全文获取类型
收费全文 | 6531篇 |
免费 | 393篇 |
国内免费 | 289篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 53篇 |
妇产科学 | 99篇 |
基础医学 | 1260篇 |
口腔科学 | 93篇 |
临床医学 | 454篇 |
内科学 | 992篇 |
皮肤病学 | 75篇 |
神经病学 | 859篇 |
特种医学 | 100篇 |
外科学 | 390篇 |
综合类 | 902篇 |
预防医学 | 310篇 |
眼科学 | 45篇 |
药学 | 535篇 |
中国医学 | 386篇 |
肿瘤学 | 639篇 |
出版年
2024年 | 6篇 |
2023年 | 100篇 |
2022年 | 196篇 |
2021年 | 172篇 |
2020年 | 95篇 |
2019年 | 111篇 |
2018年 | 102篇 |
2017年 | 128篇 |
2016年 | 138篇 |
2015年 | 135篇 |
2014年 | 232篇 |
2013年 | 288篇 |
2012年 | 290篇 |
2011年 | 343篇 |
2010年 | 351篇 |
2009年 | 344篇 |
2008年 | 396篇 |
2007年 | 393篇 |
2006年 | 374篇 |
2005年 | 327篇 |
2004年 | 316篇 |
2003年 | 300篇 |
2002年 | 264篇 |
2001年 | 262篇 |
2000年 | 214篇 |
1999年 | 187篇 |
1998年 | 169篇 |
1997年 | 149篇 |
1996年 | 149篇 |
1995年 | 140篇 |
1994年 | 118篇 |
1993年 | 83篇 |
1992年 | 73篇 |
1991年 | 55篇 |
1990年 | 42篇 |
1989年 | 35篇 |
1988年 | 20篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 26篇 |
1984年 | 17篇 |
1983年 | 3篇 |
1982年 | 8篇 |
1981年 | 11篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有7213条查询结果,搜索用时 31 毫秒
91.
目的:建立一种灵敏度高、特异性强、定量、精确、操作简便的微孔板酶联夹心杂交技术,定量检测人IL-8 mR-NA。方法:针对人IL-8 mRNA逆转录聚合酶链反应产物一条链的不同区域序列设计一对特异探针,其中一条为捕获探针,5′端用活性氨基修饰,与微量DNA结合板表面的NOS基团共价结合,“竖直”地包被在微孔板内;另一条检测探针的3′端标记生物素,和辣根过氧化物酶结合。提取人外周血单个核细胞总RNA,进行RT-PCR扩增IL-8 mRNA,双链DNA产物经热变性后加入已包被捕获探针的微孔板内进行杂交,加入检测探针与已杂交的产物结合,经亲和素-辣根过氧化物酶系统检测杂交信号。结果:该法灵敏度为检出16个循环的PCR产物、5×103个PBMCs中的IL-8 mRNA、检测PCR终产物的最高稀释倍数为1∶256阳性;特异性试验非目的扩增片段酶联杂交检测未检出阳性杂交信号;精密度试验CV为5.2%。结论:该方法具有操作简便、灵敏度高、特异性强等优点,适合IL-8 mRNA PCR扩增产物的定量检测。 相似文献
92.
In situ localization of mRNA for the fibrinolytic factors uPA, PAI-1 and uPAR in endometriotic and endometrial tissue 总被引:4,自引:0,他引:4
Endometriotic tissue grows invasively. The plasminogen-activating system is suggested to participate in degradation of extracellular matrix (ECM) and modulation of cell adhesion and migration. We have previously demonstrated elevated levels of the fibrinolytic factors urokinase plasminogen activator (uPA) and plasminogen activator inhibitor (PAI-1) in endometriotic tissue and endometrium from women with endometriosis. The aim of the present study was to localize the uPA, PAI-1 and urokinase plasminogen activator receptor (uPAR) mRNA in endometriotic tissue and in endometrium both from women with and without endometriosis. With in situ hybridization, we found that uPA mRNA seems to be up-regulated in endometriotic glands and endometrial stroma as well as PAI-1 mRNA in endometriotic and endometrial stroma from women with endometriosis. uPAR mRNA likewise appears to be up-regulated in both glands and stroma in endometriotic tissue and in endometrial glands from patients compared to endometrial glands and stroma from healthy women. These differences might be important for menstrual shedding and adherence of endometrial fragments to peritoneal lining in women developing endometriosis and for the invasive growth of endometriotic tissue. 相似文献
93.
