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   6614篇
  免费   386篇
  国内免费   29篇
耳鼻咽喉   56篇
儿科学   169篇
妇产科学   109篇
基础医学   932篇
口腔科学   560篇
临床医学   488篇
内科学   1406篇
皮肤病学   149篇
神经病学   483篇
特种医学   286篇
外科学   605篇
综合类   105篇
一般理论   1篇
预防医学   575篇
眼科学   141篇
药学   628篇
中国医学   80篇
肿瘤学   256篇
  2023年   55篇
  2022年   131篇
  2021年   206篇
  2020年   131篇
  2019年   170篇
  2018年   234篇
  2017年   155篇
  2016年   154篇
  2015年   173篇
  2014年   279篇
  2013年   344篇
  2012年   498篇
  2011年   523篇
  2010年   316篇
  2009年   242篇
  2008年   389篇
  2007年   411篇
  2006年   295篇
  2005年   286篇
  2004年   262篇
  2003年   195篇
  2002年   167篇
  2001年   128篇
  2000年   123篇
  1999年   112篇
  1998年   87篇
  1997年   74篇
  1996年   58篇
  1995年   44篇
  1994年   41篇
  1993年   33篇
  1992年   57篇
  1991年   47篇
  1990年   46篇
  1989年   58篇
  1988年   49篇
  1987年   38篇
  1986年   37篇
  1985年   48篇
  1984年   18篇
  1983年   24篇
  1979年   18篇
  1978年   21篇
  1977年   17篇
  1976年   16篇
  1974年   17篇
  1973年   22篇
  1970年   14篇
  1969年   16篇
  1967年   14篇
排序方式: 共有7029条查询结果,搜索用时 8 毫秒
1.
2.
This is a review of 4.690 necropsies and 24.209 surgical pathology specimens describing the association between megacolon chagasic and malignant tumors of the large bowel. The prevalence of malignant tumors of the large bowel was not higher in megacolon.  相似文献   
3.
Opioid receptor binding was evaluated in parahippocampal cortex (PHC) obtained from patients with intractable mesial temporal lobe epilepsy (MTLE) with and without subacute high frequency electrical stimulation (HFS) in this brain area. Mu, delta and nociceptin receptor binding was determined by autoradiography in PHC of five patients (ESAE group) with MTLE history of 14.8 +/- 2.5 years and seizure frequency of 11 +/- 2.9 per month, two of them (40%) with mesial sclerosis. This group demonstrated antiepileptic effects following subacute HFS (130 Hz, 450 micros, 200-400 microA), applied continuously during 16-20 days in PHC. Values were compared with those obtained from patients with severe MTLE (history of 21.7 +/- 2.8 years and seizure frequency of 28.2 +/- 14 per month) in whom electrical stimulation did not induce antiepileptic effects (ESWAE group, n = 4), patients with MTLE in whom no electrical stimulation was applied (MTLE group, n = 4) and autopsy material acquired from subjects without epilepsy (n = 4 obtained from three subjects). Enhanced 3H-DAMGO (MTLE, 755%; ESAE, 375%; ESWAE, 693%), 3H-DPDPE (MTLE, 242%; ESAE, 80%; ESWAE, 346%) and 3H-nociceptin (MTLE, 424%; ESAE, 217%; ESWAE, 451%) binding was detected in the PHC of all epileptic groups. However, tissue obtained from ESAE group demonstrated lower opioid receptor binding (3H-DAMGO, 44.5%, p < 0.05; 3H-DPDPE, 47%, p < 0.05; 3H-nociceptin, 39.3%, p < 0.5) when compared with MTLE group. The present results indicate that a high effectiveness to the antiepileptic effects induced by HFS is associated with reduced opioid peptide binding.  相似文献   
4.
Surgical procedures for the mammary region currently are assuming an important role in body-contouring surgery. Enhancement of results is a constant challenge to the plastic surgeon. A simple and efficient maneuver for resection of the breast’s lateral pole based on the mammoplasty technique of Professor Ivo Pitanguy is described. This study realized at the Private Clinic Sérgio Carreir?o, Rio de Janeiro, RJ, Brazil.  相似文献   
5.
