全文获取类型
收费全文 | 2360878篇 |
免费 | 179635篇 |
国内免费 | 5085篇 |
专业分类
耳鼻咽喉 | 32459篇 |
儿科学 | 74767篇 |
妇产科学 | 65959篇 |
基础医学 | 337495篇 |
口腔科学 | 69624篇 |
临床医学 | 210678篇 |
内科学 | 456236篇 |
皮肤病学 | 52084篇 |
神经病学 | 185122篇 |
特种医学 | 90807篇 |
外国民族医学 | 408篇 |
外科学 | 361586篇 |
综合类 | 58633篇 |
现状与发展 | 6篇 |
一般理论 | 753篇 |
预防医学 | 178979篇 |
眼科学 | 56751篇 |
药学 | 174742篇 |
7篇 | |
中国医学 | 5574篇 |
肿瘤学 | 132928篇 |
出版年
2018年 | 25181篇 |
2017年 | 19341篇 |
2016年 | 21426篇 |
2015年 | 24572篇 |
2014年 | 34483篇 |
2013年 | 50963篇 |
2012年 | 69910篇 |
2011年 | 73684篇 |
2010年 | 43456篇 |
2009年 | 40638篇 |
2008年 | 68804篇 |
2007年 | 73712篇 |
2006年 | 74038篇 |
2005年 | 71286篇 |
2004年 | 69111篇 |
2003年 | 65974篇 |
2002年 | 63664篇 |
2001年 | 114741篇 |
2000年 | 117397篇 |
1999年 | 97840篇 |
1998年 | 26832篇 |
1997年 | 23756篇 |
1996年 | 23671篇 |
1995年 | 22633篇 |
1994年 | 21004篇 |
1993年 | 19596篇 |
1992年 | 76371篇 |
1991年 | 74039篇 |
1990年 | 71687篇 |
1989年 | 69021篇 |
1988年 | 63578篇 |
1987年 | 62261篇 |
1986年 | 58776篇 |
1985年 | 56229篇 |
1984年 | 42117篇 |
1983年 | 35931篇 |
1982年 | 21092篇 |
1981年 | 19078篇 |
1979年 | 39104篇 |
1978年 | 27489篇 |
1977年 | 23329篇 |
1976年 | 21631篇 |
1975年 | 23082篇 |
1974年 | 28186篇 |
1973年 | 27162篇 |
1972年 | 25559篇 |
1971年 | 23712篇 |
1970年 | 22267篇 |
1969年 | 21084篇 |
1968年 | 19431篇 |
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
961.
Doing it right the first time: quality improvement and the contaminant blood culture. 总被引:5,自引:3,他引:2
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
F I Weinbaum S Lavie M Danek D Sixsmith G F Heinrich S S Mills 《Journal of clinical microbiology》1997,35(3):563-565
The aim of the project was to determine whether the rate of contaminant blood cultures could be reduced by using a team of dedicated phlebotomists. Comparisons were made between adult patients requiring blood cultures for suspected bacteremia on medical and surgical units before and after the introduction and withdrawal of a dedicated blood culture team. The results showed that a significant reduction in the contaminant blood culture rate was achieved by the blood culture team (P < 0.001; chi(2) test). Therefore, in our experience, the rate of contaminant blood cultures can be reduced in a teaching hospital by using a team of dedicated phlebotomists. Calculations made with our data and those published by others suggest that cost savings from reducing false-positive blood cultures are greater than the cost of the blood culture team. 相似文献
962.
Beta2-glycoprotein I-dependent anticardiolipin antibody in early recurrent spontaneous abortion 总被引:1,自引:1,他引:0
Maejima M; Fujii T; Okai T; Kozuma S; Shibata Y; Taketani Y 《Human reproduction (Oxford, England)》1997,12(10):2140-2142
The objective of this study was to assess the clinical significance of
autoimmune anticardiolipin antibody that can react with cardiolipin only in
the presence of beta2-glycoprotein I (beta2-glycoprotein I- dependent
anticardiolipin antibody) in the pathogenesis of early recurrent abortion.
A total of 72 early recurrent spontaneous aborters and 175 normal healthy
women were analysed for the occurrence of beta2- glycoprotein I-dependent
anticardiolipin antibody in serum samples by an enzyme-linked immunosorbent
assay specific for the detection of beta2-glycoprotein I-dependent
anticardiolipin antibody. The incidence of beta2-glycoprotein I-dependent
anticardiolipin antibody in the early recurrent spontaneous aborters was
essentially the same as that of normal women. Thus, the beta2-glycoprotein
I-dependent anticardiolipin antibody seemed to have little, if any,
implication in the pathogenesis of early recurrent spontaneous abortion.
相似文献
963.
964.
965.
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
966.
967.
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
968.
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
969.
H. D. Tagare K. W. Elder D. M. Stoner R. M. Patterson C. L. Nicodemus S. F. Viegas Dr. G. R. Hillman 《Annals of biomedical engineering》1993,21(6):715-726
The carpal regions of ten cadaver extremities were imaged by CT. The images were combined into a 3-dimensional model of the
carpus using a technique based on a dynamic programming algorithm to find an optimal estimate of the location of the bone
boundaries in the CT images. The resulting set of surface points on each bone was used to compute volumes and principal and
antipodal axes for the bones. A spatial coordinate system was established based on the positions of the centroids of three
bones in the distal carpal row. The angular orientations of all carpal bones were determined with respect to this system.
The principal axes for the same bone among ten wrist specimens proved to be more widely dispersed than the antipodal axes
for the same bones. The antipodal axes also correspond more closely to an intuitive notion of the “longest axis” of the bones.
We conclude that the antipodal axis is a more reliable and useful measure of bone orientation than the principal axis. 相似文献
970.
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