全文获取类型
收费全文 | 5881篇 |
免费 | 396篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 79篇 |
儿科学 | 102篇 |
妇产科学 | 137篇 |
基础医学 | 903篇 |
口腔科学 | 42篇 |
临床医学 | 481篇 |
内科学 | 1390篇 |
皮肤病学 | 70篇 |
神经病学 | 546篇 |
特种医学 | 430篇 |
外科学 | 720篇 |
综合类 | 33篇 |
预防医学 | 231篇 |
眼科学 | 78篇 |
药学 | 518篇 |
中国医学 | 19篇 |
肿瘤学 | 532篇 |
出版年
2023年 | 20篇 |
2022年 | 32篇 |
2021年 | 91篇 |
2020年 | 48篇 |
2019年 | 61篇 |
2018年 | 77篇 |
2017年 | 63篇 |
2016年 | 101篇 |
2015年 | 106篇 |
2014年 | 145篇 |
2013年 | 191篇 |
2012年 | 356篇 |
2011年 | 357篇 |
2010年 | 193篇 |
2009年 | 188篇 |
2008年 | 379篇 |
2007年 | 346篇 |
2006年 | 426篇 |
2005年 | 372篇 |
2004年 | 337篇 |
2003年 | 320篇 |
2002年 | 324篇 |
2001年 | 141篇 |
2000年 | 142篇 |
1999年 | 141篇 |
1998年 | 112篇 |
1997年 | 71篇 |
1996年 | 67篇 |
1995年 | 71篇 |
1994年 | 55篇 |
1993年 | 53篇 |
1992年 | 74篇 |
1991年 | 61篇 |
1990年 | 67篇 |
1989年 | 68篇 |
1988年 | 52篇 |
1987年 | 51篇 |
1986年 | 47篇 |
1985年 | 38篇 |
1984年 | 37篇 |
1983年 | 49篇 |
1982年 | 44篇 |
1981年 | 23篇 |
1980年 | 23篇 |
1979年 | 36篇 |
1978年 | 24篇 |
1976年 | 21篇 |
1975年 | 27篇 |
1973年 | 20篇 |
1970年 | 20篇 |
排序方式: 共有6311条查询结果,搜索用时 31 毫秒
1.
2.
Age determines memory for face identity and expression 总被引:1,自引:1,他引:0
Egemen SAVASKAN Sandra Elisabeth MÜLLER reas BÖHRINGER Christine PHILIPPSEN Franz MÜLLER-SPAHN Hartmut SCHÄCHINGER 《Psychogeriatrics》2007,7(2):49-57
Background: The recognition of facial expressions is an important component of emotion processing which contributes to interactional behavior. One of the factors highly associated with potential decline of ability in behavioral tasks is age. Methods: We have investigated age‐related changes in facial identity and expression memory of healthy subjects in three age groups: young adults (20–40 years), elderly adults (60–80 years) and, for the first time in the literature, very old adults (over 80 years of age). Using a picture test, photographs of faces with happy or angry expressions were presented to study participants during the encoding task, and the memory for identity and emotional facial expression was investigated in a subsequent recognition task showing emotionally neutral faces. Half of the faces presented in the recognition task were initially shown in the encoding task. Results: Age interacted with the memory process: the ability to recognize both facial identity and emotional expression declined with advanced age. Happy facial expressions were better recognized in all age groups. Although there was a continuous overall decrease in recognition of both happy and angry expressions with advanced age, the effect favoring happy facial expressions was stable also in very old adults. Other factors such as gender or educational level did not affect the memory process for facial expressions. Conclusions: Our findings suggest that age is a significant determinant of memory for facial identity and emotional expression, and that, similar to younger adults, the recognition process of the elderly favors happy emotional facial expressions. 相似文献
3.
J P Dutcher C E Riggs J J Strauman B Link P H Wiernik 《Clinical pharmacology and therapeutics》1989,45(4):424-428
In a phase I-II study, 21 patients with relapsed or refractory acute leukemia were treated with 4'-deoxydoxorubicin (esorubicin), the 4'-deoxy derivative of doxorubicin. Four of 14 evaluable patients with acute nonlymphocytic leukemia (ANLL) in relapse or refractory to other anthracyclines achieved partial response (28.5%). Pharmacokinetics were similar to those of the parent compound, doxorubicin. Esorubicin has activity in ANLL and has pharmacologic properties comparable to those of other anthracyclines. Dose-limiting toxicity occurs in the form of mucositis, which may limit its use in combination with other antileukemic drugs. 相似文献
4.
