全文获取类型
收费全文 | 1107974篇 |
免费 | 82670篇 |
国内免费 | 2710篇 |
专业分类
耳鼻咽喉 | 14871篇 |
儿科学 | 38296篇 |
妇产科学 | 31128篇 |
基础医学 | 162269篇 |
口腔科学 | 31568篇 |
临床医学 | 99674篇 |
内科学 | 213400篇 |
皮肤病学 | 26347篇 |
神经病学 | 90600篇 |
特种医学 | 43268篇 |
外国民族医学 | 305篇 |
外科学 | 166126篇 |
综合类 | 24218篇 |
一般理论 | 418篇 |
预防医学 | 84083篇 |
眼科学 | 25045篇 |
药学 | 79811篇 |
3篇 | |
中国医学 | 2207篇 |
肿瘤学 | 59717篇 |
出版年
2019年 | 8487篇 |
2018年 | 13043篇 |
2017年 | 10321篇 |
2016年 | 12095篇 |
2015年 | 12899篇 |
2014年 | 16978篇 |
2013年 | 26633篇 |
2012年 | 34893篇 |
2011年 | 37565篇 |
2010年 | 22250篇 |
2009年 | 19931篇 |
2008年 | 35574篇 |
2007年 | 37633篇 |
2006年 | 37835篇 |
2005年 | 36400篇 |
2004年 | 35294篇 |
2003年 | 34197篇 |
2002年 | 33103篇 |
2001年 | 50681篇 |
2000年 | 52787篇 |
1999年 | 42938篇 |
1998年 | 12336篇 |
1997年 | 11019篇 |
1996年 | 10910篇 |
1995年 | 10398篇 |
1994年 | 9687篇 |
1993年 | 9029篇 |
1992年 | 32802篇 |
1991年 | 31942篇 |
1990年 | 31470篇 |
1989年 | 30355篇 |
1988年 | 27575篇 |
1987年 | 27796篇 |
1986年 | 25807篇 |
1985年 | 25152篇 |
1984年 | 18919篇 |
1983年 | 15973篇 |
1982年 | 9783篇 |
1981年 | 8846篇 |
1979年 | 17250篇 |
1978年 | 12582篇 |
1977年 | 10726篇 |
1976年 | 10106篇 |
1975年 | 10530篇 |
1974年 | 12655篇 |
1973年 | 12136篇 |
1972年 | 11110篇 |
1971年 | 10371篇 |
1970年 | 9598篇 |
1969年 | 8925篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
991.
Dr. med. F. Angehrn H. -R. Schultheiss B. Blum 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》1986,367(2):113-118
Zusammenfassung Die posttraumatische Pneumatocele ist eine seltene intrapulmonale Veränderung nach stumpfem Thoraxtrauma. Anhand eines gut dokumentierten Falles wird diese seltene Form der Lungenkontusion dargestellt und die klinisch bedeutsame Differentialdiagnose diskutiert.
Traumatic pneumatocele — a case report
Summary The posttraumatic pneumatocele is a rare intrapulmonary lesion following blunt thoracic injury. By means of a well documented case report this rare form of lung contusion is demonstrated and the clinically important differential diagnosis is discussed.相似文献
992.
National Programme of Research in Human Reproduction S.K. Banerjee R. Baveja R.V. Bhatt A. Chatterjee S.D. Choudhury B. Coyaji A.D. Engineer M.P. Gogoi V. Hingorani K. Lal M. Kochhar U. Krishna P. Misra F.S. Philips R. Rajan P.C. Sen Gupta K. Zaveri S. Datey S. Gupta S. Mehta N.C. Saxena B.N. Saxena 《Contraception》1986,34(6):573-582
The return of fertility following discontinuation of norethisterone oenanthate (NET EN) 200 mg injectable contraceptive after use for a minimum period of six months or more was studied in 69 women who discontinued the method for planning pregnancy. Former users of copper intra-uterine device (CuT 200) were enrolled as a control group. Another 161 women who had discontinued NET EN due to other reasons (e.g. amenorrhoea, excessive bleeding or personal reasons) were also studied for return of fertility after ensuring that they were not using any other method of contraception and were exposed to the risk of pregnancy. The subjects from both groups were followed for a period of one year. The cumulative conception rates at one year were 72.5 and 83.6 per 100 subjects for ex-NET EN and ex-CuT 200 users who had discontinued the method for planning pregnancy and this difference was not statistically significant (P > 0.05). The median time for conception for ex-NET EN users was 7.8 months as compared to 3.7 months in ex-CuT 200 users but the cumulative conception rates at the end of one year show that future return of fertility in NET EN users does not appear to be adversely affected.
In 51 subjects who had discontinued NET EN due to amenorrhoea, the return of fertility was predictably slower and less. The return of fertility in subjects who discontinued NET EN for other reasons (e.g. excessive bleeding and other personal reasons) was similar to ex-NET EN and ex-CuT 200 users. 相似文献
993.
994.
