全文获取类型
收费全文 | 415篇 |
免费 | 33篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 34篇 |
妇产科学 | 8篇 |
基础医学 | 68篇 |
口腔科学 | 2篇 |
临床医学 | 23篇 |
内科学 | 99篇 |
皮肤病学 | 7篇 |
神经病学 | 15篇 |
特种医学 | 102篇 |
外科学 | 32篇 |
综合类 | 3篇 |
预防医学 | 38篇 |
药学 | 12篇 |
肿瘤学 | 13篇 |
出版年
2022年 | 6篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2018年 | 7篇 |
2017年 | 3篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 8篇 |
2013年 | 4篇 |
2012年 | 7篇 |
2011年 | 9篇 |
2010年 | 5篇 |
2009年 | 10篇 |
2008年 | 6篇 |
2007年 | 12篇 |
2006年 | 7篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 14篇 |
2001年 | 13篇 |
2000年 | 10篇 |
1999年 | 7篇 |
1998年 | 11篇 |
1997年 | 10篇 |
1996年 | 15篇 |
1995年 | 14篇 |
1994年 | 12篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1990年 | 5篇 |
1989年 | 12篇 |
1988年 | 12篇 |
1987年 | 19篇 |
1986年 | 12篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 12篇 |
1979年 | 14篇 |
1978年 | 4篇 |
1977年 | 12篇 |
1976年 | 6篇 |
1972年 | 4篇 |
1968年 | 6篇 |
1966年 | 3篇 |
1965年 | 3篇 |
1939年 | 7篇 |
排序方式: 共有457条查询结果,搜索用时 0 毫秒
1.
2.
3.
Anderson RA; Evans LW; Irvine DS; McIntyre MA; Groome NP; Riley SC 《Human reproduction (Oxford, England)》1998,13(12):3319-3325
Follistatin is a binding protein for the activin and inhibin family of
hormones, regulating their biological activity. In the male reproductive
tract, the interaction of these factors is likely to be involved in the
regulation of the proliferation of several cell types. We have investigated
the presence of follistatin and activin A in seminal plasma using specific
immunoassays and have localized follistatin and activin/inhibin subunits in
the adult human testis, prostate and seminal vesicle to establish their
likely sources. High concentrations of immunoreactive follistatin were
present in seminal plasma in normal men (mean 97.9 ng/ml; 1.43 ng/ml in
peripheral plasma) and were similar in men with oligo/azoospermia and
following vasectomy. Follistatin immunoreactivity was localized to both
Leydig and Sertoli cells of the testis, and to epithelial cells of the
prostate gland and seminal vesicle, which are likely to be the predominant
sources of the hormone in seminal plasma. Activin A was also present in
seminal plasma in normal men but was undetectable following vasectomy, thus
deriving from the testis. Consistent with this finding, the betaA-subunit
was immunolocalized in Sertoli and Leydig cells but was not present in
seminal vesicle or prostate gland. The functional significance of the high
concentrations of follistatin secreted into seminal plasma by the prostate
gland and/or seminal vesicle is uncertain, but they may regulate the
biological activity of testis-derived activin A and inhibin B.
相似文献
4.
5.
Stimulation of protective antibodies against type Ia and Ib group B streptococci by a type Ia polysaccharide-tetanus toxoid conjugate vaccine. 总被引:6,自引:6,他引:6 下载免费PDF全文
M R Wessels L C Paoletti A K Rodewald F Michon J DiFabio H J Jennings D L Kasper 《Infection and immunity》1993,61(11):4760-4766
Antisera elicited by type Ia group B streptococci (GBS) contain antibodies that react with both type Ia and type Ib strains. Previous studies suggested that antibodies elicited by type Ia organisms recognized a carbohydrate antigen or epitope common to Ia and Ib strains. We now report the synthesis and immunogenicity testing of a type Ia polysaccharide-tetanus toxoid (Ia-TT) conjugate vaccine. Ia-TT elicited type Ia polysaccharide-specific immunoglobulin G antibodies in all three of the rabbits inoculated. In competitive enzyme-linked immunosorbent assay, these antibodies reacted with high affinity to type Ia polysaccharide and with lower affinity to the structurally related GBS type Ib polysaccharide. Despite the lower binding affinity of the Ia-TT-induced antibodies for the type Ib polysaccharide, Ia-TT antiserum opsonized not only type Ia GBS but also type Ib GBS for killing by human blood leukocytes. Ia-TT antiserum was also evaluated in a mouse model designed to test the efficacy of maternal antibodies in protecting neonates against GBS infection. Pups born to dams that had received Ia-TT antiserum were protected against lethal challenge with either type Ia or Ib GBS. These studies using a polysaccharide-protein conjugate as an immunogen support the view that the carbohydrate immunodeterminant recognized on Ib strains by Ia antisera is a common epitope contained within the structurally related Ia and Ib capsular polysaccharides. Although antibodies elicited by Ia-TT had protective activity against both Ia and Ib strains, these antibodies reacted with lower affinity to Ib than to Ia polysaccharide. 相似文献
6.
7.
