全文获取类型
收费全文 | 7304篇 |
免费 | 409篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 109篇 |
儿科学 | 260篇 |
妇产科学 | 172篇 |
基础医学 | 1123篇 |
口腔科学 | 109篇 |
临床医学 | 675篇 |
内科学 | 1319篇 |
皮肤病学 | 199篇 |
神经病学 | 661篇 |
特种医学 | 335篇 |
外科学 | 1148篇 |
综合类 | 30篇 |
一般理论 | 1篇 |
预防医学 | 524篇 |
眼科学 | 205篇 |
药学 | 441篇 |
中国医学 | 16篇 |
肿瘤学 | 405篇 |
出版年
2023年 | 46篇 |
2022年 | 80篇 |
2021年 | 141篇 |
2020年 | 95篇 |
2019年 | 142篇 |
2018年 | 167篇 |
2017年 | 116篇 |
2016年 | 170篇 |
2015年 | 160篇 |
2014年 | 227篇 |
2013年 | 270篇 |
2012年 | 449篇 |
2011年 | 439篇 |
2010年 | 257篇 |
2009年 | 241篇 |
2008年 | 371篇 |
2007年 | 367篇 |
2006年 | 388篇 |
2005年 | 429篇 |
2004年 | 360篇 |
2003年 | 342篇 |
2002年 | 345篇 |
2001年 | 163篇 |
2000年 | 130篇 |
1999年 | 152篇 |
1998年 | 98篇 |
1997年 | 78篇 |
1996年 | 63篇 |
1995年 | 68篇 |
1994年 | 50篇 |
1993年 | 51篇 |
1992年 | 89篇 |
1991年 | 70篇 |
1990年 | 90篇 |
1989年 | 71篇 |
1988年 | 66篇 |
1987年 | 56篇 |
1986年 | 47篇 |
1985年 | 74篇 |
1984年 | 41篇 |
1983年 | 45篇 |
1982年 | 50篇 |
1981年 | 28篇 |
1979年 | 48篇 |
1978年 | 28篇 |
1975年 | 33篇 |
1974年 | 32篇 |
1973年 | 36篇 |
1972年 | 34篇 |
1968年 | 27篇 |
排序方式: 共有7732条查询结果,搜索用时 0 毫秒
51.
Neugebauer E. Beckurts T. Lorenz W. Maroske D. Merte H. Horeyseck G. Dietz W. 《Inflammation research》1986,18(1-2):23-29
The hypothesis of a causal relationship between a progressive and unrestrained increase of tissue histamine formation by activation of an inducible histidine decarboxylase (HDC) and lethality in endotoxic shock (Schayer's induced histamine concept) was tested in a standardized rat endotoxic shock model.Initial enzyme identification studies in the rat shock liver (8 hrs after endotoxin challenge) clearly demonstrate that the induced histidine decarboxylase is an acid (specific) HDC. The succeeding randomized, controlled study with appropriate inhibitors of the enzyme, -methyl-histidine (competitive inhibitor) and -fluoromethyl-histidine (irreversible inhibitor) using doses of 2, 20 or 100 mg/kg showedno significant effect on the survival rate of rats in endotoxin shock. The survival rate of the non-treated endotoxin control group (NaCl) was 25%; all methylprednisolone treated rats (50 mg/kg) survived.Thus, the induced histamine isnot a predominant factor (necessary or sufficient determinant) for the lethal outcome in rat endotoxic shock. The protective effect of MP isnot predominantly due to the inhibition of the induced histidine decarboxylase. The use of HDC-inhibitors as the appropriate instruments for evaluation of the significance of this mechanism is discussed.Clinic of General Surgery, City Hospital Sieburg. 相似文献
52.
Ehling D Kennerknecht I Junge A Prager B Exeler R Behre B Horst J Schmitt-John T Bartsch O Wirth J 《American journal of medical genetics. Part A》2004,131(3):265-272
We describe two unrelated patients with cytogenetically visible deletions of 21q22.2-q22.3 and mild phenotypes. Both patients presented minor dysmorphic features including thin marfanoid build, facial asymmetry, downward-slanting palpebral fissures, depressed nasal bridge, small nose with bulbous tip, and mild mental retardation (MR). FISH and molecular studies indicated common deleted areas but different breakpoints. In patient 1, the breakpoint was fine mapped to a 5.2 kb interval between exon 5 and exon 8 of the ETS2 gene. The subtelomeric FISH probe was absent on one homologue 21 indicating a terminal deletion spanning approximately 7.9 Mb in size. In patient 2, the proximal breakpoint was determined to be 300-700 kb distal to ETS2, and the distal breakpoint 2.5-0.3 Mb from the 21q telomere, indicating an interstitial deletion sized approximately 4.7-7.3 Mb. The 21q- syndrome is rare and typically associated with a severe phenotype, but different outcomes depending on the size and location of the deleted area have been reported. Our data show that monosomy 21q of the area distal to the ETS2 gene, representing the terminal 7.9 Mb of 21q, may result in mild phenotypes comprising facial anomalies, thin marfanoid build, and mild MR, with or without signs of holoprosencephaly. 相似文献
53.
