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941.
Gaia Nebbia Dimitra Peppa Anna Schurich Pooja Khanna Harsimran D. Singh Yang Cheng William Rosenberg Geoffrey Dusheiko Richard Gilson Joanne ChinAleong Patrick Kennedy Mala K. Maini 《PloS one》2012,7(10)
The S-type lectin galectin-9 binds to the negative regulatory molecule Tim-3 on T cells and induces their apoptotic deletion or functional inactivation. We investigated whether galectin-9/Tim-3 interactions contribute to the deletion and exhaustion of the antiviral T cell response in chronic hepatitis B virus infection (CHB). We found Tim-3 to be expressed on a higher percentage of CD4 and CD8 T cells from patients with CHB than healthy controls (p<0.0001) and to be enriched on activated T cells and those infiltrating the HBV-infected liver. Direct ex vivo examination of virus-specific CD8 T cells binding HLA-A2/peptide multimers revealed that Tim-3 was more highly upregulated on HBV-specific CD8 T cells than CMV-specific CD8 T cells or the global CD8 T cell population in patients with CHB (p<0.001) or than on HBV-specific CD8 after resolution of infection. T cells expressing Tim-3 had an impaired ability to produce IFN-γ and TNF-α upon recognition of HBV-peptides and were susceptible to galectin-9-triggered cell death in vitro. Galectin-9 was detectable at increased concentrations in the sera of patients with active CHB-related liver inflammation (p = 0.02) and was strongly expressed by Kupffer cells within the liver sinusoidal network. Tim-3 blockade resulted in enhanced expansion of HBV-specific CD8 T cells able to produce cytokines and mediate cytotoxicity in vitro. Blocking PD-1 in combination with Tim-3 enhanced the number of patients from whom functional antiviral responses could be recovered and/or the strength of responses, indicating that these co-inhibitory molecules play a non-redundant role in driving T cell exhaustion in CHB. Patients taking antivirals able to potently suppress HBV viraemia continued to express Tim-3 on their T cells and respond to Tim-3 blockade. In summary, both Tim-3 and galectin-9 are increased in CHB and may contribute to the inhibition and deletion of T cells as they infiltrate the HBV-infected liver. 相似文献
942.
Cloudwater Inputs of Nitrogen to Forest Ecosystems in Southern Chile: Forms, Fluxes, and Sources 总被引:6,自引:0,他引:6
Nitrogen (N) has been considered a limiting nutrient to many aquatic and terrestrial ecosystems. However, human activity has
resulted in increased atmospheric N deposition worldwide such that N pollution is now altering ecosystem function in many
locations. Research on atmospheric deposition has focused primarily on inorganic nitrogen (DIN; NH4
+-N + NO3
−-N) via rainwater and dry deposition as the main N input to ecosystems. Recently, organic N (ON) has been shown to be an important
constituent in rainwater or dry deposition. Here we show that ON dominated (66%) total N in cloudwater from a remote site
in southern Chile. Cloudwater from more human-impacted sites in northeastern USA had lower ON concentrations and DIN was dominant.
We estimate that cloudwater delivers up to 2 kg ha−1 DIN and 9 kg ha−1 ON annually, compared to less than 1 kg ha−1 of DIN deposition via rainwater, thus it may contribute substantially to the N-economy of Chilean coastal forests. We also
suggest that the adjacent ocean, where biologic productivity is high, may be a major source of N in Chilean cloudwater. This
proposed marine-terrestrial flux via cloud deposition has not previously been identified and may be an example of the ocean
feeding the forest. We suggest that this type of cross boundary flux may be common in other upwelling zones, such as along
the west coasts of Africa, North and South America and east India, and warrants further substantiation and investigation.
Received 30 June 2000; accepted 18 October 2000 相似文献
943.
944.
945.
Sebastian Patzke Sambra Redick Abdirashid Warsame Carlos A. Murga-Zamalloa Hemant Khanna Stephen Doxsey Trond Stokke 《Molecular biology of the cell》2010,21(15):2555-2567
We described previously the cell cycle- and microtubule-related functions of two splice isoforms of the centrosome spindle pole-associated protein (CSPP and CSPP-L). Here, we show that endogenous CSPP isoforms not only localize to centrosomes and the midbody in cycling cells but also extend to the cilia axoneme in postmitotic resting cells. They are required for ciliogenesis in hTERT-RPE1 cells in vitro and are expressed in ciliated renal, retinal, and respiratory cells in vivo. We report that CSPP isoforms require their common C-terminal domain to interact with Nephrocystin 8 (NPHP8/RPGRIP1L) and to form a ternary complex with NPHP8 and NPHP4. We find CSPP-L to be required for the efficient localization of NPHP8 but not NPHP4 to the basal body. The ciliogenesis defect in hTERT-RPE1 cells is, however, not mediated through loss of NPHP8. Similar to the effects of ectopical expression of CSPP-L, cilia length increased in NPHP8-depleted cells. Our results thus suggest that CSPP proteins may be involved in further cytoskeletal organization of the basal body and its primary cilium. To conclude, we have identified a novel, nonmitotic function of CSPP proteins placing them into a ciliary protein network crucial for normal renal and retinal tissue architecture and physiology. 相似文献
946.
