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991.
《International journal for parasitology》2022,52(6):343-358
Schistosome invasive stages, cercariae, leave intermediate snail hosts, penetrate the skin of definitive hosts, and transform to schistosomula which migrate to the final location. During invasion, cercariae employ histolytic and other bioactive products of specialized holocrine secretory cells – postacetabular (PA) and circumacetabular (CA) penetration glands. Although several studies attempted to characterize protein composition of the in vitro-induced gland secretions in Schistosoma mansoni and Schistosoma japonicum, the results were somewhat inconsistent and dependent on the method of sample collection and processing. Products of both gland types mixed during their secretion did not allow localization of identified proteins to a particular gland. Here we compared proteomes of separately isolated cercarial gland cells of the avian schistosome Trichobilharzia szidati, employing laser-assisted microdissection and shotgun LC-MS/MS, thus obtaining the largest dataset so far of the representation and localization of cercarial penetration gland proteins. We optimized the methods of sample processing with cercarial bodies (heads) first. Alizarin-pre-stained, chemically non-fixed samples provided optimal results of MS analyses, and enabled us to distinguish PA and CA glands for microdissection. Using 7.5 × 106 μm3 sample volume per gland replicate, we identified 3347 peptides assigned to 792 proteins, from which 461 occurred in at least two of three replicates in either gland type (PA = 455, 40 exclusive; CA = 421, six exclusive; 60 proteins differed significantly in their abundance between the glands). Peptidases of five catalytic types accounted for ca. 8% and 6% of reliably identified proteins in PA and CA glands, respectively. Invadolysin, nardilysin, cathepsins B2 and L3, and elastase 2b orthologs were the major gland endopeptidases. Two cystatins and a serpin were highly abundant peptidase inhibitors in the glands. While PA glands generally had rich enzymatic equipment, CA glands were conspicuously abundant in venom allergen-like proteins. 相似文献
992.
Krijn B. Michel Egon Heiss Peter Aerts Sam Van Wassenbergh 《Proceedings. Biological sciences / The Royal Society》2015,282(1805)
To capture and swallow food on land, a sticky tongue supported by the hyoid and gill arch skeleton has evolved in land vertebrates from aquatic ancestors that used mouth-cavity-expanding actions of the hyoid to suck food into the mouth. However, the evolutionary pathway bridging this drastic shift in feeding mechanism and associated hyoid motions remains unknown. Modern fish that feed on land may help to unravel the physical constraints and biomechanical solutions that led to terrestrialization of fish-feeding systems. Here, we show that the mudskipper emerges onto land with its mouth cavity filled with water, which it uses as a protruding and retracting ‘hydrodynamic tongue’ during the initial capture and subsequent intra-oral transport of food. Our analyses link this hydrodynamic action of the intra-oral water to a sequence of compressive and expansive cranial motions that diverge from the general pattern known for suction feeding in fishes. However, the hyoid motion pattern showed a remarkable resemblance to newts during tongue prehension. Consequently, although alternative scenarios cannot be excluded, hydrodynamic tongue usage may be a transitional step onto which the evolution of adhesive mucosa and intrinsic lingual muscles can be added to gain further independence from water for terrestrial foraging. 相似文献
993.
摘要 目的:探究改良眼底激光光凝联合康柏西普治疗增殖性糖尿病视网膜病变(PDR)的效果及对视力水平、黄斑区血流密度的影响。方法:回顾性分析2019.06-2022.06于我院接受改良眼底激光光凝治疗的62例(124眼)PDR患者临床资料,纳入对照组,回顾性分析同期于我院接受改良眼底激光光凝联合康柏西普治疗的62例(124眼)PDR患者临床资料,纳入试验组。比较治疗前和治疗后3个月两组患者视力水平[最佳矫正视力(BCVA)、视野指数(VFI)、视野平均缺损(MD)]、视网膜中央动脉血流动力学[峰值血流速度(PSV)、平均血流速度(MV)、搏动指数(PI)、阻力指数(RI)]、黄斑区血流密度[浅层毛细血管丛(SCP)、深层毛细血管丛(DCP)]、生活质量[低视力者生存质量量表(CLVQOL)]差异,记录3个月内两组患者并发症(黄斑水肿、高眼压、视网膜出血)发生情况。结果:治疗后3个月,两组患者BCVA、PSV、MV、SCP、DCP、CLVQOL较治疗前升高,试验组高于对照组(P均<0.05);而VFI、MD、PI、RI水平降低,试验组低于对照组(P均<0.05);两组患者术后并发症无显著性差异(P>0.05)。结论:改良眼底激光光凝治疗联合康柏西普治疗可增强PDR患者视力功能,改善患者视网膜中央动脉血流动力学及黄斑区血流密度,提高生活质量。 相似文献
994.
