全文获取类型
收费全文 | 14351篇 |
免费 | 39篇 |
国内免费 | 71篇 |
专业分类
教育 | 9097篇 |
科学研究 | 1065篇 |
各国文化 | 439篇 |
体育 | 2372篇 |
综合类 | 257篇 |
文化理论 | 98篇 |
信息传播 | 1133篇 |
出版年
2023年 | 114篇 |
2022年 | 142篇 |
2021年 | 69篇 |
2020年 | 71篇 |
2019年 | 72篇 |
2018年 | 58篇 |
2016年 | 90篇 |
2015年 | 225篇 |
2014年 | 568篇 |
2013年 | 656篇 |
2012年 | 672篇 |
2011年 | 1138篇 |
2010年 | 720篇 |
2009年 | 507篇 |
2008年 | 698篇 |
2007年 | 593篇 |
2006年 | 772篇 |
2005年 | 705篇 |
2004年 | 630篇 |
2003年 | 651篇 |
2002年 | 461篇 |
2001年 | 232篇 |
2000年 | 189篇 |
1999年 | 171篇 |
1998年 | 91篇 |
1997年 | 137篇 |
1996年 | 113篇 |
1995年 | 130篇 |
1994年 | 140篇 |
1993年 | 137篇 |
1992年 | 165篇 |
1991年 | 153篇 |
1990年 | 192篇 |
1989年 | 190篇 |
1988年 | 225篇 |
1987年 | 304篇 |
1986年 | 283篇 |
1985年 | 347篇 |
1984年 | 259篇 |
1983年 | 242篇 |
1982年 | 217篇 |
1981年 | 181篇 |
1980年 | 102篇 |
1979年 | 44篇 |
1959年 | 40篇 |
1957年 | 51篇 |
1956年 | 68篇 |
1955年 | 64篇 |
1954年 | 66篇 |
1953年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
992.
今天我与大家交流美国国家档案馆(NARA)在保存历史和开放档案中面临的挑战以及我们正在通过怎样的方式将美国公众与他们的档案建立起联系。一、政务公开对档案工作的影响奥巴马总统在就职第一天就发表了关于政务公开倡议的演讲,他在最近发表的 相似文献
994.
Farrokhi E Shayesteh F Asadi Mobarakeh S Roghani Dehkordi F Ghatreh Samani K Hashemzadeh Chaleshtori M 《Indian journal of clinical biochemistry : IJCB》2011,26(3):244-248
Familial hypercholesterolemia (FH) is an autosomal dominant disorder of lipoprotein metabolism caused mainly by mutations
in the low-density lipoprotein receptor (LDLR) and apolipoprotein B 100 (APOB) genes. Until now, the molecular basis of FH
has been demonstrated in detail in many populations, but there is still very limited Molecular data concerning FH in Iran.
The aim of this study was to characterize the LDLR and APOB gene mutations in an Iranian population. A total of 30 non-related
Iranian possible FH subjects were studied. Diagnosis of FH was based on the Dutch Lipid Clinic Network diagnostic criteria.
All samples were initially tested for three common APOB gene mutations including R3500Q, R3500 W and R3531C using PCR-RFLP
assay. Subsequently, promoter and coding region of the LDLR gene was screened by PCR-SSCP analysis and positive results were
confirmed by DNA sequencing. Four previously reported polymorphisms 1413G > A, 1725C > T, 1773T > C and 2140 + 5G > A were
found in ~17% (5/30) of population studied. Moreover, no variation was found in APOB gene. Our data indicated that LDLR and
APOB gene mutations have not contribution to possible FH in Iranian population studied here. However, we examined three common
APOB mutations and LDLR in only 30 patients, and to determine the role of these genes in developing FH in Iran, more FH samples
and populations needed to be investigated for the mutations of the related genes. 相似文献
995.
Dash P Pati S Mangaraj M Sahu PK Mohapatra PC 《Indian journal of clinical biochemistry : IJCB》2011,26(2):182-186
Now a days measurement of molecular forms of PSA has gained importance in clinical practice. Several studies have demonstrated
the production of PSA in female tissues, such as breast. The present piece of work has been undertaken with an objective to
estimate the relative proportion of the molecular forms of PSA in serum along with serum testosterone in benign and malignant
breast tumor cases and to analyze their association with the severity of the disease process 34 malignant and 26 benign breast
disease cases along with 33 healthy controls of same age group were enrolled in this study for evaluation. Serum testosterone
was measured by ELISA, whereas serum total PSA (TPSA) and free PSA (FPSA) were estimated by electrochemiluminescence immunoassay.
A significant rise of fasting plasma glucose along with prominent dyslipidemia was observed in breast tumor cases. Marked
rise in serum testosterone as well as TPSA and FPSA was documented in both benign and malignant breast tumor cases. Serum
testosterone revealed a significant positive association with both TPSA and FPSA pointing towards an etiological association
between them. However, surgical removal of tumor mass resulted in a marked decline of presurgical value of both TPSA and FPSA
with a non-significant fall in serum testosterone revealing tumor tissue as the source of FPSA and TPSA. Thus, estimation
of PSA provides prognostic information that may assist in future treatment. 相似文献
996.
997.
Gupta S Verma M Gupta AK Kaur A Kaur V Singh K 《Indian journal of clinical biochemistry : IJCB》2011,26(2):178-181
Thyroid function tests are very important for the diagnosis and monitoring of patients with thyroid dysfunction. The guidelines
recommend serum thyroid stimulating hormone (TSH) as the single most reliable test to diagnose all common forms of hypothyroidism
and hyperthyroidism. The aim of this study was to analyze the ordering pattern for thyroid function tests by physicians and
the analysis of results based on the clinical history. The mean age of the patients was 32.5 ± 6.5 years. Majority of samples
(87.7% of total) were received from the departments of Medicine and Gynae. Thyroid profiles (47.5%) were ordered more frequently
as compared to TSH only (46%). There was no significant difference in the percentage of normal reports for both types of tests.
77.8% of TFT and 76.6% of TSH samples had results within the reference range. The percentage of abnormal results was 13.7%
in the patients who were screened for thyroid disorders. There is a need to redefine the case definition for thyroid dysfunction
and order the appropriate test in a rational and cost effective manner. 相似文献
998.
999.
1000.
我小时候,家住在村头。我很喜欢睡在房顶上,在这里什么都可以听得见,还可以看得很远。村子左边是一片光秃秃的荒沙地;右边和后面都是果园;正面是一条很深的山沟,山沟里奔流着—道溪水。
一天,天还不亮流水声就把我唤醒了。我望着外面,忽然发现山沟那边有什么东西闪了一下。 相似文献