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991.
This article comprises a literature analysis of 41 river rehabilitation projects to assess the short-term (5 years) ability
of indicator groups to demonstrate progress towards river rehabilitation goals. Positive indications were compared to land-use,
river size, rehabilitation intervention and time. A questionnaire was developed to investigate river manager’s interpretation
of rehabilitation success and to assess their level of adherence to recommendations in the literature with regard to rehabilitation
assessment on a conceptual level. A total of 54 responses were received from respondents based in Germany, The Netherlands
and the United Kingdom. The results indicate that macroinvertebrate indicators, while widely used in assessing river rehabilitation
efforts, exhibited a lower frequency of positive responses than most other indicator types in the short term. Conversely,
terrestrial floodplain indicators exhibited the most frequent level of positive response for all ecological type indicators
leading to recommendations for further investigations into their use for short-term monitoring. Assessment procedures recommended
in literature are largely followed, illustrating the advances that have been made with regard to assessment planning. Indicator
responses are influenced by scale factors, for example, land-use and river size, that are often not considered by rehabilitation
managers. While an emphasis is placed on ecological, hydrological and morphological indicators in monitoring schemes, the
socioeconomic perspective (emphasized in the literature as forming an integral part of the river system) is neglected. 相似文献
992.
993.
John Yeuk-Hon Chan Li Li Ji Miao Dong-Qing Cai Kenneth Ka-Ho Lee Yiu-Loon Chui 《Molecular biology reports》2010,37(1):363-368
Stress-responsive genes play critical roles in many biological functions that includes apoptosis, survival, differentiation
and regeneration. We have identified a novel stress-responsive gene called BRE which interacts with TNF-receptor-1 and blocks the apoptotic effect of TNF-α. BRE enhances tumor growth in vivo and is up-regulated in hepatocellular and esophageal carcinomas. BRE also regulates the ubiquitination of the DNA repair complex BRCC, and the synthesis of steroid hormones. Here, we examined
BRE-mRNA in cells after treatments with UV and ionizing radiation (IR). UV and IR treatment alone suppressed BRE-mRNA levels by more than 90% at 24 h, while hydroxyurea, fluorodeoxyuridine, aphidicolin, known inhibitors of S-phase DNA
synthesis, had no significant effect. BRE protein expression was unaltered in cells treated with TNF-α, Interleukin-1 and Dexamethasone, while a threefold increase
was observed following chorionic gonadotropin exposure. Although BRE plays a regulatory role in many different pathways, yet its expression is apparently under very stringent control. 相似文献
994.
Tiago Collares Vinicius Farias Campos Fabiana Kömmling Seixas Paulo V. Cavalcanti Odir A. Dellagostin Heden Luiz M. Moreira João Carlos Deschamps 《Journal of biosciences》2010,35(1):39-47
The silver catfish (Rhamdia quelen) is an endemic American fish species. The sperm of each species has its own peculiarities and biological characteristics,
which influence the success of mass DNA transfer methods. Our objective in this study was to evaluate different sperm-mediated
gene transfer (SMGT) methods to obtain transgenic silver catfish. Different treatments for the incorporation of a foreign
pEGFP plasmid group were used: (1) dehydrated/rehydrated (DR), (2) dehydrated/rehydrated/electroporated (DRE), (3) electroporated
(E), (4) incubated with seminal plasma (INC); and (5) incubated in the absence of seminal plasma (INCSP). Sperm motility,
time of activity duration (TAD), fertilization rate (FR), hatching rate (HR) and sperm morphology were also evaluated. The
polymerase chain reaction (PCR) positivity rates for the presence of the transgene were: DRE 60%; DR 40%; E 25%; INC 5% and
INCSP 25%. The rates of embryo EGFP expression were: DRE 63%; DR 44%; E 34%; INC 8% and INCSP 38%. The fertilization rate
in the control and DRE treatments groups were higher than in the DR group, but the E, INC and INCSP treatment groups had the
lowest rate. The hatching rates of the DRE, DR and control groups were higher than in the INCSP, INC and E treatment groups
(P>0.05). There were no differences among the DRE and DR, E and DR, E and INCSP groups in expression and PCR positivity rates
of enhanced green fluorescent protein (EGFP) in embryos. Scanning electron microscopy also did not show any change in sperm
morphology among treatment groups. To the best of our knowledge, this is the first report on transgene transmission of exogenous
DNA into silver catfish larvae through SMGT technology. 相似文献
995.
Anne Oxbrough Tom Gittings Thomas C. Kelly John O’Halloran 《Journal of Insect Conservation》2010,14(2):169-179
Malaise traps are typically used to sample a range of flying insect groups; however non-target taxa such as spiders may also
be collected in large numbers. In this study, spiders were sampled in peatlands and wet grasslands and catches in Malaise
and pitfall traps were compared in order to determine the adequacy of Malaise traps for use in spider biodiversity assessment.
Overall, the number of species and individuals caught in Malaise and pitfall traps were comparable, although more species
were sampled in Malaise traps in locations with a greater structural diversity of the vegetation. The spider fauna sampled
by the Malaise traps differed from that of the pitfall traps, but both methods consistently separated the species assemblages
by biotope. These results demonstrate that Malaise traps are effective at sampling spiders and indicate that they can be used
in biodiversity assessment. In addition the complementary species sampled by each method mean that employing both techniques
will be useful where a full inventory of the species is required. The authors do not suggest that Malaise traps should be
used solely to sample spiders; however, if traps are set to collect insects, identification of the spiders sampled may reduce
the need to employ additional sampling techniques. 相似文献
996.
