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11.
Summary A quantitative evaluation has been made of the sizes of neuronal granular vesicles (GV) in different (sub-)zones of the rat median eminence. On the basis of the frequency distribution of the mean sizes of the GV in the individual nerve profiles, at least 4 tentative categories of nerve profiles may be distinguished. However, available data do not permit characterization of nerve fibre categories in terms of neurohormone and/or neurotransmitter storage. From dorsal to ventral the palisade zone shows a decrease in mean size of GV; furthermore, the relative number of nerve profiles characterized by small GV (mean size smaller than 112 nm) increases. In contrast, the GV in the zona granulosa, that part of the external zone of the median eminence ventral to the palisade zone, are of relatively large size. Qualitative observations indicate that the zona granulosa may be regarded as an area for both storage and release of biologically active substances. We are grateful to Mrs. R.M.Y. Hartsteen for technical assistance, to Miss P.C. Delfos and Mr. W. van den Oudenalder for photographic assistance and to Prof. J. Moll for helpful criticism.  相似文献   
12.
Abstract The growth, biomass δ13C values, and ability to accumulate titratable acidity at night were compared in eight environmental treatments for Cremnophila linguifolia, Sedum greggii, and their F1 hybrid. In the phytotron, differences in treatment daylength, day/night temperature and water availability were all found to have effects on total plant dry weight, nocturnal accumulation of titratable acidity and biomass δ13C value of at least some of the genotypes. However, there were differences between the genotypes both in the magnitude and direction of response of the phenotypic properties to the treatment variables. The phytotron δ13C values ranged from -12.9 to -19.2‰ for C. linguifolia, from -22.2 to -33.4‰ for S. greggii, and from -19.2 to -24.9‰ for the hybrid. After with-holding water for 76 h both C. linguifolia and the hybrid had midday Ψleaf values of -0.23 MPa; however, S. greggii had a value of -1.05 MPa. In contrast to past observations of other species, the daily watered plants of C. linguifolia had less negative δ13C values than did the plants watered only weekly.  相似文献   
13.
Zusammenfassung Die serotoninhaltigen, nach Formaldehydbedampfung im UV-Licht gelbfluoreszierenden EC-Zellen im Magendarmepithel wurden bei normalen und bei tryptophanfrei ernährten Ratten untersucht. Bei Kontrolltieren ist die Zahl der EC-Zellen, bezogen auf die Schleimhautfläche, im Duodenum größer als im Pylorus. Im Duodenum sind die EC-Zellen etwa gleichmäßig auf Oberflächen- und Drüsenepithel verteilt, im Pylorus ganz überwiegend im Drüsenepithel lokalisiert. Die Brunnerschen Drüsen besitzen keine EC-Zellen. Tryptophanfreie Diät führt zu starker Abnahme des Serotoningehalts der EC-Zellen, nach Umsetzung auf Normalkost steigt er wieder an. — Die Ergebnisse sprechen weiterhin dafür, daß die EC-Zelle sowohl Speicher- als auch Syntheseort von Serotonin ist. Dabei kommt Serotonin in der EC-Zelle wahrscheinlich in zwei Fraktionen vor, nämlich zytoplasmatisch gelöst und granulagebunden. Die histochemischen Nachweismethoden für Serotonin, Möglichkeiten des Eingriffs in die verschiedenen Syntheseschritte des Serotonins und deren Spezifität in bezug auf die EC-Zelle als physiologischem Ort der Serotoninsynthese werden diskutiert.
Studies on the endocrine cells of the gastrointestinal tractII. Fluorescence microscopy of the EC-cells after tryptophan-free diet
Summary The serotonin-containing EC-cells of the gastro-intestinal mucosa, which show yellow fluorescence after treatment with gaseous formaldehyde, were investigated in the rat after normal and tryptophan-free nourishment. In control animals the number of EC-cells, related to epithelium area is higher in the duodenum than in the pyloric region. In the duodenum the EC-cells show about the same distribution in surface epithelium and gland epithelium. In the pyloric region EC-cells are localized predominantly in the gland epithelium. No EC-cells were found in the Brunner glands. After tryptophan-free diet the serotonin-level of the EC-cells strongly decreases; serotonin-level increases after return to normal nourishment. The results also suggest, that serotonin is synthesized as well as stored in the EC-cell and that it occurs in two fractions: bound to granules and dissolved in the cytoplasm. Discussion deals with the histochemical methods for determination of serotonin, the possibilities of influencing the pathways of serotonin metabolism and the specificity of these possibilities concerning the EC-cell as the physiological site of serotonin synthesis.
