全文获取类型
收费全文 | 10405篇 |
免费 | 502篇 |
国内免费 | 35篇 |
专业分类
耳鼻咽喉 | 175篇 |
儿科学 | 224篇 |
妇产科学 | 184篇 |
基础医学 | 1748篇 |
口腔科学 | 227篇 |
临床医学 | 838篇 |
内科学 | 2056篇 |
皮肤病学 | 183篇 |
神经病学 | 1037篇 |
特种医学 | 653篇 |
外国民族医学 | 1篇 |
外科学 | 1259篇 |
综合类 | 73篇 |
预防医学 | 429篇 |
眼科学 | 254篇 |
药学 | 999篇 |
中国医学 | 64篇 |
肿瘤学 | 538篇 |
出版年
2022年 | 56篇 |
2021年 | 136篇 |
2020年 | 87篇 |
2019年 | 113篇 |
2018年 | 146篇 |
2017年 | 125篇 |
2016年 | 168篇 |
2015年 | 226篇 |
2014年 | 289篇 |
2013年 | 395篇 |
2012年 | 545篇 |
2011年 | 596篇 |
2010年 | 349篇 |
2009年 | 360篇 |
2008年 | 607篇 |
2007年 | 660篇 |
2006年 | 614篇 |
2005年 | 634篇 |
2004年 | 629篇 |
2003年 | 612篇 |
2002年 | 597篇 |
2001年 | 132篇 |
2000年 | 115篇 |
1999年 | 141篇 |
1998年 | 139篇 |
1997年 | 127篇 |
1996年 | 101篇 |
1995年 | 87篇 |
1994年 | 90篇 |
1993年 | 100篇 |
1992年 | 82篇 |
1991年 | 65篇 |
1990年 | 58篇 |
1989年 | 80篇 |
1988年 | 61篇 |
1987年 | 62篇 |
1986年 | 47篇 |
1985年 | 69篇 |
1984年 | 60篇 |
1983年 | 57篇 |
1982年 | 59篇 |
1981年 | 68篇 |
1980年 | 48篇 |
1979年 | 52篇 |
1978年 | 45篇 |
1977年 | 62篇 |
1976年 | 44篇 |
1975年 | 45篇 |
1973年 | 35篇 |
1963年 | 34篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Determination of Dissolved Oxygen in Heterogenous Systems Particularly in Emulsions and Oily Liquids
Foiβner Karl-Heinz Leonhardt Andreas Wegner Gerhard Heinz Bauer Kurt 《Pharmaceutical research》1985,2(1):44-46
The content of dissolved oxygen was determined by four independent methods in a series of non-aqueous or heterogenous systems. The Lex-O2-Content Analyzer represents a fast and simple apparatus that employs a coulometric oxygen assay with Hersch cell detection. A comparison of the results with different methods demonstrates the reliability of the Lex-O2 in the determination of oxygen dissolved in heterogeneous or non-aqueous systems. Therefore, this apparatus can be recommended for the measurement of oxygen in oxygenator or perfusion fluids, as well as in blood substitutes or other oxygen transporting systems. 相似文献
52.
Early biochemical and morphological changes of the rat adrenal medulla induced by xylitol 总被引:1,自引:0,他引:1
Long-term administration of high doses of xylitol and other polyols in rats has been associated with an increase in adrenal medullary hyperplasia and neoplasia. In order to exclude age-related factors and to differentiate between unspecific stress reactions and direct effects of the compound administered, a model was developed for quantifying early adrenomedullary responses. Male SD rats were fed xylitol (10% or 20% in the diet) for 2 and 8 weeks, and early biochemical changes were correlated with a stereological analysis of the adrenal medulla. At first, the in vivo rate of catecholamine (CA) biosynthesis was slightly decreased (at 2 weeks). This was followed by an increase in dopamine--hydroxylase (DBH) activity (at 8 weeks). By that time, the total chromaffin cell volume had increased and the number of chromaffin cells per reference volume had decreased in a dose-dependent way. The total number of chromaffin cells per adrenal gland showed a distinct tendency towards an increase. Adrenal epinephrine and norepinephrine contents were not altered, and both tyrosine hydroxylase and phenylethanolamine-N-methyltransferase activities remained unchanged. These data suggest that continued xylitol administration evoked an inhibitory effect on CA synthesis that, together with stimulation of the adrenal medulla brought about by the compound, resulted in compensatory medullary hypertrophy and hyperplasia. 相似文献
53.
