全文获取类型
收费全文 | 4848篇 |
免费 | 434篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 194篇 |
妇产科学 | 59篇 |
基础医学 | 557篇 |
口腔科学 | 76篇 |
临床医学 | 522篇 |
内科学 | 936篇 |
皮肤病学 | 51篇 |
神经病学 | 331篇 |
特种医学 | 441篇 |
外科学 | 611篇 |
综合类 | 131篇 |
一般理论 | 3篇 |
预防医学 | 464篇 |
眼科学 | 135篇 |
药学 | 320篇 |
中国医学 | 10篇 |
肿瘤学 | 460篇 |
出版年
2022年 | 49篇 |
2021年 | 107篇 |
2020年 | 55篇 |
2019年 | 117篇 |
2018年 | 94篇 |
2017年 | 67篇 |
2016年 | 96篇 |
2015年 | 100篇 |
2014年 | 132篇 |
2013年 | 214篇 |
2012年 | 256篇 |
2011年 | 247篇 |
2010年 | 156篇 |
2009年 | 134篇 |
2008年 | 222篇 |
2007年 | 230篇 |
2006年 | 246篇 |
2005年 | 229篇 |
2004年 | 225篇 |
2003年 | 221篇 |
2002年 | 169篇 |
2001年 | 182篇 |
2000年 | 143篇 |
1999年 | 115篇 |
1998年 | 72篇 |
1997年 | 57篇 |
1996年 | 54篇 |
1995年 | 47篇 |
1994年 | 52篇 |
1993年 | 52篇 |
1992年 | 66篇 |
1991年 | 66篇 |
1990年 | 56篇 |
1989年 | 74篇 |
1988年 | 65篇 |
1987年 | 84篇 |
1986年 | 50篇 |
1985年 | 61篇 |
1984年 | 51篇 |
1983年 | 44篇 |
1982年 | 35篇 |
1981年 | 36篇 |
1980年 | 37篇 |
1979年 | 25篇 |
1978年 | 38篇 |
1977年 | 39篇 |
1976年 | 31篇 |
1975年 | 31篇 |
1974年 | 29篇 |
1972年 | 32篇 |
排序方式: 共有5315条查询结果,搜索用时 15 毫秒
41.
Dr. Robert Law 《Pflügers Archiv : European journal of physiology》1972,334(4):303-309
Summary The intrarenal volumes of distribution of125I-polyvinyl pyrrolidone and51Cr-labelled red cells have been examined in rabbits under conditions of severe hydropenia and starvation-induced polyuria, and in rabbits under control conditions. The PVP space was significantly reduced, and the ratio [red cell space]:[red cell space + PVP space] significantly elevated, in the outer cortex of kidneys of hydropenic rabbits, and in the papilla of polyuric rabbits. It is suggested that the former may in some manner result from a reduction in the total cortical vascular space, whereas the latter reflects variations of medullary and appillary interstitial tonicity under these conditions. 相似文献
42.
Outbreak of serogroup C meningococcal disease caused by a variant of Neisseria meningitidis serotype 2a ET-15 in a community of men who have sex with men 下载免费PDF全文
Tsang RS Kiefer L Law DK Stoltz J Shahin R Brown S Jamieson F 《Journal of clinical microbiology》2003,41(9):4411-4414
We describe an outbreak, in a community of men who have sex with men, of serogroup C meningococcal disease caused by a genetic variant of the serotype 2a ET-15 Neisseria meningitidis characterized by a point mutation in the gene coding for the serotype 2a antigen. A microbiological characterization of the outbreak strain is presented in this report. 相似文献
43.
