首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   175470篇
  免费   6672篇
  国内免费   346篇
耳鼻咽喉   3085篇
儿科学   6554篇
妇产科学   4444篇
基础医学   24783篇
口腔科学   4919篇
临床医学   13024篇
内科学   31861篇
皮肤病学   4705篇
神经病学   16219篇
特种医学   8921篇
外国民族医学   24篇
外科学   28935篇
综合类   1112篇
一般理论   43篇
预防医学   8721篇
眼科学   4704篇
药学   12102篇
中国医学   352篇
肿瘤学   7980篇
  2023年   767篇
  2021年   1326篇
  2020年   1169篇
  2019年   1371篇
  2018年   2898篇
  2017年   2420篇
  2016年   3363篇
  2015年   3728篇
  2014年   3963篇
  2013年   5520篇
  2012年   8529篇
  2011年   7980篇
  2010年   4719篇
  2009年   3819篇
  2008年   7908篇
  2007年   8765篇
  2006年   8790篇
  2005年   9203篇
  2004年   8790篇
  2003年   8667篇
  2002年   8544篇
  2001年   6349篇
  2000年   6430篇
  1999年   5549篇
  1998年   1650篇
  1997年   1368篇
  1996年   1044篇
  1995年   853篇
  1994年   795篇
  1992年   2468篇
  1991年   2391篇
  1990年   2358篇
  1989年   2191篇
  1988年   1917篇
  1987年   1913篇
  1986年   1755篇
  1985年   1693篇
  1984年   1328篇
  1983年   1066篇
  1979年   1415篇
  1978年   1034篇
  1977年   887篇
  1975年   1100篇
  1974年   1136篇
  1973年   1039篇
  1972年   1042篇
  1971年   1011篇
  1970年   898篇
  1969年   840篇
  1968年   808篇
排序方式: 共有10000条查询结果,搜索用时 32 毫秒
31.
The authors' 5-year experience in the management and care of prostatic carcinoma are summarized. Their method differs essentially from earlier practice. They have found a new diagnostic and therapeutic method by introducing the TECO irradiation therapy, extensively using bone scintigraphy, by introducing cytostatics, extensively applying the prostate-specific acid phosphatase and by performing rectal biopsy of the prostate. They describe their own observations on the diagnostics and therapy of prostatic carcinoma. They stress that none of the therapies is the method of choice, the use of the various kinds of treatment are defined by strict indications. They state that care of prostatic cancer patients is highly important because only observation of the course of the disease may ensure the evaluation of treatment results and the indication of the adequate therapeutic method.  相似文献   
32.
33.
The atomic rearrangement cascade that follows the electron-capture decay process in low-Z radionuclides involves X-rays which have high photoelectric interaction probabilities. When the K-shell binding energy of the ionized atom (e.g., hydrogen) is significantly lower than the energy of the X-ray photon, the detector response to a photon-equivalent energy electron and the whole photoionization process are very similar. This is not the case when the scintillator cocktail contains larger atoms (e.g., oxygen and phosphorus in Ultima Gold). For larger Z atoms, the reduced energy of the whole photoionization process is less than the reduced energy of the interacting photon due to the nonlinear effects of ionization quenching. This paper shows the convenience of including a more detailed simulation of the photoionization process in the atomic rearrangement detection model for electron-capture nuclides such as (55)Fe, (51)Cr and (54)Mn. The need for more elaborate atomic rearrangement models is a consequence of the analysis of (125)I data.  相似文献   
34.
35.
36.
OBJECTIVE: To introduce 1,1,1,2 tetrafluoroethane (TFE), as a new material for cryosurgery of gingival melanin pigmentation (GMP). STUDY DESIGN: Twenty-one patients with GMP were treated using a TFE-cooled cotton swab. Standard digital images of pigmented areas were measured preoperatively and postoperatively with image-analyzing software. The Mann-Whitney U test was used for statistical analysis. RESULTS: Keratinization was completed 3 to 4 weeks after application, without any trace of pigmentation. Statistical analysis revealed a significant difference between preoperative and postoperative measurements of pigmented areas (P < .05). During the follow-up period, no side effects were observed and improved esthetics were maintained up to month 30. CONCLUSIONS: The clinical outcomes of cryosurgery with TFE for treatment of GMP are very satisfactory. The use of TFE for cryosurgical treatment of GMP is practical and inexpensive. Moreover, unlike other cryosurgery methods no special equipment is required, and it is safe to store in the dental clinic.  相似文献   
37.
K Rehse  U Lükens  G Claus 《Archiv der Pharmazie》1987,320(12):1233-1238
Platelet Aggregation Inhibiting and Anticoagulant Effects of Oligoamines, VII: Benzene-1,3,5-trialkanamines Seventeen title compounds were synthesized. Platelet aggregation induced by collagen in vitro is inhibited by 9 of them at IC50 = 2–4 μmol/L. Seven compounds depress the formation of fibrin to ≦ 25 % of normal in concentrations below 50 μmol/L. Compound 15 [4-(2-thienylbutyl)benzene-1,3,5-trimethanamine is the first oligoamine which shows anticoagulant and antiplatelet effects at the same concentration (25 μmol/L).  相似文献   
38.
In the operative treatment of appendicitis the so called negative appendectomy is an important issue because of its increased morbidity. From the hypothesis that the intestinal diamine oxidase activity is a suitable marker of mucosal integrity, the distribution pattern of the enzyme in appendices histologically classified as inflamed or not inflamed was studied. Histologically apparent inflammation of the appendix was connected with a significant reduction of diamine oxidase activity. The determination of this enzymic activity may be a simple and sensitive test for mucosal inflammation of the appendix even at a very early state. This could reduce the rate of negative appendectomies and influence thereby risk-cost-benefit calculations.  相似文献   
39.
40.
In the present paper, the results obtained are shown after a study by means of multivariant statistical analysis, of the quantity of Eimeria spp. oocyst elimination in sheep, bearing in mind the variations observed in the different areas, in the different age-groups, from month to month, and from year to year. Climatic factors, development of immunity, lambing seasons, and poor hygienic conditions seem to be the factors responsible for the statistically significant differences found when analysing the aforementioned main effects.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号