K Richter W E Hempel W Gerhard K Vogelreuter C U Wagenknecht 《Zeitschrift für die gesamte innere Medizin und ihre Grenzgebiete》1986,41(15):413-418
With the help of an approx. 280 000 inhabitants check of x-ray-morphological suspects of a heart disease the laboratory parameters thymol turbidity test, zinc-sulphate turbidity test, total protein, serum protein electrophoresis and the enzymes "ASAT" and "ALAT" in longitudinal section and cross-section were examined in an intervention study during 5 years. All these parameters show standard values on the average, but compared to a healthy reference they showed significant differences, which relations to heart and vessel diseases could be deduced from. This referred especially to age-inverse behaviour of the transaminases only concerning male test persons. The examination of the longitudinal section confirmed exactly the results of the cross-section analysis. On the one hand it underlines the results got from the cross-section and in the second place it contributes to the efficient diagnostics by learning undone a repetition of these laboratory examinations during the period of 5 years with such a defined population. The relations of the particularities mentioned obviously refer to subclinical fields. Effects of therapy do not reflect in the laboratory findings. 相似文献
54.
ACE inhibition reduces activity of the plasminogen/plasmin and MMP systems in the brain of spontaneous hypertensive stroke-prone rats 总被引:2,自引:0,他引:2
Liebetrau M Burggraf D Wunderlich N Jäger G Linz W Hamann GF 《Neuroscience letters》2005,376(3):205-209
The spontaneously hypertensive stroke-prone rat (SHR-SP) is an experimental model of malignant hypertension which lead to secondary alterations of the extracellular matrix. Our aim was to determine ACE-inhibitor related changes of proteases involved in the reconstruction of the extracellular matrix in the brain. Twelve SHR-SP rats were randomized into two groups. Each group was treated with either an antihypertensive dose of ramipril or placebo for 6 months. Brain tissue plasminogen activator (t-PA) and urokinase (u-PA) were quantified by using casein-dependent plasminogen zymography, matrix metalloproteinase (MMP)-2 and MMP-9, by MMP-zymography, and tissue inhibitor of MMP (TIMP)-1 and -2, by reverse zymography. The amounts of u-PA, t-PA, and MMPs were significantly reduced in animals treated with ACE inhibitor. Plasminogen zymography showed a 39% reduction of u-PA in the basal ganglia (p < 0.0001); t-PA expression was reduced by 26% in the cortex and by 33% in the basal ganglia (p < 0.0001). MMP-2 expression was reduced by 15% in the cortex (p < 0.05) and by 10% in the basal ganglia (p < 0.05); MMP-9 expression significantly decreased by 37% in the cortex and by 25% in the basal ganglia (p < 0.0001 each). No differences were observed in the amount of TIMP-1 or TIMP-2. These findings provide new insights into the biochemical mechanisms underlying extracellular matrix proliferation and its modulation by ACE inhibitors. Therapeutic alterations that influence the proteolytic systems might prove important in the prevention of extracellular matrix accumulation and secondary microvascular vessel wall changes. 相似文献
55.
56.
Endoscopic cordectomy. a proposal for a classification by the Working Committee, European Laryngological Society 总被引:6,自引:0,他引:6
M. Remacle Hans E. Eckel Antonio Antonelli Daniel Brasnu Dominique Chevalier Gerhard Friedrich Jan Olofsson Heinrich H. Rudert Walter Thumfart Marco de Vincentiis Thomas P. U. Wustrow 《European archives of oto-rhino-laryngology》2000,257(4):227-231
The European Laryngological Society is proposing a classification of different laryngeal endoscopic cordectomies in order
to ensure better definitions of postoperative results. We chose to keep the word “cordectomy” even for partial resections
because it is the term most often used in the surgical literature. The classification comprises eight types of cordectomies:
a subepithelial cordectomy (type I), which is resection of the epithelium; a subligamental cordectomy (type II), which is
a resection of the epithelium, Reinke’s space and vocal ligament; transmuscular cordectomy (type III), which proceeds through
the vocalis muscle; total cordectomy (type IV); extended cordectomy, which encompasses the contralateral vocal fold and the
anterior commissure (type Va); extended cordectomy, which includes the arytenoid (type Vb); extended cordectomy, which encompasses
the subglottis (type Vc); and extended cordectomy, which includes the ventricle (type Vd). Indications for performing those
cordectomies may vary from surgeon to surgeon. The operations are classified according to the surgical approach used and the
degree of resection in order to facilitate use of the classification in daily practice. Each surgical procedure ensures that
a specimen is available for histopathological examination.