Mit Unterstützung durch die Deutsche Forschungsgemeinschaft, Antrag Fo 77, 1–4.  相似文献   
14.
The liver is more prone to infections that cause fibrosis, such as steatosis, non-alcoholic steatohepatitis, hepatotoxicity, cirrhosis, and hepatocellular carcinoma. Also, Viral hepatitis is a common condition worldwide it worsens into chronic inflammation of the liver. One of the healthiest fruits is the pomegranate for the body and health, as it contains a high nutritional value of minerals, vitamins, antioxidants, so we worked on this investigation to magnify the therapeutic applications of pomegranate fruits (POF) and peel (POP) in carbon tetrachloride-injected rats (Ccl4). The experiment was carried out in a caged animal. All rats were fed a basal diet for one week before the study, and they were divided into seven groups, each with six rats. As a control negative group (C–ve), the first group sample was fed only the basal diet for 28 days. The remaining rats (n = 36) were injected with carbon tetrachloride (Ccl4). Five groups were fed varying concentrations of (5 %, 10 %, 15 % POF, 5 %, and 10 % pomegranate peel (POP)), whereas one group was diagnosed with the illness and disease, and didn't even feed the experimental diet. The results revealed significant increases in T.BIL, D.BIL, and BIL in the serum of rats injected by CC14 to induce hepatopathy compared to the healthy group (normal rats). Also, the best treatment considering the serum D.BIL was recorded for the 5 % POF.  相似文献   
15.
Risk assessments often rely on deterministic models using long-term averages or “steady-state” values of input variables. Such models do not provide the information needed to estimate acute exposures. This study uses extreme value theory to examine the frequency and magnitude of daily pollutant concentrations in surface soils predicted at six U.S. locations. Concentrations are predicted using a deposition-leaching model and 50 years of historical precipitation data. A stochastic model also is used to generate 1000 years of precipitation data as modeling inputs for each location. The annual maximum concentrations at each site are fitted to a Gumbel type I distribution to estimate occurrence probability. For soluble pollutants, the predicted concentration varied substantially with precipitation, and the maximum daily concentrations exceeded annual averages by 4 to 8 times. Observed and synthetic precipitation data produced similar results at most study locations, though the synthetic data provided a slightly better fit to the Gumbel type I distribution. The precipitation model allows the generation of representative precipitation data that extend limited historical records. The extreme value analysis facilitates the evaluation of maximum pollutant concentrations, return periods, and other statistics that are important in evaluating acute exposures.  相似文献   
16.
基于价值评估的黄山市生境质量时空演变特征分析   总被引:2,自引:0,他引:2  
彭建  吴见  徐飞雄  吕俭 《生态学报》2021,41(2):665-679
评价与分析特定区域的生境质量及其时空变化对其生态安全格局构建、可持续发展意义重大。本文以典型旅游城市黄山市为研究区,综合生态系统服务价值评价模型、基于NPP与NDVI的生境质量指数评价、InVEST生境质量评价模型、空间分析等模型与方法对黄山市1987-2017年生境质量进行研究。结果表明:(1)1987-2007年,黄山市生境质量总值持续下降,2017出现回升,但生境受到的威胁仍增加,生境最优区为北部太平湖区域,生境质量低值主要分布在各县区主城区;生境质量栅格等级变化以4等级转变为3等级为主。(2)1987-2017年,黄山市105个乡镇(街道)中有84个乡镇(街道)生境质量有所下降,主要分布在东部区域;北部环太平湖区域的乡镇为生境质量"高高"型聚集区及热点区域,屯溪区、徽州区南部、歙县、休宁县主城区的各镇为生境质量"低低"型聚集区及冷点区域。(3)黄山市城市发展对生境质量影响较大,大体上距离城市中心点越近的圈层,生境质量越差;距离黄山市旅游中心点10-20、30-40、40-50 km的3个圈层形成生境质量低值点,为旅游与城区互助发展的结果;黄山市旅游与生境质量空间分布相关性较强,旅游设施、景区核密度越高,低等级生境质量占比越高。  相似文献   
17.