Ectopic bone formation associated with mesenchymal stem cells in a resorbable calcium deficient hydroxyapatite carrier 总被引:6,自引:0,他引:6
Kasten P Vogel J Luginbühl R Niemeyer P Tonak M Lorenz H Helbig L Weiss S Fellenberg J Leo A Simank HG Richter W 《Biomaterials》2005,26(29):5879-5889
Bone substitute materials can induce bone formation in combination with mesenchymal stem cells (MSC). The aim of the current study was to examine ectopic in vivo bone formation with and without MSC on a new resorbable ceramic, called calcium deficient hydroxyapatite (CDHA). Ceramic blocks characterized by a large surface (48 m2/g) were compared with beta-tricalcium phosphate (beta-TCP), hydroxyapatite (HA) ceramics (both ca. 0.5 m2/g surface) and demineralized bone matrix (DBM). Before implantation in the back of SCID mice carriers were freshly loaded with 2x10(5) expanded human MSC or loaded with cells and kept under osteogenic conditions for two weeks in vitro. Culture conditions were kept free of xenogenic supplements. Deposits of osteoid at the margins of ceramic pores occurred independent of osteogenic pre-induction, contained human cells, and appeared in 416 MSC/CDHA composites compared to 216 MSC/beta-TCP composites. ALP activity was significantly higher in samples with MSC versus empty controls (p<0.001). Furthermore, ALP was significantly (p<0.05) higher for all ceramics when compared to the DBM matrix. Compared to previous studies, overall bone formation appeared to be reduced possibly due to the strict human protocol. Ectopic bone formation in the novel biomaterial CDHA varied considerably with the cell pool and was at least equal to beta-TCP blocks. 相似文献
54.
Nowak-Göttl U Duering C Kempf-Bielack B Sträter R 《Pathophysiology of haemostasis and thrombosis》2003,33(5-6):269-274
Acquired and inherited prothrombotic risk factors increase the risk of thrombosis in neonates, infants and children. After suffering thrombosis white paediatric patients should be screened for common gene mutations, i.e. the factor V G1691A, factor II G20210A and MTHFR C677T genotypes, rare inherited prothromboticrisk factors, i.e. deficiencies of protein C,protein S, and antithrombin, plasminogen, probably inherited risk factors, i.e. fibrinogen, factor VIIIC, factor XII, new candidates, i.e. elevation of lipoprotein (a),and fasting homocysteine concentrations (3-6 months after thrombotic onset). Data interpretation is based on age-dependent reference ranges or the identification of causative gene mutations/polymorphisms with respect to individual ethnic backgrounds. 相似文献
55.
Warncke B Valtink M Weichel J Engelmann K Schäfer H 《Virchows Archiv : an international journal of pathology》2004,444(1):74-81
Transplantation of retinal pigment epithelial (RPE) cells is discussed as a possible therapeutic approach for retinal degeneration. Xenogeneic transplantation of human RPE cells in animal models has been studied extensively. Various methods have been used to identify the graft cells, but these methods interfere with cell behaviour so that the monitored physiological post-transplantation course may be influenced. In the present study, we applied a method for an unequivocal identification of the graft cells without interfering cell metabolism or behaviour using in situ hybridisation (ISH) of human specific Alu sequences. Visualisation of the strong extended nuclear signal of Alu sequences was much easier than that of the small nuclear signals of donor-specific sex chromosome probes. With Alu probe, even single graft cells can be identified and their development can be observed in short-term and long-term studies. With this procedure, we could prove that donor cells were injected correctly into the subretinal space by a special injection technique that we developed previously. In combination with immunohistochemistry, donor cells could be clearly discriminated from macrophages, which contained phagocytosed donor cell fragments. Application of these ISH methods for species-specific identification was valuable for follow-up-studies of RPE transplantation. 相似文献
56.