The effects of yeheb (Cordeauxia
edulis Hemsl.) leaf extract on feeding and oviposition by diamondback moth (DBM) (Plutella xylostella L.) and the behavior of DBM parasitoid, Cotesia vestalis (Haliday), were studied. Volatile organic compounds (VOCs) from the headspace of intact and DBM-damaged broccoli plants sprayed
with yeheb extracts (YE) were also analyzed. Larval feeding and growth, and oviposition by adult DBM were strongly inhibited
by the extract. Cotesia vestalis were attracted to volatile blends from intact or DBM-damaged broccoli plants sprayed with YE over intact plants sprayed with
water or methanol. Analyses of VOCs in the headspace of broccoli plants revealed that both intact and DBM-damaged plants sprayed
with YE showed remarkable differences in sesquiterpene compounds compared to intact control treatments. These combined negative
effects of YE on DBM fitness together with positive effects on the parasitoid show that yeheb is a potential source of compounds
for use in integrated pest management to control damage caused by DBM. 相似文献
997.
Background
The Red-headed krait (Bungarus flaviceps, Squamata: Serpentes: Elapidae) is a medically important venomous snake that inhabits South-East Asia. Although the venoms of most species of the snake genus Bungarus have been well characterized, a detailed compositional analysis of B. flaviceps is currently lacking. 相似文献998.
Antifungal drug resistance significantly impacts treatment outcomes in patients with invasive fungal infections (IFIs). Although
primary (intrinsic) resistance may occur independent of previous therapy, prior concomitant antifungal exposure increases
the risk for secondary (acquired) resistance and subsequent colonization or infection with less-susceptible pathogens. Among
various pathogen-antifungal combinations, this effect has been best studied clinically with azole exposure and the risk of
Candida spp. with reduced susceptibility. The rapid development of secondary resistance to flucytosine in Candida spp. has limited its use as monotherapy. Secondary resistance to amphotericin B is infrequent. In contrast, secondary resistance
in Aspergillus spp. is less of a concern. Recent reports of secondary resistance in patients receiving fluconazole for cryptococcal infections
may justify susceptibility testing in the setting of prior therapy or treatment failure. Despite numerous patient-focused,
drug-focused, and disease-focused strategies to improve treatment outcomes, clinical resistance (manifesting as treatment
failures despite adequate antifungal therapy) continues to be problematic in patients with serious IFIs. 相似文献
999.
Data on benthic macroinvertebrate assemblages of two alpine lakes in the Tatra Mts (Slovakia) collected in 1914, 1933, 1979–1982,
1993–1997, and 2000 were collated and analysed in an attempt to define their relationship to major environmental events affecting
these alpine lakes over the last century. The oldest data were considered an important background before the onset of acidification
in one of the lakes in the 1950s, while the most current contain possible information on biological recovery. Results show
that data from the 1910s are insufficient to characterize the macroinvertebrate fauna. Deep zone assemblages of both studied
lakes have remained stable since the 1930s. Changes in the density of dominant species over time were found in the acidified
lake, suggesting a connection between an increase in phosphorus and chlorophyll-a concentration. The composition of the littoral assemblages in the acidified lake in the 1930s indicates that the lake was
not strongly acidified at that time. A stable composition since the 1980s reflects the ongoing acid stress. Incomplete species
data on the non-acidified lake did not allow us to detect possible changes in the littoral fauna related to acidification.
Single findings of species indicating a recovery process need longer-term data to confirm such a trend. Results from this
study suggest that historical datasets consist of valuable information that can supplement palaeolimnological analyses in
the reconstruction of lake ontogeny. 相似文献
1000.
Plants are able to plastically respond to their ubiquitously heterogeneous environments; however, little is known about the
conditions under which plants are expected to avoid or confront their neighbors in dense stands, where heterogeneity is self-generated
by non-uniform growth and feedback between plant interactions and stand heterogeneity. We studied the role of plasticity for
spatial pattern-formation and the resulting stand-level fitness of clonal plants, assuming variable types of plastic behavior.
Specifically, the adaptive values of behavior ranging from pure avoidance, to neutral and pure confrontation were assessed
using a simulation model of stands of clonally growing plants with varying capacity of plastic behavior. The results demonstrated
significant effects of the type of competitive behavior on mean final densities of single-species stands at equilibrium. Density
was the lowest and aggregation was the highest in stands of purely confrontational plants, and density was highest in stands
of neutral and purely avoiding plants. When competing against a neutral photometer (i.e. non-plastic but otherwise identical
plant), the best competitors were plants that avoided their neighbors in 0.33–0.50 of the cases and were neutral otherwise.
Differences in adaptive values of individual behaviors depended both on the distance over which the environmental structure
(i.e. local density) was perceived, and on overall density. Density-independent ramet mortality profoundly changed the effectiveness
of competitive behaviors. Under high levels of mortality, avoidance was the most effective and confrontation the least effective
behavior. The results indicate that individual-based behaviors might affect higher organizational levels, and that their reciprocal
interactions with resource levels and patchiness, and responsiveness to density-independent mortality might generate higher-order
feedbacks that intricately affect the fate of individual ramets and the patterning of whole stands and communities. 相似文献