全文获取类型
收费全文 | 15779篇 |
免费 | 756篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 335篇 |
儿科学 | 343篇 |
妇产科学 | 317篇 |
基础医学 | 2701篇 |
口腔科学 | 349篇 |
临床医学 | 1407篇 |
内科学 | 2609篇 |
皮肤病学 | 399篇 |
神经病学 | 1615篇 |
特种医学 | 841篇 |
外科学 | 2264篇 |
综合类 | 110篇 |
一般理论 | 2篇 |
预防医学 | 779篇 |
眼科学 | 531篇 |
药学 | 1040篇 |
中国医学 | 19篇 |
肿瘤学 | 925篇 |
出版年
2022年 | 97篇 |
2021年 | 172篇 |
2020年 | 115篇 |
2019年 | 196篇 |
2018年 | 251篇 |
2017年 | 193篇 |
2016年 | 304篇 |
2015年 | 307篇 |
2014年 | 371篇 |
2013年 | 468篇 |
2012年 | 866篇 |
2011年 | 803篇 |
2010年 | 528篇 |
2009年 | 519篇 |
2008年 | 702篇 |
2007年 | 815篇 |
2006年 | 861篇 |
2005年 | 877篇 |
2004年 | 825篇 |
2003年 | 737篇 |
2002年 | 778篇 |
2001年 | 372篇 |
2000年 | 298篇 |
1999年 | 291篇 |
1998年 | 226篇 |
1997年 | 184篇 |
1996年 | 159篇 |
1995年 | 130篇 |
1994年 | 110篇 |
1993年 | 106篇 |
1992年 | 139篇 |
1991年 | 155篇 |
1990年 | 158篇 |
1989年 | 160篇 |
1988年 | 160篇 |
1987年 | 125篇 |
1986年 | 112篇 |
1985年 | 130篇 |
1984年 | 120篇 |
1983年 | 85篇 |
1982年 | 73篇 |
1981年 | 86篇 |
1979年 | 111篇 |
1978年 | 82篇 |
1977年 | 89篇 |
1976年 | 77篇 |
1975年 | 78篇 |
1974年 | 83篇 |
1973年 | 73篇 |
1972年 | 83篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Chwieralski CE Schnurra I Thim L Hoffmann W 《American journal of respiratory cell and molecular biology》2004,31(5):528-537
Injured areas of the respiratory epithelium are subject to rapid repair by the migration of adjacent epithelial cells, a process termed "restitution". Rapid re-epithelialization is promoted by interactions between migrating cells and the extracellular matrix proteins. Furthermore, epidermal growth factor (EGF) as well as trefoil factor family (TFF) peptides are well known regulators of epithelial restitution due to their motogenic effects. Migration of the human bronchial epithelial cell line BEAS-2B in modified Boyden chambers was used as a model system for airway restitution. EGF or recombinant human TFF2 or TFF3 showed mainly chemotactic activity. The motogenic response was strictly dependent upon a haptotactic substrate, but to different degrees. EGF induced phosphorylation of extracellular signal-regulated kinases (ERK) 1/2, c-Jun-N-terminal kinase, p38, Akt, and p70S6K in BEAS-2B cells. Using specific inhibitors, the signaling cascades responsible for the motogenic response were shown to differ drastically when EGF was compared with TFF2. The motogenic effect of TFF2 was previously demonstrated to depend on ERK1/2 and protein kinase C activation; whereas the EGF-triggered motogenic response was completely independent of ERK1/2 activation but sensitive to the inhibition of phosphoinositide 3-kinase, p38, protein kinase C, or nuclear factor kappaB. However, the motogenic effects of EGF and TFF2 are additive. These data suggest that luminal EGF and TFF peptides can act synergistically in the human respiratory epithelium to enhance rapid repair processes in the course of diseases such as asthma. 相似文献
52.
Werner M Mattis A Aubele M Cummings M Zitzelsberger H Hutzler P Höfler H 《Virchows Archiv : an international journal of pathology》1999,435(5):469-472
The 20q13 region harboring recently described putative oncogenes is frequently amplified in invasive ductal carcinoma (IDC).
