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981.
David Chiu Lizhi Niu Feng Mu Xiang Peng Liang Zhou Haibo Li Rongrong Li Jiazhang Ni Ningzi Jiang Yize Hu Zuofang Hao Kecheng Xu 《Cryobiology》2010,60(3):281-286
Objective: This study was designed to basic information concerning the efficacy and safety of cryosurgery for pancreatic cancer. Fifteen healthy pigs were used to perform biochemical analysis and histological assessment. Methods: Following anesthesia and laparotomy, an argon–helium cryoprobe was inserted into the pancreas. The introduction of argon gas induced a rapid decrease in temperature to ?160 °C (Group I, 5 pigs) or ?110 °C (Group II, 5 pigs), respectively, resulting in ice-ball formation of 15–20 mm diameter after 5 min. Following freezing, helium gas was circulated in the probe tip to increase the temperature to 10–20 °C over 3 min to thaw. The freeze/thaw cycle was then repeated. Group III (3 pigs) had a cryoprobe inserted, but without freezing, and Group IV (2 pigs) included untreated or normal control animals. Levels of serum amylase (AMY), IL-6 and C-RP were measured prior to freezing and for 7 days following the procedure. All pigs were euthanized 7 days post-treatment and pancreases were examined histologically. Results: Neither hyperaemia, edema or hemorrhage were observed in the un-frozen parts of the pancreas. Histological assessment revealed a significant level of necrosis in the central and lateral regions of the tissue frozen within the ice-ball. All cellular ultrastructure was destroyed and only observable as a few of remaining nuclei with broken crests and degranulated mitochondria and rough endoplasmic reticulum. There was a significant increase of serum AMY levels for a brief period in both “deep frozen” and the “shallow frozen” groups. However, the AMY also increased in two pigs in the “normal control” group and one pig from the “inserted cryoprobe without freeze” control group. All experimental pigs appeared healthy until the sacrifice time. Conclusion: Cryosurgery is a safe and effective ablative procedure for pancreatic tissue resulting in minimal complications. 相似文献
982.
983.
Predation by protozoa plays an important role in activated sludge. In this work, the kinetics for protozoan predation of active bacteria (XH), extracellular polymeric substances (EPS), and intracellular storage products (XSTO) are added into a previously expanded unified model that describes the dynamics of EPS, XSTO, and soluble microbial products (SMP). The new biomass growth–decay–predation model describes the biomass fractions, soluble organic components, and oxygen‐uptake rates considering EPS, XSTO, and predators during dynamic operating conditions in activated sludge. Model calibration using batch experimental data provides the new parameter values for predation processes and insights into mechanisms involving predators. The calibrated value of the maximum specific growth rate for the predators is much slower than for the bacteria, confirming that predators are relatively slow growers. However, the predators and bacteria have similar decay rates and dissolved oxygen affinities. Model testing with results independent of the calibration data shows two things. First, the model and calibrated parameters accurately simulate the independent results when predators are present. Second, eliminating predation by high salinity significantly lowers the OUR, and this is captured by the model. Biotechnol. Bioeng. 2010;105: 1021–1030. © 2009 Wiley Periodicals, Inc. 相似文献
984.
The phytotoxic effect of four glycoalkaloids and two 6-O-sulfated glycoalkaloid derivatives were evaluated by testing their inhibition of cucumber root growth. The bioassays were performed using both compounds singly and in equimolar mixtures, respectively. Cucumber root growth was reduced by chaconine (C), solanine (S), solamargine (SM) and solasonine (SS) with IC50 values of 260 (C), 380 (S), 530 (SM), and 610 μM (SS). The inhibitory effect was concentration-dependent. 6-O-sulfated chaconine and 6-O-sulfated solamargine had no inhibitory effects, which indicated that the carbohydrate moieties play an important role in inhibiting cucumber root growth. The equimolar mixtures of paired glycoalkaloids, both chaconine/solanine and solamargine/solasonine, produced synergistic effects on inhibition of cucumber root growth. By contrast, mixtures of unpaired glycoalkaloids from different plants had no obviously synergistic effects. The growth inhibited plant roots lacked hairs, which implied that inhibition was perhaps at the level of root hair growth. 相似文献
985.
