全文获取类型
收费全文 | 1388篇 |
免费 | 74篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 34篇 |
儿科学 | 34篇 |
妇产科学 | 18篇 |
基础医学 | 105篇 |
口腔科学 | 20篇 |
临床医学 | 131篇 |
内科学 | 252篇 |
皮肤病学 | 13篇 |
神经病学 | 65篇 |
特种医学 | 83篇 |
外科学 | 375篇 |
综合类 | 28篇 |
一般理论 | 9篇 |
预防医学 | 58篇 |
眼科学 | 10篇 |
药学 | 117篇 |
肿瘤学 | 128篇 |
出版年
2023年 | 15篇 |
2022年 | 20篇 |
2021年 | 30篇 |
2020年 | 26篇 |
2019年 | 38篇 |
2018年 | 56篇 |
2017年 | 31篇 |
2016年 | 31篇 |
2015年 | 35篇 |
2014年 | 49篇 |
2013年 | 64篇 |
2012年 | 91篇 |
2011年 | 112篇 |
2010年 | 63篇 |
2009年 | 67篇 |
2008年 | 71篇 |
2007年 | 69篇 |
2006年 | 79篇 |
2005年 | 63篇 |
2004年 | 56篇 |
2003年 | 42篇 |
2002年 | 53篇 |
2001年 | 32篇 |
2000年 | 14篇 |
1999年 | 17篇 |
1998年 | 30篇 |
1997年 | 13篇 |
1996年 | 14篇 |
1995年 | 12篇 |
1994年 | 17篇 |
1993年 | 6篇 |
1992年 | 13篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 12篇 |
1988年 | 14篇 |
1987年 | 14篇 |
1986年 | 14篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1974年 | 7篇 |
1973年 | 3篇 |
排序方式: 共有1480条查询结果,搜索用时 0 毫秒
1.
2.
3.
Circulating prostate specific antigen-positive cells correlate with metastatic prostate cancer. 总被引:11,自引:0,他引:11
F C Hamdy J Lawry J B Anderson M A Parsons R C Rees J L Williams 《British journal of urology》1992,69(4):392-396
Analytical flow cytometry was used to study circulating prostate specific antigen (PSA)-positive cells in 40 consecutive patients with newly diagnosed, untreated prostate cancer; 25 patients (63%) had metastatic disease confirmed by a positive bone scan. Cell suspensions were prepared for each patient from both the primary tumour and peripheral blood samples. The cells were stained with a monoclonal antibody against PSA, and analysed by flow cytometry; PSA-positive cells were sorted according to their immunofluorescence and light scatter properties. The cellular deoxyribonucleic acid (DNA) content of each specimen was also analysed to establish ploidy status. PSA-positive cells were detected in the peripheral blood of 33 patients (83%). The presence of these cells in the circulation showed a higher degree of sensitivity and specificity in predicting positive bone scans than did serum PSA levels. Circulating PSA-positive cells may represent either a subpopulation of tumour cells with distinct metastatic properties or, alternatively, host immunocytes which take up PSA in an active or passive manner. 相似文献
4.
5.
6.
Role for Fimbriae and Lysine-Specific Cysteine Proteinase Gingipain K in Expression of Interleukin-8 and Monocyte Chemoattractant Protein in Porphyromonas gingivalis-Infected Endothelial Cells 总被引:3,自引:0,他引:3 下载免费PDF全文
7.
Anderson RA; Wallace AM; Kicman AT; Wu FC 《Human reproduction (Oxford, England)》1997,12(8):1657-1662
Administration of supraphysiological doses of testosterone to normal men
causes inhibition of spermatogenesis, but while most become azoospermic,
30-55% maintain a low rate of spermatogenesis. We have investigated whether
there are differences in endogenous androgen production, of testicular and
adrenal origin, which may be related to the degree of suppression of
spermatogenesis. Thirty-three healthy Caucasian men were given weekly i.m.
injections of 200 mg testosterone oenanthate (TE), 18 became azoospermic,
while 15 remained oligozoospermic. Urinary excretion of epitestosterone, a
specific testicular product, was reduced to <10% of pretreatment values,
with no differences between the groups. Similar results were obtained for
other markers of testicular steroidogenesis. Urinary and plasma adrenal
androgens were also reduced during TE treatment: a statistically
significant decrease in both (P < 0.001 and P < 0.05 respectively)
was seen in the azoospermic but not oligozoospermic responders. These
results suggest that testicular steroidogenesis is decreased to <10% by
the administration of supraphysiological doses of exogenous testosterone.