S. Khanna 《World journal of microbiology & biotechnology》1993,9(5):559-561
Glucose uptake by whole-cell suspension of the facultative anaerobe Cellulomonas fimi, which was two-fold higher under aerobic conditions than under N2 or H2, was inhibited by inhibitors of electron transport and ATP synthesis and, particularly, by proton and metal ion ionophores. A variety of sugars, including 2-deoxyglucose, did not inhibit glucose uptake but cellobiose was a non-competitive inhibitor. Cells grown on cellobiose medium transported glucose at one half the rate of glucose-grown cells. Cellulomonas fimi has a highly specific active system for glucose transport. 相似文献
947.
948.
Shruti Khanna Maria J. Santos Erin L. Hestir Susan L. Ustin 《Biological invasions》2012,14(3):717-733
Eradicating or controlling invasive alien species has frequently had unintended consequences, such as proliferation of other
invasive species or loss of ecosystem function. We explore this problem using a case study of a highly invasive floating aquatic
macrophyte, water hyacinth (Eichhornia crassipes), in the Sacramento-San Joaquin Delta of California. We used 5 years of remote sensing data to perform change detection analysis
to study plant community dynamics contemporaneous with changes in water hyacinth cover. Our results show that as water hyacinth
cover decreased, submerged aquatic plant (SAP) cover increased and vice versa. This effect was strongest in large patches
of water hyacinth. We found no evidence that the native floating aquatic species, pennywort (Hydrocotyle umbellata), benefitted from reducing cover of water hyacinth. In most years, pennywort cover either showed no trend or followed the
same trajectory as water hyacinth cover. In this study a decrease in cover of water hyacinth most often resulted in colonization
by SAP species with some habitat returning to open water. 相似文献
949.
R Husain V K Khanna S I Zaidi S A Mall M M Husain B M Gupta P K Seth 《Journal of biological regulators and homeostatic agents》1991,5(1):19-22
A single i.p. administration of an immunomodulatory agent 6-MFA (a biological response modifier and antiviral agent of fungal origin, 10 mg/100g b.wt.), on 5th day of repeated acrylamide (ACR, 50 mg/kg b.wt.) treatment significantly protected rats against its specific neurotoxic effects. Corpus striatal 3H-spiperone binding elevated (24%) while glutathione-S-transferase (GST) activity decreased (33%) in ACR group but values were markedly restored in 6-MFA alone and co-exposed group. Development of hind limb paralysis was also protected by 6-MFA. Results warrant the possible involvement of immune mechanisms and certain other factors such as lymphokines, hormones and microglia at the target site, which in turn facilitate the repair mechanism suggesting a therapeutic role of 6-MFA in clinical cases of toxic neuropathies in future. 相似文献
950.
Sergey Ya. Reznik Nina P. Vaghina Natalia D. Voinovich 《Biocontrol Science and Technology》2012,22(4):429-445
Maternal photoperiodic response is known to influence the percentage of diapausing prepupae in Trichogramma species. However, the influence of several preceding generations has not yet been studied. We have investigated the stability of photoperiod-induced changes in multiple generations of Trichogramma buesi Voegele and Trichogramma principium Sug. et Sor. Short-day conditions during preimaginal development induced an increase in the percentage of diapausing progeny and grand progeny of both Trichogramma species. A similar trend was also detected in the fourth and fifth generations, but the response was weak although statistically significant. This grand-grandmaternal photoperiodic effect (which has not been demonstrated before for Trichogramma or for any other insect parasitoid) is most probably based on the transgenerational transmission of variations in DNA expression. We conclude that in mass rearing, to facilitate diapause induction before cold storage, it is advisable to rear both maternal and grandmaternal generations under the short-day conditions. In scientific studies, several generations preceding the experiment should be kept under equal conditions to exclude multigenerational maternal effects. 相似文献