全文获取类型
收费全文 | 8371篇 |
免费 | 592篇 |
国内免费 | 52篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 223篇 |
妇产科学 | 249篇 |
基础医学 | 1376篇 |
口腔科学 | 179篇 |
临床医学 | 908篇 |
内科学 | 1669篇 |
皮肤病学 | 182篇 |
神经病学 | 848篇 |
特种医学 | 291篇 |
外国民族医学 | 7篇 |
外科学 | 736篇 |
综合类 | 42篇 |
一般理论 | 2篇 |
预防医学 | 706篇 |
眼科学 | 86篇 |
药学 | 656篇 |
中国医学 | 19篇 |
肿瘤学 | 792篇 |
出版年
2024年 | 9篇 |
2023年 | 57篇 |
2022年 | 86篇 |
2021年 | 216篇 |
2020年 | 153篇 |
2019年 | 203篇 |
2018年 | 210篇 |
2017年 | 171篇 |
2016年 | 239篇 |
2015年 | 244篇 |
2014年 | 350篇 |
2013年 | 416篇 |
2012年 | 676篇 |
2011年 | 802篇 |
2010年 | 421篇 |
2009年 | 379篇 |
2008年 | 606篇 |
2007年 | 652篇 |
2006年 | 607篇 |
2005年 | 581篇 |
2004年 | 493篇 |
2003年 | 402篇 |
2002年 | 390篇 |
2001年 | 54篇 |
2000年 | 45篇 |
1999年 | 68篇 |
1998年 | 83篇 |
1997年 | 79篇 |
1996年 | 65篇 |
1995年 | 45篇 |
1994年 | 44篇 |
1993年 | 32篇 |
1992年 | 31篇 |
1991年 | 14篇 |
1990年 | 9篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 10篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 8篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1970年 | 4篇 |
1968年 | 2篇 |
排序方式: 共有9015条查询结果,搜索用时 15 毫秒
81.
Dr. Thomas Menke Petra Niklowitz Bernhard Schlüter Dirk Buschatz Eckardt Trowitzsch Werner Andler 《Somnologie - Schlafforschung und Schlafmedizin》2003,7(2):37-42
Summary Question of the study Respiratory instability as well as tissue damage by free radicals (oxidative stress) have been hypothesized to play a role in cases of sudden and unexpected infant death in the first year of life. The ratio of the oxidized/reduced form of redox compounds in the circulation could be used as a marker of oxidative stress. Therefore, the sleep apnoea rate and redox status of coenzyme Q10 (CoQ10) (percentage of the oxidized form in total CoQ10) were measured in a population of clinically healthy infants in their first year of life in order to study whether a physiological parameter of respiratory instability is related to a biochemical parameter of oxidative stress. Patients and methods Between May and December 1999, 323 infants in the first year of life were referred to a paediatric sleep laboratory. Sleep apnoea rate, periodic breathing and parameters of oxygenation (SaO2 and TcPO2 ) were calculated based on polysomnographic recordings. The CoQ10 redox status was calculated based on high-pressure liquid chromatographic (HPLC) analysis. Results Statistical analysis showed an age-dependent decrease in apnoea rate ( r = – 0.38) and CoQ10 redox status ( r = – 0.40). An increased CoQ10 redox status (median: 16.6 %; range: 7.3 – 29.7 %) was found in infants with high apnoea rates above the 90th percentile of a reference group in comparison with infants with apnoea rates below the 90th percentile of a reference group (median: 10.4 %; range: 5.1 – 20.4 %; P = 0.031). Conclusions These findings may indicate that high apnoea rates are accompanied by increased formation of free radicals in clinically healthy infants in the first year of life. 相似文献
82.
Wim H. J. P. Linssen Martin J. Van den Bent Han G. Brunner Petra J. E. Poels 《American journal of medical genetics. Part A》1994,51(1):81-82
We report on 3 sibs (2 males and one female) with sensorineural deafness. The presence of ovarian dysgenesis in the girl suggested a diagnosis of Perrault syndrome. In addition our patients have a sensory polyneuropathy and amelogenesis imperfecta. Two of the patients have mild mental retardation, fine choreatic movements, and dyspraxia. It is discussed whether these findings are part of a separate clinical entity or should be included within the spectrum of the Perrault syndrome. © 1994 Wiley-Liss, Inc. 相似文献
83.
