全文获取类型
收费全文 | 23184篇 |
免费 | 1169篇 |
国内免费 | 256篇 |
专业分类
耳鼻咽喉 | 253篇 |
儿科学 | 485篇 |
妇产科学 | 671篇 |
基础医学 | 2631篇 |
口腔科学 | 529篇 |
临床医学 | 1706篇 |
内科学 | 6226篇 |
皮肤病学 | 413篇 |
神经病学 | 2484篇 |
特种医学 | 897篇 |
外科学 | 3697篇 |
综合类 | 51篇 |
一般理论 | 4篇 |
预防医学 | 918篇 |
眼科学 | 285篇 |
药学 | 1361篇 |
中国医学 | 49篇 |
肿瘤学 | 1949篇 |
出版年
2024年 | 25篇 |
2023年 | 188篇 |
2022年 | 401篇 |
2021年 | 717篇 |
2020年 | 447篇 |
2019年 | 527篇 |
2018年 | 697篇 |
2017年 | 560篇 |
2016年 | 644篇 |
2015年 | 720篇 |
2014年 | 934篇 |
2013年 | 1132篇 |
2012年 | 1775篇 |
2011年 | 1805篇 |
2010年 | 1018篇 |
2009年 | 999篇 |
2008年 | 1632篇 |
2007年 | 1617篇 |
2006年 | 1460篇 |
2005年 | 1394篇 |
2004年 | 1362篇 |
2003年 | 1220篇 |
2002年 | 1080篇 |
2001年 | 160篇 |
2000年 | 127篇 |
1999年 | 169篇 |
1998年 | 188篇 |
1997年 | 169篇 |
1996年 | 172篇 |
1995年 | 127篇 |
1994年 | 86篇 |
1993年 | 96篇 |
1992年 | 96篇 |
1991年 | 72篇 |
1990年 | 71篇 |
1989年 | 82篇 |
1988年 | 53篇 |
1987年 | 70篇 |
1986年 | 52篇 |
1985年 | 42篇 |
1984年 | 58篇 |
1983年 | 51篇 |
1982年 | 36篇 |
1981年 | 41篇 |
1980年 | 42篇 |
1979年 | 20篇 |
1978年 | 15篇 |
1977年 | 23篇 |
1976年 | 15篇 |
1974年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Angelo Sghirlanzoni Davide Pareyson Claudio Benvenuti Giovanni Cei Vittorio Cosi Mariella Lombardi Mariaflavia Nicora Roberta Ricciardi Ferdinando Cornelio 《Journal of neurology》1992,239(3):165-169
Summary The efficacy of intranasally administered neostigmine was tested in 22 patients with generalized myasthenia gravis (MG). Topical therapy to the highly vascularized oropharynx proved to be quickly effective in 5–15 min both clinically and electrophysiologically. Twenty-eight MG patients were then recruited from different centres and their morning doses of oral pyridostigmine were substituted with intranasal neostigmine over a period of 2 or 3 weeks. Intranasal neostigmine proved to be equally efficacious in this regimen. No side-effect was noted even in 4 patients treated in this way for 1 year. Intranasal administration of anti-acetylcholinesterase may be very beneficial: (1) for patients with irregular absorption of oral doses; (2) early in the morning and every time a fast and temporary effect is needed; (3) in bulbar impairment and emergencies, in which a handy atomizer may be life-saving.Presented in part at the XIV World Congress of Neurology, New Delhi, 22–27 October 1989 相似文献
32.
Italy's mental health law of 1978 provided for the gradual phasing out of psychiatric hospitals (PH) and the creation of comprehensive community-based systems. However, these changes have taken place at different times and in different forms. There are now three different organizational and care models operating in Italy: in the first, common in Southern Italy, the former PH and the new general hospital general wards (GHPW) coexist; in the second, outpatient departments complement the above facilities, but the hospital activity remains central; in the third model, a community model has been given priority-the so-called community priority. While many reports have been published describing the activity of some of the services adhering to the third model, no report has been published specifically describing the activity of services which work according to the second model, such as Cremona. In this paper, the activity of the Cremona psychiatric services is described, and the consequences of the reform law and the problems related to an hospital-based activity are emphasized. 相似文献
33.
