全文获取类型
收费全文 | 26233篇 |
免费 | 1386篇 |
国内免费 | 183篇 |
专业分类
耳鼻咽喉 | 241篇 |
儿科学 | 585篇 |
妇产科学 | 408篇 |
基础医学 | 3500篇 |
口腔科学 | 659篇 |
临床医学 | 2531篇 |
内科学 | 5773篇 |
皮肤病学 | 616篇 |
神经病学 | 3234篇 |
特种医学 | 1655篇 |
外科学 | 3804篇 |
综合类 | 157篇 |
一般理论 | 8篇 |
预防医学 | 860篇 |
眼科学 | 661篇 |
药学 | 1459篇 |
中国医学 | 22篇 |
肿瘤学 | 1629篇 |
出版年
2023年 | 179篇 |
2022年 | 401篇 |
2021年 | 672篇 |
2020年 | 420篇 |
2019年 | 532篇 |
2018年 | 642篇 |
2017年 | 556篇 |
2016年 | 689篇 |
2015年 | 798篇 |
2014年 | 1013篇 |
2013年 | 1197篇 |
2012年 | 1923篇 |
2011年 | 1898篇 |
2010年 | 1243篇 |
2009年 | 1128篇 |
2008年 | 1720篇 |
2007年 | 1894篇 |
2006年 | 1657篇 |
2005年 | 1660篇 |
2004年 | 1572篇 |
2003年 | 1500篇 |
2002年 | 1346篇 |
2001年 | 228篇 |
2000年 | 163篇 |
1999年 | 213篇 |
1998年 | 255篇 |
1997年 | 212篇 |
1996年 | 161篇 |
1995年 | 119篇 |
1994年 | 125篇 |
1993年 | 110篇 |
1992年 | 81篇 |
1991年 | 68篇 |
1990年 | 53篇 |
1989年 | 62篇 |
1988年 | 68篇 |
1987年 | 43篇 |
1986年 | 40篇 |
1985年 | 40篇 |
1984年 | 31篇 |
1983年 | 48篇 |
1982年 | 37篇 |
1981年 | 36篇 |
1980年 | 39篇 |
1979年 | 29篇 |
1978年 | 39篇 |
1977年 | 26篇 |
1935年 | 27篇 |
1931年 | 28篇 |
1930年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
E. Valic Thomas Waldhör Christoph Konnaris Albert Michitsch Christian Wolf 《International archives of occupational and environmental health》1997,70(6):403-406
Hypothesis: Does occupational exposure to solvents in combination with alcohol intake give rise to acquired color vision defects? Method: A total of 138 individuals exposed to solvents (toluene, xylene, trichloroethylene, tetrachloroethylene) were examined using Lanthony’s D-15 test and compared with 100 nonexposed controls. The extent of color vision loss was quantitatively assessed based on Bowman’s color confusion index (CCI). A cumulative exposure index was calculated from the hours of exposure per day and the years of exposure. In 30 persons who were exposed to trichloroethylene and tetrachloroethylene, urinary trichloroacetic acid was assessed as a parameter of exposure. Alcohol intake was calculated as based on interviews of patients in grams of ethyl alcohol per week. Results: Individuals who consumed more than 250 g alcohol/week and were simultaneously exposed to solvents showed a significantly elevated CCI (P = 0.0044). No significant correlation emerged between trichloroacetid acid excretion in the urine or the cumulative exposure index and the CCI. Conclusion: The combination of alcohol intake and occupational exposure to solvents discloses the risk of acquired subclinical color vision defects. 相似文献
42.