The aim of this study was to examine the 20q13 copy number in intraduct hyperplasia (IH), atypical duct hyperplasia (ADH),
and ductal carcinoma in situ (DCIS) adjacent to IDC. In 5 patients, comparative genomic hybridization (CGH) after laser microdissection
revealed 20q13 amplification in four of five cases of IH, in all of three cases of IH with atypia, all five of DCIS, and all
five of IDC. Fluorescence in situ hybridization (FISH) confirmed the amplification at 20q13.2 in IH in the two specimens analyzed.
The amplification rate, however, was higher in DCIS and IDC. In phenotypically normal ductal epithelium normal values were
found for 20q13 copy number by FISH (n=2) and CGH (n=5). Although the number of cases presented here is small, our results suggest that mutations in the 20q13.2 region in IH
may be associated with accelerated proliferation and hyperplasia of the ductal epithelium. Progression to DCIS and ICD is
accompanied by a further increase in the 20q13.2 copy number.
Received: 17 March 1999 / Accepted: 22 June 1999 相似文献
53.
54.
Helmut Brunner Werner Schaeg Ursula Brück Ulrich Schummer Hans-Gerd Schiefer 《Medical microbiology and immunology》1977,163(1):25-35
A radioimmunoassay (RIA) which depends on the property of protein A ofStaphylococcus aureus to combine with the Fc-fragment of immunoglobulins was developed.This technique was employed to measure antibodies in human and various animal sera. It could be demonstrated that the staphylococcal RIA was at least as sensitive as the previously described radioimmunoprecipitation technique in detecting antibodies toM.pneumoniae in human sera. In addition, antibodies toM.pneumoniae could be demonstrated in sera of hamsters intranasally inoculated with the organisms. Antibodies could also be demonstrated in rabbit sera after immunization withM.pneumoniae. The test proved to be considerably more sensitive than conventional tests for detection of antibodies to the organisms. The test requires only small amounts of reagents and is relatively inexpensive.The results were presented in a preliminary form at the annual meeting of the Local Branch of the American Society for Microbiology, Frankfurt, March 1976 and the 77th ordinary meeting of the Society for General Microbiology, Glasgow, September 1976 相似文献
55.
Sturm G Kränke B Rudolph C Aberer W 《The Journal of allergy and clinical immunology》2002,110(6):928-933
BACKGROUND: Hymenoptera venom immunotherapy in allergic patients is a well-established treatment modality for the prevention of systemic anaphylactic reactions caused by insect stings. A variety of therapy regimens exists, from conventional to rush and ultrarush modalities that operate on continuous or intermittent schedules. OBJECTIVE: The aim of this study was to report the 8-year experience with our rush venom immunotherapy regimen in predominantly high-risk patients and to compare data on safety and convenience with the results of 26 studies published from 1978 to 2001. METHODS: One hundred one patients allergic to bee, yellow jacket, or hornet venom were treated with rush Hymenoptera venom immunotherapy. Diagnosis and selection of patients for venom immunotherapy were carried out according to the recommendations of the European Academy of Allergology and Clinical Immunology. We used a 4-day regimen, and the incidence and nature of systemic reactions (SRs) were documented. Fifty-two patients were treated with honeybee venom, and 49 were treated with yellow jacket venom. RESULTS: One hundred (99%) patients reached the maintenance dose. We observed 8 injection-related SRs (0.47% of all injections given) in 7 (6.9%) patients. The number of SRs was higher in patients treated with bee venom extract (12%) compared with in patients receiving yellow jacket venom extract (2%). There was no significant difference in the risk of SRs between female and male patients. The incidence of SRs was considerably lower than the average of 17.8% reported in the literature. CONCLUSION: With a rush immunotherapy regimen over a time period of 8 years in predominantly high-risk patients, the incidence of SRs was low, despite the high number of patients with bee venom allergy, who are more likely to have side effects. Epinephrine as rescue medication was never necessary, and the regimen proved to be safe and convenient for both the patients and the medical staff. 相似文献
56.
Silvia Obenauer Christian Sohns Carola Werner Eckhardt Grabbe 《Journal of digital imaging》2006,19(3):258-263
The goal of this study was to evaluate the performance of a computer-aided detection (CAD) system in full-field digital mammography
(Senographe 2000D, General Electric, Buc, France) in finding out carcinomas depending on the parenchymal density. A total
of 226 mediolateral oblique (MLO) and 186 craniocaudal (CC) mammographic views of histologically proven cancers were retrospectively
evaluated with a digital CAD system (ImageChecker V2.3 R2 Technology, Los Altos, CA, USA). Malignant tumors were detected
correctly by CAD in MLO view in 84.85% in breasts with parenchymal tissue density of the American College of Radiology (ACR)
type 1, in 70.33% of the ACR type 2, in 68.12% of the ACR type 3, and in 69.70% of the ACR type 4. For the CC view, similar
results were found according to the ACR types. Using the chi-square and McNemar tests, there was no statistical significance.
