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951.
New records of marine Tardigrada in the Mediterranean Sea   总被引:1,自引:0,他引:1  
Meiofauna from Chafarinas archipelago (western Mediterranean, N. Africa) were studied, and marine Tardigrada were identified to species level. A total of 15 species, belonging to families Stygarctidae, Halechiniscidac (Subfamilies Halechiniscinae, Florarctinae, Styraconyxinae and Tanarctinae), Batillipedidae, and Echiniscoididae, were found for the first time from the Alboran Sea and southwestern Mediterranean area. Four species and one subspecies are new records for the Mediterranean Sea: I'ioractus acer, F. asper, P. stellatus, Actinarctus doryphorus and Echiniscoides sigismundi hispaniensis. The male of Floractus stellatus , previously unknown to science, is described. Many species have been recorded for the first time in different sedimentary environments, such as midlittoral pools, very shallow gravels, pools in a mixed rocky environment or between Posidonia oceanica meadows, 'Amphioxus' gravels, and coastal detritic.  相似文献   
952.
This study was done to provide an overview of the latest trichomoniasis status in Korea by finding disease clusters and analyzing temporal trends during 2012–2020. Data were obtained from the Health Insurance Review & Assessment Service (HIRA) of Korea. SaTScan and Joinpoint programs were used for statistical analyses. Gyeonggi-do had the highest average population and highest number of cases. The high incidence of T. vaginalis infections were observed among women aged 40–49 and 30–39 years (33,830/year and 33,179/year, respectively). Similarly, the 40–49 and 30–39 age group in men showed the highest average cases (1,319/year and 1,282/year, respectively). Jeollabuk-do was the most likely cluster, followed by Busan/Gyeongsangnam-do/Ulsan/Daegu and Jeju-do and Gwangju. Urban and rural differences were prominent. Trichomoniasis has decreased significantly in most clusters, except for Incheon. Trichomoniasis was decreasing in women recently after peaking around 2014. Men showed different trends according to age. Trichomoniasis was increasing in the 10–39 age groups, but decreasing in the 40–59 age groups. This study might provide an analytic basis for future health measures, policy-makers, and health authorities in developing effective system for prevention of trichomoniasis.  相似文献   
953.
在北方寒冷区,凋落物于秋季大量输入溪流,是水生生物越冬生存的关键.河床凋落物的堆积和组成会直接影响凋落叶分解等关键生态过程,但目前国内关于北方地区溪流河床凋落物分布特征的研究匮乏.在长白山地区一条源头溪流,采用原位取样的方法,探究了溪流河床凋落物的分布特征及季节动态.结果表明:深潭型凋落物斑块的堆积面积和水深显著大于浅...  相似文献   
954.
秦巴拟小鲵在河南的发现及地理分布探讨   总被引:1,自引:0,他引:1  
报道了采自河南省内乡县的一种小鲵科标本,经形态学鉴定以及DNA序列比对,确定为秦巴拟小鲵(Pseudohynobius tsinpaensis)。内乡是该物种已知分布区的东限,与已知分布点相差3个经度,呈间断分布。秦巴拟小鲵在内乡的发现可为探讨小鲵科动物的起源和演化提供重要的动物地理学依据。  相似文献   
955.
贵州草海岩溶湿地水体不同形态氮的时空分布特征   总被引:2,自引:0,他引:2  
为揭示贵州草海岩溶湿地水体中不同形态氮时空分布特征及其变化规律,通过网格布点法采集了该湿地丰、枯水期表层水,并对其不同形态溶解性氮含量进行了测定,运用ArcGIS统计模块分析了草海不同形态氮的时空分布特征,并分析了各形态氮与环境因子之间的相关性.结果表明:草海水体丰、枯水期TN的平均含量分别为(0.96±0.52)、(...  相似文献   
956.
The distribution of the macrobenthic infaunal community within the upper 25 cm of the sediment was studied at 16 stations in the lower Chesapeake Bay. Stations were located from the tidal freshwater to the polyhaline zone of major tributaries (James, York and Rappahannock Rivers) and in the polyhaline portion of the lower bay mainstem. Profiles for total number of individuals, total ash-free dry weight biomass and species encountered with depth were calculated. Except for the deep dwelling bivalve, Macoma balthica, tributary macrobenthic communities had a shallow depth distribution compared to the mainstem sites which were found in generally coarser sediments in the higher salinity region of the estuary.  相似文献   
957.
Certain parameters of the zoobenthos community structure, viz., population density, species richness, diversity, dominance and similarity indices in the inshore area (0–1 m stratum) of Lake Naini Tal were examined during 1978–1979. Significant changes in community structure were found both in space and time. A classification applied on similarity index values of the data from different sampling occasions showed two clusters of species–winter and summer clusters. Similar analysis of the sample data from different sites suggested three clusters of species for polluted water, clean water and intermediate sites. It is suggested that variation in the benthos community structure over the season is primarily related to temperature, availability of food and life cycle pattern, while its variation in space is related to sediment texture and degree of pollution.  相似文献   
958.
