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   831篇
  免费   43篇
  国内免费   1篇
耳鼻咽喉   8篇
儿科学   23篇
妇产科学   71篇
基础医学   119篇
口腔科学   51篇
临床医学   160篇
内科学   103篇
皮肤病学   13篇
神经病学   89篇
特种医学   14篇
外科学   57篇
综合类   4篇
预防医学   64篇
眼科学   1篇
药学   37篇
肿瘤学   61篇
  2022年   8篇
  2021年   15篇
  2020年   4篇
  2019年   17篇
  2018年   11篇
  2017年   13篇
  2016年   11篇
  2015年   14篇
  2014年   24篇
  2013年   48篇
  2012年   44篇
  2011年   44篇
  2010年   25篇
  2009年   26篇
  2008年   49篇
  2007年   68篇
  2006年   57篇
  2005年   38篇
  2004年   50篇
  2003年   49篇
  2002年   37篇
  2001年   11篇
  2000年   11篇
  1999年   13篇
  1998年   20篇
  1997年   10篇
  1996年   7篇
  1995年   7篇
  1994年   9篇
  1993年   7篇
  1992年   7篇
  1991年   9篇
  1989年   3篇
  1987年   5篇
  1986年   10篇
  1985年   6篇
  1984年   5篇
  1983年   3篇
  1982年   7篇
  1981年   4篇
  1980年   9篇
  1979年   11篇
  1978年   9篇
  1977年   9篇
  1976年   5篇
  1975年   5篇
  1974年   3篇
  1973年   3篇
  1971年   2篇
  1970年   4篇
排序方式: 共有875条查询结果,搜索用时 163 毫秒
1.
We have studied the intratumor HER-2/neu heterogeneity in 78 consecutive and population-based primary invasive breast carcinomas. Within the invasive component, heterogeneity was detected in only 1 of 78 tumors. In 48 tumors (62%), we found both in situ and invasive components in analyzed tissue sections. Twelve of these 48 tumors had a difference of at least 2 arbitrary units in the in situ compared with the invasive part of the tumor with regard to the HER-2/neu status analyzed by HercepTest (immunohistochemistry). Eight of these 12 tumors were reanalyzed with fluorescent in situ hybridization and immunohistochemistry with and without a new Automated Cellular Imaging System. In this limited material, immunohistochemistry in combination with the Automated Cellular Imaging System seemed to have a better correlation with fluorescent in situ hybridization than immunostaining analyzed manually. In conclusion, HER-2/neu expression is not seldom heterogeneous in invasive compared with in situ components within a tumor. This finding should be considered in the choice of evaluation method. To avoid heterogeneity as a confounding factor in HER-2/neu analyses, detection methods such as immunohistochemistry and fluorescent in situ hybridization, which can provide evaluation in a preserved tissue architecture, should be used. Perhaps the intratumor HER-2/neu heterogeneity can explain some of the unexpected failures of trastuzumab therapy.  相似文献   
2.
Abstract: Background: The laryngeal mask airway (LMA) can be used in general anaesthesia without neuromuscular block. The laryngeal tube (LT) is a new airway device with similar airway features as LMA. LT is provided with a distal cuff to prevent regurgitation. In this study we compared the LMA and LT concerning patient and user aspects. Methods: Sixty patients with ASA (American Society of Anestesiologists) score 1–2 scheduled for minor surgery were randomized to be ventilated either through LMA or LT. After insertion, the number of insertion attempts, and “positioning” and “airway-assessment” was evaluated. The patients reported on “sore throat” after 30 and 60 minutes and the day after anaesthesia. Results: Gender and mean age were equal in both groups. The first insertion attempt was successful in 25 of 28 patients randomised to LMA and in 23 of 27 patients randomised to LT. LMA was evaluated to be easier in “positioning” whereas no difference in “sore throat” was reported. Conclusion: We found no difference between the LMA and the LT in terms user and patient friendliness and safety.  相似文献   
3.
