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   578篇
  免费   17篇
  国内免费   5篇
耳鼻咽喉   2篇
儿科学   31篇
妇产科学   22篇
基础医学   59篇
口腔科学   11篇
临床医学   66篇
内科学   112篇
皮肤病学   58篇
神经病学   23篇
特种医学   25篇
外科学   75篇
综合类   27篇
预防医学   43篇
眼科学   7篇
药学   31篇
肿瘤学   8篇
  2022年   6篇
  2021年   4篇
  2017年   3篇
  2016年   4篇
  2015年   6篇
  2014年   6篇
  2013年   9篇
  2012年   5篇
  2011年   12篇
  2010年   13篇
  2009年   20篇
  2008年   9篇
  2007年   6篇
  2006年   6篇
  2005年   4篇
  2004年   7篇
  2003年   13篇
  2002年   6篇
  2001年   15篇
  2000年   3篇
  1999年   7篇
  1998年   10篇
  1997年   19篇
  1996年   11篇
  1995年   10篇
  1994年   14篇
  1993年   4篇
  1992年   6篇
  1991年   4篇
  1989年   11篇
  1988年   11篇
  1986年   8篇
  1985年   6篇
  1984年   5篇
  1982年   6篇
  1981年   3篇
  1975年   3篇
  1974年   3篇
  1959年   18篇
  1958年   45篇
  1957年   45篇
  1956年   44篇
  1955年   50篇
  1954年   41篇
  1949年   4篇
  1948年   12篇
  1938年   3篇
  1935年   2篇
  1932年   2篇
  1927年   2篇
排序方式: 共有600条查询结果,搜索用时 15 毫秒
1.
Specific cutaneous lesions are a rare occurrence in myelodysplastic syndromes (MDS). The concurrent association of blistering skin lesions similar to those in bullous pemphigoid (BP), even though a rare event, suggests that BP may be a paraneoplastic syndrome. We report an 86-year-old man who had a refractory anaemia with excess bone marrow blasts in transformation, who developed a generalized pruritic blistering eruption. Immunohistopathological tests showed subepidermal blisters with linear deposits of IgG and C3 along the basement membrane zone of the epidermis surrounding a tumoral dermal infiltrate of CD13+ and CD15+ cells. Immunoblotting studies using epidermal extracts revealed circulating IgG antibodies against three protein bands: a 210–215 kDa band. a 180kDa band which co-migrated with the BP 180 antigen, and a 190kDa band. The tumour infiltrate may have revealed antigenic determinants which led to the onset of BP. The concept of paraneoplastic pemphigoid remains to be either confirmed or invalidated by further epidemiological studies.  相似文献   
2.
3.
4.
5.
The most commonly used photoaffinity labeling probes are compared, which are aryl azides, aryl diazirines, α-diazocarbonyls and benzophenone-derivatives. The compounds were used under identical conditions and crosslinking efficiency, influence of water, irradiation requirements, and by-products were investigated. Using the pentapeptide thymopentin (TP5) as a model system, we synthesized four analogues by solid-phase peptide synthesis and partially N-terminal modification to obtain [p-(3-trifluoromethyl)diazirinophenylalanine5] TP5, [p-benzoylphenylalanine5] TP5, 4-azidobenzoyl-TP5 and 2-diazo-3, 3, 3-trifluoropropionyl-TP5. The peptides were characterized by HPLC and ion-spray mass spectroscopy. Irradiation of the peptides with two different ultraviolet sources was carried out in water, n-propanol and water/n-propanol to imitate both hydrophobic and hydrophilic peptide/protein-interactions as well as the influence of the aqueous environment. Analysis of the products with HPLC, ion-spray MS, HPLC-MS and HPLC-CID-MS revealed that (Tmd)Phe is a highly potent carbene-precursor, which can be transformed easily into uniform crosslinking products by smooth photolysis. However, the electrophilic nature of the intermediate causes a high tendency to react with water molecules. The 4-azidobenzoyl group showed comparable crosslinking efficiency, but the probability to create non-uniform irradiation products (e.g. through rearrangement) is higher, whereas the reaction with water is less dominant. In contrast, Bpa was found to have an extremely low affinity to react with water, whereas prolonged UV irradiation is needed to get complete rearrangement into a variety of products. As the absorption band of α-diazocarbonyls at around 350 nm possesses a low extinction coefficient, 2-diazo-3, 3, 3-trifluoropropionyl-TP5 could not be activated at all with the optimized irradiation conditions that we have chosen for our comparative studies. © Munksgaard 1997.  相似文献   
6.