Anh P. Truong Gergley Tóth Gary D. Probst Jennifer M. Sealy Simeon Bowers David W.G. Wone Darren Dressen Roy K. Hom Andrei W. Konradi Hing L. Sham Jing Wu Brian T. Peterson Lany Ruslim Michael P. Bova Dora Kholodenko Ruth N. Motter Frédérique Bard Pamela Santiago Huifang Ni David Chian John-Michael Sauer 《Bioorganic & medicinal chemistry letters》2010,20(21):6231-6236
In this Letter, we describe our efforts to design HEA BACE-1 inhibitors that are highly permeable coupled with negligible levels of permeability-glycoprotein activity. These efforts culminate in producing 16 which lowers Αβ by 28% and 32% in the cortex and CSF, respectively, in the preclinical wild type Hartley guinea pig animal model when dosed orally at 30 mpk BID for 2.5 days. 相似文献
986.
Li X Zhang YK Liu Y Zhang S Ding CZ Zhou Y Plattner JJ Baker SJ Liu L Bu W Kazmierski WM Wright LL Smith GK Jarvest RL Duan M Ji JJ Cooper JP Tallant MD Crosby RM Creech K Ni ZJ Zou W Wright J 《Bioorganic & medicinal chemistry letters》2010,20(24):7493-7497
HCV NS3/4A serine protease is essential for the replication of the HCV virus and has been a clinically validated target. A series of HCV NS3/4A protease inhibitors containing a novel acylsulfamoyl benzoxaborole moiety at the P1' region was synthesized and evaluated. The resulting P1-P3 and P2-P4 macrocyclic inhibitors exhibited sub-nanomolar potency in the enzymatic assay and low nanomolar activity in the cell-based replicon assay. The in vivo PK evaluations of selected compounds are also described. 相似文献
987.
Alma Dal Pozzo Ming-Hong Ni Emiliano Esposito Sabrina Dallavalle Loana Musso Alberto Bargiotti Claudio Pisano Loredana Vesci Federica Bucci Massimo Castorina Rosanna Foderà Giuseppe Giannini Concetta Aulicino Sergio Penco 《Bioorganic & medicinal chemistry》2010,18(1):64-72
Five RGD peptide–camptothecin (CPT) conjugates were designed and synthesized with the purpose to improve the therapeutic index of this antitumoral drug family. New RGD cyclopeptides were selected on the basis of their high affinity to αv integrin receptors overexpressed by tumor cells and their metabolic stability. The conjugates can be divided in two groups: in the first the peptide was attached to the drug through an amide bond, in the second through a hydrazone bond. The main difference between the two spacers lies in their acid stability. Affinity to the receptors was maintained for all conjugates and their internalization into tumor cells was demonstrated. The first group conjugates showed lower in vitro and in vivo activity than the parent drug, probably due to the excessive stability of the amide bond, even inside the tumor cells. Conversely, the hydrazone conjugates exhibited in vitro tumor cell inhibition similar to the parent drug, indicating high conversion in the culture medium and/or inside the cells, but their poor solubility hampered in vivo experiments. On the basis of these results, information was acquired for additional development of derivatives with different linkers and better solubility for in vivo evaluation. 相似文献
988.