The aim of this study was to examine whether esophageal dysphagia can be described as a handicap and to grade the severity of handicap as the discrepancy between the subject's own eating goals and his or her eating disability. The severity of the disability-goal-handicap (DGH) regarding dysphagia was expressed on a scale ranging from 0 to 48 points. Nineteen patients with dysphagia of differing causes were selected from a patient register at a laboratory for diagnostic procedures of the esophagus. The severity of handicap for the 19 patients was, on average, 33 points (range, 20–44). The DGH score correlated significantly with the patients' own evaluation of the severity of their dysphagia (p=0.008). The DGH scores did not differ markedly based on patient's sex, age, or cause of dysphagia. Patients who were operated upon because of dysphagia had significantly more points on the DGH scale prior to operation than patients who were not (p=0.001). Denial of dysphagia (N=18), concealment of dysphagia (N=18), and lack of confirmation by the patient's physician (N=15) were common but did not influence the severity of handicap as assessed by the DGH scale. It was shown that dysphagia affects all aspects of life as expressed by reduction in self-esteem (N=13), security (N=16), work capacity (N=8), exercise (N=7), and leisure time (N=6). Esophageal dysphagia may therefore be regarded as a handicap when assessed using the DGH code described in this study.  相似文献   
4.
The paraneoplastic autoantibody, collapsin response-mediator protein (CRMP)-5 immunoglobulin G (IgG), is specific for neuronal cytoplasmic CRMP-5, and is usually associated with small-cell lung carcinoma or thymoma. We report on details of a movement disorder that followed anti-B-cell therapy in a patient with lymphoma, and was accompanied by CRMP-5 IgG.  相似文献   
5.
Summary: Ethylene–propylene (EP) copolymerisations were performed with two sterically different metallocenes activated by methylaluminoxane (MAO) in an attempt to better understand the effect of catalyst structure on termination reactions and polymer microstructure. The metallocene precursors under investigation were rac‐dimethylsilylbis(2‐methyl‐4‐phenyl‐1‐indenyl)zirconium dichloride ( 1 ) and a more sterically hindered counterpart rac‐dimethylsilylbis(2‐isopropyl‐4‐[3,5‐dimethylphenyl]indenyl) zirconium dichloride ( 2 ). For both catalyst systems, the most common termination mechanism was chain transfer to aluminium. In addition, for polymer samples polymerised with 1 /MAO, chain growth was terminated by chain transfer to Zr metal in propylene‐rich polymerisations and by chain transfer to ethylene monomer in ethylene‐rich polymerisations. The steric hindrance of 2 was able to suppress the chain transfer to the ethylene monomer, and chain transfer to Zr metal was also found in the ethylene‐rich polymerisations. The greater steric hindrance of 2 also affected the EP copolymer microstructure: regioregularity in the propylene‐rich copolymers was greater and isotacticity less with 2 /MAO than with 1 /MAO.

The catalyst precursors used: rac‐dimethylsilylbis(2‐methyl‐4‐phenyl‐1‐indenyl)zirconium dichloride ( 1 ) and rac‐dimethylsilylbis(2‐isopropyl‐4‐[3,5‐dimethylphenyl]indenyl) zirconium dichloride ( 2 ).  相似文献   

6.
Using the agar dilution technique, 231 strains of Bacteroides fragilis, isolated during a 2-year period from human infections, were identified at subspecies level and were tested for susceptibility to 13 beta-lactam antibiotics. The penicillins were benzylpenicillin, ampicillin, carbenicillin, cloxacillin, and the recently described penicillin derivatives cyclacillin, ticarcillin, and PC-904. The following cephalosporin derivatives were tested: cephaloridine, cephalothin, cephalexin, cefamandole and cefuroxime. The cephamycin C derivative cefoxitin was also included in the study. Cefoxitin was the most effective drug tested since more than 80% of the strains were inhibited by 8 microgram/ml or less, and no strain had a minimal inhibitory concentration (MIC) of more than 64 microgram/ml. There was no marked difference in sensitivity among the subspecies with exception of subspecies vulgatus, which was slightly more sensitive to all antibiotics tested. The size of the inoculum was an important factor for obtaining reproducible results in the sensitivity tests. Increased inocula resulted in markedly higher MICs for cephaloridine and cefuroxime. Production of beta-lactamase was performed on all isolates by a chromogenic cephalosporin substrate and about 90% of the strains were found to be beta-lactamase producers.  相似文献   
7.