However, a trend of better detection could be seen with decreasing ACR type. In conclusion, there seems to be a tendency for
breast tissue density to affect the detection rate of breast cancer when using the CAD system. 相似文献
57.
Gordon Lauc Annie-Pierre Seve Jean Hubert Mirna Flgel-Mrsic Werner E. G. Müller Heinz C. Schrder 《Mechanisms of ageing and development》1993,70(3):227-236
Previous studies have demonstrated the existence of nuclear carbohydrate binding proteins in a variety of mammalian cells with molecular masses of 35 000, 67 000, and 70 000 (CBP35, CBP67, and CBP70), which are associated with nuclear ribonucleoprotein (RNP) complexes. CBP35 consists of two domains, an aminoterminal portion that is homologous to certain regions of proteins of the heterogeneous nuclear RNP complex, and a carboxyl-terminal portion homologous to β-galactoside-specific lectins. CBP35 it has been proposed, like the glucose-specific lectin, CBP67, to guide RNP complexes through the nuclear pore. Here we show that the exposure of mature rats to stress induces an increase in nuclear CBP35 bound to CBP67 and retained on immobilized glucose. Nuclear extracts from the livers of old rats displayed no detectable stress response. This CBP35·CBP67 association detected in rat liver is considered with respect to the CBP35·CBP70 association recently observed in HL60 cell nuclear extracts. 相似文献
58.
Self-assembled monolayers (SAMs) of alkanethiols with various terminating groups (-OH, -CH3, -COOH) and binary mixtures of these alkanethiols were studied with respect to their hemocompatibility in vitro by means of freshly taken human whole blood. The set of smooth monomolecular films with graded surface characteristics was applied to scrutinize hypotheses on the impact of surface chemical-physical properties on distinct blood activation cascades, i.e. to analyze -OH surface groups vs. complement activation, acidic surface sites vs. contact activation/coagulation and surface hydrophobicity vs. thrombogenicity. Blood and model surfaces were analyzed after incubation for the related hemocompatibility parameters. Our results show that the adhesion of leukocytes is abolished on a -CH3 surface and greatly enhanced on surfaces with -OH groups. The opposite was detected for the adhesion of platelets. A strong correlation between the activation of the complement system and the adhesion of leukocytes with the content of -OH groups could be observed. The contact activation for hydrophilic surfaces was found to scale with the amount of acidic surface sites. However, the coagulation and platelet activation did not simply correlate with any surface property and were therefore concluded to be determined by a superposition of contact activation and platelet adhesion. 相似文献
59.
Bruce S. Seal Robert B. Klieforth Anthony E. Castro Werner P. Heuschele 《Methods in Cell Science》1988,11(2):49-55
Summary Cultures of fetal aoudad sheep kidney (FAK), bovine embryonic lung (BEL), and African green monkey kidney (Vero) cells were compared for differential replication of alcelaphine herpesviruses. Cell-free virus appears more rapidly when infected cells are incubated at 33° C rather than at 37° C. Events in the replication and morphologic development of several alcelaphine herpesvirus isolates have been documented using light and electron microscopy. Techniques for indirect immunofluorescence and serum virus neutralization are described. When virus free of host-cell contaminants is desired for biochemical analysis, virus isolates are initially purified on sucrose gradients and then further purified by density gradient centrifugation in Percoll. 相似文献
60.
Rapid identification of Escherichia coli by Fluorocult media and positive indole reaction. 总被引:3,自引:6,他引:3 下载免费PDF全文
To assess the specificity and sensitivity of Fluorocult media for the identification of Escherichia coli, the beta-glucuronidase activities of 1,258 bacterial strains, as well as 20 strains of Candida spp., were investigated. Fluorescence of colonies combined with positive indole reaction resulted in specificities of 99.6 to 99.8%. Sensitivities were 59.1% (MacConkey agar), 69.9% (brolacin agar), 85.5% (Columbia agar), and 85.8% (ECD agar). 相似文献