JOSTARNDT-F
GEN PUNTSCHART HOPPELER BILLETER 《Acta physiologica (Oxford, England)》1998,164(3):299-308
The fibre-type specific expression patterns of fast and slow isoforms of essential (alkali) myosin light chains (ELC) was analysed in trained, untrained and pathological human muscles. Biopsies from m. vastus lateralis of moderately trained and untrained persons, as well as highly trained endurance and strength athletes were analysed, by in situ hybridization, for the expression of the `fast' ELC 1f/3f and the `slow' ELC 1sb. We wanted to investigate if changes in the fibre-type specific ELC mRNA pattern could be used as markers for training adaptation, especially, if the mRNA of the slow ELC 1sb isoform would appear in type IIA fibres as a result of endurance training (Baumann et al. 1987). We found the fast/slow ELC expression patterns in the fibre types to be remarkably stable. Physiological stress, even high training loads, did not affect it. No IIA fibres expressing ELC 1sb mRNA were found. They could be detected, however, in pathological muscle samples, where fast/slow ELC patterns not found in normal muscles were frequent. Our data suggest that in healthy muscles, only a subset of the theoretically possible combinations of myosin heavy and light chain isoforms are expressed at the level of their mRNAs. 相似文献
94.
95.
96.
Indications of immunological tolerance in kidney transplantation 总被引:5,自引:0,他引:5
97.
Polymorphic variants in the gene encoding factor VII (F7) affect the plasma levels of this coagulation protein and modify the clinical phenotype of FVII deficiency in some patients. In this study we report the in vitro functional analysis of a novel polymorphic variant located in the 3' untranslated region of F7: g.11293_11294insAA. To determine whether this variant regulates FVII expression, we initially compared an expression vector containing FVII cDNA with g.11293_11294insAA with the FVII wild-type (WT) construct. The kinetics of mRNA production showed that the insertion decreases the steady-state FVII mRNA levels. To assess whether the insertion influences the phenotype of FVII-deficient patients, we evaluated its effect on the expression of FVII in a patient with severe FVII deficiency (undetectable FVII activity and antigen) carrying two additional homozygous missense variations (p.Arg277Cys and p.Arg353Gln). The two substitutions alone reduced the expression of FVII activity and antigen in vitro, but with the insertion polymorphism in our expression vector the patient's phenotype of undetectable plasma FVII was recapitulated. The insertion polymorphism in the 3' untranslated region of F7 is another modifier of FVII expression that might explain the poor genotype-phenotype correlation in some FVII-deficient patients. 相似文献
98.
A. Seto-Ohshima P. C. Emson M. W. Berchtold C. W. Heizmann 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1989,75(3):653-658
Summary Parvalbumin mRNA was localized in rat brain by in situ hybridization using a 35S labelled rat parvalbumin cDNA and a synthetic oligodeoxyribonucleotide (corresponding to base sequences 140 to 183 of rat parvalbumin cDNA). Strongest hybridization signals were detected in the Purkinje cells of the cerebellum and in neurones of the reticular nucleus of the thalamus. Signal was also detected in the cerebral cortex, hippocampus, basal ganglia and brain stem in agreement with the distribution of parvalbumin immunoreactivity. 相似文献
99.
100.
Yasuhiro Yoshikawa Hiroshi Tsuruoka Mineo Matsumoto Takeshi Haga Tatsuo Shioda Hiroshi Shibuta Takeshi A. Sato Kazuya Yamanouchi 《Virus genes》1990,4(2):151-161
The nucleotide sequence of a cloned cDNA corresponding to the P+M dicistronic mRNA of a subacute sclerosing panencephalitis (SSPE) virus was determined and compared with data of measles virus (MV). The dicistronic mRNA of the SSPE virus consisted of the 3 proximal 626 nucleotides of P mRNA, intercistronic trinucleotides, a full length of M mRNA, and 75 poly A nucleotides. The part encoding the P protein had a high homology to MV, except at the noncoding region. The terminating consensus sequence of the P gene and the intercistronic trinucleotides of the SSPE virus were CTAC(A)6 and CCT; in MV they are TTAT(A)6 and CTT, respectively. In the M gene, the starting consensus sequence was exactly the same as MV, but at the 5 proximal end, one third of this gene was different: The first ATG codon of the MV M gene signaling opening of the reading frame was changed to ACG in the SSPE virus and one long open reading frame started from the third ATG codon. The stop codon (TAG) of the MV M gene was also changed to CAG in the SSPE virus. Thus, the deduced SSPE-virus M protein lacked 50 amino acids at the amino terminal and had 15 extra amino acids at the carboxyl end when compared with the MV M protein. 相似文献