全文获取类型
收费全文 | 9494篇 |
免费 | 774篇 |
国内免费 | 198篇 |
专业分类
耳鼻咽喉 | 100篇 |
儿科学 | 181篇 |
妇产科学 | 389篇 |
基础医学 | 1227篇 |
口腔科学 | 199篇 |
临床医学 | 1006篇 |
内科学 | 1953篇 |
皮肤病学 | 150篇 |
神经病学 | 631篇 |
特种医学 | 296篇 |
外科学 | 1380篇 |
综合类 | 333篇 |
现状与发展 | 1篇 |
一般理论 | 2篇 |
预防医学 | 452篇 |
眼科学 | 192篇 |
药学 | 990篇 |
4篇 | |
中国医学 | 193篇 |
肿瘤学 | 787篇 |
出版年
2023年 | 92篇 |
2022年 | 144篇 |
2021年 | 284篇 |
2020年 | 185篇 |
2019年 | 286篇 |
2018年 | 317篇 |
2017年 | 215篇 |
2016年 | 201篇 |
2015年 | 315篇 |
2014年 | 386篇 |
2013年 | 508篇 |
2012年 | 676篇 |
2011年 | 782篇 |
2010年 | 489篇 |
2009年 | 387篇 |
2008年 | 553篇 |
2007年 | 555篇 |
2006年 | 516篇 |
2005年 | 499篇 |
2004年 | 430篇 |
2003年 | 351篇 |
2002年 | 316篇 |
2001年 | 255篇 |
2000年 | 215篇 |
1999年 | 182篇 |
1998年 | 86篇 |
1997年 | 62篇 |
1996年 | 50篇 |
1995年 | 79篇 |
1994年 | 69篇 |
1993年 | 59篇 |
1992年 | 129篇 |
1991年 | 101篇 |
1990年 | 95篇 |
1989年 | 61篇 |
1988年 | 61篇 |
1987年 | 66篇 |
1986年 | 34篇 |
1985年 | 37篇 |
1984年 | 44篇 |
1983年 | 27篇 |
1982年 | 25篇 |
1981年 | 17篇 |
1980年 | 18篇 |
1979年 | 24篇 |
1978年 | 18篇 |
1976年 | 19篇 |
1975年 | 18篇 |
1973年 | 16篇 |
1972年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
Reports of the incidence of postoperative deep vein thrombosis in the Chinese population of Taiwan are few in the literature. Over a 3 year period, the fibrinogen degradation products test, the pulse volume recorder, and venography were used to study 220 patients undergoing major operations at the Veterans General Hospital in Taipei, Taiwan. Deep vein thrombosis was found in 17 patients (7.7 percent). A comparison of the three diagnostic methods showed that the sensitivities of the fibrinogen degradation products test and the pulse volume recorder were 56.3 percent and 93.7 percent, respectively; the specificities, 97.4 percent and 95.7 percent, respectively; and the accuracies, 85.5 percent and 95.5 percent, respectively. These results support the combined use of the fibrinogen degradation products test and the pulse volume recorder for screening and diagnosing deep vein thrombosis. 相似文献
22.
Two Puralpha-binding proteins (PurBPs) were found in nuclear extract from mouse brain during P4-P10 by the overlay assay. At P14, they were decreased significantly in nuclear extract and increased in the S3 fraction, indicating their dynamic translocation during development. Western blot analysis also demonstrated concomitant translocation of Puralpha with the PurBPs during P7-P14, when neuronal circuit proceeds. Immunocytochemical study with cultured hippocampal neurons from rat E18 confirmed that nuclear Puralpha was translocated to cytoplasm after plating for 7-14 days. These results suggest that spatiotemporal translocation of Puralpha with the PurBPs from nuclei to cytoplasm has a crucial role in neuronal development. 相似文献
23.
The role of serotonin and glutamate release in dorsal medulla (DM) for regulation of systemic arterial pressure (SAP) was examined with microdialysis and high performance liquid chromatograph in anesthetized cats. KCl-perfusion in DM increased serotonin and glutamate concentrations in DM. Perfusion of serotonin resulted in decreases in glutamate concentration and SAP. Perfusion of alaproclate, a serotonin reuptake inhibitor that produced an increase in serotonin concentration in DM, had the same results as perfusion of serotonin. In conclusion, serotonin and glutamate appeared to be tonically and endogenously released from nerve terminals in DM, and the decrease in SAP could be attributed to the decreased glutamate release resulting from inhibitory action of serotonin in DM. The putative roles of serotonin and glutamate in DM may be important in SAP regulation. 相似文献
24.
