce psychological morbidity, develop an interdisciplinary team, provide comprehensive services in a patient-focused manner, improve clinical and emotional outcomes, and develop an organized "system" of care. However, the development of "comprehensive" breast centers presents far more of a challenge than a breast-imaging center and must be undertaken with great care and commitment. If the medical staff and operational issues are not appropriately identified and addressed, the long-term success will be threatened. Each breast center is different, but some of the principal priorities and pitfalls are described. The priorities relate to breast subspecialization, access and coordination, prospective treatment planning, and comprehensive programmatic services. Among the many potential pitfalls, the focus in this article is operational and OncoPolitics. ▪  相似文献   
92.
93.
Summary We have recorded postural performance in 50 HIV-infected patients in different stages of the disease (Walter Reed (WR) stages I–VI) by means of a force measuring platform. The results were compared with 50 age-matched controls. A significant instability was particularly evident when standing on an unstable foot support. In patients standing with eyes closed, postural sway was significantly higher in every patient group (WR I–II:P<0.02, WR III–V:P<0.001, WR VI:P<0.001). Patients in stage WR I–II showed no relevant neurological abnormalities. In agreement with other neurophysiological data in the literature we suggest that postural imbalance could be an early sign of central nervous system penetration of HIV. No correlation with electromyographic or cerebrospinal fluid findings could be found.  相似文献   
94.
d,l-Camphor was detected as a new inducer of hydroxylase in the liver musomes of female mice. After a 2-day inhalation of d,l-camphor, cyt. P-450 and the ethylumbelliferone dealkylase were increased by 250 per cent and the NADPH-cyt. P-450 reductase by 350 per cent. The product [NADPH-cyt. P-450 reductase activity × cyt. P450 concentration] was shown to be a suitable reference parameter for the ethylumbelliferone dealkylase activity in the liver musomes during the treatment with four different inducers. The relative dealkylase activity Q was much decreased during inhalation of cyclohexane or d,l-camphor.
Q = mU ethylumbelliferone dealkylasemU NADPH-cty. P-450 reductase × nmoles cty. P-450/mg protein
Obviously these two inducers preferably enhanced cyt. P-450 species with a low dealkylase activity. The Q-values were reproducible. Q was increased by 100 per cent during induction of a MC-sensitive mouse strain with 3-methylcholanthrene, but it was only moderately decreased by induction with phenobarbital. Corresponding to this, methylcholanthrene is known to selectively induce a cyt. P-448 with high dealkylase activity whereas phenobarbital is known to change the hydroxylase specificity in the liver musomes not very much.  相似文献   
95.
96.
PURPOSE: In recent years, the incidence of cutaneous melanoma has increased more than that of any other cancer. Dacarbazine is considered the gold standard for treatment, having a response rate of 15% to 20%, but most responses are not sustained. Previously, we have shown that short exposure of primary cutaneous melanoma cells to dacarbazine resulted in the upregulation of interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF). The purpose of the present study was to determine how long-term exposure of melanoma cells to dacarbazine would affect their tumorigenic and metastatic potential in vivo. MATERIALS AND METHODS: The primary cutaneous melanoma cell lines SB2 and MeWo were repeatedly exposed in vitro to increasing concentrations of dacarbazine, and dacarbazine-resistant cell lines SB2-D and MeWo-D were selected and examined for their ability to grow and metastasize in nude mice. RESULTS: The dacarbazine-resistant cell lines SB2-D and MeWo-D exhibited increased tumor growth and metastatic behavior in vivo. This increase could be explained by the activation of RAF, MEK, and ERK, which led to the upregulation of IL-8 and VEGF. More IL-8, VEGF, matrix metalloproteinase-2 (MMP-2), and microvessel density (CD-31) were found in tumors produced by SB2-D and MeWo-D in vivo than in those produced by their parental counterparts. No mutations were observed in BRAF. CONCLUSION: Our results have significant clinical implications. Treatment of melanoma patients with dacarbazine could select for a more aggressive melanoma phenotype. We propose that combination treatment with anti-VEGF/IL-8 or MEK inhibitors may potentiate the therapeutic effects of dacarbazine.  相似文献   
97.
It is currently accepted that vinil infections may influence the development of atopy. In the present study we evaluated serum IgE levels as well as the prevalence of symptom-, indicative of utopic disease and EBV antibodies in 353 children aged from I month to 19 years. Antibodies against EBV were detected by immunofluorescence. IgE levels in serum were measured by en/. yme imimmoassay. Dividing ihe study population according to EBV seropositivity and age, we noted that the prevalence of high IgE levels (> 2 s. d.) was, in total, more frequent in the EBV negative (32. 9%) than in the positive subjects (27. 6%). Interestingly, this higher prevalence was found only in the groups aged under six, especially in the 7 to 29 month group, where it was statistically significant (p=0.037), whereas in the 6-19 year group the situation was reversed. Furthermore, selecting only the atopic children younger than 3 years of age with high IgE levels and clinical symptoms of atopy (wheezing and/or dermatitis) it was possible to demonstrate lower EBV seropositivity compared with the normal IgE controls for each group, even though these differences were not statistically significant. In conclusion, the results of our study suggest that, in our selected population, EBV infection in the first years of life is associated with a lower prevalence of high IgE levels.  相似文献   
98.
99.
100.
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