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141.
【背景】内生固氮菌可以定殖于植物体内为植物提供营养物质,还能通过代谢促进植物生长,目前对于落地生根内生菌的研究鲜见报道。【目的】研究落地生根中内生固氮菌多样性。【方法】从表面消毒的植物组织中分离纯化内生菌,并通过乙炔还原法测定菌株的固氮酶活性。采用SDS-PAGE全细胞蛋白电泳和IS指纹图谱对菌株聚类,各类群代表菌株进行16S rRNA基因系统发育分析和生理生化鉴定。测定菌株固氮、分泌生长素和ACC脱氨酶、产铁载体、溶磷和解钾等促生特性。【结果】从落地生根中分离纯化出26株内生固氮菌,聚为5个类群,隶属于4个属的5个菌种,且各类群代表菌株具有多种促生功能。【结论】从落地生根中分离获得的内生菌具有丰富的遗传多样性和促生特性,并且存在新的微生物资源,有待开发利用。 相似文献
142.
本文用5种动物的370例心脏,对右心室条束作了比较解剖学观察。狗右心室条束的出现率为97%,兔64%,牛52%,猪38%,羊25%。牛、猪、羊和兔的右心室条事多附着室间隔和室前壁之间,狗的条束多附着前乳头肌或室间隔和前壁之间。动物的右心室要束可分暗红色条束和乳白色条束,暗红色条束主要由心肌纤维构成,条不周边的结缔组织中含有不细胞;乳白色条束主要由结缔组织和位于中央的呸细胞构成,心肌纤维少或缺如。心 相似文献
143.
水淹对钉螺卵影响的透射电镜观察 总被引:2,自引:0,他引:2
春汛期钉螺繁殖期在洞庭湖现场进行水淹螺卵试验,观察螺卵结构的动态变化。结果显示,对照组螺卵胶膜由胶原纤维层和基底膜组成,卵细胞核大,呈圆形或椭圆形,染色质丰富,细胞内含丰富线粒体、内质网和分泌颗粒等。水淹10d时,结构尚未见明显变化;至20d时,胶膜胶原纤维横纹不清,断裂有空洞,线粒体肿胀,嵴结构不清,核内染色质减少;30d时,出现核固缩或崩解,线粒体消失。说明在螺卵发育期水淹能很快使其发生病理损 相似文献
144.
145.
Lipoprotein lipase activity is decreased in a large cohort of patients with coronary artery disease and is associated with changes in lipids and lipoproteins 总被引:19,自引:0,他引:19
Henderson HE Kastelein JJ Zwinderman AH Gagné E Jukema JW Reymer PW Groenemeyer BE Lie KI Bruschke AV Hayden MR Jansen H 《Journal of lipid research》1999,40(4):735-743
Lipoprotein lipase (LPL) is crucial in the hydrolysis of triglycerides (TG) in TG-rich lipoproteins in the formation of HDL particles. As both these lipoproteins play an important role in the pathogenesis of atherosclerotic vascular disease, we sought to assess the relationship between post-heparin LPL (PH-LPL) activity and lipids and lipoproteins in a large, well-defined cohort of Dutch males with coronary artery disease (CAD). These subjects were drawn from the REGRESS study, totaled 730 in number and were evaluated against 75 healthy, normolipidemic male controls. Fasting mean PH-LPL activity in the CAD subjects was 108 46 mU/ml, compared to 138 44 mU/ml in controls (P < 0.0001). When these patients were divided into activity quartiles, those in the lowest versus the highest quartile had higher levels of TG (P < 0.001), VLDLc and VLDL-TG (P = 0.001). Conversely, levels of TC, LDL, and HDLc were lower in these patients (P = 0.001, P = 0.02, and P = 0.001, respectively). Also, in this cohort PH-LPL relationships with lipids and lipoproteins were not altered by apoE genotypes. The frequency of common mutations in the LPL gene associated with partial LPL deficiency (N291S and D9N carriers) in the lowest quartile for LPL activity was more than double the frequency in the highest quartile (12.0% vs. 5.0%; P = 0.006). By contrast, the frequency of the S447X LPL variant rose from 11.5% in the lowest to 18.3% (P = 0.006) in the highest quartile. This study, in a large cohort of CAD patients, has shown that PH-LPL activity is decreased (22%; P = 0.001) when compared to controls; that the D9N and N291S, and S447X LPL variants are genetic determinants, respectively, in CAD patients of low and high LPL PH-LPL activities; and that PH-LPL activity is strongly associated with changes in lipids and lipoproteins. 相似文献
146.
