全文获取类型
收费全文 | 2349207篇 |
免费 | 175045篇 |
国内免费 | 3326篇 |
专业分类
耳鼻咽喉 | 32122篇 |
儿科学 | 75988篇 |
妇产科学 | 62742篇 |
基础医学 | 348509篇 |
口腔科学 | 63707篇 |
临床医学 | 211652篇 |
内科学 | 457719篇 |
皮肤病学 | 51763篇 |
神经病学 | 185534篇 |
特种医学 | 88108篇 |
外国民族医学 | 489篇 |
外科学 | 354237篇 |
综合类 | 47571篇 |
现状与发展 | 12篇 |
一般理论 | 850篇 |
预防医学 | 183012篇 |
眼科学 | 54365篇 |
药学 | 175283篇 |
11篇 | |
中国医学 | 4575篇 |
肿瘤学 | 129329篇 |
出版年
2021年 | 19007篇 |
2019年 | 19581篇 |
2018年 | 27108篇 |
2017年 | 20402篇 |
2016年 | 22796篇 |
2015年 | 25699篇 |
2014年 | 36169篇 |
2013年 | 54065篇 |
2012年 | 74813篇 |
2011年 | 79537篇 |
2010年 | 47137篇 |
2009年 | 44656篇 |
2008年 | 74747篇 |
2007年 | 79630篇 |
2006年 | 80417篇 |
2005年 | 77908篇 |
2004年 | 74474篇 |
2003年 | 71780篇 |
2002年 | 69474篇 |
2001年 | 108806篇 |
2000年 | 111532篇 |
1999年 | 93548篇 |
1998年 | 27013篇 |
1997年 | 23672篇 |
1996年 | 24081篇 |
1995年 | 22735篇 |
1994年 | 20905篇 |
1993年 | 19727篇 |
1992年 | 72050篇 |
1991年 | 70119篇 |
1990年 | 68421篇 |
1989年 | 65700篇 |
1988年 | 60334篇 |
1987年 | 59174篇 |
1986年 | 55256篇 |
1985年 | 53042篇 |
1984年 | 39341篇 |
1983年 | 33421篇 |
1982年 | 19881篇 |
1979年 | 35894篇 |
1978年 | 25677篇 |
1977年 | 21248篇 |
1976年 | 20346篇 |
1975年 | 21840篇 |
1974年 | 26169篇 |
1973年 | 24830篇 |
1972年 | 23214篇 |
1971年 | 22056篇 |
1970年 | 20270篇 |
1969年 | 19331篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
M. D. Mashkovskii V. A. Parshin R. B. Parimbetova 《Bulletin of experimental biology and medicine》1997,123(3):257-259
It is found that the cholinomimetic aceclidine stimulates learning and memory processes and exerts antiamnestic effect in
rats with conditioned avoidance reaction. The effect of aceclidine is not inferior to that of amiridin and surpasses that
of physostigmine.
Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 3, pp. 296–298, March, 1997 相似文献
992.
Engineering human immunodeficiency virus 1 protease heterodimers as macromolecular inhibitors of viral maturation. 总被引:3,自引:0,他引:3
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
F McPhee A C Good I D Kuntz C S Craik 《Proceedings of the National Academy of Sciences of the United States of America》1996,93(21):11477-11481
Dimerization of human immunodeficiency virus type 1 protease (HIV-1 PR) monomers is an essential prerequisite for viral proteolytic activity and the subsequent generation of infectious virus particles. Disruption of the dimer interface inhibits this activity as does formation of heterodimers between wild-type and defective monomers. A structure-based approach was used to identify amino acid substitutions at the dimer interface of HIV-1 PR that facilitate preferential association of heterodimers and inhibit self-association of the defective monomers. Expression of the designed PR monomers inhibits activity of wild-type HIV-1 PR and viral infectivity when assayed in an ex vivo model system. These results show that it is possible to design PR monomers as macromolecular inhibitors that may provide an alternative to small molecule inhibitors for the treatment of HIV infection. 相似文献
993.