6.
7.
BACKGROUND: In general practice, acute sinusitis is frequently diagnosed and treated with antibiotics. OBJECTIVE: This study aimed to determine the evidence for the effectiveness of antibiotic treatment in acute maxillary sinusitis in adults by assessing the methodological quality of placebo-controlled double-blind randomized trials. METHOD: An evaluation by four raters through a 35-item scoring-scale for internal and external validity of all placebo-controlled double-blind randomized trials on acute sinusitis found between January 1966 and July 1996. RESULTS: Eighty-five trials were excluded because they were not placebo-controlled, double-blind, randomized, or were carried out in patients with chronic sinusitis or in children. The three remaining trials were performed in different populations (one in general practice) between 1973 and 1978. Only one study claimed superiority of antibiotic treatment. Different inclusion criteria and major outcome measures were used by the authors. The reliability of major outcome events was reported poorly or not at all and in two studies outcome measures were clinically inappropriate. The studies scored 30-62% of the maximum attainable score for internal validity and 10-20% for external validity. CONCLUSION: The effectiveness of antibiotic treatment in acute maxillary sinusitis in a general practice population is not based sufficiently on evidence.   相似文献   
8.
Peroxynitrite (PN), a nitric oxide (NO*)-derived anion, has been associated with NO* damage in various cell types. We examined the effects of adding PN to cultured human osteoblast-like (hOB) cells obtained after hip arthroplasty. Exposure to PN (0.1-0.4 mM) decreased both hOB proliferation and differentiation, measured by [3H]thymidine uptake and alkaline phosphatase production, respectively. Incubation with 3-morpholinosydnonimine (SIN-1; 0.25-1 mM), an NO* and O2- donor that leads to PN release, also reduced both hOB proliferation and differentiation. Coincubation with both superoxide dismutase (SOD; 100 U/ml) and catalase (CAT; 50 U/ml), rendering SIN-1 a pure NO* donor, reversed its effects on hOB proliferation and differentiation. However, SIN-1-induced NO* production, measured by nitrite release to the hOB medium, was not altered by cotreatment with SOD and CAT. Expression of nitrotyrosine by hOB, a marker of PN action, was significantly increased after SIN-1 addition, as compared with untreated cells, as revealed by Western blot analysis. Interleukin-1alpha (IL-1alpha) and interferon gamma (IFN-gamma) but not tumor necrosis factor alpha (TNF-alpha) also significantly increased nitrotyrosine expression in these cells. These data show that PN is at least partially responsible for osteoblast derangement by NO* and that cytokines released during inflammatory arthropathies can induce PN production in hOB cells.  相似文献   
9.
Co-existence of facial and occipital pain may occur in occipital neuralgia, migraine and cluster headache; suggesting convergence of trigeminal and cervical afferents. Such convergence has been shown in humans and other animals, but the site and extent of this are uncertain. In anaesthetized adult cats, the superior sagittal sinus and occipital nerve were stimulated electrically, and extracellular recordings made in the dorsolateral area of the upper cervical cord using glass-coated tungsten electrodes. Of 49 units in 10 cats, 33 (67%) had input from the superior sagittal sinus and the occipital nerve. Thirteen (27%) had superior sagittal sinus input and 3 (6%) had occipital nerve input. Convergent receptive fields were identified mechanically in 7 units. These experiments in cats show convergent input from occipital nerve and superior sagittal sinus on dorsolateral area units in two-thirds of cases studied. This experimental site of trigeminocervical convergence may relate to referral of pain in occipital neuralgia and other headaches.  相似文献   
10.
In patients with PG-dependent renal function, NSAID administration constantly reduces GFR and RBF in a dose-dependent fashion. In this situation, the risk of overt acute renal failure is high and should be taken into proper account. In contrast, the incidence of NSAID-related renal structural alterations appears to be very low, yet the absolute number of patients may be significant considering the wide use of such drugs. Concerning the antiproteinuric effect of NSAIDs, the unfavourable ratio risk/benefit does not seem to support their indication in proteinuric nephropathies. The development of PGHS-2 selective inhibitors is promising, and may open new therapeutical strategies in the treatment of the progression of renal disease.   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