147.
The predisposition to type 1 diabetes linked to the human leukocyte antigen complex includes at least one non-class II gene 总被引:8,自引:0,他引:8 下载免费PDF全文
Lie BA Todd JA Pociot F Nerup J Akselsen HE Joner G Dahl-Jørgensen K Rønningen KS Thorsby E Undlien DE 《American journal of human genetics》1999,64(3):793-800
The human leukocyte antigen (HLA) complex, encompassing 3.5 Mb of DNA from the centromeric HLA-DPB2 locus to the telomeric HLA-F locus on chromosome 6p21, encodes a major part of the genetic predisposition to develop type 1 diabetes, designated "IDDM1." A primary role for allelic variation of the class II HLA-DRB1, HLA-DQA1, and HLA-DQB1 loci has been established. However, studies of animals and humans have indicated that other, unmapped, major histocompatibility complex (MHC)-linked genes are participating in IDDM1. The strong linkage disequilibrium between genes in this complex makes mapping a difficult task. In the present paper, we report on the approach we have devised to circumvent the confounding effects of disequilibrium between class II alleles and alleles at other MHC loci. We have scanned 12 Mb of the MHC and flanking chromosome regions with microsatellite polymorphisms and analyzed the transmission of these marker alleles to diabetic probands from parents who were homozygous for the alleles of the HLA-DRB1, HLA-DQA1, and HLA-DQB1 genes. Our analysis, using three independent family sets, suggests the presence of an additional type I diabetes gene (or genes). This approach is useful for the analysis of other loci linked to common diseases, to verify if a candidate polymorphism can explain all of the association of a region or if the association is due to two or more loci in linkage disequilibrium with each other. 相似文献
148.
We constructed a mouse PC6B truncated mutant and introduced a tag of 6 consecutive histidines at its carboxyl terminus for simple purification. Using the baculovirus expression system and standard enzymatic assay, we obtained recombinant mouse PC6B protein and with enzymatic activity. 相似文献
149.
Sheng Y Li L Wang C Li Y Guo D 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,806(2):127-132
A sensitive and rapid high-performance liquid chromatography (HPLC) method with solid-phase extraction (SPE) to simultaneously determine albiflorin and paeoniflorin in rat serum was described. Serum samples were pretreated with solid-phase extraction using Extract-Clean cartridges, and the extracts were analyzed by HPLC on a reversed-phase C(18) column and a mobile phase of acetonitrile-0.03% formic acid (17:83 (v/v)) with ultraviolet detection at 230 nm. Pentoxifylline was used as the internal standard (IS). The linear ranges of the calibration curves were 29-1450 ng/ml for albiflorin and 10-2000 ng/ml for paeoniflorin. The intra- and inter-day precisions (R.S.D.) were 相似文献
150.
In the proprotein convertases family, mouse PC6B (mPC6B) has a very large cysteine-rich region (CRR), consisting of 22 tandem
cysteine-rich (Cys-rich) repeated segments. The role of this region remains elusive. In this report, to get insight on the
possible role of the CRR, we constructed four truncated mPC6B mutant genes with 0, 5, 11, and 22 Cys-rich repeated segments
remaining; using the baculovirus-expression system and a simple purification method, we obtained four enzyme mutants of mPC6B.
By determining their optimal pH and calcium ion concentration for enzymatic activity and their thermal stability, we found
that CRR did not affect pH optimum and Ca2+ optimum compared with the p-domain. However, CRR acted as a stabilizing domain in addition to the p-domain. By kinetic analyses
of four mutants, we found that the long Cys-rich repeats in the native form of mPC6B reduced its V
max. These facts suggest that CRR acts as an important part of functional domain. 相似文献