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101.
In vivo NGF deprivation reduces SNS expression and TTX-R sodium currents in IB4-negative DRG neurons 总被引:4,自引:0,他引:4
Recent evidence suggests that changes in sodium channel expression and localization may be involved in some pathological pain syndromes. SNS, a tetrodotoxin-resistant (TTX-R) sodium channel, is preferentially expressed in small dorsal root ganglion (DRG) neurons, many of which are nociceptive. TTX-R sodium currents and SNS mRNA expression have been shown to be modulated by nerve growth factor (NGF) in vitro and in vivo. To determine whether SNS expression and TTX-R currents in DRG neurons are affected by reduced levels of systemic NGF, we immunized adult rats with NGF, which causes thermal hypoalgesia in rats with high antibody titers to NGF. DRG neurons cultured from rats with high antibody titers to NGF, which do not bind the isolectin IB4 (IB4(-)) but do express TrkA, were studied with whole cell patch-clamp and in situ hybridization. Mean TTX-R sodium current density was decreased from 504 +/- 77 pA/pF to 307 +/- 61 pA/pF in control versus NGF-deprived neurons, respectively. In comparison, the mean TTX-sensitive sodium current density was not significantly different between control and NGF-deprived neurons. Quantification of SNS mRNA hybridization signal showed a significant decrease in the signal in NGF-deprived neurons compared with the control neurons. The data suggest that NGF has a major role in the maintenance of steady-state levels of TTX-R sodium currents and SNS mRNA in IB4(-) DRG neurons in adult rats in vivo. 相似文献
102.
Black GF Weir RE Chaguluka SD Warndorff D Crampin AC Mwaungulu L Sichali L Floyd S Bliss L Jarman E Donovan L Andersen P Britton W Hewinson G Huygen K Paulsen J Singh M Prestidge R Fine PE Dockrell HM 《Clinical and diagnostic laboratory immunology》2003,10(4):602-611
We have previously shown that young adults living in a rural area of northern Malawi showed greater gamma interferon (IFN-gamma) responses to purified protein derivatives (PPD) prepared from environmental mycobacteria than to PPD from Mycobacterium tuberculosis. In order to define the mycobacterial species to which individuals living in a rural African population have been exposed and sensitized, we tested T-cell recognition of recombinant and purified antigens from M. tuberculosis (38 kDa, MPT64, and ESAT-6), M. bovis (MPB70), M. bovis BCG (Ag85), and M. leprae (65 kDa, 35 kDa, and 18 kDa) in >600 non-M. bovis BCG-vaccinated young adults in the Karonga District of northern Malawi. IFN-gamma was measured by enzyme-linked immunosorbent assay (ELISA) in day 6 supernatants of diluted whole-blood cultures. The recombinant M. leprae 35-kDa and 18-kDa and purified native M. bovis BCG Ag85 antigens induced the highest percentages of responders, though both leprosy and bovine tuberculosis are now rare in this population. The M. tuberculosis antigens ESAT-6 and MPT64 and the M. bovis antigen MPB70 induced the lowest percentages of responders. One of the subjects subsequently developed extrapulmonary tuberculosis; this individual had a 15-mm-diameter reaction to the Mantoux test and responded to M. tuberculosis PPD, Ag85, MPT64, and ESAT-6 but not to any of the leprosy antigens. We conclude that in this rural African population, exposure to M. tuberculosis or M. bovis is much less frequent than exposure to environmental mycobacteria such as M. avium, which have antigens homologous to the M. leprae 35-kDa and 18-kDa antigens. M. tuberculosis ESAT-6 showed the strongest association with the size of the Mantoux skin test induration, suggesting that among the three M. tuberculosis antigens tested it provided the best indication of exposure to, or infection with, M. tuberculosis. 相似文献
103.
1. Na+ and K+ channel expression was studied in cultured astrocytes derived from P--0 rat spinal cord using whole cell patch-clamp recording techniques. Two subtypes of astrocytes, pancake and stellate, were differentiated morphologically. Both astrocyte types showed Na+ channels and up to three forms of K+ channels at certain stages of in vitro development. 2. Both astrocyte types showed pronounced K+ currents immediately after plating. Stellate but not pancake astrocytes additionally showed tetrodotoxin (TTX)-sensitive inward Na+ currents, which displayed properties similar to neuronal Na+ currents. 3. Within 4-5 days in vitro (DIV), pancake astrocytes lost K(+)-current expression almost completely, but acquired Na+ currents in high densities (estimated channel density approximately 2-8 channels/microns2). Na+ channel expression in these astrocytes is approximately 10- to 100-fold higher than previously reported for glial cells. Concomitant with the loss of K+ channels, pancake astrocytes showed significantly depolarized membrane potentials (-28.1 +/- 15.4 mV, mean +/- SD), compared with stellate astrocytes (-62.5 +/- 11.9 mV, mean +/- SD). 4. Pancake astrocytes were capable of generating action-potential (AP)-like responses under current clamp, when clamp potential was more negative than resting potential. Both depolarizing and hyperpolarizing current injections elicited overshooting responses, provided that cells were current clamped to membrane potentials more negative than -70 mV. Anode-break spikes were evoked by large hyperpolarizations (less than -150 mV). AP-like responses in these hyperpolarized astrocytes showed a time course similar to neuronal APs under conditions of low K+ conductance. 5. In stellate astrocytes, AP-like responses were not observed, because the K+ conductance always exceeded Na+ conductance by at least a factor of 3. Thus stellate spinal cord astrocyte membranes are stabilized close to EK as previously reported for hippocampal astrocytes. 6. It is concluded that spinal cord pancake astrocytes are capable of synthesizing Na+ channels at densities that can, under some conditions, support electrogenesis. In vivo, however, AP-like responses are unlikely to occur because the cells' resting potential is too depolarized to allow current activation. Thus the absence of electrogenesis in astrocytes may be explained by two mechanisms: 1) a low Na-to-K conductance ratio, as in stellate spinal cord astrocytes and in other previously studied astrocyte preparations; or, 2) as described in detail in the companion paper, a mismatch between the h infinity curve and resting potential, which results in Na+ current inactivation in spinal cord pancake astrocytes. 相似文献
104.