Daniel Mdetele Gerald Misinzo Erick Komba Justin Shemanche Ernest Eblate Maulid Mdaki Julius Keyyu Richard Kock 《African Journal of Ecology》2021,59(1):152-158
During serological surveillance of peste des petits ruminants (PPR) disease, it required capture of randomly selected herds of gazelles as part of a study to determine the epidemiological role of these species in the circulation of peste des petits ruminants virus (PPRV). The study targeted capturing 135 Grant's gazelles (Gazella granti) from the Serengeti ecosystem, Tanzania. A modified netting technique was used aiming at providing safe, efficient and cost‐effective method for capture of gazelles. Locally available materials were used, and wildlife professionals guided the process of manufacturing supporting frame for the nets. Twenty (20) black metal pipes, 20 metal bars, four nets and three vehicles were used in the procedure. A total of 136 Grant's gazelles and nine Thomson's gazelles were captured in three missions. The Grant's gazelles were captured as per sample size calculated in all locations: Loliondo (n = 25), Serengeti National Park (n = 44) and Ngorongoro Conservation Area (NCA) (n = 67) using less time and minimum cost than estimated. Injuries of three fawns (2%) inadvertently captured with the groups of adults and sub‐adult animals were recorded. Comparing with 2014 and other studies, modified netting technique showed high animal and operator safety levels with minimal injuries. With this technique, it was possible to capture even flighty animals that behave nervously because of hunting and other human activities, including Thomson's gazelles, a species previously found to be difficult to capture by netting. 相似文献
995.
近视眼激光角膜切除术原理及控制方法 总被引:14,自引:2,他引:14
本文从理论上研究了激光人眼角膜切除术的原理和控制方法。详细分析了角膜前表面的曲率半径对近发消融深度和治疗结果的影响。 相似文献
996.
传统的DNA重组方法Type Ⅱ型限制酶技术受到片段纯化的限制,无法做到复杂混合体系中DNA片段的特异性连接。为解决这个问题,本研究将耐热连接酶链式反应(Thermostable ligase chain reaction, TLCR)引入DNA片段的连接与捕获。该技术利用耐热型DNA连接酶的特性,在热循环反应中配合针对目的片段末端序列设计的单链寡核苷酸连接模板--Helper,实现目的片段的特异性连接和产物数量的指数性增长。两个质粒构建实验被用于验证TLCR技术的可行性和应用效果。首先利用TLCR技术从一个未经纯化的含有7种不同大小片段的混杂体系中特异性地将一段1.5 kb的片段捕获进载体,随机抽取的克隆样品经检验准确率达到80%,验证TLCR技术在复杂混合体系中特异性连接DNA片段的可行性和准确性。在另一个质粒构建实验中,TLCR技术从λ噬菌体基因组Hind消化物中将两段总长达27 kb的片段按顺序捕获进载体,随机抽取的克隆样品经检验同样达到了80%的准确率。结果表明,TLCR技术能够简化DNA重组实验的操作,并且适用于多片段和大片段的连接,可以为生物学研究提供便利。 相似文献
997.