Giovanni Melioli Editta Baldini Maria Cristina Mingari Andrea De Maria Mario Roberto Sertoli Fausto Badellino Pier Luigi Percivale Alessandra Catturich Sergio Bertoglio Dario Civalleri Leonardo Santi Lorenzo Moretta 《International journal of cancer. Journal international du cancer》1989,43(2):231-234
In the course of a phase I trial, in which recombinant IL-2 (rIL-2) was infused intraperitoneally (i.p.) in patients with peritoneal carcinomatosis, we evaluated the effect on "tumor-associated lymphocytes" (TAL) isolated from the ascitic fluid. No major changes in the percentages of cells expressing the CD3, CD4, CD8, Leu-7, OKM1 and WT-31 antigens were detected either in TAL or in peripheral blood lymphocytes (PBL) after 7 days of rIL-2 infusion. In contrast the percentages of TAL (but not PBL) expressing surface IL-2 receptor (Tac), or LAK-1 antigen were sharply increased. Analysis of cytolytic functions showed a potentiation of the lytic activity against natural-killer (NK) sensitive K562 target cells and the de novo appearance of lytic activity against fresh melanoma cells. In one patient IFN-gamma was detected in the ascitic fluid following rIL-2 infusion. T-cell clones derived from the patient were analyzed for the IFN-gamma production. While only approximately 40% of PB-derived control clones produced medium to low amounts of IFN-gamma, all of the TAL-derived clones produced medium to high amounts of the lymphokine. 相似文献
34.
Carmine M. Carapella Marco G. Paggi Fabio Cattani Giovanni B. Ciottoli Aristide Floridi Bruno Iandolo Laura Raus Antonio Riccio Antonio Caputo 《Journal of neuro-oncology》1989,7(1):103-108
Summary Up-to-date unsatisfactory results obtained in multimodality treatments of malignant glioma have prompted the research of new therapeutic modalities with unconventional modes of action. Lonidamine (LND) is a drug which reduces aerobic glycolytic activity in both human and experimental tumors. This effect mainly depends on the inhibition of mitochondrially-bound hexokinase (HK) which is present in large amounts in malignant cells. A Phase II study was conducted on patients with recurrent glioma; 12 patients were admitted to the study. Clinical side effects were moderate, necessitating a reduction of the dosage in only 1 case. The objective results were evaluated according to the indications of Levin. 2 responders and 3 cases of stable disease were observed out of 10 evaluable patients. The potential value of this new drug is discussed. 相似文献
35.
A hyperpolarization-activated chloride current in xenopus laevis oocytes under voltage-clamp 总被引:2,自引:0,他引:2
Antonio Peres Giovanni Bernardini 《Pflügers Archiv : European journal of physiology》1983,399(2):157-159
Voltage-clamp experiments have been performed on ovulated Xenopus laevis oocytes. Two kinds of oocytes were studied: mature oocytes presenting the white spot due to germinal vesicle breakdown (GVBD) were found to be essentially unexcitable; oocytes without the white spot appeared to possess ionic channels which open transiently on hyperpolarization. The current is carried by chloride ions and, in Holtfreter's solution, has a reversal potential at approximately - 15 mV. 相似文献
36.
Giordano-Lanza G Guerra G Tafuri D 《Italian journal of anatomy and embryology = Archivio italiano di anatomia ed embriologia》2002,107(4):215-223
Physical activity increases the work load of the heart. The adjustments of the heart depend on the quality and quantity of the work performed. These adjustments concern the function and the morphology of the cardiovascular system. It is important to underline that these adjustments are not permanent and can disappear when physical activity is stopped. In young subjects the risks are very few while the benefits may be shown on a better and more armonic body structure. In the elderly the benefits can be achieved with a lesser cost for submaximal activities, but the risks are of course more frequent due the possible onset of cardiovascular disease. It is important to correctly recognize the limits whitin which the physical activity can be allowed because beneficial. Echocardiography has given an important contribution to evaluate the morpho-functional adaptions of the athlete's heart. Similarly, it has proven useful in the detection of pathological cardiovascular modifications, asymptomatic or pausymptomatic, that do not allow certification to practise sport at agonistic levels. 相似文献
37.
