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   2790篇
  免费   82篇
  国内免费   21篇
耳鼻咽喉   133篇
儿科学   124篇
妇产科学   103篇
基础医学   185篇
口腔科学   185篇
临床医学   204篇
内科学   549篇
皮肤病学   22篇
神经病学   186篇
特种医学   111篇
外科学   607篇
综合类   37篇
一般理论   1篇
预防医学   66篇
眼科学   119篇
药学   110篇
中国医学   31篇
肿瘤学   120篇
  2023年   22篇
  2022年   34篇
  2021年   51篇
  2020年   42篇
  2019年   44篇
  2018年   59篇
  2017年   44篇
  2016年   62篇
  2015年   81篇
  2014年   87篇
  2013年   135篇
  2012年   209篇
  2011年   216篇
  2010年   139篇
  2009年   123篇
  2008年   192篇
  2007年   208篇
  2006年   205篇
  2005年   192篇
  2004年   200篇
  2003年   196篇
  2002年   120篇
  2001年   45篇
  2000年   31篇
  1999年   18篇
  1998年   14篇
  1997年   12篇
  1996年   13篇
  1995年   9篇
  1994年   8篇
  1993年   6篇
  1992年   4篇
  1991年   7篇
  1990年   10篇
  1989年   3篇
  1988年   2篇
  1987年   7篇
  1986年   3篇
  1985年   6篇
  1984年   11篇
  1983年   3篇
  1982年   2篇
  1977年   1篇
  1976年   1篇
  1975年   4篇
  1974年   4篇
  1973年   1篇
  1962年   1篇
  1961年   1篇
  1959年   1篇
排序方式: 共有2893条查询结果,搜索用时 15 毫秒
81.
European Archives of Oto-Rhino-Laryngology - The aim of this study is to explore the anatomy of the Vidian nerve to elucidate the appropriate surgical approach based on preoperative cone-beam...  相似文献   
82.
In this study, the psychological effects of single-dose corticosteroids administered to patients who had undergone rhinoplasty were assessed. A total of 30 rhinoplasty patients were included in the study and were randomly assigned to 1 of 2 groups. Preoperatively, patients completed the Bech Rafaelsen Mania Scale and the Beck Depression Inventory. Dexamethasone 10 mg was given intravenously just before surgery to the first group, but no medication was administered to the second group. On the first postoperative day, patients were seen again, and the Bech Rafaelsen Mania Scale and the Beck Depression Inventory were again completed. Periorbital edema and ecchymosis were graded, and psychological well-being was measured on a standard visual analog scale. All patients and physicians were blinded to treatment until the end of the study. Results show that administration of a single-dose of dexamethasone 10 mg caused neither euphoria nor depression. No significant differences were observed between steroid and control groups in terms of patients’ psychological well-being. With single-dose dexamethasone, periorbital edema was significantly reduced on the first 2 postoperative days, and upper eyelid ecchymosis was significantly decreased only on the first postoperative day. However, preoperative steroid administration had no influence on ecchymosis of the lower eyelid. The authors conclude that single-dose dexamethasone 10 mg can be used safely to reduce periorbital edema and ecchymosis in rhinoplasty patients.  相似文献   
83.
Tryptophan degradation along the kynurenine pathway is of central importance for the immune function. Toll‐like receptors (TLRs), representing the first line of immune defence against pathogens, are expressed in various cell types. The most abundant expression is found on monocytes, macrophages and dendritic cells. The aim of this study was to investigate whether stimulation with different TLR ligands induces the kynurenine pathway in human peripheral monocytes. Cell supernatants were analysed using a liquid chromatography/mass spectrometry to measure kynurenine, kynurenic acid (KYNA), quinolinic acid (QUIN) and tryptophan. Stimulation of TLR‐2, TLR‐3, TLR‐4, TLR‐7/8 and TLR‐9 was found to induce the production of kynurenine, but only stimulation of TLR‐3 increased levels of further downstream metabolites, such as KYNA and QUIN. Stimulation of TLR‐1, TLR‐5 and TLR‐6 did not induce the kynurenine pathway. Taken together, this study provides novel evidence demonstrating that TLR activation induces a pattern of downstream tryptophan degradation along the kynurenine pathway in monocytes. The results of this study may implicate that TLRs can be used as new drug targets for the regulation of aberrant tryptophan metabolism along this pathway, a potential therapeutic strategy that may be of importance in several disorders.  相似文献   
84.