S. NIKOLOVSKI D. L. FAULKNER T. N. PALMER P. A. FOURNIER 《Acta physiologica (Oxford, England)》1996,157(4):427-434
During recovery from high intensity exercise, substantial and rapid muscle glycogen repletion from endogenous carbon sources is reported in a variety of vertebrate species, the rat being the only reported exception. The major aim of this study was to re-examine the process of glycogen repletion during recovery from high intensity exercise in the rat. In response to 3 min of vigorous swimming, muscle glycogen concentrations decrease markedly from initial levels of 20.2±1.5 and 21.2±0.9 μmol g-1 to 6.4±1.1 and 7.9±1.4 μmol g-1 in the tibialis anterior and plantaris muscles respectively. The equivalent of 58% of the glycogen carbons mobilized during exercise by the plantaris and 73% of that mobilized by the tibialis anterior muscle is repleted within 1 h following exercise. Using the hepatectomized rat as experimental model, a secondary aim of the study was to evaluate whether the liver is essential for the repletion of muscle glycogen. Although the absence of significant differences in the magnitude of post-exercise muscle glycogen repletion between sham-operated and hepatectomized rats suggests that the resynthesis of muscle glycogen can take place in the absence of hepatic gluconeogenesis, the present study identifies several limitations in the use of acute hepatectomy. Overall, the present study indicates that, in contrast to published views, the rat resembles other vertebrates in that it can support extensive muscle glycogen repletion from endogenous carbon sources during the recovery phase following high intensity exercise. 相似文献
994.
Paul P. W. van Buul Iris M. Zandman Mira Grigorova Jan J. W. A. Boei Adayapalam T. Natarajan 《Chromosome research》1995,3(7):427-432
The efficiency of two methods of detection of translocations induced in mouse stem cell spermatogonia by X-ray doses of 2, 5 and 7 Gy was compared: classical multivalent analysis at diakinesis-metaphase I of meiosis and observation via fluorescencein situ hybridization analysis of mitotic or meiotic stages. Specific DNA libraries for chromosomes 1, 11 and 13 were used. The results obtained indicate that (a) chromosomes 1, 11 and 13 are more involved in multivalent formation than expected on the basis of DNA content and (b) if the mitotic FISH analysis data are corrected for the observed over-representation, the frequencies of induced translocations are similar to those recorded in the classical multivalent studies, suggesting equal scoring efficiencies in both systems. 相似文献
995.
996.
J.I. Smedberg E. Lothigius I. Bodin A. Frykholm K. Nilner 《Clinical oral implants research》1993,4(1):39-46
In order to satisfy the need to restore the aesthetics, phonetics and comfort and to facilitate optimal hygiene procedures, 20 edentulous patients were treated with a new concept of overdenture therapy on implants ad modum Brånemark. After 24±3.5 months the patients were re‐examined. They were asked to answer a questionnaire and use a Visual Analogue Scale (VAS) to give their opinion on the prosthetic treatment. The results indicate that an implant‐retained overdenture in the maxilla with this design can satisfy the patients needs in aesthetics, phonetics and comfort and can 1 facilitate oral hygiene measures. 相似文献
997.
P. Lamesch A. Lamesch 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》1993,378(3):171-177
We report on the case of a 6-year-old girl admitted as an emergency with an acute abdomen with the diagnosis of peritonitis; clinical examination under anesthesia revealed the presence of an abdomino-pelvic mass. Laparotomy confirmed the diagnosis of torsion of an ectopic spleen. Splenectomy was required because the spleen was gangrenous. A review of the literature from 1896 to 1990 revealed reports of 74 cases. Epidemiology, etiology, pathophysiology, the diagnostic and therapeutic problems are discussed.
