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   39038篇
  免费   2253篇
  国内免费   212篇
耳鼻咽喉   443篇
儿科学   1201篇
妇产科学   1085篇
基础医学   3909篇
口腔科学   1296篇
临床医学   3423篇
内科学   8379篇
皮肤病学   698篇
神经病学   2317篇
特种医学   1372篇
外国民族医学   4篇
外科学   7048篇
综合类   907篇
现状与发展   3篇
一般理论   27篇
预防医学   2659篇
眼科学   1398篇
药学   3032篇
  1篇
中国医学   308篇
肿瘤学   1993篇
  2024年   41篇
  2023年   438篇
  2022年   1103篇
  2021年   1716篇
  2020年   1022篇
  2019年   1306篇
  2018年   1622篇
  2017年   1175篇
  2016年   1282篇
  2015年   1380篇
  2014年   1743篇
  2013年   2149篇
  2012年   3247篇
  2011年   3117篇
  2010年   1786篇
  2009年   1528篇
  2008年   2348篇
  2007年   2424篇
  2006年   2127篇
  2005年   1877篇
  2004年   1719篇
  2003年   1439篇
  2002年   1239篇
  2001年   401篇
  2000年   339篇
  1999年   312篇
  1998年   213篇
  1997年   152篇
  1996年   154篇
  1995年   114篇
  1994年   108篇
  1993年   90篇
  1992年   166篇
  1991年   175篇
  1990年   139篇
  1989年   133篇
  1988年   120篇
  1987年   109篇
  1986年   94篇
  1985年   126篇
  1984年   83篇
  1983年   55篇
  1982年   60篇
  1981年   56篇
  1980年   49篇
  1979年   55篇
  1978年   45篇
  1977年   38篇
  1975年   38篇
  1973年   37篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
995.
Molecular Imaging and Biology - The early and accurate diagnosis of locoregional recurrence or metastasis in prostate cancer (PC) has a significant impact on treatment options. Prostatic-specific...  相似文献   
996.
997.
In this study, the in vivo hypoglycemic effect of a donut-shaped polyanion salt (NH4)14[Na@P5W30O110]·31H2O {NaP5W30} and its Ag-containing derivative K14[Ag@P5W30O110]·22H2O·6KCl {AgP5W30}, as well as their hepatotoxicity and nephrotoxicity, was evaluated. In the screening hypoglycemic study, Wistar albino rats with streptozotocin induced diabetes were treated intraperitoneally with three single doses (5, 10, and 20 mg per kg per b.w.) of both investigated polyoxotungstates. The blood glucose levels, measured before and after 2, 4 and 6 h polyoxotungstate application, showed that both studied compounds induced the most pronounced and time dependent glucose lowering effects at the doses of 20 mg kg−1. Thus, daily doses of 20 mg kg−1 were administered to Wistar albino rats orally for 14 days in further toxicity examinations. The serum glucose concentration and biochemical parameters of kidney and liver function, as well as a histopathological analysis of kidney and liver tissues were evaluated 14 days after the polyoxotungstate administration. Both investigated compounds did not induce statistically significant alterations of the serum glucose and uric acid concentrations, as well as some of the liver function markers (serum alanine and aspartate aminotransferases, and alkaline phosphatase activities). However, the significant decrease in serum total protein and albumin concentrations and the increase in biochemical parameters of renal function – serum urea (up to 63.1%) and creatinine concentrations (up to 23.3%) were observed for both polyoxotungstates. In addition, the detected biochemical changes were in accordance with kidney and liver histhopathological analysis. Accordingly, the hepatotoxic and nephrotoxic effects of these potential antidiabetic polyoxotungstates could be considered as mild.

Study of the in vivo hypoglycemic effect, hepatotoxicity and nephrotoxicity of a donut-shaped polyanion salt (NH4)14[Na@P5W30O110]·31H2O {NaP5W30} and its Ag-containing derivative K14[Ag@P5W30O110]·22H2O·6KCl {AgP5W30}.  相似文献   
998.
Correction for ‘Acridinedione as selective flouride ion chemosensor: a detailed spectroscopic and quantum mechanical investigation’ by Nafees Iqbal et al., RSC Adv., 2018, 8, 1993–2003.

The authors regret that the interpretation of the fluorescence spectra of compound 7i published in the original article was incorrect. In the original article, it was reported that upon excitation at 380 nm, the fluorescence spectrum of compound 7i showed two emission bands at 450 nm and 770 nm (Fig. 5b of the original article). The signal at 770 nm (previously reported as an emission band), is instead a second order diffraction (an artefact of diffraction grating/spectrofluorometer monochromator), as revealed from the literature.1,2 The authors thank a reader for highlighting this mistake.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.  相似文献   
999.
To verify the possibility that the pedunculopontine nucleus is a source of glutamatergic terminals in contact with midbrain dopaminergic neurons in the squirrel monkey, we used the anterograde transport of Phaseolus vulgaris-leucoagglutinin in combination with preembedding immunohistochemistry for tyrosine hydroxylase and for calbindin D-28k and postembedding immunocytochemistry for glutamate and for γ-aminobutyric acid. Following tracer injections in the pedunculopontine nucleus, numerous anterogradely labeled fibers emerged from the injection sites to innervate densely the pars compacta of the substantia nigra and ventral tegmental area. The major type of labeled fibers were thin with multiple collaterals and varicosities that established intimate contacts with midbrain dopaminergic neurons. At the electron microscopic level, the anterogradely labeled boutons were medium sized (maximum diameter between 0.9 μm and 2.5 μm) and contained numerous round vesicles and mitochondria. Postembedding immunocytochemistry revealed that 40–60% of anterogradely labeled terminals were enriched in glutamate and formed asymmetric synapses with dendritic shafts of substantia nigra and ventral tegmental area neurons. In triple-immunostained sections, some of the postsynaptic targets to these terminals were found to be dopaminergic. In addition, 30–40% of the anterogradely labeled terminals in both regions displayed immunoreactivity for γ-aminobutyric acid and, in some cases, formed symmetric synapses with dendritic shafts. In conclusion, our results provide the first ultrastructural evidence for the existence of synaptic contacts between glutamate-enriched terminals from the pedunculopontine nucleus and midbrain dopaminergic neurons in primates. Our results also show that the pedunculopontine nucleus is a potential source of γ-aminobutyric acid input to this region. These findings suggest that the pedunculopontine nucleus may play an important role in the modulation of the activity of midbrain dopaminergic cells by releasing glutamate or γ-aminobutyric acid as neurotransmitter. © 1996 Wiley-Liss, Inc.  相似文献   
1000.
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