Significant association of strictures and internal fistula formation in Crohn’s disease 总被引:1,自引:0,他引:1
Oberhuber G Stangl PC Vogelsang H Schober E Herbst F Gasche C 《Virchows Archiv : an international journal of pathology》2000,437(3):293-297
Intestinal inflammation in Crohn’s disease (CD) may be complicated by the occurrence of strictures and fistulae. The pathogenesis
of fistula formation is unknown. We therefore wanted to determine whether mechanical factors might contribute to the development
of fistulae. Furthermore, we tried to define the path of internal fistulae through the muscular layer. For this purpose, surgical
resection specimens from 42 consecutive patients with CD were prospectively studied. In gross examination the whole bowel
was cut into circumferential cross sections 0.3 cm thick. Abnormal areas were histologically examined. Strictures were found
in 38 patients (90.5%), and fistulae were observed in 27 (64.3%) patients. In 11 (40.7%) specimens fistulae were found within
a stricture, in 15 (55.6%) at the proximal end, and in 1 (3.7%) no stricture was found. In 7 (25.9%) cases with fistulae,
herniated mucosa was found within the muscularis propria or the subserosa. In 7 (25.9%) cases a blood vessel was identified
near a fistula traversing the muscularis propria. From these findings we conclude that that mechanical factors may contribute
to fistula formation. This is further supported by the fact that fistulae appear to traverse the muscular layer along piercing
vessels.
Received: 21 January 2000 / Accepted: 7 March 2000 相似文献
84.
85.
Wolfgang Müller-Felber Klaus Küllmer Petra Fischer Carl-Detlev Reimers Stefan Wagner Ullrich Harland Martin Schmidt-Achert Dieter Pongratz 《Virchows Archiv : an international journal of pathology》1993,422(4):277-283
Leu-19 antigen, which seems to be identical with neural cell adhesion molecule (N-CAM), plays a major role in the innervation of muscle cells, and in adult muscle appears after denervation and during regeneration of muscle fibres, where it acts as part of a signalling system increasing the probability of re-innervation. This combined enzyme-histochemical and immunohistochemical study examined whether this signalling process was regulated in a uniform or differential pattern for type 1 and type 2 muscle fibres. The subscapular nerve of 18 rabbits was transsected with subsequent complete denervation of the supraspinatus muscle. Leu19 and N-CAM immunohistochemistry was performed 2 to 64 days after surgery. Whereas in normal muscle there are virtually no Leu-19/N-CAM positive muscle fibres; from day 2 after denervation an increasing proportion of fibres expressed Leu-19/N-CAM, prior to any neurogenic atrophy. In the early stage of denervation Leul9/N-CAM expression was confined to type 1 fibres. After 11 days nearly all fibres were Leul9/N-CAM positive irrespective of their fibre type. Sixty-four days after denervation type 1 fibres became Leu19/N-CAM negative, while atrophic type 2 fibres showed intensive staining. Thus, expression of Leu-19 antigenity is differently regulated in both fibre types. 相似文献
86.
D. J. Schendel Ralph Oberneder Christine S. Falk Petra Jantzer Susanne Kressenstein Barbara Maget Alfons Hofstetter Gert Riethmüller Elfriede Nößner 《Journal of molecular medicine (Berlin, Germany)》1997,75(6):400-413
Renal cell carcinomas belong to the small group of tumors that are able to induce antitumor responses. Here we describe two
general types of cytotoxic effector lymphocytes that can eliminate autologous tumor cells and discuss the role that major
histocompatibility complex encoded molecules play in governing their specificities. Improved understanding of the cellular
and molecular basis of renal cell carcinoma recognition opens new avenues of research with the potential to develop better
immunotherapies for patients with metastatic disease.
Received: 24 July 1996 / Accepted: 1 November 1996 相似文献
87.
Willinger B Kopetzky G Harm F Apfalter P Makristathis A Berer A Bankier A Winkler S 《Journal of clinical microbiology》2004,42(1):478-480
Disseminated infection with the coelomycetous fungus Nattrassia mangiferae is a very rare disease affecting only the immunocompromised host. We report the first case of a disseminated infection with spondylodiscitis and granular skin lesions due to N. mangiferae in a renal transplant patient. 相似文献
88.
