全文获取类型
收费全文 | 1377篇 |
免费 | 141篇 |
国内免费 | 372篇 |
出版年
2024年 | 5篇 |
2023年 | 16篇 |
2022年 | 38篇 |
2021年 | 30篇 |
2020年 | 32篇 |
2019年 | 45篇 |
2018年 | 37篇 |
2017年 | 53篇 |
2016年 | 58篇 |
2015年 | 105篇 |
2014年 | 118篇 |
2013年 | 115篇 |
2012年 | 140篇 |
2011年 | 121篇 |
2010年 | 110篇 |
2009年 | 103篇 |
2008年 | 97篇 |
2007年 | 96篇 |
2006年 | 102篇 |
2005年 | 87篇 |
2004年 | 64篇 |
2003年 | 54篇 |
2002年 | 52篇 |
2001年 | 36篇 |
2000年 | 37篇 |
1999年 | 25篇 |
1998年 | 20篇 |
1997年 | 15篇 |
1996年 | 10篇 |
1995年 | 13篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1972年 | 1篇 |
1963年 | 1篇 |
1960年 | 1篇 |
1959年 | 1篇 |
1932年 | 1篇 |
排序方式: 共有1890条查询结果,搜索用时 523 毫秒
941.
在整理保存于中国科学院植物研究所中国国家植物标本馆(PE)的国产合瓣花植物模式标本时,根据《国际藻类、菌类、植物命名法规》(墨尔本法规)规则9.5,发现在玄参科中的阿拉善马先蒿、中国马先蒿、反曲马先蒿、红毛马先蒿、粗野马先蒿、扭旋马先蒿和四川婆婆纳、在紫葳科中的密生波罗花、角蒿、烟色叶角蒿和黄花角蒿、在苦苣苔科中的东川粗筒苣苔、滇川唇柱苣苔和羽裂全盏苣苔名称的模式为合模式。遵照规则8.1、9.11和9.12,以及辅则9A.3的精神,对这14个名称做出后选模式指定。 相似文献
942.
对我国紫草科(Boraginaceae)的密花齿缘草(Eritrichium confetiflorum W. T. Wang)、锚刺果(Glochisocaryum kansuense W. T. Wang)和大花长叶微孔草(Microula trichocarpa(Maxim.) Johnst. var. macrantha W. T. Wang),唇形科(Lamiaceae)的宽叶香茶菜(Rabdosia latifolia C. Y. Wu & H. W. Li),苦苣苔科(Gesneriaceae)的矮直瓣苣苔(Ancylostemon humilis W. T. Wang)以及葫芦科(Cucurbitaceae)的黑子赤瓟(Thladiantha villosula Cogn. var. nigrita A. M. Lu & Z. Y. Zhang)原白中主模式标本引证的排印错误做了更正。密花齿缘草原白中错误地将主模式标本引证为杨昌友700422,实际应为杨昌友700442。锚刺果原白中用中文错误地将主模式标本引证为傅坤俊1989,实际应为傅坤俊1489,前者属于百合科(Liliaceae)的Asparagus sichuanicus S. C. Chen & D. Q. Liu。大花长叶微孔草原白中主模式标本引证为李馨70287,实际应为李馨72087,前者属于杜鹃花科(Ericaceae)的Rhododendron edgarianum Rehder & Wilson。宽叶香茶菜原白中主模式标本引证为曲桂龄2049,实际应为曲桂龄2046,前者属于蔷薇科(Rosaceae)的Rosa caudata Baker。矮直瓣苣苔原白中主模式标本引证为杨光辉59063,实际应为杨光辉59043,前者属于桦木科(Betulaceae)的Betula fargesii Franch.。黑子赤瓟原白中主模式标本引证为冯国楣3439,实际应为冯国楣3429,前者属于伞形科(Apiaceae)的Bupleurum rockii H. Wolff。 相似文献
943.
可转化大片段DNA载体系统主要包括双元细菌人工染色体BIBAC(binary bacterial artificial chromosome)和可转化人工染色体TAC(transformation-competent artificial chromosome)系统,它们能够高效克隆大片段DNA,在获取目的基因相关信息的同时转化植物得到转基因植株。本文综述了BIBAC和TAC载体的特点、种类、发展现状以及近年来在植物种质创新中的应用。同时,根据我国花生育种的现状,展望了可转化大片段DNA载体系统在利用野生花生资源改良栽培花生品种中的应用前景。 相似文献
944.
945.
The economic and ecological aspects of a social system are coherently linked and can be examined by its material and energy flows.In this study,we used the material flow analysis (MFA) to model the material input and output of the Wujin District of Changzhou City,Jiangsu Province in China.It was revealed that:(1) total material input and material input per capita increased with economic development,while the total material out-put and material output per capita decreased consistently;(2) except for water,the total material input continued to increase.Input of solid materials grew faster than that of gaseous materials,while the total material output declined.The gas output accounted for the largest pro-portion of the output resulting in primary environmental pollution as burned fossil fuel; (3) water use in agriculture continued with an increasing trend while that in industrial and residential sectors decreased per capita.The total wastewater discharge and wastewater discharge per capita decreased with a faster decreasing rate of residential was-tewater discharge followed by industrial wastewater dis-charge; (4) material input per unit GDP fluctuated and material output per unit GDP decreased.A decreasing trend in both water use and wastewater discharge per unit GDP was disclosed.These results suggest that the effi-ciency of resource use in the Wujin District has improved.This weakened the direct link between economic develop-ment and environmental deterioration.Additionally,we discussed the harmonic development between environ-ment and economy.Potential limitations of MFA's application were also discussed.It is suggested that effec-tive measures should be taken for the enforcement of cir-cular economic strategies and the construction of a resource-saving economy 相似文献
946.