Differences in the degree of ongoing steroidogenesis in the testis do not
appear to account for incomplete suppression of spermatogenesis, thus
differences in androgen metabolism may underlie this heterogeneous
response. A small but significant reduction in secretion of adrenal
androgens was also detectable, the relevance of which is unclear.
相似文献
8.
Bedaiwy MA Goldberg JM Falcone T Singh M Nelson D Azab H Wang X Sharma R 《Human reproduction (Oxford, England)》2002,17(3):601-604
BACKGROUND: Oxidative stress mechanisms are involved in the pathophysiology of many reproductive disorders. The objective of this study was to characterize oxidative stress parameters in hydrosalpingeal fluid (HSF) and examine their possible role in early embryo development. METHODS AND RESULTS: HSF was aspirated at laparoscopic salpingectomy in 11 infertile women. Reactive oxygen species (ROS), total (non-enzymatic) antioxidant capacity (TAC) and lipid peroxidation (LPO) were assayed. Two-cell mouse embryos were incubated with 25, 50 or 75% HSF and the blastocyst development rate was observed. ROS was detected in five of 11 (45%) HSF samples with a mean of 4.2 x 10(4) c.p.m. LPO was detected in all samples at a mean (+/- SD) value of 5575.4 +/- 6091.9 micromol/l malonaldehyde. The mean blastocyst development rate at 25, 5+/- 0 and 75% HSF and in the control group was 88.9 +/- 9.4, 65.7 +/- 19.1, 45.7 +/- 5.7 and 96.7% respectively (P < 0.0001). The blastocyst development rate was positively correlated to ROS concentrations (P < 0.02) but was not significantly related to LPO. CONCLUSIONS: The blastocyst development rate decreased with increasing concentrations of HSF. For the first time, the presence of ROS, LPO and TAC activity in human HSF was characterized. A possible role of oxidative stress in the embryotoxicity of HSF is suggested. 相似文献
9.
Most nutrition studies looking at the association of food with cardiometabolic markers rely on food frequency questionnaires, which are prone to recall bias. Pentadecanoic acid, heptadecanoic acid and trans-palmitoleic acid are fatty acids that are not synthesized endogenously but are obtained from the diet, particularly dairy, making them reasonable biomarkers of dairy consumption. We investigated the association of dairy fatty acid biomarkers with glycated hemoglobin (HbA1c) and cardiovascular risk factors in type 2 diabetes (T2D). In a clinical trial, 111 participants with T2D (age 58.5 ± 8.9 years, HbA1c 8.09 ± 0.96%) were randomized into three groups: a control group that maintained baseline dairy intake, a low-fat (LF) group that incorporated ≥3 servings/day of LF dairy and a high-fat (HF) group that incorporated ≥3 servings/day of HF dairy. We compared the fatty acids (FA) composition between the three groups at 24 weeks. Pentadecanoic acid and trans-palmitoleic acid increased in the HF group by 14.1% ± 5.4% and 17.5% ± 5.1%, respectively, but not in the control and LF groups (p = 0.0474 and p = 0.0025 for group-by-time interaction, respectively). Those increases were positively associated with changes in total cholesterol, very-low-density lipoprotein cholesterol VLDL-C and triglycerides but were not associated with changes in HbA1c from baseline to 24 weeks. These results suggest that the intervention was successful and that participants were likely compliant, which supports the validity of the main trial. 相似文献
10.