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   983篇
  免费   53篇
  国内免费   5篇
耳鼻咽喉   4篇
儿科学   21篇
妇产科学   22篇
基础医学   189篇
口腔科学   6篇
临床医学   56篇
内科学   198篇
皮肤病学   10篇
神经病学   62篇
特种医学   12篇
外科学   134篇
综合类   3篇
预防医学   14篇
眼科学   163篇
药学   90篇
肿瘤学   57篇
  2023年   5篇
  2022年   6篇
  2021年   17篇
  2020年   6篇
  2019年   10篇
  2018年   14篇
  2017年   14篇
  2016年   7篇
  2015年   10篇
  2014年   12篇
  2013年   29篇
  2012年   37篇
  2011年   35篇
  2010年   20篇
  2009年   11篇
  2008年   48篇
  2007年   41篇
  2006年   48篇
  2005年   45篇
  2004年   40篇
  2003年   48篇
  2002年   39篇
  2001年   45篇
  2000年   63篇
  1999年   35篇
  1998年   14篇
  1997年   10篇
  1996年   11篇
  1995年   9篇
  1994年   12篇
  1993年   6篇
  1992年   24篇
  1991年   22篇
  1990年   28篇
  1989年   28篇
  1988年   27篇
  1987年   15篇
  1986年   12篇
  1985年   20篇
  1984年   16篇
  1983年   14篇
  1982年   11篇
  1979年   5篇
  1975年   10篇
  1973年   5篇
  1972年   5篇
  1971年   10篇
  1969年   4篇
  1967年   6篇
  1966年   7篇
排序方式: 共有1041条查询结果,搜索用时 12 毫秒
71.
72.
A 78-year-old Japanese man with a 5-day history of fever (~38°C) and decreased appetite was admitted to our hospital. Transesophageal echocardiography revealed aortic valve vegetation. Streptococcus constellatus was detected from a blood culture. An antibiotic sensitive to this strain was administered for 6 weeks, and the patient has been well for 6 months without any sign of relapse. A review of all documented cases of infective endocarditis due to S. constellatus revealed nonspecific initial symptoms, especially coughing, and complications of abscess formation and septic embolisation. Clinicians should carefully consider the choice of antibiotic agents in the treatment of infective endocarditis due to S. constellatus, because penicillin-resistant strains have been documented in some cases.  相似文献   
73.
74.
PurposeLarge-scale protein analysis may bring important insights into molecular changes following branch retinal vein occlusion (BRVO). Using proteomic techniques this study compared aqueous humor samples from patients with BRVO to age-matched controls.MethodsAqueous humor samples from treatment naive patients with BRVO complicated by macular edema (n = 19) and age-matched controls (n = 18) were analyzed with label-free quantification nano liquid chromatography – tandem mass spectrometry (LFQ nLC-MS/MS). The severity of macular edema was measured as central retinal thickness (CRT) with optical coherence tomography. Control samples were obtained prior to cataract surgery. Proteins were filtered by requiring quantification in at least 50% of the samples in each group without imputation of missing values. Significantly changed proteins were identified with a permutation-based calculation with a false discovery rate at 0.05.ResultsIn BRVO, 52 proteins were differentially expressed. Regulated proteins were involved in cell adhesion, coagulation, and acute-phase response. Apolipoprotein C-III, complement C3, complement C5, complement factor H, fibronectin, and fibrinogen chains were increased in BRVO and correlated with CRT. Fibronectin also correlated with best corrected visual acuity (BCVA) and vascular endothelial growth factor (VEGF). Monocyte differentiation antigen CD14 (CD14) and lipopolysaccharide-binding protein (LBP) were upregulated in BRVO. Contactin-1 and alpha-enolase were downregulated in BRVO and correlated negatively with CRT.ConclusionsMultiple proteins, including complement factors, fibrinogen chains, and apolipoprotein C-III, correlated with CRT, indicating a multifactorial response. Fibronectin correlated with BCVA, CRT, and VEGF. Fibronectin may reflect the severity of BRVO. The proinflammatory proteins CD14 and LBP were upregulated in BRVO.  相似文献   
75.