Lee Y Kwon MK Kang ES Park YM Choi SH Ahn CW Kim KS Park CW Cha BS Kim SW Sung JK Lee EJ Lee HC 《The journal of gene medicine》2008,10(3):260-268
BACKGROUND: Glucagon-like peptide-1 (GLP-1) is a gut-derived incretin hormone that plays an important role in glucose homeostasis. Its functions include glucose-stimulated insulin secretion, suppression of glucagon secretion, deceleration of gastric emptying, and reduction in appetite and food intake. Despite the numerous antidiabetic properties of GLP-1, its therapeutic potential is limited by its short biological half-life due to rapid enzymatic degradation by dipeptidyl peptidase IV. The present study aimed to demonstrate the therapeutic effects of constitutively expressed GLP-1 in an overt type 2 diabetic animal model using an adenoviral vector system. METHODS: A novel plasmid (pAAV-ILGLP-1) and recombinant adenoviral vector (Ad-ILGLP-1) were constructed with the cytomegalovirus promoter and insulin leader sequence followed by GLP-1(7-37) cDNA. RESULTS: The results of an enzyme-linked immunosorbent assay showed significantly elevated levels of GLP-1(7-37) secreted by human embryonic kidney cells transfected with the construct containing the leader sequence. A single intravenous administration of Ad-ILGLP-1 into 12-week-old Zucker diabetic fatty (ZDF) rats, which have overt type 2 diabetes mellitus (T2DM), achieved near normoglycemia for 3 weeks and improved utilization of blood glucose in glucose tolerance tests. Circulating plasma levels of GLP-1 increased in GLP-1-treated ZDF rats, but diminished 21 days after treatment. When compared with controls, Ad-ILGLP-1-treated ZDF rats had a lower homeostasis model assessment for insulin resistance score indicating amelioration in insulin resistance. Immunohistochemical staining showed that cells expressing GLP-1 were found in the livers of GLP-1-treated ZDF rats. CONCLUSIONS: These data suggest that GLP-1 gene therapy can improve glucose homeostasis in fully developed diabetic animal models and may be a promising treatment modality for T2DM in humans. 相似文献
947.
Lee HK Woo MK Ju YI Baek SJ Song HJ Choi JS Kweon SS Jeon DY Kang YH 《Journal of microbiology (Seoul, Korea)》2008,46(2):160-164
Seroepidemological investigation of antibodies to Legionella species in 500 healthy individuals from a single geographical location in Korea was conducted by indirect fluorescent antibody assay (IFA). Considering an antibody titer of > or =1:128 as positive reaction, 15.2% of total sera were positive. In males and females older than 40 years old, levels of IgM and IgG were 1.2% and 14%, respectively. The sera with antibody titers of > or =1:128 to Legionella species accounted for 85 sera, and 9 sera of these were reacted to more than one Legionella species. Reactivity to L. bozemanii, L. micdadei, L. longbeachae, L. pneumophila sg 6, and L. gormanii were 32.9%, 20%, 15%, 10.6%, and 8%, respectively. However, L. pneumophila sg 1, sg 2, and sg 3 did not react to any sera. Serological analysis revealed that the level of antibody in response to L. bozemanii was more prevalent than L. pneumophila. Our results suggest that the antibodies of non-L. pneumophila species, such as L. bozemanii, may be highly prevalent in healthy population within Korea. Although conclusions based on the findings of this study must be cautiously considered given that the population sampled were sourced from a single province, we have added to the knowledge base of serodiagnosis of infections due to non-L. pneumophila species in Korea. 相似文献
948.
Lee JS Kim JW Choi CH Lee WK Chung HY Lee JC 《Journal of microbiology (Seoul, Korea)》2008,46(2):221-227
Acinetobacter baumannii outer membrane protein A (AbOmpA) is a major surface protein that is an important pathogen-associated molecular pattern. Based on our previous findings that AbOmpA induced the phenotypic maturation of dendritic cells (DCs) and drove the Th1 immune response in vitro, we investigated the therapeutic efficacy of AbOmpA-pulsed DC vaccines in a murine melanoma model. The surface expression of co-stimulatory molecules (CD80 and CD86) and major histocompatibility complex class I and II molecules was higher in DCs pulsed with AbOmpA alone or with a combination of B16F10 cell lysates than that of DCs pulsed with B16F10 cell lysates. AbOmpA stimulated the maturation of murine splenic DCs in vivo. In a therapeutic model of murine melanoma, AbOmpA-pulsed DCs significantly retarded tumor growth and improved the survival of tumor-bearing mice. AbOmpA-pulsed DCs significantly enhanced CD8+, interleukin-2+ T cells and CD4+, interferon-gamma+ T cells in tumor-bearing mice. These results provide evidence that AbOmpA may be therapeutically useful in adjuvant DC immunotherapy against poorly immunogenic melanoma without tumor-specific antigens. 相似文献
949.
Feit J Matyska L Ulman V Hejtmánek L Jedlicková H Jezová M Moulis M Feitová V 《Diagnostic pathology》2008,3(Z1):S10
The Hypertext Atlas of Dermatopathology, the Atlas of Fetal and Neonatal Pathology and Hypertext Atlas of Pathology (this one in Czech only) are available at http://www.muni.cz/atlases. These atlases offer many clinical, macroscopic and microscopic images, together with short introductory texts. Most of the images are annotated and arrows pointing to the important parts of the image can be activated.The Virtual Microscope interface is used for the access to the histological images obtained in high resolution using automated microscope and image stitching, possibly in more focusing planes. Parts of the image prepared in advance are downloaded on demand to save the memory of the user's computer. The virtual microscope is programmed in JavaScript only, works in Firefox/Mozilla and MSIE browsers without need to install any additional software. 相似文献
950.