Nadja Bogdanova Beate Lemcke Arseni Markoff Hartmut Pollmann Bernd Dworniczak Antonin Eigel Jürgen Horst 《Human mutation》2002,19(1):84-84
Haemophilia A is a X‐linked bleeding disorder, caused by deficiency in the activity of coagulation factor VIII due to mutations in the corresponding gene. The most common defect in patients is an inversion of the factor VIII gene that accounts for nearly 45% of individuals with severe hemophilia A. Point mutations and small deletions/insertions are responsible for the majority of cases with moderate to mild clinical course and for half of the severe hemophilia A occurrences. The majority of these mutations are “private”, because of the high mutation rate for this particular gene. We report on eleven pathological changes in the factor VIII sequence detected in male patients with haemophilia A or in female obligate carriers. Seven of these mutations are novel [E204N, E265X, M320T, F436C, S535C, N2129M and R2307P] and four have been previously identified [V162M, R527W, R1966X, and R2159C]. Genotype‐phenotype correlations and computer prediction analysis on the effect of missense mutations on the secondary structure of the factor VIII protein are performed and the relationships evaluated. © 2001 Wiley‐Liss, Inc. 相似文献
57.
High contrast can be obtained in ultrathin sections of bacterial cells embedded in the low-temperature resin Lowieryl by post-staining of the sections on an aqueous ruthenium red solution. Post-staining with lead citrate can be omitted. Combination with post-staining with uranyl acetate results in further improvement of contrast. This is shown for Gram-positive, Gram-negative, and methanogenic bacteria. Improved visibility is demonstrated for wall layers including slime and capsule, cytoplasmic membrane, nucleoid, envelope of PHB inclusion bodies, polyphosphate, and intracellular defective bacteriophages. The procedure is suited as post-staining for immunocytochemical analyses. 相似文献
58.
J. A. R. Smith J. Watkins W. Lorenz 《Journal of molecular medicine (Berlin, Germany)》1985,63(19):1005-1008
Summary The past decades have seen considerable shifts of emphasis in surgical care. The recognition that pus was not laudable, was followed by a realisation that not all complications were inevitable and that prophylaxis could effectively reduce the incidence of most common problems in the post-operative period. As anaesthesia has become safer, it has been possible to embark on more intricate and prolonged procedures and for sufficient time to be available to ensure adequate intraoperative care.These two phenomena have firstly increased the complexity of management in the post-operative period, and have brought this aspect of surgical care more obviously to the limelight. However, many separate disciplines are involved in the care of the patient post-operatively, and the Symposium was organised1 to bring the different groups together to identify the areas of recent development in the different specialities and to integrate the overall care of the individual patient.Abbreviations ARDS
adult respiratory distress syndrome
- DIC
disseminated intravascular clotting 相似文献
59.
H. Bechtold J. Lorenz L. S. Weilemann T. Meinertz D. Trenk K. Andrassy E. Jähnchen 《Journal of molecular medicine (Berlin, Germany)》1984,62(18):885-886
Summary In three patients treated with cephalosporins (one patient with latamoxef, two patients with cefazedone) vitamin K1 was injected to investigate whether this was followed by an increase in vitamin K1 2,3-epoxide plasma concentrations as compared to controls. Such a rise in K1-epoxide concentrations in the plasma can be demonstrated following treatment with coumarins. This reflects an inhibition of the vitamin K1-epoxide reductase in the liver. Coumarins are thought to induce hypoprothrombinaemia by such a mechanism. In all three patients we found a considerable increase in the vitamin K1-epoxide plasma concentrations following injection of 10 mg vitamin K1, whereas in normal subjects only traces of K1-epoxide could be detected (<0.030 µg/ml). The K1-epoxide concentrations found in our three patients treated with cephalosporins were 0.12, 0.16 and 0.19 µg/ml, respectively. This indicates that latamoxef or cefazedone might reduce clotting factor synthesis by a coumarin-like mechanism of action in these patients. Although the effect of cephalosporins in enhancing vitamin K1-epoxide plasma concentrations is less than that of coumarins, it might cause severe hypoprothrombinaemia in the presence of latent vitamin K deficiency.Abbreviation PT
prothrombin time
- TT
thrombin time
- PTT
partial thromboplastin time
- PC
platelet count
- ICU
intensive care unit
- EEG
electroencephalogram
- K1-epoxide
vitamin K1 2,3-epoxide 相似文献
60.