全文获取类型
收费全文 | 6046篇 |
免费 | 354篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 82篇 |
儿科学 | 136篇 |
妇产科学 | 186篇 |
基础医学 | 789篇 |
口腔科学 | 85篇 |
临床医学 | 508篇 |
内科学 | 1254篇 |
皮肤病学 | 290篇 |
神经病学 | 415篇 |
特种医学 | 394篇 |
外国民族医学 | 1篇 |
外科学 | 1015篇 |
综合类 | 92篇 |
一般理论 | 8篇 |
预防医学 | 307篇 |
眼科学 | 152篇 |
药学 | 377篇 |
中国医学 | 4篇 |
肿瘤学 | 332篇 |
出版年
2021年 | 63篇 |
2020年 | 52篇 |
2019年 | 51篇 |
2018年 | 66篇 |
2017年 | 64篇 |
2016年 | 99篇 |
2015年 | 130篇 |
2014年 | 180篇 |
2013年 | 228篇 |
2012年 | 259篇 |
2011年 | 261篇 |
2010年 | 191篇 |
2009年 | 176篇 |
2008年 | 200篇 |
2007年 | 253篇 |
2006年 | 238篇 |
2005年 | 235篇 |
2004年 | 206篇 |
2003年 | 215篇 |
2002年 | 205篇 |
2001年 | 199篇 |
2000年 | 212篇 |
1999年 | 174篇 |
1998年 | 128篇 |
1997年 | 103篇 |
1996年 | 77篇 |
1995年 | 73篇 |
1994年 | 74篇 |
1993年 | 70篇 |
1992年 | 100篇 |
1991年 | 96篇 |
1990年 | 133篇 |
1989年 | 125篇 |
1988年 | 77篇 |
1987年 | 89篇 |
1986年 | 77篇 |
1985年 | 67篇 |
1984年 | 65篇 |
1983年 | 60篇 |
1982年 | 42篇 |
1980年 | 50篇 |
1979年 | 69篇 |
1978年 | 41篇 |
1977年 | 46篇 |
1976年 | 46篇 |
1975年 | 69篇 |
1974年 | 47篇 |
1973年 | 63篇 |
1972年 | 44篇 |
1970年 | 44篇 |
排序方式: 共有6427条查询结果,搜索用时 15 毫秒
51.
Besides the methods of screwing of plates and medullary nailing, the fixateur externe (F.E.) is another method which can be considered for treating bone fractures at the femur, F.E. being an exceptional indication. In fresh fractures of the femur, open fractures of the second and third grade as well as debris and multiple-plane fractures are typical indications for F.E. Over and above, F.E. is almost always indicated as an emergency measure in case of initial inoperability (polytrauma, shock, loss of blood, craniocerebral trauma) or continuing general inoperability. F.E. has been found useful to an even greater extent especially in old fractures, refractures, pseudarthroses and infected pseudarthroses. Combined treatment of the infected pseudarthroses with F.E. and Septopal balls has proved particularly effective. The special advantages of F.E. application at the femur are blood-saving surgery requiring relatively little time and technical equipment, avoidance of surgically conditioned infection risk in the fractured region, avoidance of additional denudation of free fracture fragments, long-term applicability, good external stabilization with selective possibility between compression, distraction and neutral positioning of the fractured area, postoperative treatment without dressing, and free access to the fractured area without interfering with the F.E.; furthermore, exchangeability of the F.E., possibility of correcting the position and axis without surgical intervention, non-fixation of the adjacent joints and maintenance of physiotherapeutic treatment possibilities. F.E. is "panacea" and should not be applied without exact knowledge of the static and mechanical and biomechanical conditions and effects. Before resorting to F.E. this must be carefully weighed against the use of internal osteosynthesis methods. It is not a rival method to plate screwing and medullary nailing but rather an auxiliary system whenever these methods are inapplicable or would entail disadvantages. 相似文献
52.
H. Hofmann O. Schmut 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》1977,204(4):281-285
Zusammenfassung Aus Rinderglaskörper wurde pepsin-lösliches Kollagen isoliert, das bei der Untersuchung mit der Disk-Elektrophorese eine -Komponente zeigte, die im 1-Bereich wanderte. Auffallend sind mehrere Farblinien zwischen der - und der -Komponente. Bei der Disk-Elektrophorese der Bromcyan-Peptide von pepsin-löslichem Glaskörperkollagen kann festgestellt werden, daß das Peptidmuster nicht mit dem identisch ist, das aus pepsin-löslichem Typ II Kollagen erhalten werden kann.
Comparison of the cyanogen bromide peptides of vitreous body collagen and type II collagen
Summary Pepsin-soluble collagen was isolated from bovine vitreous humor. This collagen showed only one -chain in disc electrophoresis, migrating in the 1-chain position and between the - and -components some colored bands were visible. The disc electrophoretic patterns of the cyanogen bromide peptides of pepsinsoluble vitreous body collagen and pepsin-soluble type II collagen revealed no identity.相似文献
53.