Ektopische Milz beim Kind: Fallbericht und Literaturübersicht 1896–1990
Zusammenfassung Anhand eines Fallberichtes und einer Literaturübersicht über 74 Fälle werden Epidemiologie, Ätiologie, Pathophysiologie, Diagnostik und Therapie der im Kindesalter sehr seltenen ektopen Milz besprochen. Die klinischen Zeichen reichen von unspezifischen abdominellen Beschwerden bis hin zum Vollbild eines akuten Abdomen (50%). Die praeoperative Diagnostik richtet sich nach Klinik, Abdomenleeraufnahme und Sonographie, evtl. Computertomographie. Aufgrund der hohen Torsionsraten besteht generell eine Operationsindikation, wobei die Entscheidung über Splenopexie oder Splenektomie sich an dem Lokalbefund orientieren sollte. Zur Splenopexie wurden mehrere Techniken mit gleich guten Resultaten angegeben.相似文献
998.
The objectives of this study were to investigate (1) changes in consumption of alcohol among pregnant women over a period of 5 years (1984/85–1990), (2) changes of attitudes towards drinking during pregnancy in the general population over the same period of time, and (3) possible connections between (1) and (2). The investigation was designed as a cross-sectional study. Our subjects were two representative samples of pregnant women in Oslo, n = 577 and 425, and two representative samples of the Norwegian population, n = 1004 and 1204. The main outcome measures were a self-completed questionnaire for the pregnant women and a personal interview for the general population sample. There was a significant reduction (50% decrease) in alcohol consumption among the second cohort of pregnant women compared with the first. Furthermore, we found an increase during the 5-year period in the number of persons with a restrictive attitude towards alcohol use during pregnancy. There seems to be a connection between these two phenomena, but with our present state of knowledge it is hard to say anything about the causal relationship between them. 相似文献
999.
T F Kruger J P Van der Merwe H J Odendaal F S Stander G M Grobler V A Hulme E L Erasmus K Coetzee M L Windt Y Swart 《Suid-Afrikaanse tydskrif vir geneeskunde》1990,77(12):634-636
The results of the in vitro fertilisation programme at Tygerberg Hospital for the period April 1983 to January 1988 are presented. Of the 1117 laparoscopies performed, 825 patients reached the transfer stage. A live-birth rate of 9.3% was achieved. The pregnancy rate after transfer of 4 embryos was 25.9% compared with 15.4% after 2 embryos and 10.8% after 3 embryos (P = less than 0.0001). The multiple pregnancy rate was 2.8% in the group receiving 2 embryos and 11.7% and 10.4% in those receiving 3 and 4 embryos, respectively. Of the 77 successful pregnancies (90 babies), 1 baby died at 34 weeks' gestation as the result of abruptio placentae due to preeclampsia and 1 cot death occurred. The only congenital abnormality encountered was a cleft palate. 相似文献
1000.
S.A. GEORGE D.J. BILSLAND N.J. WAINWRIGHT J. FERGUSON 《The British journal of dermatology》1993,128(3):301-305
Despite a widely held belief that the use of emollients prior to broad-band UVB irradiation accelerates clearance of psoriasis, only one single-blind controlled study exists in support of this. No similar study has been carried out with photochemotherapy (PUVA) or narrow-band UVB (311–313 nm) phototherapy. As some emollients absorb UV radiation, and thereby inhibit psoriasis clearance, there is a need to identify emollients suitable for pre-irradiation use. Coconut oil may be useful in this respect. In two randomized groups of patients with chronic plaque psoriasis undergoing either routine PUVA(n=14) or narrow-band UVB phototherapy (n=15), a single-blind controlled (half-body) study was undertaken to assess the died of pre-irradiation application of coconut oil. Patients were given PUVA twice weekly, or TL-01 therapy thrice weekly. The initial UV dose was 70% of previously determined minimal phototoxic (MPD) or minimal erythema doses (MED), with 40% incremental steps at each visit (reduced if adverse effects occurred). Psoriasis severity was scored on each side after every three treatments. No significant acceleration of psoriasis clearance was seen in either group. We do not, therefore, recommend the routine use of emollients prior to PUVA or TL-01 therapy when using near erythemogenic irradiation regimens. 相似文献