全文获取类型
收费全文 | 25244篇 |
免费 | 1846篇 |
国内免费 | 82篇 |
专业分类
耳鼻咽喉 | 379篇 |
儿科学 | 705篇 |
妇产科学 | 538篇 |
基础医学 | 3124篇 |
口腔科学 | 277篇 |
临床医学 | 2592篇 |
内科学 | 5485篇 |
皮肤病学 | 489篇 |
神经病学 | 2260篇 |
特种医学 | 1206篇 |
外科学 | 4123篇 |
综合类 | 258篇 |
一般理论 | 23篇 |
预防医学 | 1779篇 |
眼科学 | 412篇 |
药学 | 1781篇 |
中国医学 | 28篇 |
肿瘤学 | 1713篇 |
出版年
2023年 | 294篇 |
2022年 | 557篇 |
2021年 | 1130篇 |
2020年 | 632篇 |
2019年 | 948篇 |
2018年 | 1054篇 |
2017年 | 712篇 |
2016年 | 741篇 |
2015年 | 927篇 |
2014年 | 1180篇 |
2013年 | 1465篇 |
2012年 | 2125篇 |
2011年 | 2158篇 |
2010年 | 1150篇 |
2009年 | 915篇 |
2008年 | 1419篇 |
2007年 | 1433篇 |
2006年 | 1335篇 |
2005年 | 1190篇 |
2004年 | 1059篇 |
2003年 | 905篇 |
2002年 | 811篇 |
2001年 | 268篇 |
2000年 | 187篇 |
1999年 | 218篇 |
1998年 | 149篇 |
1997年 | 115篇 |
1996年 | 114篇 |
1995年 | 86篇 |
1994年 | 65篇 |
1993年 | 60篇 |
1992年 | 120篇 |
1991年 | 104篇 |
1990年 | 109篇 |
1989年 | 109篇 |
1988年 | 80篇 |
1987年 | 89篇 |
1986年 | 81篇 |
1985年 | 85篇 |
1984年 | 67篇 |
1983年 | 58篇 |
1982年 | 55篇 |
1981年 | 63篇 |
1980年 | 43篇 |
1979年 | 53篇 |
1978年 | 48篇 |
1974年 | 37篇 |
1973年 | 48篇 |
1972年 | 51篇 |
1970年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Glucose Ingestion Attenuates Interleukin-6 Release from Contracting Skeletal Muscle in Humans 总被引:8,自引:1,他引:8
Mark A. Febbraio Adam Steensberg Charlotte Keller Rebecca L. Starkie Henning B. Nielsen Peter Krustrup Peter Ott Niels H. Secher Bente K. Pedersen 《The Journal of physiology》2003,549(2):607-612
To examine whether glucose ingestion during exercise affects the release of interleukin-6 (IL-6) from the contracting limb, seven men performed 120 min of semi-recumbent cycling on two occasions while ingesting either 250 ml of a 6.4 % carbohydrate (GLU trial) or sweet placebo (CON trial) beverage at the onset of, and at 15 min intervals throughout, exercise. Muscle biopsies obtained before and immediately after exercise were analysed for glycogen and IL-6 mRNA expression. Blood samples were simultaneously obtained from a brachial artery and a femoral vein prior to and during exercise and leg blood flow was measured by thermodilution in the femoral vein. Net leg IL-6 release, and net leg glucose and free fatty acid (FFA) uptake, were calculated from these measurements. The arterial IL-6 concentration was lower ( P < 0.05 ) after 120 min of exercise in GLU, but neither intramuscular glycogen nor IL-6 mRNA were different when comparing GLU with CON. However, net leg IL-6 release was attenuated ( P < 0.05 ) in GLU compared with CON. This corresponded with an enhanced ( P < 0.05 ) glucose uptake and a reduced ( P < 0.05 ) FFA uptake in GLU. These results demonstrate that glucose ingestion during exercise attenuates leg IL-6 release but does not decrease intramuscular expression of IL-6 mRNA. 相似文献
93.