马勇  凌旋  童昀 《生态学报》2021,41(19):7542-7554
以典型旅游城市三亚市为案例地,利用2006-2018年4期Landsat遥感影像数据,借助ENVI、ArcGIS平台定量识别土地利用演变特征,在1km×1km格网尺度下估算旅游地生态系统服务价值,并结合空间探索性数据分析揭示生态系统服务价值时空分异特征及其与旅游地发展的时空耦合关系。结果表明:(1)2006-2018年间,三亚市生态系统服务价值总量呈逐年下降趋势,由6.73×109元降至5.76×109元,累计减少9.78×108元;(2)空间格局上,三亚市呈"南低北高"空间分异格局,2006-2018年增值区域连片分布于崖州区、天涯区、吉阳区南部区域,且呈逐年减少趋势,减值区域集聚于天涯区东北部、海棠区;(3)空间集聚上,生态系统服务价值截面各年份均呈显著空间正相关且相关性先降后增。高高集聚区位于天涯区北部区域,低低集聚区分布于沿海、海湾地区;(4)旅游发展与生态系统服务价值时空演化特征关联性较强。三亚市天涯区北部林地生态环境良好,生态系统服务价值略有下降但绝对数值稳定,是生态系统服务价值主要来源;旅游发展较为迅速的三亚湾、崖州湾以及海棠湾,相对增值区域较多,但绝对生态系统服务价值损失显著,严重滞后于其他区域。  相似文献   
18.
The wolfberry (Lycium barbarumL.) fruit has been used in traditional Chinese medicine and food, but fruits grown in various geographic areas are significantly different in quality and content of functional components. In this study, we tested the internal nutritional ingredients and related environmental factors using forty-two wolfberry fruits collected from seven wolfberry producing regions in China (Yinchuan and Zhongning in Ningxia, Jingyuan in Gansu, Nuomuhong Farm in Qinghai,Hangjinhouqi and Wulateqianqi in Inner Mongolia, and Jinghe in Xinjiang). The nutritional ingredients of the forty-two wolfberry fruits are dependent on the environment. Correlation analysis revealed that the amount of nutrients was highly related to each other. Based on the analysis ofratio of total sugar to betaine (sugar-alkali ratio), we have successfully established quality standards for the wolfberry based on the levels of betaine and sugar. The standards were as follows: high betaine low sugar (sugar-alkali ratio≤15.1), high betaine medium sugar (15<sugar-alkali ratio≤60), medium betaine medium sugar (60<sugar-alkali ratio≤121), medium betaine high sugar (121<sugar-alkali ratio≤165), and low betaine high sugar (sugar-alkali ratio>165). Zhongning of Ningxia is the geo-authentic producing region of the wolfberry, whereby the wolfberries are rich in main pharmacological ingredients Lycium barbarum polysaccharide (LBP) and three trace elements (iron, manganese and selenium) and medium sugar-alkali ratio. In addition, the correlation analysis showed that both the altitude and average temperature difference between day and night had positive effects on the wolfberry flavonoids content but the annual sunshine duration negatively affected the betaine contents of the wolfberry fruit.  相似文献   
19.
The kinetic properties of rat liver nuclear lysozyme, earlier purified to homogeneity in our laboratory, have been studied. The enzyme was found to be maximally active in the pH range 4.2 to 5.4 in 0.02 M buffer. Its Km was found to be 333 mg/litre. It was heat sensitive even in the acidic pH range. The enzyme exhibited tissue specific differences when compared with the rat kidney nuclear lysozyme.  相似文献   
20.
Despite widespread and its local available as a naturalized hedge and shade plant, the potential of Trichilia emetica was not utilized in soap making by the majority of local community in various parts of Dodoma, Tanzania. This study aimed to assess the quantity (yields) and quality (Acid Values (AVs), %Free Fatty Acids (%FFAs) and Saponification Values (SVs) of seed oil from water plant (T. emetica), suitable for soap making application. Solvent extraction method was used during oil extraction, where by 50gm of preheated and powdered seed materials were immersed in 250 ml of n-hexane in 1:5 (w/v) to dissolve the oil contained in the seed cake. The oil was collected by vaporizing solvent out through Rotary evaporation at 60 °C. Also standard titration methods were used to obtain SVs, AVs and %FFAs of the extracted oil. Results showed that T. emetica seeds contained higher quantity of oil (48.4%−50.2%) than many reported commercial plant seed oils. Also, the study found higher AV (7.4 mgKOH/g−7.8 mgKOH/g), %FFA (3.7% to 3.9%) and SVs (189.5 mgKOH/g 191.4 mgKOH/g) than the maximum acceptable limits of 0.50 mg KOH/g, 0.020% and 175 mgKOH/g − 187 mgKOH/g prescribed by ASTM standards (2002). The obtained results showed that, T. emetica seeds yielded high oil quantity with low qualities due to higher levels of acidity. But high SVs guarantees the possibility of using T. emetica seed oil in soap making. However, the oil requires purification in order to bring levels of acidity to acceptable standards and guarantee its normal use in soap making.  相似文献   
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