Christoph Scherfler MD Johannes Schwarz MD PhD Angelo Antonini MD PhD Donald Grosset MD Francesc Valldeoriola MD PhD Kenneth Marek MD Wolfgang Oertel MD Eduardo Tolosa MD PhD Andrew J. Lees MD Werner Poewe MD 《Movement disorders》2007,22(9):1229-1238
The diagnosis of idiopathic Parkinson's disease (PD) can be achieved with high degrees of accuracy in cases with full expression of classical clinical features. However, diagnostic uncertainty remains in early disease with subtle or ambiguous signs. Functional imaging has been suggested to increase the diagnostic yield in parkinsonian syndromes with uncertain clinical classification. Loss of striatal dopamine nerve terminal function, a hallmark of neurodegenerative Parkinsonism, is strongly related to decreases of dopamine transporter (DAT) density, which can be measured by single photon emission computed tomography (SPECT). The use of DAT‐SPECT facilitates the differential diagnosis in patients with isolated tremor symptoms not fulfilling PD or essential tremor criteria, drug‐induced, psychogenic and vascular Parkinsonism as well as dementia when associated with Parkinsonism. This review addresses the value of DAT‐SPECT in early differential diagnosis, and its potential as a screening tool for subjects at risk of developing PD as well as issues around the assessment of disease progression. © 2007 Movement Disorder Society 相似文献
43.
Josef Georg Heckmann Tamara Fischer Ruben Maida Juan Carlos Jesus Galeote 《Zeitschrift fur Gesundheitswissenschaften》1998,6(2):166-177
The Chiquitano-tribe lives in the southern Amazonas region in Bolivia, remote from larger towns. A study (n=1514) on morbidity over an one year period (April 1995 till March 1996) and its relation to general and social medicine is given. Most frequently, childreh under 15 years and women in parity age (15–45 years) sought consultation (34,1 %, 42,7 %). Gastrointestinal, respiratoral and gynecological-obstetric diseases were predominant (22,4 %, 16,2 % and 15,7 %). In the dry season, common colds and respiratoral infections represented the major health problem. In the rainy season, infectious diarrhea diseases caused by polluted water as a consequence of extended floods were most frequent. Typical tropical diseases (malaria, Dengue fever, Chagas’ disease, leprosy a.o.) and socially caused diseases (AIDS, dependencies on drugs and alcohol, consequencies of crime) were rarely seen. With respect to severity, 55,8 % of the patients showed mild disorders. More serious diseases were observed in 39, 8 %. 4,6 % of the patients were diagnosed severly ill and needed hospitalization. Epidemiological data on general and social medicine of minorities in developing countries and their actual degree of medical care are important in a shrinking world. The data are useful to estimate medical needs and plan improvements to the health care system especially in rural areas. 相似文献
44.
Yu L. Liu Stephen J. Riederer Phillip J. Rossman Roger C. Grim Josef P. Debbins Richard L. Ehman 《Magnetic resonance in medicine》1993,30(4):507-511
A technique is described that provides improved reproducibility of breath-holding for MR image acquisition by monitoring the superior-inferior (S/I) position of the diaphragm. The method incorporates detection of the level of inspiration using an MR signal, rapid display to the patient of diaphragm position to enable breath-hold adjustment, and triggering of image data acquisition once appropriate position is attained. The response time of the system is short, approximately 10 ms. Studies in six volunteers using this method demonstrate a considerable decrease in the S/I range of diaphragm position over 10 consecutive periods of suspended respiration. The mean range is 1.3 mm with the system, while it is 8.3 mm without using it is expected that this method will be of assistance in many abdominal and cardiothoracic studies that use breath-hold techniques. 相似文献
45.
Prognostic value of somatosensory- and motor-evoked potentials in patients with a non-traumatic coma
Josef Zentner Alois Ebner 《European archives of psychiatry and clinical neuroscience》1988,237(3):184-187
Summary A total of 28 patients with non-traumatic coma were studied both with somatosensory- and motor-evoked potentials. While somatosensory-evoked potentials (SEP) have proved to be useful in predicting the outcome in patients with severe brain damage, the aim of this study was to find out whether the additional evaluation of motor-evoked potentials (MEP) could contribute to a better prediction of the outcome than SEP alone. Our results clearly indicate that in terms of prognostic value, SEP are superior to MEP. Nine patients with bilaterally preserved MEP died, while all of the patients with bilaterally preserved SEP and a central conduction time 6.5 ms survived, with a Glasgow outcome score of 1 to 3. Therefore, we cannot recommend the inclusion of MEP in the prognostic evaluation of patients with non-traumatic coma. 相似文献
46.
