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991.
Jean-Louis Chopart Silvia Rosa Rodrigues Mateus Carvalho de Azevedo Cristiane de Conti Medina 《Plant and Soil》2008,313(1-2):101-112
Root length density (RLD) is a key factor in crop functioning. A field method was developed to quantify RLD of sugarcane from root intersection density (RID) taking root orientations into account. RIDs were observed on three perpendicular soil planes and RLD was measured for the enclosed volume. RID and RLD of thick and fine roots were measured separately. These measurements were replicated at different ages and sites to test models describing RLD according to RID. Fine roots were nearly isotropic and thick roots had a preferential orientation, i.e. horizontal near the surface and becoming progressively vertical in deeper horizons. Relationships in thick roots were modelled according to COt: RLDt = RIDt. COt (COt: root orientation coefficient, ranged from 1.3 to 4.9 for thick roots). For fine roots (f), COf?=?2. This theoretical model led to differences between measured and calculated RLD. The ratio between measured and calculated RLDf (CEf) increased from 1 to 3 with RIDf. CEf was introduced as an additional coefficient in the model: RLDf?=?2. NIf. CEf. Intermediate results were obtained for all (a) roots: COa and CEa were both dependent on RIDa, therefore: RLDa = NIa. COa. CEa. The models were validated with independent datasets from Brazil and France. These allowed a more robust prediction of RLD than direct regressions between RID and RLD. They may estimate RLD from RID in soil profiles by root mapping while taking RLD spatial variability into account. 相似文献
992.
993.
994.
7 procarcinogens belonging to different chemical classes (nitrosamines, hydrazoalkanes, oxazaphosphorines and aromatic amines) were tested in A. nidulans for the induction of point mutations with two genetic systems (8-AG resistance and induction of methionine suppressors).
Dimethylnitrosamine, diethylnitrosamine, nitrosomorpoline, dimethyl-hydrazine, procarbazine and cyclophosphamide gave positive results with a good dose—effect relationship in the growth-mediated assay, whereas they gave negative or borderline positive results in the plate incorporation assay. 2-Aminoanthracene was completely negative with both experimental procedures.
DMN, DEN and NM were also tested for their ability to induce somatic segregation: all were positive when assayed in the growth-mediated assay. 相似文献
995.
The total amount and the composition of polar lipids of the photosynthetic bacterium Chromatium strain D grown in high (7,500 ft/c) and low (100 ft/c) incident white light were measured. Cells grown with low incident light as compared with cells grown in high incident light contained approximately 3.5 times more chlorophyll and contained significantly more internal membranes (chromatophores) as determined by electron microscopy. Nevertheless, there was approximately 40% more phospholipid in cells grown at 7,500 ft/c than in cells grown with 100 ft/c; the phospholipid composition of the cells was similar under both conditions of growth. These observations lead us to suggest that the organization and perhaps localization of the phospholipids in Chromatium may be dependent on the light intensity supplied during growth. 相似文献
996.
Lúcia R. Bertholdo-Vargas Juliana Nascimento Martins Mirian Salvador Neiva Monteiro de Barros Fiorenzo Stirpe Célia R. Carlini 《Journal of insect physiology》2009,55(1):51-58
Ribosome-inactivating proteins (RIPs) from plants inhibit protein synthesis by inactivating ribosomes. Some two-chain (type 2) RIPs are highly toxic and may play a role in plant defense. The lower toxicity of single-chain (type 1) RIPs reflects the lack of a protein domain able to bind to, and translocate the toxin across cell membranes. We studied the effect of single-chain RIPs, lychnin, momordin, gelonin, PAP-S and saporin S-6, in larvae of Anticarsia gemmatalis and Spodoptera frugiperda. After ingesting a total dose of 20 or 40 μg of the toxins, weight gain, survival rate, lesions in DNA and oxidative status (catalase and superoxide dismutase activities and lipidic peroxidation) of RIP-treated insects were assayed. Momordin was the less toxic in the biossays. S. frugiperda had a more pronounced weight loss on the 4th day of treatment and A. gemmatalis on the 10th day. RIP-induced mortality reached 57.13% for A. gemmatalis and 29.45% for S. frugiperda. RIP-treated insects showed a 2-3-fold increase in DNA lesions as assessed by the comet assay, but there were no correlations between stress markers and DNA damage. We conclude that single-chain RIPs are entomotoxic to lepidopteran insects causing extensive DNA lesions. 相似文献
997.
Peter S. Conti 《The Western journal of medicine》1994,160(5):453-454
The Council on Scientific Affairs of the California Medical Association presents the following inventory of items of progress in radiology. Each item, in the judgment of a panel of knowledgeable physicians, has recently become reasonably firmly established, both as to scientific fact and important clinical significance. The items are presented in simple epitome, and an authoritative reference, both to the item itself and to the subject as a whole, is generally given for those who may be unfamiliar with a particular item. The purpose is to assist busy practitioners, students, researchers, and scholars to stay abreast of these items of progress in radiology that have recently achieved a substantial degree of authoritative acceptance, whether in their own field of special interest or another.The items of progress listed below were selected by the Advisory Panel to the Section on Radiology of the California Medical Association, and the summaries were prepared under its direction. 相似文献
998.
Investigation of human pancreatic cancer tissues by Fourier Transform Infrared Hyperspectral Imaging
Valentina Notarstefano Simona Sabbatini Carla Conti Michela Pisani Paola Astolfi Chiara Pro Corrado Rubini Lisa Vaccari Elisabetta Giorgini 《Journal of biophotonics》2020,13(4)
Fourier‐transform infrared hyperspectral imaging (FTIR‐HSI) provides hyperspectral images containing both morphological and chemical information. It is widely applied in the biomedical field to detect tumor lesions, even at the early stage, by identifying specific spectral biomarkers. Pancreatic neoplasms present different prognoses and are not always easily classified by conventional analyses. In this study, tissue samples with diagnosis of pancreatic ductal adenocarcinoma and pancreatic neuroendocrine tumor were analyzed by FTIR‐HSI and the spectral data compared with those from healthy and dysplastic samples. Multivariate/univariate approaches were complemented to hyperspectral images, and definite spectral markers of the different lesions identified. The malignant lesions were recognizable both from healthy/dysplastic pancreatic tissues (high values of phospholipids and triglycerides with shorter, more branched and less unsaturated alkyl chains) and between each other (different amounts of total lipids, phosphates and carbohydrates). These findings highlight different metabolic pathways characterizing the different samples, well detectable by FTIR‐HSI. 相似文献
999.
P Carrieri O Ortolani A Conti P Russo 《Bollettino della Società italiana di biologia sperimentale》1979,55(22):2341-2345
A CSF electrophoresis on a particular gelatinized cellulose acetate (Cellogel RS) has been tested. The method allows the routine separation of many protein fractions in concentrated CSF in a very brief time and affords the recognition and quantification of oligoclonal banding, that is of extreme importance in the diagnosis of some neuropathies as multiple sclerosis. 相似文献
1000.
E Montali R Guazzelli M Piazzini C Conti L Papi E Lisi I Noci L Nutini F Torricelli 《Journal de génétique humaine》1987,35(2-3):195-199
We describe clinical features and laboratory findings in two azoospermic males with a large Yq deletion involving both the fluorescent and part of the non-fluorescent segment. This report give strong support to the localization of fertility factors in the euchromatic Yq portion. 相似文献