Red-crowned cranes (Grus japonensis) are native to eastern Hokkaido (island population), in contrast to the mainland, which migrates between the Amur River basin and eastern China-Korea peninsula. During the 1990s we found that Red-crowned cranes in Hokkaido were highly contaminated with mercury: however, the source was unknown. We investigated the time trend of mercury contamination in Red-crowned cranes. Total mercury levels in the livers and kidneys from cranes dead in the 2000s were lower than those dead in the 1990s. Feather is a major pathway of mercury excretion for many bird species and is used as an indicator of blood mercury level during feather growth. As internal organs from the specimens collected before 1988 were not available, we analyzed the flight feather shavings from stuffed Red-crowned cranes dead in 1959-1987 and found that the mercury level of feathers from cranes dead in the 1960s and 1970s was not more than those from the cranes dead in the 2000s. These results suggest that mercury contamination in Red-crowned cranes in Hokkaido decreased temporally during the 1990s-2000s. This indicates the possible occurrence of some mercury pollution in Red-crowned cranes' habitat in this region in the 1990s or before.  相似文献   
76.
Surgery for refractory glaucoma   总被引:2,自引:0,他引:2  
Purpose: To determine the surgical outcome of mitomycin trabeculectomy in patients with refractory glaucoma.
Methods: Sixty-six eyes of 52 patients with refractory glaucoma underwent mitomycin trabeculectomy. Mitomycin was applied for five minutes only once during trabeculectomy. The follow-up period was six to 61 months.
Results: Cumulative success probability was calculated using Kaplan-Meier life-table analysis assuming the cut-off postoperative IOP to be 20 mmHg or IOP reduction by at least 20% in eyes with preoperative IOP 24mmHg. At the end of 61-month follow-up the success probability was 80%± 6% without postoperative ocular hypotensive medication (complete success) and was 95%± 3% regardless of postoperative antiglaucoma medication (overall success), respectively.
Conclusion: The data suggest that mitomycin trabeculectomy is efficacious in reducing IOP in patients with refractory glaucoma.  相似文献   
77.
The effect of co-administration of a mucolytic agent with a penetration enhancer was assessed on the intestinal absorption of poorly absorbed hydrophilic compounds. Fluorescein isothiocyanate-labeled dextran with average molecular weight of ca. 4.4 kDa (FD-4) was used as a model compound, and N-acetylcysteine (NAC) was used as a mucolytic agent. Sodium caprate (C10), tartaric acid (TA), sodium taurodeoxycholate (TDC), sodium dodecyl sulfate (SDS), p-t-octyl phenol polyoxyethylene-9.5 (Triton X-100, TX-100) were selected as penetration enhancers with different mechanisms of action. Various dosing solutions containing a penetration enhancer in the absence or in the presence of NAC were directly administered into the exposed rat jejunum, and the bioavailability of FD-4 up to 2 h was determined. The extent of improvement by co-administration was highly dependent on the penetration enhancer species applied. The observed enhancement was thought to result from the mucolytic activity of NAC, which can reduce the mucus viscosity and facilitate the penetration of FD-4 to mucosal membrane. Among the combinations tested, the simultaneous administration of NAC and TX-100 provided the highest enhancement (22.5-fold) of intestinal FD-4 absorption compared to the control. Although the detailed mechanism for the observed drastic improvement is unclear, one possible reason was thought to be due to the improved diffusivity of TX-100 micellar system in the mucus layer. All these results suggest that the combination of a mucolytic agent and a non-ionic surfactant may have potential as an enhancing system for peroral delivery of poorly absorbed hydrophilic compounds like protein and peptide drugs.  相似文献   
78.