Purpose To investigate the effects of hyperbaric oxygen (HBO) treatment on renal functions and damage in septic rats.Methods The animals were divided into four groups, each containing ten animals: control, hyperbaric oxygen, sepsis, and sepsis/hyperbaric oxygen. One milliliter of saline containing live Escherichia coli cells (2.1 × 109) was injected intraperitoneally to induce sepsis. The groups treated with HBO were given five sessions of 2 atmospheres absolute of 100% oxygen at intervals of 6 h. Blood, urine, and tissue samples were then collected, and the functional renal parameters, malondialdehyde (MDA) levels, and superoxide dismutase (SOD) and catalase activities were examined.Results The reduced glomerular filtration rate and urine flow returned to normal levels after HBO treatment; however, the increase in fractionated sodium excretion continued. The increased MDA levels in the renal cortex and medulla also decreased to the level of the control group. In the sepsis group, both the SOD and catalase activities decreased in the renal cortex, while a reduction was observed only in the catalase activity in the medulla. The reduced enzyme activities significantly increased in the sepsis/hyperbaric oxygen group.Conclusion HBO treatment has a beneficial effect on renal dysfunction in sepsis. The probable reason for this effect is the reduction in oxidative damage because of the increase in antioxidative capacity.  相似文献   
85.
Dens invaginatus is a rare developmental malformation of teeth showing a deep infolding of enamel and dentine which may extend deep into the root. To date, conventional root canal therapy, endodontic surgery and extraction have been reported as treatment modalities, when the pulpo-dentinal complex of such teeth is affected. In the present report, non-surgical endodontic treatment of three maxillary lateral incisors with invaginatus (DI) is discussed. The Tri Auto ZX rotary system was used for shaping the root canals of two affected teeth and the Profile system was used in the third. Teeth with periradicular lesions received calcium hydroxide as an interim therapy. Two teeth were obturated with gutta percha points and AH Plus sealer using cold lateral compaction. In the third case, obturation was accomplished using a coated carrier system (Thermafil) due to the specific shape of the root canal system. Twelve months postoperatively all teeth were asymptomatic with resolution of the periapical radiolucency on two affected teeth, as confirmed radiographically. Healing was achieved without any need for further surgical intervention.  相似文献   
86.
Pulmonary arteriovenous malformation (AVM) is a rare vascular malformation of the lung that carries a considerable risk of serious complications such as cerebral embolism, brain abscess, and pulmonary hemorrhage. Embolization with coils or detachable balloons is currently the preferred treatment. Paradoxical embolization of coils and balloons may occur, especially in patients with large feeding arteries. This report describes an initial experience with the use of the Amplatzer Vascular Plug used for endovascular treatment of bilateral multiple pulmonary AVMs in an adult patient.  相似文献   
87.
To assess the ability to detect coronary artery narrowings from computer-acquired angiograms, a panel of 4 observers independently identified and measured focal coronary narrowings from digital subtraction angiograms and compared the results to those obtained from standard 35-mm cine film angiograms. Both cine and digital angiograms were obtained sequentially using selective intracoronary artery injection of standard amounts of iodinated contrast media. Digital images were obtained at 8 frames/s with a 512 × 512 × 8-bit pixel matrix. Modifications in the imaging chain for computer acquisition included a slower pulsed radiographic mode, a progressive scan camera, and initial storage of the images on an 80-megabyte digital hard disk. Postprocessing computer algorithms were used to enhance the unsubtracted digital images; these included single-frame, mask-mode subtraction, vessel boundary edge enhancement, and 4-fold pixel magnification. In 19 patient studies, 32 arteries were reduced more than 25 % in diameter according to at least 1 of 4 observers on either the digital or cine film angiograms. There was no significant difference in the mean percent diameter narrowing for all the narrowings between the digital angiograms (53 ± 31 %) and the cineangiograms (52 ± 31 %). In addition, a 2-way analysis of variance yielded no significant difference between the amount of variability in the measurements between the cine film and the digital technique. This similar variability persisted when subsets of patients based on the degrees of stenosis were considered (e.g., only narrowings from 50 to 90% diameter reduction). Because digital acquisition permits immediate playback with image enhancement and greater ease of coronary artery quantification, digital angiography may have widespread clinical use for the detection and quantitation of coronary artery disease.  相似文献   
88.