Charcot Foot   总被引:1,自引:0,他引:1  
Charcot foot in its original sense is equivalent to stage 4 of hereditary motor and sensory neuropathy (HMSN) which is known as Charcot-Marie-Tooth disease since 1886. This entity, which can be subdivided into 3 groups including subgroups, predominantly begins during childhood and progresses slowly. The first symptom, often unnoticed by the patient for a long period, is weakness of the intrinsic foot muscles with consecutive hammer-toe formation and mobile pes cavus. Progredient atrophy of the peroneal, extensor, tibialis posterior and finally triceps surae muscles leads to fixed pes cavus varus excavatus with severe varus deformity of the hindfoot, secondary varus position of the talus at the ankle level and subsequent arthrosis of the medial compartment. Permanent varus deformity of the ankle almost invariably leads to stress fractures of the malleoli because of repetitive microtrauma (stage 5 of HMSN). Early detection of the disease with nerve conduction studies at clinical suspicion allows tibialis posterior transfer, correctional osteotomy of the hindfoot or arthrodesis of Chopart's or Lisfranc's joint and can postpone or prevent the otherwise inevitable triple arthrodesis which has a less favorable long-term prognosis. At stage 4 (manifest Charcot foot) and stage 5 (neuropathic fracture of the ankle) a reorientating ankle arthrodesis is advocated, with additional subtalar pathology correctional double arthrodesis becomes necessary. In diabetic arthropathy of the ankle (Type IV according to Sanders and Frykberg), which is often referred to as "Charcot Ankle", tibiocalcanear arthrodesis is indicated. In case of supervening infection or extensive necrosis a modified Pirogoff amputation is carried out as a salvage procedure. Doubled periods of non weight-bearing, immobilization and brace protection of the ankle help to reduce the frequently observed implant failure in both forms of osteoarthropathy. In addition to stable implants retrograde calcaneotalotibial transfixation with a Steinmann pin may help to protect the achieved result despite prolonged bone consolidation.  相似文献   
8.
The objective of the present study was to assess the relationship between the amount of lactate accumulated during complete ischaemia and the ensuing changes in extra- and intracellular pH (pHe and pHi, respectively). The preischaemic plasma glucose concentration of anaesthetized rats was varied by administration of glucose or insulin, pHe was determined in neocortex with ion-sensitive microelectrodes, and tissue lactate and CO2 contents were measured, tissue CO2 tension being known from separate experiments. The experiments were carried out in both normocapnic [arterial CO2 tension (PaCO2) approximately 40 mm Hg] and hypercapnic (PaCO2 approximately 80 mm Hg) animals. Irrespective of the preischaemic CO2 tension, DeltapHe was linearly related to tissue lactate content. Depending on the preischaemic glucose concentration, DeltapHe varied from <0.4 to >1.4 units. The results thus fail to confirm previous results that the changes in pHe describe two plateau functions (DeltapHe approximately 0.5 and 1.1, respectively), with a transition zone at tissue lactate contents of 17 - 20 mmol kg-1. Changes in pHi given in this study are based on the assumption of a uniform intracellular space. The pHi changed from a normal value of approximately 7.0 to 6.5, 6.1 and 5.8 at tissue lactate contents of 10, 20 and 30 mmol kg-1. The intrinsic (non-bicarbonate) buffer capacity, derived from these figures, was 23 mmol kg-1 pH-1. Some differences in pH and in HCO3- concentration between extra- and intracellular fluids persisted in the ischaemic tissue. These differences were probably caused by a persisting membrane potential in the ischaemic cells.  相似文献   
9.
Method for Dissection of Mesenteric Metastases in Mid-gut Carcinoid Tumors   总被引:1,自引:0,他引:1  
With adequate medical management the midgut carcinoid tumor generally is an indolent malignancy associated with substantial life expectancy and appreciable life quality, even in the presence of liver metastases and significant tumor burden. Abdominal complications may occur in this entity of carcinoids owing to entrapment of intestines and encasement of mesenteric vessels by mesenteric metastases and associated marked mesenteric fibrosis. This may be the cause of abdominal pain, disabling diarrhea, weight loss to the extent of malnutrition, and eventually the risk of death with acute or chronic intestinal obstruction or intestinal gangrene. Operative removal of the mesentericointestinal lesion is often indicated to prevent or treat these complications but may be technically difficult when mesenteric metastases extend in the vicinity of major vessels in the mesenteric root. At laparotomy 56 patients with advanced midgut carcinoids underwent removal of the mesenteric tumor with a method for preserving the mesenteric vessels. This was feasible by mobilizing and releasing the right colon and mesenteric root from posterior adhesions, identifying the mesenteric artery below the pancreas, and free-dissecting this artery on the tumor capsule in the mobilized mesentery. Dissection was successful even with tumors initially judged inoperable unless tumor growth completely surrounded the mesenteric vessels or extended retroperitoneally. One patient was subjected to distal intestinal artery bypass. Symptom relief was been substantial and often of long duration after mesenteric tumor removal in patients who prior to surgery often had threatening intestinal ischemia. Patients with advanced midgut carcinoids may benefit markedly from dissectional removal of mesenteric tumors, which (conceivably better than conventional wedge resection) preserves the length of the remaining intestine.  相似文献   
10.
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