5-Hydroxytryptamine (5-HT) receptor subtypes involved in 5-HT-induced contraction of the chicken gastrointestinal tract were characterized pharmacologically using subtype-selective agonists and antagonists. The proventriculus (area of stomach adjacent to the oesophagus) and ileum are examined. 5-HT applied cumulatively caused sustained contraction of the proventriculus that was not decreased by tetrodotoxin, atropine or l-nitro-arginine methylester (l-NAME). alpha-Methyl-5-HT showed the same potency as that of 5-HT, indicating the involvement of the 5-HT(2) receptor. (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-amino-propane (DOI), 5-methoxytryptamine and 1-(3-chlorophenyl)piperazine hydrochloride (mCPP) were potent, and 2-methyl-5-HT, 5-carboxamidotryptamine, BW723C86 and 6-chloro-2-(1-piperazinyl)pyrazine hydrochloride (MK212) were moderate, but (+/-)-8-hydroxy-2-dipropylaminotetralin hydrobromide (8-OH-DPAT), [endo-N-8-methyl-8-azabicyclo-(3,2,1)oct-3-yl]-2,3-dihydro-(1-methyl)ethyl-2-oxo-1H-benzimidazol-1-carboxamide (BIMU-8) and cisapride were weak agonists. Correlation of pEC(50) values of these agonists with documented pEC(50) values for 5-HT(2C) receptor was higher than 5-HT(2A) and 5-HT(2B). Cinanserin, ketanserin, methiothepin, methysergide, mianserin, (8-[5-(2,4-dimethoxy-5-(4-trifluoromethylphenylsulphonamido)phenyl-5-oxopentyl)-1,3,8-triazaspiro[4,5]decane-2,4-dione hydrochloride (RS102221), N-(1-methyl-1H-indolyl-5-yl)-N'-(3-methyl-5-isothiazolyl)urea (SB204741), spiperone and N-desmethylclozapine concentration-dependently inhibited the contractile responses to 5-HT. Correlation of pK(b)/pA(2) of antagonists with documented pK(i) for 5-HT(2C) receptor was highest among 5-HT(2) receptor subtypes. In the methysergide- and ketanserin-treated proventriculus, 5-HT, 2-methyl-5-HT and cisapride did not enhance the electrical field stimulation (5 Hz)-induced cholinergic contractions. 5-HT applied non-cumulatively caused transient contraction of ileum, and the responses were partly decreased by atropine or tetrodotoxin. 5-Methoxytryptamine, alpha-methyl-5-HT, 5-carboxamidotryptamine, L692,247 and DOI were potent agonists. However, 2-methyl-5-HT, cisapride, BW723C86, 8-OH-DPAT and 5-nonyloxytryptamine, mCPP and MK212 were less effective. Ketanserin and methysergide decreased the 5-HT-induced ileal contraction, but neither GR113808 nor SB269970 inhibited the responses. In conclusion, 5-HT causes contraction of the proventriculus via 5-HT(2C)-like receptors present on smooth muscle. 5-HT also causes contraction of the ileum, but the underlying mechanisms are complex, involving neural and smooth muscle components, and both 5-HT(1)- and 5-HT(2)-like receptors. Neural 5-HT receptors similar to 5-HT(3)/5-HT(4) receptors were not found in the chicken proventriculus and ileum.  相似文献   
79.
We report a rare case of traumatic spinal subarachnoid hematoma with Brown-Séquard syndrome following hyperextension injury. A 43-year-old man was admitted to our hospital four days after hyperextension cervical injury complaining of nuchal pain, left hemiparesis and dysesthesia of the left arm. On the third hospital day, neurological examination revealed left C2,3 level Brown-Séquard syndrome. High cervical plain CT scan showed a high density area in the left spinal canal from C1 vertebral body level to C2-3 intervertebral level. Emergency operation was performed and a left-sided subarachnoid hematoma was removed. The left C2 and C3 nerve roots were markedly stretched and the cord was shifted to the right. Neither vascular abnormality nor tumor was found and no traumatic change was seen on the cord. The Brown-Séquard syndrome disappeared soon after surgery, but the weakness of the left arm and anesthesia at the level of left C2 dermatome remained until six months after operation. Review of the literature revealed no such a case as the one in which the patient developed a spinal subarachnoid hematoma following hyperextension injury without any preexisting disease or injury of the spine. Brown-Séquard syndrome caused by spinal subarachnoid hematoma was not found on the literature either. So we believe that this is the first report of case of such lesion. The mechanism of subarachnoid clot formation on hyperextension injury may be due to transient dislocation of the spine with tearing of the anterior longitudinal ligament or to crushing of the cord between the ligamentum flavum, which bulged forward on hyperextension, and the posterior aspect of the vertebral body.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
80.
A 37-year-old housewife, who had physical characteristics of cerebral gigantism, such as the tall stature, acromegaly, macrocephalia, high arched palate and antimongoloid slant, developed cerebellar ataxia and dysarthria. Her mother, uncle and grandmother were also reported to have slowly progressive gait disturbance. Her mother was also tall. Endocrinological studies failed to show any definite abnormality. CT and MRI revealed remarkable cerebellar atrophy. Though cerebral gigantism is often associated with clumsiness and incoordination, the etiology of the ataxia is poorly understood. This case indicates that the ataxia in cerebral gigantism may be, at least partly, caused by cerebellar atrophy.  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