Kristof Prinsen Junjie Li Hubert Vanbilloen Peter Vermaelen Ellen Devos Luc Mortelmans Guy Bormans Yicheng Ni Alfons Verbruggen 《Bioorganic & medicinal chemistry》2010,18(14):5274-5281
In this study, we labeled N,N′-bis(diethylenetriamine pentaacetic acid)-pamoic acid bis-hydrazide (bis-DTPA-PA) with the generator produced PET radionuclide gallium-68 and evaluated 68Ga-bis-DTPA-PA as a potential tracer for in vivo visualization of necrosis by positron emission tomography (PET). Radiolabeling was achieved with a decay-corrected radiochemical yield of 63%. Biodistribution and in vivo stability studies in normal mice showed that 68Ga-bis-DTPA-PA is cleared faster from normal tissue than the previously reported 99mTc(CO)3 complex with bis-DTPA-PA which on the other hand is more stable in vivo. 68Ga-bis-DTPA-PA showed a 3.5–5 times higher binding to necrotic tissue than to viable tissue as shown by in vitro autoradiography while no statistically significant increased hepatic uptake was found in a biodistribution study in a mouse model of hepatic apoptosis. Specificity and avidity for necrosis was further evaluated in rats with a reperfused partial liver infarction and ethanol induced muscular necrosis. Dynamic microPET images showed a fast and prolonged uptake of 68Ga-bis-DTPA-PA in necrotic tissue with in vivo and ex vivo images correlating well with histochemical stainings. With necrotic to viable tissue activity ratios of 8–15 on ex vivo autoradiography, depending on the necrosis model, 68Ga-bis-DTPA-PA showed a faster and higher uptake in necrotic tissue than the 99mTc(CO)3 analog. These results show that 68Ga-bis-DTPA-PA specifically binds to necrotic tissue and is a promising tracer for in vivo visualization of necrosis using PET. 相似文献
989.
Zhanglin Ni Michelle E. Mark Xiaokun Cai Qingcheng Mao 《International Journal of Biochemistry and Molecular Biology》2010,1(1):1-11
The human breast cancer resistance protein (BCRP/ABCG2) is a half ATP-binding cassette (ABC) efflux transporter that plays an important role in drug resistance and disposition. Although BCRP is believed to function as a homodimer or homooligomer, this has not been demonstrated in vivo in intact cells. Therefore, in the present study, we investigated dimer/oligmer formation of BCRP in intact cells. Wild-type BCRP and the mutant C603A were attached to cyan or yellow fluorescence protein and expressed in HEK293 cells by transient transfection. Protein levels, cell surface expression, and efflux activities of wild-type and mutant BCRP were determined by immunoblotting, 5D3 antibody binding, and flow cytometric efflux assay, respectively. Dimer/oligomer formation of BCRP in intact cells was analyzed using fluorescence resonance energy transfer (FRET) microscopy. Wild-type BCRP and C603A were expressed in HEK293 cells at comparable levels. C603A was predominantly expressed in the plasma membrane as was wild-type protein. Furthermore, C603A retained the same mitoxantrone efflux activity and the ability of dimer/oligmer formation as wild-type BCRP. Finally, cross-linking experiments yielded data consistent with the FRET analysis. In conclusion, we have, for the first time, demonstrated that BCRP can form a dimer/oligomer in vivo in intact cells using the FRET technique. We have also shown that Cys603 alone does not seem to be essential for dimer/oligomer formation of BCRP. 相似文献
990.
Plant species composition in green spaces within the built-up areas of Beijing,China 总被引:2,自引:0,他引:2
Juanjuan Zhao Zhiyun Ouyang Hua Zheng Weiqi Zhou Xiaoke Wang Weihua Xu Yongming Ni 《Plant Ecology》2010,209(2):189-204
Plant species composition is a critical issue in ecological research. Studies on the characteristics of plant species composition
in the built-up areas, however, are hampered by a lack of basic field-based investigation. In this article, the plant species
composition in the built-up areas of Beijing, China, is investigated using abundant field observations. The origin of species,
chorological spectra, life forms and plant communities were determined. The characteristic species in each type of green space
were determined by k-means classification, and urban plant communities were identified by two-way indicator species analysis (TWINSPAN). Plant
species composition in the built-up areas was further compared with that in natural mountain floras in Beijing to reveal the
differences in life form composition and chorological spectra, and the coincidence of species in the two communities. A total
of 618 plant species belonging to 349 genera and 103 families were identified. Our results revealed wide chorological spectra
with trees dominated by deciduous species. Although native plant species were widely distributed, 53% of the plant species
were aliens, among which 67% were introduced from America and other Asian countries. Furthermore, the characteristics of the
plant species composition in the built-up areas are significantly different from those of the natural habitats. Our results
highlight the dramatic changes in characteristics of plant species composition in the built-up area of Beijing. Several suggestions
are proposed to increase the diversity of native species through the planning and management of green spaces. 相似文献