Selective neuronal survival and upregulation of PCNA in the rat inner retina following transient ischemia 总被引:1,自引:0,他引:1
Ju WK Kim KY Hofmann HD Kim IB Lee MY Oh SJ Chun MH 《Journal of neuropathology and experimental neurology》2000,59(3):241-250
In this study we investigated the extent and time course of neuronal cell death and the regulation of the proliferating cell nuclear antigen (PCNA) in the different retinal cell layers following ischemia-reperfusion injury. Retinal ischemia was induced by controlled elevation of the intraocular pressure for a duration of 60 min. Changes in thickness and cell numbers in the retinal cell layers were analyzed at various time points (1 h to 4 weeks) after reperfusion. In parallel, apoptotic cell death was determined by the TUNEL method and the expression of PCNA analyzed by immunocytochemistry. In addition, we tested whether PCNA is expressed in neurons by double immunocytochemistry. The reduction in thickness was found to be less pronounced in the inner nuclear layer (INL). Correspondingly, cell numbers decreased by only 33% in the inner retina, but by more than 80% in the outer nuclear layer (ONL). Alterations in glial cell numbers did not contribute significantly to postischemic changes in the INL and ONL as assessed by using immunocytochemical markers for microglial and Müller cells. The time course of cell death determined by the TUNEL technique also differed markedly in the retinal layers being rapid and transient in the inner retina but delayed and prolonged in the ONL. PCNA immunoreactivity was undetectable in the normal retina, but was specifically induced in neurons of the inner retina within 1 h after reperfusion and was sustained for at least 4 weeks. We conclude that in contrast to photoreceptors in the ONL, a significant proportion of inner retinal neurons is resistant to ischemic insult induced by transiently increased intraocular pressure and that PCNA may possibly play a role in the selective postischemic survival of these cells. 相似文献
54.
Johnston-Wilson NL Sims CD Hofmann JP Anderson L Shore AD Torrey EF Yolken RH 《Molecular psychiatry》2000,5(2):142-149
Severe psychiatric disorders such as schizophrenia, bipolar disorder and major depressive disorder are brain diseases of unknown origin. No biological marker has been documented at the pathological, cellular, or molecular level, suggesting that a number of complex but subtle changes underlie these illnesses. We have used proteomic technology to survey postmortem tissue to identify changes linked to the various diseases. Proteomics uses two-dimensional gel electrophoresis and mass spectrometric sequencing of proteins to allow the comparison of subsets of expressed proteins among a large number of samples. This form of analysis was combined with a multivariate statistical model to study changes in protein levels in 89 frontal cortices obtained postmortem from individuals with schizophrenia, bipolar disorder, major depressive disorder, and non-psychiatric controls. We identified eight protein species that display disease-specific alterations in level in the frontal cortex. Six show decreases compared with the non-psychiatric controls for one or more diseases. Four of these are forms of glial fibrillary acidic protein (GFAP), one is dihydropyrimidinase-related protein 2, and the sixth is ubiquinone cytochrome c reductase core protein 1. Two spots, carbonic anhydrase 1 and fructose biphosphate aldolase C, show increase in one or more diseases compared to controls. Proteomic analysis may identify novel pathogenic mechanisms of human neuropsychiatric diseases. 相似文献
55.
Matic G Hofmann D Winkler R Tiess M Michelsen A Schneidewind JM Hebestreit G Keysser M Müller W Kinze EM Ramlow W 《Artificial organs》2000,24(2):103-107
Elimination of IgG can be achieved by extracorporeal immunoadsorption (IA) based on specific binding to either staphylococcal protein A (Excorim) or sheep polyclonal antibodies directed against human IgG (Therasorb). In 602 analyzed sessions of IA, elimination of IgG was 60% through 80% depending on the treated plasma volume, with no significant difference between the mentioned systems. However, the decrease of IgM and IgA was approximately 50% in the anti-IgG compared to 20-40% in the protein A system. Plasma albumin concentration decreased by 20% in the anti-IgG system compared to 15% in the protein A system, and hemoglobin values increased by 2% in the anti-IgG system and decreased by 6% in the protein A system. In conclusion, a clinical relevance for these findings cannot be ruled out, and the individual choice might depend on the clinical situation and laboratory findings. 相似文献
56.
Martins K Ahrenholz P Matic GB Hofmann D Tiess M Winkler RE Ramlow W 《Artificial organs》2000,24(7):526-532
Release of microparticles into the blood during extracorporeal circulation must be kept low because of possibly serious acute and chronic adverse effects. Concentration and size distribution of microparticles were measured during simulated treatments (n = 7) on original equipment for 2 standard low-density lipoprotein (LDL) elimination procedures (DALI 750, Fresenius AG, St. Wendel, Germany and Liposorber, Kaneka Corporation, Osaka, Japan) and compared to hemofiltration solutions. For both systems as well as in hemofiltration solutions, the mean particle concentrations in 500 ml portions gathered from the efferent blood line stayed below 10% of pharmacopoeia standards for infusion solutions (United States Pharmacopoeia, European Pharmacopoeia) in all measured size classes. Although particle concentrations were comparable in all systems, the mean total number of particles > or =2 microm released per session was lowest in the DALI (167,000) compared to the Liposorber (465,000) and hemofiltration solutions (2,240,000). This was mainly due to different total processed blood volumes necessary to achieve the required LDL reduction. 相似文献
57.