The effect of 5-nitro-6,7-dimethyl-1,4-dihydro-2,3-quinoxalinedione (ACEA-1328), a competitive and systemically bioavailable NMDA receptor/glycine site antagonist, was examined on opioid-induced antinociception in the tail flick test. Swiss Webster mice were injected with ACEA-1328 either alone or in combination with morphine or (±)-trans-U-50488 methanesulfonate (U50,488H), a μ- and a κ-opioid receptor agonist, respectively, and tested for antinociception. Systemic administration of ACEA-1328 alone increased the tail flick latencies with an ED50of approximately 45 mg kg−1. Concurrent administration of ACEA-1328 with morphine, or U50,488H, at doses that did not affect tail flick latencies, potentiated the antinociceptive effect of the opioid analgesics and vice versa. Naloxone, an opioid receptor antagonist, while not modifying the effect of ACEA-1328, did block the augmentation, suggesting that opioid receptors might be involved in the latter effect. 5-Aza-7-chloro-4-hydroxy-3-(m-phenoxyphenyl)quinoline-2(1H)-one (ACEA-0762), a selective NMDA receptor/glycine site antagonist, also showed enhancement of the antinociceptive effect of morphine and U50,488H. However, concurrent administration of 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline (NBQX), a selective non-NMDA receptor antagonist, with morphine did not alter the antinociceptive potency of the opioid analgesic. Overall, the data suggest that ACEA-1328 may increase the potency of the opioid analgesics by antagonising the glycine site associated with the NMDA receptor.  相似文献   
7.
The objective was to demonstrate bioequivalence between s.c. and i.m. administration of Humegon (FSH/LH ratio 1:1) and Normegon (FSH/LH ratio 3:1). In two randomized, single-centre, cross-over studies, 18 healthy volunteers on each formulation were assigned to one of the two administration sequences. Subjects were given single doses of one of the above gonadotrophins after endogenous gonadotrophin production had first been suppressed using high-dose oral contraceptive. Subsequently, rate (Cmax, tmax) and extent (AUC) of absorption of follicle stimulating hormone (FSH) and luteinizing hormone (LH) were determined for 14 days. For Cmax and AUC, analysis of variance (ANOVA) was performed on log-transformed data and for tmax ANOVA was performed on ranks. Intramuscular and s.c. injections of Humegon were bioequivalent with respect to the main pharmacokinetic parameters, being AUC and Cmax of FSH absorption. Intramuscular and s.c. injections of Normegon were bioequivalent with respect to the AUC of FSH and not bioequivalent with respect to the Cmax of FSH. For tmax of FSH as well as for most LH variables of both preparations, bioequivalence could not be proven due to the high intra- and interindividual variability and/or concentrations being close to the detection limit. Thus, the main pharmacokinetic FSH variables after i.m. and s.c. administration of Humegon and Normegon were bioequivalent.   相似文献   
8.
Nifedipine and alpha1-adrenergic blockade in Raynaud's phenomenon   总被引:1,自引:0,他引:1  
The efficacy of nifedipine and prazosin in the treatment ofRaynaud's phenomenon was assessed in a prospective double-blindrandomized cross-over trial in 15 patients. Each patient receivedone week of nifedipine 20 mg TID, one week of prazosin 1 mgTID, and 2 weeks of placebo. Nifedipine was shown to be effectivein reducing both the frequency and the severity of Raynaud'sphenomenon, whereas prazosin was ineffective. Before initiationof therapy in the 15 patients, pressor responses to the intravenousalpha1-agonist phenylephrine were assessed in the basal state,30 min after 20 mg oral nifedipine, and 30 min after 1 mg oralprazosin; the shift to the right of the log dose-vasopressorresponse curves to phenylephrine was similar with nifedipineand prazosin.  相似文献   
9.
The objectives of this study are: (a) to determine the occurrenceof permanent work disability (PWD) in early rheumatoid arthritis(RA); (b) to identify prognostic groups of patients; (c) toassess the employment rates for these groups over time. Seventy-threegainfully employed consecutive out-patients with early RA (  相似文献   
10.
传染性肺结核患者家庭中儿童结核感染发病及预防的研究   总被引:3,自引:1,他引:3  
目的 分析传染性肺结核患者家庭中的儿童结核感染和发病情况 ,探讨预防儿童发病的有效方案。方法 对与传染性肺结核患者密切接触的儿童进行X线胸透和做结核菌素试验 ;对结核菌素强阳性者给予预防性治疗。结果 与传染性肺结核患者密切接触的儿童感染率为 88 2 %。规则预防治疗组、不规则预防治疗组和不接受预防治疗组的患病率分别为 :8 3%、4 7 6 %、5 8 8%。结论 与传染性肺结核患者密切接触的儿童属于高危人群 ,给予预防性治疗可减少发病。  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