Received: 29 December 1998 / Accepted: 2 July 1999 相似文献
57.
Andreas Obruca Karl Mock Wilfried Feichtinger Gerhard Lunglmayr 《Journal of assisted reproduction and genetics》1995,12(9):627-631
Purpose
Intracytoplasmic injection (ICSI) with testicular sperm was performed in 16 couples. All men had ductal obstruction and failed previous attempts of epididymal sperm microaspiration.Methods
Testis tissue was obtained by excisional biopsies and incubated in HEPES buffered EBSS medium over 24 h at 37C. Motile sperm (Grade 1 to 2) were recovered in 13 patients and fertilized a total of 62 oozytes. Four pregnancies were achieved.Results
One healthy boy and two girls (twin pregnancy) were born.Conclusions
The ongoing pregnancies revealed no fetal abnormalities on ultrasound scanning.Presented at the IXth World Congress on In Vitro Fertilization and Alternate Assisted Reproduction, April 3–7, 1995, Vienna, Austria. 相似文献
58.
Rainer Netzer Pascal Pflimlin Gerhard Trube 《Pflügers Archiv : European journal of physiology》1994,426(3-4):206-213
The barium current through voltage-dependent calcium channels was recorded from cultured rat cortical neurons with the whole-cell configuration of the patch-clamp technique. The maximal current evoked by depolarising pulses from –80 mV to 0 mV was divided into inactivating and non-inactivating fractions. During the first minutes of whole-cell recording, the amplitude of the inactivating fraction increased from less than 0.1 nA to an average value of 1 nA, whereas the amplitude of the non-inactivating component remained essentially the same. This increase in amplitude was prevented when the perforated-patch technique was used, suggesting that some intracellular factor that inhibited the barium current was lost or destroyed during conventional whole-cell experiments. When GTP[-S] or GTP was added to the pipette solution, no increase or only a weak rise of the inactivating current was seen, whereas GDP[-S] accelerated its increase. The results suggest that some of the calcium channels expressed in cultured cortical neurons are inhibited by a G protein even in the absence of added neurotransmitter. The current increase observed during whole-cell recordings may be due to a loss of intracellular GTP and the subsequent inactivation of an inhibitory G protein. 相似文献
59.
Exposure to wood preservatives containing pentachlorophenol (PCP) was detected in 65 women who consulted the Endocrinological Department of the University Hospital of Obstetrics and Gynecology, Heidelberg, Germany, because of gynecological problems. Blood PCP levels ranged from 20.7 to 133 microg per liter of serum. One hundred and six women with similar clinical conditions, corresponding age and body weight, no PCP exposure in history, and PCP levels below 20 microg per liter of serum served as control group. Significant associations were found between serum PCP concentrations, age, and different parameters of the endocrine system. PCP may act centrally on a hypothalamic or suprahypothalamic level which may result in mild ovarian and adrenal insufficiency. PCP may, therefore, play a role in the increasing infertility problem. 相似文献
60.
Given the changes of gender roles in this century it is hardly justified to assume constant proportions of alcohol consumption for males and females. The purpose of the study was to reconstruct the consumption trends of males and females in Switzerland since the beginning of the 20th century. Cirrhosis mortality and survey data were used to disaggregate by sex the per capita alcohol consumption based on liver cirrhosis mortality suggests that the evolution of alcohol consumption in Switzerland followed a parallel course for both sexes only until the 1930 s. The low consumption during World War II and the evident increase until the beginning of the '60s seem to have resulted above all from the variations in consumption of beer by men. The decrease in total alcohol consumption observed since the '70s is also most probably due only to men; there is no indication of a decreasing consumption by women. The tendency of male and female consumption patterns to become more similar should be taken into account in the prevention of alcohol misuse. 相似文献