Identification of a nucleocapsid protein as a specific serological marker of human herpesvirus 6 infection. 总被引:8,自引:1,他引:8 下载免费PDF全文
M Yamamoto J B Black J A Stewart C Lopez P E Pellett 《Journal of clinical microbiology》1990,28(9):1957-1962
Enveloped whole virions and nucleocapsids of human herpesvirus 6 (HHV-6) strain Z29 were purified from supernatant fluids of infected human cord blood lymphocytes by filtration through polyvinylpyrrolidone-treated filters, banding on a Nycondenz step gradient, and centrifugation through two successive continuous sucrose gradients. More than 20 proteins ranging in molecular weight from less than 30,000 to more than 200,000 were identified in preparations of purified whole virions labeled with [35S]methionine and [35S]cysteine. Immunogenic virion proteins of HHV-6 were identified in immunoblot assays with human immune sera, immune sera generated from mice immunized with purified whole virions or purified nucleocapsids, and a monoclonal antibody generated from a mouse immunized with purified nucleocapsids. The sera and the monoclonal antibody reacted strongly with a 101-kilodalton protein in the immunoblots, suggesting that the protein is a component of the nucleocapsid. Human sera lacking HHV-6-specific antibodies and seropositive for one or more of the other human herpesviruses failed to react with this protein, indicating that it is a specific serologic marker for HHV-6 infection. 相似文献
105.
One contributing factor to the loss of T cells in AIDS may be the impaired ability of T cell precursors to expand, as reflected in a decreased ability of patient cells to form T cell colonies in agar. We and others have noted such a defect in people with AIDS and ARC, and have found that suppressor cells and suppressive plasma contribute to decreased T-CFC formation. We report here that the reducing agents 2-mercaptoethanol (2-ME) and n-acetyl cysteine (NAC) can enhance colony formation in vitro. In part, 2-ME can reverse the defect in T cell colony-forming cells (T-CFC) formation by overcoming the effect of suppressor cells. In a group of 46 AIDS patients, T-CFC formation was initially 42 +/- 8% (mean +/- s.e.) that of control levels. 2-ME caused an increase of 401 +/- 76% in T-CFC formation which was significantly greater than the increase in control T-CFC formation; it also significantly enhanced T-CFC formation by cells from ARC patients. Suppressor cell activity from ten AIDS patients decreased from 58 +/- 21% to 12 +/- 10% when 2-ME was added. Similar data were obtained from 14 ARC patients. NAC, a related antioxidant with low toxicity, also enhanced T-CFC in cells of AIDS and ARC patients. Vitamin C generally did not increase T-CFC formation. The data suggest that certain antioxidants such as 2-ME and NAC may be useful in treatment protocols to enhance T cell numbers in patients with AIDS or ARC. 相似文献
106.
Bovine gammadelta T cells are stimulated to proliferate by autologous monocytes. This is referred to as the autologous mixed leucocyte reaction (AMLR). It has been shown previously that the stimulatory component is constitutively expressed on the monocyte plasma membrane and is a protein or has a protein moiety. Here we showed that gammadelta T-cell responses to the monocytes requires interaction with the T-cell receptor because Fab1 fragments of a monoclonal antibody (mAb) that reacts with the delta chain of the T-cell receptor blocked proliferation in the AMLR. Monocyte molecules involved in stimulation were also characterized further by biochemical and immunological methods. A mAb, named M5, was generated by immunizing mice with bovine monocytes and shown to block the ability of monocytes to stimulate in the AMLR. Treatment of monocytes or monocyte membranes with high salt, chelating agents or phospholipase C did not affect their ability to stimulate gammadelta T-cell proliferation or reactivity with mAb M5 indicating the ability of monocytes to stimulate does not involve peripheral membrane components or a glycosyl-phosphatidylinsositol (GPI)-anchored components. Hence it was concluded that the stimulation occurred as a result of intergral membrane proteins including that recognized by mAb M5. The ligand for mAb M5 was on all bovine monocytes and to a lower level on granulocytes but not on lymphocytes. MAb M5 also reacted with sheep monocytes but not with human monocytes or murine macrophages, in agreement with a previous reports that sheep monocytes but not human or mouse mononuclear phagocytes have the capacity to stimulate bovine gammadelta T cells in in vitro cultures. The level of expression of the M5 ligand was not altered by gamma-irradiation or culture of monocytes with lipopolysaccharide but it was decreased following culture with interferon-gamma-containing cell culture supernatants. 相似文献
107.