Giammanco GM Vitale G Mansueto S Capra G Caleca MP Ammatuna P 《Journal of clinical microbiology》2005,43(12):6027-6031
A retrospective analysis by molecular-sequence-based techniques was performed to correctly identify the etiological agent of 24 Mediterranean spotted fever cases occurring in Western Sicily, Italy, from 1987 to 2001. Restriction analysis of a 632-bp PCR-amplified portion of the ompA gene allowed presumptive identification of five clinical isolates as belonging to Rickettsia conorii subsp. israelensis, the etiological agent of Israeli spotted fever (ISF). The remaining 19 rickettsial isolates were Rickettsia conorii subsp. conorii, the only pathogenic rickettsia of the spotted fever group reported in Italy until the present. Sequence analysis of the ompA gene confirmed the identification of all the R. conorii subsp. israelensis isolates and demonstrated that rickettsiosis caused by R. conorii subsp. israelensis can be traced back to 1991 in Sicily. The recorded clinical data of the five ISF patients support the idea that these strains could correlate to more-severe forms of human disease. Three of five patients experienced severe disease, and one of them died. 相似文献
38.
In this review we describe the developmental mechanisms involved in the making of a limb, by focusing on the nature and types of interactions of the molecules that play a part in the regulation of limb patterning and characterizing clinical conditions that are known to result from the abnormal function of these molecules. The latter subject is divided into sections dealing with syndromal and nonsyndromal deficiencies, polydactylies, and brachydactylies. Conditions caused by mutations in homeobox genes and fibroblast growth factors and their receptor genes are listed separately. Since the process of limb development has been conserved for more than 300 millions years, with all the necessary adaptive modifications occurring throughout evolution, we also take into consideration the evolutionary aspects of limb development in terms of genetic repertoire, molecular pathways, and morphogenetic events. 相似文献
39.
Early detection of negative BACTEC MGIT 960 cultures by PCR-reverse cross-blot hybridization assay 下载免费PDF全文
Romano L Sanguinetti M Posteraro B Ardito F Gesu G Schito AM Fadda G 《Journal of clinical microbiology》2002,40(9):3499-3501
We evaluated the efficacy of a PCR-reverse cross-blot hybridization assay, a test which permits identification of mycobacteria by means of species-specific probes and a Mycobacterium-specific probe, for early detection of negative BACTEC MGIT 960 mycobacterial cultures. Aliquots of 549 cultures were collected 7 days after the culture media were inoculated with various clinical specimens and tested with the molecular assay. PCR results were compared to those obtained at the end times with the BACTEC MGIT 960 system. Of the 549 specimens analyzed, 484 were found to be negative and 64 were found positive by both methods; one specimen, found to be positive by the BACTEC MGIT 960 system, was identified as negative by the molecular assay. In view of its high negative predictive value (99.8%), the PCR-reverse cross-blot hybridization assay appears to be a valid tool for early detection of negative BACTEC MGIT 960 cultures. 相似文献
40.
Jeannin P Magistrelli G Herbault N Goetsch L Godefroy S Charbonnier P Gonzalez A Delneste Y 《European journal of immunology》2003,33(2):326-333
Outer membrane protein A (OmpA) is a class of bacterial cell wall protein that is immunogenic without adjuvant. As specific immune responses are initiated in the lymph nodes (LN, we analyzed the effect of the OmpA from Klebsiella pneumoniae (KpOmpA) onchemokine/ chemokine receptor expression by APC and on cell migration to the LN. Upon contact with KpOmpA, human immature DC and macrophages acquire CCR7 expression and responsiveness to CCL21. In parallel, CCR1 and CCR5 expression is down-regulated and CXCL8, CCL2, CCL3 and CCL5 production is up-regulated. Mice injected subcutaneously with KpOmpA present a transient inflammatory reaction at the site of injection accompanied by an enlargement of the draining LN with a higher proportion of DC and macrophages. Lastly, when exposed to KpOmpA prior injection, DC but not macrophages migrate to the draining LN. In conclusion, KpOmpA confers a migratory phenotype to DC and triggers their migration to the regional LN. This property contributes to explain how innate cells initiate adaptive immune response upon recognition of conserved bacterial components and also why OmpA is immunogenic in the absence of adjuvant. 相似文献