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   17468篇
  免费   1120篇
  国内免费   35篇
耳鼻咽喉   355篇
儿科学   470篇
妇产科学   488篇
基础医学   2547篇
口腔科学   320篇
临床医学   1572篇
内科学   3042篇
皮肤病学   589篇
神经病学   1774篇
特种医学   830篇
外科学   2764篇
综合类   149篇
一般理论   20篇
预防医学   1122篇
眼科学   468篇
药学   967篇
中国医学   8篇
肿瘤学   1138篇
  2022年   160篇
  2021年   309篇
  2020年   157篇
  2019年   282篇
  2018年   337篇
  2017年   254篇
  2016年   324篇
  2015年   327篇
  2014年   473篇
  2013年   602篇
  2012年   841篇
  2011年   892篇
  2010年   526篇
  2009年   479篇
  2008年   771篇
  2007年   878篇
  2006年   802篇
  2005年   792篇
  2004年   714篇
  2003年   679篇
  2002年   698篇
  2001年   553篇
  2000年   533篇
  1999年   502篇
  1998年   221篇
  1997年   217篇
  1996年   182篇
  1995年   165篇
  1994年   157篇
  1993年   128篇
  1992年   351篇
  1991年   341篇
  1990年   288篇
  1989年   307篇
  1988年   258篇
  1987年   240篇
  1986年   273篇
  1985年   239篇
  1984年   177篇
  1983年   144篇
  1982年   107篇
  1981年   97篇
  1979年   143篇
  1978年   106篇
  1976年   92篇
  1975年   94篇
  1974年   113篇
  1973年   109篇
  1972年   95篇
  1971年   98篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Birth of Healthy Children After Preimplantation Diagnosis of Thalassemias   总被引:12,自引:0,他引:12  
Background: Preimplantation genetic diagnosis (PGD) allows couples at risk of having children with thalassemia to ensure the healthy outcome of their pregnancy. Methods: Seventeen PGD clinical cycles were initiated for Cypriot couples at risk of having children with different thalassemia mutations, including IVS1-110, IVSI-6, and IVSII-745. Unaffected embryos for transfer were selected by testing oocytes, using first and second polar body (PB) removal and nested polymerase chain reaction analysis followed by restriction digestion. Results: Unaffected embryos were selected in 16 of 17 PGD cycles. Of 166 oocytes studied from these cycles, 110 were analyzed by sequential analysis of both the first and the second PB, resulting in preselection and transfer of 45 unaffected embryos. This resulted in seven pregnancies and in the birth of five healthy thalassemia-free children. The embryos predicted to have inherited the affected allele were not transferred. Analysis of these embryos confirmed the PB diagnosis. Conclusions: Sequential first and second PB testing of oocytes is reliable for PGD of thalassemia and is a feasible alternative to prenatal diagnosis in high-risk populations.  相似文献   
992.
993.
Zusammenfassung Eingehende Darstellung der Diagnose und bisher bekannten Bedeutung der Alderschen Granulationsanomalie der Leukocyten an Hand zweier neuer Beobachtungen derselben bei Dysostosis multiplex (Pfaundler-Hurlersche Krankheit, gargoylism). Besonders auffällig erscheint der Befund der Alder-Anomalie im Zusammenhang mit ungewöhnlichen röntgenologischen Hüftbefunden. Auf den besonderen Wert der Anomalie als Früh- oder Detektorsymptom wird hingewiesen.  相似文献   
994.
Paclitaxel and concurrent radiation for gastric cancer   总被引:14,自引:0,他引:14  
PURPOSE: To determine the activity and toxicity of paclitaxel and concurrent radiation for gastric cancer. METHODS AND MATERIALS: Twenty-seven patients were studied. Twenty-five had proximal gastric cancers, two had distal cancers. Eight had esophageal extension, 6 had celiac adenopathy, and 7 had retroperitoneal adenopathy. Patients received paclitaxel, 50 mg/m(2) by 3-hour intravenous (IV) infusion, weekly, on days 1, 8, 15, 22, and 29. Radiation was administered concurrently to a total dose of 45.0 Gy, in 1.80 Gy fractions, for 25 treatments. Patients who were medically or surgically inoperable received a sixth week of paclitaxel with a radiation boost to 50.4 Gy. RESULTS: Esophagitis and gastritis were the most important toxicities, Grade 3 in four patients (15%), and Grade 4 in three patients (11%). Five patients (19%) had Grade 3 nausea. The overall response rate was 56%, including three patients (11%) with a complete response. The 2-year progression-free and overall survival rates were 29% and 31%, respectively. CONCLUSION: Concurrent paclitaxel and radiation demonstrates substantial local-regional activity in gastric cancer. Future investigations combining paclitaxel and radiation with other local-regional and systemic treatments are warranted.  相似文献   
995.