Reactive hemophagocytic syndrome is a clinico-pathologic entity characterized by systemic proliferation of non-neoplastic histiocytes showing phagocytosis of hemopoietic cells, resulting in blood cytopenia. It is best known to be associated with virus infection, but other associated diseases have also been implicated. The clinical and pathological findings of 7 fatal cases are described. The syndrome affected both sexes of a wide age range, and all patients had fever. Significant laboratory findings were blood cytopenia, abrupt drop in the blood cell counts, deranged liver function tests and abnormal coagulation profile. The associated diseases were diverse: two patients had bacterial infection; two had peripheral T-cell lymphoma; one had disseminated undifferentiated carcinoma of the ovary; one had both tuberculosis and disseminated nasopharyngeal carcinoma, and one had no obvious underlying disease. It is postulated that lymphokines secreted by lymphoid cells or tumor cells may be responsible for the systemic activation of histiocytes. The differential diagnosis from malignant histiocytosis is discussed. 相似文献
44.
45.
Mak JC Leung HC Ho SP Law BK Lam WK Tsang KW Ip MS Chan-Yeung M 《The Journal of allergy and clinical immunology》2004,114(2):260-264
BACKGROUND: Patients with asthma generate an increased amount of reactive oxygen species from peripheral blood cells. Reactive oxygen species produce many of the pathophysiologic changes associated with asthma and may contribute to its pathogenesis. OBJECTIVE: We investigated changes in antioxidant enzyme activities and oxidized glutathione (glutathione disulfide; GSSG) levels in erythrocytes from a group of healthy control Chinese subjects (n=135) and patients with asthma (n=106). METHODS: Baseline pulmonary function was measured for all subjects. Antioxidant status was evaluated by measuring erythrocyte superoxide dismutase, catalase, and glutathione peroxidase activities. Oxidative stress was also measured in terms of GSSG in erythrocytes with a kinetic microassay. RESULTS: Patients with asthma had significantly increased erythrocyte superoxide dismutase and catalase activities compared with controls (61.10 +/- 1.30 U/g hemoglobin [Hb] vs 55.51 +/- 1.82 U/g Hb [P=.018] and 0.0637 +/- 0.0021 U/g Hb vs 0.0257 +/- 0.0120 U/g Hb [P <.001] for the asthma and control groups, respectively). Conversely, erythrocyte glutathione peroxidase activity decreased (44.21 +/- 1.33 mU/g Hb vs 50.07 +/- 1.39 mU/g Hb for the asthma and control groups, respectively; P=.003). Patients with asthma also had significantly higher GSSG levels in erythrocyte hemolysates compared with controls (167.40 +/- 2.93 micromol/L vs 44.98 +/- 0.44 micromol/L for the asthma and control groups, respectively; P <.001), indicating increased oxidative stress. CONCLUSIONS: Asthma is accompanied by an alteration in systemic antioxidant status due to possible oxidative stress in this disease. 相似文献
46.
Cloning and expression of the major secreted cathepsin B-like protein from juvenile Fasciola hepatica and analysis of immunogenicity following liver fluke infection 下载免费PDF全文
Law RH Smooker PM Irving JA Piedrafita D Ponting R Kennedy NJ Whisstock JC Pike RN Spithill TW 《Infection and immunity》2003,71(12):6921-6932
The functions of the cathepsin B-like proteases in liver flukes are unknown and analysis has been hindered by a lack of protein for study, since the protein is produced in small amounts by juvenile flukes. To circumvent this, we isolated and characterized a cDNA encoding the major secreted cathepsin B from Fasciola hepatica. The predicted preproprotein is 339 amino acids in length, with the mature protease predicted to be 254 amino acids long, and shows significant similarity to parasite and mammalian cathepsin B. Only one of the two conserved histidine residues required for cathepsin B exopeptidase activity is predicted to be present. Recombinant preproprotein was produced in yeast, and it was shown that the recombinant proprotein can undergo a degree of self-processing in vitro to the mature form, which is active against gelatin and synthetic peptide substrates. The recombinant protein is antigenic in vaccinated rats, and antibodies to the protein are detected early after infection of rats and sheep with F. hepatica. The kinetics of the response to cathepsin B and cathepsin L after infection of sheep and rats confirm the temporal expression of these proteins during the life cycle of the parasite. 相似文献
47.
