全文获取类型
收费全文 | 6311篇 |
免费 | 636篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 84篇 |
儿科学 | 185篇 |
妇产科学 | 148篇 |
基础医学 | 1021篇 |
口腔科学 | 109篇 |
临床医学 | 751篇 |
内科学 | 1417篇 |
皮肤病学 | 87篇 |
神经病学 | 538篇 |
特种医学 | 311篇 |
外国民族医学 | 1篇 |
外科学 | 809篇 |
综合类 | 178篇 |
一般理论 | 4篇 |
预防医学 | 592篇 |
眼科学 | 61篇 |
药学 | 371篇 |
中国医学 | 20篇 |
肿瘤学 | 298篇 |
出版年
2021年 | 108篇 |
2020年 | 65篇 |
2019年 | 92篇 |
2018年 | 88篇 |
2017年 | 87篇 |
2016年 | 98篇 |
2015年 | 111篇 |
2014年 | 138篇 |
2013年 | 225篇 |
2012年 | 265篇 |
2011年 | 267篇 |
2010年 | 166篇 |
2009年 | 168篇 |
2008年 | 260篇 |
2007年 | 274篇 |
2006年 | 277篇 |
2005年 | 268篇 |
2004年 | 264篇 |
2003年 | 236篇 |
2002年 | 208篇 |
2001年 | 218篇 |
2000年 | 198篇 |
1999年 | 196篇 |
1998年 | 124篇 |
1997年 | 98篇 |
1996年 | 90篇 |
1995年 | 75篇 |
1994年 | 68篇 |
1993年 | 70篇 |
1992年 | 156篇 |
1991年 | 138篇 |
1990年 | 133篇 |
1989年 | 156篇 |
1988年 | 140篇 |
1987年 | 133篇 |
1986年 | 117篇 |
1985年 | 99篇 |
1984年 | 87篇 |
1983年 | 72篇 |
1982年 | 58篇 |
1981年 | 52篇 |
1980年 | 57篇 |
1979年 | 76篇 |
1978年 | 37篇 |
1977年 | 41篇 |
1976年 | 42篇 |
1975年 | 44篇 |
1974年 | 41篇 |
1973年 | 54篇 |
1972年 | 41篇 |
排序方式: 共有6985条查询结果,搜索用时 12 毫秒
991.
992.
SÁNDOR HUSZ M.D. Ph .D I. TÓTH-KÁSA M.D. Ph .D M. KISS Ph .D. A. DOBOZY M.D. D.SC Ph .D 《International journal of dermatology》1994,33(3):210-213
Background. The etiology of cold contact urticaria is unknown and the therapy is therefore usually rather disappointing. Methods. This study reports therapeutic data on 42 patients with cold urticaria treated with a combination of terbutaline (3 × 5 mg a week, later 3 × 2.5 mg) and aminophylline-containing drugs (3 × 150 mg). Results. Complete remission of the urticarial response was achieved in 37 of the 42 patients. Conclusions. The therapy was tolerated relatively well and the results are promising. 相似文献
993.
994.
Steven Taylor M.SC. William J. Koch Ph.D. David J. Crockett Ph.D. 《Journal of anxiety disorders》1991,5(4)
The recent debates and commentaries about the construct validity of the Anxiety Sensitivity Index (ASI) suggest several issues that remain to be resolved. First, the factor structure of the ASI remains to be clarified. Second, the distinction between this instrument and measures of trait anxiety has yet to be elucidated. A third issue concerns the extent to which the ASI and the trait version of the State-Trait Anxiety Inventory (STAI-T) can discriminate between panic disorder and other anxiety disorders. These issues were investigated by administering the ASI and the STAI-T to 142 spider-phobic college students and 93 psychiatric outpatients. In both samples, the ASI was found to be unifactorial. When the pool of ASI and STAI-T items was subjected to a factor analysis with oblique rotation, both samples yielded a two-factor solution. The STAI-T items were responsible for almost all the salient loadings on the first factor, and the ASI items were responsible for almost all the salient loadings on the second factor. In both samples the correlation between the factors was .39. These results suggest that the ASI is not simply a measure of trait anxiety. Items that are particularly important in defining the ASI concern the fear of bodily sensations. Fear of the social consequences of anxiety played a minor role in this factor. Panic-disordered patients were differentiated from patients with other anxiety disorders by ASI items pertaining to fear and catastrophic misinterpretation of bodily sensations. The full-scale score and item responses of the STAI-T were unable to differentiate between the anxiety groups. The findings support the construct validity of the ASI and the recent cognitive models of panic disorder. The results also suggest that a three-item version of the ASI may be used for the diagnosis of panic disorder. 相似文献
995.
A quality management approach to optimizing delivery and administration of preoperative antibiotics.