Rapid identification and antibiotic susceptibility testing of Salmonella enterica serovar Typhi isolated from blood: implications for therapy 下载免费PDF全文
Saha SK Darmstadt GL Baqui AH Hanif M Ruhulamin M Santosham M Nagatake T Black RE 《Journal of clinical microbiology》2001,39(10):3583-3585
The turnaround time (TAT) for Salmonella enterica serovar Typhi identification and reporting of the antibiotic susceptibility profile was determined for 391 cases of typhoid fever, using the lysis direct plating or lysis centrifugation method of blood culture along with rapid antimicrobial susceptibility testing. The TAT was more rapid (TAT for 90% of the patients [TAT(90)] = 30 h; TAT(100) = 67 h) than was possible with conventional methodologies and was equivalent to that reported previously using more advanced, costly technologies that are largely unavailable in developing countries. Antibiotic susceptibility profiles, determined by the rapid antimicrobial susceptibility testing method, of randomly selected 60 S. enterica serovar Typhi isolates were identical to those determined by overnight conventional testing. Preliminary assessment of the impact of the reduced TAT on physician practices revealed that initial empirical therapy was prescribed at the time of presentation in most cases (87 of 108 [81%]) despite awareness that the final report would be available on the following day. Patients treated empirically with first-line antibiotics and shown subsequently to be infected with a multidrug-resistant strain benefited most (8 cases), since therapy was changed appropriately on the following day. In an additional 21 cases, therapy with an appropriate antibiotic was initiated after culture results were available. Thus, in approximately one-fourth (29 of 108 [27%]) of the cases, a change in management to an agent active for treatment of the isolate was made after receipt of the test results. However, in no case was therapy changed from a second-line to a first-line agent, even if the isolate was reported on the day after presentation to be sensitive to first-line therapy (33 cases). Ways in which to utilize rapid-TAT result reporting in order to positively influence physicians' prescribing in Bangladesh are the subject of ongoing research. 相似文献
108.
Chromium concentrations in serum, blood clot and urine from patients following total hip arthroplasty 总被引:2,自引:0,他引:2
Chromium released from implant alloys may be incorporated into organometallic complexes as Cr3+ [Cr(III)] or CR6+[Cr(VI)]. Since Cr(VI) is far more biologically active than Cr(III), there is considerable interest in identifying the valence state that predominates in corrosion products, either in vitro or in vivo. It is known that erythrocytes display a unidirectional uptake of Cr(VI) while effectively excluding Cr(III). Thus it was felt that a study of the chromium content of blood clot, in comparison to chromium concentrations in serum and urine, could shed light on the valency question. Fourteen patients who received conventional polymethylmethacrylate cemented cobalt-chromium alloy/ultra high molecular weight polyethylene total hip replacements as well as seven control patients who underwent orthopaedic procedures without implantation were studied. Blood and urine specimens were obtained preoperatively, post-operatively and, for total hip patients, at routine early follow up. Chromium content was determined by electrothermal atomic absorption spectroscopy. A significant post-operative rise in serum chromium content was observed for total hip replacement patients, as previously reported, but not for control patients. Unexpected day-to-day variations in clot chromium content, without significant increases, were also observed. Longer time studies are required to determine chromium valence states in corrosion products in this model. 相似文献
109.
The occurrence of hepatitis B infection as measured by sensitive serological tests for HBsAg, HBeAg and hepatitis B-specific antibodies was studied in Vietnamese refugee families. HBsAg was found in 10% of 301 children studied. Totally 74% of all HBsAg-positive children had an HBsAg-positive mother or father and an additional 7% had a positive sibling. The distribution of these cases indicated that the risk of HBs-antigenemia was increased 11-fold for those who had an HBsAg-positive mother compared with all other children. The presence of HBeAg in the HBsAg-positive parents was associated with a threefold higher risk of HBs-antigenemia in children as compared with the presence of anti-HBe. It was thus documented that HBV in this population is spread primarily by intrafamilial routes and prophylactic measures within risk families should largely be able to control the appearance of new HBsAg carriers. 相似文献
110.
Fugger EF; Black SH; Keyvanfar K; Schulman JD 《Human reproduction (Oxford, England)》1998,13(9):2367-2370
The world's first deliveries of normal babies after use of flow cytometric
separated human sperm cells (MicroSort) for preconception gender selection
are reported. Offspring were of the desired female gender in 92.9% of the
pregnancies. Most of these pregnancies and births were achieved after
simple intrauterine insemination.
相似文献