We report the case of a 38-year-old man with a long-standing history of a small ventricular septal defect presented with chest pain. Electrocardiography revealed sinus rhythm, ST-segment elevation in leads V1–6. The chest X-ray showed mild cardiomegaly. He underwent cardiac catheterisation laboratory to primary coronary angioplasty. Coronary angiography showed normal coronary arteries. Aortic root angiography revealed type A aortic dissection. Transthoracic and transesophageal echocardiography showed aortic dissection in ascending aorta and a perimembranous ventricular septal defect. Thoracoabdominal CT angiography confirmed the aortic dissection before the surgery.The patient underwent cardiac surgery immediately. The ventricular septal defect and aortic dissection were repaired successfully. The postoperative recovery was uneventful and he has thus far remained asymptomatic at 6 months' follow-up.  相似文献   
89.
CmeABC functions as a multidrug efflux pump contributing to the resistance of Campylobacter to a broad range of antimicrobials. In this study, we examined the role of CmeABC in bile resistance and its contribution to the adaptation of Campylobacter jejuni in the intestinal tract of the chicken, a natural host and a major reservoir for Campylobacter. Inactivation of cmeABC drastically decreased the resistance of Campylobacter to various bile salts. Addition of choleate (2 mM) in culture medium impaired the in vitro growth of the cmeABC mutants but had no effect on the growth of the wild-type strain. Bile concentration varied in the duodenum, jejunum, and cecum of chicken intestine, and the inhibitory effect of the intestinal extracts on the in vitro growth of Campylobacter was well correlated with the total bile concentration in the individual sections of chicken intestine. When inoculated into chickens, the wild-type strain colonized the birds as early as day 2 postinoculation with a density as high as 10(7) CFU/g of feces. In contrast, the cmeABC mutants failed to colonize any of the inoculated chickens throughout the study. The minimum infective dose for the cmeABC mutant was at least 2.6 x 10(4)-fold higher than that of the wild-type strain. Complementation of the cmeABC mutants with a wild-type cmeABC allele in trans fully restored the in vitro growth in bile-containing media and the in vivo colonization to the levels of the wild-type strain. Immunoblotting analysis indicated that CmeABC is expressed and immunogenic in chickens experimentally infected with C. jejuni. Together, these findings provide compelling evidence that CmeABC, by mediating resistance to bile salts in the intestinal tract, is required for successful colonization of C. jejuni in chickens. Inhibition of CmeABC function may not only control antibiotic resistance but also prevent the in vivo colonization of pathogenic Campylobacter.  相似文献   
90.
Orhan F  Sekerel BE 《Allergy》2003,58(2):127-131
BACKGROUND: Although beef allergy has long been considered a rare condition, the number of studies regarding the nature, epidemiology, and symptoms of beef allergy has been increasing. We aimed to describe the results of allergy work-up of 12 patients who have a convincing history of acute allergic symptoms following beef ingestion. METHODS: Detailed histories of 10 children and two adult relatives were obtained and patients underwent skin prick tests with commercial beef extract, raw beef and cooked beef. Serum total and beef-specific IgE were measured. Labial, and in selected cases, open food challenges were undertaken. RESULTS: Interestingly, the rate of family history of beef allergy was 67% (8/12). Three patients (two with commercial extract, and one with cooked beef) had positive skin test responses to beef. Ten (83%) patients had elevated serum IgE concentrations (median 316.5 kU/l, range 9-1321 kU/l) and the beef-specific IgE was positive in all patients (median 6.23 kUA/l, range 0.83-36.6 kUA/l). Labial food challenge was positive in four (30%) patients. Of the five patients who underwent open food challenges, three were positive and two tolerated the beef administered. CONCLUSIONS: We conclude that skin prick tests do not accurately diagnose IgE-mediated sensitization to beef. Thus, patients with suspected beef allergy should be screened additionally for beef-specific IgE antibodies, and in selected cases oral food challenge should be carried out to verify the diagnosis.  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