光动力疗法 (PDT) 已发展成为一种较成熟的肿瘤治疗方法, PDT 诱导的血管损伤是杀死肿瘤的重要机制之一 . 为了在活体肿瘤模型上实时监测 PDT 导致的血管损伤效应,使用稳定高表达绿色荧光蛋白 (GFP) 的人涎腺腺样囊性癌细胞株 (ACC-M-GFP) ,建立了基于鸡胚尿囊膜 (CAM) 的肿瘤模型 . 应用荧光成像技术对肿瘤的生长位置、大小,以及治疗区域进行方便精确的定位;利用激光散斑成像技术,实时监测 CAM 上肿瘤周围血管的血液动力学参数 . 发现不同光动力剂量所导致的血管损伤有显著不同 . 结果表明,荧光标记的鸡胚尿囊膜肿瘤模型为研究 PDT 导致的血管损伤效应提供了良好的实验模型,激光散斑成像技术适用于实时监测 PDT 过程中血管结构、血流速度的变化,由此得出血液灌注率可用以评估 PDT 对肿瘤周围血管的损伤效应 . 相似文献
998.
C. J. Topping 《Entomologia Experimentalis et Applicata》1993,68(3):287-293
The behaviour of three linyphiid spider species (Araneae: Linyhiidae) towards pitfall traps was investigated in an experimental arena. Capture efficiencies were low with a mean of between 16 and 57 traps being encountered before spiders were caught. Survival time, trap encounter rate, trap entry rate and reactions towards vegetation were all found to be species-specific. These behaviours are considered to affect differentially pitfall trap efficiency and may partially explain the lack of clear relationship between pitfall trap catch and density found in published studies. 相似文献
999.
本研究拟建立肌酸激酶同工酶MB(CK-MB)特异性单克隆抗体(m Ab)的研制方法,对抗CK-MB单抗进行评价分类及性质鉴定,并初步建立CK-MB定量检测试剂。以CK-MB抗原免疫BALB/c小鼠,利用常规单抗制备技术,使用间接和捕获ELISA差异筛选法筛选单抗。利用肌酸激酶同工酶(CK-MM/BB/MB)抗原对所制备单抗的抗原识别表位进行鉴定,另通过免疫印迹法及合成CK-MM、CK-BB差异性的线性表位肽鉴定对所制备的单抗进行评价分类。使用双抗体夹心ELISA方法筛选检测CK-MB抗原的配对m Ab,并初步建立CK-MB定量检测试剂。使用74例临床标本初步评价该试剂与罗氏试剂的检测一致性。最终,我们成功筛选到22株稳定分泌抗CK-MB抗体的杂交瘤细胞株,这些单抗可以分为线性、偏构象的CK-MB和CK-MM或者CK-BB交叉的单抗以及与CK-MB特异反应的偏构象型单抗,并使用偏构象型单抗研制出CK-MB定量检测试剂,该试剂与罗氏试剂相关系数r达到0.930 9。综上所述,本研究建立了研制CK-MB偏构象型特异性单抗的筛选方法,通过对所筛选的单抗进行分析鉴定并建立了CK-MB定量检测试剂,与罗氏试剂检测结果符合率高。 相似文献
1000.
目的:总结复杂型Stanford B型主动脉夹层中左锁骨下动脉重建的经验和方法。方法:2010年4月至2016年5月,共有43例复杂型Stanford B型主动脉夹层采用腔内修复术治疗,并均重建左锁骨下动脉,其中右腋动脉-左腋动脉人工血管旁路18例,开窗技术14例,烟囱技术11例。结果:均成功手术,无术中死亡,术后造影显示支架敷贴良好,定位准确,左锁骨下动脉血流通畅。术后无头晕症状,双上肢血压差均在15 mmHg之内。1例术后5天并发逆行性A型夹层猝死。肾功能衰竭2例,行透析治疗后治愈。随访38例,失访4例,随访时间2~33月(17.0士5.2月),1例患者术后45天猝死;术后3月、1年复查主动脉CTA均示支架无移位。1例I型内漏,术后8月复查CTA示内漏消失;1例术后9月人工血管内血栓形成,中段狭窄约40%;2例并发支架远端动脉瘤形成。结论:腋动脉人工血管旁路术、开窗技术、烟囱技术进行左锁骨下动脉重建,联合主动脉腔内修复术治疗复杂型Standford B型主动脉夹层,可以取得满意的临床效果。 相似文献