A longitudinal study of maternal serum inhibin-A, inhibin-B, activin-A, activin-AB, pro-alphaC and follistatin during pregnancy 总被引:6,自引:1,他引:6
Fowler PA; Evans LW; Groome NP; Templeton A; Knight PG 《Human reproduction (Oxford, England)》1998,13(12):3530-3536
Maternal serum concentrations of inhibin-A, inhibin-B, activin-A,
activin-AB, pro-alphaC-related inhibin forms, total follistatin, steroids
and gonadotrophins were measured longitudinally in six normal singleton
pregnancies. Maternal venous blood was collected randomly during a
spontaneous follicular phase prior to donor insemination, at 5, 7, 9, 11,
16, 20, 24, 28, 32 and 36 weeks after the first missed menses and in the
early puerperium. Steroid and gonadotrophin profiles conformed to previous
reports. While at week 5 of gestation inhibin-A, activin-A and follistatin
concentrations were similar to those at the follicular phase, all three
increased progressively (P < 0.001) to maximal concentrations in week
36: approximately 48-fold (3740 +/- 1349 ng inhibin-A/ml), approximately
22-fold (6109 +/- 1443 ng activin-A/ml) and approximately 10-fold (3563 +/-
418 ng follistatin/ml) higher. Pro- alphaC concentrations reached a maximum
in weeks 5 (approximately 5- fold, P < 0.001) and 36 (1027 +/- 174
pg/ml, P < 0.01). Inhibin-B (71 +/- 23 pg/ml prior to pregnancy) was
undetectable (<12 pg/ml) between week 5-16 of gestation but increased
slightly in the third trimester (26 +/- 7 pg/ml in week 36). Activin-AB was
undetectable throughout pregnancy. Post-partum concentrations of inhibin-A
(41 +/- 12 ng/ml), inhibin-B (<12 pg/ml), activin-A (950 +/- 149 pg/ml),
pro-alphaC (128 +/- 22 pg/ml) and follistatin (990 +/- 79 ng/ml) were
substantially lower than at week 36 of gestation. The activin-A:follistatin
ratio increased from 0.5 in week 5 to 1.8 in week 36, suggesting that more
free activin-A is available in the maternal circulation during late
pregnancy.
相似文献
8.
Symptomatic peripheral arterial disease: the value of a validated questionnaire and a clinical decision rule 下载免费PDF全文
Bianca LW Bendermacher Joep AW Teijink Edith M Willigendael Marie-Louise Bartelink Harry R Büller Ron JG Peters Jelis Boiten Machteld Langenberg Martin H Prins 《The British journal of general practice》2006,56(533):932-937
BACKGROUND: If a validated questionnaire, when applied to patients reporting with symptoms of intermittent claudication, could adequately discriminate between those with and without peripheral arterial disease, GPs could avoid the diagnostic measurement of the ankle brachial index. AIM: To investigate the Edinburgh Claudication Questionnaire (ECQ) in general practice and to develop a clinical decision rule based on risk factors to enable GPs to easily assess the likelihood of peripheral arterial disease. DESIGN OF STUDY: An observational study. SETTING: General practice in The Netherlands. METHOD: This observational study included patients of > or =55 years visiting their GP for symptoms suggestive of intermittent claudication or with one risk factor. The ECQ and the ankle brachial index were performed. The prevalence of peripheral arterial disease, defined as an ankle brachial index <0.9, was related to risk factors using logistic regression analyses, on which a clinical decision rule was developed and related to the presence of peripheral arterial disease. RESULTS: Of the 4790 included patients visiting their GP with symptoms suggestive of intermittent claudication, 4527 were eligible for analyses. The prevalence of peripheral arterial disease in this group was 48.3%. The sensitivity of the ECQ was only 56.2%. The prevalence of peripheral arterial disease in a clinical decision rule that included age, male sex, smoking, hypertension, hypercholesterolemia, and a positive ECQ, increased from 14% in the lowest to 76% in the highest category. CONCLUSION: This study indicates that the ECQ alone has an inadequate diagnostic value in detecting patients with peripheral arterial disease. The ankle brachial index should be performed to diagnose peripheral arterial disease in patients with complaints suggestive of intermittent claudication, although our clinical decision rule could help to differentiate between extremely high and lower prevalence of peripheral arterial disease. 相似文献
9.
Alexander Rodewald Rainer Pankau Angela Gosch Armin Wessel 《American journal of medical genetics. Part A》1994,53(3):227-235
The dermatoglyphic patterns of fingertips and palms of 115 patients with Williams-Beuren syndrome (WBS) were analysed and compared with the data from 199 control individuals from Germany. The following combination of dermatoglyphic patterns appears to be characteristic to WBS: an excess of whorls on all fingertips; high termination values of the main lines D, B, and A; frequent absence of C triradius (C°); high frequencies of ulnar loops on the hypothenar and distal loops on the 2nd, 3rd, and 4th inter digital areas, of distal axial triradii t", and of abnormal palmar creases such as simian crease and Sydney lines. The combination of fingertip and palmar patterns expressed by a “Log.Score-Index,” provides a high degree of discrimination between the WBS patients (92%) and the control group (88%). A “phantom picture” for WBS was constructed, which can be used for its diagnosis. © 1994 Wiley-Liss, Inc. 相似文献
10.
Breast cancer detection: one versus two views 总被引:2,自引:0,他引:2
Mammographic examinations of 169 patients with 172 biopsy-proved carcinomas, and of 194 healthy subjects, were interpreted independently and retrospectively by three experienced mammographers, initially as single-view oblique examinations and 6 months later as two-view oblique-cephalocaudal examinations. For the single-view examinations of the cancer patients, 67% of the cancers were correctly recommended for biopsy, additional views were requested for 23%, and a "negative" interpretation was made for 10%. For the single-view examinations of healthy subjects, biopsy was recommended for 7% and additional views were recommended for 32%. For the two-view examinations of women with cancer, 80% of the cancers were correctly recommended for biopsy, additional views were requested for 4%, and a "negative" interpretation was made for 16%. For two-view examinations of healthy subjects, biopsy was recommended for 7% and additional views were requested for only 5%. The authors conclude that single-view screening should not be performed, because it would lead to an excessive number of "call-back" examinations of healthy patients, producing additional cost and anxiety that would outweigh any theoretical benefit. 相似文献