Heinz Schurawitzki M.D. Paul C. Hajek Josef Kramer Florian Grabenwöger Walter Klepetko Anton Moritz 《Cardiovascular and interventional radiology》1989,12(1):10-13
In a radiologic search for embolized leaflets of Edwards-Duromedics bileaflet valves in 2 patients, the embolized fragments were localized in the iliac vessels using computed tomography. Sonography was successful in one case and standard X-ray films of the abdomen were negative in both cases.In vitro investigations with Björk-Shiley and Edwards-Duromedics leaflets suggested that standard X-ray films of the abdomen and pelvis should be considered as the first investigational technique. If negative, computed tomography of the lower abdomen should be done. 相似文献
47.
James Deschner Birgit Rath-Deschner Susanne Reimann Christoph Bourauel Werner Gtz Soeren Jepsen Andreas Jger 《Annals of anatomy》2007,189(4):326-328
Recent studies have revealed that dynamic biomechanical forces can exert antiinflammatory and antiproteolytic effects on fibrocartitage. Whether the effects of mechanical strain also involve stimulation of the insulin-like growth factor (IGF) system and, therefore, of growth and repair of fibrocartilage has yet to be determined. The objective of this in vitro study was to determine if continuous biophysical strain regulates the gene expression of IGF1, IGF2, IGF1 receptor (IGF1R), insulin receptor substrate (IRS1), and IGF-binding proteins (IGFBP) 3 and 5 in cells from the fibrocartilaginous disc of the temporomandibular joint (TMJ). Rat TMJ disc cells were subjected to continuous biophysical strain (3% and 20%) for 4 and 24 h. Subsequently, RNA was extracted and real-time PCR was performed using an iCycler iQ detection system to analyze the gene expression of the IGF system. The gene expression of IGF1, IGF2, IGF1R, IRS1, IGFBP3, and IGFBP5 was significantly (p < 0.05) inhibited when cells were subjected to continuous biophysical strain, as compared to control at both time points. High strain induced a stronger inhibition of these molecules as compared to strain of Low magnitude. In conclusion, continuous biophysical strain seems to downregulate the expression of the IGF system and may, therefore, reduce the potential of fibrocartilage for growth and repair. 相似文献
48.
The complement system (C) is one of the main humoral components of innate immunity. Three major tasks of C against invading pathogens are: (i) lysis of pathogens by the formation of the membrane attack complex (MAC); (ii) opsonization of pathogens with complement fragments to favor phagocytosis; and (iii) attraction of inflammatory cells by chemotaxis. Like other particles, HIV activates C and becomes opsonized. To escape complement-mediated lysis, HIV has adopted various properties, which include the acquisition of HIV-associated molecules (HAMs) belonging to the family of complement regulators, such as CD46, CD55, CD59, and the interaction with humoral regulatory factors like factor H (fH). Opsonized virus may bind to complement receptor positive cells to infect them more efficiently or to remain bound on the surface of such cells. In the latter case HIV can be transmitted to cells susceptible for infection. This review discusses several aspects of C-HIV interactions and provides a model for the dynamics of this process. 相似文献
49.
Dudel J Hallermann S Heckmann M 《Pflügers Archiv : European journal of physiology》2000,441(2-3):175-180
Quartz glass electrodes are superior to conventional glass electrodes for low-noise recording. They have better electrical characteristics and hydrophobic surfaces which resist creeping of salt solutions. We used oxy-hydrogen heating with program-controlled gas pressure to melt quartz glass capillaries. Usually, the relative wall thickness (the quotient of the outer and inner diameters do/di) of capillaries is, at best, maintained up to the electrode tip. If tips with thicker walls can be produced, coating and other surface treatments can be avoided. We found that programmed heating periods without pull allowed an fivefold increase of do/di in the tip region. Since do/di is inversely proportional to input capacity, the recording noise was minimized and became insignificant relative to amplifier and holder noise. A sample patch-clamp recording is shown. 相似文献
50.
Schramm C Huber S Protschka M Czochra P Burg J Schmitt E Lohse AW Galle PR Blessing M 《International immunology》2004,16(9):1241-1249