This study was conducted to investigate whether there are differences in the autonomic nervous system function of chickens from lines selected for high (HWS) or low body weight (LWS). The cardiovascular response to various pharmacological agents was used as an indicator of autonomic nervous system response. Ten individuals from each line and sex were used in the study. Catheters were introduced into the left brachial artery and vein and connected to a MP100-BIOPAC system to record blood pressure and heart rate (HR). Chickens were injected with phenylephrine, atropine, propranolol, and tetraethylammonium chloride (TEAC). The LWS birds exhibited a greater increase in mean arterial blood pressure (MABP) and a lesser increase in HR than the HWS birds following atropine. The response to atropine showed a line and sex interaction in which male birds had a greater increase in HR than females and LWS females had a lower increase in HR than the HWS females. Injection of phenylephrine following pretreatment with atropine caused a baroreceptor reflex in which males showed a greater decrease in HR than females. In response to the beta-adrenergic receptor blocker propranolol, females displayed a greater decrease in MABP than males and LWS birds had a greater decrease in HR than HWS birds. In response to the autonomic ganglionic blocker TEAC, MABP and HR decreased equally in both lines. The percentage of adrenal and sympathetic impact on regulation of HR showed that LWS females required greater adrenal activity than those from the other subclasses. Although changes in HR and MABP ratios in response to phenylephrine were different between lines, these responses were not different when phenylephrine was given following atropine. This pattern of response suggested that HWS birds had greater parasympathetic nervous system activity in order to maintain cardiovascular function. These results demonstrate that selection for HWS or LWS has resulted in greater parasympathetic and sympathetic nervous system tone in birds from the HWS and LWS birds, respectively, and suggest that differences between the lines could be at the level of the chromaffin tissue in the adrenal gland. 相似文献
25.
Cellular immune response during uncomplicated genital infection with Chlamydia trachomatis in humans. 总被引:6,自引:13,他引:6 下载免费PDF全文
R C Brunham D H Martin C C Kuo S P Wang C E Stevens T Hubbard K K Holmes 《Infection and immunity》1981,34(1):98-104
Extraction of staphylococcal abscesses by the Folch procedure revealed that all of the staphylocidal activity was present in the lipid fraction. Further separation of the lipids indicated that the bactericidal activity resided in the free fatty acid pool. Lipids similarly extracted from mesenteric or epididymal fat tissue, either before of after activation, did not possess comparable activity. Myristic, palmitic, palmitoleic, linoleic, and oleic acids, as well as lysolecithin, also failed to exhibit the properties of the fatty acid fraction obtained from abscess homogenates. These findings suggest the staphylocidal fatty acid is not a common host lipid. 相似文献
26.
27.
Liu CS Chen HW Lii CK Tsai CS Kuo CL Wei YH 《Environmental and molecular mutagenesis》2002,40(3):168-174
The effects of long-term smoking on mitochondrial DNA (mtDNA) deletions in hair follicles were investigated in subjects with different antioxidant capacity. Twenty-two male smokers with a smoking index of greater than 5 pack-years and without any known systemic diseases were recruited for this study. Forty healthy nonsmoking males were included as controls. We found that the concentrations of ascorbate and alpha-tocopherol and the activities of glutathione S-transferase (GST) and glutathione peroxidase in blood plasma were significantly decreased in smokers. The levels of glutathione and protein thiols in whole blood and the incidence of a 4,977 bp deletion of mtDNA (dmtDNA) in hair follicles were significantly increased in smokers. A significantly higher incidence of the 4,977 bp dmtDNA was found in smokers with plasma GST activity less than 5.66 U/l (OR = 7.2, P = 0.020). Using multiple covariate ANOVA and logistic regression, we found that age and low plasma GST activity were the only two risk factors for the 4,977 bp dmtDNA. These results suggest that smoking depletes antioxidants and causes mtDNA deletions and that plasma GST may play an important role in the preservation of the mitochondrial genome in tissue cells of smokers. 相似文献
28.