旨在生命机体与危险因子间建立生命物质信息对话平台,以物质化的信息,或信息化的物质的思维进行理解和推论,建立物质承载信息,信息通过物质的形式传递的思维模式,对生命信息中危险因子的属性、分类以及生命机体对危险因子的识别方式进行分析,从以上两个方面不同角度阐述危险因子与生命机体机制信息的相关互动关系。在分析与解读的过程中,主张建立合乎自然生成逻辑的科学概念,而摒弃一些主观是非逻辑所推导建立起来的概念,还原生命物质和生命过程的本来生物学位置及性质;主张一元化的思考方式和整体性理解生命信息安全控制机制的核心部分。分析结果:就生命信息中危险因子的属性和分类进行了分析,指出危险因子具有生命信息属性和生命安全属性两个属性,依据危险因子物质来源的不同,分外源性和内源性两类,绘出危险因子来源分类汇总图;从机体方面对危险因子识别方式不同,分为PRR识别方式和抗原(样)受体识别方式两类,并绘出危险因子识别方式分类汇总图。综合危险因子的属性、分类和生命机体对危险因子的识别方式,绘制出危险因子与生命机体机制信息的相关互动图,从保守性结构信息、生理产物信息、对机体损伤信息、代谢通路信息、对机体变应信息、精细纯外观构象信息及内在性核心信息7个方面对两者的相互关系进行了引证和分析,进一步阐释了生命信息安全控制机制。  相似文献   
959.
斑马鱼转座子时空表达特性   总被引:1,自引:0,他引:1       下载免费PDF全文
转座子是基因组中可移动和扩展的元件,能够插入新的位点,影响基因组和基因的结构和功能,是基因组进化的内在驱动。为探讨转座子的时空表达特性,首先通过生物信息学方法鉴定出斑马鱼9个疑似活性转座子,包括DNA转座子Tc1家族(Tc-a、Tc-b、Tc-c、Tc-d、Tc-e)、反转录转座子ERV家族(ERV-1、ERV-2)和LINE家族(L1-323、L1-21),然后采用实时荧光定量PCR法检测上述转座子在斑马鱼早期胚胎发育7个阶段及成鱼各主要脏器的表达活性。结果表明:Tc1家族在0.75、2.00、3.00 h各阶段无转录活性,在6.00、15.00、24.00、48.00 h各阶段各转座子均有较高转录活性;反转录转座子转录活性最早出现于3 h,最晚出现于15 h,且随着发育时间的延长,转录活性显著增强。9种转座子在成鱼心脏、大脑、肌肉、肝脏、睾丸和卵巢均有表达,且大脑和心脏中的表达水平显著高于其他组织,睾丸表达水平最低。分析表明转座子的表达具有时间和组织的特异性,可能参与斑马鱼胚胎和组织器官发育调控,尤其是大脑和心脏发育。这些结果为进一步研究转座子是否具有基因表达调控功能提供重要参考。  相似文献   
960.
Sorting objects and events into categories and concepts is an important cognitive prerequisite that spares an individual the learning of every object or situation encountered in its daily life. Accordingly, specific items are classified in general groups that allow fast responses to novel situations. The present study assessed whether bamboo sharks Chiloscyllium griseum and Malawi cichlids Pseudotropheus zebra can distinguish sets of stimuli (each stimulus consisting of two abstract, geometric objects) that meet two conceptual preconditions, i.e., (1) “sameness” versus “difference” and (2) a certain spatial arrangement of both objects. In two alternative forced choice experiments, individuals were first trained to choose two different, vertically arranged objects from two different but horizontally arranged ones. Pair discriminations were followed by extensive transfer test experiments. Transfer tests using stimuli consisting of (a) black and gray circles and (b) squares with novel geometric patterns provided conflicting information with respect to the learnt rule “choose two different, vertically arranged objects”, thereby investigating (1) the individuals’ ability to transfer previously gained knowledge to novel stimuli and (2) the abstract relational concept(s) or rule(s) applied to categorize these novel objects. Present results suggest that the level of processing and usage of both abstract concepts differed considerably between bamboo sharks and Malawi cichlids. Bamboo sharks seemed to combine both concepts—although not with equal but hierarchical prominence—pointing to advanced cognitive capabilities. Conversely, Malawi cichlids had difficulties in discriminating between symbols and failed to apply the acquired training knowledge on new sets of geometric and, in particular, gray-level transfer stimuli.  相似文献   
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