L Welch A C Teague B A Knight A Kenney J E Hernandez 《Clinical performance and quality health care》1998,6(4):168-171
OBJECTIVE: To optimize the process for delivering and administering preoperative antibiotics in order to prevent potential adverse patient outcomes. DESIGN: Using a multidisciplinary quality-improvement team, an evaluation of the preoperative medication order and delivery process was conducted. Charts were reviewed by selected time periods, with winter 1994 discharges for orthopedic surgeries (n = 97) and spring 1995 discharges for open heart procedures (n = 50) being used to arrive at baseline data (n = 147). A plan was devised to mainstream the medication-use process so that it would be standardized hospitalwide. A goal of administering preoperative antibiotics within 30 to 60 minutes prior to cut time was established. Following redesign and education, a repeat chart review of orthopedic surgeries (n = 33) and open heart procedures (n = 168) was conducted during April 1997 for discharges from the same diagnosis-related groups to total (n = 201). SETTING: A nearly 1,000-bed tertiary referral center and teaching hospital with three separate campuses. RESULTS: We identified multiple ordering mechanisms, multiple medication sources and delivery sites, multiple administration sites and administering personnel, and other logistical conflicts. Thirty-one percent of cases received antibiotics less than 30 minutes prior to start time, 39% between 30 to 60 minutes, and 30% greater than 60 minutes before start time. Following the multidisciplinary redesign and education, an increase from 39% to 61% receiving preoperative antibiotics between 30 to 60 minutes prior to surgery start time and a decrease from 31% to 18% receiving them in less than 30 minutes was documented. The percentage of patients receiving preoperative antibiotics in 60 minutes or less increased from 70% to 80%. CONCLUSION: A continuous quality-improvement approach that engages all departments involved in patient care is necessary to achieve meaningful change in complicated hospital processes. 相似文献
996.
P G Knight A J Beard J H Wrathall R J Castillo 《Journal of molecular endocrinology》1989,2(3):189-200
Analysis of bovine follicular fluid (FF) using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) coupled with a sensitive immunoblotting procedure resolved several components that were immunoreactive with an antiserum directed against the n-terminus of the alpha subunit of human inhibin (hI alpha(1-32]. Under non-reducing conditions, three intensely stained bands having apparent Mr values of 116,000, 44,000 and 25,000 were present, whilst under reducing conditions only two intensely stained bands (Mr 43,000 and 21,000) were detected. The Mr 44,000 and 25,000 immunoreactive forms (non-reducing conditions) were also demonstrated in bovine utero-ovarian vein and peripheral venous plasma after subjecting samples (40 ml) to immunoaffinity concentration using Sepharose beads coupled to anti-hI alpha(1-32), SDS-PAGE and immunoblotting. The same approach revealed the presence of the smaller (Mr 25,000) form in bovine granulosa cell-conditioned culture medium (GCCM). Gel-permeation chromatography (Sephacryl S-200), immunoaffinity chromatography (Sepharose-anti-hI alpha(1-32] and reversed-phase high-performance liquid chromatography (RP-HPLC; C18 and C8 columns) were employed to isolate from bFF (30 ml, 19.5 g protein) 750 micrograms protein which appeared essentially homogeneous by RP-HPLC and SDS-PAGE and had an Mr of 25,000 (non-reducing conditions)/21,000 (reducing conditions), identical to that of the immunoreactive component of lowest Mr found in bovine FF, utero-ovarian vein plasma, peripheral plasma and GCCM. The isolated material was highly immunoreactive with antisera against both hI alpha(1-32) and purified Mr 32,000 bovine inhibin but was devoid of biological activity when tested in a rat pituitary cell inhibin bioassay. Amino-terminal analysis revealed an amino acid sequence (residues 1-14) identical to that reported elsewhere for the alpha subunit (Mr 20,000/21,000) of bovine inhibin. In conclusion, the present study has revealed that the bovine ovary secretes considerable quantities of monomeric inhibin alpha subunit. The unexpected presence of this material in peripheral blood is likely to hinder attempts to obtain physiologically relevant data on circulating levels of inhibin in cattle using conventional radioimmunoassays. 相似文献
997.
Factors involved in salvaging ischaemic rabbit skin flaps: ATP and free radicals but not thromboxane
K R Knight E Dvir H Kawabata S A Coe A M Macleod B M O'Brien 《British journal of plastic surgery》1989,42(6):675-681
Rabbit epigastric free flaps were subjected to ischaemia at 25 degrees C for 24 hours. At the time of revascularisation the flaps were infused intra-arterially with one of the following: Hanks balanced salt solution (control), the high energy phosphates PEP/ATP, the thromboxane synthetase inhibitor dazoxiben hydrochloride, the free radical scavenger SOD and a combination of all these agents (treated groups). Control ischaemic flap survival at post-ischaemia day 7 was 23.5%, while the other treatments resulted in improved flap survival of 43.5% (p less than 0.025), 23.5% (not significant), 38.6% (p less than 0.05) and 35.7% (p less than 0.05) respectively. None of these agents improved post-ischaemic blood flow significantly. These results would support the use of PEP/ATP or SOD in the clinical treatment of failing ischaemic skin flaps but do not support the use of dazoxiben hydrochloride. 相似文献
998.