Colonial dissociation and susceptibility to phagocytosis of Pseudomonas aeruginosa grown in a chamber implant model in mice. 总被引:1,自引:4,他引:1 下载免费PDF全文
N M Kelly J L Battershill S Kuo J P Arbuthnott R E Hancock 《Infection and immunity》1987,55(11):2841-2843
Pseudomonas aeruginosa strains were grown in 1-cm plastic chambers sealed at both ends with porous Millipore filters and implanted in the peritonea of mice. Mucoid and nonmucoid strains of P. aeruginosa isolated from a patient with cystic fibrosis largely retained their phenotypes when grown for up to 1 year in this in vivo system, although colonial dissociation occurred, as observed in chronic lung infections of patients with cystic fibrosis. In the absence of added opsonins, P. aeruginosa M2 cells taken directly from the in vivo system were significantly more susceptible to phagocytosis than were the same P. aeruginosa cells after being washed in buffer. Phagocytosis of in vivo-grown P. aeruginosa cells could be further enhanced by using a porin protein F-specific monoclonal antibody. 相似文献
29.
Systemic Chlamydia trachomatis infection in mice: a comparison of lymphogranuloma venereum and trachoma biovars. 总被引:1,自引:7,他引:1 下载免费PDF全文
We developed a murine model of systemic infection with Chlamydia trachomatis biovar lymphogranuloma venereum (LGV). The pathological features of this infection resemble those of human LGV infection since both are characterized by granuloma formation. Mice developed resistance to reinfection with LGV, and this resistance was based on cellular immune mechanisms since it was transferable with immune spleen cells but not with immune serum. Resistance required viable organisms for induction. We compared LGV biovar infection with trachoma biovar infection. Trachoma biovar produced similar but less marked microbiological and pathological features. Cross-immunity was less apparent between serovars from trachoma and LGV biovars than it was between serovars within the same biovar. This model of systemic C. trachomatis infection will be useful in exploring virulence features of LGV. 相似文献
30.
Cytokine responses during mycobacterial and schistosomal antigen-induced pulmonary granuloma formation. Production of Th1 and Th2 cytokines and relative contribution of tumor necrosis factor. 总被引:6,自引:4,他引:6 下载免费PDF全文
S. W. Chensue K. Warmington J. Ruth P. Lincoln M. C. Kuo S. L. Kunkel 《The American journal of pathology》1994,145(5):1105-1113
Synchronized pulmonary granulomas (GRs) were induced in presensitized mice by intravenous embolization of polymer beads bound with purified protein derivative (PPD) of Mycobacteria tuberculosis or soluble antigens derived from Schistosoma mansoni eggs (SEA). Uncoated beads served as a foreign body control (CON). Antigen-coated beads elicited GRs with characteristic epithelioid macrophages and multinucleate giant cells by 4 days after embolization. Unlike PPD GR, SEA bead lesions contained eosinophils, whereas CON beads elicited only a limited mononuclear infiltrate. GRs and draining lymph nodes (LN) were assessed on days 2, 4, and 8 for Th1-(interleukin-2 [IL-2], interferon-gamma[IFN] and Th2-type (IL-4, IL-5, and IL-10) cytokines. CON GR produced only a small amount of IFN-gamma on day 2 and failed to induce a significant response in draining LN. In contrast, both PPD and SEA antigen-coated beads induced reactive lymphoid hyperplasia but differed greatly in local and regional cytokine profiles. PPD GR produced IFN-gamma on day 2 and the draining LN produced predominantly Th1 cytokines on days 2 and 4. In contrast, SEA beads GRs were dominated by Th2 cytokines. The corresponding LN produced IL-2 and IL-4 on day 2; IL-2, IL-4, IFN-gamma, and IL-10 on day 4; then IL-2, IFN-gamma, and IL-4 on day 8, probably reflecting maturational changes of T cells. Macrophages (MP) from bead GR also showed different patterns of IL-6 and tumor necrosis factor (TNF) production. Compared with CON GR, MPs from PPD GR were weak sources of IL-6, whereas those of SEA GR showed enhanced and accelerated production. In contrast, MP of PPD GR had augmented TNF-producing capacity, whereas those of SEA GR showed delayed TNF production. In vivo depletion of TNF, respectively, caused 40 and 10% decreases in PPD GR and SEA GR but had no effect on CON GR area, indicating that TNF contributed to a greater degree to the PPD response. These data show that depending on the inciting agent, GR can be mediated by different cytokines. Characterization of inflammatory lesions by cytokine profiles should allow design of more rational therapeutic interventions. 相似文献