Torbicki A 《Pneumonologia i alergologia polska》2003,71(11-12):543-549
94.
Differentiation of Cucumber mosaic virus isolates by hybridization to oligonucleotides in a microarray format 总被引:5,自引:0,他引:5
Deyong Z Willingmann P Heinze C Adam G Pfunder M Frey B Frey JE 《Journal of virological methods》2005,123(1):101-108
A system for microarrays was developed to detect and differentiate Cucumber mosaic virus (CMV) serogroups and subgroups. The coat protein genes of 14 different isolates were amplified using cy3-labelled generic but species-specific primers. These amplicons were hybridized against a set of five different serotype and subgroup specific 24-mer oligonucleotides bound to an aldehyde-coated glass slide via an aminolinker. The results of the hybridization revealed that the method allowed a clear differentiation of the 14 different CMV isolates into the serogroupes 1 and 2, and in addition was able to assign 9 out of 10 different serogroup 1 isolates correctly into subgroups 1a and 1b. This differentiation was not possible by RFLP analysis with the restriction enzyme MspI. The use of amplicons larger than 700 base pairs and their successful differentiation by hybridization to specific oligonucleotides opens avenues to highly parallel, yet sensitive assays for plant viruses. 相似文献
95.
Houghton FD Hawkhead JA Humpherson PG Hogg JE Balen AH Rutherford AJ Leese HJ 《Human reproduction (Oxford, England)》2002,17(4):999-1005
BACKGROUND: IVF is limited by low success rates and a confounding high multiple birth rate contributing to prematurity, increased neonatal mortality and child handicap. These problems could be overcome if single embryos of known developmental competence could be selected for transfer on day 2/3 of development, but current methods, which rely on morphological appearance, are poor predictors of viability. METHODS: We have measured non-invasively the depletion/appearance (i.e. turnover) of a physiological mixture of 18 amino acids by single human embryos during in-vitro culture using high performance liquid chromatography. RESULTS: From the time of transfer (day 2/3), embryos with future competence to develop to the blastocyst stage (day 5/6) exhibit amino acid flux patterns distinct from those of embryos with similar morphological appearance which arrest. Significantly, the profiles of Ala, Arg, Gln, Met and Asn flux predict blastocyst potentiality at >95%. The amino acid most consistently depleted throughout development by those embryos which form blastocysts was leucine. Of the amino acids which were produced, the most striking was alanine, which appeared in increasing amounts throughout development. CONCLUSIONS: Non-invasive amino acid profiling has the potential to select developmentally competent single embryos for transfer, thereby increasing the success rate and eliminating multiple births in IVF. 相似文献
96.
Kinetics of the humoral and cellular immune response of guinea pigs after injection of the synthetic adjuvant N-acetylmuramyl L-alanyl-D-isoglutamine: comparison with Freund complete adjuvant. 下载免费PDF全文
We studied the time course of humoral and cellular immunity of guinea pigs injected with the synthetic adjuvant N-acetylmuramyl L-alanyl-D-isoglutamine (MDP Pasteur, 10 microgram) in Freund incomplete adjuvant; the kinetics were compared with those obtained with Freund complete adjuvant (50 microgram of whole Mycobacterium butyricum). The antibody response to ovalbumin was faster and higher with MDP, but dropped sooner to a low level; the secondary response was, however, again higher for MDP than for Freund complete adjuvant. Cellular immunity, as measured by delayed hypersensitivity, and migration inhibition factor production werepositive for both adjuvants. The same response was followed in animals injected with MDPA, the nonamidated analog of MDP; the same kinetics as for Freund incomplete adjuvant were obtained for the primary response, but the secondary response was stronger and gave a positive delayed hypersensitivity reaction. 相似文献
97.