Diagnostic imaging in femur head necrosis 总被引:9,自引:0,他引:9
Diagnosis of avascular necrosis (AVN) of the hip has been improved by the technical progress of imaging modalities during the last decade. For a long period, only plain radiographs had been available. Scintigraphy and computed tomography contributed to differential diagnosis and early detection of bone necrosis. In the meantime, MR imaging has gained special value in the evaluation of AVN. It is now the method of choice for early detection as well as for assessment in later stage disorders. Using the ARCO system, all imaging modalities and their diagnostic viability are described. Findings regarding the different stages of AVN are correlated to tissue-specific changes. 相似文献
58.
A study was carried out to find out the effects of prior physical activity, sports participation and prior military training on the incidence of stress fractures among Gentlemen Cadets (GC''s) undergoing military training at Indian Military Academy (IMA). One thousand and fourteen GC''s were followed up for a period of 12 weeks. Thirty-seven GC''s developed stress fractures during the study period. The incidence of stress fractures was significantly higher in GC''s without any prior military training (p=0.0009). They were compared with 100 healthy controls drawn from the study population to study the influence of the other mentioned factors. There was no significant association between prior physical activity and stress fractures (OR=0.74, 95% CL=0.26 to 2.05, p=0.688). There was also no significant relationship between sports participation and stress fractures (OR=0.79. 95% CCL=0.35 to 1.81, p=0.684).KEY WORDS: Risk factors, Stress fractures 相似文献
59.
Differential regulation of ciliary neurotrophic factor and its receptor in the rat hippocampus following transient global ischemia 总被引:3,自引:0,他引:3
To investigate a potential role of ciliary neurotrophic factor (CNTF) in transient global ischemia, we have studied the postischemic regulatory changes in the expression of CNTF and its receptor, the ligand-binding alpha-subunit (CNTFRalpha). Immunoblot analysis demonstrated CNTF levels were slightly upregulated already during the first day after ischemia and then increased markedly by more than 10-fold until 2 weeks postischemia. Immunoreactivity for CNTF became detectable 1 day after ischemia and was localized in reactive astrocytes. The intensity of the immunolabeling was maximal in CA1 during the phase of neuronal cell death (days 3-7 postischemia) and in the deafferented inner molecular layer of the dentate gyrus. Upregulation of CNTF expression was less pronounced in CA3 and absent in the stratum lacunosum moleculare and the outer molecular layer of the dentate gyrus and thus did not simply correlate with astroliosis as represented by upregulation of glial fibrillary acidic protein (GFAP). As shown by in situ hybridization, expression of CNTFRalpha mRNA was restricted to neurons of the pyramidal cell and granule cell layers in control animals. Following ischemia, reactive astrocytes, identified by double labeling with antibodies to GFAP, transiently expressed CNTFRalpha mRNA with a maximum around postischemic day 3. This astrocytic response was most pronounced in CA1 and in the hilar part of CA3. These results show that CNTF and its receptor are differentially regulated in activated astrocytes of the postischemic hippocampus, indicating that they are involved in the regulation of astrocytic responses and the neuronal reorganizations occurring after an ischemic insult. 相似文献
60.
Mäurer M Becker G Wagner R Woydt M Hofmann E Puls I Lindner A Krone A 《Acta neurochirurgica》2000,142(10):1089-1097
Summary ? Purpose. In this prospective study the results of multimodal postoperative neuro-imaging were related to the survival of patients
with high grade gliomas.
Methods. All 73 patients included underwent microsurgical tumour resection and had postoperative CT and transcranial sonography (TCS)
examinations. In addition, 35 of the 73 patients received an early postoperative MRI. Patients were followed up for at least
one year.
Findings. At the end of the 7 year study period 56 patients had died. The median survival time was 371 days. Survival rate was significantly
higher in patients with anaplastic astrocytomas and inpatients displaying complete tumour resection on MRI (log-rank-test,
p<0.05) or a small postoperative residual tumour bulk on TCS (log-rank-test, p<0.05). Cox proportional hazards model identified
histological tumour grade, postoperative Karnofsky index, complete resection based on MRI and small postoperative residual
tumour mass on TCS as independent predictors of survival.
Interpretation. This study demonstrates that early postoperative neuro-imaging has prognostic implications for the survival of patients with
high grade gliomas. According to our results postoperative imaging with MRI and TCS is a valuable prognostic with regard to
patient survival and should therefore be implemented in postoperative follow-up. It also helps to evaluate the efficacy of
adjuvant therapy. 相似文献