This study of etoposide in thyroid cancer was designed to determine the activity and toxicity of etoposide in a variety of inoperable, thyroid hormone insensitive, and radio-iodine resistant primary cancers of the thyroid. The patients were required to have an ECOG performance status of at least 3 and no previous exposure to chemotherapy. The etoposide was given at a dose of 140 mg/m2 daily for 3 days and every 3 weeks until progression. The study was closed after 18 months because of poor accrual. There were no responses seen among the 10 patients accrued. The toxicity was primarily hematologic. There was no evidence of activity of etoposide in thyroid carcinoma, although this study lacked significant power because of the poor accrual.  相似文献   
996.
997.
Cytologic smears (CS) were taken from the lateral border of the tongue of HIV-seropositive patients (HIV+) (n = 39) and of seronegative controls (HIV-) (n = 19) and examined by immunocytochemistry (APAAP) and in situ hybridization (ISH) (biotinylated DNA probes) for the presence of viral antigens/DNA of EBV and CMV. While none of the HIV controls showed positive results for EBV antigen, 61% (APAAP) resp. 79% (ISH) of oral epithelial cells in the group of HIV+ patients were EBV-positive. While all CS taken from areas with the clinical diagnosis of hairy leukoplakia (HL) were EBV positive (APAAP and/or ISH), the detection of EBV in CS from uninvolved oral mucosa seemed to be associated with the later development of HL. In the group of HIV+ patients the detection rate for CMV was about five times (APAAP) resp. three times (ISH) higher than in HIV- persons. This non-invasive technique seems to be a valuable tool to screen for viral antigens/genomes.  相似文献   
998.
Epithelial thymus tumors--therapy and prognosis   总被引:1,自引:0,他引:1  
One hundred and two patients with epithelial thymoma (ET) and carcinoma have undergone surgical treatment since 1957. In this series thymomas were classified according to Masaoka's clinical staging criteria (encapsulated, invasive) and according to Müller-Hermelink's histological criteria of the resected specimens (medullary and cortical differentiation) and compared to clinical symptoms and survival rates (mean follow-up time 66.4 months). We found that it is not always possible to differentiate intraoperatively fibrous adhesions from infiltrations of the thymic capsule or to recognise thymus carcinoma as such macroscopically if they have not already infiltrated the organ's capsule. All ETs with cortical differentiation after thymectomy showed a malignant course; in contrary ETs with medullary differentiation we found without relapses of metastases. ETs with both histological types (hybrid typs) and cortical dominance took in only two out of 57 cases a malignant course though five of them showed an invasion into the capsule according to clinical staging criteria stage II. Therefore classifying ETs only into two categories, encapsulated and invasive, according to surgical and gross findings, seems to be not always possible and insufficient for the clinical assessment of the malignity and prognosis.  相似文献   
999.
Amniotic fluid from 135 pregnancies was assayed for human chorionic gonadotropin (hCG) and its free alpha (ahCG) and free beta (bhCG) subunits. Forty-six chromosomally abnormal pregnancies between 14 and 20 weeks' gestation were matched with 89 chromosomally normal samples. Compared with controls, trisomy 21 pregnancies exhibited significantly elevated levels of all three peptides, whereas trisomy 18 gestations gave rise only to significant elevation of ahCG. Female fetuses in both the trisomy 21 and trisomy 18 pregnancies provided significantly elevated levels of hCG and bhCG compared to their male counterparts. On converting the values to multiples of the median, it was determined that 6 of 7 trisomy 18 samples had abnormally elevated alpha/beta ratios, as did 6 of 21 Down's syndrome pregnancies. Further, 11 of 21 trisomy 21 gestations had abnormal amniotic fluid hCG levels. Using only ahCG, bhCG and their ratio, a 61 per cent sensitivity was found for these trisomies, with a 96 per cent specificity.  相似文献   
1000.
Zusammenfassung Valproat ist ein weitverbreitetes Antiepileptikum mit einem breiten Indikationsspektrum, bei dessen Anwendung seltene, aber schwere Nebenwirkungen wie das Valproat-assoziierte Leberversagen auftreten k?nnen. Erstes Symptom ist dabei eine Befindlichkeitsst?rung des Patienten. Isolierte Ver?nderungen von Standardlaborparametern der Leber sind kein Frühindikator. Eine frühzeitige Diagnostik der Komplikation ist daher nach heutigem Wissensstand durch prophylaktische Laborkontrollen nicht m?glich. Entscheidend ist die rechtzeitige Erkennung der beginnenden Komplikation auf der Basis klinischer Kriterien, u.U. bei gleichzeitig ver?nderten Laborparametern. Ein sofortiges Absetzen der Valproins?ure und die gleichzeitige Gabe von Carnitin kann zu einer Unterbrechung des sonst fatalen Ablaufs der Komplikation mit anschlie?ender Erholung führen. Im Rahmen einer Konsensuskonferenz wurden der aktuelle Wissensstand über Früherkennung und Therapie der VPA-induzierten Hepatotoxizit?t diskutiert. Die Ergebnisse des Konsensus wurden mit dem Ziel einer Verbessung der Arzneimittelsicherheit in einer Empfehlung über Laborkontrollen, Frühdiagnostik und Therapie zusammengefa?t.   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