Summary 100 stool extracts from patients with poliomyelitis or from individuals after oral poliomyelitis vaccination were inoculated simultaneously into HeLa, monkey kidney, and human thyroid cultures. In most cases (88 times) a cytopathic effect was seen in all three cultures. Failures were most frequently encountered in thyroid, rarely in monkey kidney cells. They were due either to thyroid culture lots with reduced viral susceptibility or to small amounts of virus in the stool specimens. No qualitative difference was found in the host range of individual virus strains. With attenuated viruses the cytopathic effect in HeLa cells as a rule was delayed for several days.
Die Untersuchungen wurden mit Unterstützung der Deutschen Vereinigung zur Bekmpfung der Kinderlähmung e.V. durchgeführt.
Wir danken Herrn Privatdoz. Dr. F.Müller, Düsseldorf, für die freundliche überlassung einiger virushaltiger Stuhlproben. Herr Dr. A. R.Ababio, Homburg, war uns bei der Beschaffung von Stuhlproben nach oraler Poliomyelitisimpfung behilflich. Wir danken schließlich Fräulein E.Baschleben, Frau H.Gelderblom, Frau H.Kaiser und Fräulein I.Lamy für ihre Hilfe bei den Untersuchungen. 相似文献
Die Untersuchungen wurden mit Unterstützung der Deutschen Vereinigung zur Bekmpfung der Kinderlähmung e.V. durchgeführt.
Wir danken Herrn Privatdoz. Dr. F.Müller, Düsseldorf, für die freundliche überlassung einiger virushaltiger Stuhlproben. Herr Dr. A. R.Ababio, Homburg, war uns bei der Beschaffung von Stuhlproben nach oraler Poliomyelitisimpfung behilflich. Wir danken schließlich Fräulein E.Baschleben, Frau H.Gelderblom, Frau H.Kaiser und Fräulein I.Lamy für ihre Hilfe bei den Untersuchungen. 相似文献
98.
99.
Splenic metastasis from lung cancer is a rare clinical event, most often diagnosed at the time of an autopsy. We report a case of a 68 year old man with splenic metastasis from the primary lung cancer. Staging procedures before the resection of the primary lung tumor detected the splenic lesion. Upper left lobectomy and splenectomy were done by the left postero-lateral thoracotomy with phrenotomy. The rarity of solitary spleen metastasis from lung cancer and the treatment are discussed. 相似文献
100.
E. Henze S. Männer M. Clausen P. Malfertheiner D. Hellwig H. Ditschuneit H. Kornhuber W. E. Adam 《Journal of molecular medicine (Berlin, Germany)》1988,66(8):332-336
Summary It was the purpose of this study to evaluate the diagnostic usefulness of an oral absorption test using nonlabeled Vit B12 suggested by a commercial distributor as an alternative for the more expensive Schilling test (ST). Plasma levels of Vit B12 were measured with a commercial kit before and 4 h after oral administration of 1 mg Vit B12 in 32 normals, in 16 patients with normal ST, and in 14 patients with abnormal ST for determination of sensitivity and specificity with the ST as golden standard. In normals, a mean of 767±404 pg/ml before and 1096±776 pg/ml after oral Vit B12 with a mean increase of 331±453 pg/ml was measured. Because of the obvious large variation, no meaningful range for normal absorption could be established. In the two patient subsets, there was no Gaussian distribution of the results, with a meridian of Vit B12 increase after absorption of 142 pg/ml, range 27–2668 pg/ml, in the group with normal ST and a meridian of 244 pg/ml ranging from 40 to 2453 pg/ml in the group with abnormal ST. Statistical nonparametric analysis did not reveal any difference between the two groups. Assuming a minimum required increase of 100 pg/ml, as suggested by the kit distributor, a sensitivity of only 27% and a specificity of 75% was obtained. The lack of any diagnostic value of this approach might be caused by the known nonintrinsic-factor mediated absorption of approximately 1% of any B12 given orally even in complete intrinsic factor deficiency and by the relatively large amount of oral Vit B12 needed for a cold absorption test. The latter can, thus, not replace the Schilling test.Abbreviations Vit B12
Vitamin B12 相似文献