Minoo Lenarz Martin Durisin Hartmut Becker Almuth Brandis Thomas Lenarz 《Skull base》2007,17(2):153-156
We report a case of synchronous olfactory bulb meningioma and undifferentiated carcinoma of the nose and paranasal sinuses that involved and destroyed the anterior skull base and mimicked intracranial invasion by a carcinoma. The heterogeneity of tissue types in the skull base gives rise to a diverse variety of benign and malignant neoplasms which have totally different prognoses. Synchronous development of benign and malignant primary tumors both originating from and involving the skull base at the same location is very rare and may cause confusion for both the skull base surgeon and neuroradiologist. 相似文献
5.
Christian J. Sauder Cheryl X. Zhang Malen A. Link W. Paul Duprex Kathryn M. Carbone Steven A. Rubin 《Vaccine》2009
The recent global resurgence of mumps has drawn attention to the continued need for robust mumps immunization programs. Unfortunately, some vaccines derived from inadequately attenuated vaccine strains of mumps virus have caused meningitis in vaccinees, leading to withdrawal of certain vaccine strains from the market, public resistance to vaccination, or in some cases, cessation of national mumps vaccination programs. The most widely implicated mumps vaccine in cases of postvaccination meningitis is derived from the Urabe AM9 strain, which remains in use in some countries. The Urabe AM9 vaccine virus has been shown to exhibit a considerable degree of nucleotide and amino acid heterogeneity. Some studies have specifically implicated variants containing a lysine residue at amino acid position 335 in the hemagglutinin-neuraminidase (HN) protein with neurotoxicity, whereas a glutamic acid residue at this position was associated with attenuation. To test this hypothesis we generated two modified Urabe AM9 cDNA clones coding either for a lysine or a glutamic acid at position 335 in the HN gene. The two viruses were rescued by reverse genetics and characterized in vitro and in vivo. Both viruses exhibited similar growth kinetics in neuronal and non-neuronal cell lines and were of similar neurotoxicity when tested in rats, suggesting that amino acid 335 is not a crucial determinant of Urabe AM9 growth or neurovirulence. 相似文献
6.
Die therapieinduzierte Neutropenie kann mit den Kolonie stimulierenden Faktoren (CSF) der Granulopoese (G-CSF und GM-CSF)
vermieden,abgemildert oder in ihrer Zeitdauer verkürzt werden. Die CSF erm?glichen die Mobilisation h?matopoetischer Stammzellen
in das Blut und deren Sammlung für die Transplantation nach Hochdosistherapie.Diese Faktoren sind daher essenziell in der
Supportivtherapie maligner Erkranklungen. Der Arbeitskreis Supportivma?nahmen in der Onkologie (ASO) der Deutschen Krebsgesellschaft
hat Richtlinien zur Therapie mit den Kolonie stimulierenden Faktoren entwickelt, die unterschiedlichen klinischen Situationen
angepasst sind. Der vollst?ndige Text wurde 12/2001 in “Der Onkologe” publiziert [23], er ist auch auf der Homepage des ASO
unter http://www.onkosupport.de zu finden [24].
Prof.Dr. H. Link H?matologie, Internistische Onkologie, Endokrinologie, Medizinische Klinik I, Westpfalz-Klinikum Kaiserslautern, Akademisches
Lehrkrankenhaus der Johannes-Gutenberg-Universit?t Mainz, 67653 Kaiserslautern, E-Mail: hlink@westpfalz-klinikum.de 相似文献
7.
Holger F. Boehm Felix Eckstein Caecilia Wunderer Volker Kuhn Eva-Maria Lochmueller Karin Schreiber Dirk Mueller Ernst J. Rummeny Thomas M. Link 《Journal of clinical densitometry》2005,8(4):488-494
We tested the hypothesis that bone mineral density (BMD) and bone mineral content (BMC) in proximal human femur specimens in the upper neck region of interest (ROI) and femoral neck axis length (FNAL) provide a significantly better prediction of femoral bone strength than standard ROIs in vitro. BMD and BMC were measured in 110 proximal femur specimens using a standard dual-energy X-ray absorptiometry (DXA) scanner. The analysis included a new ROI in the upper neck as well as the standard ROIs. FNAL was obtained from the scan images. The specimens' failure-load was measured in a mechanical loading device, simulating a fall on the greater trochanter. For the standard ROIs, correlations between failure-load and BMD ranged from R2 = 0.64 (shaft ROI) to R2 = 0.70, p < 0.001 (femoral neck). Prediction of strength by BMD did not significantly differ from those of BMC (R2 ranging from 0.65 to 0.75, p < 0.001). In the upper neck ROI, for both BMD and BMC correlations with failure-load were higher (R2 = 0.76 and 0.81, respectively; p < 0.001). A lower, yet still significant, correlation was found between FNAL and bone strength (R2 = 0.23, p < 0.001). Normalization of failure-load with respect to FNAL did not significantly increase the correlations with densitometric measures. This study provides in vitro evidence indicating that among the ROIs of the proximal femur the newly defined upper neck ROI provides the best prediction of bone strength. Only a weak association was observed between failure load and FNAL. 相似文献
8.