Keratin composition has been widely used as a biochemical marker of differentiation in normal epithelia, cell culture systems and tumours of epithelial tissues. We have been developing a model system for the study of human squamous epithelial cell differentiation, and among a panel of monoclonal antibodies we have generated for analysing this system are two antibodies recognizing subsets of epidermal keratins. The two antibodies, designated LICR-LON-16a and LICR-LON-29b, were raised to the human squamous carcinoma cell line LICR-LON-HN-5, and we describe here their biochemical and immunocytochemical characterization. Antibody 16a reacts with only epidermal basal cells in normal human skin and shows specificity for the 45 and 46 kdalton keratins. Antibody 29b stains all living layers of the epidermis, and reacts with a broad range of ketain polypeptides, (45-56 kdaltons) in immunoblotting analyses. We have investigated the alterations of cellular staining that occur in chronic hyperproliferative skin diseases and carcinomas and compared this with the staining of multilayered cultures of normal keratinocytes and the HN-5 cell line. We show that in squamous cell carcinomas and in HN-5 cell xenografts 16a and 29b stain only the well-differentiated cell types. Furthermore we found that the basal cell specificity of 16a was lost in all of the hyperproliferative skin lesions examined including psoriasis and eczema. This transition to suprabasal staining pattern was also seen in the cultures of normal keratinocytes and HN-5 cells. We conclude that aberrant keratin synthesis or abnormal post-translational processing of keratins associated with an increased rate of cell turnover could account for the altered expression of the epitope recognized by antibody 16a. 相似文献
999.
The cranial circulation, both extracerebral and cerebral, is innervated by fibers from the trigeminal nerve. This system is known as the trigeminovascular system. The large venous sinuses and dura mater are pain-sensitive and are innervated primarily by branches of the ophthalmic division of the trigeminal nerve. Studies were conducted in the α-chloralose anaesthetised cat to examine bulk carotid and cerebral blood flow responses to electrical stimulation of the trigeminal ganglion and superior sagittal sinus. Bulk carotid blood flow was measured using an ultrasonic flow probe and meter applied to the common carotid artery while cerebral blood flow was measured using laser Doppler flowmetry. Vascular resistance was calculated using simultaneously collected blood pressure data. Stimulation of the trigeminal ganglion resulted in a frequency-dependent reduction in both bulk carotid and cerebral vascular resistance. The mean maximal reduction was 39±5% at 20/s for the carotid bed and 37±6% at 20/s for the cerebral circulation. Stimulation of the superior sagittal sinus resulted in a frequency-dependent reduction in resistance that involved the cerebral circulation with little effect on bulk carotid resistance. The mean maximum reduction was 37±6% at 20/s for the cerebral circulation and 11±3% at 2/s for bulk carotid resistance. The more focused effects of superior sagittal sinus suggest a highly organised somatotopic arrangement of the trigeminal innervation of the cranial circulation. Such a physiological schema fits the known anatomy as reflected by the differential peptidergic innervation from the trigeminovascular system to cranial vessels and may be important in understanding the pathophysiology of migraine, cluster headache and subarachnoid haemorrhage. ©1997 Elsevier Science B.V. All rights reserved. 相似文献
1000.
Relation of deranged neonatal cerebral oxidative metabolism with neurodevelopmental outcome and head circumference at 4 years 总被引:3,自引:0,他引:3
SC Roth FRCR J. Baudin PhD E. Cady BSc K. Johal MBBS JP Townsend J S. Wyatt E O R. Reynolds FRS. FRCP A L. Stewart MRCPH 《Developmental medicine and child neurology》1997,39(11):718-725
Cerebral oxidative metabolism was studied using phosphorus magnetic resonance spectroscopy during the first week of life and neurodevelopmental outcome was assessed at 4 years in 62 infants who had clinical and/or biochemical evidence consistent with birth asphyxia (critically impaired intrapartum gas exchange). Twenty-one died and the neurodevelopmental status of the 41 who survived was assessed by a range of tests at age 4 years. The minimum recorded values for the cerebral phosphocreatine:inorganic phosphate concentration ratio (an index of oxidative metabolism) were related to outcome. The results showed significant relations between the extent of derangement of neonatal oxidative metabolism and a range of adverse outcomes, including death, and at 4 years reduced head growth and the presence and severity of neuromotor impairments, overall neurodevelopmental impairments, and cognitive functioning. Strong correlations between the extent of derangement of neonatal oxidative metabolism and outcome at 1 and 4 years were also shown. We conclude that the severities of adverse outcomes at 1 and 4 years of age were closely related to the extent of cerebral energy derangement in the first week of life, and we also conclude that primary intrapartum hypoxic-ischaemic cerebral injury was generally responsible for the events that led to death, microcephaly, and impaired 相似文献