Petra C. Arck David A. Ferrick Darlene Steele-Norwood Ken Croitoru David A. Clark 《American journal of reproductive immunology (New York, N.Y. : 1989)》1997,37(1):87-93
PROBLEM: T cells are present at the feto-maternal interface, but their function during pregnancy has not been fully elucidated. T cells bearing γλ T-cell receptor (TCR) may be particularly important, as some subsets can react to trophoblast cells by producing cytokines, such as interleukin-2 (IL-2). METHOD: We depleted T cells bearing the γλ receptor by injecting monoclonal antibodies (mAB) into females of the abortion-prone animal model CBA x DBA/2. We investigated the percentage and number of γλ T-cell receptor positive (TCR)+ cells in decidua and spleen during pregnancy in control and γλ-depleted female mice. Pregnant females were also exposed to ultrasonic sound stress to boost the abortion rate. RESULTS: Stress failed to increase the abortion rate in the γλ TCR-depleted mice. FACScan analysis show that the ratio of cells bearing the γλ TCR dramatically decreased after injection of mAB to the γλ TCR in spleen and decidua, these cells recovered six days after depletion, showing a change in cytokine pattern. Levels of TNF-α in decidual γλ T cells decreased; similar effects of decreasing Th1 cytokines could be observed in splenic γλ T cells. We further identified increased levels of intracellular TNF-α in the Vλ4 subset in the decidua, compared to spleen. CONCLUSIONS: Trophoblast recognition by the Vλ4 T-cell subset in the decidua may cause the release of abortogenic cytokines such as TNF-α. Depletion of such γλ TCR T cells during early pregnancy may promote successful pregnancy outcome in normal pregnancy and prevent stress-induced abortions. 相似文献
89.
Cravens PD Melkus MW Padgett-Thomas A Islas-Ohlmayer M Del P Martin M Garcia JV 《Stem cells (Dayton, Ohio)》2005,23(2):264-278
Dendritic cells (DCs) are derived from CD34+ progenitors and play a central role in the development of immune responses and in tolerance. Their therapeutic potential underscores the need for in vivo models that accurately recapitulate human DC development and function to provide a better understanding of DC biology in health and disease. Using nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice transplanted with human CD34+ cells as a model of human hematopoiesis, we examined DC ontogeny. Progenitors of both myeloid (m) and plasmacytoid (p) DCs were identified in the bone marrow of mice up to 24 weeks after transplant, indicating ongoing and sustained production of DCs after initial engraftment. To determine whether human DCs derived from transplanted stem cells were functional, their response to acute inflammation using lipopolysaccharide (LPS) was examined. Eighteen hours after LPS administration, a dramatic increase in the plasma levels of the human inflammatory cytokines interleukin (IL)-8, IL-10, tumor necrosis factor-alpha, and IL-12p70 was observed. Only mDCs and not pDCs responded in vivo to LPS by upregulating CD86 and CD83. In vivo activation of human mDCs resulted in a substantial increase in the ability of mDCs to induce the proliferation of naive human T cells. Taken together, these data indicate that human CD34+ cells seem to have differentiated appropriately within the NOD/SCID microenvironment into DCs that are developmentally, phenotypically, and functionally similar to the DC subsets found in humans. 相似文献
90.
Francisella tularensis is the etiological agent of tularemia, a serious and occasionally fatal disease of humans and animals. In humans, ulceroglandular tularemia is the most common form of the disease and is usually a consequence of a bite from an arthropod vector which has previously fed on an infected animal. The pneumonic form of the disease occurs rarely but is the likely form of the disease should this bacterium be used as a bioterrorism agent. The diagnosis of disease is not straightforward. F. tularensis is difficult to culture, and the handling of this bacterium poses a significant risk of infection to laboratory personnel. Enzyme-linked immunosorbent assay- and PCR-based methods have been used to detect bacteria in clinical samples, but these methods have not been adequately evaluated for the diagnosis of pneumonic tularemia. Little is known about the virulence mechanisms of F. tularensis, though there is a large body of evidence indicating that it is an intracellular pathogen, surviving mainly in macrophages. An unlicensed live attenuated vaccine is available, which does appear to offer protection against ulceroglandular and pneumonic tularemia. Although an improved vaccine against tularemia is highly desirable, attempts to devise such a vaccine have been limited by the inability to construct defined allelic replacement mutants and by the lack of information on the mechanisms of virulence of F. tularensis. In the absence of a licensed vaccine, aminoglycoside antibiotics play a key role in the prevention and treatment of tularemia. 相似文献