Manuel Modolell Ines M. Corraliza Franz Link Germn Soler Klaus Eichmann 《European journal of immunology》1995,25(4):1101-1104
Activation with lipopolysaccharide induces macrophages to produce the enzymes arginase and nitric oxide (NO) synthase. Both enzymes use as a substrate the amino acid L-arginine, which can be either hydrolyzed by arginase to urea and ornithine or oxidized by NO synthase to NO and citrulline. NO is important in the bactericidal and cytotoxic activities of macrophages. An equivalent functional role of arginase and its products is not known. We tested the induction of arginase in bone marrow-derived macrophages by endogenous mediators that are known to induce NO synthase, such as interferon-γ (IFN-γ), or suppress the induction of this enzyme, such as interleukin (IL)-4, IL-10, and prostaglandin E2 (PGE2). We find that PGE2 and the TH2 cytokines IL-4 and IL-10 are potent inducers of arginase. In contrast, the TH 1 cytokine IFN-γ does not induce arginase. Simultaneous application of both types of mediators leads to reduced induction of both arginase and NO synthase. Exposure of macrophage cultures to inducers of NO synthase exhausts their ability to respond subsequently to inducers of arginase. Conversely, exposure of the cells to inducers of arginase exhausts their ability to respond subsequently to inducers of NO synthase. The results are consistent with a competition of both enzymes for their substrate, L-arginine, with a reciprocal inhibition in the induction of both enzymes, or a combination of both phenomena. The enzymes NO synthase and arginase appear to define two alternate functional states of macrophages, induced by TH 1 and TH 2 cytokines, respectively. 相似文献
9.
Felix Eckstein Maiko Matsuura Volker Kuhn Mathias Priemel Ralph Müller Thomas M Link Eva-Maria Lochmüller 《Journal of bone and mineral research》2007,22(6):817-824
In this study, we characterize bone microstructure, specifically sex differences, at multiple skeletal sites in 165 subjects >52 yr of age, using microCT technology in vitro. Significant sex differences are observed at the distal radius, femoral neck, and femoral trochanter, but not at the iliac crest, calcaneus, and lumbar vertebral body. Correlations in BV/TV between sites ranged from r = 0.13 to 0.56. INTRODUCTION: The goals of this study were (1) to assess potential sex differences of bone microstructure and their difference between skeletal sites and (2) to explore the relationship of trabecular microstructural properties between relevant skeletal sites. MATERIALS AND METHODS: Trabecular bone microstructural properties were measured in vitro in 165 subjects 52-99 yr of age using microCT. Defined volumes of interest (cylinders with 6 mm diameter and 6 mm length) were scanned at a resolution of 26 microm (isotropic) in six different anatomical sites: distal radius, femoral neck and trochanter, iliac crest, calcaneus, and second lumbar vertebral body. RESULTS: At the radius and femoral neck, trabecular bone displayed a more plate-like structure, thicker trabeculae, smaller separation/higher trabecular number, higher connectivity, and a higher degree of anisotropy in men than in women (p < 0.05). At the trochanter, men displayed more plate-like structure and thicker trabeculae (p < 0.05), but no differences in trabecular separation or other parameters compared with the women. At the calcaneus, iliac crest, and second lumbar vertebra none of the bone parameters displayed significant differences between sexes. The BV/TV at one site explained a range of only 2-32% of the variability at other sites. CONCLUSIONS: These results suggest that trabecular bone microstructural properties are remarkably heterogeneous throughout the skeleton. Significant differences between men and women are observed at some, but not at all, sites. The magnitude of sex differences in trabecular microstructure coincides with that of fracture incidence observed for some of the sites in epidemiological studies. 相似文献
10.
股骨干骨折--逆行穿钉与顺行穿钉的探讨 总被引:1,自引:0,他引:1
在对股骨骨折进行逆行和顺行置入髓内钉治疗时,两种治疗方法产生很高的愈合率和相近的畸形愈合率。虽然未经过一致的认定,但那些接受顺行穿钉治疗的患者愈合较快。患者在接受逆行穿钉治疗后膝关节疼痛频繁出现,然而髋关节疼痛和异位骨化现象却在接受顺行穿钉治疗的患者中存在。患其它并发症的几率也无显著增长。因此不能决定功能结果。 相似文献