It is still not known how T cells are activated, which T-cell surface structures transmit activation signals, and if antigen-presenting cells possess activation structures for T cells. We have studied whether the T-cell receptor (TcR) must be engaged for T-cell activation to occur. By using membrane-incorporated monoclonal antibodies, we artificially forced T cells to bind to antigen-presenting cells in a mixed lymphocyte reaction system and thereby bypassed the need for TcR engagement and also made it possible for any surface molecule on antigen-presenting cells to deliver a stimulatory signal to the T cells. Theoretically, T cells would become polyclonally activated by this procedure. However, we found that they did not, even though they were intimately bound to the antigen-presenting cell, thus demonstrating that the TcR must participate in antigen/MHC binding in order for the T cells to become activated. This study does not exclude the possibility that antigen-presenting cells possess structures that can activate T cells. 相似文献
995.
996.
L B Warneke 《Revue canadienne de psychiatrie》1991,36(3):194-205
Both abuse and new uses for benzodiazepines are reviewed. The pharmacology of benzodiazepines is summarized and statistics regarding their general use are given. The question of benzodiazepine abuse is reviewed in some detail and the question of rebound, recurrence of symptoms and physiological withdrawal is differentiated. Benzodiazepines are regarded as a very safe class of drugs and the abuse potential is felt to be negligible provided that they are prescribed for appropriate conditions and monitored carefully. The dangers of alternatives to benzodiazepines such as alcohol or barbiturates is emphasized. New uses for benzodiazepines are reviewed including the use of benzodiazepines in panic disorder, as well as an adjunct in the therapy of mania and some psychotic states. Rational prescribing of benzodiazepines is encouraged and the attitude that these are dangerous and addictive drugs is discouraged and put into perspective. 相似文献
997.
H N Qian J Feng H Cui B S Gao S L Qin T Y Fu P Wei Z Y Fu S M Gao Z Y Yang 《中华医学杂志(英文版)》1991,104(2):109-113
Monoclonal antibody 131I-COC183B2, developed in our laboratory and proved to fit for human treatment was injected intraperitoneally or subcutaneously in 13 patients. In 8 cases with i.p. injection the disease corresponded with the image, i.e. 3 primary ovarian epithelial cancers showed positive images, 1 ovarian Krukenberg tumor was negative and the other 4 negative images included 1 uterine myoma and 3 ovarian teratomas. In the subcutaneous injection group, 4 cases had ovarian carcinoma, surgery and chemotherapy. Two negative images corresponded with the clinical status-in good health, another negative case had metastatic left supraclavicular lymph node due to ovarian mucinous adenocarcinoma. The last negative image in this group was a case of benign ovarian teratoma which was proved after surgery. The 1 positive case was waiting to be proved by a scheduled third operation. The computer scintigram calculation of T/NT was 5.35 to 13.7. The results suggest that this monoclonal antibody can be used for radioimmunoimaging for the localization of ovarian carcinoma, which is not only helpful for clinical staging and differential diagnosis but is also a good follow-up method.
相似文献
998.
999.
J P Dutcher C E Riggs J J Strauman B Link P H Wiernik 《Clinical pharmacology and therapeutics》1989,45(4):424-428
In a phase I-II study, 21 patients with relapsed or refractory acute leukemia were treated with 4'-deoxydoxorubicin (esorubicin), the 4'-deoxy derivative of doxorubicin. Four of 14 evaluable patients with acute nonlymphocytic leukemia (ANLL) in relapse or refractory to other anthracyclines achieved partial response (28.5%). Pharmacokinetics were similar to those of the parent compound, doxorubicin. Esorubicin has activity in ANLL and has pharmacologic properties comparable to those of other anthracyclines. Dose-limiting toxicity occurs in the form of mucositis, which may limit its use in combination with other antileukemic drugs. 相似文献
1000.
Isolation and characterization of a distinct immunoregulatory isoform of alpha-fetoprotein produced by the normal fetus 总被引:1,自引:1,他引:0
下载免费PDF全文
![点击此处可从《The Journal of experimental medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In this report, we examine the functional significance of the molecular microheterogeneity of alpha-fetoprotein (AFP). In doing so, we have taken the direct approach of purifying the naturally occurring isomeric forms of fetal-derived AFP using a preparative anion exchange column linked to an automated fast protein liquid chromatography (FPLC) system followed by parallel testing of each isolated molecular variant for in vitro immunoregulatory activity. The data obtained demonstrate the presence of seven distinct variants of AFP as defined by their retention volumes on FPLC elution profiles, by their pIs on analytical IEF gels, and by Western blot analysis. Molecular mass determination by SDS-PAGE showed each isomer to be equivalent in size to 69,000-dalton native unfractionated AFP molecules. All the immunosuppressive activity of AFP was localized to a single variant representing only 6% of the total composition of native AFP. The immunoregulating isomer termed AFP-1 was the least acidic of the seven isolated variants with a pI of 5.1 and displayed a sialic acid content of 1 mol/mol of protein. The inhibitory activity of AFP-1 could be readily measured on T cell-dependent antibody synthesis, Con A-induced stimulation of Lyt-1+23- thymocyte DNA synthesis, and lymphokine-activated NK cell activity. All other isomers were without effect in these test systems. The immunosuppressive AFP-1 isomer also displayed the strongest growth-promoting influence on cultured bone marrow lymphocytes. There was no correlation between functional activity and degree of expression of sialic acid residues on the AFP molecules. These findings demonstrate that the immunoregulating function of AFP is confined to a distinct and relatively small subpopulation of native AFP molecules and should therefore contribute to the resolution of outstanding questions regarding the structure/function relationship of this onco-fetal glycoprotein. 相似文献