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   2507篇
  免费   224篇
  国内免费   9篇
耳鼻咽喉   36篇
儿科学   76篇
妇产科学   71篇
基础医学   458篇
口腔科学   94篇
临床医学   166篇
内科学   496篇
皮肤病学   34篇
神经病学   213篇
特种医学   84篇
外科学   265篇
综合类   19篇
一般理论   1篇
预防医学   235篇
眼科学   76篇
药学   207篇
中国医学   42篇
肿瘤学   167篇
  2023年   21篇
  2022年   41篇
  2021年   90篇
  2020年   57篇
  2019年   70篇
  2018年   94篇
  2017年   63篇
  2016年   71篇
  2015年   65篇
  2014年   101篇
  2013年   96篇
  2012年   159篇
  2011年   143篇
  2010年   84篇
  2009年   82篇
  2008年   118篇
  2007年   130篇
  2006年   122篇
  2005年   111篇
  2004年   106篇
  2003年   108篇
  2002年   81篇
  2001年   65篇
  2000年   78篇
  1999年   88篇
  1998年   21篇
  1997年   15篇
  1996年   17篇
  1995年   10篇
  1994年   15篇
  1993年   14篇
  1992年   41篇
  1991年   36篇
  1990年   34篇
  1989年   39篇
  1988年   31篇
  1987年   23篇
  1986年   25篇
  1985年   16篇
  1984年   20篇
  1983年   18篇
  1975年   7篇
  1974年   8篇
  1973年   9篇
  1971年   9篇
  1970年   11篇
  1969年   11篇
  1967年   7篇
  1966年   10篇
  1965年   8篇
排序方式: 共有2740条查询结果,搜索用时 15 毫秒
31.
32.
33.
AIDS and Behavior - We investigated the rate and predictors of ineffective HIV protection in men who have sex with men (MSM) taking pre-exposure prophylaxis (PrEP) in a prospective cohort study...  相似文献   
34.
Theophylline alone or in the presence of 0.001, 0.01, 0.1 or 1 microgram oestradiol-17 beta/100 g body wt increase uterine RNA and protein content 6 h after administration. Uterine oedema induced by physiological doses of oestradiol-17 beta was increased further in the presence of theophylline. Theophylline decreased the number of eosinophils in the blood and concurrently decreased oestrogen-induced uterine oesinophilia at doses of 0.01, 0.1, 1, 10 or 30 micrograms oestradiol-17 beta/100 g body wt. Oestrogen binding by uterine eosinophils in vitro increased in the presence of theophylline. This effect of theophylline could explain the increase of oestrogen-induced uterine oedema in vivo.  相似文献   
35.
Ketoconazole, an imidazole derivative known to inhibit cytochrome P450-dependent adrenal enzymes was given to a patient with a functioning adrenal rest tumor of the liver in preparation for surgery. The drug was administered in a stepwise manner for 42 days starting with 400 mg and reaching 1 g the last 4 weeks of the trial. Clear clinical improvement was evident early in the trial and was associated with evidence of amelioration of her hypercortisolism and striking changes in serum and urinary levels of steroid hormones and metabolites. Sex steroids in serum and urine fell dramatically from the first day to the end of the trial. Urinary 17-ketosteroid excretion fell from a basal average of 139 mg/24 h to near normal levels within a week of therapy; serum testosterone fell from a basal level of 2.4 to 0.18 ng/ml; serum 17 beta-estradiol fell likewise from 1096 to 150 pg/ml. In contrast, cortisol levels in serum and urine increased in the first 2 weeks of the trial and subsequently fell to values below the basal levels. Similarly, serum 17 alpha-OH-progesterone levels increased 63% above the basal levels by day 6 of the trial and declined afterwards. Nine months after successful tumor resection the patient is apparently cured as judged by steroid hormone levels and physical appearance. We conclude that ketoconazole was effective in blocking tumoral steroidogenesis which resulted in clinical benefit.  相似文献   
36.
OBJECTIVES: a) To determine the rate of H. pylori reinfection after successful eradication in a 4-year follow-up study; and b) To evaluate the contribution of different factors in the infection relapse. PATIENTS AND METHODS: A total of 208 patients (age range 18-81 years; average 50 years; 87 women) who had been successfully treated for H. pylori infection were included. Annually, urea breath test was assessed to determine H. pylori status after eradication. Age, sex, rural/urban environment, smoking habit, treatment regimens against H. pylori and urea breath test values were evaluated. Results: reinfection occurred in 9,6% of patients observed, 6,7% (14/208) in the first year, 1,9% (4/208) in the second year, 1% (2/208) in the third and 0% in the forth. Risk factors for infection recurrence were younger age and higher values of urea breath test in the multivariante analysis. CONCLUSIONS: annual reinfection rate was 2,4 pacients-year. Younger patients and higher values of urea breath test were factors associated with a higher rate of reinfection relapse. Annually, urea breath test should be performed to detect reinfection in order to avoid ulcer complications.  相似文献   
37.
38.
Righesso  L. A. R.  Terekhov  M.  Götz  H.  Ackermann  M.  Emrich  T.  Schreiber  L. M.  Müller  W. E. G.  Jung  J.  Rojas  J. P.  Al-Nawas  B. 《Clinical oral investigations》2021,25(10):5843-5854
Clinical Oral Investigations - Micro-computed tomography (μ-CT) and histology, the current gold standard methods for assessing the formation of new bone and blood vessels, are invasive and/or...  相似文献   
39.
The objective of this study was to investigate if there is specific host-parasite association in Chilean populations of Trypanosoma cruzi. For this purpose, two groups of parasites were analyzed, one from chronic chagasic patients, and the other from Triatoma infestans triatomines in three regions of the country. The first group consisted of four types of samples: parasites from peripheral blood of non-cardiopathic T. cruzi infected patients (NB); parasites from their corresponding xenodiagnosis (NX); parasites from peripheral blood of T. cruzi infected cardiopathic patients (CB) and parasites from their xenodiagnostics (CX). The T. infestans sample in turn was from three regions: III, V and M (Metropolitan). The genetic differentiation by the Fisher exact method, the lineage distribution of the samples, the molecular phylogeny and the frequency of multiclonality were analysed. The results show that not only are the groups of T. cruzi clones from Chagas disease patients and vectors genetically differentiated, but also all the sub-groups (NB, NX, CB and CX) from the III, V and M regions. The analysis of lineage distribution was concordant with the above results, because significant differences among the percentages of TcI, TcIII and hybrids (TcV or TcVI) were observed. The phylogenetic reconstruction with these Chilean T. cruzi samples was coherent with the above results because the four chagasic samples clustered together in a node with high bootstrap support, whereas the three triatomine samples (III, V and M) were located apart from that node. The topology of the tree including published T. cruzi clones and isolates was concordant with the known topology, which confirmed that the results presented here are correct and are not biased by experimental error. Taken together the results presented here are concordant with a specific host-parasite association between some Chilean T. cruzi populations.  相似文献   
40.
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