BACKGROUND. Research suggests that patients are more satisfied with patient-centred consultations than with doctor-centred consultations and that some health measures are positively influenced by this type of consultation. Research on the factors that influence the patient centredness of the consultation is sparse but suggests that women doctors are more patient centred than men doctors. AIM. A study was designed, first, to confirm or reject the suggestion that women general practitioners are more patient centred than men general practitioners and, secondly, to determine some of the factors that might influence the patient centredness of a general practitioner. METHOD. The audiotaped consultations of 41 general practitioners were analysed using an instrument designed to measure patient centredness. The general practitioners were selected from a group of volunteers to represent both sexes as well as a wide range of age and experience. RESULTS. The results of the analysis showed that women general practitioners, particularly trainers, had higher patient-centredness scores than men general practitioners. This behaviour is characterized by an increased frequency of open questions and greater attention to patient offers (anything of potential significance that a patient brings to the general practitioner consultation). Additionally, the combination of sexes in a consultation seemed to have an effect on the interaction, with woman general practitioner/female patient dyads (pairings) having the highest median patient-centredness score, woman general practitioner/male patient and man general practitioner/male patient dyads scoring the same as each other and man general practitioner/female patient dyads having the lowest median scores. CONCLUSION. The results suggest that women general practitioners, in this sample, were more patient centred than men general practitioners. The results also suggest that inherent inequalities exist, with female patients receiving a more patient-centred service from general practitioners of their own sex than from general practitioners of the opposite sex. Male patients, on the other hand, seemed to fare equally well, irrespective of the sex of their general practitioner. Training is required to address these inequalities and to improve the level of patient centredness in the consultation. 相似文献
48.
Hydrosalpinges adversely affect markers of endometrial receptivity 总被引:22,自引:10,他引:22
Meyer WR; Castelbaum AJ; Somkuti S; Sagoskin AW; Doyle M; Harris JE; Lessey BA 《Human reproduction (Oxford, England)》1997,12(7):1393-1398
While in-vitro fertilization (IVF) was initially developed in women with
tubal factor infertility, recent clinical studies have suggested that the
presence of hydrosalpinges lowers implantation and pregnancy rates. We
postulated that these hydrosalpinges cause impaired endometrial
receptivity. A total of 103 women with hydrosalpinges were prospectively
evaluated, and compared with 55 infertile and 44 fertile controls. All
women had endometrial biopsies during the window of implantation, analysed
by conventional histological criteria, and also stained for three integrin
markers of endometrial receptivity (alpha1beta1, alpha4beta1 and alpha
vbeta3). Women with hydrosalpinges (cases) expressed significantly less of
the alpha vbeta3 integrin compared with controls. There was no difference
in expression of alpha1beta1 or alpha4beta1 among groups. A significantly
greater number of cases had out of phase histology and missing alpha vbeta3
(type I defects) and absent integrin expression despite normal histological
maturation (type II) defects, compared with controls. Of 20 women with
impaired endometrial receptivity who were also biopsied after hydrosalpinx
surgery, 70% demonstrated increased alpha vbeta3 expression. Seventy-seven
percent of type I and 57% of type II defects were corrected
postoperatively. Using markers of endometrial receptivity, this study
demonstrates that inflammatory hydrosalpinges have an adverse effect on
endometrial receptivity, which in some cases may be overcome by surgical
treatment of the hydrosalpinx.
相似文献
49.
50.
Pseudoangiomatous stromal hyperplasia (PASH) is an uncommon lesion usually found in premenopausal women. Histologically, it is characterized by complex, anatomosing, empty slit-like spaces in a dense collagenous stroma. These pseudoangiomatous spaces are lined by monomorphic spindle cells of myofibroblastic differentiation. Cytological features of PASH are rarely discussed and reported, and may pose diagnostic challenge to surgical pathologists. Two cases of PASH are reported with emphasis on the FNAC features and cytologic differentiation from other benign fibroepithelial lesions. 相似文献